MULTIPLE CHOICES QUESTIONS IN Communications Engineering By: S. S. Cuervo & K. L. N. Suello 400 Solved Problems

TRANSMISSION LINES 1. A parallel wire line spaced at 1.27 cm has a diameter of 0.21 cm. what is the characteristic impedance?

a. 300 ohms b. 400 ohms c. 500 ohms d. 600 ohms 2. In a coaxial line if the inner diameter is 0.51 Encoded by: cm and the center conductor has a diameter Pante, Riel Djoshua P. of 0.22 cm. what is the characteristic impedance?

a. 50.1 ohms b. 50.2 ohms c. 50.3 ohms d. 50.4 ohms 3. A strip line is formed using a multilayer Table of Contents board (dielectric constant = 2). The center track is 0.15 inch wide and 0.005 inch thick Transmission Lines 65 problems and the PC board first layer thickness is 0.05 solved inch thick, with an overall board thickness Radio Wave Propagation 39 problems of twice the single layer. What is the solved characteristic impedance? 68 problems solved a. 14.7 ohms Noise 71 problems b. 14.8 ohms solved c. 14.9 ohms Amplitude Modulation 101 problems d. 15.0 ohms solved 4. In an improperly loaded , Frequency Modulation 56 problems determine the power reflected from the load solved if the incident power at the load is 500 W and the reflection coefficient is 0.71. ______a. 252.04 W Total = 400 problems b. 252.05 W solved c. 252.06 W d. 252.07 W 5. In wire communications system, calculate the return loss in dB, if the load impedance is 600 ohms and the characteristic impedance of the line is 300 ohms.

a. 9.52 dB b. 9.53 dB c. 9.54 dB d. 9.55 dB a. 2.13 b. 2.14 6. The VSWR on a loss free line of 50 ohm c. 2.15 characteristic impedance is 4.2. Determine d. 2.16 the value of the purely resistive load 12. What is the characteristic impedance of a impedance which is known to be larger than coaxial cable using a solid polyethylene 50 ohms. dielectric having a relative permeability of 2.3, an inner conductor of 1 mm diameter a. 210 ohms and an outer conductor of diameter 5mm? b. 211 ohms c. 212 ohms a. 63.4 ohms d. 213 ohms b. 63.5 ohms 7. A micro strip line is formed using a 0.095 c. 63.6 ohms inch thick PC board, with a bottom ground d. 63.7 ohms plane and a single 0.15 inch wide, 0.008 13. Calculate the velocity factor of a coaxial inch thick track on the top. What is its cable used as a transmission line, with the characteristic impedance? characteristic impedance of 50 ohms; capacitance is 40 pF/m, and inductance a. 72.1 ohms equal to 50microH/m. b. 72.2 ohms c. 72.3 ohms a. 0.0745 ft d. 72.4 ohms b. 0.0746 ft 8. Determine the impedance of a balanced 2 c. 0.0747 ft wire with unequal diameters d1 = 12 mm d. 0.0748 ft and d2 = 10 mm. the spacing between wires 14. What is the actual length in feet of a one is 30mm. quarter of a coaxial cable with a velocity of 0.69 at 40 MHz? a. 35.35 M ohms b. 35.36 M ohms a. 4.23 ft c. 35.37 M ohms b. 4.24 ft d. 35.38 M ohms c. 4.25 ft 9. For a parallel wire line, determine the d. 4.26 ft conductance if the conductivity is 200 x 10-6 15. What is the actual length in feet of one half S/m and the conductor diameter spacing is of a coax with velocity factor 10mm. of 0.63 at 28 MHz?

a. 1.23mS/m a. 11.07 ft b. 1.24mS/m b. 11.08 ft c. 1.25mS/m c. 11.09 ft d. 1.26mS/m d. 11.10 ft 10. What is the characteristic impedance of an 16. What is the actual length in feet of one open line with conductors 4 mm in diameter quarter wavelength of a coax with a velocity separated by 15 mm? factor of 0.68 at 39 MHz?

a. 241.52 ohms a. 5.577 ft b. 241.53 ohms b. 5.576 ft c. 241.54 ohms c. 5.575 ft d. 241.55 ohms d. 5.574 ft 11. The forward power in a transmission line is 17. What is the actual length in feet of a one half 150 W and the reverse power is 20 W. wavelength of a coax with a velocity factor Calculate the SWR on the line. of 0.61 at 27 MHz? constant of 2.56 a. 11.10 ft b. 11.11 ft a. 98 ohms c. 11.12 ft b. 99 ohms d. 11.13 ft c. 100 ohms 18. What is the actual length in feet of a one half d. 101 ohms wavelength of a coax with a velocity factor 24. What is the characteristic impedance of a of 0.59 at 26 MHz? single wire with diameter d = 0.25 mm placed at the center between grounded a. 11.16 ft parallel planes separated by 1 mm apart? b. 11.17 ft The wire is held by a material with a c. 11.18 ft velocity factor of 0.75. d. 11.19 ft 19. What is the actual length in feet of a one a. 71 ohms quarter wavelength of a coax with a velocity b. 72 ohms factor of 0.695 at 42 MHz? c. 73 ohms d. 75 ohms a. 4.05 ft 25. What is the phase coefficient of a b. 4.06 ft transmission line at the frequency of 10 c. 4.07 ft MHz if the velocity of propagation is 2.5 x d. 4.08 ft 108m/s? 20. An amplifier with a 20 dB gain is connected to another with 10 dB gains by means of a a. 0.25rad/m transmission line with a loss of 4 dB; if a b. 0.26rad/m signal with a power level of 14 dBm were c. 0.27rad/m applied to the system, calculate the power d. 0.28rad/m output. 26. Determine the conductance of a two wire open line with the following parameters; D a. 11dBm = 4 in; d = 0.1 in. and p = 2.6 x108 ohms-m. b. 12dBm c. 13dBm a. 2.75 x 10-9 S/m d. 14dBm b. 2.76 x 10-9 S/m 21. An attenuator has a loss of 26 dB. If a power c. 2.77 x 10-9 S/m of 3 W is applied to the attenuator, find the d. 2.78 x 10-9 S/m output power. 27. What is the input impedance of a transmission line if its characteristic a. 7.54mW impedance is 300 ohms and the load is 600 b. 7.55mW ohms? Assume a quarter wavelength c. 7.56mW sections only. d. 7.57mW 22. What would be the approximate series a. 149 ohms impedance of a quarter wave matching line b. 150 ohms used to match a 600 ohms feed to 70 ohms c. 151 ohms antenna? d. 152 ohms 28. Determine the of a 300 a. 204. 94 ohms ohms line whose load is 400 + j150 ohms. b. 204.95 ohms c. 204.96 ohms a. 1.67 d. 204.97 ohms b. 1.68 23. What is the impedance of a balance 4 wire c. 1.69 with a diameter of 0.25 cm and spaced 2.5 d. 1.70 cm apart using an insulator with a dielectric 29. What proportion of the incident power is reflected back for the load for a 75 ohms line terminated with ZL = 50 – j25 ohms. a. 7.6 cm b. 7.7 cm a. 7.82% c. 7.8 cm b. 7.83% d. 7.9 cm c. 7.84% 36. Calculate the SWR of the line if the d. 7.85% characteristic impedance of the line is 75 30. What is the attenuation of a 50 ohms coaxial ohms and is terminated by 50 ohms. cable if it has a resistance of 0.121 ohms/m? a. 1.4 a. 1.21 x10-3Np/m b. 1.5 b. 1.22 x10-3Np/m c. 1.6 c. 1.23 x10-3Np/m d. 1.7 d. 1.24 x10-3Np/m 37. A sends a 5 W of power to a 75 31. Find the inductance of a 5 meter length ohms line. Suppose the transmitter and the transmission line if its characteristic line is matched but the load is not. impedance is 52 ohms and the capacitance is Determine the power absorbed by the 75pF/m. reflection is 0.75.

a. 1.013uH a. 2.1821 W b. 1.014uH b. 2.1822 W c. 1.015uH c. 2.1823 W d. 1.016uH d. 2.1825 W 32. An open wire transmission line with a 2 mm 38. A generator sends a 250 W of power down a diameter each separated by 12 mm. calculate line. If the SWR of the line is 2.5, determine the characteristic impedance. the power absorbed by the load.

a. 297 ohms a. 204.0 W b. 298 ohms b. 204.1 W c. 299 ohms c. 204.2 W d. 300 ohms d. 204.3 W 33. A coaxial cable with inner diameter of 3 mm 39. A 75 ohm characteristics impedance and an outer diameter of 9 mm. determine transmission line is terminated in by a load the characteristic impedance if the dielectric impedance of 120 ohms. Determine the is polyethylene having ER = 2.3. input impedance looking into the line 1 meter long, if the line has a velocity factor a. 43.2 ohms of 0.9 and operates at a frequency of 50 b. 43.3 ohms MHz. c. 43.4 ohms d. 43.5 ohms a. 34.4 – j12.2 ohms 34. A coaxial transmission line uses Teflon as b. 354 – j12.2 ohms dielectric. What is the propagation velocity c. 36. 4 – j12.2 ohms if the signal? d. 37. 4 – j12.2 ohms 40. A parallel tuned circuit is to be constructed a. 207 x 106 m/s from a shorted section of parallel wire lie. If b. 208 x 106 m/s the operating frequency is 2.4 GHz and c. 209 x 106 m/s dielectric used is polyethylene, what is the d. 210 x 106 m/s length of the shorted section? 35. A 530 MHz signal is propagating along a RG 8/u coaxial cable with a velocity factor a. 2.0622 cm 0.66. If a 75 degree phase shift is needed, b. 2.0623 cm what is the length if the transmission line? c. 2.0624 cm d. 2.0625 cm The voltage at the input end changes to 10 41. The transmitter has an output power of 150 V, with the same polarity as before, at time t W. suppose the line is 50 meters long and = 1.5 micro seconds. What is the resistance perfectly matched with a loss of 3 dB/100m, that terminates the lines? how much power is received in the antenna? a. 465 ohms b. 896 ohms a. 106.1 w c. 563 ohms b. 106.2 w d. 150 ohms c. 106.3 w 47. A parallel wire transmission line has an d. 106.4 w inductance of 120 nH/m and a characteristic 42. TDR equipment receives the signal 250 ns impedance of 320 ohms. Calculate the after the test signal had been transmitted. If capacitance of the line. the discontinuity of the line is found 35 a. 2.25Pf/m meter from the test point, what is the b. 1.17pF/m velocity factor of the line? c. 26.25pF/m d. 15.89pF/m a. 0.933 48. A radio frequency 50 ohms transmission line b. 0.656 is connected to a coil with internal resistance c. 0.588 of 20 ohms and inductive reactance of 5 d. 0.2685 ohms at a frequency of 10 MHz. the line is 43. The line has 97% velocity factor. If the two to be matched to the load by means of a minima are located 30 cm apart, determine quarter wave line and a stub that are the frequency. connected across the load. Calculate the characteristic impedance of the quarter wave a. 485 MHz transformer. b. 488 MHz a. 56.2 ohms c. 478 MHz b. 32.5 ohms d. 456 MHz c. 32.6 ohms 44. The power incident in the line is 20 W. d. 25.3 ohms assuming the reflected power is 15 W what 49. An open wire line has a 3 mm diameter is the SWR of the line? separated 6 mm from each other by an air dielectric. Calculate the characteristic a. 1.71 impedance of the line. b. 1.75 a. 555 ohms c. 1.25 b. 166 ohms d. 1.26 c. 584 ohms 45. A transmission line 90 meter long has a d. 126 ohms characteristic impedance of 75 ohms. The 50. A radio frequency coaxial transmission line line is connected through a 15 V dc has a characteristic impedance of 50 ohms source and 75 ohms source resistance at and is connected across the terminals of a time t = 0. What is the voltage across the signal generator. The sending end voltage is input immediately after t = 0? 10 V. assuming that the generator, line and the load are matched; determine the current a. 0 and 7.5 V which flows into the line. b. 1 and 2.3 V a. 200 ma c. 45 and 29 V b. 562 ma d. 69 and 56V c. 100 ma d. 26 ma 46. A transmission line 90 meter long has a 51. A certain instrument measures the input characteristic impedance of 75 ohms. The impedance of a line and gave a reading of line is connected through a 15 V dc source 1200 ohms when its far end terminals open and 75 ohms source resistance at time = 0. circuited and 300 ohms when it is short circuited. Calculate the characteristic resistive) and which is smaller than 72 impedance of the line. ohms. a. 489 ohms a. 56 ohms b. 600 ohms b. 18ohms c. 259 ohms c. 45ohms d. 546 ohms d. 12ohms 52. A transmission line has an inductance of 253 58. A radio frequency 50 ohms transmission line nH/m and a capacitance of 56 pF/m. if the is connected to a coil with an internal physical length of the line is 1.5 m, calculate resistance of 20 ohms and inductive its electrical length at a frequency of 265 reactance of 5 ohms at a frequency of 10 MHz. MHz. the line is to be matched to the load a. 1.2 by means of a quarter wave line and a stub b. 1.4 that are connected across the load. Calculate c. 1.6 the reactance of the stub. d. 1.5 a. 56.2ohms 53. A radio frequency transmission line has a b. 54.2ohms capacitance of 46. 8 pF/m and a phase c. 83.3ohms constant of 30 degree per meter. Determine d. 12.2ohms the inductance of the line at a frequency of 59. A lossless line has 75 ohms characteristic 30 MHz. impedance and is connected to 50 ohms a. 148Nh/m load. If the sending end current of 1 mA b. 425nH/m flows into the line. Calculate the power c. 165nH/m reflected from the load. d. 125nH/m a. 3uW 54. The reflected current at the load of a b. 4uW mismatched line is 3 mA. If the reflection c. 5uW coefficient of the load is 0.7, what is the d. 6uW incident current? 60. A loss free line transmission line has an a. 4.3 ma inductance of 263.2 nH/m and a capacitance b. 1.2 ma of 46.8 pF/m. if the generator produces a c. 8.2 ma sinusoidal voltage at 3 MHz of 2 V peak, d. 1.7 ma determine the phase change if the line is 3 55. A radio frequency transmission lines has a meter long. characteristic impedance of 75 ohms. If the a. 23.25 degrees line is terminating by an aerial with an input b. 11.34 degrees impedance of 72 ohms, calculate the SWR c. 56.12 degrees of the line. d. 78.2 degrees a. 1.04 61. An AM transmitter sends a 50 W of power b. 4.02 into a 75 ohms lossless coaxial cable. The c. 6.15 input impedance of the antenna at the feed d. 2.06 point is 300 ohms. How much power is 56. A lossless transmission line is connected to a radiated assuming unity gain, no coupling 10 ohms load. If the SWR = 5. Calculate the loss and the antenna is lossless? percentage of the incident power that is a. 56 w dissipated in the load. b. 87 w a. 89% c. 15 w b. 56% d. 32 w c. 15% 62. A properly terminated line has a line loss of d. 23% 1 dB/120m. If the power output of the 57. The reflection coefficient on a loss free line transmitter is 100 W, how much power of 72 ohms characteristic impedance is 60%. reached the load 30 m away? Calculate the load impedance (purely a. 12.21 w b. 94.41 w b. 56.2 MHz c. 26.18 w c. 4.4 MHz d. 110.12 w d. 10.215 MHz 63. The output power of the transmitter is 100 4. What power density is required to produce W. how strong must the signal be at the electric field strength of 100 volts per meter antenna if the antenna is connected to a in air? transmission line 50 meters long with a. 26.5 W/m2 reflection coefficient of 0.4 and an b. 56.23 W/m2 attenuation constant of 5 dB/100m? c. 14.20 W/m2 a. 47.23 w d. 15.12 W/m2 b. 15.12 w 5. If the critical frequency is 10 MHz in sky c. 7893.12w wave propagation, what is the best d. 154.01 w frequency to use assuming 30 degree of 64. A coaxial line having an impedance of 50 radiation angle? ohms is used in a cable TV system as drop a. 17 MHz cable. If the maximum line voltage are 15 V b. 15 MHz and 12 V minimum. What is the SWR of the c. 16 MHz line? d. 12 MHz a. 4.01 6. In sky wave propagation, what is the critical b. 1.24 frequency if the maximum number of free c. 5.23 electrons in a certain ionosphere later is 1.5 d. 1.25 x1012 per cubic meter? 65. An SWR meter is used to measure the a. 45 MHz degree of mismatch on the line. The SWR b. 79 MHz meter records 1.6 when the line is c. 16 MHz terminated with 50 ohms and 2.2 when the d. 11 MHz load is change to 176 ohms. What is the 7. In wave propagation, determine the characteristic impedance of the line? refractive index of an ionosphere layer with a. 90 ohms 100 x 106 free electrons per cubic meter at 5 b. 100 ohms MHz frequency. c. 80 ohms a. 1 d. 740 ohms b. 2 c. 0.3 d. 0.99 RADIO WAVE PROPAGATION 8. What is the resultant field strength between 1. How far away is the radio horizon of an waves travelling in different paths when the antenna 100 ft high? product of the antenna heights above the a. 14.14 miles reflecting plane is equal to half wavelength b. 5.23 miles times the total direct distance path between c. 144.15 miles the two antennas? d. 568.1 miles a. 1 V/m 2. What is the maximum line of sight distance b. 2 V/m between a paging antenna 250 ft. high and a c. 0 V/m pager receiver 3.5 ft of the ground? d. 3 V/m a. 26 miles 9. According to the Philippine Electronics b. 25 miles Code, the maximum accumulated c. 21 miles Permissible Dose of 68 years old man is? d. 23 miles a. 456rems 3. At a certain time, the MUF for transmissions b. 250rems at an angle of incidence of 75 degree is 17 c. 123rems MHZ. what is the critical frequency? d. 320rems a. 2.32 MHz 10. In a VHF mobile radio system, the base station transmits 100 W at 160 MHz substance at 100 meters at a time is to 140 frequency using half wave dipole antenna 20 meters to air? meters above ground. Calculate the field a. 2.2 strength at a receiving antenna at a height of b. 1.4 4 meters and a distance of 30 km. c. 15.2 a. 41.78uV/m d. 48.2 b. 12.02uV/m 17. Determine the critical frequency value of an c. 157.0uV/m HF signal if its maximum usable frequency d. 65.48uV/m is 7050.50 kHz at 35 degrees incidence. 11. What is the effective radiated power of a a. 12.22 MHz repeater with 450 W transmitting power b. 5.775 MHz output, 4 dB loss, 6 dB duplexer c. 124.255 MHz loss, and 7 dB circulator loss and feed line d. 789.02 MHz antenna gain of 25 dB? 18. Determine the effective radiated power of 20 a. 245.2 w kW TV broadcast transmitter whose antenna b. 1254.02 w has a field gain of 2. c. 2839.31 w a. 45kW d. 15.21 w b. 12kW 12. A microwave transmitting antenna is 600 c. 65kW feet high. The receive antenna is 240 feet d. 80kW high. The maximum transmission distance 19. What is the free space loss, in dB, between is? two microwave parabolic antennas 38 a. 23.22 m kilometer apart operating at 7 GHz? b. 15 m a. 140.89 dB c. 487.5m b. 12.02 dB d. 56.55 m c. 785.1 dB 13. As specified by the National Committee on d. 201.2 dB Radiation Protection Measurement (USA), 20. In sky wave propagation, if the critical what would be the maximum accumulated frequency is 25 MHz, what is the best permissible does to the whole body of a 50 frequency to use? Assume radiation angle of year old man? 45 degree. a. 160rems a. 23 MHz b. 125rems b. 45.2 MHz c. 14rems c. 30 MHz d. 102rems d. 25 MHz 14. The total power delivered to the radiator of 21. If the maximum number of free electrons in an isotropic antenna is 200,000 W. a certain ionosphere layer is 2 x 1012per m3, determine the power density at a distance of what is its critical frequency? 100 meters. a. 12.73 MHz a. 2 W/m2 b. 56.2 MHz b. 1.59 W/m2 c. 154.0 MHz c. 2 W/m2 d. 21.01 MHz d. 459 W/m2 22. What is the refractive index of an 15. Calculate the electric field intensity in mill ionosphere layer with 100 x 105 free volts per meter at 30 kW from a 5 km electrons per m3? Assume frequency to be at source. 20 MHz a. 189.74 mV/m a. 1 b. 456.20 mV/m b. 2 c. 14.21 mV/m c. 0.99 d. 158.0 mV/m d. 3 16. What is the index of refraction of a certain 23. If the velocity of propagation in a certain substance if a light travel through the medium is 200 x 106, what is its refractive index? c. 125789m a. 1.2 d. 99856m b. 1.5 29. Antenna heights of transmitting and c. 1.3 receiving antenna are found to be 20 meters d. 1.4 and 10 meters respectively. What is the 24. What is the propagation velocity of a signal maximum distance of the two antennas if in a transmission line whose inductance and troposphere transmission is used? capacitance are 5 micro H/m and 20 micro a. 12.21mi F/m respectively? b. 45.23mi a. 2.02 x 103 m/s c. 19.55 mi b. 236 x 103 m/s d. 65.2mi c. 145 x 103 m/s 30. The antenna is beam 30 degree above the d. 100 x 103 m/s ground for optimum transmission. 25. AGILA satellite is located 36000 km above Determine the transmission range, if the earth’s surface. Assuming free space ionosphere transmission is used and virtual condition what is the path loss of the signal height is 200 km. assuming, the earth is flat. if the operating frequency is 3 GHz? a. 89 km a. 193.07 db b. 458 km b. 23.2 db c. 564 km c. 489 db d. 693 km d. 1256.20 db 31. The antenna is beam 10 degree above the 26. A certain earth station transmitter output ground for optimum transmission. power is 10 kW, transmitting antenna gain Determine the transmission range, if 100 dBi, receiving antenna gain 75 dBi, ionosphere transmission is used and virtual uplink and downlink frequency of 2.4 GHz height is 200 km. and 2 GHz, respectively. What is the a. 1604 km received signal level at the satellite? b. 5986 km a. 12uW c. 2015 km b. 125uW d. 6453 km c. 45uW 32. The signal propagates in fresh water with an d. 7.71uW average conductivity of 2.5 S/m. determine 27. The two half wave dipole antennas are the attenuation coefficient if the relative positioned maximum transmission and permittivity of the medium is 65 and signal reception of signal. If the input power at the frequency is 3 kHz. feed point is 150 W, what is the voltage a. 172.02 x10-3Np/m induced at the feed point if the antennas are b. 45 x10-3Np/m spaced 1 km apart and operating at 126 c. 789 x10-3Np/m MHz? d. 15 x10-3Np/m a. 45.21 mV 33. A microwave radio link is installed on a hill b. 65.63 mV 100 m high above the ground. The link is 10 c. 12 mV km from the ground station, is set to d. 1254.2 mV transmit 10 W from a parabolic dish having e. a gain of 3000 over isotropic. Calculate the 28. A mobile radio system base station is signal strength received if the height of the installed 50 meters above the ground and ground station is 10 m operating frequency transmits 150 W at 54 MHz if the at 250 MHz. transmitting antenna gain is 5.17, how far a. 78.1 mV/m will the receiving antenna be, if the antenna b. 99.34 mV/m height is 30 m and the received field c. 45 mV/m strength is 22 micro V/m. d. 56.23 mV/m a. 153313 m 34. A VHF radio is to be established via the b. 25421m ionosphere. Assuming the earth is flat with the critical frequency of 5 MHz, the angle of is radiated from another lambda over 2 elevation is 45 degree. Calculate the dipole 100 km away. optimum working frequency. a. 119.32uV a. 8 MHz b. 45.25uV b. 5 MHz c. 78.2uV c. 6 MHz d. 89uV d. 56 MHz 2. For an antenna in a form of a linear 35. An unknown medium was used in conductor or an array of conductors communication system. If the characteristic calculate the effective length at 3 MHz. impedance of that medium is 150 ohms, a. 56.2 m what is the relative permittivity? b. 23.5 m a. 5.23 c. 31.83 m b. 20.51 d. 56.3 m c. 2.51 3. To minimize interference, a 500 MHz d. 2.54 dish needs to have a 1 degree beam 36. A shortwave transmitter uses sky wave width. What is the corresponding gain in propagation. What is the angle of incidence dB? if the MUF is 19 MHz and the critical a. 56 db frequency is 5 MHz? b. 45.2 db a. 45.2 c. 48.2 db b. 15.36 d. 44.7 db c. 74.7 4. A dish designed for operation at 150 d. 15.25 MHz is operated at twice that frequency. 37. What is the critical angle of the signal when By what factor do gain change? it passes from glass, with relative a. 5 permittivity of 7.8 into air? b. 4 a. 7.4 c. 3 b. 5.2 d. 2 c. 3.2 e. 1 d. 51.2 5. What is the power gain in dB of a 38. A TV broadcast station has a transmitting uniformly illuminated parabolic reflector antenna located 20 m above the ground. whose half power beam width is 3 What is the height above the ground of the degrees? receiving antenna 30 km from the a. 45.2 db transmitter? b. 33.5 db a. 4.5m c. 56.5 db b. 7.9m d. 783db c. 65.2m 6. In aperture antennas for microwave d. 15.25m communications, what is the aperture 39. What is the angle of incidence of the radio number if the angular aperture is 55 wave signal as it moves from air to glass, if degree? the angle of refraction is 8.2 degree? a. 0.48 a. 2.93 b. 5.2 b. 6.26 c. 48.2 c. 8.5 d. 12.2 d. 56.2 7. What is the effective area of a Hertzian ANTENNA dipole antenna for unity efficiency at 3 1. Two half wave dipole antennas are MHz? positioned for optimum transmission and a. 1190 m2 reception. Calculate the open circuit b. 236 m2 voltage induced in one lambda over 2 c. 486 m2 dipole when 20 W of power at 250 MHz d. 1154 m2 8. For an antenna in a form of a linear a. 45 conductor, what is the effe3ctive length b. 56 at 10.5 MHz? c. 135 a. 5.05 d. 270 b. 2.03 16. A 400 feet antenna is to be operated at c. 90.3 6200 kHz. What is the wavelength at this d. 9.09 frequency? 9. A certain antenna has a gain of 7 dB a. 48.39m with respect to an isotropic radiator. b. 45.26m What is the effective area if it operates at c. 23.56m 200 MHZ? d. 15.26m a. 0.897 m2 17. A microwave communications uses b. 12 m2 plane reflectors as passive repeaters. The c. 0.5 m2 diameter of the parabolic antenna is 18 d. 0.65 m2 feet while the effective area is 310 ft2. 10. Determine the gain of an antenna with Determine the reflector coupling factor. respect to a dipole if its gain with respect a. 0.5 to isotropic is 50 dBi. b. 0.6 a. 4.5 dB c. 0.9 b. 47.86 dB d. 0.91 c. 45.25 dB 18. A TVRO installation for use with a C- d. 96.2 dB band satellite has a diameter of about 3.5 11. If an antenna has a length of 0.125 meters and an efficiency of 60%. lambdas then what is the radiation Calculate its beam width. resistance? a. 4.2 a. 12.34 ohms b. 1.5 b. 78 ohms c. 2.3 c. 14.23 ohms d. 5.2 d. 56.2 ohms 19. A 500 kHz antenna radiates 500 W of 12. What is the horizontal beam width of a power. The same antenna produces field pyramidal horn antenna if its width is strength equal to 1.5 mV/m. if the power one wave length? delivered by the antenna is increased to a. 78 1 kW, what would be the expected field b. 23 intensity? c. 80 a. 2.12 mV/m d. 14 b. 45 mV/m 13. At 2 MHz, what is the effective area of c. 3.13 mV/m the Hertzian dipole for unity efficiency? d. 5.2 mV/m a. 2677.5 m2 20. What is the effective radiated power of a b. 45.25 m2 repeater with 250 W transmitting power c. 7855.2 m2 output, 3 dB feed line loss, 4 dB d. 5699 m2 duplexer loss, 5 dB circulator loss and 14. A helical has the following dimensions; feed line antenna gain of 20 dB? pitch is 1/3 wavelength; diameter is ¼ a. 456.2w wavelength and turns is 27. What is the b. 1577.61w gain in dB? c. 4599.2w a. 45.2 dB d. 7853.2w b. 5603 dB 21. What is the length in feet of an antenna c. 59.2 dB wire for 5 MHz if the antenna is 3.5 d. 19.2 dB waves in length? 15. What is the phase separation of two a. 688.8 ft antennas 3/8 wavelengths apart? b. 563.23 ft c. 865.23ft b. 24cm d. 485.21ft c. 45cm 22. If the antenna current increases 3.4 d. 78cm times, how much does the radiated 29. Determine the gain of a 6 ft parabolic power increase? dish operating at 1800 MHZ. a. 45.2 a. 45.12dB b. 11.56 b. 28.17dB c. 89.2 c. 12.5dB d. 4.2 d. 32.02dB 23. Determine the effective radiated power 30. A dipole antenna requires to be feed with of a transmitter if the input power to the 20 kW of power to produce a given final amplifier of 370 W with 60% signal strength to a particular distant efficiency if the field gain of the antenna point. If the addition of a reflector makes is 1.3, assuming 100% transmission line the same field strength available with an efficiency. input power of 11 kW. What is the gain a. 452.1 W in dB obtained by the use of the b. 123.2W reflector? c. 784.6W a. 8.5 dB d. 375.18W b. 4.6 dB 24. The transmitting antenna has a gain of c. 2.6 dB 10 dB, and power output of 6000 W. d. 1.6 dB determine the effective radiated power. 31. What is the gain, in dB of a helical a. 30000W antenna with diameter of lambda over 3, b. 40000W 10 turns at pitch of lambda over 4, used c. 50000W at 100 MHz? d. 60000W a. 18.2dB 25. What is the approximate length of a half b. 16.1dB wave dipole antenna radiating at 6450 c. 52.3dB kHz? d. 17.6dB a. 72.5 ft 32. The frequency of operation antenna cut b. 45.3ft to length of 3.4 m. c. 45.8ft a. 44.12 MHz d. 78.2 ft b. 45.2 MHz 26. Determine the approximate length of a c. 78.2 MHz simple whip quarter wave antenna at d. 56.8 MHz UHF frequency of 450.25 MHz. 33. What is the effective radiated power of a a. 0.35 ft repeater with 200 W transmitting power b. 0.15ft output, 2 dB feed line loss, 2 dB c. 0.89ft duplexer loss, and 3 dB circulator los d. 0.52ft and feed line antenna gain of 10 dB? 27. What is the length if a simple quarter a. 458 W wave antenna using a VHF frequency of b. 398W 150. 55 MHz? c. 896W a. 1.55 ft d. 126W b. 2.63ft 34. Determine the dB gain of a receiving c. 4.25ft antenna which delivers a microvolt d. 7.23ft antenna which delivers a microvolt 28. Find the approximate width of a signal to a transmission line over that of pyramidal horn antenna that will operate an antenna that delivers a 2 micro volt at 10000 MHz intended to have a beam signal under identical circumstances. width 10 degree. a. -7dB a. 26cm b. -8dB c. -9dB used to operate at a frequency of 1.2 d. -6dB GHz. What is the total length of the 35. The actual length of the Marconi antenna antenna? used in AM transmitter is 34 m. what is a. 75 cm the operating frequency of the b. 56cm transmitter, if the velocity factor is 0.9? c. 23cm a. 5.2 MHz d. 14cm b. 1.98 MHz 42. An earth satellite station needed an c. 4.2 MHz antenna that can amplify 2500 times d. 3.2 MHz bigger than the input signal. If the 36. What is the ohmic resistance of the engineers assigned agreed to build an antenna, if the efficiency of the antenna antenna with parabolic reflector, and is 0.96 and the radiation resistance is 72 operates at 3.4 GHz, what is its ohms? diameter? a. 1 a. 452 cm b. 2 b. 120cm c. 3 c. 180cm d. 4 d. 5620cm 37. What is the gain of a half wave dipole 43. Calculate the operating frequency of a antenna if the antenna has an efficiency half wave dipole if the actual length is of 92%? 3.5 meter. a. 4.2 a. 40.7MHz b. 1.3 b. 21.3 MHz c. 1.6 c. 56.2 MHz d. 1.51 d. 58.1 MHz 38. The output power of an FM transmitter 44. Calculate the actual length of a half is 25 W. if the gain of the antenna wave dipole operating at a frequency of referred to isotropic is 50, what is the 67.25 MHz. ERP of the antenna? a. 4.2m a. 85.23dBw b. 1.2m b. 45.23dBw c. 3.1m c. 89.5dBw d. 2.12m d. 28.83dBw 45. An antenna with a radiation resistance of 39. A satellite tracking device uses a helical 50 ohms and a loss resistance of 3 ohms antenna that is operating at 1.2 GHz. If receives 150 watts of power from a the optimum diameter of the antenna is 8 transmitter. How much power is radiated mc and 10 turns, what is the gain of the into space? antenna? a. 141.51W a. 42.13dB b. 235.21W b. 15.78dB c. 563.25W c. 15.6dB d. 612.35W d. 15.89dB 46. An antenna with a radiation resistance of 40. A helical shape antenna with eight turns 75 ohms and a loss resistance of 5 ohms, is used to track satellite that is operating receives a 150 watts of power from a at 1.2 Ghz. If the spacing for the transmitter. How much power is wasted? antennas is 10 cm, what is the beam a. 56.2w width of the antenna? b. 5.35w a. 28.9 c. 154.2w b. 56.2 d. 9.375w c. 65.3 47. What is the efficiency of the antenna if d. 21.3 the radiation resistance is 72 ohms and 41. A certain antenna with twelve turns is the loss resistance is 2 ohms? a. 89.2% What is the gain of the antenna if the b. 97.3% antenna efficiency is 85%? c. 56.2% a. 4256 d. 100% b. 4587 48. A half wave dipole with a gain of 2.14 c. 4567 dBi is fed, by means of lossless, matched d. 1546 line by a 25 watts transmitter. What is 54. A parabolic antenna used in the satellite the electric field strength of the signal earth station has a beam width of 3 measured 15 km from the antenna in free degree. Calculate the effective area of a space in the direction of maximum 3 m dish with an illumination efficiency radiation? of 0.7 at 3 GHz. a. 2.34 mV/m a. 5.95m2 b. 5.23 mV/m b. 6.95 m2 c. 4.56 mV/m c. 4.95 m2 d. 45.26 mV/m d. 8.95 m2 49. A transmitter supplied 125 watts of 55. The signal field strength 10 km from the power to an antenna with an efficiency Yagi antenna in the optimum direction is of 95%. What is the power density 12 mV/m, and 180 degrees from the measured at a distance of 30 km from optimum direction at the same distance the antenna in the direction of maximum the field strength is reduced to 2 mV/m. radiation? Assume the transmission line what is the front to back ratio of the is lossless and perfectly matched. antenna? a. 10.5nW/m2 a. 14.6dB b. 11.2nW/m2 b. 15.6dB c. 21.02nW/m2 c. 17.6dB d. 13.23nW/m2 d. 18.6dB 50. A dipole antenna is designed to have 56. A Yagi antenna must be fed with 5 kW 94% efficiency. Determine the EIRP of of power to produce the same field this antenna if it is fed by a 50 watts strength at a given point as that of a half transmitter. wave dipole antenna fed with 10 kW of a. 14.52dbw power. Determine the gain of the Yagi b. 16.72dbw antenna relative to isotropic. c. 15.72dbw a. 4.14dB d. 18.72dbw b. 3.14dB 51. Determine the actual length of a Marconi c. 5.14dB antenna operating at a frequency of 1625 d. 6.14dB kHz. 57. Two antennas are fed with equal power. a. 42.85m If the power density measured of the b. 41.85m antenna under test is 2 micro W/m2 and 8 c. 43.85m micro W/m2 for the standard antenna. d. 44.85m What is the gain of the antenna under 52. A parabolic antenna used in the satellite test referred to dipole if the gain of the earth station has a beam width of 3 standard antenna is 30 dBi? degree. If the antenna is operating at a a. 20.86 frequency of 14 GHz, what is the b. 19.86 minimum diameter of the antenna? c. 21.86 a. 0.5m d. 22.86 b. 0.6m 58. A Yagi antenna with front to back ratio c. 0.2m of 10 dB radiates power of 10 watts in d. 0.3m the opposite direction. Determine the 53. A parabolic antenna used in the satellite power output of the transmitter, if the earth station has beam width of 3 degree. gain of the antenna is 10 dBi? a. 8W is the gain of the antenna referred to b. 9W isotropic with the additional reflector? c. 1W a. 5.37dB d. 10W b. 6.37dB 59. The power radiated on a dipole is 2 W. if c. 98.37dB the input power to the antenna is 2.6 W d. 7.37dB and the current fed is 2 A, calculate the 65. An antenna wit parabolic dish reflector ohmic resistance of the dipole. has a beam width of 2 degrees and a gain a. 0.11 ohms of 30 dBi. Calculate the power density at b. 1.2 ohms a range of 5 km at an angel of 1 degree c. 0.16 ohms to the direction of maximum radiation if d. 0.15 ohms the power radiated is 1.8 W. 60. The power supplied to the antenna is 5 a. 5.86uW/m2 kW. If the efficiency of the dipole is 0.7, b. 2.86uW/m2 determine the power loss of the antenna. c. 9.86uW/m2 a. 2.5kW d. 4.86uW/m2 b. 3.2kW 66. A half wave dipole antenna is used to c. 6.1kW operate at 54 MHz. considering end d. 1.5kW effect, what is the effective area of the 61. A half wave dipole is designed to antenna? intercept maximum power at 300 MHz. a. 5.64 m2 calculate the effective aperture of a half b. 4.64 m2 wave dipole. c. 9.64 m2 a. 0.16 m2 d. 3.64m2 b. 0.13 m2 67. A helical antenna is used to track c. 0.12 m2 satellites in space. If the antenna consists d. 0.15m2 of 15 turns, spacing 15 cm, and diameter 62. A vertical whip antenna is located in 19.1 m, what is the operating frequency field strength of 7 mV/m. if the effective of the antenna to transmit the signal length of the antenna is 1 m. calculate efficiently? the voltage induced into the antenna. a. 500 MHz a. 7mV b. 400 MHz b. 5mV c. 300 MHz c. 6mV d. 200MHz d. 9mV 68. A satellite earth station uses an antenna 63. An aerial that is mounted vertically is with parabolic reflector that has a gain of operating at 3 MHz is 100 m high. It 30 dBi at 3.2 GHz. What is its gain if the carries a current that varies linearly from operating frequency is changed to 21.5 a maximum of 10 A at the base to 0 A to GHz, assuming the other parameters the top. Determine the effective height remain the same? of the aerial. a. 56.55dBi a. 200m b. 59.55dBi b. 300m c. 58.55dBi c. 100m d. 46.55dBi d. 400m 64. A half wave dipole requires to be fed NOISE with 10 kW of power to produce 2 1. The signal to noise ratio is 30 dB at the mV/m signal strength 5 km from the input to an amplifier and 27.3 dB at the antenna. The field strength is measured output. What is the noise temperature of again and the result is the same, but this the amplifier? time a reflector is added to the antenna a. 250.1K and the input power is only 3 kW. What b. 249.4K c. 249.5K d. 0.56uV d. 249.6K 8. Calculate the overall noise figure 2. A 3 stage amplifier has the following referred to the input of a mixer stage that power gains and noise figures for each has a noise figure if 15 dB preceded by stage; Stage 1, power gain = 10, noise an amplifier that has a noise figure of 6 figure = 3; stage 2, power gain = 20, dB and an available power gain of 20 dB noise figure = 4, stage 3, power gain = a. 6.32dB 30, noise figure = 5. Calculate the total b. 5.32dB noise figure. c. 9dB a. 5.1dB d. 4.32dB b. 5.2dB 9. What is the input equivalent signal to c. 5.3dB noise ratio for a receiver with a noise d. 5.4dB figure of 15 dB and an output signal 3. An amplifier operating over a 4 MHz noise to ratio 60 dB? bandwidth has a 100 ohms input a. 45dB resistance. It is operating 27 degree b. 65dB Celsius, has a voltage gain of 200 and c. 85dB has input signal of 5 micro Vrms. d. 75dB Determine rms output noise signal? 10. What is the noise level in a voice a. 512uV channel if the S/N is 71.25 dB? Express b. 514uV noise level in pWpO? c. 523uV a. 45 d. 515uV b. 12 4. Determine the noise current for a diode c. 46 with a forward bias of 1 mA over a 100 d. 42 kHz bandwidth? 11. If the occupied baseband of white noise a. 0.0057uA test signal is 60 – 4028 kHz. Determine b. 0.0056uA the bandwidth ratio. c. 0.0024uA a. 35.2dB d. 0.0051uA b. 31.07dB 5. A amplifier has a measured c. 38.1dB S/N power of 10 at its input and 5 at its d. 36.2dB output. Calculate the NF. 12. Calculate the equivalent noise a. 1 temperature of a receiver with a noise b. 2 figure of 1.5 dB. c. 3 a. 119.64K d. 4 b. 118.65K 6. Two resistors, 5 kilo ohms and 20 kilo c. 112.63K ohms are at 27 degree Celsius. Calculate d. 118.26K the thermal noise voltage for a 10 kHz 13. What is the overall signal to noise ratio bandwidth if they are in series. in dB of a tandem connection with the a. 2.031uV following individual signal to noise b. 2.056uV ratio. First stage = 10 dB; second stage = c. 2.045uV 15 dB and third stage = 20 dB? d. 2.035uV a. 5.84dB 7. Calculate the thermal noise voltage of b. 8.48dB the two resistors, 5 kilo ohms and 20 c. 5.98dB kilo ohms at 27 degree Celsius if they d. 5.12dB are connected in parallel. 14. If all the stages in a tandem circuit have a. 0.91uV identical signal to noise of 15 dB, then b. 0.54uV what is the overall signal to noise ratio in c. 0.81uV dB of the connection when there are 5 stages? for environmental temperature. a. 8.05dB a. 903 K b. 8.06dB b. 904 K c. 8.01dB c. 905 K d. 8.02dB d. 906 K 15. In psophometric noise measurement, 21. When measuring a voice channel dB test what is the psophometric noise power in point level, the meter reads -76 dBm. pWp if the psophometer reads 10 mV of Calculate the reading in dBrnCO. noise voltage? a. 15 a. 0.167x10-18 b. 16 b. 0.168x10-18 c. 17 c. 0.166x10-18 d. 18 d. 0.165x10-18 22. A diode generator is required to produce 16. Determine the effective noise 12 micro volts of noise in a receiver with temperature of an antenna system at the an input impedance of 75 ohms and a far end of the feed line if the effective noise power bandwidth of 200 kHz. sky noise temperature is 200 K and Determine the current through the diode antenna and feed line loss is 10. in milli amperes. a. 289K a. 398mA b. 288K b. 399mA c. 282K c. 400mA d. 281K d. 401mA 17. An amplifier operating over a 2 MHz 23. A 3 stage amplifier has stages with the bandwidth has an 80 ohms input following specifications; stage 1, power resistance. It is operating at 27 degree gain is 10, noise figure is 2; stage 2, Celsius, has a voltage gain of 200 and an power gain is 20, noise figure is 4, stage input signal of 6 micro Vrms. Calculate 3, power gain is 30, noise figure is 5. the output rms noise. Calculate the total noise figure of the a. 326.6uV system, assuming matched condition. b. 327.6uV a. 3.65dB c. 325.6uV b. 3.66dB d. 324.6uV c. 3.67dB 18. An amplifier operating over a 5 MHz d. 3.68dB bandwidth has a 100 ohm input resistance. It is operating at 27 degrees 24. 2 resistors rated 5 ohms and 10 ohms are Celsius, has a voltage gain of 200 and an connected in series and are at 27 degree input signal of 6 micro Vrms. Calculate Celsius. Calculate their combined the output rms noise. thermal noise voltage for a 10 kHz a. 573.5uV bandwidth. b. 574.5uV a. 0.04uV c. 575.5uV b. 0.05uV d. 576.5uV c. 0.06uV 19. A transistor amplifier has a measured d. 0.07uV S/N power of 100 at its input and 20 at 25. A transistor has a measured S/N power its output. Determine the noise figure of of 60 at its input and 19 at its output. the transistor. Determine the noise figure of the a. 6.99dB transistor. b. 6.09dB a. 2dB c. 6.9dB b. 3dB d. 6.89dB c. 4dB 20. Convert noise factor of 4.02 to d. 5dB equivalent noise temperature. Use 300 K 26. A transistor amplifier has a measured S/N power of 80 at its input and 25 at the will be? output. Determine the noise figure of the a. ½ transistor. b. 1/3 a. 5.04dB c. 2/3 b. 5.05dB d. 1/4 c. 5.06dB 32. Determine the shot noise for a diode d. 5.07dB with a forward bias of 1.40 mA over an 27. A satellite receiver has a noise figure of 80 kHz bandwidth. 1.6 dB. Find its equivalent noise a. 4.nA temperature. b. 5.nA a. 132.2K c. 6.nA b. 131.2K d. 7.nA c. 130.2K 33. Given a noise factor of 10, what is the d. 129.2K noise figure in dB? 28. An amplifier with an overall gain of 20 a. 5dB dB is impressed with a signal whose b. 10dB power level is 1 watt. Calculate the c. 15dB power output in dBm. d. 20dB a. 40dBm 34. Express the ratio in decibels of power b. 45dBm ratio 50 is to 10 Watts. c. 50dBm a. 6.59dB d. 55dBm b. 6.99dB 29. The signal power of the input to an c. 6.79dB amplifier is 100 micro W and the noise d. 6.89dB power is 1 microW. At the output, the 35. The resistor R1 and R2 are connected in signal power is 1 W and the noise power series at 300 degrees K and 400 degrees is 40 mW. What is the amplifier noise K temperature respectively. If R1 is 200 figure? ohms, and R2 is 300 ohms, find the a. 6.01dB power produced at the load over a b. 6.1dB bandwidth of 100 kHz. c. 6.02dB a. 0.497fw d. 6.2dB b. 0.496fw 30. A 3 stage amplifier is to have an overall c. 0.495fw noise temperature no greater than 70 d. .494fw degree K. the overall gain of the 36. If voltage change is equal to twice its amplifier is to be at least 45 dB. The original value, what is its corresponding amplifier is to be built by adding a low change in dB? noise first stage to an existing amplifier a. 4 with existing characteristics as follows; b. 5 stage 2 has 20 dB power gain; 3 dB c. 6 noise figure. Stage 3 has 15 dB power d. 7 gain and 6 dB noise figure that the first 37. A 20000 ohms resistor is at room stage can have. temperature. Calculate the threshold a. 0.56db noise voltage for a bandwidth of 100 b. 0.66db kHz. c. 0.76db a. 5.657uV d. 0.86db b. 5.658uV 31. What is the effect on the signal to noise c. 5.659uV ratio of a system if the bandwidth is d. 5.660uV doubled, considering all other 38. 3 amplifiers are cascaded together. parameters to remain unchanged except Determine the total noise figure in dB if the normal thermal noise only? The S/N the noise figure of each amplifier is equal to 3 dB and the amplifier gain is b. 2.7uV 10 dB each. c. 2.80uV a. 3.24dB d. 2.8uV b. 3.25dB 45. A diode noise generator produces 90 nA c. 3.26dB in a receiver with an input impedance of d. 3.27dB 75 ohms, resistive and a noise power 39. For an equivalent noise bandwidth of 10 bandwidth of 250 kHz. What must the MHz in a satellite system and a noise current through the diode be? power of 0.0280 pW, determine the a. 100.24mA noise density in dBW b. 101.24mA a. -205.56dBw c. 100.25mA b. -205.59dBw d. 101.25mA c. -205.50dBw 46. 2 resistors in series (R1 = 50 ohms; T1 = d. -205.53dBw 350 degree K) and (R2 = 100 ohms; T2 40. 2 resistors, 20 K ohms and 50 K ohms = 450 degree K). Determine the total are at ambient temperature. Calculate for noise voltage over a bandwidth of 120 a bandwidth equal to 100 kHz, the kHz. thermal noise voltage for the 2 resistors a. 543.4nV connected in parallel. b. 543.3nV a. 4.78uV c. 643.4nV b. 4.780uV d. 643.3nV c. 4.79uV 47. A certain company manufactures an AM d. 5.90uV receiver with a noise temperature of 450 41. A receiver connected to an antenna degree K. calculate the noise figure of whose resistance is 50 ohms has an the receiver. equivalent noise resistance of 30 ohms. a. 4.0dB What is the receiver’s noise b. 4.1dB temperature? c. 4.2dB a. 174.01K d. 4.3dB b. 174.1K 48. Calculate the noise temperature if the c. 174K input signal to noise ratio is 20 and the d. 175K output signal to noise ratio is 5. 42. The equivalent noise temperature of the a. 800K amplifier is 25 K. what is the noise b. 870K figure? c. 940K a. 0.36dB d. 1010K b. 0.41dB 49. Calculate the bias current of the diode of c. 0.46dB it produces 150 nA noise current over a d. 0.51dB 300 kHz bandwidth. 43. The signal in a channel is measured to be a. 234.1mA 23 dB while noise in the same channel is b. 234.01mA measured to be 9 dB. The signal to noise c. 234.2mA ratio therefore is? d. 234.02mA a. 14dB 50. Noise voltage at the input of an amplifier b. 28dB is 1 micro V. what is the signal voltage c. 42dB of the input signal to noise ratio is 20 d. 56dB dB. 44. Find the noise voltage applied to the a. 10uV receiver input if a 300 ohms resistor is b. 100uV connected in series to a 300 ohms c. 1000uV antenna of a television receiver. d. 10,000uV a. 2.70uV 51. A receiver has a noise power of 1 nW at the input of the receiver. What would be resistors connected in parallel. Given the signal power if the signal to noise that the temperature is 17 degree ratio is 40 dB? Celsius, and noise bandwidth of 15 a. 5uV MHz. b. 10uV a. 21.3uV c. 15uV b. 21.03uV d. 20uV c. 22.3uV 52. What would be the noise voltage d. 22.03uV generated of a 73 ohms resistor at room 58. The shot noise current on a diode is 25 temperature over the bandwidth of an nA if 2.5 mA direct current is flowing FM channel? thru it. What is the effective noise a. 452.nV bandwidth of the diode? b. 472.nV a. 781.24khz c. 492.nV b. 781.25khz d. 512.nV c. 782.24khz 53. A 3 stage amplifier in cascade has the d. 782.25khz following parameters. Stage 1 has a gain 59. A uses a single parallel of 5 and noise factor 2; stage 2 has a tuned circuit, designed to resonate at gain of 8 and noise factor 4; stage 3 has 1605 kHz. The Q factor of the receiver is again of 15 and a noise factor of 6. Find 50 and the channel bandwidth is limited the overall noise factor of the system. to 10 kHz. What is the noise voltage of a. 2.725 the receiver at the input at room b. 2.726 temperature if the capacitance of the c. 2.727 tuned circuit is 20 pF? d. 2.728 a. 0.9uV 54. What is the noise power of a resistor at b. 0.8uV room temperature with noise bandwidth c. 0.7uV of 2.5 MHz? d. 0.6.uV a. 10x10-15w 60. A mixer with input resistance of 300 b. 10x10-16w ohms has equivalent noise resistance of c. 10x10-17w 100 ohms. What is the noise voltage at d. 10x10-18w the input when the effective noise 55. What is the noise voltage given that R = bandwidth is 25 kHz, the source voltage 200 K ohms at a temperature of 27 is 2 micro V and with internal resistance degree Celsius and noise bandwidth of of 20 ohms? 54 MHz? a. 0.217uV a. 423.uV b. 0.218uV b. 424.uV c. 0.219uV c. 425.uV d. 0.220uV d. 426.uV 61. In a TVRO circuit the antenna is 56. Calculate the noise voltage generated by connected directly into the amplifier. To 5 kilo ohms, 10 kilo ohms and 15 kilo match the input impedance of the ohms, resistors connected in series. antenna and the 15 K ohms input Given that the temperature is 25 degree resistance of the amplifier a coupling Celsius, and noise bandwidth of 75 system is used with 10:1 ratio. The MHz. amplifier has an equivalent noise a. 192.4uV resistance of 150 kilo ohms. What is the b. 193.4uV noise voltage seen at the amplifiers input c. 194.4uV terminal? Given that the effective noise d. 195.4uV bandwidth is 20 kHz at room 57. Calculate the noise voltage generated by temperature. 3 kilo ohms, 10 kilo ohms, 21 kilo ohms, a. 7.0uV b. 7.1uV b. 44.9uv c. 7.2uV c. 44.10uV d. 7.3uV d. 44.11uV 62. A mixer with input resistance of 200 67. 4 telephone circuits are connected in ohms has an equivalent noise resistance tandem. What is the overall S?N ratio of of 100 ohms. What is the S/N at the each circuit has a S/N of 30 dB. input if the effective noise bandwidth is a. 12dB 25 kHz, a source voltage of 2 micro V b. 24dB and with internal resistance of 20 ohms? c. 36dB a. 18.46dB d. 48dB b. 18.47dB 68. What is the output S/N ratio if the noise c. 18.48dB factor is 20 and 25 dB input S/N ratio? d. 18.49dB a. 6324.56 63. What is the effective noise bandwidth of b. 6325.56 a parallel tuned circuit with 5 kilo ohms c. 6326.56 and 250 nF? d. 6327.56 a. 800hz 69. An AM receiver with RF amplifier, b. 600hz mixer and an AF amplifier has an overall c. 400hz noise figure of 60. The mixer has a noise d. 200hz factor of 20 and power gain of 30, and 64. What is the effective noise bandwidth of AF amplifier has noise factor and power a parallel resonant circuit that has a Q gain of 30 and 50 respectively. What is factor of 100 and resonant frequency of the noise factor of the RF amplifier if 5 MHz? their power gain is 50? a. 78.54khz a. 59.5 b. 78.55khz b. 59.6 c. 78.56khz c. 59.7 d. 78.57khz d. 59.8 65. A parallel tuned circuit with 20 pF 70. A TVRO parabolic dish reflector mixer tuning capacitor has an effective noise stage has a noise figure of 20 dB and is bandwidth of 15 kHz. What is the noise preceded by an LNB with a power gain voltage across the circuit at room of 10 dB and an equivalent noise temperature if the resonant frequency is temperature of 60 degree K. what is the 5 MHZ and a Q factor of 50? effective noise temperature at the input a. 4.4uV of LNB? b. 4.04uV a. 2921K c. 4.5uV b. 2931K d. 4.05uV c. 2941K 66. In a TVRO circuit the antenna is d. 2951K connected directly into the amplifier. To 71. In a microwave communications system, match the input impedance of the determine the noise power in dBm for an antenna and the 15 kilo ohms input equivalent noise bandwidth of 10 MHz. resistance of the amplifier a coupling a. -103.98dBm system is used. The amplifier has an b. -103.97dBm equivalent noise voltage of 7.1 micro V c. -103.96dBm at the input. Determine the antenna EMF d. -103.95dBm to produce an S/N of 30 dB if the transformer coupling has a turn’s ratio of 10:1. Given that the effective noise bandwidth is 20 kHz at room temperature. AMPLITUDE MODULATION a. 44.8uV 1. Determine the power saving in percent when the carrier is suppressed in an AM 7. A measure of steepness of the skirts or signal modulated to 80%. the skirt selectivity of a receiver is the a. 75.76% shape factor. What is the shape factor of b. 75.77% a receiver whose 60 dB bandwidth is 12 c. 75.78% kHz and a 6 dB bandwidth of 3 kHz? d. 75.79% a. 2 2. Find the percent of modulation of an AM b. 4 signal if 8 V signal carrier is modulated c. 6 by 3 different frequencies with d. 8 amplitude 1 V, 2 V and 3 V 8. A 200 V without modulation and 250 V a. 46.8% with modulation is measured across a 50 b. 46.9% ohms resistive load using true RMS c. 47.8% reading meter. What is the overall d. 47.9% efficiency without modulation if the 3. An SSB transmitter radiates 100 W in a transmitter draws 1 kW of power from 75 ohms load. The carrier signal is the ac line? modulated by 2 tones, with frequencies 2 a. 60% kHz and 3 kHz wit equal magnitude and b. 70% only the lower sideband is transmitted c. 80% with a suppressed carrier. What is the d. 90% peak voltage across the load? 9. An Am transmission of 3 kW is 100% a. 122.5V modulated. If it is transmitted as an SSB b. 122.6V signal, what would be the power c. 122.7V transmitted? d. 122.8V a. 500W 4. An AM transmitter delivers 100 W b. 1000W carrier powers, when the supplies deliver c. 1500W 10 A from a 15 V. what load impedance d. 2000W is required by this amplifier in order for 10. The dc power supply of an SB it to deliver the rated power? transmitter is 24 V. what is the average a. 1.24ohms power if the transmitter if on voice peaks b. 1.25ohms the current achieves a maximum of 9.3 c. 1.26ohms A? d. 1.27ohms a. 74.4W 5. In AM, what is the sideband power b. 74.5W percentage assuming 100% modulation c. 74.6W and with carrier total power of 100 W d. 74.7W and 150 W respectively. 11. An AM receiver is tuned to broadcast a. ½ station at 600 kHz. Calculate the image b. 1/3 rejection in dB, assuming that the input c. ¼ filter consists of one tuned circuit with a d. 2/3 Q of 40. 6. An AM receiver uses a double tuned IF a. 37.57dB transformer with coupling constant of b. 38.57dB 1.5 kc. the quality factor of the primary c. 39.57dB and secondary winding is 60 and 30 d. 40.57dB respectively. What is the bandwidth of 12. An SSB system transmits a peak the transformer if the IF is 455 MHz? envelope power of 100 W into a 75 a. 16.38khz ohms load. The carrier signal is b. 16.37khz modulated by two tones, with c. 16.36khz frequencies 2 kHz and 3 kHz with equal d. 16.35khz magnitude and only the lower sideband is transmitted with a suppressed carrier. the carrier signal? Determine the average power into the a. 31W load. b. 61W a. 25W c. 91W b. 50W d. 121W c. 75W 19. An IF transformer of a radio receiver d. 100W operates at 455 kHz. The primary circuit 13. In the SSB, determine the maximum has a Q of 50 and the secondary has a Q suppression of the unwanted sideband if of 40. Find the bandwidth using the the deviation from a perfect 90 degree optimum coupling factor. phase shift is 5 degree? a. 15.288khz a. 27.2dB b. 30.288khz b. 27.3dB c. 45.288khz c. 27.4dB d. 60.288khz d. 27.5dB 20. A spectrum analyzer is used ti measure 14. An AM transmitter has an output power the magnitude of a certain signal with of 100 W at no modulation with respect to its frequency. Suppose the efficiency of 60%. What will be the equipment shows a carrier at 12 dBm, output power with 97% modulation? with two sidebands 8 dB below the a. 147W carrier, what is the depth of modulation b. 148W of the signal? c. 149W a. 0.6 d. 150W b. 0.7 15. A standard AM receiver is tuned to a c. 0.8 station at 650 kHz. If the intermediate d. 0.9 frequency of the receiver is 455 kHz, 21. Determine the modulation index of the what is the image frequency? signal given the following parameters. a. 1550khz Emax = 10 Vp, Emin = 4 Vp. b. 1560khz a. 0.67 c. 1570khz b. 0.68 d. 1580khz c. 0.69 16. An AM signal has a carrier frequency of d. 0.70 400 MHz and amplitude if 5 Vp. It is 22. A DSB-SC system must suppress the modulated by a sinusoidal wave with carrier by 50 dB for its original value of frequency of 2 kHz and peak amplitude 10 W. To what value must the carrier be of 2 Vp. What are the lower and upper reduced? sideband frequencies? a. 0 a. 300.002mhz b. 0.1 b. 400.002mhz c. 1 c. 500.002mhz d. 2 d. 600.002mhz 23. An SSBSC signal is modulated with two 17. Given an audio power of 500 W which audio tones having frequencies of 1200 will modulate an RF amplifier to 50% and 2700 Hz. The receiver is mistuned modulation. Find the Dc power input. so that the BFO is at 2.9993 MHz. What a. 1000W will be the output frequencies of the b. 2000W detector if the signal is LSB and the IF c. 3000W of the receiver is 3 MHz? d. 4000W a. 350hz 18. A CB transmitter supplies a total power b. 700hz of 120 W to an aerial. Suppose the c. 1050hz carrier is amplitude modulated to a depth d. 1400hz of 80%, how much power is wasted by 24. A transistor has a power dissipation rating of 30 W. assuming that the microV signal on the channel to which transistor is the only element that the receiver is tuned. Calculate the dissipated power in the circuit, calculate adjacent channel selectivity in dB. the power an amplifier, using this a. 212dB transistor, could deliver the load if it b. 159dB operates as class A with an efficiency of c. 106dB 30%. d. 53dB a. 12.86W 30. A 300 V without modulation and 350 V b. 12.85W with modulation are measure across a 50 c. 12.84W ohms resistive load using true RMS d. 12.83W reading meter. What is the amount of 25. An Am signal supplies 150 W of carrier power supplied in the transmitter when power when it is modulated by a single modulated if the efficiency os 60%. sine wave to a depth of 70%. Suppose a. 4083.33W the total transmitted power increases by b. 8083.33W 10% when another sine wave c. 12,083.33W simultaneously amplitude modulates the d. 16,083.33W carrier, determine the modulation index 31. A transistor RF amplifier is required to of the second sine wave. produce 15 W of carrier power when a. 0.5 operating from a 12 V supply. What is b. 0.4 the load impedance as seen from the c. 0.3 collector? d. 0.2 a. 16.8ohms 26. What rms current must a wire carry to b. 12.8ohms deliver an average power if 500 W to a 4 c. 8.8ohms ohm loudspeaker? d. 4.8ohms a. 9.18A 32. The output of a power amplifier if an b. 10.18A AM transmitter is 50 W with an c. 11.18A efficiency of 60% and is collector d. 12.18A modulated. How much audio power is 27. A superheterodyne receiver has an IF of required to be supplied to this stage for 455 kHz and is experiencing image 100% modulation? channel interference on a frequency of a. 42.65W 1570 kHz. The receiver is tuned to? b. 41.65W a. 200khz c. 40.65W b. 400khz d. 39.65W c. 600khz 33. The values of Vmax and Vmin as read d. 800khz from an AM wave on an oscilloscope are 28. An AM transmitter with a 100 kW 2.6 and 0.29 respectively. Determine the carrier transmits 123 kW when two tones percentage modulation. modulated. Calculate the modulation a. 79.9% index of the second sine wave if the total b. 69.9% transmitted power is 110 when c. 59.9% modulated by a single sine wave. d. 49.9% a. 0.545 34. A 3 stages RF amplifier of an AM b. 0.546 transmitter has an output power of 25 c. 0.547 kW. What is the power supplied at the d. 0.548 second stage if the gain of the last stage 29. When measuring the selectivity of a is 10 dB? receiver, you discover that a signal level a. 2.5W of 450 microV on an adjacent channel is b. 5W required to give the same output as 1 c. 7.5W d. 10W efficiency of 75%, how much current 35. An AM transmitter supplies a 10 kW of does the amplifier draw from a 125 V carrier power to a 50 ohms load. It supply? operates at a carrier frequency of 1.2 a. 160mA MHz and is 85% modulated by a 3 MHz b. 320mA sine wave. Calculate the RMS voltage of c. 480mA the signal. d. 640mA a. 825V 41. A receiver has two uncoupled tuned b. 1650V circuits before the mixer, each with a Q c. 2475V of 75. The signal frequency is 100.1 d. 3300V MHz and IF is 10.7 MHz. if the local 36. An AM signal has a modulation carrier oscillator uses high side injection, what power if 10 watts. The percentage of is the image rejection ratio on dB? modulation is 90%. The total sideband a. 29.33dB power is? b. 29.66dB a. 4.05W c. 29.99dB b. 4.06W d. 30.33dB c. 4.07W 42. An amplitude signal has a maximum d. 4.08W positive envelope voltage of 14 V and a 37. A class C amplifier has a carrier output minimum of 2 V. what is the total power of 100 W and an efficiency of transmitted power if the carrier power is 75%, when operating from a 20 V 10 kW and suppressing one of the supply. If the audio power is 25 W, what sidebands? is the impedance seen looking into the a. 10.41kW power amplifier from the modulation b. 11.41kW transformer secondary? c. 12.41kW a. 8 d. 13.41kW b. 16 43. The average collector current of a c. 24 transistor RF amplifier operating class C d. 32 is 250 mA. If the efficiency of the 38. An AM signal has the following amplifier is 50% and operating at 50 V characteristics; carrier frequency = 150 supply, how much audio power is MHz; modulating frequency = 3 MHz; needed for 100% modulation? peak carrier voltage = 40 V and peak a. 3.25W modulation voltage = 30 V. calculate the b. 6.25W peak voltage of the lower sideband c. 9.25W frequency. d. 12.25W a. 15V 44. A radio transmitter has to operate at a b. 30V temperature of 34 degrees Celsius. If its c. 45V signal is derived from a crystal oscillator d. 60V with a temperature coefficient of plus 1 39. An AM signal has a carrier frequency of pm per degree centigrade and it 3 MHz and amplitude of 3 Vpeak. What transmits at exactly 150 MHz at 20 is the amplitude of the sidebands if the degrees centigrade, find the transmitting modulation index is 0.6? frequency. a. 0.9V a. 150.0021 MHz b. 1.0V b. 160.0021 MHz c. 1.1V c. 170.0021 MHz d. 1.2V d. 180.0021 MHz 40. An Am transmitter has an output power 45. A standard AM radio can receive signal of 30 kW. If the last stage of the RF from 565 – 1650 kHz. If an AM receiver amplifier has a gain of 20 dB and an is tuned at 854 kHz, what is the frequency of the image signal? a. 62.5W a. 1564 kHz b. 26.3W b. 2356 kHz c. 59.2W c. 1764 kHz d. 12.2W d. 1587 kHz 52. What is the range of the upper sideband 46. An AM transmitter is modulated by two of an amplitude modulated signal whose sine waves at 1.5 kHz and 2.5 kHz, with carrier is 2.5 MHz and the intelligence modulations of 20% and 80% component is 50 Hz to 20 kHz? respectively. Calculate the effective a. 5.23 MHz modulation index. b. 2.52 MHz a. 0.26 c. 23.2 MHz b. 0.45 d. 1.23MHz c. 0.84 53. An SSB transmitter generates USB d. 0.82 signal with Vpeak = 10 V. determine the 47. Calculate the power in one sideband of peak envelope power across a 50 ohms an AM signal whose carrier power is 50 load resistance. watts. The unmodulated current is 2 A a. 1W while the modulated current is 2.4 A b. 2W a. 15W c. 3W b. 14W d. 7W c. 16W 54. CB radio wave signal is developed using d. 11 W a full carrier DSB-AM. For high fidelity, 48. An AM broadcast transmitter has a the system requires a frequency response sideband power output of 5 kW. from 50 Hz to 15 kHz. What bandwidth Calculate the carrier power if the would it used to satisfy the requirement? modulation index is 0.5. a. 35 kHz a. 45kW b. 32 kHz b. 40kW c. 30 kHz c. 56kW d. 31kHz d. 52kW 55. The frequency response of an audio 49. If a supplies 8 kW to the signal that amplitude modulates the antenna when it is unmodulated, carrier signal is 6 dB down at 2.5 kHz determine the total radiated power when deom its level at 1.25 kHz. What will be modulated at 30%. the modulation index due to a 2.5 kHz a. 8.36kW signal with the same signal at the input, b. 5.23kW if a 1.25 kHz signal modulates the c. 8.21kW carrier to 85%? d. 2.56kW a. 0.236 50. An LC tuned circuit is used to detect an b. 0.425 AM radio frequency band ranging from c. 12.033 535 to 1695 kHz. What us the bandwidth d. 0.569 at 1695, if its bandwidth is 12 kHz at 56. In an AM transmitter, the final RF power 535 kHz? amplifier is high level modulated. The a. 45.65 kHz dc supply voltage is 48 V with a total b. 34.21 kHz current of 3.5 A. how much AF power is c. 21.36 kHz required for 100% modulation? d. 56.23kHz a. 48W 51. A class C collector modulated amplifier b. 84W has an output carrier power of 100 W c. 56W and an efficiency of 80%. How much d. 23W audio power must be supplied to the 57. An AM transmitter supplies of 20 kW of amplifier for 100% modulation? carrier power to a 75 ohms load. Calculate the maximum instantaneous 80% modulation? voltage the will be developed across the a. 45W load. b. 46W a. 1546V c. 48W b. 5642V d. 12W c. 1722V 64. A filter type SSB generator uses an ideal d. 1732V band pass filter with a center frequency 58. What is the peak envelope power of a of 5 MHz and a bandwidth of 2.7 kHz. SSB transmitter that produces a peak to What frequency should be used for the peak voltage of 178 V across a 75 ohms carrier oscillator if the generator is to antenna load? produce a USB signal with a baseband a. 56.2W frequency response having a lower limit b. 52.8W of 280 Hz? c. 62.5W a. 4.99837 MHz d. 63.2W b. 5.23154 MHz 59. What oscillator frequency is needed to c. 3.21548 MHz heterodyne 626 kHZ up to 3.58 MHz? d. 7.26456 MHz a. 4.206 MHz 65. What will be the total sideband power of b. 2.036 MHz the AM transmitting station whose c. 5.021 MHz carrier power is 1200 W and a d. 3.021MHz modulation of 95%? 60. An SSB system requires 100 W of a. 125.2W transmitted power fir reliable b. 541.5W transmission. How much power is c. 154.2W needed if DSBFC is used instead of d. 985.02W SSB? 66. An AM signal has a carrier frequency of a. 500W 115 MHz modulated by a single sine b. 600W wave. The modulated signal developed a c. 700W maximum positive envelope voltage of 8 d. 800W V and a minimum of 2 V. what is the 61. A carrier signal simultaneously magnitude of the peak voltage of the modulated by two sine waves at 1.5 kHz unmodulated carrier? and 0.8 kHz with modulation index 0.3 a. 1V and 0.6 respectively. Calculate the total b. 2V modulation index. c. 3V a. 0.32 d. 5V b. 0.67 67. A transistor RF power amplifier c. 0.25 operating class C is designed to produce d. 0.87 40 W output with a supply voltage of 60 62. A CB transmitter supplies a total power V. if the efficiency is 70% what is the of 200 W to an aerial. Supposed the average collector current? carrier is modulated to a depth of 70% a. 952.4mA using DSBFC AM. By how much will b. 895.3mA the signal to noise ratio be improved if c. 784.6mA the modulation technique used is SSB d. 896.2mA instead of DSBFC AM? 68. A radio technician measure 350 V a. 10dB without modulation and 400 V with b. 11dB modulation at the output of an AM c. 12dB transmitter with 50 ohms resistive load d. 13dB using true RMS reading meter. What is 63. What is the power in one sideband of an the modulation index of the signal? AM signal whose carrier is 300 W, with a. 0.56 b. 0.78 modulation. The RF power amplifier c. 0.65 draws 12 A from a 22 V supply, putting d. 0.98 out a carrier power of 140 watts. What 69. A certain station is tuned a impedance would be seen at the t200 kHz with an image frequency at modulation transformer secondary? 460 kHz. Determine the intermediate a. 1.23 ohms frequency of the receiver. b. 1.83 ohms a. 150 kHz c. 1.56 ohms b. 140 kHz d. 1.82ohms c. 130 kHz 76. Calculate the highest and lowest d. 160kHz frequencies for a sub carrier signal at 70. What is the local oscillator frequency 629 kHz with bandwidth of + or – 500 range in commercial AM broadcast if it kHz. is equal to 455 kHz? a. 126 kHz a. 2055 kHz b. 125 kHz b. 2065 kHz c. 124 kHz c. 2045 kHz d. 129 kHz d. 2068 kHz 77. A tuned transformer has a kopt = 1.5 kc 71. A super heterodyne receiver tunes at the operating at a frequency of 455 kHz. The frequency range from 25 to 50 MHz. primary of Q is 75. What is the band what is the IF frequency of the receiver width of the tuned transformer? if the range of the local oscillator is 10 a. 13.3 kHz MHz to 35 MHz. b. 14.5 kHz a. 16 MHz c. 12.5 kHz b. 15 MHz d. 16.3 kHz c. 14 MHz 78. A 12 W of power is being supplied in the d. 13MHz modulating amplifier for 100% 72. A receiver has a sensitivity of 0.5 micro modulation. What is the carrier power V and a blocking dynamic range of 70 output of the radio transmitter at an dB. What is the strongest signal that can efficiency of 75%? be present along with a 0.5 micro V a. 15W signal without blocking taking place? b. 18W a. 1.56mV c. 19W b. 1.53mV d. 20W c. 1.54mV 79. A transmitted signal 5 meters in d. 1.58mV wavelength is received by an antenna 73. A receiver can handle a maximum signal coil having a 50 ohm resistance and a level of 100 mV without overloading is 0.01 H inductance. What is the 100 dB, what is the sensitivity of the capacitance of the tuner shunting the receiver? antenna coil at this point? a. 1uV a. 0.704fF b. 2uV b. 0.705fF c. 3uV c. 0.506fF d. 4uV d. 0.404fF 74. What is the shape factor of the filter if 80. Assuming 100% modulation, what 10 kHz bandwidth is measured below 6 would be the transmitted power in the dB and 30 kHz below 60 dB? upper sideband of an AM signal if the a. 3 carrier power is 1000 watts? b. 4 a. 150W c. 5 b. 250W d. 6 c. 650W 75. An AM transmitter uses high level d. 350W 81. A certain radio transmitter has a carrier a. 16V power output of 150 W and an efficiency b. 15V of 80%. How much power is dissipated c. 12V in the transistor with 80% modulation? d. 13V a. 50W 87. The average collector current of a b. 56W transistor RF amplifier operating class C c. 49.3W is 250 mA. If the efficiency of the d. 49.5W amplifier is 60% and operating at 50 V 82. An AM transmitter uses a high level supply, what is the power output of the modulation. The RF power amplifier amplifier? runs from a 12 V source, putting out a a. 5.5W carrier power of 85 W, with an efficiency b. 6.5W of 85%, what load impedance is required c. 7.5W in order for it to deliver the rated power? d. 8.5W a. 0.85 88. An AM transmitter is rated 100 W at b. 0.84 100% modulation. How much power c. 0.86 required for the carrier? d. 0.89 a. 66.67W 83. An AM mobile transmitter supplies 5 b. 55.57W kW of carrier power to a 50 ohms load. c. 44.57W The carrier signal is modulated by a 3 d. 99.67W kHz sine wave to a depth of 80% at a 89. An AM mobile transmitter supplies 5 frequency of 10 MHz. determine the kW of carrier power to a 50 ohms load. sideband power. The carrier signal is modulated by a 3 a. 1600W kHz sine wave to a depth of 80% at a b. 1200W frequency of 10 MHz. Determine the c. 1500W peak voltage of the modulating signal. d. 1800W a. 548.2V 84. If the percentage modulation of an AM b. 548.7V amplifier is 88% and the modulating c. 565.7V signal is 1 V, the carrier has amplitude d. 585.1V of? 90. An AM signal has a carrier frequency of a. 1.12V 3 MHz and amplitude of 2 Vpeak. What b. 1.13V is the sideband frequency if the c. 1.15V bandwidth of the AM signal is 20 kHz? d. 1.14V a. 3.02 MHz 85. An AM receiver uses a low side b. 5.23 MHz injection for the locas oscillator, with an c. 1.25 MHz IF of 455 kHz. The local oscillator is d. 6.31 MHz operating at 2.1 MHz. What is th e IF of 91. At 100% modulation, the sum of the the signal? effective voltages in both sidebands is a. 1.645 MHz equal to? b. 1.256 MHz a. 50.2% c. 1.459 MHz b. 60.2% d. 1.256MHz c. 70.7% 86. An AM signal has the following d. 80.5% characteristics, the carrier frequency is 92. An AM transmitter transmits 40 kW with 150 MHz, the modulating signal no modulation. How much power will it frequency is 3 kHz, the carrier voltage is transmit if modulation index increases 60 V, and where the modulating signal by 80%? voltage is 30 V. find the peak voltage of a. 52.8kW the lower side frequency. b. 56.2kW c. 53.8kW MHz. the receiver is mistuned causes the d. 54.6kW BFO to generate 2.995 MHz. Determine 93. 100% modulation in AM means a the output frequencies of the corresponding increase in total power demodulator if the signal is USB. by? a. 200 and 700 Hz a. 60% b. 300 and 800 Hz b. 70% c. 400 and 900 Hz c. 50% d. 500 and 1000Hz d. 80% 99. 3 audio waves with 100, 200 and 300 V 94. An AM transmitter delivers 100 W amplitude respectively, simultaneously carrier powers, when the supplies deliver modulate a 450 V carrier. What is the 8 A from a 15 V. how much power must total percent of modulation of the AM be supplied by the modulating amplifier wave? 85% modulation? a. 86% a. 45W b. 85% b. 23.5W c. 84% c. 12.4W d. 83% d. 43.35W 100. An AM broadcast transmitter output 95. A collector modulated class C amplifier power is 15 kW if the carrier is has a carrier output power of 100 W, and simultaneously modulated with another with an efficiency of 60%, calculate the sine wave at 50% modulation. What is transistor power dissipation, assuming the modulation index of the other sine that all the power dissipation that occurs wave if the carrier power is 12 kW? comes from the transistor. a. 0.5 a. 66.67W b. 0.2 b. 65.63W c. 0.6 c. 689.23W d. 0.4 d. 68.32W 101. What is the maximum suppression 96. An AM transmitter transmits 40 kW with for a phase error of 3 degree? no modulation. How much power will it a. 31.64dB transmit if modulation index is 80%? b. 31.65dB a. 52.8kW c. 31.62dB b. 52.3kW d. 31.52dB c. 52.4kW d. 52.9kW 97. A filter type SSB generator uses an ideal band pass filter wit h a center frequency of 5 MHz and a bandwidth of 2.7 kHz. What frequency should be used for the carrier oscillator if the generator is to produce a USB signal with a baseband frequency response having a lower limit of 280 Hz? a. 4552.35 kHz b. 4998.37 kHz c. 4557.65 kHz d. 4875.56kHz 98. The voice signal is modulated using a FREQUENCY MODULATION SSBSC technique with two audio tones having frequencies of 700 and 1200 Hz. The modulated signal has a suppressed 1. Using Carson’s rule, what is the carrier frequency in the IF receiver of 3 bandwidth of an FM signal with 5 kHz maximum frequency deviation sine-wave modulated? and 2.5 kHz maximum modulating a. 0.25V frequency? b. 0.23V a. 14 kHz c. 0.24V b. 16 kHz d. 0.26V c. 18 kHz 8. A phase-locked loop has a VCO with d. 15kHz free-running frequency of 19 MHz. 2. Calculate the maximum bandwidth as the frequency of the reference required of a standard FM broadcast input is gradually raised from zero, station. the loop locks at 8 MHz and comes a. 156 kHz out of lock again at 14 MHz. b. 180 kHz determine the lock range. c. 154 kHz a. 5 MHz d. 160 kHz b. 6 MHz 3. The operating frequency of an FM c. 8 MHz transmitter is 168.96 MHz. calculate d. 9 MHz the frequency of the carrier crystal 9. A phase modulator has kp = 2rad/V. oscillator if it uses three frequency what rms voltage of a sine wave multipliers – a doubler, a tripler and would cause a peak phase deviation a quadrupler. of 30 degrees? a. 7.04 MHz a. 0.184V b. 7.05 MHz b. 0.156V c. 7.06 MHz c. 0.187V d. 7.07MHz d. 0.185V 4. What frequency deviation is caused 10. A system uses a deviation of 100 by noise in an FM receiver which kHz and a modulating frequency of has an input S/N of 2.8 and the 15 kHz. What is the approximate modulating frequency of 1.5 kHz? bandwidth? a. 569.2Hz a. 235 kHz b. 587.3Hz b. 234 kHz c. 547.8Hz c. 230 kHz d. 569.2Hz d. 236kHz 11. A phase-locked loop has a VCO with 5. In GM broadcasting, what is the a free-running frequency of 14 MHz. carrier frequency in MHz of a station as the frequency of the reference with a channel number of 285? input is gradually raised from zero. a. 104.9 MHz The loop locks at 12 MHz and comes b. 104 MHz out of lock again at 18 MHz. c. 8 MHz calculate the capture range. d. 104.5 MHz a. 4 MHz 6. In FM broadcasting, what is the b. 5 MHz channel number of the station with a c. 6 MHz given carrier of 99.1 MHz? d. 7MHz a. 254 12. What is the frequency swing of an b. 259 FM broadcast transmitter when c. 258 modulated 80%? d. 256 a. 60 kHz 7. What is the rms output voltage of a b. 62 kHz PLL FM detector if it uses VCO with c. 63 kHz proportionality constant of 299 d. 64kHz kHz/V and if it receives an FM 13. Determine the modulation index of a signal with a deviation of 65 kHz standard FM broadcast having a hypothetical maximum carrier oscillator operate? frequency deviation of +- 12 kHz a. 10 MHz and a maximum modulating frequency of 4 kHz. b. 11 MHz a. 5 c. 12 MHz b. 4 c. 3 d. 13MHz d. 2 18. For commercial FM broadcasting the 14. What is the modulation index of an maximum permissible range in FM transmitter whose frequency modulation index is 5 – 2500. What deviation is 50 kHz, while its audio is the maximum bandwidth needed frequency is 10 kHz? for this system? a. 8 a. 180 kHz b. 6 b. 190 kHz c. 7 c. 200 kHz d. 5 d. 210kHz 15. The carrier swing necessary to 19. A portable radio transmitter has to provide 80% modulation in the FM operate at temperatures from – 5 broadcasting band is ____? degrees to 35 degrees C. if its signal a. 120 kHz is derived from a crystal oscillator b. 130 kHz with a temperature coefficient of +1 c. 140 kHz ppm per degree centigrade, and it d. 150 kHz transmit at exactly 145 MHz at 20 16. An FM signal has a center frequency degrees C, find the transmitting of 100 MHz but is swinging between frequency at 35 degrees C. 100.01 MHz and 99.999 MHz at a a. 145.002175 MHz rate of 100 times per second, what is b. 145.002174 MHz the modulation index of the signal? c. 145.002176 MHz a. 110 d. 145.002154MHz b. 100 20. What FM channel is 107.5 MHz c. 90 carrier? d. 80 a. 299 17. If the frequency fed to the pre- b. 298 amplifier of a basic transmitter with c. 297 multipliers is composed of a pair of d. 296 triples and a doublers multipliers is 21. The instantaneous value of the 198 MHz. what frequency should the modulating signal to and FM modulator is -2V, sensitivity kf = 25 modulating frequency of 300 Hz. kHz/V and operating at a carrier What is the maximum frequency frequency of 88 MHz. determine the deviation of the system? output frequency of the modulator. a. 315 Hz a. 87.59 MHz b. 314 Hz b. 95.32 MHz c. 316 Hz c. 87.95 MHz d. 317Hz d. 84.65 MHz 26. An FM communication system has a 22. Calculate the frequency deviation of sensitivity of kf = 3 kHz/V. how

an Fm modulator that has kf = 20 much phase deviation does it kHz/V and operates at a carrier produces with a sine wave input of 3 frequency of 99.1 MHz modulated V peak at a frequency of 2 kHz?

by a 2.5 Vrms sine wave. a. 4.2rad a. 70.5 kHz b. 4.5rad b. 70.6 kHz c. 4.3rad c. 70.7 kHz d. 4.8rad d. 70.8kHz 27. An FM broadcast transmitter rated 23. Find the deviation ratio of an FM output power is 5 W. what is the broadcast transmitter if the frequency peak voltage developed across a 50 of the modulating signal varies from ohms resistive load? 30 Hz to 20 kHz. a. 22.34V a. 3.75 b. 22.35V b. 3.74 c. 22.36V c. 3.73 d. 22.37V d. 3.72 28. An FM system has a modulation 24. The output signal of a PM index of 3 and its corresponding

demodulator is 0.54 V. what is the Bessel coefficient; Jo = -0.26; J1 =

sensitivity of the demodulator if the 0.34; J2 = 0.49; J3 = 0.31. Find the phase deviation is 30o? RMS carrier voltage if the total a. 0.99rad/V power is 5 W. developed across a 50 b. 0.98rad/V ohms resistive load. c. 0.97rad/V a. 4.16V d. 0.96rad/V b. 4.11V 25. A PM transmitter produces a c. 4.23V maximum phase shift of r/3 rad for a d. 4.56V 29. Suppose the total power of an FM a. 2 signal is 7W. What is the power of b. 3 the second sideband if the c. 5

modulation index is 3? J0 = -0.26; J1 d. 4

= 0.34; J2 = 0.49; J3 = 0.31. 33. An FM signal with modulation index a. 3.4W of 4 and modulating frequency of 8 b. 3.5W kHz. What is the frequency deviation c. 3.6W of the signal? d. 3.2W a. 36 kHz 30. An FM broadcast transmitter has a b. 35 kHz deviation of 25 kHz and a c. 31 kHz modulating frequency of 8 kHz. d. 32kHz Calculate the power that is 34. A certain FM modulator has kf = 25

unaccounted, if the total power PT is kHz/V. Suppose the peak amplitude

10 W. J0 = -0.26; J1 = 0.34; J2 = 0.49; of the modulating signal is 3 V at a

J3 = 0.31. frequency of 3 kHz, determine the a. 0.289W modulation index of the signal. b. 0.288W a. 25 c. 0.283W b. 26 d. 0.254W c. 27 31. A certain FM station transmitted a d. 28 modulating frequency of 25 kHz and 35. The output frequency of the a frequency deviation of 75 kHz. modulator increases by 50 kHz. What is the approximate signal-to- What is the dc voltage applied to the noise ratio at the detector output if FM modulator, if the deviation the signal-to-noise ratio at the input sensitivity is 25 kHz/V? to the receiver detector is 20 dB? a. 5V a. 34dB b. 4V b. 35dB c. 3V c. 36dB d. 2V d. 37dB 36. The maximum instantaneous 32. An FM broadcast station transmits a frequency of the modulated signal is 3 kHz test tone, and a frequency 95.05 MHz. if a 5 kHz signal deviation of 15 kHz. Determine the modulates a 95 MHz carrier, modulation index. calculate the modulation index of the signal. b. 300mV a. 10 c. 220mV b. 1 d. 100mV c. 11 40. With a maximum frequency d. 12 deviation of 75 kHz, what is the 37. A PM signal has a RMS signal of 3 maximum phase deviation that can V at a frequency of 3 kHz. If the be present in an FM radio broadcast modulation index of the signal is 15, signal, assuming it transmits a determine the sensitivity of the baseband frequency of 50 Hz to 20 modulator. kHz? a. 3.54rad/V a. 1560rad b. 3.53rad/V b. 1500rad c. 3.55rad/V c. 1540rad d. 3.52rad/V d. 1546rad 38. The modulation index of the PM 41. The phase shift of a phase modulated signal is 2. If a modulating signal signal is 86 degree. What is the that has amplitude of 50 mV at a modulation index of the said signal? frequency of 3 kHz phase modulates a. 1.2 a 90 kHz carrier signal, what would b. 1.5 be the new modulation index of the c. 1.3 signal? Assume that the amplitude of d. 1.6 the modulating signal is increased by 42. Determine the modulation index of 50%. an FM signal, given that the a. 5 modulating frequency is 25 kHz and b. 4 frequency deviation of 75 kHz. c. 3 a. 3 d. 2 b. 5 39. A sine wave of frequency 15 kHz c. 4 modulates a carrier at 101.1 MHz. d. 6 the peak frequency deviation is 75 43. Suppose a certain FM signal uses a kHz. Determine the peak amplitude frequency deviation of 100 kHz and of the modulating signal if the a modulating index of 5. Calculate sensitivity of the modulator is 50 the band width using Carsons rule. rad/V. a. 250kHz a. 40mV b. 240kHz c. 260kHz only the carrier and the first two sets d. 230kHz of sidebands. If the total power of the 44. An FM station transmits 100 W of signal is 10 W, deviation is 25 kHz, power. If the modulation index of the and the modulation index is 10, how signal is 7, how much power is much power is transmitted at the transmitted at the carrier frequency if carrier frequency? Jo = 0.4? a. 485mW a. 16W b. 484mW b. 17W c. 456mW c. 18W d. 481mW d. 19W 48. The calculated bandwidth using 45. A 50 ohms dummy load is used to Carsons rule is 40 kHz if the test a certain FM station. Suppose modulating frequency of the signal is the measured power is 12.5 W, what 5 kHz. Using the same signal, what is the voltage level of the second is the bandwidth if sidebands with sideband if a frequency of 5 kHz test more than 1% of the signal voltage tone is used and a 10 kHz frequency are considered? deviation? a. 61 kHz

a. 8.45Vrms b. 62 kHz

b. 8.56Vrms c. 60 kHz

c. 8.75Vrms d. 63kHz

d. 8.26Vrms 49. An FM transmitter operates with a 46. An FM receiver can sufficiently carrier power of 10 W. what is the receives only the carrier and the first total signal power if the modulation two sets of side bands. If the total index of the signal is 5? power of the signal is 20 W, a. 308W deviation of 25 kHz, and a b. 309W modulation index of 10, what is the c. 310W percentage of the total signal power d. 311W will it receive? 50. The maximum phase deviation given a. 96.62% to the signal by the noise voltage is b. 96.65% 0.01radian. What is the signal to c. 96.68% noise ratio at the detectors input? d. 96.56% a. 41dB 47. An FM receiver sufficiently receives b. 42dB c. 43dB signal that is modulated to 10 kHz d. 40dB deviation by a sine wave? 51. An FM receiver detects a 100 mV a. 5 kHz/V signal. A spurious signal is also b. 6 kHz/V detected by the receiver that resulted c. 7 kHz/V to an S/N of 40 dB at the detectors d. 8 kHz/V output. Determine the minimum S/N 55. An FM receiver uses a tuned ratio at the detectors output if the transformer operating at 10.7 MHz. modulating frequency is 2 kHz and what is the bandwidth using the frequency deviation of 50 kHz. optimum coupling factor if the a. 12dB primary circuit has a Q of 50 and the b. 13dB secondary has Q of 35? c. 14dB a. 383.6 kHz d. 15dB b. 383.7 kHz 52. An FM receiver is tuned at 99.1 c. 383.8 kHz MHz. what is the IF rejection ratio if d. 383.9 kHz the receiver consists of a single tuned 56. An FM super heterodyne receiver is circuit with Q of 45? tuned to a frequency of 88 MHz. a. 23dB what is the local oscillator frequency b. 24dB if low side injection is used at the c. 25dB mixer? d. 26dB a. 77.3 MHz 53. An FM detector receives an FM b. 77.4 MHz signal with a deviation of 15 kHz. c. 77.5 MHz What is the peak to peak output d. 77.6MHz voltage of the detector if its sensitivity is 75 microV/Hz? a. 2.25V b. 2.26V c. 2.27V d. 2.28V 54. An FM receiver uses PLL to detect the signal. What is the sensitivity of the VCO in the PLL if the output of MULTIPLE the detector is 1.25 Vp from an FM 1. A current change that is equal to twice its original value will correspond to a change of CHOICE a. 3 dB b. 9 dB c. 10 dB QUESTIONS d. 6 dB 2. What does a power difference of -3dB mean? a. A loss of one third of the power in b. A loss of one-half of the power c. A loss of 3 watts of power d. No significant change COMPREHENSIVE 3. A gain of 60 dB is the same as a gain of a. 10 volts/volt b. 100 volts/volt REVIEWER IN c. 1000 volts/volt d. 10,000 volts/volt COMMUNICATIO 4. ______is mathematically equal to the logarithm to the base ten of the power ratio P1 over P2. NS ENGINEERING a. bel b. dB Philander U. Lomboy, ECE c. bel/10 Benedetto D. Villanueva, ECE d. dB/2 5. Noise that is produced by the active components within the receiver. a. Thermal b. External c. Internal d. White Encoded by: 6. Noise due to random variation in the arrival TOL of charge carriers at the output electrode of ENT an active device a. Shot INO, b. Impulse Naza c. Thermal rio d. Dynamic 7. A network has a loss of 20 dB. What power M. II ratio corresponds to this loss VIL a. 0.01 LAF b. 0.1 c. 10 LOR d. 100 ES, 8. A receiver connected to an antenna whose Cind resistance is 60 ohms has an equivalent noise resistance of 40 ohms. Calculate the y A. receiver’s noise figure in decibels and its equivalent noise temperature. a. 1.67 & 194°K dB/NOISE b. 2.23 & 194°K Multiple choice. Encircle the letter which c. 1.67 & 174°K corresponds to your answer. d. 2.23 & 194°K 9. _____ Noise is the most prevalent noise 16. If a network connected in series have a gain found in urban areas and is normally caused of -0.5 dB, -0.3dB, -2dB and 6.8dB, the by the arc discharge from automobile or overall gain is aircraft ignition systems, induction motors, a. 2 dB switching gears, high voltage lines and the b. -2dB like. c. 4 dB a. Industrial d. -4dB b. Johnson 17. What is the gain, in dB, if the output to input c. Flicker ratio is 1000. d. Mixer a. 20 10. The noise figure of a totally noiseless device b. 30 is c. 40 a. Unity d. 10 b. Infinity 18. The following characteristics of noise exept c. Zero a. Unwanted energy d. 100 b. Predictable in character 11. Indicate the noise whose source is in a c. Present in the channel category different from that of the other d. Due to any cause three. 19. The equivalent noise temperature of the a. Solar amplifier is 25 °K what is the noise figure? b. Cosmic a. 10.86 c. Atmospheric b. 1.086 d. Galactic c. 0.1086 12. The ratio(in dB) of the power of a signal at d. 1.86 point to the power of the same signal at the 20. A receiver connected to an antenna whose reference point. resistance is 50 ohms has an equivalent a. Transmission Level Point noise resistance of 30 ohms. What is the b. Noise Figure receiver’s noise temperature? c. S/N Ratio a. 464°K d. Neper b. 754°K 13. A network has a power gain of -3dB. If the c. 400°K input power is 100 watts, the output power d. 174°K is 21. A theoretical antenna has a gain of 1dB. Its a. 50 watts gain in nepers is b. 55 watts a. 8.686 c. 60 watts b. 0.1151 d. 62 watts c. 6.868 14. Which of the following types of noise d. 0.5111 becomes of great importance at high frequencies? a. Shot 22. What is the equivalent output of a circuit in b. Random dBm, if it has an output of 10 watts? c. Impulse a. 10 dBm d. Transmit time b. 30dBm c. 20dBm 15. The input current of a network is 190 uA d. 40dBm and the output is 1.3 uA. The loss in 23. An amplifier with an input resistance of decibels is 1000 ohms is operating over a 4 MHz a. 20.2 bandwidth. Calculate the rms voltage if the b. 21.6 amplifier is operating at 27 °C. c. 28.6 a. 8.14 nV d. 43.3 b. 8.14 uV c. 6.6 nV d. dBV d. 6.6 uV 32. which of the following is not an actual 24. The value of a resistor creating thermal amount of power? noise is doubled. The noise power generated a. dB is therefore b. dBm a. Halved c. dBw b. Quadrupled d. dBk c. Doubled 33. In noise analysis, the reference temperature d. Unchanged is 25. One of the following is not a useful quantity a. 75 K for comparing the noise performance of b. 250 K receivers. c. 290 K a. Input noise voltage d. 300 K b. Equivalent noise resistance 34. Noise from distant panels, stars, galaxies c. Noise temperature and other celestial objects are called d. Noise figure a. Cosmic 26. Any unwanted form of energy that tends to b. Extraterrestrial interfere with the wanted signal is called c. Galactic a. Noise d. Black body b. Spectrum 35. Indicate which one of the following types of c. Radiation noise does not occur in transistors d. Absorption a. Shot noise 27. The correct symbol for decibel is b. Flicker noise a. DB c. Partition noise b. dB d. Resistance noise c. Db d. db 28. _____ is the noise created outside the receiver. a. Internal 36. Which of the following is not a source of b. External space noise c. Shot a. Sun d. Industrial b. Star c. Lightning d. Black body 29. _____ is the noise created by man. 37. Noise that is due to the random and rapid a. Solar motion of the charge carriers inside a b. Industrial resistive component. c. Extraterrestrial a. Johnson d. Galactic b. Thermal Agitation 30. A voltage change that is equal to twice its c. White original value correspond to a change of d. All of the above a. 3dB 38. Indicate the false statement. The square of b. 6dB the thermal noise voltage generated by a c. 9dB resistor is proportional to d. 10dB a. Its resistance 31. Indicate the voltage level in dB with b. Its temperature reference to one volt. This unit is used in c. Boltzmann’s Constant video or TV measurement d. The bandwidth over which it is a. dBW measured b. dBk 39. In a communication system, noise is likely c. dBm to affect the signal a. At the transmitter c. 1 dBm b. In the channel d. 7 dBm c. In the information source 48. The sum of three signals of 45dBm each is d. At the destination ______dBm. 40. The noise power generated by a resistor is a. 45 proportional to b. 135 a. Temperature c. 20 b. Bandwidth d. 50 c. a and b 49. It is characterized by high amplitude peaks d. NOTA of short duration in the total noise spectrum 41. Thermal noise is also known as a. Intermodulation voice a. Gaussian Noise b. Impulse noise b. White Noise c. Dropout c. Johnson noise d. Phase hits d. All of the above 42. This type of noise has a power spectrum which decreases with increasing frequency. It is most important at low frequencies from 50. Originally was determined by measuring the 0 to about 100 Hz). interfering effect of noise in a Type 144 a. Shot noise handset. A tone of 1 kHz, having a power b. Flicker noise level of 90dBm was selected as the c. Diode noise reference level. d. BJT noise a. Noise figure b. S/N ratio c. Signal Figure 43. Industrial noise extends up to what d. Figure of Merit frequency? 51. A power level of 50 uW could be expressed a. 500 MHz as: b. 500 GHz a. 1.39 dBm c. 500 THz b. -4.3 dBm d. 500 KHz c. 1 dBm 44. Impulse Noise is d. -13 dBm a. A function of current 52. If a power of 0.25mW is launched into a b. A shot duration pulse fiber system with an overall loss of 15 dB c. Dependent of frequency the output power would be: d. Dependent of temperature a. 250 u/W 45. When the power ratio of the output to input b. 31.6 uW of a circuit is 200. What is the gain in dB? c. 7.9 uW a. 23 d. 15 dBm b. 46 53. A system having an input power of 2 mW an c. -23 output power of 0.8mW has a loss of: d. -46 a. 2.98 dBm 46. What is the reference level for random noise b. 3.98 dB measurement, FIA weighted? c. 3.98 uW a. -82 dBm d. 1.98 mW b. -90 dBm 54. An output of -10 dB means that the power c. -85 dBm has been d. -77 dBm a. Halved in value 47. A 10 dB pad has an output level of -3 dBm. b. Increased by a factor of 10 The level at the input is: c. Reduced by a factor of 10 a. 13 dBm d. Doubled b. -7 dBm 55. Any unwanted form of energy interfering the reception of wanted signal is called such as lightning discharge. a. Noise a. Static noise b. Sideband b. Space noice c. Harmonics c. Atmospheric noise d. Modulation d. A or C 56. Is the reduction of signal amplitude as it passed over the transmission medium. a. Noise 64. Atmospheric or static noise becomes less b. Distortion severe at frequencies c. Attenuation a. Below 30 KHz d. Interference b. Between 30 KHz and 300 KHz c. Between 300 KHz and 30 MHz d. Above 30 MHz 57. Signal waveform perturbation or deviation 65. Considered as space noise or extraterrestrial caused by imperfect response of the system noise to the desired signal a. Solar noise a. Noise b. Cosmic noise b. Aliasing c. Black-body noise c. Distortion d. All of the above d. Interference 66. Which statement is true 58. Signal attenuation can be corrected by a. Industrial noise is usually of impulse a. Filtering type b. Modulation b. Distant stars produce atmospheric c. Equalization noise d. Amplification c. Active switches are sources of man- 59. Distortion in a waveform can be corrected made noise by d. Static noise is due to lightning a. Filtering discharges and other natural electric b. Modulation disturbances occurring in the c. Equalization atmosphere. d. Amplification 67. Noise performance of microwave system is 60. Signal contamination by extraneous or usually expressed in terms of external sources, such as, other transmitters, 4 KTBR a. Noise voltage, Vn= √ power lines, and machinery. a. Noise b. Noise power, Pn = KTB b. Distortion c. Noise temperature, Te = (F – 1)290 c. Harmonics d. Noise figure, F = (S/N)I / (S/N)o d. Interference 68. Which circuit contributes most to the noise 61. Man-made or industrial noise is also known at the receiver? as a. RF amplifier a. Noise b. Mixer b. Distortion c. Detector c. Interference d. Local Oscillator d. Thermal Noise 69. Which noise figure represents the lowest 62. The noise performance of a receiver or noise? circuit. It is expressed as ratio of the S/N a. 1.5 dB power at the output. b. 2.0 dB a. Noise figure c. 3.7 dB b. S/N ratio d. 4.1 dB c. Signal figure 70. Denote the interference of noise in dB above d. Figure of merit an adjusted reference noise. The adjusted 63. Noise that is caused by natural disturbances reference noise level was a 1 kHz tone, set at -85 dBm This unit of measurement is generally used a. dBa in Europe where the standard reference tone b. dBm is 800 hertz, 1 picowatt. c. dBa0 a. dBa d. pWp b. dBm c. dBaO d. pWp 71. The extent of noise referred to a test tone level of zero dBm. a. dBa 78. Noise produced mostly by lightning b. dBm discharges in thunderstorms. c. dBa0 a. White noise d. pWp b. Industrial noise 72. An amplifier operating over a 4 MHz c. Atmospheric noise bandwidth has a 100 Ω input resistance d. Extraterrestrial noise 79. Propagation of man made noise is chiefly by and is operating at 300°K. Determine the a. Transmission over power lines and noise power generated. by ground wave -14 a. 1.656 x 10 Watts b. Space wave b. 1656 nW c. Sky wave c. 1.656 pW d. None of these d. 1.656 uW 80. A more precise evaluation of the quality of a 73. Generally used when noise readings are receiver as far as noise is concerned measured using the C-message weighting a. S/N network. The reference level was 1 kHz b. VSWR tone, set at -90 dBm c. Noise factor a. dBa d. Noise margin b. dBm 81. NIF stands for c. dBaO a. Non-intrinsic figure d. dBmC b. Noise interference figure 74. The measurement of noise was made with a c. Noise improvement factor C-message filter, and the reading is taken at d. Narrow intermediate frequency a test point where the level is zero dBm. 82. External noise fields are measured in terms a. dBaO of b. dBmCo a. Dc values c. dBa b. Rms values d. dBmC c. Peak values 75. Which of the following is not an important d. Average values cause of distortion in DC signaling 83. Form of interference caused by rain, hail, a. line resistance snow or dust storms b. line inductance a. Shot noise c. line capacitance b. Galactic noise d. all of the above c. Impulse noise 76. There are a number of different sources of d. Precipitation static radio noise, the most important being 84. Extra-terrestrial noise is observable at a. Galactic noise frequencies from b. Man-made noise a. 0 to 20KHz c. Atmospheric noise b. 8 MHz to 1.43 GHz d. All f the above c. 5 to 8 GHz 77. The amount of noise power is measured d. 15 to 160 MHz using a psophometric weighting network. b. Distortion c. External noise 85. Industrial noise is observable from d. Internal noise a. 15 to 160 MHz 93. The frequency range wherein noise is said to b. 200 to 3000 MHz be intense. c. 0 to 10 kHz a. Noise equivalent bandwidth d. 8 Mhz to 1.43 GHz b. Spectral response 86. Noise that becomes significant at VHF range c. Cut-off frequency and above d. Noise cut-off frequency a. Atmospheric 94. Refers to the temperature that corresponds to b. Transit-time the spectral energy distribution of a noise.\ c. Galactic a. Absolute temperature d. White b. Temperature band 87. Noise figure for an amplifier with noise is c. Noise-equivalent temperature always d. Critical temperature a. 0 dB 95. A passive circuit, usually consisting of b. Infinite capacitance and/or inductance, that I c. Less than 1 inserted in series with the a-c power cord of d. Greater than 1 an electronic device which will allow the 88. The noise generated by the tube, transistor 60-Hz current to pass and suppressed high or integrated circuit in an amplifier. frequency noise components. a. White noise a. Noise filter b. Amplification noise b. Noise limiter c. Active noise c. Noise floor d. Dynamic Noise d. Noise quieting 89. Electrical noise inherent to a particular 96. What do you call the level of background device, circuit or system that remains when noise, relative to some reference signal. no other signal is present. a. Noise figure a. Shot noise b. Minimum noise b. Thermal noise c. Reference noise c. Background noise d. Noise floor d. Static noise 97. A circuit often used in radio receivers that 90. A wideband form of impulse noise generated prevents externally generated noise from by the electric arc in the spark plugs of an exceeding amplitude. They are also called internal combustion engine. This noise is a noise clippers common problem in mobile radio system. a. Noise floor a. Thermal noise b. Noise filter b. Shot noise c. Noise limiter c. Amplification noise d. Noise clamper d. Ignition noise 98. It is referred to as a short burst of 91. The amount of power in dB referred to one electromagnetic energy. Kilowatt a. Pulse a. dBW b. Noise pulse b. dBk c. Spike c. dBm d. Noise floor d. Dbv 99. The reduction of internal noise level in a frequency-modulated (FM) receiver as a result of an incoming signal. 92. Noise in any form of electromagnetic a. Noise quieting interference that can be traced to non-natural b. Noise limiting causes. c. Noise suppression a. Man-made noise d. Noise degredation 100.Noise generated within electronic c. Variable gain amplifier equipment by either passive or active d. Multiplexer components. 5. A modulator circuit performs what a. Shot noise mathematical operation on its two inputs? b. Thermal noise a. Addition c. Circuit noise b. Multiplication d. External noise c. Division d. Square root 6. The ratio of the peak modulating signal voltage to the peak carrier voltage is referred to as a. The voltage ratio b. Decibels c. The modulation index d. The mix factor 7. If m is greater than 1, what happens? a. Normal operation b. Carrier drops to zero c. Carrier frequency shifts d. Information signal is distorted

8. For ideal AM, which of the following is true? a. m = 0 b. m = 1 Modulation c. m < 1 Multiple choice. Encircle the letter which d. m > 1 corresponds to your answer. 9. The outline of the peaks of a carrier has the 1. Having an information signal change some shape of the modulating signal and is called characteristic of a carrier signal is called the a. Multiplexing a. Trace b. Modulation b. Waveshape c. Duplexing c. Envelope d. Linear mixing d. Carrier variation 2. Which of the following is not true about 10. Overmodulation occurs when AM? a. Vm > Vc a. The carrier amplitude varies. b. Vm < Vc b. The carrier frequency remains c. Vm = Vc constant. d. Vm = Vc = 0 c. The carrier frequency changes. 11. The values of Vmax and Vmin as read from an d. The information signal amplitude AM wave on oscilloscope are 2.8 and 0.3. changes the carrier amplitude. the percentage of modulation is 3. The opposite of modulation is a. 10.7 % a. Reverse modulation b. 41.4 % b. Downward modulation c. 80.6 % c. Unmodulation d. 93.3 % d. Demodulation 12. The new signals produced by modulation are 4. The circuit used to produce modulation is called called a. Spurious emissions a. Modulator b. Harmonics b. Demodulator c. Intermodulation products d. Sidebands above if the antenna resistance is 75 ohms? 13. A carrier of 880 kHz is modulated by a 3.5 a. 195 W kHz sine wave. The LSB and USB are, b. 631 W respectively, c. 507 W a. 873 and 887 kHz d. 792 W b. 876.5 and 883.5 kHz 21. In an AM signal, the transmitted information c. 883.5 and 876.5 kH is contained within the d. 887 and 873 kHz a. Carrier 14. A display of signal amplitude versus b. Modulating signal frequency is called the c. Sidebands a. Time domain d. Envelope b. Frequency Spectrum c. Amplitude Spectrum d. Frequency Domain 22. An AM signal without the carrier is called a(n) a. SSB 15. Most of the power in an AM signal is in the b. Vestigial sideband a. Carrier c. FM signal b. Upper sideband d. DSB c. Lower sideband 23. What is the minimum AM signal needed to d. Modulating signal transmit information? 16. An AM signal has a carrier power of 5 W. a. Carrier plus sidebands the percentage of modulation is 80% the b. Carrier only total sideband power is c. One sideband a. 0.8 W d. Both sideband b. 1.6 W 24. The main advantage of SSB over standard c. 2.5 W AM or DSB is d. 4.0 W a. Less spectrum space is used 17. For 100 % modulation, what percentage of b. Simpler equipment is used power is in each sideband? c. Less power is consumed a. 25 % d. A higher modulation percentage b. 33.3 % 25. In SSB, which sideband is the best to use? c. 50 % a. Upper d. 100 % b. Lower 18. An AM transmitter has a percentage of c. Neither modulation of 88. The carrier power is 440 d. Depends upon the use W. The power is 440W. The power in one 26. The typical audio modulating frequency sideband is range used in radio and telephone a. 85 W communication is b. 110 W a. 50 Hz to 5 kHz c. 170 W b. 50 Hz to 15 kHz d. 610 W c. 100Hz to 10kHz 19. An AM transmitter antenna current is d. 300 Hz to 3 kHz measured with no modulation and found to 27. An AM signal with a maximum modulating be 2.6 amperes. With modulation, the signal frequency of 4.5 kHz has a total current rises to 2.9 amperes. The percentage bandwidth of of modulation is a. 4.5 kHz a. 35 % b. 6.75 kHz b. 70 % c. 9 kHz c. 42 % d. 18 kHz d. 89 % 28. The modulation system used for telegraphy 20. What is the carrier power in the problem is a. Frequency-shift keying b. Independent sideband emission b. Two-tone modulation c. Lincomlex c. Pulse-code modulation d. Vestigal sideband transmission d. Single-tone modulation 36. Amplitude modulation is the same as a. Linear mixing b. Analog multiplication c. Signal summation 29. The process of translating a signal, with or d. Inductor without modulation, to a higher or lower 37. In a diode modulator, the negative half of frequency for processing is called the AM wave is supplied by a(n) a. Frequency multiplication a. Tuned circuit b. Frequency division b. Transformer c. Frequency shift c. Capacitor d. Frequency conversion d. Inductor 30. Frequency translation is carried out by a 38. Amplitude modulation can be produced by circuit called a a. Having the carrier vary a a. Translator resistance b. Convertor b. Having the modulating signal vary a c. Balanced modulator capacitance d. Local oscillator c. Varying the carrier frequency 31. An input signal of 1.8 MHz is mixed with a d. Varying the gain of an amplifier local oscillator of 5 MHz. A filter selects the 39. Amplitude modulators that vary the carrier difference signal. The output is amplitude with the modulating signal by a. 1.8 MHz passing it through an attenuator work on the b. 3.2 MHz principle of c. 5 MHz a. Rectification d. 6.8 MHz b. Resonance 32. One type of pulse communications system c. Variable resistance uses pulse that appear as a group, and which d. Absorption vary in number according to the loudness of 40. The component used to produce AM at very the voice. This type of pulse modulation is high frequencies is a called a. Varactor a. Pulse duration modulation b. Thermistor b. Pulse amplitude modulation c. Cavity resonator c. Pulse code modulation d. PIN diode d. Pulse position modulation 41. Amplitude modulation generated at a very 33. An SSB transmitter produces a 400-V peak low voltage or power amplitude is known as to peak signal across a 52-Ω antenna load. a. High-level modulation The PEP output is b. Low-level modulation a. 192.2 W c. Collector modulation b. 384.5 W d. Minimum modulation c. 769.2 W 42. A collector modulator has a supply voltage d. 3077 W of 48 V. The peak-to-peak amplitude of the 34. The output power of an SSB transmitter is modulating signal for 100 percent usually expressed in terms of modulation is a. Average power a. 24 V b. RMS power b. 48 V c. Peak-to-peak power c. 96 V d. Peak envelope power d. 120 V 35. The letter-number designation B8E is a form of modulation also known as a. Pilot-carrier system 43. A collector modulated transmitter has a d. DSB supply voltage of 24 V and collector current 51. The principal circuit in the popular of 0.5 A. The modulator power for 100 1496/1596 IC balanced modulator is a percent modulation is a. Differential amplifier a. 6 W b. Rectifier b. 12 W c. Bridge c. 18 W d. Constant current source d. 24 W 52. The most commonly used filter in SSB 44. The circuit that recovers the original generators uses modulating information from an AM signal a. LC network is known as a b. Mechanical resonators a. Modulator c. Crystals b. Demodulator d. RC networks and op amps c. Mixer 53. The equivalent circuit of a quartz crystal is a d. Crystal set a. Series resonant circuit 45. The most commonly used amplitude b. Parallel resonant circuit demodulator is the c. Neither a nor b a. Diode mixer d. Both a and b b. Balanced modulator 54. A crystal lattice filter has crystal frequencies c. Envelope detector of 27.5 and 27.502 MHz. The bandwidth is d. Crystal filter approximately 46. A circuit that generates the upper and lower a. 2 kHz sidebands but no carrier is called a(n) b. 3kHz a. Amplitude modulator c. 27.501 MHz b. Diode detector d. 55.502 MHz c. Class C amplifier 55. An SSB generator has a sideband filter d. Balanced modulator centered at 3.0 MHz. The modulating signal 47. The inputs to a balance modulator are 1 is 3kHz. To produce both upper and lower MHz and a carrier of 1.5 MHz. The outputs sidebands, the following carrier frequencies are must be produced: a. 500 kHz a. 2.7 and 3.3 MHz b. 2.5 MHz b. 3.3 and 3.6 MHz c. 1.5 MHz c. 2997 and 3003 kHz d. Both a and b d. 3000 and 3003 kHz 48. A widely used balanced modulator is called 56. In the phasing method of SSB generation, the one sideband is canceled due to a. Diode bridge circuit a. Phase shift b. Full-wave bridge rectifier b. Sharp selectivity c. Lattice Modulator c. Carrier suppression d. Balanced bridge modulator d. Phase inversion 49. In a diode ring modulator, the diodes act like a. Variable resistors b. Switches 57. A balanced modulator used to demodulate a c. Rectifiers SSB signal is called a(n) d. Variable capacitors a. Transporter b. Product detector c. Converter d. Modulator 50. The output of a balanced modulator is 58. Frequency translation is done with a circuit a. AM called a b. FM a. Summer c. SSB b. Multiplier c. Filter changing? d. Mixer a. Shape 59. The inputs to a mixer are fo and fm. In down b. Phase conversion, which of the following mixer c. Frequency output signals is selected? d. Amplitude a. Fo 67. Maximum frequency deviation of a PM b. Fm signal occurs at c. Fo – fm a. Zero crossing points d. Fo + fm b. Peak positive amplitude 60. Mixing for frequency conversion is the same c. Peak negative amplitude as d. Peak positive or negative amplitudes a. Rectification 68. A 100-MHz carrier is deviated 50 KHz by a b. AM 4 kHz signal. The modulation index is c. Linear summing a. 5 d. Filtering b. 8 61. Which of the following can be used as a c. 12.5 mixer? d. 40 a. Balanced modulator 69. The maximum deviation of an FM carrier is b. FET 2 kHz by a maximum modulating signal of c. Diode modulator 400 Hz. The deviation ratio is d. All the above a. 0.2 62. The desired output from a mixer is usually b. 5 selected with a c. 8 a. Phase-shift circuit d. 40 b. Crystal filter 70. According the Nyquist theorem, the c. Resonant circuit sampling rate that can be used in a PCM d. Transformer system is _____ the highest audio frequency 63. The amount of frequency deviation from the a. Once carrier center frequency in an FM b. Eight times transmitter is proportional to what c. Twice characteristic of the modulating signal? d. Thrice a. Amplitude b. Phase c. Angle 71. SSB transmission requires only ______of d. Duty Cycle the bandwidth for a DSBFC a. ¼ b. 2/3 c. ½ 64. Both FM and PM are types of what kind of d. ¾ modulation? 72. Which of the following pulse modulation a. Amplitude systems is analog? b. Phase a. Delta c. Angle b. Differential PCM d. Duty Cycle c. PWM 65. If the amplitude of the modulating signal d. PCM decreases, the carrier deviation 73. Which of the following is not a major a. Increases benefit of FM over AM? b. Decreases a. Greater efficiency c. Remains constant b. Noise immunity d. Both b and c c. Capture Effect 66. In PM, a frequency shift occurs while what d. Lower Complexity and Cost characteristic of the modulating signal is 74. The primary disadvantage of FM is it a. Higher cost and complexity d. Increased by 50 percent b. Excessive use of spectrum space 82. One of the advantages of base modulation c. Noise susceptibility over collector modulation of a transistor d. Lower efficiency class C amplifier is 75. The phenomenon of a strong FM signal a. The lower modulating power dominating weaker signal on a common required frequency is referred to as the b. Higher power output per transistor a. Capture effect c. Better efficiency b. Blot out d. Better linearity c. Quieting factor 83. A carrier simultaneously modulated by two d. Dominating syndrome sine waves with modulation indices of 0.3 76. If the plate supply voltage for a plate- and 0.4; the total modulation index modulated class C amplifier is E, the a. 1 maximum plate-cathode voltage could be b. Cannot be calculated unless the almost as high as phase relations are known a. 4E c. 0.5 b. 3E d. 0.7 c. 2E 84. In the stabilized reactance modulator AFC d. E system, 77. In a low-level AM system, amplifiers a. The discriminator must have a fast following the modulated stage must be time constant to prevent a. Linear devices demodulation b. Harmonic devices b. The higher the discriminator c. Class C amplifiers frequency, the better the oscillator d. Nonlinear devices frequency stability c. The discriminator frequency must not be too low, or the system will 78. If the carrier of a 100 percent modulated AM fail wave is suppressed, the percentage power d. Phase modulation is converted into saving will be FM by the equalizer circuit a. 50 b. 150 c. 100 85. In the spectrum of a frequency of a d. 66.66 frequency-modulated wave 79. Leak-type bias is used in a plate-modulated a. The carrier frequency disappears class C amplifier to when the modulation index is large a. Prevent tuned circuit damping b. The amplitude of any sideband b. Prevent excessive grid current depends on the modulation index c. Prevent overmodulation c. The total number of sidebands d. Increase the bandwidth depends on the modulation index 80. The output stage of a television transmitter d. The carrier frequency cannot is most likely to be a disappear a. Plate-modulated class C amplifier 86. The difference between phase and frequency b. Grid-modulated class C amplifier modulation c. Screen-modulated class C amplifier a. Is purely theoretical because they are d. Grid-modulated class A amplifier the same in practice 81. The modulation index of an AM wave is b. Is too great to make the two systems changed from 0 to 1. The transmitted power compatible is c. Lies in the poorer audio response of a. Unchanged phase modulation b. Halved d. Lies in the different definitions of c. Doubled the modulation index 87. Indicate the false statement regarding the a. Better noise immunity is provided Armstrong modulation system. b. Lower bandwidth is required a. The system is basically phase, not c. The transmitted power is more useful frequency, modulation d. Less modulating power is required b. AFC is not needed, as a crystal 94. One of the following is an indirect way of oscillator is used generating FM. This is the c. Frequency multiplication must be a. Reactance FET modulator used b. Varactor diode modulator d. Equalization is unnecessary c. Armstrong modulator 88. An FM signal with a modulation index mf is d. Reactance bipolar transistor passed through a frequency tripler. The modulator wave in the output of the tripler will have a 95. Indicate the false statement regarding the modulation index of advantages of SSB over double-sideband, a. mf/3 full-carrier AM. b. mf a. More channel space is available c. 3 mf b. Transmitter circuits must be more d. 9mf stable, giving better reception 89. An FM signal with a deviation δ is passed c. The signal is more noise resistance through a mixer, and has its frequency d. Much less power is required for the reduced fivefold. The deviation in the output same signal strength of the mixer is 96. When the modulation index of an AM wave a. 5 δ is doubled, the antenna current is also b. Indeterminate doubled. The AM system being used is c. δ/5 a. A3H d. δ b. A5C 90. A pre-emphasis circuit provides extra noise c. A3J immunity by d. A3 a. Boosting the bass frequencies 97. Indicate which of the following advantages b. Amplifying the higher audio of the phase cancellation method of frequencies obtaining SSB over the filter method is false c. Pre-amplifying the whole audio band a. Switching from one sideband to the d. Converting the phase modulation to other is simpler FM b. It is possible to generate SSB at any 91. Since noise phase modulates the FM wave, requency as the noise sideband frequency approaches c. SSB with lower audio frequencies the carrier frequency, the noise amplitude present can be generated a. Remains constant d. There are more balanced b. Decreased modulators; therefore the carrier c. Increased is suppressed better d. Equalized 98. The most commonly used filter in SSB generation are a. Mechanical 92. When the modulating frequency is doubled, b. RC the modulation index is halved, and the c. LC modulating voltage remains constant. The d. Low- pass modulating system is 99. Indicate in which one of the following only a. Amplitude modulation one sideband is transmitter b. Phase modulation a. A3H c. Frequency modulation b. A3 d. Any of the three c. A3B 93. Indicate which one of the following is not an d. A5C advantage of FM over AM 100.A3A modulation is sometimes used to a. Allow the receiver to have a b. Waveguide frequency synthesizer c. Fiber optic cable b. Simplify the frequency stability d. All of these problem in reception 4. To couple a coaxial line to a parallel wire c. Reduce the power that must be line, it is best to use a _____ transmitted a. d. Reduce the bandwidth required for b. Directional coupler transmission. c. Balun d. All of these 5. Impedance inversion may be obtained with a. An open circuited stub b. A short circuited stub c. A quarterwave line d. A half-wave line 6. To be properly matched, the ratio of maximum to minimum voltage along a transmission line should be equal to a. 50 b. 10 c. 2 d. 1

7. When ZL ≠ Zo, the powersent down the line toward the load is called the a. The incident power Transmission Lines b. The reflected power Multiple choice. Encircle the letter which c. The power dissipation corresponds to your answer. d. The carrier power 1. In practice, the transmission lines are almost 8. For transmission line load matching over a connected to antennas that have a _____. range of frequencies, it is best to use a a. Resistive load whose resistance is a. Balun greater than the characteristic b. Broadband directional coupler impedance of the line c. Double stub b. Resistive load whose resistance is d. Single adjustable stub less than the characteristic 9. A short section of a transmission line, open impedance of the line or shorted that is used to match the c. Resistive load at the resonant impedance of the line to that of an antenna frequency or transmitter. d. Capacitive load a. Slotted line 2. When the transmission line is matched to the b. Stub load, it c. Wavetrap a. Transfers maximum current to the d. Lecher wire load 10. The property of a material that determines b. Transfers maximum voltage to the how much electrostatic energy can be stored load per unit volume when voltage is applied c. Transfers maximum power to the a. Permeability load b. Magnetic effect d. Reduces the load current c. Capacitance 3. Conventional transmission media include d. Permittivity a. Twisted cable pair 11. The value of the total opposition of the transmission media to the flow of 18. The characteristic impedance of a electromagnetic field energy is called transmission line is determined by a. Characteristic impedance a. Its length b. Velocity factor b. Its height above ground c. Standing waves c. Its physical construction d. Reflected waves d. The operating frequency 12. When mismatch is great, this power actually 19. When the diameter of two conductors of a cause damage to the transmitter or the line two-wire transmission line is held constant, itself. the effect of decreasing the distance between a. The incident power the conductors is to b. The reflected power a. Decrease the impedance c. The power dissipation b. Increase the surge impedance d. The carrier power c. Increase the radiation resistance 13. What is the velocity factor for non-foam d. Decrease SWR dielectric 50 or 75 ohm flexile coaxial cable such as RG 8, 11, 58 and 59? a. 270 b. 0.10 20. Considering a coaxial transmission line, c. 0.66 maximum voltage on the line divided by the d. 0.30 minimum voltage equals the 14. The measure of the superiority of a material a. Characteristic impedance over a vacuum as a path for magnetic lines b. ISWR of force is c. VSWR a. Permittivity d. Inductive reactance b. Permeability 21. In a transmission line, if the SWR or c. Conductivity maximum current to a minimum current d. Resistivity ratio of 2:1, the ratio of the maximum 15. The number of standing waves on the wire is voltage to the minimum voltage is equal to the length of the wire divided by a a. 1:4 half wavelength. The principle which allows b. 4:1 antennas to operate at different frequencies c. 1:2 which are integral multiples of the d. 2:1 fundamental frequency is called______. 22. Transmission lines are either balanced or a. Harmonic operation unbalanced with respect to b. Decimonic operation a. Negative terminal c. Electromagnetic reverberation b. Input d. Asynchronous operation c. Ground 16. A coax line has an attenuation of 2.4 dB per d. Positive terminal 100 ft. the attenuation for 2.75 ft. is _____ 23. The load is properly matched with the dB. transmission line if the standing wave ratio a. 2.4 is equal to b. 4.8 a. 50 c. 3.3 b. 10 d. 6.6 c. 5 17. When a quarter wave stub is used to match a d. 1 600 ohm antenna to aline of 52 ohms, the 24. The radiation resistance of a quarterwave impedance of the matching stub must be antenna is ____ ohms. a. 49 ohms a. 176 b. 288 ohms b. 200 c. 72 ohms c. 150 d. 144 ohms d. 300 25. A radio transmission line of 500 ohms impedance is to be connected to an antenna characteristic impedance of the line, there having an imepedance of 200 ohms. What is are _____ standing waves. the impedance of a quarter wave matching a. More line? b. Less a. 300 c. No b. 316 d. Ten(10) c. 316.5 33. VSWR stands for d. 361 a. Voltage sending wave ratio 26. The VSWR for a line terminated in its Zo is b. Voltage receiving wave ratio a. 0 c. Very small wave radiation b. 1 d. Voltage standing wave ratio c. 1.5 d. Infinity 34. Reflections on a transmission line can occur 27. Which of the following is used to measure when SWR? a. Impedance of the source and load are a. Multimeter matched b. Reflectometer b. Impedance of the source and the c. Spectrum analyzer load are mismatched d. Oscilloscope c. Resonance conditions are obtained 28. A 75 – j50 ohm load is connected to a d. Power transfer between source and coaxial transmission line of Zo = 75 ohms at load is maximum 10 GHz. The best method of matching 35. A transmission line with characteristic consists in connecting impedance (Zo) of 300 ohms is terminated a. A short circuited stub at the load in a resistance load (RI). If by measurement, b. A capacitance at some specific the minimum and maximum voltage through distance from the load the load are 12 and 20 micro volts, c. An inductance at the load respectively, what is the SWR? d. A short-circuited stub at some a. 1.67 specific distance from the load b. 0.6 29. For a two-wire line, Zo is higher when c. 6.7 a. The wire size is small with respect d. 3.67 to the spacing of the conductors 36. A measure of the mismatched between line b. The spacing is varied in accordance and load impedance is called as with the frequency a. Reflection coefficient c. The D:d ratio is smaller b. Standing wave ratio d. The wire is large with respect to the c. Loss spacing of the conductors d. Standing waves 30. A resultant wave due to the combination of 37. Transmission lines when connected to incident and reflected wave antenna have a. Electromagnetic wave a. Capacitive load b. Sine wave b. Resistive load whose resistance is c. Standing wave less than characteristic impedance d. Current c. Resistive load at the resonant 31. For transmission line load matching over a frequency range of frequencies, it is best to use a d. Resistive load whose resistance is a. Balun greater than the characteristic b. Broadband directional coupler impedance of the line c. Double stub 38. At matched condition, SWR is equal to d. Single stub a. Zero 32. If the load impedance matches the b. One c. 100 having an input impedance of 150 ohms. d. Infinite The impedance if a quarter wave matching 39. An HF transmission line has a characteristic line is ___ ohms impedance of 600 ohms and is terminated by a. 212 an antenna. The SWR along the line when b. 450 the antenna impedance is 500 ohms is c. 600 a. 1.2:1 d. 150 b. 1:2.1 46. The ratio of the reflected voltage to the c. 2:1 incident voltage on the transmission line is d. 1:2 termed as 40. A characteristic of an infinite transmission a. Reflection coefficient line is that b. Standing wave ratio a. The impedance in equals c. Loss impedance out d. Standing waves b. It carries waves at the velocity of 47. Indicate the three types of transmission line light energy losses c. It can be connected to mismatched a. Radiation, I(squared) R and loads dielectric Heating d. The impedance varies with the b. Conductor heating, dielectric heating length of the line and radiation resistance c. I(squared)R, RL and temperature d. Dielectric separation insulation 41. A quarter wave transmission line shorted at breakdown and radiation the end: a. Has the characteristics of parallel tuned circuit 48. Termination means b. Has the characteristics of a series a. Load connected to the output end tuned circuit of a transmission line c. Has a minimum current at the end b. Result of disconnecting a line from a d. Reflects a low impedance to the transmitter supply c. Looking back impedance of a line 42. The outer conductor of a coaxial with no load transmission line is usually grounded at the: d. Result of cutting both ends of a a. Input and output conductor b. Output only 49. When transmission line uses ground return, c. Input only it is called a/n _____ line. d. Point of infinite resistance a. Ungrounded 43. A certain feedline has a high SWR. It can be b. Unbalanced caused by: c. Grounded a. An impedance mismatched d. Balanced b. Use of non-resonant line 50. Permeability is the measure of superiority of c. Matching the load to the line a material over a vacuum as a path of d. Excessive transmitter output magnetic lines of force. The permeability of 44. If the input impedance of an antenna is 300 free space is equal to _____ henry/meter ohms and it is fed with a 600 ohm balanced a. 1.257 x 10-6 transmission line, the SWR on the line is b. 1.527 x 10-6 a. 4 c. 7.251 x 10-6 b. 3 d. 5.217x10-6 c. 2 51. The most commonly used transmission line d. 0.5 is a 45. A radio transmission line of 300 ohms a. Two-wire balanced line impedance to be connected to an antenna b. Single line c. Three-wire line transformer used, directly connected to the d. Coax load has a Zo of ____ ohms. 52. The characteristic impedance of a a. 245 transmission line does not depend upon its b. 425 a. Length c. 524 b. Conductor diameter d. 254 c. Conductor spacing 59. What quarter wave transformer will match a d. Thickness of armor 100 ohm-lne to an antenna whose value is 53. What is the impedance of a balance 4-wire 175 ohms? with a diameter of 0.25cm and spaced 2.5 a. 150 ohms cm apart using an insulator with a dielectric b. 137.5 ohms constant of 2.56? c. 132.29 ohms a. 100 ohms d. 16.58 ohms b. 65 ohms 60. The mismatch between antenna and c. 75 ohms transmission line impedance cannot be d. 50 ohms corrected by 54. It is required to match a 73-ohm antenna to a a. Using an LC network 600 ohm polyethylene coaxial feeder line, b. Adjusting antenna length with a velocity factor of 0.66 by means of a c. Using a balun quarter wave matching a transformer. At a d. Adjusting the length of the frequency of 150MHz, the impedance of the transmission line matching section is____ ohms. a. 209.28 b. 310.5 c. 150.28 61. A pattern of voltage and current variation d. 450.82 along a transmission line not terminated in 55. If the terminating impedance is exactly ints characteristic impedance is called equal to the characteristic impedance of the a. An electric field transmission line, the return loss is____ b. Radio waves a. Zero c. Standing waves b. Infinity d. Magnetic field c. One 62. The most desirable value of SWR on a d. Negative transmission line is 56. The characteristic impedance of a a. 0 transmission line is the impedance measured b. 1 at the ____ when its length is infinite. c. 2 a. Shorted end of the line d. Infinity b. Midsection 63. In transmission lines, the most desisrable c. Input reflection coefficient is d. Output a. Zero 57. The characteristic impedance of a b. 0.5 transmission line is 70 ohms and has a load c. 1 of 35 ohms. The SWR and reflection d. Infinity coefficient are _____ and _____ 64. At very high frequencies, transmission lines respectively are used as _____. a. 2 and 0.333 a. Tuned circuits b. 1 and 0.666 b. Antennas c. 2 and 0.666 c. Insulators d. 1 and 0.333 d. Resistors 58. It is required to match a 200 ohm load to a 65. What is the reflection coefficient of a 100 300 ohm transmission line to reduce the ohm characteristic impedance line and a 300 SWR and attain resonace. A quarter wave ohm load? a. 0.25 at the center between grounded parallel b. 0.3 planes separated by 1mm apart. The wire is c. 0.5 held by a material with a velocity factor of d. 0.75 0.75 66. The minimum voltage along a transmission a. 85 ohms line is 260 volts, while the maximum is 390 b. 63 ohms volts. The SWR is c. 50 ohms a. 0.67 d. 75 ohms b. 1.0 73. Coaxial lines are used on those system c. 1.2 operating ______. d. 1.5 a. Below 2 GHz 67. A single conductor running from the b. At 300 MHz transmitter to the antenna c. Above 10 KHz a. RG-8/U d. Above 10 GHz b. Single line wire 74. Referred to the dielectric constant of a c. Twin-lead transmission line material d. Microstrip a. Inductance and capacitance b. Velocity factor c. Characteristic impedance 68. What characteristic impedance is needed to d. Propagation velocity match a 50-ohm line to a 300 ohm-load? a. 221 ohms b. 122 ohms 75. The main advantage of the two-hole c. 212 ohms directional coupler is d. 112 ohms a. Low directional coupling 69. Indicate the false statement. The SWR on a b. Poor directivity transmission line is infinity; the line is c. High SWR terminated in d. Narrow bandwidth a. Short circuit 76. To couple a coaxial line to a parallel-wire b. A complex impedance line, it is best to use a c. An open circuit a. Slotted line d. A pure reactance b. Balun 70. A (75 – j50) Ω load is connected to a coaxial c. Directional coupler transmission line of Zo = 75 Ω at 10 GHz. d. Quarter-wave transformer The best method of matching consists in 77. What is the meaning of the term velocity connecting factor of a transmission line? a. A short circuited stub a. The index of shielding for coaxial b. An inductance at the load cable c. A capacitance at some specific b. The velocity of the wave on the distance from the load transmission line multiplied by the d. A short circuited stub at some velocity of light in a vacuum specific distance from the load c. The ratio of the characteristic 71. The velocity factor of a transmission line impedance of the line to the a. Depends on the dielectric constant terminating impedance of the material used d. The velocity of the wave on the b. Increases the velocity along the transmission line divided by the transmission line velocity of light in a vacuum c. Is governed by the skin effect 78. A transmission line consisting of two d. Is higher for a solid dielectric than conductors that have equal resistance per for air unit length. 72. What is the characteristic impedance of a a. Unbalance line single wire with diameter d=0.25mm placed b. Open-wire line c. Balanced line b. Parallel resonant circuit d. Coaxial line c. Capacitor 79. Which if the following is not a common d. Inductor transmission line impedance? 87. A shorted half-wave line at the operating a. 50 Ω frequency acts like a(n) b. 75 Ω a. Capacitor c. 120 Ω b. Inductor d. 300 Ω c. Series resonant circuit 80. For a maximum absorption of power at the d. Parallel resonant circuit antenna, the relationship between the 88. At UHF and microwave frequencies, characteristic impedance of the line Zo and transmission lines are commonly used as the load impedance Zl should be a. Antenna a. Zo = ZL b. Coupler b. Zo > ZL c. Resonant circuit c. Zo < ZL d. Transformer d. Zo = 0 81. Which of the following determines the characteristics of a transmission line? a. Inductance b. Capacitance 89. The transmission medium subjects the c. Physical dimensions transmitted signal to be d. Length a. Modulated b. Amplified c. Attenuated 82. In the study of transmission cable, twin lead d. Boosted is also referred to as a ______. 90. Transmission line is a two-wire cable that a. Twisted pair connects the transmitter to the antenna or the b. Double cable antenna to the receiver. The purpose of the c. Ribbon cable transmission line is to d. Open pair a. Amplify the RF signal 83. A 50 Ω coax is connected to a 73 Ω the b. Modulate the signal SWR is c. Carry the RF energy for the a. 0.685 desired distance b. 1 d. All of the above c. 1.46 91. These conductors are uniformly spaced by d. 2.92 insulators. They have low losses at low 84. A ratio expressing the percentage of incident medium frequencies and are economical to voltage reflected on a transmission line is construct and maintained known as the a. Coaxial cables a. Velocity factor b. Open-wire transmission lines b. Standing-wave ratio c. Optical cables c. Reflection coefficient d. Waveguides d. Line efficient 92. To prevent radiation losses and interference 85. Three feet is one wavelength at a frequency from external sources, the inner conductor of of this transmission line is completely a. 100 MHz enclosed with a metal sheath or braid b. 164 MHz a. Coaxial cable c. 300 MHz b. Open-wire transmission lines d. 328 MHz c. Optical cables 86. An open quarter-wave line at the operating d. Waveguides frequency acts like a(n) 93. The term “balanced line” means that a. Series resonant circuit a. Both conductors carry currents that flow in opposite directions impedance is b. Conductors present equal a. Kept constant capacitance to ground b. Decreased c. One conductor is connected to c. Increased ground d. Halved d. Both A and B 94. The characteristic impedance of a transmission line is determined by: a. Its operating frequency b. Its length c. Its physical size and arrangement d. The signal applied at the input terminal 95. The disturbance parameters of the transmission line are: the series resistance; Wave Propagation the series inductance; the shunt capacitance Multiple choice. Encircle the letter which and the shunt conductance. What parameter corresponds to your answer. was determined due to dielectric losses? 1. Whether or not polarization of an antenna is a. Series resistance linear depends on changes in direction in b. Series inductance which: c. Shunt capacitance a. The direction in which the electric d. Shunt conductance plane is radiated. 96. Shunt capacitance was determined due to: b. The horizontal or vertical plane of a. Conductors were closed to each the electric wave. other c. The direction in which magnetic b. The length and diameter of the wave is radiated. conductors d. None of these c. Dielectric loses 2. The D, E and F layers of the ionosphere are d. Flux linkages called 97. Series resistances was determined due to: a. Mark-Space Layers a. Conductors were closed to each b. Davidson-Miller Layers other c. Kenelly Heaviside Layers b. The length and diameter of the d. Maxwell Layer conductors 3. ______refers to the ratio of an electric c. Dielectric losses field component to a magnetic field d. Flux linkages component at the same point of the wave. 98. At radio frequencies was determined due to: a. Characteristics impedance a. Characteristic b. Load impedance b. Inductive reactance is much larger c. Intrinsic impedance than the shunt conductance d. Wave impedance c. Capacitive reactance is much larger 4. The field strength of a radio signal varies than the shunt conductance according to the output or transmitted power d. Both b and c and the distance of the receiver from the 99. Determine the characteristic impedance of a transmitter. This wave behavior is described transmission line which has a capacitance of by 30 pF/m and an inductance of 75 nH/m a. The field strength a. 5 Ω b. Huygen’s Principle b. 50 Ω c. Faraday’s Law c. 500 Ω d. Inverse Square Law d. 5 K Ω 5. The antenna theory states that reception and 100.If a charge in the dielectric material transmission functions are interchangeable is decreases the capacitance, the characteristic a. Poynting Theorem b. Snell’s Law b. Vertically c. Huygen’s Principle c. Positively d. Law of Reciprocity d. Horizontally 6. The frequency band where electromagnetic 13. The property of a material that determines waves travel in straight path or in a direct how much change electrostatic energy can line of sight between the transmitter and be stored per unit volume when voltage is receiver antenna is applied a. ELF a. Miller effect b. HF b. Permeability c. VLF c. Capacitance d. VHF and above d. Permitivity 14. According to this law or principle, a wavefront may be considered to consist of 7. This mode of electromagnetic wave an infinite number of isotropic radiators, propagation uses the earth’s surface or each one sending out wavelets, always away curvature as a guide to transmit vertically from the source. polarized waves a. Snell’s Law a. Sky wave b. Maxwell’s Law b. Tropospheric wave c. Huygen’s Principle c. Transionospheric wave d. Archimedes Principle d. Ground wave 15. A number, which when multiplied by the 8. Frequencies in the UHF range propagate by speed of light in free space gives the speed means of of light in the medium in question is a. Ground waves a. Fibonacci number b. surface waves b. Fermat’s number c. sky waves c. Velocity factor d. space waves d. K-factor 9. the ground wave eventually disappear as it 16. The ability of a radio wave to be bent moves farther away from the transmitter, slightly over the edge of a sharp obstacle because of such as a steep hill or mountain top is a. tilting a. Diffraction b. reflection b. Reflection c. refraction c. Refraction d. diffraction d. Attenuation 10. as electromagnetic waves travel in free 17. A space wave is space, only one of the following can happen a. Sky wave a. absorption b. Radio wave b. attenuation c. Surface wave c. refraction d. Line of sight propagation wave d. reflection 18. It is a diagram indicating the intensity in 11. In polarization diversity, two signals are volts/meter, in all directions, of the radiated a. Both polarized at one specific filed of an antenna as it would occur under loacation actual operating conditions. b. Vertically and horizontally a. Constellation diagram polarized separately b. Argand diagram c. Polarized in the same manner c. Funicular diagram d. Vertically and horizontally polarized d. Radiation pattern using a common antenna 19. Equivalent to capacitance in electrical 12. If the direction of the electric field of a radio circuits wave is horizontal. That wave is known to a. Inductance be _____ polarized. b. Permittivity a. Negatively c. Permeability d. Power density than reflected waves 20. All of these cause attenuation except d. Both and b a. Tilting 26. The process by which a radio wave is bent b. Ground absorption and returned to earth from one medium to c. Atmospheric absorption another after striking them is d. Surface wave propagation a. Reflection 21. The transmission of radio waves far beyond b. Refraction line of sight distances by using high power c. Diffraction and large transmitting antennas to beam the d. Absorption signal upward into the atmosphere and a 27. An incident, traveling obliquely from one similar large receiving antenna to pick up a medium to another, will undergo a change in small portion of the signal scattered by the direction if the velocity of the wave in one atmosphere is called medium is different from that in the other a. Forward scatter propagation and the ratio of the sine of the angle of b. Beyond the horizon propagation incidence to the sine of the angle of c. Either a or b refraction is the same ratio of respectively d. Meteoric Scatter Propagation wave velocities in these media. This law is 22. The apparent height of an ionized layer of called the atmosphere; as determined from the time a. Snell’s Law interval between the transmitted signal and b. Fisher’s Law the ionospheric echo at vertical incidence. c. Hooke’s Law This height is the maximum height reached d. Newton’s Law if the actual paths are projected forming 28. The lowest layer of the ionosphere which straight lines from the ascent to the descent exists between 50 to 90 km from the earth’s of waves. surface and reflects VLF and LF waves a. Optimum height while absorbing MF and HF waves during b. Virtual height daytime is the c. Complex height a. D layer d. Critical height b. E layer 23. The highest frequency whereby a wave will c. F layer be returned back to earth by an ionospheric d. Vantress layer layer having been beamed up at it and 29. This phenomenon occurs when the thicker ranges from 5 to 12 MHz. For F2 layers. air is on top instead of being at the bottom This frequency is directly proportional to the when the temperature of water vapor secant function of the smallest angle, which gradient is lesser or greater than the standard allows reflection of sky waves. rate. a. Apex frequency a. Thermal inversion b. Critical frequency b. Horizontal ducting c. Carrier frequency c. Elevated ducting d. Baseband frequency d. Sporadic E 24. The distant at which sky-wave signals are 30. An ionospheric layer, which exists between reflected back to earth depend on 90 to 120 km above the earth’s surface and a. Height of the reflecting layer is about 25km thick. It aids MF surface b. The takeoff angle of the waves propagation while reflecting some HF c. Both a and b during daytime d. Conductivity of the soil a. D-layer 25. Perfect reflection of waves occur when b. E-layer a. The magnitude of the incident is c. F layer equal to the reflected waves d. Vantress layer b. The magnitude of the incident is less 31. Atmospheric condition is controlled by than the reflected waves a. Pressure c. The magnitude of incident is greater b. Temperature c. Humidity c. Dispersion d. All of these d. Multipath fading 32. This ionospheric layer forms at night at 38. The transfer of electromagnetic waves or about 300 km from the earth’s surface and is acoustical energy from one place to another responsible for long distance HF wave through a suitable transmission medium is propagation due to reflection and refraction. a. Wave propagation It splits during daytime due to the ionizing b. RF induction energy from ultraviolet rays of the sun. c. Radio Frequency Interference a. D layer d. Forward Scatter b. E layer 39. The upper limit of frequencies that can be c. F layer used at a specified time for radio d. Vantress layer transmission between two points and 33. When the transmitting and receiving involving propagation by reflection from antennas are line-of-sight of each other, the regular ionized layers of the ionosphere is mode of propagation is _____ wave. a. Maximum usable frequency a. Space or direct b. Optimum traffic frequency b. Sky c. Minimum usable frequency c. surface d. Carrier frequency d. ground 40. Waves whose oscillations are perpendicular 34. Power density is inversely proportional to to the direction of propagation are called the square of the distance from the source or a. Huygen’s waves transmitter to the destination or receiver. b. Transverse waves This law is called: c. Longitudinal waves a. Coulomb’s law d. Fraunhoffer waves b. Law of Universal Gravitation 41. Indicate which one of the following terms c. Inverse Square Law applies to troposcatter propagation: d. Lenz’s Law a. SIDs 35. A one-hop, full duplex, microwave system is b. Fading in a space diversity arrangement. Determine c. Atmospheric storms how many receivers in all are used? d. Faraday rotation a. 6 42. VLF waves are used for some types of b. 2 services because c. 8 a. Of the low power required d. 4 b. The transmitting antennas are of 36. ______is the extra ionization of the E- convenient size layer resulting to irregular and intermittent c. They are very reliable reflection of frequencies of up to 80 MHz in d. They penetrate the ionosphere easily temperate and lower latitudes of frequencies 43. High frequency waves are of up to 80MHz in temperate and lower a. Absorbed by the F2 layer latitudes. It is variable in time of occurrence, b. Reflected by the D layer height. Geographical distribution, c. Capable of use for long-distance penetration frequency and ionization communications on the moon density. d. Affected by the solar cycle a. Sporadic E 44. Distances near the skip distance should be b. Dillinger Effect used for sky-wave propagation c. Faraday rotation a. To avoid tilting d. Scintillations b. To prevent sky-wave and upper 37. The decrease in signal strength as a result of ray interference absorption or scattering of energy along a c. To avoid the faraday effect transmission path is called: d. So as not to exceed the critical a. Attenuation frequency b. Microbending 45. The ground wave ecentually disappears, as one moves away from the transmitter, b. Radio propagation because of c. Wave propagation a. Interference from the sky wave d. All of these b. Loss of line of sight conditions 52. Electromagnetic waves are c. Maximum single-hop distance a. Consist of electric and magnetic limitation component that are parallel to each d. Tilting other b. Oscillations that propagate through free space 46. In electromagnetic waves, polarization c. Irregular oscillations a. Is caused by reflection d. Oscillations that are produced by an b. Is due to the transverse nature of oscillating circuit the waves c. Results from the longitudinal nature of the waves d. Is always vertical in an isotropic 53. The region around an electrically charged medium body in which other charged bodies are 47. Radio fading resulting from obstruction acted by an attracting or repelling force. losses. a. Electric field a. Log normal fading b. Radiation field b. Rayleigh Fading c. Magnetic field c. Multi-path fading d. Electromagnetic field d. None of these 54. What are the two components of 48. The absorption of radio waves by the electromagnetic field? atmosphere depends on a. Ray and wavefront a. Their frequency b. Magnet and electricity b. Their distance from the transmitter c. Polar electrons and magnetic field c. The polarization of the waves d. Electric field (E-field) and d. The polarization of the atmosphere magnetic field 49. Electromagnetic waves are refracted when 55. Shows a surface of constant phase of a wave they and is formed when points of equal phase on a. Pass into a medium of different rays propagated from the source are joined dielectric constant together. b. Are polarized at right angles to the a. Ray direction of propagation b. Wavefront c. Encounter a perfectly c. Point source surface d. Isotropic source d. Pass through a small slot in a 56. It is a line drawn along the direction of conducting plane propagation of an electromagnetic wave 50. Diffraction of electromagnetic waves used to show the relative direction of a. Is caused by reflection from the electromagnetic wave propagation. ground a. Ray b. Arises only with spherical b. Wavefront wavefronts c. Point source c. Will occur when the waves pass d. Isotropic source through a large slot 57. Refers to the rate at which energy passes d. May occur around the edge of a through a given surface area in free space sharp obstacle a. Field intensity 51. What do you call of the travel of b. Power density electromagnetic waves through a medium at c. Refractive index the speed of light? d. Absorption coefficient a. RF propagation 58. It it’s the intensity of the electric and magnetic fields of an electromagnetic wave a. The ratio of velocity of light in free propagating in free space space to the velocity of light in a a. Field intensity given material b. Power density b. The ratio of the light in free space c. Refractive index towards the light in a given medium d. Absorption coefficient c. The ratio of the angle of refraction 59. In a lossless transmission medium, ______d. The amount of bending or refraction of free space is equal to the square root of that occurs at the interface of two the ratio of its magnetic permeability to its material of different densities electric permittivity a. Resistance b. Field intensity c. Characteristic impedance 66. Why is it that rays traveling near the top of d. A or C is correct the medium travel faster than those at the 60. Electromagnetic wave measures all except bottom? a. Inductance a. The medium is more dense near the b. Power density bottom c. Magnetic field intensity b. The medium is less dense at the top d. Permittivity of the medium c. A and B are incorporated 61. A reduction in power density due to the d. The medium is less dense near the inverse square law presumes free-space bottom and more dense at the top propagation is called 67. When does reflection if wave occur? a. Absorption a. When an incident wave strikes a b. Wave attenuation boundary of two media, and some of c. Space attenuation of the wave the incident power does not enter the d. B or C is correct second material 62. Which of the following are optical effects of b. When the reflective surface is radio waves? irregular or rough a. Refraction and reflection c. When two or more electromagnetic b. Diffraction and interence waves combine in such a way that c. Induction and diffraction the system performance is degraded. d. A and B d. A and B 63. What is diffraction? 68. What is meant by specular reflection? a. Is the change in direction of a ray as a. Is a reflection from a perfectly it passes obliquely from one medium smooth surface to another with different velocities or b. Is an incident wavefront striking an propagation irregular surface, randomly scattered b. Refers to the modulation or in many directions redistribution of energy within a c. Reflection of surfaces that fall wavefront when it passes near the between smooth and irregular edge of an opaque object d. Is a combination of diffused and c. Is the phenomenon that allows light semirough surfaces or radio waves to travel(peek) 69. ______states that a semirough surface around corners of an obstacle. will reflect as if it were a smooth surface d. A or C is right whenever the cosine of he angle of 64. A rare refracting medium has incidence is greater than 1/8d, where d is the a. Smaller value of dielectric constant depth of the surface irregularity and I is the b. Higher value of dielectric constant wavelength of the incident wave. c. Variable value for dielectric constant a. Rayleigh criterion d. A dielectric constant dependent on b. Huygen’s principle the medium c. Linear superposition 65. Refractive index refers to d. Reflection coefficient 70. Energy that has neither been radiated into d. Is not possible space nor completely transmitted 77. Way(s) of propagating electromagnetic a. Modulated waves waves: b. Captured waves a. Ground-wave propagation c. Standing waves b. Space wave propagation d. Incident waves c. Sky-wave propagation 71. What property of radio waves occurs d. All of these whenever two or more waves 78. At frequencies below 1.5 MHz, what simultaneously occupy the same point in propagation provides the best coverage? space? a. Ground wave a. Reflection b. Space wave b. Refraction c. Sky wave c. Diffraction d. All of these d. Interference 79. Which of these causes the wavefront to tilt progressively forward? a. Gradient density b. Electric field intensity 72. Pertains to a source which radiates equally c. Absorption coefficient in all directions d. Magnetic field intensity a. Isobaric source 80. Which of following of must be taken into b. Isotropic source consideration to ensure proper ground-wave c. Isentropic source propagation? d. Isothermal source a. Power 73. Electromagnetic waves travel at _____ in b. Terrain free space c. Frequency a. 300,000 km/sec d. B and C b. 200 km/sec 81. What are the applications of ground–wave c. 400,000 km/sec propagation? d. 100,000 km/sec a. Ship-to-ship and ship-to-shore 74. Any space or region wherein a magnetic communications force is exerted on moving electric charges b. Maritime mobile communications a. Electric field c. Radio navigation b. Radiation field d. All of these c. Magnetic field 82. The curvature of the earth presents a horizon d. Electromagnetic field to space wave propagation which is 75. Which of the following is a characteristic of approximately 4/3 that of the optical horizon electromagnetic wave? a. Standard atmosphere a. Measures power, voltage, b. Optical horizon capacitance and impedance of a c. Radio horizon system d. All of these b. Measures power density, voltage, 83. Refraction is caused by what factors? and inductance a. Changes in troposphere’s density and c. Measures power density, magnetic temperature field intensity, and electric field b. Water vapor content intensity c. Relative conductivity d. All of the above d. All of the above 76. Reflection waves 84. Any of the flowing can be caused to a. Should take place at one medium lengthen radio horizon: b. Does not necessarily take place at a. Elevating the transmit or receive one medium antennas above Earth’s surface c. Occurs at any other medium at the b. Elevating both antennas same time c. Installing the transmit and/or receive antennas on top of mountains or high a. D layer buildings b. E layer d. All of these c. F layer 85. A special condition which occurs when the d. G layer density of the lower atmosphere is such that 91. A layer in the ionosphere which is the most electromagnetic waves are trapped between important reflecting medium fir HF radio it and earth’s surface waves. It has 2 sublayers, at 90 to 250 mi a. Duct propagation height b. Sky wave propagation a. A layer c. Space wave propagation b. D layer d. Ground wave propagation c. E layer d. F layer

86. The vibrating electrons at the ionosphere 92. The apparent height og the ionized layer and decrease current which is equivalent to is always greater than the actual height reducing the dielectric constant, which in a. Critical height turn, will also cause the velocity of b. Virtual height propagation to______. c. Maximum height a. Increase d. Imaginary height b. Decrease 93. Refers to the shortest distance in which a c. Remain constant sky-wave signal will be returned to the d. Decrease by a factor of 2 earth. It includes the maximum ground-wave 87. Increasing the velocity of propagation range and the width of the skip zone. causes a/an _____ of the electromagnetic a. Hop waves. b. Skip distance a. Increasing refraction c. Actual distance b. Decreasing reflection d. Critical distance c. Increasing diffraction 94. Concerns to the highest frequency that is d. Decreasing interference able to return to earth when beamed at a 88. What layer has its maximum density at certain angle of incidence approximately 70 mi a noon, when the sun is a. Relative frequency at its highest point? b. Optimum frequency a. D layer c. Resonant frequency b. E layer d. Maximum usable frequency, muf c. Kennelly-Heaviside layer 95. In ______, the distant of each succeeding d. B or C hop from earth to ionosphere and back is 89. The sporadic E layer is a thin layer with a also the skip distance. very high ionization density. It is considered a. Hop transmission separately from the other layers and when it b. Single transmission appears, gives an unexpected improvement c. Unihop transmission in long distance radio transmissions. What d. Multihop transmission cause(s) its unpredictable appearance? 96. Concerns to the single reflection of a radio a. Sunspot activity wave form the ionosphere back to earth. b. Sunspot cycle a. Jog c. Solar flares b. Hop d. A and C c. Skip 90. The region in the ionosphere with a very d. Fading high ionization density at roughly 55 to 90 97. The fluctuation of signal strength at the miles and is used for frequencies up to about receiver that are caused by changes in the 20 MHz. It is gone completely at midnight. transmission medium a. Fading a. Biconical b. Hopping b. Horn c. Skipping c. Helical d. Diversity d. Discone 98. Gradual variation in the field strength of a 5. Indicate which of the following reasons for radio signal is compensated by using a counterpoise with antennas is false: a. Fading techniques a. Impossibility of a good ground b. Diversity techniques connection c. Transverse techniques b. Protection of personnel working d. Transmission techniques underneath 99. A modulation of two different RF carrier c. Provision of an earth for the antenna frequencies with the same IF intelligence, d. Rockiness of the ground itself then transmitting both RF signals to a given 6. One of the following is not a reason for the destination. use of an antenna coupler: a. Diversity a. To make the antenna look resistive b. Space diversity b. To provide the output amplifier with the c. Frequency diversity correct load impedance d. Polarization diversity c. To discriminate against harmonics 100.To increase the availability of the system, a d. To prevent reradiation of the local method in which the output of a transmitter oscillator is fed to two or more antennas that are 7. Indicate the antenna that is not wideband physically separated by an appreciable a. Discone number of wavelengths. b. Folded dipole a. Space diversity c. Helical b. Frequency diversity d. Marconi c. Polarization diversity 8. Indicate which one of the following reasons d. Space wave propagation for the use of an earth mat with antennas is false: a. Impossibility of a good ground COMMUNICATIONS ENGINEERING connection PART 6 b. Provision of an earth for the antenna ANTENNAS c. Protection of personnel working 1. An ungrounded antenna near the ground underneath a. Acts as a single antenna of twice the d. Improvement of the radiation pattern of height the antenna b. Is unlikely to need an earth mat 9. Show which of the following terms does not c. Acts as an antenna array apply to the Yagi-Uda array d. Must be horizontally polarized a. Good bandwidth 2. One of the following consists of nonresonant b. Parasitic elements antennas: c. Folded dipole a. The rhombic antenna d. High gain b. The folded dipole 10. An antenna that is circularly polarized is the c. The end-fire array a. Helical d. The broadside array b. Small circular loop 3. One of the following is very useful as a c. Parabolic reflector multiband HF receiving antenna. This is the: d. Yagi-Uda a. Conical horn 11. The standard reference antenna for the b. Folded dipole directive gain is the c. Log-periodic a. Infinitesimal dipole d. Square loop b. Isotropic antenna 4. Which of the following antennas is best c. Elementary doublet excited from a waveguide? d. Half-wave dipole 12. Top loading is sometimes used with an b. Hertz antenna in order to increase its c. Marconi a. Effective height d. Dipole b. Bandwidth 21. ______is a device that detects both c. Beamwidth vertically and horizontally polarized signals d. Input capacitance simultaneously. 13. Cassegrain feed is used with a parabolic a. Crystal reflector to b. Orthomode transducer a. Increase the gain of the system c. Light transducer b. Increase the beamwidth of the system d. Optoisolator c. Reduce the size of the main reflector 22. How much does the radiated power of an d. Allow the feed to be places at a antenna increases if its current increased by convenient point 3.3 times? 14. Zoning is used with a dielectric antenna in a. 6.6 times order to b. 3.3 times a. Reduce the bulk of the lens c. 10.89 times b. Increase the bandwidth of the lens d. 9.9 times c. Permit pin-point focusing 23. What do you call the energy that was not d. Correct the curvature of the wavefront radiated into space or completely from a horn that is too short transmitted? 15. A helical antenna is used for satellite a. Incident waves tracking because of its b. Captured waves a. Circular polarization c. Standing waves b. Maneuverability d. Modulated waves c. Broad bandwidth 24. What is the estimated medium wind loading d. Good front-to-back ratio in the Philippines for antenna tower design? 16. The discone antenna is a. 200 kph a. A useful direction-finding antenna b. 250 kph b. Used as a radar receiving antenna c. 300 kph c. Circularly polarized like other circular d. 100 kph antennas 25. The minimum number of turns a helix d. Useful as a UHF receiving antenna antenna must have 17. One of the following is not omnidirectional a. 4 antenna b. 5 a. Half-wave dipole c. 3 b. Log-periodic d. 6 c. Discone 26. When testing transmitter to prevent d. Marconi interfering with other stations, which type of 18. The polarization of a discone antenna is antenna must be used? ______. a. Dummy antenna a. Horizontal b. Herztian antenna b. Vertical c. None c. Omni d. Void antenna d. Directional 27. A device that radiates electromagnetic 19. ______is the horizontal pointing energy and/or intercepts electromagnetic angle of an antenna. radiation a. Right angle a. Antenna b. Angle of elevation b. Transmitter c. Bandwidth c. Transmission line d. Azimuth d. Transceiver 20. Which is a properly terminated antenna? 28. Determine the gain of a 6 ft parabolic dish a. Rhombic operating at 1800 MHz a. 15.5 dB c. Efficient and ideal radiated power b. 30 dB d. Effective isotropic radiated power c. 11.2 dB 38. Which of the following refers to the smallest d. 28.17 dB beam of satellite antenna’s radiation pattern? 29. Radiation characteristic of a dipole a. Global beam a. figure of eight b. Zoom beam b. omnidirectional c. Spot beam c. bi-directional d. Hemispheric beam d. unidirectional 39. A region in front of a parabolic antenna 30. An antenna which is not resonant at a. Transmission zone particular frequencies and so can be used b. Fraunhofer over a wide band of frequencies is called c. Fresnel a. Aperiodic d. All of these b. Cassegrain 40. An antenna that can only receive a television c. Top-loaded signal. d. Boresight a. Isotropic antenna 31. Two wires that are bent 90 degrees apart. b. Reference antenna a. Rhombic c. TVRO b. Hertz d. Yagi antenna c. Dipole 41. Radiation pattern of a discone d. Log-periodic a. Figure of eight 32. Harmonic suppressor connected to an b. Bi-directional antenna c. Omnidirectional a. Tank circuit d. Unidirectional b. M-derived filter 42. Radio wave concentration in the direction of c. Low-pass filter the signal emitted by a directional antenna. d. High-pass filter a. Back lobe radiation 33. Theoretical gain of a Herztian dipole b. Transmitted signal a. 0 dB c. Side lobe radiation b. 1.76 dB d. Major lobe radiation c. 2.15 dB 43. The reflector and director of an antenna d. 3 dB array are considered as: 34. A helical antenna is used for satellite a. Transcendental elements tracking because of b. Feed-points a. Maneuverability c. Driven elements b. Good front-to-back d. Parasitic elements c. Circular polarization 44. An electronic equipment used to measure d. Broad bandwidth standing wave ratio: 35. A convenient method of determining antenna a. Altimeter impedance b. Multimeter a. Reactance circle c. Reflectometer b. Stub matching d. Wavemeter c. Smith chart 45. The product of the power supplied to the d. Trial and error antenna and its gain relative to a half-wave 36. Unity gain antenna. dipole in a given direction. a. Half-wave dipole a. Rated power b. Rhombic b. ERP c. Dummy c. Peak envelope power d. Isotropic d. Carrier power 37. EIRP stands for ______. 46. What makes an antenna physicaly long a. Effective isotropic reflected power electronically short? b. Effective isotropic refracted power a. Adding C in series b. Top loading antennas stacked one above the other fed in c. Adding L in series phase? d. All of these a. 4 dB over the gain of one antenna 47. The capture area of an antenna is directly b. 10 dB over the gain of one antenna proportional to the c. 3 dB over the gain of one antenna a. Distance between transmitter and d. 6 dB over the gain of one antenna receiver 54. Gain of an isotropic antenna. b. Power density of the signal a. 1 dB c. Gain of the antenna b. -1 dB d. Frequency of the received signal c. 0 dB 48. A type of an underfrounded antenna is a/an d. 2 dB ______. 55. A dipole antenna requires to be fed with 20 a. Hertz kW of power to produce a given signal b. Isotropic strength to a particular distant point. If the c. Parabolic addition of a reflector makes the same field d. Marconi strength available with an input power of 11 49. What is meant by antenna gain? kW, what is the gain in dB obtained by the a. The ratio of the signal in the forward use of the reflector? (Gain referred to this direction to the signal in the backward particular dipole) direction a. 4. 75 b. The ratio of the amount of power b. 1.81 produced by the antenna compared to the c. 4.24 output power of the transmitter d. 2.6 c. The final amplifier gain minus the 56. Top loading is used in an antenna in order to transmission line losses (including any increase its ______. phasing lines present) a. Bandwidth d. The numeric ratio relating the b. Beamwidth radiated signal strength of an antenna c. Input capacitance to that of another antenna d. Effective height 50. It consists of a number of dipoles of equal 57. A horizontal antenna is size, equally spaces along a straight line with a. Perpendicularly polarized all dipoles fed in the same phase from the b. Centrally polarized same source. c. Horizontally polarized a. End-fire array d. Vertically polarized b. Yagi antenna 58. The frequency of operation of a dipole c. Log-periodic antenna antenna cut to length of 3.4 m. d. Broadside array a. 42.9 MHz 51. A type of array antenna which consists of b. 53.3 MHZ one half-wave driven dipole, one reflector c. 38.5 MHz and one director. d. 61.3 MHz a. Log periodic dipole array 59. Two or more antennas separated by 9 b. Yagi-uda wavelengths are used. c. Herztian dipole a. Frequency diversity d. Broadside collinear b. Space diversity 52. It is measure of the microwave power c. Hybrid diversity radiated from an antenna as a function of d. Polarized diversity angular direction from the antenna axis. 60. A convenient method of determining antenna a. Polarization impedance. b. Sidelobes a. Trial and error c. Beamwidth b. Stub matching d. Antenna pattern c. Smith chart 53. What is the gain of four identically polarized d. Reactance circle 61. Width measured in degrees of a major lobe antenna exist? between end of the lobe at which the relative a. At feed point power is one half (-3 dB) its value from the b. Near the feed point peak of the lobe. c. Near the center a. Radiation d. At center b. Wavelength 68. This is a flexible vertical rod antenna c. Bandwidth commonly used on mobiles. d. Beamwidth a. Hertz 62. An increase in the effective power radiated b. Ground plane by an antenna in a certain desired direction c. Whip at the expense of power radiated in other d. Marconi directions. 69. What is a dummy antenna? a. Antenna gain a. A non-directional transmitting antenna b. Antenna efficiency b. An antenna used for hand-held ratio c. Antenna total ratio c. One which is used as a reference for gain d. Antenna back lobe ratio measurements 63. Where does the maximum current and d. A non-radiating load for a transmitter minimum voltage value on a resonant Hertz used for testing dipole exist? 70. Best description of a collinear and broadside a. Center of the antenna antenna radiation pattern. b. Ends of the antenna a. Bidirectional c. Near the center of the antenna b. Omnidirectional d. Near the end of the antenna c. Unidirectional 64. How can the antenna efficiency of a HF d. Perfect circle grounded vertical antenna be made 71. What is a driven element of an antenna? comparable to that of a half-wave antenna? a. Always the forwardmost element a. By isolating the coax shield from ground b. Always the rearmost element b. By installing a good ground radial c. The element fed by the transmission system line c. By shortening the vertical d. The element connected to the rotator d. By isolating the coax shield from ground 72. Antenna which is not properly terminated 65. Known as the technique for adding a series a. Whip inductor at or near the center of an antenna b. Non-resonant element in order to cancel the capacitive c. Isotropic reactance of an antenna. d. Resonant a. Reflector 73. At the ends of a half-wave antenna, what b. Center loading values of current and voltage exist compared c. Dipole to the remainder of the antenna? d. Loading coil a. Minimum voltage and maximum current 66. What is meant by the term antenna b. Maximum voltage and minimum bandwidth? current a. The angle between the half-power c. Minimum voltage and minimum current radiation points d. Equal voltage and current b. The angle formed between two 74. Refers to a type of beam antenna which uses imaginary lines drawn through the ends two or more straight elements arranged in of the elements line with each other. c. The frequency range over which an a. Whip antenna antenna can be expected to perform b. Yagi antenna well c. Rhombic antenna d. Antenna length divided by the number of d. Dipole antenna elements 75. What is meant by the term radiation 67. Where does the voltage node of a half-wave resistance for an antenna? a. Losses in the antenna elements and feed d. Long wire antenna line 82. What measure will you adopt on the antenna b. An equivalent resistance that would system of a VHF or UHF mobile dissipate the same amount of power as transceivers that has very low height that radiated from an antenna antenna? c. The resistance in the trap coils to a. Increase transmitter to antenna cable received signal b. Use directional antenna d. The specific impedance of the antenna c. Check grounding system 76. Which of the following parts of the radio d. Provide loading coil receiver represents the component that 83. In order to have an effective radio antenna, extracts the desired RF signal from the the design of its radiator must have a electromagnetic wave? minimum length equivalent to a. Detector ______. b. Antenna a. λ/10 c. Crystal b. λ/4 d. AF amplifier c. λ/14 77. Determine the dB of a receiving antenna d. λ/6 which delivers a microvolt signal to a 84. What is a parasitic element of an antenna? transmission line over that of an antenna that a. An element dependent on the antenna delivers a 20 microvolt signal under identical structure for support. circumstances. b. A transmission line that radiates radio- a. -26 dB frequency energy. b. 26 dB c. An element that receives its excitation c. 3 dB from mutual coupling rather than d. 10 dB from a transmission line. 78. What is the term for the ratio of the radiation d. An element-polarized 90 degrees resistance of an antenna to the total opposite the driven element. resistance of the system? 85. At what position does a maritime ship main a. Antenna efficiency antenna have when it is open circuited and b. Radiation conversion loss that any auxiliary is/are connected to the c. Beamwidth main receiver? d. Effective radiated power a. AA 79. One of the following prevents a transmitter b. Emergency transmitter from emitting a signal that interferes with c. Direction finder other station on frequency during the test. d. Ground a. Use of shielded antenna radiator 86. Due to the presence of parallel LC networks b. Use of low height antenna in the trap antenna, one of the following is a c. Use of dummy antenna disadvantage of using this kind of antenna. d. Use of grounded antenna a. Radiate harmonics 80. In high frequency radio transmission, the b. Reduce power lower the radio frequency the c. Reduce beamwidth ______of the antenna. d. Allow entry of interference a. Longer the length 87. How do you compare the length of the b. Bigger the diameter reflector element of a parasitic beam antenna c. Shorter length with that of its driven element? d. Smaller the diameter a. Same length 81. Which of the following antenna where its b. Reflector element is 5% longer beamwidth is determined by the dimensions c. Reflector element is half shorter of its lens or reflector? d. Reflector element is 5% shorter a. Whip antenna 88. Which of the following statements refers to a b. Aperiodic antenna reason why intelligence signal cannot be c. Aperture antenna transmitted directly on their frequency? a. Their frequencies are high and are representing field strengths or power susceptible to noise densities at various angular positions relative b. Their frequencies are high and need very to an antenna? large antennas a. Venn diagram c. Their frequencies are low and need b. Figure-8 pattern very large antennas c. Lissajous figure d. Their frequencies are low and need very d. Radiation pattern small antennas 96. ______is the ratio of the front 89. What is the purpose of a certain antenna lobe power to the back lobe power. component composed of a parallel LC a. Front-to-side ratio networks inserted in the antenna called b. Front-to-back ratio traps? c. Back-to-front ratio a. Cancel the capacitive reactance of an d. Minor-to-major ratio antenna 97. It is defined as the area within a distance b. Enhance directivity D2/λ from the antenna, where λ is the c. Produce resonant system at specific wavelength and D is the antenna diameter in frequency the same units. d. Provide a multiband operation a. Far field 90. Refers to the numerical ratio relating to the b. Near field radiated signal strength of an antenna to that c. Green field of another antenna. d. Radiation field a. Antenna loss 98. What is the ratio of the power radiated by b. Antenna gain the antenna to the total input power? c. Antenna bandwidth a. Power gain d. Antenna efficiency b. Directive gain 91. How much longer or shorter does the length c. Antenna efficiency of the director element of parasitic beam d. Radiation efficiency antenna compared with that of the driven 99. ______of an antenna refers to element? the orientation of the electric field radiated a. About 5% shorter from it. b. Around 10% longer a. Radiation c. One half longer b. Bandwidth d. Around 5% longer c. Beamwidth 92. Refers to the ratio of radiated to reflected d. Polarization energy. 100. Pertains to a wire structure placed below the a. Front-to-back ratio antenna and erected above the ground. It is a b. Antenna efficiency form of capacitive ground system. c. Radiation efficiency a. Image d. Signal-to-noise ratio b. Counterpoise 93. A half-wave dipole antenna c. Antenna orientation a. Hertz d. Antenna polarization b. Marconi c. Parabolic d. Vertical monopole COMMUNICATIONS ENGINNERING 94. When conductors are spread out in a straight PART 7 line to a total length of one-quarter MICROWAVES wavelength, the antenna is called what? a. Marconi 1. Indicate which of the following frequencies b. Vertical monopole cannot be used for reliable beyond-the- c. Quarter-wave dipole horizon terrestrial communications without d. All of these repeaters: 95. What do you call of a polar diagram or graph a. 20 kHz b. 15 MHz wavelength of a signal c. 900 MHz b. Hollow metal tube used for d. 12 GHz transmission of microwave energy 2. A ship-to-ship communications system is c. Plastic tubular transmission line for plagued by fading. The best solution seems high RF network to be the use of d. Braided wire used for transmission of a. A more directional antenna HF b. A broadband antenna 10. Transmission lines which can convey c. Frequency diversity electromagnetic waves only in higher order d. Space diversity modes are usually called 3. A range of microwave frequencies more a. Coaxial cable easily passed by the atmosphere than are b. Twisted pair the others is called a c. Power lines a. Window d. Waveguides b. Critical frequency 11. In order to reduce cross-sectional c. Gyro frequency range dimensions, the waveguide to use is d. Resonance in the atmosphere a. Circular 4. Frequencies in the UHF range propagate by b. Ridge means of c. Rectangular a. Ground waves d. Elliptical b. Sky waves 12. A signal propagated in a waveguide has a c. Surface waves full wave of electric intensity change d. Space waves between the two farther walls, and no 5. Tropospheric scatter is used with component of the electric field in the frequencies in the following range: direction of propagation. The mode is a. HF a. TE1,1 b. VHF b. TE1,0 c. UHF c. TM2,2 d. VLF d. TE2,0 6. When microwave signals follow the 13. When a particular mode is excited in a curvature of the earth, this is known as waveguide, there appears an extra electric a. The Faraday effect component, in the direction of propagation. b. Ducting The resulting mode is c. Tropospheric scatter a. Transverse electric d. Iosnospheric reflection b. Transverse magnetic 7. Helical antennas are often used for satellite c. Longitudinal tracking at VHF because of d. Transverse electromagnetic a. Troposcatter e. None of these b. Superrefraction 14. The wavelength of a wave in a waveguide c. Ionospheric refraction a. Is greater than in free space d. The Faraday effect b. Depends on waveguide dimensions and 8. ______consists basically of a free space wavelength thin film strip in intimate contact with one c. Is inversely proportional to the phase side of a flat dielectric substrate, with a velocity similar thin-film ground plane conductor on d. Is directly proportional to the group the other side of the substrate. velocity a. Strip line 15. When electromagnetic waves are b. Lecher wire propagated in a waveguide, they c. Microstrip a. Travel along the broader walls of the d. Stub guide 9. Waveguide is a b. Are reflected from walls but not a. Device used to determine the travel along them c. Travel through the dielectric without barely touches the obstruction is called touching the walls a. Line of Sight d. Travel along the 4 walls of the b. Obstructed Path waveguides c. Grazing Path 16. When microwave signals follow the d. Crooked Path curvature of the earth, this is known as 23. What is the function of regenerative a. Faraday Effect repeater? b. Deducting a. To eliminate bias distortion c. Tropospheric Scatter b. To help in the loading of the telegraphs d. Ionospheric Reflection lines 17. A waveguide mode in which there is no c. To reduce required signal levels component of electric field in the direction d. To reshape the pulses after they have of propagation given in the British become distorted European standards. 24. A situation when there is no change in a. H-mode attenuation or “no gain, no loss” occurs b. E-mode when ______% of the first Fresnel c. TE mode radius clears a path obstruction in d. M-mode microwave systems. 18. The extra strength needed in order to assure a. 45% that enough signal reaches the receiving b. 60% antenna and must be made available to c. 75% compensate for fades; computed as the d. 85% difference between the received signal 25. ______are concentric circular strength and the threshold level zones about a direct path of a microwave a. Fade Margin signal called Huygen’s radiation center, b. Threshold Level forming an imaginary solid called an c. Noise Figure ellipsoid ______. d. RSL a. Temperature zone 19. The use of redundant system to reduce the b. Skip zone effects of multipath fading is c. Fresnel zone a. Combining d. Fraunhoffer zone b. Modulation 26. Waveguides are used mainly for microwave c. Multiplexing transmission because d. Diversity a. They depend on straight line 20. A profile graph of the microwave energy propagation path b. Losses are heavy at lower frequencies a. Shows the cross section of the earth’s c. They are bulky at lower frequencies surface d. No generator is powerful enough to b. Determines LOS or site technical excite them feasibility 27. A waveguide assembly that lets the radar c. Determines the actual clearance, transmitter and receiver share an antenna is antenna heights and system reliability called d. All of the preceding a. Translator 21. In locating microwave relay stations, the b. Diplexer systems designer must consider c. Flip-flop a. Terrain obstructions and reflection d. duplexer points 28. ______is a graph wherein the b. Site security and navigational hazards terrain in which the microwave beam c. Availability of power, water source and should traverse. accessible roads a. Topograph d. All of the above b. Radio path profile 22. A microwave path over which radio waves c. Fresnel graph d. Net path graph d. Scales 29. The Fresnel zone is the circular zone about 37. The dominant mode in a rectangular the ______path. waveguide. a. Reflected a. TEM b. Direct b. TE1,1 c. LOS c. TE1,0 d. Refracted d. TM1,1 30. The radius in the circular zone is in the first 38. The velocity of a resultant wave as it Fresnel zone when the reflected path is travels through the waveguide. ______longer than the direct path. a. Speed of light a. λ/2 b. Group velocity b. λ c. Phase velocity c. λ/4 d. Incident velocity d. λ/8 39. The principal mode for a circular 31. At ______of the first Fresnel zone is a waveguide. condition where there is no gain and no a. TE1,0 loss. b. TM2,0 a. 0.5 c. TE1,1 b. 0.6 d. TEM c. 0.7 40. A type of waveguide that reduces the d. 0.8 cutoff wavelength, increases bandwidth and 32. The weakest signal the receiver could allows for a variation of the characteristics accept to be considered satisfactory. impedance. a. Threshold a. Ridge b. Fade margin b. Rectangular c. RSL c. Tee d. NPL d. Twisted 33. The frequency band from 8 to 12 GHz is 41. The subscript which indicates the number known as the band. of λ/2’ s along the waveguide height. a. C a. m b. Ku b. n c. X c. a d. Ka d. b 34. The difference between the Received 42. The international equivalent of the TE Signal Level and the FM Improvement mode Threshold a. H a. System Gain b. E b. Noise Threshold c. Z c. Fade Margin d. TEM d. Reliability 43. The smallest free space wavelength that is 35. A Fade Margin of 28 dB has a reliability of just unable to propagate in the waveguide a. 99% under given conditions. b. 99.9% a. Guide c. 99.99% b. Phase d. 99.999% c. Cut-off 36. Topographical maps are used for d. Group microwave communications systems design 44. The characteristic wave impedance of a because ______are shown, thereby waveguide in the TE mode is ______that elevations are known. of the TM mode. a. Latitudes a. Equal to b. Longitudes b. Higher than c. Contour lines c. Lower than d. NOTA b. LASER 45. The following are methods of exciting c. Quantum mechanics waveguides except d. GaAs maser a. Slot coupling 54. Paramagnetic means ______b. Antennas magnetic c. Flanges a. Almost d. Direct coupling b. Fully 46. Higher order mode-waveguides are not c. Slightly used in practice because they have ______d. Electro cut-off frequencies. 55. Tuning the ruby maser is done by adjusting a. Low the ______to alter the energy level of b. High the ferrous chromium. c. Indeterminate a. Electric field d. Fixed b. Magnetic field 47. Indicate which of the following cannot be c. Pumping of electrons followed by the word “waveguide” d. Electromagnetic field a. Elliptical 56. To overcome the very narrow bandwidth in b. Flexible ruby maser, ______is used. c. Coaxial a. Magnetron d. Ridged b. TWT 48. A piston attenuator is a c. IMPATT diode a. Vane attenuator d. Gunn diode b. Waveguide below cut-off 57. The following are applications of masers c. Mode filter except d. Flap attenuator a. Radioastronomy 49. Which of the following waveguide tuning b. Radiotelescope components is not easily adjustable? c. Radar a. Screw d. ET communications b. Stub 58. A parametric amplifier is a device which c. Iris amplifies signal by varying the d. Plunger a. Resistance 50. Which of the following is not a waveguide b. Reactance termination component? c. Magnetic field a. Tapered pyramid d. Electric field b. Post 59. The following are parts of the parametric c. Tapered resistance card amplifier except d. Stepped resistance card a. Idling circuit 51. What microwave component can sample b. Pump circuit part of the power travelling through the c. Tuned circuit waveguide? d. Filter circuit a. Directional coupler 60. The number of cavities in a magnetron used b. Magic tee in practice. c. Circulator a. 4 d. Re-entrant cavity b. 6 52. The following are gases used for LASER’s c. 8 except d. 10 a. Helium 61. Changing the anode voltage to change the b. Neon velocity of the electrons in a magnetron c. Argon tube d. ruby a. Frequency pushing 53. Also known as the optical maser b. Frequency pulling a. Ruby maser c. Strapping d. Pumping c. 0.25 % 62. The lowest frequency that will propagate d. 00.975% through the waveguide while operating in a 69. What would be the ERP, in watts if the particular mode. transmitter output is 30 dBm and the a. Critical frequency transmission line loss is 20 dB and the b. Cut-off frequency antenna connected to it has a power gain of c. MUF 60 dB? d. UHF a. 10,000 watts 63. The mode of a waveguide where there is no b. 1000 watts component of magnetic field in the c. 100 watts direction of propagation d. 10 watts a. TE 70. Also referred to as the Transferred Electron b. TM Device c. H a. Magnetron d. TEM b. TWT 64. The following are slow wave structures c. Gunn diode used to retard the RF field in a TWT except d. APD a. Helix 71. Also known as the Esaki diode b. Attenuator a. Gunn c. Waveguide coupled cavity b. Tunnel d. NOTA c. IMPATT 65. A rectangular waveguide is 5.1 cm by 2.4 d. PIN diode cm. The cut-off frequency for the dominant 72. The following are negative resistance mode is amplifiers except a. 2.94 GHz a. Tunnel b. 6.25 GHz b. Gunn c. 664 MHz c. IMPATT d. 57.7 GHz d. PIN diode 66. Calculate the cut-off wavelength, the guide 73. Regarded as the oldest semiconductor wavelength and the characteristic device impedance of a circular waveguide whose a. Shottky Barrier diode internal diameter is 4 cm for a 10 GHz b. PIN diode signal propagated in it in the dominant c. Point contact diode mode. (kr=1.84) d. Triode a. 6.83 cm, 3 cm, 420ῼ 74. Also called the hot electron diode b. 3 cm , 6.83 cm, 420 ῼ a. PIN diode c. 6.83 cm, 3.34 cm, 420 ῼ b. ESBAR d. 6.83 cm, 3.34 cm, 338 ῼ c. APD 67. A wave is propagated in a parallel plane d. Gunn diode waveguide. The frequency is 6 GHz and the 75. Also called tunnel rectifiers plane separation is 3 cm. The cut-off a. Backward diode wavelength for the dominant mode, the b. Schottky barrier diode group and phase velocities are c. APD a. 5 cm, 166 Mm/sec,543 Mn/sec d. PIN diode b. 6 cm, 166 Mm/sec,543 Mn/sec 76. Varactors are variable ______diode. c. 6 cm, 543 Mm/sec,166 Mn/sec a. Reactance d. 5 cm, 543 Mm/sec,166 Mn/sec b. Capacitance 68. If the MTBF of a communication circuit is c. Inductance 20,000 hours and its MTTR is 5 hours, d. Resistance what is its unavailability? 77. Diodes designed to store energy in their a. 0.00025 capacitance during forward bias and b. 99.975% generates harmonics in the reverse bias. a. Step recovery c. Polarized b. Gunn d. Single frequency c. APD 87. The ruby laser differs from the ruby maser d. IMPATT in that the former 78. A cross between the TWT and the a. Does not require pumping magnetron in its operation b. Needs no resonator a. CFA c. Is an oscillator b. BWO d. Produces much lower powers c. EIA 88. The transmission system using two ground d. Twystron planes 79. The following are parts of a multicavity a. Microstrip klystron except b. Elliptical waveguide a. Buncher cavity c. Parallel wire line b. Catcher cavity d. Stripline c. Cathode 89. A BWO is based on the d. Attenuator a. Rising sun magnetron 80. The very first microwave transistors b. CFA a. GaAs FET c. Coaxial magnetron b. Si BJT d. TWT c. MIC 90. One of the following is unlikely to be used d. NOTA as a pulsed device 81. The most common microwave FET which a. Multicavity klystron is also known as the MESFET b. BWO a. Dual GaAs FET c. CFA b. Si BJT d. TWT c. MIC 91. A microwave tube amplifier uses an axial d. Schottky Barrier Gate magnetic field and a radial electric field 82. It looks like a shorter, thicker TWT a. Reflex klystron a. CFA b. Coaxial magnetron b. BWO c. TW magnetron c. EIA d. CFA d. Twystron 92. The attenuator is used in the TWT to 83. A Twystron is a hybrid combination of a. Help bunching a. TWT and Magnetron b. Prevent oscillation b. TWT and Klystron c. Prevent saturation c. TWT and Ubitron d. Increase gain d. TWT and gyrotron 93. The glass tube of a TWT may be coated 84. A multicavity klystron with interconnected with aquadag to multigap cavities a. Help focusing a. TWT b. Provide attenuation b. Twystron c. Improve bunching c. EIA d. Increase gain d. Gyrotron 94. The cavity magnetron uses strapping to 85. SAW propagate in a. Prevent mode jumping a. GaAs b. Prevent cathode back heating b. InP c. Ensure bunching c. Stripline d. Improve the phase focusing effect d. Quartz crystal 95. Compared with equivalent transmission 86. The output from a laser is monochromatic; lines, 3-GHz waveguides (indicate false this means that it is statement) a. Infrared a. Are less lossy b. Narrow beam b. Can carry higher powers c. Are less bulky channels are assigned on “as needed” basis. d. Have lower attenuation a. PAMA 96. Indicate the false statement. When the free- b. DAMA space wavelength of a signal equals the cut- c. SSMA off wavelength of the guide d. CDMA a. The group velocity of the signal 3. A form of CDMA where a digital code is becomes zero used to continually change the frequency of b. The phase velocity of the signal the carrier. becomes infinite a. Spread Spectrum c. The characteristic impedance of the b. Frequency Hopping guide becomes infinite c. Store and Forward d. The wavelength within the waveguide d. SPADE becomes infinite 4. The satellite frequency reuse method which 97. A disadvantage of microstrip with respect sends different information signals using to stripline circuits is that the former vertical or horizontal electromagnetic a. Do not lend themselves to printed- polarization. circuit techniques a. Multiple coverage areas b. Are more likely to radiate b. Dual polarization c. Are bulkier c. Spatial separation d. Are more expensive and complex to d. Spread spectrum manufacture 5. A satellite communication link between 98. In order to couple two generators to a Pinugay Earth Station, Philippines and Mt. waveguide system without coupling them Fucino Earth Station, Italy is to be to each other, one could not use a established. If the assigneduplink frequency a. Rat-race at Pinugay Earth Station is 6175 MHz, what b. E-plane T is the downlink frequency at Mt. Fucino c. Hybrid ring Earth Station, in MHz? d. Magic T a. 4545 99. A PIN diode is b. 3950 a. A metal semiconductor point-contact c. 3789 diode d. 4200 b. A microwave mixer diode 6. A satellite equipped with electronic devices c. Often used as a microwave detector to receive, amplify, convert and retransmit d. Suitable for use as a microwave signals. switch a. Passive 100. For handling high powers, the best b. Active transmission medium is c. Uplink a. Stripline d. Downlink b. Microstrip 7. “The orbit of any planet is an ellipse with c. Rectangular waveguide the sun at one focus”. This is d. Coaxial line a. Kepler’s First Law b. Kepler’s Second Law c. Kepler’s Third Law COMMUNICATIONS ENGINEERING d. Law of Universal Gravitation PART 8 8. The point in an satellite orbit which is SATELLITE COMMUNICATIONS farthest away from the earth 1. The first duplex satellite is a. Perigee a. Moon b. Apogee b. Sputnik 1 c. Azimuth c. Telstar d. Ascending node d. Early Bird 9. The first active satellite which transmitted 2. The FDMA technique wherein voice band telemetry information a. Telstar 1 a. Spot coverage b. Aguila II b. Zonal coverage c. Palapa A 1 c. Earth coverage d. Sputnik d. Regional coverage 10. The portion of the satellite communication 18. An earth station transmits signal to a link involving the transmission of traffic satellite 38,500 km., directly overhead it. from ground station to satellite. What is the propagation delay when the a. Uplink signal is received back at the same earth b. Lowlink station, in milliseconds. c. Paylink a. 257 d. Bus transmission b. 200 11. It is spacecraft places in orbit around the c. 285 earth carrying on-board microwave d. 185 receiving and transmitting equipment. 19. When a satellite orbits in the opposite a. Communication satellite direction as the earth’s rotation with an b. Terrestrial link angular velocity less than that of the earth. c. Transponder a. Bus transmission d. Microwave repeater b. Payload 12. Satellite position has an/a ______c. Prograde angle with respect to the horizon. d. Retrograde a. Azimuth 20. The actual user information conveyed b. Depression through the satellite system. c. Elevation a. Bus transmission d. Critical b. Payload 13. A satellite that revolves from North to c. Prograde South. d. Retrograde a. Equatorial 21. The spatial separation between b. Polar geosynchronous satellites c. Orbital a. 1 – 3 degrees d. Inclined b. 3 – 6 degrees 14. The Kepler’s Law which is also known as c. 6 – 8 degrees the Law of Areas. d. 8 – 10 degrees a. First Law 22. ______detects the satellite signal b. Second Law relayed from the feed and converts it to an c. Third Law electric current, amplifies and lower its d. None of the above frequency. 15. The satellite multiple access technique a. Feedhorn which uses the spread spectrum technology b. Satellite dish is c. Satellite receiver a. FDMA d. LNB b. TDMA 23. What kind of battery panels are used in c. CDMA some advance satellites? d. DAMA a. Gallium Arsenide solar panel 16. The point where the orbit crosses the b. Silicon based panels equatorial plane going from South to North. c. Germanium based panels a. Ascending Node d. Gallium Phosphate solar panel b. Descending Node 24. Footprint refers to coverage area in the c. Apogee globe d. Perigee a. Satellite radiation polarization 17. The footprint which covers approximately b. Satellite navigation one-third of the earth’s surface using a 17 c. Satellite radiation pattern degree beamwidth. d. Satellite coverage 25. Satellite system or part of a satellite system, c. Coordination boresight area consisting of only one satellite and the d. Effective boresight area operating earth station. 34. Refers to the man-made body sent into a. Satellite system continuous orbit around the earth, which b. Satellite network provides propagation paths for radio waves c. Space system between terrestrial transmitters and d. Multi-satellite link receivers. 26. Known to be the first satellite capable to a. Rocket receive and transmit simultaneously. b. Allotter relay a. Syscom I c. Space shuttle b. Echo I d. Communication satellite c. Telstar I 35. What is the basic function of a d. Score communications satellite? 27. A satellite receives an uplink frequency of a. To act as a receiving antenna for ______MHz from a ground station broadcast FM of 3700 MHz. b. To compensate for the antenna a. 8150 MHz limitations b. 1475 MHz c. To eliminate aerodynamic drag c. 2225 MHz d. To acts as receiving antenna for d. 5925 MHz broadcast AM 28. What band does VSAT first operate? 36. Typical round-trip distance and transmission a. X-band time for a satellite relay b. C-band a. About 300 ms and 90,000 km, c. Ku-band respectively d. L-band b. 90,000 km and about 300 ms, 29. Satellite engine use respectively a. Liquid fuel c. 90,000 mi and about 100 ms, b. Jet propulsion respectively c. Ion propulsion system d. 90,000 mi and 300 ms, respectively d. Solar jet 37. The figure of a satellite defines in orbit 30. The first passive satellite transponder a. Circle a. Early bird b. Elliptical b. Score c. Parabolic c. Moon d. Hyperbolic d. Sputnik 38. Considered as the corrupting influence(s) in 31. Satellite used for intercontinental the satellite movement. communications are known as a. Gravitational pill between the earth and a. Comsat the orbiting satellite b. Domsat b. Atmospheric drag on the satellite c. Marisat c. Orbital ellipse d. Intelsat d. All of these 32. AsiaSat 1 covers how many countries in 39. The orbit of communications satellites id Asia? defined by the angle with respect to the earth a. 38 equator, which is the 0o plane. What is (are) b. 40 the basic orbital angle(s)? c. 44 a. Polar d. 42 b. Inclined 33. An area on the surface of the earth within c. Equatorial which the boresight of the steerable satellite d. All of the above beam intended to be pointed. 40. How do we measure the position of a a. Equivalent boresight area satellite? b. Contour boresight area a. By its elevation angle with respect to the horizon a. To received signals for the GPS system b. By its azimuth angle measured from the four satellites, compute the clockwise from the direction of true distance differences, and determine north position c. Through the line of apsides b. To transmit time codes and orbital d. A and B are correct position information to the users 41. Which of the following cause(s) the c. To assure the overall performance and satellite’s orbital distortions? accuracy a. Sun d. All of the above b. Earth 48. How do you describe the complete signal c. Moon path of the satellite communications d. All of the above operation? 42. What is the approximate service life of a. Begins at a ground station, proceeds to communications satellites? an uplink, then to a downlink, and ends a. 3 years only at a receiving ground station. b. 5 to 20 years b. From the satellite, to a downlink, tehn to c. 20 to 60 years a ground station. d. 100 years c. Begins at a ground station, proceeds to 43. Representing application of the an uplink, to the satellite itself, to a extraordinary advances technology of downlink, and ends at a receiving satellites to solve the problem of accurate, ground station reliable, 26 hr/day navigation. d. All of these a. Global Positioning System (GPS) 49. What is a passive satellite? b. Navigation System using Timing and a. A satellite capable of receiving, Ranging (NAVSTAR) amplifying, and retransmitting c. A and B are correct information to and from earth stations. d. LORAN b. A bent-pipe or a reflector which 44. A system based on the accurate knowledge bounces a signal from one place to by the vessel of the position of each of four another. satellites, as calculated by the time with c. A satellite which receives transmissions respect to the user. from earth stations, stored them on a. GPS magnetic tape, and rebroadcast them to b. A or D ground stations farther along in its orbit. c. LORAN d. A or C d. NAVSTAR 50. How does communication between satellite 45. Segment(s) of a complete GPS system be achieved is(are) a. Using satellite cross-links a. Control segment b. Intersatellite links (ISLs) b. Space segment c. Through is ground stations c. User segment d. A or B is correct d. All of these 51. Which of the following refers to a delayed 46. Its function assures the overall system repeater satellite? performance and accuracy a. A satellite capable of receiving, a. Control segment amplifying, and retransmitting b. Space segment information to and from earth stations. c. User segment b. A bent-pipe or a reflector which bounces d. All of these a signal from one place to another. 47. The user segment is used to received signals c. A satellite which receives for the GPS system from the four satellites, transmissions from earth stations, compute the time differences, and determine stored them on magnetic tape, and position, while space segment’s function rebroadcast them to ground stations is(are) farther along in its orbit. d. All of these hr; and 2- 4 hr per orbit, respectively 52. Satellite orbiting in the same direction as c. 100 – 300 mi; 17,500 mi/hr; 1 ½ hr, earth’s rotation and at an angular velocity and ¼ or less per orbit, respective greater than the earth is called prograde d. 50 – 95 mi; 25,600 mi/hr, ½ hr; and 1/8 orbit; and a satellite orbiting which is in the or less per orbit, respectively opposite direction as Earth’s rotation or in 57. There are two primary classifications of the same direction but at an angular velocity communications satellite; one uses the less than that of Earth is known as angular momentum of its spinning body to a. Haley’s orbit provide roll and yaw relative to earth’s b. Elliptical orbit surface while an internal subsystem provides c. Equatorial orbit roll and yaw stabilization. What are they? d. Retrograde orbit a. gyroscopic satellites 53. Are satellites that orbit in a circular pattern b. delayed repeater satellites with an angular velocity equal to that of c. passive and active satellites earth. d. spinners and three-axis stabilizer a. Geostationary or geosynchronous satellites satellite 58. How do radiation patterns or beams from a b. Nonsynchronous satellite satellite antenna categorized? c. Orbital satellites a. Spot d. B or C is correct b. Earth c. Zonal d. All of these 54. What do you call of a satellite used to 59. A ______satellite with an orbital provide satellite services within a single period of one sidereal day or nominally, 24 h country? a. Bent-pipe satellite a. Orbital satellite b. Processing satellite b. Geostationary satellite c. Geostationary satellite c. Nonsynchronous satellite d. ANIK-D communications satellite d. Domestic satellite or domsat 60. 19,000 – 25,000 mi height; 6, 879 mi/hr 55. Which of the following is not an advantage travel time; 24-hr rotation; and 24-hr of geosynchronous orbit? availability time belong to what satellite? a. No need to switch from one satellite to a. Low-altitude satellites (circular orbit) another as satellites orbit overhead, b. Medium-altitude satellites (elliptical therefore, no breaks of transmission due orbit) to switching times. c. High-altitude satellites b. High-altitude geosynchronous satellites (geosynchronous orbit) can cover a much larger area d. GLONASS c. Geosynchronous satellites require 61. An orbit when the satellite rotates in a path higher transmit powers and more above the equator. sensitive receivers because of the a. Polar orbit longer distances and greater path loss. b. Inclines orbit d. Satellite remains almost stationary in c. Equatorial orbit respect to a given earth station, d. Geosynchronous orbit therefore, expensive tracking equipment 62. Orbiting satellite system in Russia which is not required at the earth stations. means “lightning” or “news flash”, used for 56. Which of the following parameters (height television broadcasting. It uses a highly of the satellite from earth, travel time, inclined elliptical orbit with apogee at about rotation period, and the satellite’s line of 40,000 km and perigee at about 1,000 km. sight) refer to low-altitude satellite? a. Molniya system a. 19,000 – 25,000 mi; 6,879 mi/hr; 24 hr; b. Molnya system and 24-h availability time, respectively c. Molnia system b. 6,000 – 12,000 mi; 12,189 mi/hr; 5 – 12 d. All are correct 63. Polar and inclined orbits refer to what? earth station antenna and the horizontal. a. Any other orbital path, and rotation b. The horizontal pointing of an antenna above the equator, respectively c. The angle subtended at the earth station b. Any other orbital path, and rotation that antenna between the satellite and the takes over the north and south poles, horizontal respectively d. A or C is right c. Rotation that takes over the north and 70. The range of frequencies used by south poles, and any other orbital communications satellites? path, respectively a. From 1 GHz up to 3 GHz d. Rotation above the equator, and rotation b. From 1 GHz up to 30 GHz that takes over the north and south poles, c. From 30 GHz up to 300 GHz respectively d. From 300 GHz up to 350 GHz 64. ______means the farthest distance 71. Otherwise considered as radio repeater in from earth a satellite orbit reaches while the sky. ______is the minimum distance. a. Transponder a. Apogee and perigee, respectively b. Satellite b. Perigee and apogee, respectively c. Sputnik c. A and B are the same d. Courier d. None of these 72. How does interference between uplink and 65. Refers to the line joining the perigee and downlink signals be prevented? apogee through the center of the earth a. By using different ground stations a. Line of sight b. By using different satellites b. Line of nodes c. By using different carrier frequencies c. Equatorial nelt d. All of these d. Line of apsides 73. An electronic system called transponder of 66. The point where the orbit crosses the the communications satellite is used equatorial plane going from north to south; a. For frequency translations and the point where the orbit crosses the b. To retransmit signals equatorial plane going from south to north c. To receive signals refer to d. All of the above a. Ascending node 74. What do you call of the signal path from the b. Descending node transmitter to satellite and from the satellite c. Ascending node and descending node, to earth-based receiver? respectively a. Downlink and uplink, respectively d. Descending node and ascending node, b. Downlink respectively c. Uplink and downlink, respectively 67. What is the line joining the ascending and d. Uplink descending nodes through the center of the 75. Why is it that the uplink is always higher in earth? frequency than the downlink? a. Line of apsides a. Because the uplink suffers greater b. Line of nodes spreading or free-space loss of frequency c. Line of shoot than its lower counterpart d. Line of sight b. Since an earth station aims upward with 68. Refers to the horizontal pointing of an well-controlled antenna sidelobes antenna. c. A and B are correct a. Look angle d. None of these b. Elevation 76. What is frequency hopping? c. Azimuth a. A form of CDMA where a digital code is d. Spot used to continually change the frequency 69. What is meant by the angle of elevation? of the carrier a. The angle formed between the direction b. Available bandwidth is partitioned into of travel of a wave radiated from an smaller frequency bands and the total transmission time is subdivided into d. Antennas smaller time slots 82. How do communications satellites c. Each earth stations within a CDMA powered? network is assigned a different a. By a bank of batteries whose charge is frequency hopping pattern in which each maintained by an array of solar cells transmitter hops or switched from one b. Liquid fuel frequency band to the next according to c. Nuclear their assigned pattern d. AC power d. All of these 83. ______is the total power 77. What is meant by satellite footprint? consumption for the satellite operation? a. Is the earth area that the satellite can a. About 10W receive from or transmit to b. About 150W b. Is the function of both the satellite orbit c. About 2000W and height, and the type of antenna the d. About 25000 W satellite uses. 84. As the height of a satellite orbits gets lower, c. The geographical representation of the the speed of the satellite satellite antenna’s radiation pattern. a. Increases d. All of the above b. Decreases 78. What (is)are the advantage(s) using 1-GHz c. Remains the same and higher frequencies? d. None of the above a. Large amount of information can be sent 85. The main function of a communications due to large available bandwidth satellite is the b. Propagation characteristics are very a. Repeater consistent b. Reflector c. Signal wavelengths are shorter c. Beacon d. All of these are correct d. Observation platform 79. What is meant by link budget? 86. The key electronic component in a a. The sum of all the signal gains and communications satellite is the losses along the way. a. Telemetry b. The difference of the signal gains and b. On-board computer losses along the way c. Command and control system c. Identifies the system parameters and is d. Transponder used to determine the projected C/N and 87. A circular orbit around the equator with a Eb/No ratios at both the satellite and earth 24-h period is called a(n) stations receivers for a given modulation a. Elliptical orbit scheme and desired Pq. b. Geostationary orbit d. A or C is right c. Polar orbit 80. How can satellite maintains its desired orbit d. Transfer obit consistently? 88. A satellite stays in orbit because the a. Using small on-board rocket trusters following two factors are balanced. b. Through using guidance system a. Satellite weight and speed c. By telemetry channel b. Gravitational pull and inertia d. All of these c. Centripetal force and speed 81. A satellite consists of any subsystem d. Satellite weight and the pull of the moon functions incorporated into a single system. and sun What is the subsystem responsible for 89. The height of a satellite in a synchronous providing the primary dc power and the equatorial orbit is regulated, secondary supply voltages for the a. 100 mi satellite circuits? b. 6800 mi a. Communication channel subsystem c. 22,300 mi b. Telemetry subsystem d. 35, 860 mi c. Power subsystem 90. Most satellites operate in which frequency band? d. They can’t a. 30 to 300 MHz 99. The typical bandwidth of a satellite band is b. 300 MHz to 3 GHz a. 36 MHz c. 3 GHz to 30 GHz b. 40 MHz d. Above 300 GHz c. 70 MHz 91. The main power sources for a satellite are d. 500 MHz a. Batteries 100. Which of the following is not usually a part b. Solar cells of a transponder? c. Fuel cells a. LNA d. Thermoelectric generators b. Mixer 92. The maximum height of an elliptical orbit is c. Modulator called the d. HPA a. Perigee b. Apex c. Zenith COMMUNICATIONS ENGINEERING d. Apogee PART 9 93. Batteries are used to power all satellite TELEPHONY subsystems 1. In International Telephone Numbering, a a. At all times digit or combination of digits characterizing b. Only during emergencies the called numbering area within a country c. During eclipse periods is called ______code. d. To give the solar arrays a rest a. Local 94. The satellite subsystems that monitors and b. CCITT controls the satellite is the c. Baudot a. Propulsion subsystem d. Area b. Power subsystem 2. The last two digits of the loaded cable c. Communications subsystem designation 22E66 indicates d. Telemetry, tracking, and command a. Spacing subsystem b. Coil inductance 95. The basic technique used to stabilized a c. Wire gauge satellite is d. Attenuation a. Gravity-forward motion balance 3. A condition of a telephone handset, in which b. Spin it can be called, is ______condition. c. Thrusters control a. On-hook d. Solar panel orientation b. Off-hook 96. The jet thrusters are usually fired to c. Busy a. Maintain altitude d. None of these b. Put the satellite into the transfer orbit 4. When digits 3 is dialled using touch tone c. Inject the satellite into the system, the amount of time needed to send geosynchronous orbit the tone is d. Bring the satellite back to the earth a. 0.1 sec 97. Most commercial satellite activity occurs in b. 50 msec which band(s)? c. 0.25 sec a. L d. 0.25 sec b. C and Ku 5. A telephone number perform the following c. X operations except d. S and P a. To route the call 98. How can multiple earth stations share a b. To activate the necessary apparatus for satellite on the same frequencies? proper call charging a. Frequency reuse c. To order clearing of connection b. Multiplexing d. None of the above c. Mixing 6. The number to be dialled or called to reach a subscriber in the same local network or No. 1 is ______. numbering area is a. 100 kHz a. Local code b. 102 kHz b. Area code c. 108 kHz c. Toll access code d. 60 kHz d. Subscriber No. 14. In the FDM hierarchy, a mastergroup is 7. That part of the telephone network between composed of ten supergroups and is the telephone instrument at the subscriber equivalent to premises and the central office equipment is a. 600 channels called the ______. b. 60 channels a. Inter-office trunk c. 180 channels b. Tie line d. 120 channels c. Subscriber loop 15. The approximation process in PCM creates d. Service drop wire noise called: 8. A line linking telephone central offices is a. Thermal called ______line. b. White noise a. Tie c. Quantizing noise b. Inter-office trunk d. Agitation noise c. Routing 16. The criteria to be considered in designing a d. Connector telephone system 9. A signalling technique wherein a number of a. Attenuation limit voice paths is carried over one common b. Resistance limit channel instead of having individual voice c. A or B channels. d. A and B a. In band signalling 17. This refers to loop AC reference frequency b. Out of band signalling measured in decibels c. Common channel signalling a. Signalling limits d. Alternate channel signalling b. Resistance limits 10. ______is a unit of telephone traffic c. Attenuation limits defined as one user making a call of ine d. All of these second duration. 18. An inuction coil which is multiple winding a. CCS transformer intended to interface a 2-wire b. Call-second circuit to be a 4-wire circuit to permit two- c. Erlangs way transmission of signals. d. Call-hour a. Hybrid function 11. During a busy hour in a telephone system an b. Speech transformer average of one call is lost, then the grade of c. Transmission regulation circuit service is considered to be: d. A or B a. 1.01 19. A subscriber loop signalling method in b. 10% which signalling information is indicated by c. 0.10% the presence and absence of a battery and d. 0.01 ground condition on the line at the called 12. If a busy counts are made during the span of end of the trunk. 15 minutes, and the average number of a. Wet- Dry occupied circuit is found to be 8, then the b. Reverse Battery traffic, in Erlang, is: c. High- Low a. 2 d. Supervisory b. 8 20. An arrangement where the only possible c. 6 connection between a number of exchanges d. 4 is through a single tandem or transit 13. In a standard CCITT group, 12 channels exchange where they are all connected. FDM, the carrier frequency of the channel a. Mesh b. Star b. 35 db c. Composite c. 15 db d. Ring d. 20 db 21. CCITT recommendation E-161 recommends 29. dBa is a noise unit which uses a tone of that not more than ______digits make up 1000 Hz and a power level of an international number, excluding the a. -85 dBm international prefix. b. -90dBm a. 10 c. 85dBm b. 12 d. -80dBm c. 16 30. The average intensity in one or more traffic d. 20 paths occupied in the busy hour by one 2- 22. The following are the transmission media minute call for an aggregate duration of two used for telephone systems except: minutes. a. Parallel wire a. CCS b. Coaxial wire b. Cm c. Fiber optics c. Erlang d. NOTA d. EBHC 23. The subscriber loop provides the following 31. A method of handling lost calls wherein a except: call failing to immediately find a server, a. Talk battery waits enters a queue until one becomes b. Ringing voltage available. c. Telephone dial a. Lost Calls Cleared d. Current during on hook b. Lost Calls Held 24. A method of multiplexing in which the total c. Lost Calls Delayed frequency spectrum available is used by d. NOTA each channel, but not part of the time. 32. The main terminal used as cross connection a. FDM point for cables 300 pairs and above. b. TDM a. MTTC c. SDM b. MDF d. GSM c. DP 25. The primary cause of echo and singing is d. TTC a. Intermodulation noise 33. For PCM, the sampling theorem states that b. Crosstalk the sampling frequency must be ______c. Impedance mismatch the highest frequency contained in the d. Thermal noise analog signal. 26. For crosstalk to be considered intelligible, at a. twice least ______words are intelligible to the b. more than twice listener in a seven second period. c. less than twice a. 5 d. equal to b. 6 34. a group of sixty voice channels with c. 4 bandwidth of 240 kHz is called a d. 3 a. group 27. Noise that is non-continuous, consisting of b. supergroup irregular pulse or noise spikes of short c. mastergroup duration and of relatively high amplitude. d. jumbogroup a. Solar 35. On the subscriber’s telephone set employing b. Intermodulation the touch tone technique, how many signals c. Impulse are transmitted to the telephone exchange d. Crosstalk for every button that is pressed? 28. The signal to noise ratio for voice based on a. 2 VHF signals customer satisfaction is b. 1 VHF and 1 AF a. 30 db c. 2 AF tones d. 16 AF tones rerouted into a preassigned station is called 36. An electronic circuit which is inserted into ______. the 4-wire trunk path effectively to block the a. Camp-On passage of reflected signal energy b. Call Forwading a. Echo suppressor c. Call Barring b. Loading coil d. Abbreviated Dialing c. Loop extender 44. What type of control system crossbar d. Telephone amplifier switches are operating? 37. The following are signalling functions a. Manual except: b. Progressive a. Ringing signals c. Common b. Address signals d. Automatic c. Supervisory signals 45. PABX stands for d. NOTA a. Private All-purpose Broadcasting 38. The standard spacing for 19-D-88 cable Exchange loading code is b. Private Automatic Branch Exchange a. 700 ft. c. Public Access Bidirectional Exchange b. 6000 ft d. Public Address Broadcasting Exchange c. 4500 ft 46. A trunk is d. 3000 ft. a. The base of a communication tower 39. A telephone exchange has a subscriber loop b. A telephone line connecting two C.O.’s limit of 1800 ohms, excluding the telephone c. A line connecting one telephone set to instrument. What is the farthest distance, in the PABX miles, that a subscriber can be located away d. The structure where antenna are attached from the telephone exchange, if AWG 26 47. The voice frequency channel pass band is: cable, which has a resistance of 431 a. 0 to 4000 Hz ohms/loop mile, is used? b. 300 to 3000 Hz a. 5.95 c. To carry only speech b. 8.18 d. All of the preceding c. 3.9 48. What is used to transmit more than one d. 4.18 conversation over a path? 40. The Strowger or step-by-step system falls a. Hybrid under what type of switching control b. Tandem system? c. Multiplexing a. Manual d. All of the above b. Progressive 49. The common channel interoffice signalling c. Common method d. Automatic a. Uses the same channel for signalling as 41. For building telephone facilities, the size of for the related conversation entrance conduit shall not be less than b. Is used on local loops ______in diameter. c. Uses a separate channel for signalling a. 30 mm only b. 50 mm d. Comes the signalling for one related c. 60 mm conversation d. 75 mm 50. Telephone switching is accomplished by 42. In telephony, tone dialing takes ______a. Manual Switchboard time than pulse dialing. b. Step-by-step Switches a. Less c. Crossbar switches b. More d. Any of the preceding c. About the same 51. The step-by-step switch d. Can’t be determined a. Was invented by Strowger 43. A telephone service wherein calls are b. Generates much noise c. Operates using a system of 59. The following are the building blocks of a electromechanical switches Step-by-step Switching System except: d. All of these a. Marker 52. The telephone was invented by b. Linefinder a. James Watson c. Selector b. Alexander Graham Bell d. Connector c. Phillip Reis 60. Which has longer subscriber loop length, the d. Almon Strowger Central Office Switching equipment having 53. A switching network capable of providing a a resistance limit of path from every inlet link to every outlet a. 5000 ohms link in the absence of traffic. b. 1000 ohms a. Concentration c. 1500 ohms b. Blocking d. 2000 ohms c. Full availability switch 61. A fax transmission is usually at a ______d. Crosspoint mode. 54. An exchange primarily used as a switching a. Simplex point for traffic between other exchanger is b. Half duplex a. Transfer system c. Full duplex b. Transit Exchange d. Multiplex c. Connecting point 62. A permanent circuit for private use within a d. Tandem Exchange communications network 55. A telephone switch is an example of a. Two-wire ______switching b. 4-wire a. Packet c. Switched b. Message d. Leased c. Circuit 63. The class of exchange with the primary d. Virtual circuit function of connecting central offices when 56. The local loop of a telephone system is a direct trunk is not available a. A two –wire communication circuit a. Local between a customer’s premise and the b. Gateway central office c. Toll b. A group of wires connecting a telephone d. Tandem set to a modem 64. Dial tone, busy tone and ring back tones are c. A four wire circuit connecting a fax example of ______signals. machine to a computer a. Supervisory d. A single piece of wire connecting the b. Address subscriber’s telephone to another c. Musical telephone set. d. Digital 57. Identical telephone numbers in different 65. How much time in seconds is saved if we parts of the country are distinguished by use Touch Tone Dialing instead of Pulse their Dialing to call telephone number 781-10- a. Access codes 05? b. Country codes a. 3.55 c. Trunk prefixes b. 7.75 d. Area codes c. 7.55 58. A telephone switching system with a d. 7.15 capacity of 100 lines could assign telephone 66. With attenuation limit at 6 dB, what is the numbers from length of cable using gauge 26 with a. 0001 – 1000 attenuation of 1.61 dB per km. b. 000- 999 a. 1.3 km c. 0000 – 1000 b. 4.7 km d. 001 – 999 c. 3.7 km d. 2.5 km cables over areas accessible to pedestrians is 67. The maximum length for 1300-ohm a. 4.5 m signalling or loop resistance using AWG No. b. 5.5 m 26 wire with 133.9 ohm per km. c. 3.5 m a. 5.2 km d. 6.5 m b. 4.7 km 76. The steel gauge of the outdoor MTTC c. 7.5 km a. 16 d. 9.7 km b. 18 68. The minimum size for an entrance conduit c. 20 for building telephone facilities. d. 22 a. 50 mm 77. PAM is: b. 50 cm a. A pulse system immune from noise c. 65 mm b. A digital system d. 65 cm c. A popular system for telephone 69. The size of entrance conduit for a 100 pair transmissions entrance cable. d. An analog system a. 50 mm 78. A suitable sampling rate for a signal b. 65 mm containing frequency components between c. 75 mm 40 Hz and 4 kHz would be: d. 100 mm a. 10 kHz 70. The backboard color for the house or riser b. 80 Hz cable c. 90 Hz a. Yellow d. 4.04 kHz b. White 79. Quantization noise can be reduced by: c. Blue a. Taking samples at a faster rate d. Red b. Using a PCM system 71. The maximum span from telephone pole to c. Increasing the number of standard the building for an aerial entrance cable. amplitude a. 30 m d. Using higher amplitude signals b. 600 mm 80. The name of the device invented by Johann c. 45 m Philipp Reis in 1860 which could transmit a d. 5.5 m musical tone over a wire to a distance point. 72. The sampling period for telephone signals a. Harmonic telegraph a. 8000 Hz b. Phonograph b. 125 usec c. Telephone c. 6400 Hz d. Radio d. 100 usec 81. When was the first complete sentence ever 73. The inability to interconnect two idle lines transmitted by the telephone? connected to a switching network due to all a. 1860 possible paths are in use b. 1876 a. Concentration c. 1892 b. Blocking d. 1905 c. Full availability 82. Who invented the first practical system for d. Crosspoint the electrical switching of calls installed in 74. The minimum depth for an underground 1892? entrance conduit under areas used for a. Bell vehicular traffic inside private property b. Watson a. 300 mm c. Edison b. 600 mm d. Strowger c. 50 mm 83. What part of the conventional telephone set d. 1 m transmitter and receiver unit are located? 75. The minimum clearance for aerial entrance a. Dial b. Base b. 200 – 3.3 kHz c. Keypad c. 20 – 20 kHz d. Handset d. 30 – 30 k Hz 84. The type of transmitter widely used in the 92. The signal heard on the telephone line that conventional telephone set. indicates readiness of the central office in a. Carbon receiving address or telephone number. b. Ceramic a. Dial tone c. Piezoelectric b. Ringing tone d. Electromagnetic c. Busy tone 85. Who invented the first carbon type d. Congestion tone transmitter? 93. The signal heard on the telephone line which a. Bell indicates that the called subscriber set is in b. Watson use. c. Gray a. Dial tone d. Edison b. Ringing tone 86. The type of receiver widely used in the c. Busy tone conventional telephone set d. Congestion tone a. Electromagnetic 94. BORSCHT stands for b. Ceramic a. Battery, over-voltage protection, c. Carbon ringing, supervision, coding, hybrid d. Piezoelectric and testing 87. How many unique tones are used for the 12- b. Battery, over-hook regulator, ringing, key dual-tone multifrequency keypad? surge protect, circuit, hybrid and test a. 2 c. Name of the leading manufacturer of b. 4 telephone system c. 7 d. Acronym for the developers of computer d. 12 95. Request for service from the telephone is 88. In the telephone industry, BORSCHT detected at the Central Office as functions are performed by a. Dial pulses a. Subscriber line interface b. Ringing signal b. Cross point matrix c. Flow of loop current c. Switching network d. Battery reversal d. Connector switch 96. The location where all subscriber lines are 89. In the telephone unit, what is produced when terminated and switching equipment facility the balancing network in a hybrid circuit is is installed. intentionally unbalanced slightly so that a. Central office small amount of transmitted signal is fed to b. Toll office the receiver of the talking phone? c. Gate way a. Dial tone d. Tandem b. Side tone 97. A private line communications channel of c. Echo the type provided by communication d. Singing common carrier for linking two or more 90. The type of dialing possible for telephone points together. set with rotary dial. a. Party line a. Tone dialing b. Tie line b. Pulse dialing c. DID line c. Loop dialing d. Trunk line d. E & m dialing 98. The attenuation loss limit of the subscriber 91. What is the standard bandwidth of voice loop is set at 6 dB. What is the maximum channel according to CCITT length if a 26H88 loading coil with an recommendations? attenuation of 0.80 dB per kilometre is a. 300 – 3.4 kHz added? a. 1.5 km b. 3.5 km c. 5.5 km d. 7.5 km 99. The first number of the loaded cable designation 19H44 indicates a. Spacing b. Coil inductance c. Wire gauge d. Attenuation 100. The letter of the loaded cable designation 24B88 indicates a. Spacing b. Coil inductance c. Wire gauge d. Attenuation

MULTIPLE CHOICE QUESTIONS

IN

ELECTRONICS SYSTEMS AND TECHNOLOGIES (EST)

Digital and Data Communications

MELVIN C. ARCEO, ECE PERC DC ENCODED BY: BADILLO, AIMIE E. 2006105942 ECE003/C11 1. It is defined as knowledge or intelligence that is d. All of these communicated between two or more points. 14. a. Carrier 15. The FDM telephone systems accommodate b. Sideband many channels by c. Information a. Increasing the multiplexer size d. Broadband b. Using many final carriers 2. c. Narrowing the bandwidth of each 3. What is the category of data transmission if d. Using multiple levels of the binary pulse is maintained for the entire multiplexing bit time? 16. a. Return to zero 17. It is the transmittal of digitally modulated b. Bipolar analog signals (carrier) between two or more c. Unipolar points in a communications system. d. Non – return to zero a. Digital modulation 4. b. Digital transmission 5. Which medium is the most widely used in c. Data communications LANs? d. Pulse modulation a. Twin Lead 18. b. Fiber – optic cable 19. Indicate which of the following systems is c. Twisted Pair digital. d. Coax a. Pulse-position modulation 6. b. Pulse-code modulation 7. These are used for transmission of PCM c. Pulse–width modulation encoded time – division multiplexed digital d. Pulse-frequency modulation signal. 20. a. I carriers 21. Classification of protocol that interprets a b. E carriers frame of data as a group of successive bit c. A carriers combined into predetermined pattern of d. T carriers fixed length, usually 8 bits each. 8. a. Character-oriented protocols 9. Which of the following is not a typical FDM b. Byte-oriented protocols application? c. Bit-oriented protocols a. Telemetry d. Character and Byte-oriented b. Stereo broadcasting protocols c. Telephone 22. d. Secure communications 23. Dividing the data block by a constant 10. produces a remainder that is used for error 11. A LAN device that is used to interconnect detection. It is called the two networks that use different protocols a. Vertical redundancy check and formats. b. Horizontal redundancy check a. Gateways c. Block check character b. Routers d. Cyclic redundancy check c. Bridges 24. d. Hubs 25. Which of the following is not a benefit of 12. spread spectrum? 13. A pulse modulation technique as the width a. Jam – proof of a constant amplitude pulse is varied b. Security proportional to the amplitude of the analog c. Immunity of fading signal at the time the signal is sampled. d. Noise proof a. Pulse Width Modulation 26. b. Pulse Length Modulation 27. c. Pulse Duration Modulation 28. Converting analog signals to digital is done by sampling and ______. 41. a. Quantizing 42. Start and stop bits, respectively, are b. Companding a. Mark, space c. Pre – emphasis b. Space, mark d. Mixing c. Space, space 29. d. Mark, mark 30. It is a process of converting an infinite 43. number of possibilities to a finite number of 44. It is the processing of analog signals using conditions. digital methods and includes band limiting a. Sampling and signals with filters, amplitude b. Coding equalization, and phase shifting c. Quantization a. Digital communications d. Aliasing b. Digital Signal Processing 31. c. Data communications 32. In T1, it is equal to the reciprocal of the d. Carrier recovery method sample rate 45. a. Slot Time 46. It is a network access method used primarily b. Transmission time with LANs configured in a ring topology c. Frame time using either baseband or broadband d. Bit rate transmission formats 33. a. Ethernet 34. What is the final output of a multiplexer? b. Token passing a. Baseband c. Token ring b. Composite baseband d. Token bus c. Information 47. d. Composite carrier 48. A small telephone switching system that can 35. be used as a LAN is called 36. The baud rate a. Ring a. is always equal to the bit transfer rate b. WAN b. is equal to twice the bandwidth of c. UART an ideal channel d. PBX c. is not equal to the signaling rate 49. d. is equal to one – half the bandwidth 50. The most common method used for of an ideal channel sampling voice signals in PCM systems 37. a. unnatural sampling 38. Bit errors in data transmission are usually b. flat top sampling caused by c. natural sampling a. equipment failures d. free sampling b. typing mistakes 51. c. noise 52. In PCM, it converts the PAM sampled to d. poor S/N ratio at receiver parallel PCM codes 39. a. Analog-to-Digital converter 40. A digital modulation technique which is a b. Digital-to-analog converter form of constant – amplitude angle c. Pre-emphasis circuit modulation similar to standard frequency d. Compander modulation except the modulating signal is 53. binary signal that varies between two 54. The OSI layer that provides the control discreet voltage levels. functions necessary to establish, manage and a. QAM terminated the connections as required to b. ASK satisfy the user request. c. PSK a. Application layer d. FSK b. Network layer c. Session layer limited numbers of output phase possible. d. Physical layer a. ASK 55. b. PSK 56. In PAM demultiplexing, the receiver clock is c. FSK derived from d. QAM a. standard radio station WWV 69. b. a highly accurate internal oscillator 70. The main circuit in a PSN generator is ____. c. the PAM signal itself a. XOR d. the 60 Hertz power line b. Multiplexer 57. c. Shift register 58. It is also known as digital modulation d. Mixer a. Digital transmission 71. b. Digital sampling 72. The circuit that performs demultiplexing in c. Digital radio an FDM system is _____. d. Data transmission a. Op - Amp 59. b. Bandpass filter 60. Time – division multiplex c. Discriminator a. can be used with PCM only d. Subcarrier oscillator b. combines five groups into 73. supergroup 74. ______defines how a user gets control c. stacks 24 channels in adjacent of the channel so as to allow transmission. frequency slots a. channel access d. interleaves pulses belonging to b. collision detection different transmissions c. collision avoidance 61. d. carrier sense 62. It is a numerical indication of how 75. efficiently a PCM code is utilized 76. The fastest LAN topology is the a. Coding efficiency a. ring b. Companding b. bus c. Pre-emphasis c. star d. Dynamic Range d. square 63. 77. 64. Type of PCM which is designed to take 78. It is a the symmetrical expectation of the bit advantage of the sample-to-sample error rate in the system redundancies in the typical speech a. probability of errors waveform b. error detection a. Single – bit PCM code c. error control b. Pulse Code Modulation d. bit error rate c. Differential PCM 79. d. Delta modulation 80. It is simply the data rate at which serial 65. PCM bits are clocked out of the PCM 66. The Basic Rate Interface (BRI) of ISDN has encoder onto the transmission line. a total bit rate of _____. a. line speed a. 192 kbps b. baud rate b. 148 kbps c. output rate c. 64 kbps d. bit rate d. 1.544 Mbps 81. 67. 82. A quantizing is ______. 68. A form of angle – modulated, constant a. Multiplexer amplitude digital modulation similar to b. Demultiplexer conventional phase modulation except its c. A/D converter input is binary digital signal and there are d. D/A converter 83. the delta modulator can maintain 84. Refers to the rate of change of a signal on a a. overload distortion transmission medium after encoding and b. granular noise modulation have occurred c. slope overload a. baud rate d. peak limiting b. phase shift 96. c. bit rate 97. A scheme in which several channels are d. frequency deviation interleaved and then transmitted together is 85. known as 86. The magnitude difference between adjacent a. Frequency division multiplex steps in quantization is called ______. b. Time division multiplex a. Quantum c. a group b. Step size d. a supergroup c. Resolution 98. d. Any of these 99. The best frequency demodulator is the 87. a. PLL discriminator 88. It is a set of rules implementing and b. Pulse-averaging discriminator governing an orderly exchange of data c. Foster-Seeley discriminator between layers of two devices, such as line d. Radio detector control units and front – end processors. 100. a. Data Link Protocol 101. What property distinguishes digital b. Network Protocol radio systems from conventional analog c. Point to Point Protocol communications system? d. File Transfer Protocol a. the type of carrier used in the 89. transmission of data 90. A signaling system in which each letter of b. the nature of the modulating signal the alphabet is represented by a different c. the type of modulation of data to be symbol is not used because used a. it would be too difficult for an d. the nature of the transmitter and operator to memorize receiver to be used b. it is redundant 102. c. noise would introduce too many 103. The circuit switch is a ______errors switch. d. too many pulses per letter are a. See – through required b. Transparent 91. c. Vague 92. A modulation process that involves d. Opaque conversion of a waveform from analog to 104. digital form by means of coding. 105. A carrier recovery is needed with a. PDM a. FSK b. PCM b. BPSK c. PLM c. DPSK d. PAM d. QAM 93. 106. 94. What is the bandwidth required to transmit 107. The Hartley – Shannon theorem sets at a rate of 10 Mbps in the presence of a 28- a limit on the bd S/N ratio? a. highest frequency that may be sent a. 1.075 MHz over a given channel b. 10 Mhz b. maximum capacity of a channel c. 5 Mhz with a given noise level d. 10.5 Mhz c. maximum number of coding levels 95. The slope of the analog signal is greater than in a channel with a given noise level d. maximum number of quantizing 121. levels in a channel of a given 122. Which of the following is not bandwidth primarily type of data communications? 108. a. a telephone 109. The phase relationship between b. teletype signaling elements for BPSK is the optimum c. telegraph signaling format and occurs only when two d. CW binary signal levels are allowed and when 123. one signal is the exact negative of the other. 124. Packets which is self – contained and a. Antipodal signaling travels through the network independent of b. Carrier recovery other packets of the same message by c. Squaring loop whatever means available. d. Phase referencing a. Packet 110. b. Frame 111. Pulse – amplitude modulation signals c. Datagram are multiplexed by using d. Data a. Subcarrier 125. b. Bandpass filters 126. Transmitting the data signal directly c. A/D converters over the medium is referred to as d. FET switches a. baseband 112. b. broadband 113. It is the ratio of the transmission bit c. ring rate to the minimum bandwidth required for d. bus a particular modulation scheme. 127. a. Bandwidth efficiency 128. The main reason that serial b. All of these transmission is preferred to parallel c. Information density transmission is that? d. Spectral efficiency a. serial is faster 114. b. serial requires only a single channel 115. Ethernet is baseband transmission c. serial requires multiple channels system designed by _____. d. parallel is too expensive a. Thomas Murray and Robert Metcalfe 129. b. David Boggs and Thomas Murray 130. Which of the following is not a c. Thomas Murray and Emile Baudot LAN? d. Robert Metcalfe and David Boggs a. PBX system 116. b. Hospital system 117. It is a system where the digital c. Office building system signals are placed directly on the coaxial d. Cable TV system cable. 131. a. Broadband 132. A modulation technique where data b. Baseband rates in excess of 56 kbps can be achieved c. CSMA/CD over telephone circuits d. Token ring a. ASK 118. b. Trellis Code Modulation 119. A basic group B c. GSK a. Occupies the frequency range d. Any of these from 60 to 108 kHz 133. b. Consists of erect channels only 134. It is how the primary designates the c. Is formed at the group translating secondary as the designation of recipient of equipment data. d. Consists of 5 supergroups a. Line turnaround 120. b. Selection c. Line control quantizing noise introduces d. Control Protocol c. its incompatibility with TDM 135. d. the large bandwidths that are 136. It is the process of compressing and required for it expanding and is a means of improving the 149. T1 stands for dynamic range of communications system. a. Transmission one a. Pre-emphasis b. Telecommunication one b. Filtering c. Telex one c. De-emphasis d. Transmission line one d. Companding 150. 137. 151. Involves compression in the 138. The supergroup pilot is transmitter after the input sample has been a. applied to each multiplexing bay converted to a linear PCM code and then b. used to regulate the gain of expansion in the receiver prior to PCM individual repeaters coding c. applied at each adjustable equalizer a. analog companding d. fed in at a GTE b. A – law companding 139. c. Digital companding 140. The time it takes to transmit one d. U – law companding TDM frame is called ______. 152. a. Slot time 153. Mark and space refer respectively to b. Frame time a. dot and dash c. Transmission time b. message and interval d. Any of these c. binary 1 and binary 0 141. d. on and off 142. It is the thermal noise power 154. normalized to 1-Hz bandwidth 155. Variation of biphase that is used for a. power density ratio encoding SMPTE time code data and for b. thermal noise recording on video tapes c. noise power density a. Biphase - M d. ambient temperature noise b. B8Z 143. c. Manchester 144. It is the procedure used to decide d. UPNRZ which device has the permission to transmit 156. at any given time 157. Pulse width modulation may be a. Flow control generated b. Sequence control a. by differentiating pulse position c. Line control modulation d. Framing b. with a monostable multivibrator 145. c. by integrating the signal 146. Any rounded – off errors in the d. with a free running multivibrator transmitted signal are reproduced when the 158. code is converted back to analog in the 159. The ISDN channel D designates receiver. _____ which contains control information. a. Aperture error a. Data b. Quantization error b. Flow c. Aperture distortion c. Control d. Slope overload d. Bearer 147. 160. 148. The biggest disadvantage of PCM is 161. A transmission of binary data which a. its inability to handle analog signals involves the transmission of two non – zero b. the high error rate which is voltage level a. Unipolar a. Shift register b. Polar b. XOR c. Bipolar c. 2 – to – 4 level converter d. Non – return to zero d. UART 162. 177. 163. 178. 164. Switching systems 179. An IC that contains A/D and D/A a. improve the efficiency of data converters, companders, and parallel-to- transfer serial converters is called a b. are not used in data systems a. Codec c. require additional lines b. Data converter d. are limited to small data networks c. Multiplexer 165. d. Modem 166. It involves converting standard logic 180. levels to a form more suitable to telephone 181. Data communications refers to the transmission lines transmission of a. Transmission line encoding a. voice b. Physical line encoding b. video c. Digital line encoding c. computer data d. Multiplexing d. all of the above 167. 182. 168. The primary advantage of digital 183. The number of amplitude, frequency, transmission or phase changes that take place per second a. economical is known as the b. reliability a. data rate in bits per second c. noise immunity b. frequency of operation d. efficiency c. speed limit 169. d. baud rate 170. Part of the PCM system that prevents 184. aliasing or foldover distortion 185. The basic modulator and a. Bandpass filter demodulator circuits in PSK are b. Anti – foldover distortion a. PLLs c. Anti – aliasing b. Balanced modulators d. Any of these c. Shift registers 171. d. Linear summers 172. It is defined as the process of 186. transforming messages or signals in 187. What is the result if the input of accordance with a definite set of rules. ADC is changing while performing a. Quantizing conversion? b. Sampling a. Aperture error c. Coding b. Overload distortion d. Decoding c. Aliasing 173. d. Aperture distortion 174. The PCM code for each channel 188. occupies a fixed time slot called 189. Information capacity is convenient to a. Frame time express as b. Baud a. baud c. Transmission time b. bits d. Epoch c. dot length 175. d. bits per second or bps 176. The building block of a parity or 190. BCC generator is ______. 191. Which medium is the least susceptible to noise? b. Modem a. twin lead c. Codec b. fiber – optic cable d. Muldem c. twisted pair 206. d. coax 207. What is the type of mastergroup used 192. for low – capacity microwave systems? 193. a. A600 194. The RS – 232 interface b. U600 a. interconnects data sets and the c. L600 transmission circuits d. L400 b. uses several different connectors 208. c. permits custom wiring of signal lines 209. An FDM hierarchy which is formed to the connector pins as desired by frequency – division multiplexing five d. all of the above groups containing 12 channels each for a 195. combined bandwidth of 240 kHz. 196. The ISDN channel B designates a. Supergroup ______. b. Group a. Bearer c. Mastergroup b. Data d. Jumbogroup c. Control 210. d. Flow 211. The result whenever the sampling 197. rate is less than twice the highest audio 198. Data transmission of the character at frequency a time with start and stop bits is known as a. peak limiting what type of transmission? b. overload distortion a. asynchronous c. alias b. serial d. quantizing noise c. synchronous 212. d. parallel 213. The most critical and difficult part 199. of receiving a direct – sequence spread 200. Sampling technique that when the spectrum signal is tops of the sample pulses retain their natural a. Frequency synthesis shape during the sample interval b. Synchronism a. unnatural sampling c. PSN code generation b. flat top sampling d. Carrier recovery c. natural sampling 214. d. free sampling 215. An FDM hierarchy which is formed 201. by frequency – division multiplexing 10 202. A modem converts super groups together for a combined a. Analog signals to digital capacity of 600 voice band message b. Digital signals to analog channels c. Digital signals to analog and vice- a. Supergroup versa b. Group d. None of these c. Mastergroup 203. d. Jumbogroup 204. 216. 205. It is a large scale integration chip 217. It is the transmittal of digital signals designed for use in telecommunication between to or more points in a industry for private branch exchanges, communication system. central office switches, digital handsets a. Digital transmittal and digital echo suppressors. b. Digital communications a. Vocoder c. Digital radio d. Data communications 230. 218. 231. A form of digital modulation similar 219. It is logically equivalent to making to PSK except the digital information is telephone call through the DDD network contained in both the amplitude and the except no direct end-to-end connection is phase of the transmitted carrier. made a. ASK a. Normal call b. FSK b. Completed call c. QAM c. Logical call d. PSK d. Virtual call 232. 220. 233. For the 16-PSK and a transmission 221. It is proposed network designed by system with a 10kHz bandwidth, major telephone companies in conjunction determine the maximum bit rate with the ITU-T with the intent of a. 40,000 bps providing worldwide telecommunications b. 80,000 bps support for voice, data, video and c. 20,000 bps facsimile information within the same d. 16,000 bps network 234. a. ISDN 235. It is an empirical record of a b. Broadband communications system’s actual bit error performance. c. ATM a. probability of error d. Ethernet b. error detection 222. c. error control 223. Full duplex operation d. bit error rate a. requires two pair of cables 236. b. can transfer data in both directions at 237. It is a function of the carrier-to-noise once power ratio and the number of possible c. requires modems at both ends of the encoding conditions used circuit a. probability of error d. all of these b. error detection 224. c. error control 225. The most widely used data d. bit error rate communications code is 238. a. Morse code 239. It is used to compare two or more b. ASCII digital modulation systems that use c. Baudot different transmission rates, modulation d. EBCDIC scheme or encoding techniques 226. a. Energy per b it-to-noise power 227. Ten bit error occurs in two million density ratio transmitted. The bit error rate is b. Noise power density a. 2 x 10^-5 c. Power density ratio b. 5 x 10^-5 d. Carrier-to-noise ratio c. 5 x 10^-6 240. d. 2 x 10^-6 241. Indicate which of the following is 228. not a binary code 229. It is a type of FSK where the mark a. Morse and space frequencies are synchronized b. Baudot with the input binary rate c. CCITT-2 a. QFSK d. ARQ b. GFSK 242. c. CPFSK 243. To permit the selection of 1 out of 16 d. GSK equiprobable events, the number of bits required is form quantizing distortion a. 2 d. in PCM receivers, to overcome b. log 16 base 10 impulse noise c. 8 256. d. 4 257. Transmitting data as serial binary 244. word is called ______. 245. The type of modulation most often a. digital communications used with direct-sequence spread spectrum b. quantizing is c. PAM a. QAM d. PCM b. SSB 258. c. FSK 259. Emphasizing low-level signals and d. PSK compressing higher level signals is called 246. a. quantizing 247. Indicate the false statement. In order b. companding to combat noise, c. pre-emphasis a. the channel bandwidth may be d. sampling increased 260. b. redundancy may be used 261. Which circuit is most common to c. the transmitted power may be both frequency-hopping and direct- increased sequence spread spectrum transmitters? d. the signaling rate may be reduced a. correlator 248. b. frequency synthesizer 249. Which of the following is not c. PSN code generator commonly used method of error detection? d. Sweep generator a. Parity 262. b. BCC 263. One of the most important aspect of c. CRC any communication system because it is d. redundancy costly and limited 250. a. bandwidth 251. Quantizing noise occurs in b. equipments a. time-division multiplex c. time b. frequency-division multiplex d. personnel c. pulse-code modulation 264. d. pulse-width modulation 265. It consist essentially of sampling 252. analog information signals and then 253. In order to reduce quantizing noise, converting those samples into discreet one must pulses of transporting the pulses from the a. increase the number of standard source to destination over a physical amplitudes transmission medium b. send pulses whose sides are more a. Pulse modulation nearly vertical b. Amplitude modulation c. use an RF amplifier at the receiver c. Frequency modulation d. increase the number of samples per d. Digital modulation second 266. 254. 267. He is credited with inventing PCM in 255. Companding is used 1937 a. to overcome quantizing noise in a. N. S. Kapany PCM b. A. H. Reeves b. in PCM transmitters, to allow c. E. H. Alpine amplitude limiting in the receiver d. A. C. S. Van Heel c. to protect small signals in PCM 268. 269. Data communications uses digital-to-analog converter in the receiver a. Analog methods a. Coding efficiency b. Digital methods b. Companding c. All of these c. Pre-emphasis d. None of these d. Dynamic range 270. 283. 271. An integrated circuit that performs 284. Devices used for digitizing speech the PCM encoding and decoding functions signals only a. Codec a. codec b. Modem b. muldem c. Muldem c. vocoders d. Digital-to-analog converter d. modem 272. A synchronous transmission usually 285. What is the minimum bandwidth begins with which character? required to transmit a 56 kbps binary a. SYN signal with no noise? b. STX a. 14 kHz c. SOH b. 56 kHz d. ETB c. 28 kHz 273. d. 112 kHz 274. A theory that establishes the 286. minimum sampling rate that can be used 287. Type of PCM that uses single-bit for a given PCM systems PCM code to achieve digital transmission a. Nyquist sampling theorem of analog signals b. Nyquist minimum bandwidth a. Adaptive delta modulation c. Nyquist minimum bandwidth b. Pulse code modulation d. Any of these c. Differential modulation 275. d. Delta modulation 276. Sixteen different levels (symbols) are 288. used to encode binary data. The channel 289. It is a delta modulation system where bandwidth is 36 MHz. The maximum the step size of the digital-to-analog channel capacity is converter is automatically varied, a. 18 Mbps depending on the analog input signal. b. 72 Mbps a. Adaptive Delta Modulation c. 288 Mbps b. PCM d. 2.176 Gbps c. Differential modulation 277. d. Delta modulation 278. Assigning PCM codes to absolute 290. magnitudes 291. A QAM modulator does not use a. Coding ____. b. Quantizing a. XNOR c. Sampling b. Bit Splitter d. Any of these c. Balanced modulator 279. d. 2-to-4 level converter 280. A popular PC protocol is 292. a. Parity 293. It is a form of phase-division b. Xmodem multiplexing where two data channels c. CRC modulate the same carrier frequency that d. LRC is shifted 90 degrees in phase. 281. a. PSK 282. It is the ratio of the largest possible b. FSK magnitude to the smallest possible c. QAM magnitude that can be decoded by the d. ASK 294. 299. A special device that upgrades 295. One eight-bit PCM code is called signals from one level to a higher level of ______. the hierarchy in multiplexing a. FDM frame a. Muldem b. TDM time slot b. Vocoder c. TDM frame c. Modem d. FDM time slot d. Codec 296. 300. 297. It is communications system that 301. A transmission of binary data which uses digital pulse rather than analog involves the transmission of only a single signals to encode information non-zero voltage level. a. Digital carrier system a. Unipolar b. Digital baseband system b. Bipolar c. Digital service system c. Polar d. Digital broadband system d. Non-return to zero 298. 302. 303. 304. MULTIPLE CHOICE 305. QUESTIONS

306. 307. IN

308. 309. ELECTRONICS SYSTEMS AND TECHNOLOGIES (EST)

310. 311. Antennas

312. 313. MELVIN C. ARCEO, ECE 314. PERC DC

315.

316. 317. ENCODED BY: 318. BADILLO, AIMIE E. 319. 2006105942 320. ECE003/C11 321. 329. 322. 330. 323. 331. 324. 332. 325. 333. 326. 334. 327. 335. 328. 336. 1. It is a metallic conductor system capable of 8. Electrical energy that has escaped into free radiating and capturing electromagnetic space in the form of transverse energy electromagnetic waves a. transmission lines a. Radio waves b. antenna b. Frequency c. waveguides c. Signal d. load d. Wavelength 337. 344. 2. A directional antenna with two or more 9. The length of the ground plane vertical at elements is known as 146 MHz is a. folded dipole a. 1.6 ft b. ground plane b. 1.68 ft c. loop c. 2.05 ft d. array d. 3.37 ft 338. 345. 3. The ratio of the focal length to the diameter 10. Using a small reflector to beam waves to the of the mouth of the parabola is called _____. larger parabolic reflector is known as a. aperture a. Focal feed b. focal point b. Horn feed c. foci c. Cassegrain feed d. major axis d. Coax feed 339. 346. 4. The impedance of a dipole is about 11. The plane parallel to the mutually a. 50-ohm perpendicular line in the electric and b. 73-ohm magnetic fields is called ______. c. 93-ohm a. wavefront d. 300-ohm b. point source 340. c. isotropic source 5. A special type of transmission line that d. rays consist of conducting metallic tube through 347. which high frequency electromagnetic 12. What is the beamwidth of a parabolic energy is propagated antenna with a diameter of 5 meters and an a. medium operating frequency of 10 GHz? b. microstrip a. 0.5 degrees c. stripline b. 0.675 degrees d. waveguide c. 0.348 degrees 341. d. 3.48 degrees 6. Calculate the angle of declination for an 348. antenna using a polar mount at a latitude of 13. The horizontal radiation pattern of a dipole 45 degrees is a a. 3.2 degrees a. circle b. 1.3 degrees b. figure of eight c. 4.2 degrees c. clover leaf d. 6.81 degrees d. narrow beam 342. 349. 7. The cone angle of the flare angle of a 14. The size of antenna is inversely proportional conical horn antenna is approximately to ______. a. 55 degrees a. frequency b. 45 degrees b. power c. 40 degrees c. radiation resistance d. 50 degrees d. wavelength 343. 350. 15. A popular half – wave antenna is the 22. Calculate the characteristic impedance of a a. Ground plane quarter – wavelength section used to connect b. End-fire a 300-ohm antenna to a 75-ohm line c. Collinear a. 150 ohms d. Dipole b. 120 ohms 351. c. 130 ohms 16. Calculate the gain of a parabolic antenna d. 110 ohms using a 2.5-m radius dish operating at 357. 10GHz. 23. Plots of field strength or power density with a. 166.673 dB respect to the value at a reference point b. 83.7 dB a. absolute front lobe pattern c. 52.2 dB b. relative front lobe pattern d. 45.6 dB c. relative front lobe pattern 352. d. relative radiation pattern 17. It is the ratio of the radiated to the reflected 358. energy 24. What must be the height of a vertical a. Radiation resistance radiator one half wavelength high if the b. Radiation efficiency operating frequency is 1100 kHz? c. Radiation constant a. 120 m d. Radiation antenna b. 136 m 353. c. 115 m 18. The feed mechanism in a parabolic antenna d. 124 m that radiates the electromagnetic energy. 359. a. Primary antenna 25. Lobes adjacent to the front lobe b. Reflectors a. Diagonal lobes c. Secondary antenna b. Side lobes d. Focal point c. Front lobes 354. d. Back lobes 19. It is a polar diagram or graph representing 360. field strengths or power densities at various 26. Lobes in a direction exactly opposite of the angular positions relative to an antenna front lobe a. Side lobe a. Side lobes b. Front lobe b. Adjacent lobes c. Radiation pattern c. Front lobes d. Radiation constant d. Back lobes 355. 361. 20. For a transmit antenna with a radiation 27. Calculate the efficiency of an antenna that resistance of 72 ohms, an effective antenna has a radiation resistance of 73 ohms and an resistance of 8 ohms, a directive gain of 20 effective dissipation resistance of 5 ohms and an input power of 100W, determine the a. 98.3% antenna gain. b. 93.6% a. 12.55 dB c. 90.7% b. 10.43 dB d. 95.5% c. 11.21 dB 362. d. 9.78 dB 28. The line bisecting the major lobe, or 356. pointing from the center of the antenna in 21. The radiation pattern plotted in terms of the direction of maximum radiation is called electric field strength or power density ______. a. absolute radiation pattern a. line of shoot b. relative radiation pattern b. diagonal shoot c. absolute front lobe pattern c. bisecting shoot d. absolute side lobe pattern d. antenna shoot 29. The ammeter connected at the base of a 35. It is the ratio of the power radiated by the Marconi antenna has a certain reading. If antenna to the total input power. this reading is increased 2.77 times, what is a. antenna efficiency the increase in output power? b. reflection coefficient a. 3.45 c. standing wave ratio b. 1.89 d. radiation resistance c. 2.35 370. d. 7.67 36. If a 500 kHz transmitter of a constant power 363. produces field strength of 100uV/m at a 30. Refers to a field pattern that is close to the distance of 100 mi from the transmitter, antenna. what would be the theoretical field strength a. Induction field at a distance of 200 mi from the transmitter? b. Far field a. 45 uV/m c. Radiation field b. 100 uV/m d. Capture field c. 50 uV/m 364. d. 35 uV/m 31. A half-wave dipole is driven with a 5-W 371. signal at 225 MHz. A receiving dipole 100 37. An antenna that transmits or receives km. Calculate the received power into a 73- equally well in all directions is said to be ohm receiver. _____. a. 23.5 pW a. omnidirectional b. 7.57 pW b. bidirectional c. 5.64 pW c. unidirectional d. 1.26 pW d. quasidirectional 365. 372. 32. It is the resistance that, if it replaced the 38. It is the ratio of the power density radiated antenna, would dissipate exactly the same in a particular direction to the power density amount of power that the antenna radiates. radiated to the same point by a reference a. Directive gain antenna, assuming both antennas are b. Antenna efficiency radiating the same amount of power c. Radiation resistance a. power gain d. Antenna resistance b. directive gain 366. c. total gain 33. What is the effective radiated power of a d. system gain television broadcast station if the output of 373. the transmitter is 1000W, antenna 39. If the field intensity of 25 mV/m develops transmission line loss is 50W, and the 2.7 V in a certain antenna, what is its antenna power gain is 3? effective height? a. 1250 W a. 110 m b. 2370 W b. 100 m c. 2130 W c. 98 m d. 2850 W d. 108 m 367. 374. 34. It is the ratio of the power radiated by an 40. The magnetic field of an antenna is antenna to the sum of the power radiated and perpendicular to the earth. The antenna’s the power dissipated. polarization ______. a. radiation resistance a. is vertical b. coupling coefficient b. is horizontal c. antenna efficiency c. is circular d. antenna beamwidth d. cannot be determined from the 368. information given 369. 375. 41. If the power of a 500 kHz transmitter is b. 40 dBW increased from 150 W to 300 W, what would c. 50 dBW be the percentage change in field intensity at d. 20 dBW a given distance from the transmitter? 381. a. 141% 47. If energy is applied at the geometrical center b. 150% of antenna, the antenna is said to be _____. c. 100% a. center-fed d. 133% b. end-fed 376. c. quarterwave-fed 42. It is the same with directive gain except that d. halfwave-fed the total power fed to the antenna is used 382. and the antenna efficiency is taken into 48. For a transmit antenna with a power gain of account. 10 and an input power of 100W, determine a. system gain the power density at a point 10 km from the b. power gain transmit antenna c. directive gain a. 0.574 uW/m^2 d. total gain b. 0.796 uW/m^2 377. c. 1.24 uW/m^2 43. A hip-radio telephone transmitter operates d. 0.981 uW/m^2 on 2738 kHz. At a certain point distant from 383. the transmitter, the 2738 kHz signal is 49. For a transmit antenna with a radiation measured field of 147 mV/m. The second resistance of 72 ohms, an effective antenna harmonic field at the same point is measured resistance of 8 ohms, a directive gain of 20 as 405 uV/m. To the nearest whole unit in and an input power of 100W, determine the decibels, how much has the harmonic antenna efficiency. emission been attenuated below the 2738 a. 90% kHz fundamental? b. 96% a. 43.2 dB c. 98% b. 51.2 dB d. 96% c. 35.1 dB 384. d. 25.1 dB 50. The fields surrounding the antenna do not 378. collapse their energy back into the antenna 44. It is the equivalent power that an isotropic but rather radiate it out in space. antenna would have to radiate to achieve the a. induction field same power density in the chosen direction b. near field at a given point as another antenna. c. radiation field a. EIRP d. magnetic field b. ERP 385. c. IRL 51. For receive power density of 10 uW/m^2 d. RSL and a receive antenna with a capture area of 379. 0.2 m^2, determine the captured power. 45. When the energy is applied to the antenna at a. 0.5 uW a point of high – circulating current. b. 2 uW a. voltage-fed antenna c. 1 uW b. power-fed antenna d. 1.5 uW c. current-fed antenna 386. d. impedance-fed antenna 52. The property of interchangeability for the 380. transmitting and receiving operations is 46. For a transmit antenna with a power gain of known as ______. 10 and an input power of 100W, determine a. efficiency the EIRP in watts. b. accuracy a. 30 dBW c. reciprocity d. polarization transmission line is connected is called 387. ______. 53. The length of a doublet at 27 MHz is _____. a. center feed a. 8.67 ft b. end feed b. 17.3 ft c. feedpoint c. 18.2 ft d. voltage feed d. 34.67 ft 395. 388. 61. A popular vertical antenna is the _____> 54. Refers to the orientation of the electric field a. collinear radiated from an antenna. b. dipole a. efficiency c. ground plane b. beamwidth d. broadside c. polarization 396. d. accuracy 62. The discone antenna is 389. a. a useful direction-finding antenna 55. At frequencies below 2 MHz, what type of b. used as a radar receiving antenna antenna is usually used? c. circularly polarized with other a. Marconi antenna circular antennas b. Hertzian antenna d. useful as a UHF receiving antenna c. Hertz antenna 397. d. Elementary doublet 63. The feedpoint presents and ac load to the 390. transmission line called 56. The angular separation between two half- a. antenna output impedance power points in the major lobe of the b. antenna input impedance antenna’s plane radiation pattern. c. feedpoint impedance a. bandwidth d. center feed impedance b. polarization 398. c. efficiency 64. A helical antenna is used for satellite d. beamwidth tracking because of its 391. a. circular polarization 57. Hertz antenna are predominantly used with b. maneuverability frequencies above c. broad bandwidth a. 3 MHz d. good front to back ratio b. 4 MHz 399. c. 5MHz 65. The simplest type of antenna. d. 2MHz a. Elementary doublet 392. b. Half-wave dipole 58. Defined as the frequency range over which c. Quarterwave dipole antenna operation is satisfactory d. 5/8 wavelength dipole a. beamwidth 400. b. channel 66. Zoning is used with a dielectric antenna in c. bandwidth order to d. baseband a. reduce the bulk of the lens 393. b. increase the bandwidth of the lens 59. One of the following is not an c. permit pin-point focusing omnidirectional antenna. d. correct the curvature of the a. Half-wave dipole wavefront from a horn that is too b. Log-periodic short c. Discone 401. d. Marconi 402. 394. 403. 60. The point on the antenna where the 67. It is an electrically short dipole a. short dipole a. helical b. quarterwave dipole b. small circular loop c. half-wave dipole c. parabolic reflector d. yagi antenna d. Yagi – Uda 404. 412. 68. Cassegrain feed is used with parabolic 75. It is a wire structure placed below the reflector to antenna and erected above the ground. a. increase the gain of the system a. ground plane b. increase the bandwidth of the system b. counterpoise c. reduce the size of the main reflector c. ground lines d. allow the feed to be placed at a d. top hat convenient point 413. 405. 76. Which of the following terms does not apply 69. The half-wave dipole is generally referred to to the Yagi-Uda array? as ______. a. good bandwidth a. Yagi antenna b. parasitic elements b. Hertzian antenna c. folded dipole c. Marconi antenna d. high gain d. Hertz antenna 414. 406. 77. It effectively cancels out the capacitance 70. Top loading is sometimes used with an component of the antenna input impedance. antenna in order to increase its a. ground plane a. effective height b. top hat b. bandwidth c. loading coil c. beamwidth d. shunt capacitance d. input capacitance 415. 407. 78. Indicate which of the following reasons for 71. What is the directivity of a Hertz antenna? the use of an earth mat with antenna is false: a. 1.64 a. impossibility of a good ground b. 2.18 conduction c. 2.15 b. provision of an earth for an antenna d. 1.75 c. protection of personnel working 408. underneath 72. The standard reference antenna for the d. improvement of the radiation pattern directive gain is the ______. of the antenna a. infinitesimal dipole 416. b. isotropic antenna 79. A metallic array that resembles a spoke c. elementary doublet wheel placed at the top of an antenna, it d. half-wave dipole increases the shunt capacitance to ground 409. reducing the overall antenna capacitance. 73. An antenna which is one-quarter wavelength a. loading coil long, mounted vertically with the lower end b. top loading either connected directly to ground or c. series capacitance grounded through the antenna coupling d. series inductors network. 417. a. loop antenna 80. Indicate the antenna that is not wideband: b. hertzian dipole a. discone c. monopole antenna b. folded dipole d. turnstile antenna c. helical 410. d. marconi 411. 418. 74. An antenna that is circularly polarized is the 81. It is formed when two or more antenna elements are combined to form a single d. parasitic element antenna. 425. a. antenna elements 88. One of the following is very useful as a b. antenna array multi-band HF receiving antenna. This is c. driven elements the: d. parasitic elements a. conical horn 419. b. folded dipole 82. One of the following is not a reason for the c. log-periodic use of an antenna coupler: d. square loop a. to make the antenna look resistive 426. b. to provide the output amplifier with 89. A parasitic element that is longer than the the correct load impedance driven element from which it receives c. to discriminate against harmonics energy. d. to prevent reradiation of local a. driven element oscillators b. director 420. c. parasitic elements 83. It is an individual radiator, such as a half or d. reflector quarter-wave dipole. 427. a. antenna element 90. One of the following consists of non- b. antenna array resonant antennas. c. reflector a. rhombic antenna d. director b. folded-dipole antenna 421. c. end-fire antenna 84. Indicate which of the following reasons for d. broadside antenna using a counterpoise with antennas is false: 428. a. impossibility of a good ground 91. A parasitic element that is shorter than its connection associated driven element. b. protection of personnel working a. redirector underneath b. director c. provision of an earth for the antenna c. reflector d. rockiness of the ground itself d. parasitic element 422. 429. 85. Type of antenna element that is directly 92. An ungrounded antenna near the ground. connected to the transmission lines and a. acts as a single antenna near the receives from or is driven by the source. ground a. driven array b. is unlikely to need an earth mat b. parasitic array c. acts as an antenna array c. driven element d. must be horizontally polarized d. parasitic element 430. 423. 93. It is a non-resonant antenna capable of 86. Which of the following antennas is best operating satisfactorily over a relatively excited from a waveguide? wide bandwidth, making it ideally suited for a. biconical HF transmission. b. horn a. turnstile antenna c. helical b. loop antenna d. discone c. rhombic antenna 424. d. discone antenna 87. Type of antenna element that is not 431. connected to the transmission lines. 94. A wide – bandwidth multi-element driven a. parasitic array array is the ______. b. driven array a. end-fire c. parasitic array b. log-periodic c. yagi d. 28 degrees d. collinear 438. 432. 102. It is the ratio of the highest to the 95. It is a linear array antenna consisting of a lowest frequency over which an antenna dipole and two or more parasitic elements: will satisfactorily operate. one reflector and one director. a. channel ratio a. broadside antenna b. bandwidth ratio b. end-fire antenna c. reflection ratio c. yagi-uda antenna d. dynamic range d. phased array antenna 439. 433. 103. An antenna has a power gain off 15. 96. An antenna which is consists of a cone that The power applied to the antenna is 32 W. is truncated in a piece of circular waveguide. The effective radiated power is ______. a. pyramidal horn antenna a. 15 W b. circular horn antenna b. 32 W c. rectangular horn antenna c. 120 W d. circular horn antenna d. 480 W 434. 440. 97. Which antenna has a unidirectional radiation 104. It is simply a single-turn coil of wire pattern and gain? that is significantly shorter than one a. dipole wavelength and carries RF current. b. ground plane a. turnstile antenna c. yagi b. loop antenna d. collinear c. rhombic antenna 435. d. long-wire antenna 98. An antenna formed by placing two dipoles 441. at right angles to each other, 90 degrees out 105. A coax has an attenuation of 2.4 dB of phase. per 100 ft. The attenuation of 275 ft a. discone antenna a. 2.4 dB b. turnstile antenna b. 3.3 dB c. bicone antenna c. 4.8 dB d. 5/8 wavelength antenna d. 6.6 dB 436. 442. 99. The radiation pattern of collinear and a 106. It is group of antenna arrays that broadside antenna is ______. when connected together, function as a a. omnidirectional simple antenna whose beamwidth and b. bidirectional direction can be changed electronically c. unidirectional without having to physically move any of d. clover-leaf shaped the individual antennas or antenna elements within the array. 100. What is the bandwidth ration of log- a. end-fire array periodic antenna? b. broadside antenna a. 10:1 c. phased array antenna b. 5:1 d. log-periodic antenna c. 20:1 443. d. 1:10 107. Conductors in multi-element 437. antennas that do not receive energy 101. Which beam width represents the directly from the transmission line are best antenna directivity? known as ______. a. 7 degrees a. parasitic element b. 12 degrees b. driven element c. 19 degrees c. the boom d. receptor 114. An antenna that provides extremely 444. high gain and directivity and very popular 108. It is a broadband VHF or UHF for microwave radio and satellite antenna that is suited for applications for communications link. which radiating circular rather than a. helical antenna horizontal or vertical polarized b. parabolic antenna electromagnetic waves are required. c. hyperbolic antenna a. discone antenna d. log-periodic antenna b. bicone antenna 450. c. log-periodic antenna 115. Part of a parabolic antenna that d. helical antenna houses the primary antenna which radiates 445. electromagnetic waves toward the 109. Mode of propagation of helical reflector. antenna where electromagnetic radiation is a. feed mechanism in the direction at right angles to the axis b. focal point of the helix. c. center feed a. normal mode d. feed antenna b. axial mode 451. c. helix mode 116. It is a passive device that simply d. helical mode reflects the energy radiated by the feed 446. mechanism into a concentrated, highly 110. Mode of propagation of helical directional emission in which the antenna where the radiation of the antenna individual waves are all in phase with each in the axial direction and produces a other. broadband relatively directional pattern. a. director a. helical mode b. parabolic segment b. normal mode c. reflector c. axial mode d. feed mechanism d. helix mode 452. 447. 117. The energy near the edge of the 111. In a Yagi antenna, maximum parabolic dish that does not reflect but direction of radiation is toward the rather is diffracted around the edge of the a. director dish. b. driven element a. spillover c. reflector b. corona d. sky c. dissipated power 448. d. copper loss 112. It is defined as the ratio of the 453. antennas maximum gain in the forward 118. Determines the angular aperture of direction to its maximum gain in its the reflector, which indirectly determines backward direction how much the primary radiation is a. side-to-back ratio reflected by the parabolic dish. b. front-to-side ratio a. numerical aperture c. back-to-side ratio b. V number d. front-to-back ratio c. aperture number 449. d. aperture angle 113. The horizontal radiation pattern of a 454. vertical dipole is a ______. 119. For a 2-m diameter parabolic a. figure of eight reflector with 10W of power radiated by b. circle the feed mechanism operating at 6 GHz c. narrow beam with a transmit antenna efficiency of 55% d. clover leaf and an aperture efficiency of 55%, determine the beamwidth. c. voltage to any point of the antenna a. 1.25 degrees d. square of voltage to the square of b. 2.25 degrees current at any point in the antenna c. 1.5 degrees 461. d. 1.75 degrees 126. Consists of basic antenna connected 455. to a transmission line plus one or more 120. Type of feed mechanism where the additional conductors primary radiating source is located just a. parasitic array behind a small opening at the vertex of the b. directors paraboloid rather than at the focus. c. driven array a. cassegrain feed d. reflectors b. center feed 462. c. horn feed 127. Which of the following is not a d. driven array? 456. a. yagi 121. Discone radiation pattern is b. broadside a. omnidirectional c. collinear b. unidirectional d. end fire c. figure-of-eight 463. d. bidirectional 128. What is used to determine phase 457. difference between two broadcast 122. Which is properly terminated antennas? antenna? a. a phase monitor a. dipole b. a frequency monitor b. marconi c. an amplitude monitor c. hertz d. a power monitor d. rhombic 464. 458. 129. In antennas, which gives more 123. An example of a marconi antenna is forward gain? ______. a. reflector a. quarter wave vertical tower b. driven element b. collinear c. parasitic element c. yagi d. director d. rhombic 465. 459. 130. Which of the following is longer? 124. At the ends of a half-wave antenna, a. director what values of current and voltage exist b. reflector compared to the remainder of the antenna? c. driven element a. minimum voltage and maximum d. parasitic element current 466. b. minimum voltage and minimum 131. Which is closer to the driven current element? c. equal voltage and current a. parasitic element d. maximum voltage and minimum b. driven element current c. director 460. d. reflector 125. Radiation resistance is the ratio of 467. ______. 132. How much do they differ in length a. radiated power to the antenna center from a half-wavelength? current a. 5% b. radiated power to the square of the b. 10% antenna center current c. 15% d. 20% c. less acreage needed 468. d. it is unidirectional 133. How much more feed-point 475. impedance does a folded dipole have than 140. Why is the usual rhombic not a normal dipole? frequency – sensitive? a. two times as much a. unidirectional b. three times as much b. with its characteristic impedance c. four times as much c. less acreage required d. five times as much d. main lobe is greater than back lobe 469. 476. 134. How is it possible to produce 70- 141. In what direction is the null of small ohm twin lead? diameter loop in relation to the plane of a. by folding more parasitic element the loop? b. by manufacturing a. 45 degrees angle c. by increasing the radiation resistance b. 180 degrees angle d. by increasing the length of the c. 360 degrees angle antenna d. 90 degrees angle 470. 477. 135. With similar size parabolic, plane 142. When is a loop unidirectional? reflector, and corner-reflector beams, a. when horizontal which has greater gain? b. when vertical a. plane reflector c. when circular b. parabolic d. when unidirectional c. corner-reflector beam 478. d. V-beam 143. Why are verticals sometimes top- 471. loaded? 136. With similar size, which has the a. to resonate on high frequency narrowest lobes? b. to decrease the electrical length a. parabolic c. to resonate on low frequency b. V-beam d. to look better c. corner-reflector beam 479. d. plane reflector 144. Why is pi-network superior to direct 472. coupling to an antenna? 137. Why would the wires of V-beam be a. reduce harmonic radiation closer together when used on higher b. better frequency response frequencies? c. better radiation of energy a. main lobe lays farther to wire d. reduce power dissipation b. main lobe lays closer to wire 480. c. secondary lobes closer to wire 145. Why might L networks be used d. secondary lobes farther to wire between an antenna and transmission line? 473. a. step impedance up 138. How the V-beam is made b. step impedance down unidirectional? c. better radiation of energy a. impedance terminated d. reduce power radiation b. capacitive terminated 481. c. inductive terminated 146. Why are antenna ammeters often d. resistor terminated shorted out or disconnected from the 474. antenna except when readings are desired? 139. Why might a rhombic be better than a. to replace it with dummy a V-beam? b. not to interface with transmission a. it is resistor terminated c. for proper reception of signals b. more acreage needed d. to protect from lightning 482. 509. 147. Device to split transmission line 510. current to two or more antenna towers 511. a. splitter 512. b. coupler 513. c. isolator 514. d. phasor circuit 515. 483. 516. 148. What method can be used to 517. determine the feed-point impedance of a 518. vertical antenna? 519. a. resistance substitution 520. b. 521. c. dissipated resistance measurement 522. d. grounding the antenna 523. 484. 524. 149. In what unit is field intensity 525. measured? 526. a. volts 527. b. amperes 528. c. watts/m 529. d. mV/m 530. 485. 531. 150. How fast does low-frequency field 532. strength attenuate? 533. a. directly proportional to distance 534. b. inversely proportional to distance 535. c. directly proportional to time 536. d. inversely proportional to time 537. 486. 538. 487. 539. 488. 540. 489. 541. 490. 542. 491. 543. 492. 544. 493. 545. 494. 546. 495. 547. 496. 548. 497. 549. 498. 550. 499. 551. 500. 552. 501. 553. 502. 554. 503. 555. 504. 556. 505. 557. 506. 558. 507. 559. 508. 560. 561. 565. 562. 566. 563. 567. 564. 568. MULTIPLE CHOICE 569. QUESTIONS

570. 571. IN

572. 573. ELECTRONICS SYSTEMS AND TECHNOLOGIES (EST)

574. 575. Broadcast Engineering

576. 577. MELVIN C. ARCEO, ECE 578. PERC DC

579.

580. 581. ENCODED BY: 582. BADILLO, AIMIE E. 583. 2006105942 584. ECE003/C11 585. 586. 587. 588. 589. 590. 591. 592. 593. 594. 595. 1. In stereophonic broadcast, the center frequency of each SCA Subcarrier shall be kept at all times within ______Hz of the authorized frequency. a. 200 b. 300 c. 400 d. 500 596. 2. Sawtooth generator circuits produce the scanning raster but the sync pulses are needed for a. linearity b. timing c. keystoning d. line pairing 597. 3. Which of the following camera tubes has minimum lag? a. Vidicon b. Plumbicon c. Saticon d. Iconoscope 598. 4. The service are in standard AM broadcast is described as ______if there is no fading of signal. a. Class A b. Secondary c. Class B d. Primary 599. 5. The vertical field-scanning frequency is ______Hz. a. 30 b. 60 c. 525 d. 15,750 600. 6. A 4.5-MHz signal which is equal to the difference between the picture and sound RF carrier frequencies in a 6-MHz TV channel. a. Audio frequency b. Video frequency c. Intercarrier frequency d. Subcarrier frequency 601. 7. A system where the modulated RF picture and sound carrier signals are distributed in a cable network, instead of wireless system. a. CCTV b. MATV c. CATV d. SATV 602. 8. A class A FM station is limited in antenna height of ______feet above average terrain. a. 1000 b. 2000 c. 4000 d. 5000 603. 9. What circuit in the TV receiver is used to develop the high voltage needed to operate the picture tube? a. Low-voltage power supply b. Horizontal output c. Vertical sweep d. Sync separator 604. 10. The modulated picture carrier wave includes the composite video signal as the a. Average carrier level b. Symmetric envelope of amplitude variations c. Lower sideband without the upper sideband d. Upper envelope without the lower envelope 605. 11. With which emission type is the capture-effect more pronounced? a. CW b. FM c. SSB d. AM 606. 12. The hue of color sync phase is a. red b. cyan c. blue d. yellow green 607. 13. How much is the equivalent internal resistance of the electron beam with a 1.2-mA beam current at 25 kV? a. 48 nano ohms b. 30 ohms c. 20.8 mega ohms d. 15.6 kilo ohms 608. 14. The difference between the picture and sound carrier frequencies for channel 3 is ______MHz. a. 3.58 b. 64.5 c. 4.5 d. 6.75 609. 15. Refers to the deviation of the operating frequency of a crystal oscillator from its nominal value due to temperature variations. a. drift b. flashover c. frequency deviation d. deviation ratio 610. 16. It is the measure of how many picture elements can be reproduced a. definition b. resolution c. detail d. any of these 611. 17. A 3.58-MHz subcarrier signal for color in television a. Hue signal b. Video signal c. Audio signal d. Chroma signal 612. 18. A class D FM station shall have an authorized power not exceeding ______watts. a. 20 b. 15 c. 10 d. 5 613. 19. Which of the following is not a benefit of cable TV? a. Lower-cost reception b. Greater stability c. Less noise, stronger signal d. Premium cable channels 614. 20. The width of the vertical sync pulse in the Philippine TV system is a. 21H b. 3H c. H d. 0.5H 615. 21. Term in communication which is referred, “to send out in all direction” a. announce b. broadcast c. transmit d. media 616. 22. The number of frames per second in the Philippine TV system is a. 60 b. 262 ½ c. 4.5 d. 30 617. 23. It means multiple outlines of edges to the right in the picture. a. ghosting b. ringing c. fading d. snowing 618. 24. In the Sawtooth waveform for linear scanning, a. the linear rise is for flyback b. the complete cycle includes trace and retrace c. the sharp reversal in amplitude produces trace d. the beam moves faster during trace and retrace 619. 25. The purpose of pre-emphasis and de-emphasis in FM broadcasting is to: a. increase the high frequency amplitude b. improve the audio harmonic c. decrease the low frequency amplitude d. improve the S/N ratio 620. 26. The part of the visible spectrum where camera pickup tubes have the greatest output is a. red b. blue c. yellow-green d. infrared 621. 27. The type of modulation of the sound carrier signal is ______. a. Pulse motion b. Phase modulation c. Amplitude modulation d. Frequency modulation 622. 28. A video or audio signal that can be used directly to reproduce the picture and sound. a. Baseband signal b. Broadband signal c. Electromagnetic wave signal d. Modulated signal 623. 29. Class B FM station should have an ERP not exceeding ______kW. a. 50 b. 40 c. 30 d. 20 624. 30. What technique is used to permit hundreds of TV signals to share a common cable? a. Frequency modulation b. Mixing c. Frequency division multiplexing d. Time division multiplexing 625. 31. Another name for the horizontal retrace in a TV receiver is the a. ringing b. burst c. damper d. flyback 626. 32. In the Philippine color television system, the intercarrier frequency, in MHz, is a. 3.58 b. 3.579645 c. 4.5 d. 45.75 627. 33. In channel 14 (470 to 476 MHz), the 3.58-MHz color signal is transmitted at a. 471.25 MHz b. 473.25 MHz c. 474.83 MHz d. 475.25 MHz 628. 34. Interlaced scanning eliminates a. snowing b. flicker c. distortion d. fading 629. 35. Beam alignment magnets for the camera tube are adjusted while rocking which color? a. Optical focus b. Electrical focus c. Beam current d. Shading 630. 36. What is a frequency discriminator? a. An FM generator b. A circuit for detecting FM c. A circuit for filtering two closely adjacent signals d. An automatic bandwidth circuit 631. 37. A system used in television field operation to make on-the-spot video tape recordings using portable TV cameras and VTRs. a. SNG b. ENG c. HAFC d. MATV 632. 38. Class B FM station shall have an authorized transmitter power not exceeding ______kW. a. 10 b. 100 c. 1000 d. 10000 633. 39. The total bandwidth of an NTSC TV signal is a. 3.58 MHz b. 4.5 MHz c. 6 MHz d. 10.7 MHz 634. 40. Referred to the oscillator signal “leak through” from a property neutralized amplifier such as a master oscillator power amplifier. a. carrier b. stray signal c. back wave d. loss wave 635. 41. Interlacing is used in television to a. produce the illusion of motion b. ensure that all lines on the screen are scanned, not merely the alternate ones c. simply the vertical sync pulse train d. avoid flicker 636. 42. Coaxial cable for distribution system has an impedance of a. 50 ohms b. 75 ohms c. 150 ohms d. 300 ohms 637. 43. The average voltage value of the 3.58-MHz modulated chrominance signal is a. zero for most colors b. close to black for yellow c. the brightness of the color d. the saturation of the color 638. 44. When does broadcast station conduct an equipment test? a. during day time b. during night time c. during experimental period d. at any time 639. 45. It causes the picture information to spread out or crowded at one end of the rater compared to the opposite end. a. Linear scanning b. Interlaced scanning c. Non-linear scanning d. Retrace 640. 46. If the camera cannot be placed far away enough to include everything in the scene, change the lens to one with a a. lower f rating b. higher f rating c. longer focal length d. shorter focal length 641. 47. Type of radio communication transmission utilizing frequency modulation technique a. television video b. broadcasting in 535-1606 kHz c. single sideband HF transmission d. television audio 642. 48. The amount of color in the picture or color intensity in the ______. a. color level b. chroma level c. saturation d. any of these 643. 49. One of the early radio transmitters which produced keyed carrier generating purer waveform than spark transmitter, used for high powered RF transmission and are limited to radio frequency of about 500 kHz. a. Arc transmitter b. Hartley transmitter c. Spark transmitter d. Frequency transmitter 644. 50. A technique where segments of videotape are joined by electronic erasing and recording to create a single program. a. masking b. segmenting c. editing d. programming 645. 51. A class C FM station has an authorized power not exceeding ______watts of ERP. a. 500 b. 750 c. 1000 d. 2000 646. 52. The assembly around the neck of a picture tube that produces the magnetic fields that deflect and scan the electron beams is called the ______. a. shadow mask b. phosphor c. electron gun d. yoke 647. 53. An odd number of lines per frame form part of every one of the world’s TV systems. This is ______. a. done to assist interface b. purely an accident c. to ensure that line and frame frequencies can be obtained from the same original source d. done to minimize interference with the chroma subcarrier 648. 54. The difference between the sound carrier and the color signal is a. 4.5 MHz b. 1.25 MHz c. 0.92 MHz d. 0.25 MHz 649. 55. In color television, it is made for uniform color in the raster. a. beam-landing adjustment b. degaussing c. internal blanking adjustment d. background control 650. 56. Which of the following camera tubes uses lead oxide for the photoconductive target plate? a. vidicon b. plumbicon c. saticon d. image orthicon 651. 57. The number of fields is ______per frame. a. 2 b. 60 c. 525 d. 262.5 652. 58. An RF carrier wave that is frequency – modulated by the baseband audio signal in TV broadcasting. a. Audio signal b. Video signal c. Intercarrier signal d. Color signal 653. 59. A class B FM station is limited in antenna height of ____ feet. a. 1000 b. 500 c. 250 d. 100 654. 60. The HV anode supply for the picture tube of a TV receiver is generated in the a. mains transformer b. vertical output stage c. horizontal output stage d. horizontal deflection oscillator 655. 61. A tap for the subscriber drop line has a a. high insertion loss b. high tap loss c. low tap loss d. 300-ohm impedance 656. 62. Which system can be used for both recording and playback? a. CED b. VHD c. laser disk d. VHS 63. The hue 180 degrees out of phase with red is ______. a. cyan b. yellow c. green d. blue 657. 64. It is used around the phosphor dots to make a darker black which improves contrast in the picture. a. black masking b. convergence adjustment c. shadow masking d. color parity adjustment 658. 65. A lens with lower f rating is _____ lens that allows more light input. a. slower b. wider c. narrower d. faster 659. 66. Picture frames are repeated at the rate of ___ per second. a. 30 b. 60 c. 45 d. 50 660. 67. The effective radiated power of a class A FM station should not exceed ______kW. a. 125 b. 30 c. 10 d. 1 661. 68. In television, 4:3 represents the a. interface ratio b. maximum horizontal deflection c. aspect ratio d. ration of the two diagonals 662. 69. Titling the viseo head gaps is necessary with the a. color under b. zero guard bands c. FM luminance signal d. Long – play tapes 663. 70. It is a special camera tube with a test pattern printed in the image plate. a. vidicon b. monoscope c. oscilloscope d. iconoscope 664. 71. The number of lines scanned per frame in the raster on the picture tube screen is a. 525 b. 262 ½ c. 20 d. 10 665. 72. One of the following is a high powered RF ac basic transmitter that has two or more stages, the oscillator stage which determines the frequency of operation and RF amplifier stage or stages that develop the high power output. The purpose of which is to develop a good frequency stability. a. MOPA b. Hartley c. Alexanderson d. Goldsmith 666. 73. Camera signal output without sync is called ______. a. black burst b. generator lock video c. composite video d. non-composite video 667. 74. The tint of the color is its _____. a. brightness b. contrast c. chroma d. hue 668. 75. Which frequency band is the standard AM radio broadcast? a. HF b. UHF c. MF d. VHF 669. 76. The I and Q composite color signals are multiplexed onto the picture carrier by modulating a 3.58 MHz subcarrier using a. FM b. PM c. DSB AM d. Vestigial sideband AM 670. 671. 77. The shadow mask in color picture tube is used to a. Reduce X-ray emission b. Ensure that each beam hits only its dots c. Increase screen brightness d. Provide degaussing for the screen 672. 78. The video heads rotate at high velocity to increase the a. tape speed b. writing speed c. reel rotation d. tape tension 673. 79. How do you eliminate radio frequency variation of an oscillator transmitter caused by its supply voltage? a. use of a regulated power supply b. use of a new power supply c. use of high capacitor in the supply circuit d. loosen power supply shielding 674. 80. The composite video signal includes the camera signal with the following except a. picture information b. sync pulses c. blanking pulses d. camera signal 675. 81. A lens has an 8-cm focal length and 4-cm diameter. Its f rating is a. 2 b. 4 c. 8 d. 32 676. 82. Which of the following is a possible cause for an abrupt frequency variation in a self – excited transmitter oscillator circuits resulting poor frequency stability to hold a constant frequency oscillation? a. DC and RF AC heating of resistor which cause a change in values b. Heating and expansion of oscillator coil c. Heating of capacitor in the oscillator d. Power supply voltage changes 677. 678. 679. 83. How long does it take to scan 2 picture elements when 400 are scanned in 50 microseconds? a. 25 microsec b. 0.25 microsec c. 2.5 microsec d. 0.5 microsec 680. 84. Anode voltage for the picture tube, developed from the output of the horizontal deflection circuit. a. Yoke voltage b. Flyback voltage c. Aquadag voltage d. Tube voltage 681. 85. The channel spacing in the Philippine FM broadcast standards a. 400 kHz b. 800 kHz c. 600 kHz d. 200 kHz 682. 86. What is the black-and-white or monochrome brightness signal in TV called? a. RGB b. Color subcarrier c. Q an I d. Luminance Y 683. 87. Which of the following is a midband cable TV channel? a. 6 b. 7 c. 14 d. 23 684. 88. What is the primary purpose of an RF amplifier in a receiver? a. to vary the receiver image rejection by utilizing the AGC b. to provide most of the receiver gain c. to develop the AGC voltage d. to improve the receiver’s noise figure 685. 89. The color with the most luminance is a. red b. yellow c. green d. blue 686. 90. It is the light flux intercepted by a one-foot-square surface that is one-foot from a one- candlepower source. a. candela b. footcandle c. lux d. lumens 687. 91. Refers to the possible cause of an abrupt frequency variations in a self-excited transmitter oscillator circuit resulting to a poor frequency stability to hold a constant oscillator. a. poor soldered connections b. heating of capacitor in the oscillator c. DC and AC heating of resistors which cause change in values d. Aging which cause change in condition in parts characteristics 688. 92. It is the difference in intensity between the black parts and white parts of the picture. a. brightness b. hue c. contrast d. illumination 689. 93. The stereophonic subcarrier suppression level in the Philippines standards a. less than 4% modulation of the main carrier b. less than 3% modulation of the main carrier c. less than 2% modulation of the main carrier d. less than 1% modulation of the main carrier 690. 94. The sound IF in a TV receiver is a. 4.5 MHz b. 10.7 MHz c. 41.25 MHz d. 45.75 MHz 691. 95. The circuit the separates sync pulse from the composite video waveforms is a. the keyed AGC amplifier b. a clipper c. an integrator d. a differentiator 692. 693. 96. In the CED system, the disk capacitance varies with the a. pit depth b. disk size c. speed of rotation d. wavelength of the scanning light 694. 97. The final power amplifier in an FM transmitter usually operates class ______. a. AB b. C c. B d. A 695. 98. In a picture tube, it is the total angle that the beam can be deflected without touching the sides of the envelope. a. screen angle b. tube angle c. picture angle d. deflection angle 696. 99. It is necessary to time the scanning with respect to picture information a. flyback b. synchronization c. blanking d. scanning 697. 100. The intermediate frequency used in for FM broadcasting Philippine standards. a. 455 kHz b. 10.7 MHz c. 11.4 MHz d. 12.5 MHz 698. 699. 700. 701. 702. MULTIPLE CHOICE QUESTIONS IN: 703. 704. 705. 706. 707. 708. Test yourself- Exam 1-10 709. Noise Chapter 4 710. Antennas Chapter 6 711. Satellite Communications Chapter 10 712. Optical Fiber Communications 713. Broadcasting 714. Microwave Communications 715. Acoustics 716. Radiation and wave propagation 717. Transmission Fundamentals 718. Wire and Wireless Communications – Chapter 7 719. Modulation – Chapter 3 720. 721. 722. 723. Encod ed By: 724. 725. Garcia, Frederick P. 726. Cagaoan, Neil 727. Mendoza, Darren 728. Puro, Genara Mhariz P. 729. Tan, Virson V. 730. Visaya, Luz Regine B. 731. Test Yourself –Exam 01 732.ECE Board Exam March 1996 733.That dielectric material of an optical fiber surrounding the core 734. Cladding 735. Armor 736. Shield 737. Cover 738.ECE Board Exam March 1996 739.An antenna that is circularly polarized is the ______. 740. parabolic reflector 741. helical 742. Yagi-uda 743. small circular loop 744.ECE Board Exam March 1996 745.A word in telegraphy consist of ______characters plus a word space. 746. 11 747. 7 and ½ 748. 8 749. 5 750.ECE Board Exam March 1996 751.The number of voice band channels in master group per CCITT standard is ______. 752. 300 753. 480 754. 600 755. 120 756.ECE Board Exam March 1996 757.The power of standard test tone is normally ______. 758. 1 dB 759. 0 mW 760. 1 mW 761. 1 W 762.ECE Board Exam March 1996 763.LORAN is a navigational system used primarily for ______. 764. blind landing 765. obtaining your fixes location over large distances 766. automatic collision warning 767. approach control 768.ECE Board Exam March 1996 769.The expander in a companding device provides ______. 770. greater amplification for low signal levels 771. less amplification for low signal levels 772. greater amplification for high signal levels 773. lesser pressure for transmission cables 774.ECE Board Exam March 1996 775.LORAN is a navigation system used primarily for 776. approach control 777. obtaining fixes over large distances 778. blind landing 779. automatic collision warning 780.ECE Board Exam March 1996 781.At what power level does a 1 kHz tone cause zero interference (144 weighted) ? 782. -90 dB 783. -90 dBm 784. 90 dBm 785. 90 dB 786.ECE Board Exam March 1996 787.One character or a sequence of characters forming a part, or the whole of a message with a specific meaning 788. Signs 789. 790. Code 791. Identifier 792.ECE Board Exam March 1996 793.The K-factor under normal atmospheric conditions in a microwave radio data profile calculation is equal to ______. 794. 2/3 795. 0 796. 4/3 797. Infinity 798.ECE Board Exam March 1996 799.What is the IBM’s asynchronous data link protocol designation? 800. 83 B 801. 8A1 / 8B1 802. 93 B 803. 9A1/ 9B1 804.ECE Board Exam March 1996 805.EIRP stands for ______. 806. effective isotropic refracted power 807. effective and ideal radiated power 808. effective isotropic reflected power 809. effective isotropic radiated power 810.ECE Board Exam March 1996 811. The modulation system used for telegraphy is 812. frequency-shift keying 813. two-tone modulation 814. pulse-code modulation 815. single-tone modulation 816.ECE Board Exam March 1996 817.The standard that specifies a balanced interface cable that will operate bit rates up to 10 Mbps with in a span distances up to 1200 m. 818. RS-423A 819. RS-422A 820. RS-550A 821. RS-449A 822.ECE Board Exam March 1996 823.An antenna which is not resonant at a particular frequencies and so can be used over a wide band of frequencies and so can be used over a wide band of frequencies is called 824. aperiodic 825. boresight 826. cassegrain 827. top-loaded 828.ECE Board Exam March 1996 829.A receiver connected to an antenna whose resistance is 50 ohms has an equivalent noise resistance of 30 ohms. What is the receiver’s noise temperature? 830. 754 K 831. 464 K 832. 174 K 833. 293 K 834.ECE Board Exam March 1996 835.______occurs when the microwave beam is at point of grazing over an obstacle. 836. Diffraction 837. Refraction 838. Absorption 839. Reflection 840.ECE Board Exam March 1996 841.Atmospheric condition is controlled by 842. humidity 843. pressure 844. temperature 845. all of these 846.ECE Board Exam March 1996 847.The characteristics impedance of a transmission line does not depend upon its ______. 848. conductor spacing 849. conductor diameter 850. length 851. conductor radius 852.ECE Board Exam March 1996 853.What is the purpose of a beat frequency oscillator (BFO)? 854. Aid in the reception of weak voice-modulated signals 855. Generates a signal, whose frequency is the same as that of the intermediate frequency 856. Generates a 1kHz note for Morse code reception 857. Generates an output, whose frequency differs from that of the intermediate frequency by 1 kHz 858.ECE Board Exam March 1996 859.The point on the satellite orbit, closest to the earth is 860. prograde 861. perigee 862. zenith 863. apogee 864.ECE Board Exam March 1996 865.The potential difference between any exposed structured to ground in any electrical installation should not exceed ______volts RMS. 866. 10 867. 45 868. 0 869. 30 870.ECE Board Exam March 1996 871.The capture area of an antenna is directly proportional to the 872. frequency of the received signal 873. distance between transmitter and receiver 874. gain of the antenna 875. power density of the signal 876.ECE Board Exam March 1996 877.Modems are required to connect computer to telephone lines because ______. 878. telephone company rules required them 879. the telephone network bandwidth is too high 880. none of the above 881. the telephone network will pass direct current 882.ECE Board Exam March 1996 883.The standard reference antenna for the directive gain is ______. 884. elementary doublet 885. isotropic antenna 886. half-wave dipole 887. infinitesimal dipole 888.ECE Board Exam March 1996 889.One hundred twenty µbars of pressure variation is equal to 890. 120 dBSPL 891. 115.56 dBSPL 892. 41.58 dBSPL 893. 57.78 dBSPL 894.ECE Board Exam March 1996 895.It is a spacecraft placed in orbit around the earth carrying onboard microwave receiver and transmitting equipments. 896. Fiber optic equipment 897. Communications satellite 898. Wireless radio system 899. Coaxial cable syste 900.ECE Board Exam March 1996 901.One type of pulse communications system uses pulse that appear as a group, and which vary in number according to the loudness of the voice. This type of pulse modulation is called 902. pulse duration modulation 903. pulse amplitude modulation 904. pulse code modulation 905. pulse position modulation 906.ECE Board Exam March 1996 907.A device to be connected across the headset in telephone receivers to reduce the effects of acoustic shock. 908. Ground 909. Two rectifiers in parallel with opposite polarities 910. Protector 911. Fuse 912.ECE Board Exam March 1996 913.Judgment on the case against an ECE shall become final and executory after 914. 10 days 915. 60 days 916. 30 days 917. 15 days 918.ECE Board Exam March 1996 919.The equivalent noise temperature of the amplifier is 25 K. What is the noise figure? 920. 1.86 921. 0.1086 922. 1.086 923. 10.86 924.ECE Board Exam March 1996 925.The letter-number designation B8E is a form of modulation also known as ______. 926. pilot carrier system 927. independent sideband emission 928. lincomplex 929. vestigial sideband transmission 930.ECE Board Exam March 1996 931.When the transmitting and receiving antennas are in line-of-sight of each other, the mode of propagation is ______wave. 932. space or direct 933. ground 934. surface 935. sky 936.ECE Board Exam March 1996 937.Crosstalk coupling is ______. 938. dBm (disturbing pair) minus dBm (disturbed pair) 939. the difference between readings on a cable pair with a tone and a cable pair without tone read at the far end of a cable 940. signals from one circuit that get into another circuit 941. All of these are true 942.ECE Board Exam March 1996 943.According to the Nyquist theorem, the sampling rate that can be used in a PCM system is ______the highest audio frequency. 944. once 945. eight times 946. twice 947. thrice 948.ECE Board Exam March 1996 949.Passive crossover components cause some frequencies to be delayed with respect to the other frequencies at the crossover point. 950. Phase shift 951. Phase correction 952. Phase-error correction 953. Time alignment 954.ECE Board Exam March 1996 955.A car horn outdoors produces a sound intensity level of 90 dB at 10 ft away. At this distance, what is the sound power in watt? 956. 12 W 957. 0.12 W 958. 0.012 W 959. 1.2 W 960.ECE Board Exam March 1996 961.What is the one principal difference between synchronous and asynchronous transmission? 962. the pulse height are different 963. the clocking is derived from the data in synchronous transmission 964. the clocking is mixed with the data in asynchronous 965. the bandwidth required is different 966.ECE Board Exam March 1996 967.The lowest layer in the ionosphere 968. D 969. F2 970. E 971. F1 972.ECE Board Exam March 1996 973.What is the number of pins in the RS-232C interface? 974. 25 975. 15 976. 20 977. 20 978.ECE Board Exam March 1996 979.SSB transmission requires only ______of the bandwidth for a DSBFC transmission. 980. ¼ 981. 2/3 982. ½ 983. ¾ 984.ECE Board Exam March 1996 985.The method of generating FM used by broadcasting station is 986. direct 987. all of these 988. indirect 989. insertion 990.ECE Board Exam March 1996 991.What is the transmission rate of a system for transmitting the output of a microcomputer to a line printer operating at a speed of 30 lines/minute? Assume that the line printer has 8 bits of data per character and prints out 80 characters/line. 992. 800 bps 993. 400 bps 994. 320 bps 995. 640 bps 996.ECE Board Exam March 1996 997.Communications code is ______. 998. eight bits per character 999. agreed upon in advance between sender and receiver 1000. the same in all modern computers 1001. either seven or eight bits per character 1002. ECE Board Exam March 1996 1003. What is the reference tone level for dBm? 1004. -82 dBm 1005. -85 dBm 1006. -67 dBm 1007. -90 dBm 1008. ECE Board Exam March 1996 1009. A type of an underground antenna is a/an ______antenna. 1010. Hertz 1011. isotropic 1012. parabolic 1013. Marconi 1014. ECE Board Exam March 1996 1015. Which of the following pulse modulation systems is analog? 1016. Delta 1017. Differential PCM 1018. PWM 1019. PCM 1020. ECE Board Exam March 1996 1021. What is the purpose of the receiver’s squelch circuit? 1022. To overcome fluctuations in the level the RF signal arriving at the receiver antenna 1023. To prevent fluctuations in the AGC bias level 1024. To reduce the receiver’s sensitivity to all incoming signals 1025. To prevent amplified noise from reaching the loudspeaker during the absence of an incoming signal 1026. ECE Board Exam March 1996 1027. TACAN is a navigational aid providing ______. 1028. bearing and distance indication 1029. speed and height indication 1030. bearing and weather information 1031. instrument-landing glide paths 1032. ECE Board Exam March 1996 1033. In ______transmission, a unique SYNC character is transmitted at the beginning of each message. 1034. asynchronous 1035. synchronous 1036. digital 1037. analogue 1038. ECE Board Exam March 1996 1039. If the terminating impedance is exactly equal to the characteristic impedance of the transmission line the return loss is ______. 1040. zero 1041. one 1042. infinite 1043. None of these 1044. ECE Board Exam March 1996 1045. What is the main purpose of a communications system? 1046. None of these 1047. To have a frequency assignment 1048. For modulation 1049. To provide an acceptable replica of the information at the destination 1050. ECE Board Exam March 1996 1051. What is meant by antenna gain? 1052. The final amplifier gain minus the transmission line losses (including any phasing lines present) 1053. The ratio of the amount of power produced by the antenna compared to the output power of the transmitter 1054. The ratio of the signal in the backward direction 1055. The numeric ratio relating the radiated signal strength of an antenna to that of another antenna 1056. ECE Board Exam March 1996 1057. Binary communications systems are better because 1058. they can interface directly with the analog telephone network 1059. the components are simpler, less costly, and more reliable 1060. people think better in binary 1061. interstate calls are less costly 1062. 1063. ECE Board Exam March 1996 1064. In the phase shift method, How many circuits must be balanced? 1065. None of these 1066. 1 1067. 4 1068. 2 1069. ECE Board Exam March 1996 1070. The carrier swing necessary to provide 80% modulation in the FM broadcasting band is ______. 1071. 150 kHz 1072. 120 kHz 1073. 60 kHz 1074. 75 kHz 1075. ECE Board Exam March 1996 1076. The correctness and accuracy of the transmitted message content is 1077. verified by the modem 1078. communications system 1079. determined by the sender and receiver 1080. ensured by use of digital technique 1081. ECE Board Exam March 1996 1082. The signal in a channel is measured to be 23 dB while noise in the same channel is measured to be 9 dB. The signal to noise ratio therefore is ______. 1083. 9/23 1084. 23/9 1085. 32 dB 1086. 14 dB 1087. ECE Board Exam March 1996 1088. Three audio waves with 100,200 and 300 volts amplitude respectively, simultaneously modulate a 450 volts carrier. What is the total percent of modulation of the AM wave? 1089. 69 % 1090. 115.5 % 1091. 50% 1092. 83% 1093. ECE Board Exam March 1996 1094. If the percentage modulation of an AM amplifier is 88% and the modulating signal is 1 volt, the carrier has an amplitude of ______. 1095. 1.14 volts 1096. 0.88 volt 1097. 1.88 volts 1098. 0.12 volt 1099. ECE Board Exam March 1996 1100. It consists of a number of dipoles of equal size, equally spaced along a straight line with all dipoles fed in the same phase from the same source. 1101. Log-periodic antenna 1102. Yagi antenna 1103. End-fire array 1104. Broadside array 1105. ECE Board Exam March 1996 1106. Data switching systems. 1107. improve the efficiency of data transfer 1108. are limited to small data networks 1109. required additional lines 1110. are not used in data system 1111. ECE Board Exam March 1996 1112. A type of array antenna which consists of one half-wave driven dipole, one reflector and one director 1113. Hertzian dipole 1114. Yagi-uda 1115. Broadside collinear 1116. Log periodic dipole array 1117. ECE Board Exam March 1996 1118. Power is a ______amount of energy used in specific period of time 1119. large 1120. definite 1121. electrical 1122. relative 1123. ECE Board Exam March 1996 1124. The midrange frequency range of sound is from 1125. 256 to 2048 Hz 1126. 2048 to 4096 Hz 1127. 512 to 2048 Hz 1128. 16 to 64 Hz 1129. ECE Board Exam March 1996 1130. To connect coaxial line to a parallel-wire ______is the best to use. 1131. directional coupler 1132. quarter-wave transformer 1133. balun 1134. slotted line 1135. ECE Board Exam March 1996 1136. In AM, the carrier carries ______intelligence. 1137. no 1138. difference 1139. distorted 1140. same 1141. ECE Board Exam March 1996 1142. Characteristics impedance of a transmission line is the impedance measured at the ______when its length is infinite. 1143. input 1144. shorted end of the line 1145. output 1146. midsection 1147. ECE Board Exam March 1996 1148. Cross modulation on a receiver is eliminated at the 1149. RF stage 1150. mixer stage 1151. IF stage 1152. detector stage 1153. ECE Board Exam March 1996 1154. A speaker cabinet has an internal volume 84,950 cm3. It has a port area on the baffle of 3,230 cm2 and baffle thickness of 19 mm. What is the Helmholtz resonance hertz of this speaker enclosure? 1155. 260 Hz 1156. 245 Hz 1157. 265 Hz 1158. 250 Hz 1159. ECE Board Exam March 1996 1160. What quarterwave transformer will match a 100Ω line to an antenna whose value is 175Ω? 1161. 132.29 Ω 1162. 150 Ω 1163. 16.58 Ω 1164. 137.5 Ω 1165. ECE Board Exam March 1996 1166. The local loop of the telephone system is understood to be 1167. a single piece of wire connecting the subscriber’s telephone set to another telephone set in an adjacent room 1168. a two-wire or four-wire communication circuit between the customer’s premise and central office 1169. a four-wire circuit connecting a facsimile machine to a computer 1170. a group of wires connecting a telephone set to a modem 1171. ECE Board Exam March 1996 1172. In what region of the world is sporadic-E most prevalent? 1173. The equatorial regions 1174. The northern hemisphere 1175. The arctic regions 1176. The polar regions 1177. ECE Board Exam March 1996 1178. The process of assigning PCM codes to absolute magnitudes 1179. Overloading 1180. All of these 1181. Quantizing 1182. Multiplexing 1183. ECE Board Exam March 1996 1184. It is a measure of the microwave power radiated from an antenna as a function of angular direction from the antenna axis. 1185. Antenna pattern 1186. Polarization 1187. Beamwidth 1188. Sidelobes 1189. ECE Board Exam March 1996 1190. It is the made from semiconductor material such as aluminum-galium-arsenide or gallium-arsenide-phosphide. 1191. APD 1192. Injection laser diode 1193. Light emitting diode 1194. Positive-intrinsic-negative 1195. ECE Board Exam March 1996 1196. Which one is not the basic electrical protection measures in the Philippine Electronics Code? 1197. Voltage/ current limiting and interrupting 1198. Undergrounding 1199. Grounding and bonding 1200. Shielding 1201. ECE Board Exam March 1996 1202. What does the noise weighting curve shows? 1203. Noise signals measured with a 144 handset 1204. Power levels of noise found in carrier systems 1205. The interfering effect of other frequencies in a voice channel compared with a reference frequency of one kilohertz 1206. Interfering effects of signals compared with a 3-kHz tone 1207. ECE Board Exam March 1996 1208. What is the difference between phase and frequency modulation? 1209. Is purely theoretical because they are the same in practice 1210. Lies in poorer audio response of phase modulation 1211. Lies in the different definitions of the modulation index 1212. Is too great to make two systems compatible 1213. ECE Board Exam March 1996 1214. When a transmission line uses ground return, it is called a/an ______line. 1215. ungrounded 1216. balanced 1217. unbalanced 1218. grounded 1219. ECE Board Exam March 1996 1220. What is the gain of four identically polarized antennas stacked one above the other and fed in phase? 1221. 3 dB over the gain of one antenna 1222. 10 dB over the gain of one antenna 1223. 4 dB over the gain of one antenna 1224. 6 dB over the gain of one antenna 1225. ECE Board Exam March 1996 1226. The ratio of the level of the modulated output of a transmitter under conditions of standard test modulation to the level of the demodulated output with no modulation applied both measured with the same bandwidth. 1227. Reference audio output 1228. None of these 1229. Audio frequency response 1230. Residual noise level 1231. ECE Board Exam March 1996 1232. The ______filter attenuates signals but passes frequencies below and above that band. 1233. low pass 1234. band pass 1235. band stop 1236. high pass 1237. ECE Board Exam March 1996 1238. In a telephone system, the customer’s telephone directory numbering is from 000 to 999, what is the capacity of the system? 1239. 1000 lines 1240. 100,000 lines 1241. 10,000 lines 1242. 100 lines 1243. ECE Board Exam March 1996 1244. An absorption loss caused by valence electrons in the silica material from which fibers are manufactured. 1245. Modal dispersion 1246. Infrared absorption 1247. Ion resonance absorption 1248. Ultraviolet absorption 1249. ECE Board Exam March 1996 1250. In an FM receiver, which circuit removes amplitude variations? 1251. Exciter 1252. Mixer 1253. Discriminator 1254. Limiter 1255. ECE Board Exam March 1996 1256. A one-hop, full duplex, microwave system in a space diversity arrangement. Determine “how many receivers in all are used?” 1257. 8 1258. 2 1259. 4 1260. 6 1261. ECE Board Exam March 1996 1262. The frequency spectrum of the stereophonic FM signal. 1263. 67 kHz 1264. 59.5 to 74.5 kHz 1265. 19 to 38 kHz 1266. 30 to 53 kHz 1267. ECE Board Exam March 1996 1268. Termination means 1269. result of disconnecting a line from a transmitter 1270. result of cutting both ends of a conductor 1271. looking back impedance of a line with no load 1272. load connected to the output end of a transmission line 1273. ECE Board Exam March 1996 1274. Asynchronous protocol is 1275. message oriented 1276. clock oriented 1277. bit oriented 1278. character oriented 1279. ECE Board Exam March 1996 1280. Transmission lines are either balanced or unbalanced with respect to ______. 1281. negative terminal 1282. input 1283. ground 1284. positive terminal 1285. ECE Board Exam March 1996 1286. What is the velocity factor for non-foam dielectric 50 or 75 ohm flexible coaxial cable such as RG 8, 11, 58 and 59? 1287. 2.70 1288. 0.10 1289. 0.66 1290. 0.30 1291. ECE Board Exam March 1996 1292. Gain of an isotropic antenna 1293. -1 dB 1294. 1 dB 1295. 0 dB 1296. 2 dB 1297. ECE Board Exam March 1996 1298. In measuring noise in a voice channel at a 4 dB test point level, the meter reads -70 dBm (F1A weighted), convert the reading to pWp. 1299. 53 1300. 93 1301. 63 1302. 83 1303. ECE Board Exam March 1996 1304. Power is always ______. 1305. a definite amount of energy 1306. all of these 1307. the rate at which energy is used 1308. expressed in watts 1309. ECE Board Exam March 1996 1310. Radio fading resulting from obstruction losses. 1311. Log normal fading 1312. None of these 1313. Multi-path fading 1314. Rayleigh fading 1315. ECE Board Exam March 1996 1316. After the IF stages have been aligned, the next stage to align in FM receiver is. 1317. local oscillator 1318. limiter stage 1319. RF amplifier 1320. mixer stage 1321. ECE Board Exam March 1996 1322. ______is a device in data transmission to interface data terminal equipment to an analogue transmission line. 1323. RS 232 1324. Connector 1325. Modem 1326. RJ-11 plug 1327. ECE Board Exam March 1996 1328. What is the primary advantage of DSBSC in AM? 1329. Reduce bandwidth over standard AM 1330. All of these 1331. It is simpler to transmit and receive than the standard AM 1332. No transmitter power is wasted in the carrier 1333. 1334. 1335. 1336. 1337. 1338. 1339. 1340. 1341. 1342. 1343. 1344. 1345. 1346. 1347. 1348. 1349. 1350. 1351. 1352. 1353. 1354. 1355. 1356. Test Yourself – Exam 02 1357. ECE Board Exam November 1996 1358. Which frequency band is the standard AM radio broadcast? 1359. HF 1360. UHF 1361. MF 1362. VHF 1363. ECE Board Exam November 1996 1364. A system that performs parallel-to-serial and serial-to-parallel conversion of data link. 1365. DCE 1366. DTE 1367. Modem 1368. PC 1369. ECE Board Exam November 1996 1370. The line control unit (LCU) operates on the data digital form. 1371. Data communications equipment (DCE) 1372. UART 1373. Modem 1374. Data terminal equipment (DTE) 1375. ECE Board Exam November 1996 1376. Quantization noise is caused by 1377. binary coding techniques 1378. serial transmission errors 1379. the synchronization between encoder and decoder 1380. the approximation of the quantized signal 1381. ECE Board Exam November 1996 1382. Speaker is a device that ______. 1383. convert current variations into sound waves 1384. none of these 1385. convert electrical energy to mechanical energy 1386. convert sound waves into current and voltage 1387. ECE Board Exam November 1996 1388. An object farther from a converging lens than its focal point always has an ______image. 1389. virtual 1390. the same in size 1391. inverted 1392. smaller size 1393. ECE Board Exam November 1996 1394. The loss in signal power as light travels down a fiber is 1395. attenuation 1396. propagation 1397. absorption 1398. scattering 1399. ECE Board Exam November 1996 1400. Energy that has neither been radiated into space nor completely transmitted. 1401. Captured waves 1402. Incident waves 1403. Standing waves 1404. Modulated waves 1405. ECE Board Exam November 1996 1406. One of the reasons why FDM is being replaced by TDM is 1407. noise is amplified with voice when an FDM system is used 1408. it is difficult to place channels side by side 1409. there is more time than frequency 1410. Most available frequencies has been used 1411. ECE Board Exam November 1996 1412. Which determines the number of sideband components of FM? 1413. Modulation frequency 1414. Modulation index 1415. Carrier frequency 1416. All of these 1417. ECE Board Exam November 1996 1418. How would one squeeze more channels of communication into TDM frames of standard length? 1419. Shorten the time delay for each channel 1420. Raise the amplitude 1421. Add modulators 1422. Remove the synchronizing pulses 1423. ECE Board Exam November 1996 1424. When one stations is designated as master and rest of the stations are considered slaves message handling is ______. 1425. polling 1426. WAN 1427. LAN 1428. OSI 1429. ECE Board Exam November 1996 1430. How many satellite orbital slots are requested by the Philippine government from ITU? 1431. 2 1432. 6 1433. 5 1434. 3 1435. ECE Board Exam November 1996 1436. The output of a balanced modulator is ______. 1437. LSB and USB 1438. LSB 1439. USB 1440. Carrier 1441. ECE Board Exam November 1996 1442. RS-232, RS-449, RS-530, V, 24 and X.21 are examples of ______. 1443. standards for interfaces between modems and transmission facilities 1444. standards for various types of transmission channels 1445. standards for interfaces between terminals and modems 1446. standards for end to end performance of data communications system 1447. ECE Board Exam November 1996 1448. A special service circuit connecting two private branch exchanges (PBX). 1449. Phantom line 1450. Private line 1451. Tie trunk 1452. Tandem trunk 1453. ECE Board Exam November 1996 1454. What is the baseband frequency of standard FDM basic supergroup? 1455. 312 to 552 kHz 1456. 300 to 600 kHz 1457. 60 to 2540 kHz 1458. 60 to 108 kHz 1459. ECE Board Exam November 1996 1460. What is the data rate of the ISDN Basic access B channel? 1461. 192 kbps 1462. 32 kbps 1463. 64 kbps 1464. 144 kbps 1465. ECE Board Exam November 1996 1466. Which tester is used to measure SWR? 1467. Spectrum analyzer 1468. Multimeter 1469. Reflectometer 1470. Oscilloscope 1471. ECE Board Exam November 1996 1472. What is the transmission rate of a GSM cellular system? 1473. 64 kbps 1474. 240 kbps 1475. 128 kbps 1476. 270 kbps 1477. ECE Board Exam November 1996 1478. A dipole antenna requires to be feed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11 kW. What is the gain in dB obtain by the use of the reflector ? ( Gain referred to this particular dipole) 1479. 4.24 1480. 1.81 1481. 4.75 1482. 2.6 1483. ECE Board Exam November 1996 1484. Pulse carrier at the ratio of 8000 pulse/sec is amplitude modulated by an analog signal this type of modulation is 1485. PAM 1486. ADM 1487. DM 1488. PCM 1489. ECE Board Exam November 1996 1490. What is the applied power if a thermal RF wattmeter is connected to a transmitter through a variable attenuator? The wattmeter reads 84 mW when 15 dB of attenuation is used. 1491. 4.656 watts 1492. 2.656 watts 1493. 3.656 watts 1494. 2.856 watts 1495. ECE Board Exam November 1996 1496. Collects very weak signal from a broadcast satellite 1497. Satellite dish 1498. LNB 1499. Yagi-Uda antenna 1500. Satellite receiver 1501. ECE Board Exam November 1996 1502. A seven-bit character can represent one of ______possibilities. 1503. 14 1504. 64 1505. 128 1506. 7 1507. ECE Board Exam November 1996 1508. The maximum power suggested by KBP on 919-1312 AM broadcast station in Metro Manila is 1509. 10 kW 1510. 20 kW 1511. 15 kW 1512. 5 kW 1513. ECE Board Exam November 1996 1514. A loudspeaker cabinet has an internal volume of 5,184 in3 (84,950 cm3). It has a port area on the baffle of 50 in2 (322.58cm2) and a thickness of 0.70 in (18 mm). What is the Helmholtz resonance, in hertz, of this loudspeaker enclosure? 1515. 250 Hz 1516. 245 Hz 1517. 240 Hz 1518. 255 Hz 1519. ECE Board Exam November 1996 1520. When the clearance above the obstruction is equal to the radii of even Fresnel zone at the point of reflection the RSL 1521. remains the same 1522. is above threshold 1523. is decreased 1524. is increased 1525. ECE Board Exam November 1996 1526. Digital transmission provides a higher level of signal quality than analog transmission because 1527. repeaters regenerate digital pulses and remove distorstion 1528. digital signals are easier to sample than analog signals 1529. digital signals are smaller than analog signals and cannot easily be distorted 1530. analog signals are continuous and not easily distorted. 1531. ECE Board Exam November 1996 1532. A ______interconnects LAN having identical protocols at the physical and data link layers. 1533. All of these 1534. bridge 1535. router 1536. Gateway 1537. ECE Board Exam November 1996 1538. Both frequency and phase modulation utilize ______modulation 1539. Phase 1540. AM and FM 1541. Digital 1542. Angle 1543. ECE Board Exam November 1996 1544. The different angles of entry of light into an optical fiber when the diameter of the core is many times the wavelength of the light transmitter is known as ______. 1545. refraction 1546. sensor 1547. mode 1548. emitter 1549. ECE Board Exam November 1996 1550. An invitation from the primary to a secondary to transmit a message. 1551. Retransmission 1552. Selection 1553. Reuse 1554. Polling 1555. ECE Board Exam November 1996 1556. An agency of the United Nations that formulates standards and recommend practices for all civil aviation 1557. ICAO 1558. CAA 1559. IATA 1560. ATO 1561. ECE Board Exam November 1996 1562. The transformer signal coding method for T1 carrier is 1563. Binary 1564. NRZ 1565. Manchester 1566. Bipolar 1567. ECE Board Exam November 1996 1568. When the value of k increases, the effective result is ______of the equivalent curvatures. 1569. downward curvatures 1570. flattening 1571. bulging 1572. sharp curvature 1573. ECE Board Exam November 1996 1574. An electromagnetic wave consists of 1575. a magnetic field only 1576. both electric and magnetic fields 1577. an electric field only 1578. non-magnetic field only 1579. ECE Board Exam November 1996 1580. In a transmission line, if the maximum current to minimum current ratio is 2:1 what is the ratio of the maximum voltage to minimum voltage? 1581. 4:1 1582. 1:2 1583. 1:4 1584. 2:1 1585. ECE Board Exam November 1996 1586. Satellite signal transmitted from a satellite transponder to earth’s station. 1587. Vertically polarized 1588. Uplink 1589. Downlink 1590. RHCP 1591. ECE Board Exam November 1996 1592. Multiplexing scheme use by baseband transmission. 1593. FDM 1594. Space multiplexing 1595. TDM 1596. Statistical multiplexing 1597. ECE Board Exam November 1996 1598. Which stands for dB relative level? 1599. dBrn 1600. dBm 1601. dBr 1602. dBa 1603. ECE Board Exam November 1996 1604. What is the maximum color TV bandwidth? 1605. 1.6 MHz 1606. 0.5 MHz 1607. 1.0 MHz 1608. 1.3 MHz 1609. ECE Board Exam November 1996 1610. If Ns=250, determine the earth radius k-factor. 1611. 1.98 1612. 1.23 1613. 1.33 1614. 1.29 1615. ECE Board Exam November 1996 1616. Digital modulation technique used in modems. 1617. ASK 1618. PSK 1619. FSK 1620. All of these 1621. ECE Board Exam November 1996 1622. Which of the following is not a baseband signal modulation? 1623. RF carrier 1624. Video System 1625. Audio signal 1626. Binary coded pulses 1627. ECE Board Exam November 1996 1628. The standing wave ratio is equal to ______if the load is properly matched with the transmission line. 1629. 1 1630. 50 1631. 10 1632. 2 1633. ECE Board Exam November 1996 1634. Noise from random acoustic or electric noise that has equal per cycle over a specified total frequency band. 1635. Thermal noise 1636. White noise 1637. Gaussian noise 1638. All of these 1639. ECE Board Exam November 1996 1640. When was the UHF channel (14-83) of television were added? 1641. 1852 1642. 1904 1643. 1947 1644. 1952 1645. ECE Board Exam November 1996 1646. Multiplexing in a time division multiplexer occurs based upon 1647. the position of a frame within the group of frames 1648. the positioning of data within a frame 1649. the priority assigned to a connected device 1650. the activity of a connected device 1651. ECE Board Exam November 1996 1652. Ethernet is baseband system using CSMA/CD operating at 1653. 20 Mbps 1654. 10 Mbps 1655. 30 Mbps 1656. 40 Mbps 1657. ECE Board Exam November 1996 1658. A microwave communications system space loss calculation formula is 1659. 92.4 + 10 log f +20 log d 1660. 94.2 + 10 log f +20 log d 1661. 92.4 + 20 log f +20 log d 1662. 94.2 + 20 log f +20 log d 1663. ECE Board Exam November 1996 1664. Which is the non-resonant antenna? 1665. Broadside Antenna 1666. Folded Dipole 1667. Rhombic antenna 1668. End fire array 1669. ECE Board Exam November 1996 1670. The first commercial satellite 1671. Explorer 1672. Sputnik 1673. Telstar 1674. Early bird 1675. ECE Board Exam November 1996 1676. A quadrature signaling have ______possible states. 1677. 16 1678. 8 1679. 32 1680. 4 1681. ECE Board Exam November 1996 1682. Proposed the use of a clad glass fiber as a dielectric waveguide. 1683. Kao and Keck 1684. Karpon and Keck 1685. Karpon and Bockham 1686. Bockham and Kao 1687. ECE Board Exam November 1996 1688. What band does VSAT first operate? 1689. X-band 1690. C-band 1691. Ku-band 1692. L-band 1693. ECE Board Exam November 1996 1694. What is the method of diversity reception where the signal is transmitted on 2 different frequencies over the same path? 1695. Quadruple 1696. Frequency 1697. Polarization 1698. Space 1699. ECE Board Exam November 1996 1700. The wavelength of light has no role in 1701. Diffraction 1702. Interference 1703. Resolving power 1704. Polarization 1705. ECE Board Exam November 1996 1706. Which of the following filters block FM radio band for TV channels (2 to 13)? 1707. High-pass filter 1708. Band reject filter 1709. Low-pass filter 1710. Band-pass filter 1711. ECE Board Exam November 1996 1712. The standard ASCII 1713. is version II of ASC 1714. is used only in US and Canada 1715. has 132 characters including 32 control characters 1716. is subset of 8-bit EBCDIC code 1717. ECE Board Exam November 1996 1718. Luminous efficiency is least for a 1719. mercury vapor lamp 1720. low-wattage light bulb 1721. high-wattage light bulb 1722. fluorescent tube 1723. ECE Board Exam November 1996 1724. Transmission lines when connected to antenna have 1725. capacitive load 1726. resistive load whose resistance is less than characteristics impedance 1727. resistive load at the resonant frequency 1728. resistive load whose resistance is greater than the characteristic impedance of the line 1729. ECE Board Exam November 1996 1730. What is the free space loss, in dB, between two microwave parabolic antennas 38.0 kilometer apart operating at 7.0 GHz? 1731. 145.6 dB 1732. 138.5 dB 1733. 135.5 dB 1734. 140.89 dB 1735. ECE Board Exam November 1996 1736. What is the equivalent output of a circuit in dBm, if it is has an output of 10 watts? 1737. 10 dBm 1738. 30 dBm 1739. 20 dBm 1740. 40 dBm 1741. ECE Board Exam November 1996 1742. Satellite engine use 1743. liquid fuel 1744. jet propulsion 1745. ion propulsion system 1746. solar jet 1747. ECE Board Exam November 1996 1748. Low-power radar uses 1749. RIMPATT 1750. TRAPATT 1751. Magnetron 1752. IMPATT 1753. ECE Board Exam November 1996 1754. Transmission line must be matched to the load to 1755. transfer maximum voltage to the load 1756. transfer maximum current to the load 1757. reduce the load current 1758. transfer maximum power to the load 1759. ECE Board Exam November 1996 1760. Electromagnetic wave travel at ______in free space. 1761. 300,000 km/sec 1762. 100,000 km/ sec 1763. 400,000 km/sec 1764. 200km/sec 1765. ECE Board Exam November 1996 1766. When electromagnetic wave are propagated through a waveguide, they 1767. are reflected from the walls but do not travel along them 1768. travel along all four walls of the waveguide 1769. travel along the broader walls of the guide 1770. travel through the dielectric without touching the walls 1771. ECE Board Exam November 1996 1772. Codes must be 1773. agreed upon in advance between sender and receiver 1774. eight bit per character 1775. the same in all modern computer 1776. either seven or eighth bits per character 1777. ECE Board Exam November 1996 1778. Combination of modulator, channel and detector. 1779. Transceiver 1780. Discrete channel 1781. T/R channel 1782. Transponder 1783. ECE Board Exam November 1996 1784. What is the stage of the sand becoming silicon? 1785. Hot 1786. Gas 1787. Liquid 1788. Molten 1789. ECE Board Exam November 1996 1790. Noise reduction system used for film sound in movie 1791. dBx 1792. dolby 1793. dBa 1794. dBm 1795. ECE Board Exam November 1996 1796. What is the principal difference between asynchronous and synchronous transmission? 1797. The clocking is mixed with the data in synchronous transmission 1798. The pulse height are difficult 1799. The clocking is derived from the data in synchronous 1800. The bandwidth required is difficult. 1801. ECE Board Exam November 1996 1802. You are measuring a voice channel at a -4 dB test point level, the meter reads -73 dBm (pure test tone) convert the reading in dBmCO. 1803. 16 1804. 18 1805. 22 1806. 12 1807. ECE Board Exam November 1996 1808. What is the type of emission use by standard AM radio broadcast? 1809. A0 1810. F3 1811. A3 1812. A5C 1813. ECE Board Exam November 1996 1814. ______is the average rate of transmission of sound energy in a given direction through a cross sectional area of 1 sq.m. at right angle to the direction. 1815. Sound pressure 1816. Sound intensity 1817. Pressure variation 1818. Loudness 1819. ECE Board Exam November 1996 1820. Top loading is used in an antenna in order to increase its ______. 1821. input capacitance 1822. beamwidth 1823. bandwidth 1824. effective height 1825. ECE Board Exam November 1996 1826. What component in the telephone set has the primary function of interfacing the handset to the local loop? 1827. Varistor 1828. Induction coil 1829. Resistor 1830. Capacitor 1831. ECE Board Exam November 1996 1832. The first passive satellite transponder. 1833. Early bird 1834. Score 1835. Moon 1836. Sputnik 1837. ECE Board Exam November 1996 1838. The primary purpose of the data modem is to 1839. interface analog terminal equipment to analog communications channel 1840. interface digital terminal equipment to analog communications channel 1841. interface analog terminal equipment to digital communications channel 1842. interface digital terminal equipment to digital communications channel 1843. ECE Board Exam November 1996 1844. ______is the out-of-band signaling between toll central offices (Bell System Standard) 1845. 2,000 Hz 1846. 800 Hz 1847. 3,835 Hz 1848. 3700 Hz 1849. ECE Board Exam November 1996 1850. Which symbol indicates that only one sideband is transmitted? 1851. A3E 1852. B8E 1853. C3F 1854. H3E 1855. ECE Board Exam November 1996 1856. A voice-grade circuit using the PTN has an ideal passband of 1857. 0 to 4 Hz 1858. 0 to 4 kHz 1859. 0 to 4 GHz 1860. 0 to 4 MHz 1861. ECE Board Exam November 1996 1862. 1 micron is equal to ______meter(s). 1863. 10-6m 1864. 10-3 m 1865. 106 m 1866. 109 m 1867. ECE Board Exam November 1996 1868. The lowest resistance grounding on earth 1869. Sand 1870. Clay 1871. Surface loam soil 1872. Limestone 1873. ECE Board Exam November 1996 1874. Troposheric scatter uses the frequencies in the ______band. 1875. VLF 1876. UHF 1877. VHF 1878. UF 1879. ECE Board Exam November 1996 1880. The unit of pitch 1881. Decibel 1882. Phon 1883. Mel 1884. Sone 1885. ECE Board Exam November 1996 1886. What kind of receiver is used in converntional telephone handset? 1887. Capacitor 1888. Carbon 1889. Electromagnetic 1890. Ceramic 1891. ECE Board Exam November 1996 1892. Basic speed rate of digital system. 1893. 144 kbps 1894. 1,544 kbps 1895. 64 kbps 1896. 2,048 kbps 1897. ECE Board Exam November 1996 1898. A horizontal antenna is 1899. centrally polarized 1900. vertically polarized 1901. horizontally polarized 1902. perpendicularly polarized 1903. ECE Board Exam November 1996 1904. What is the diameter of a copper wire to be used in a 16 km loop with a dc loop resistance of 100 ohms/km? 1905. 0.108 cm 1906. 1.082 cm 1907. 0.017 cm 1908. 0.0465 cm 1909. ECE Board Exam November 1996 1910. If a fiber optic system has a rise time of 16 ns, the source rise time is 1.5 ns and the detector rise time is 2 ns, what is the cable rise time? 1911. 14 ns 1912. 6 ns 1913. 9 ns 1914. 12.5 ns 1915. ECE Board Exam November 1996 1916. What is the phase delay of an 800 Hz voice signal if the phase shift is 15 degrees? 1917. 1.25 µsec 1918. 52 µsec 1919. 83.33 µsec 1920. 26 µsec 1921. ECE Board Exam November 1996 1922. What is the power loss of a telephone hybrid? 1923. 6 dB 1924. 2 dB 1925. 3 dB 1926. 1 dB 1927. ECE Board Exam November 1996 1928. You are measuring noise in a voice channel at 7 dB test point level. The meter reads -56 dBm (FIA weighted). What is the reading in dBrnc? 1929. 20 1930. 32 1931. 35 1932. 25 1933. ECE Board Exam November 1996 1934. Space diversity transmission means transmitting and receiving on 1935. two or more antennas operating on two different frequencies 1936. two or more identical frequencies 1937. two or more different frequencies 1938. two or more antennas operating on the same frequencies 1939. ECE Board Exam November 1996 1940. Rules governing the transmission of digital information. 1941. Line protocol 1942. Isochronous 1943. Data communications 1944. Digital communications 1945. ECE Board Exam November 1996 1946. A digital identification associated with a cellular system 1947. SAT 1948. ESN 1949. MIN 1950. SIM 1951. ECE Board Exam November 1996 1952. ______is measuring the propagated field strength over the projected service area 1953. Radio sounding 1954. None of these 1955. Radio monitoring 1956. Radio survey 1957. 1958. 1959. 1960. 1961. 1962. 1963. Test Yourself – Exam 03 1964. 1965. ECE Board Exam April 1997 1966. What is the impedance of a balance 4-wire with a diameter of 0.25 cm and spaced 2.5 cm apart using an insulator with a dielectric constant of 2.56? 1967. 1968. A. 100Ω 1969. B. 65Ω 1970. C. 75 Ω 1971. D. 50 Ω 1972. 1973. ECE Board Exam April 1997 1974. What is the impedance in ohms of a transformer marked for 25V, 4W, when the secondary is correctly loaded? 1975. 150 Ω 1976. 156 Ω 1977. 160 Ω 1978. 165 Ω 1979. 1980. 1981. ECE Board Exam April 1997 1982. A single conductor running from the transmitter to the antenna. 1983. RG-8/U 1984. Single line wire 1985. Twin-lead 1986. MIcrostrip 1987. 1988. ECE Board Exam April 1997 1989. If voltage change equal to twice its original value, what is its corresponding change in dB? 1990. 9 dB 1991. 6dB 1992. 10 dB 1993. 3dB 1994. 1995. ECE Board Exam April 1997 1996. To couple a coaxial line to parallel line, it is better to use a ______. 1997. Slotted line 1998. Quarter-wave transformer 1999. Directional Coupler 2000. Balun 2001. 2002. ECE Board Exam April 1997 2003. What is the characteristic impedance of a single wire with a diameter d= 0.25 mm placed at the center between grounded parallel planes separated by 1 mm apart. The wire is held by a material with a velocity factor of 0.75. 2004. 85 Ω 2005. 63 Ω 2006. 50 Ω 2007. 75 Ω 2008. 2009. ECE Board Exam April 1997 2010. If you have available number of power amplifiers with a gain of 100 each, how many such amplifiers do you need to cascade to give an overall gain of 60 dB? 2011. 3 2012. 4 2013. 5 2014. 2 2015. 2016. ECE Board Exam April 1997 2017. ______sets a limit on the maximum capacity of a channel with a give noise level. 2018. Hartley theorem 2019. Shannon-Hartley theorem 2020. Nyquist theorem 2021. Shannon theorem 2022. 2023. ECE Board Exam April 1997 2024. Transmission sent in both directions simultaneously. 2025. Full duplex 2026. Duplex 2027. Half duplex 2028. Simplex 2029. 2030. ECE Board Exam April 1997 2031. Industrial noise frequency is between ______. 2032. 200 to 3000 Mhz 2033. 15 to 160 Mhz 2034. 0 to 10 Khz 2035. 20 Ghz 2036. 2037. ECE Board Exam April 1997 2038. Reference noise temperature. 2039. 70 deg F 2040. 30 deg C 2041. 290 Kelvin 2042. 25 deg C 2043. 2044. ECE Board Exam April 1997 2045. What is the reference frequency of CCITT psophometric noise measurement? 2046. 800 Hz 2047. 1500 Hz 2048. 3400 Hz 2049. 1000 Hz 2050. 2051. ECE Board Exam April 1997 2052. Which does not effect noise in a channel? 2053. None of these 2054. Bandwidth 2055. Temperature 2056. Quantizing level 2057. 2058. ECE Board Exam April 1997 2059. The random and unpredictable electric signal from natural causes, both internal and external to the system is know as ______. 2060. Distortion 2061. Noise 2062. Attenuation 2063. Interference 2064. 2065. ECE Board Exam April 1997 2066. 2067. The most common unit of noise measurement in white noise testing. 2068. 2069. dBw 2070. dBk 2071. dBm 2072. NPR 2073. 2074. ECE Board Exam April 1997 2075. Unit of noise power of psophometer 2076. dBa 2077. pWp 2078. dBm 2079. dBmO 2080. 2081. ECE Board Exam April 1997 2082. 100% modulation in AM means a corresponding increase in total power by: 2083. 25% 2084. 75% 2085. 100% 2086. 50% 2087. 2088. ECE Board Exam April 1997 2089. If the modulation index of an AM wave is doubled, the antenna current is also doubled, the AM system being used is 2090. A5C 2091. A3J 2092. A3H 2093. A3 2094. 2095. ECE Board Exam April 1997 2096. What particular circuit that rids FM of noise? 2097. HPF 2098. Phase shifter 2099. Limiter 2100. LPF 2101. 2102. ECE Board Exam April 1997 2103. What is the advantage of PTM over PAM? 2104. All of these 2105. Low sampling rate is required 2106. Much better noise immunity 2107. Simpler to generate 2108. 2109. ECE Board Exam April 1997 2110. At 100% modulation, the sum fo the effective voltages in both sidebands is equal to ______% of the unmodulated carrier voltage. 2111. 50 2112. 71 2113. 100 2114. 25 2115. 2116. ECE Board Exam April 1997 2117. A carrier signal has ______. 2118. Constant peak amplitude 2119. The information 2120. Frequency range 20-20000 Hz 2121. A varying amplitude 2122. 2123. ECE Board Exam April 1997 2124. Which transmit only one sideband? 2125. A3E 2126. 3AJ 2127. 11BE 2128. H3E 2129. 2130. ECE Board Exam April 1997 2131. The final amplifier of either FM or AM transmitter operates as 2132. Class B 2133. Class C 2134. Class A 2135. Class D 2136. 2137. ECE Board Exam April 1997 2138. Modulation means 2139. Varying of information 2140. Utilization of a single transmission channel to carry multiple signals 2141. Varying of some parameters of a carrier such as its amplitude to transmit information 2142. Transmit pulses in DC form on a copper wire 2143. 2144. ECE Board Exam April 1997 2145. What is the advantage of sidetone? 2146. High transmission efficiency 2147. Results to a strengthened signal 2148. No energy dissipation 2149. Assures that the telephone is working 2150. 2151. ECE Board Exam April 1997 2152. The standard test tone 2153. 0dB 2154. 10 dBm 2155. 0 dBm 2156. 10 dB 2157. 2158. ECE Board Exam April 1997 2159. One (1) Erlang is equal to ______. 2160. 360 CCS 2161. 100 CCS 2162. 36 CCS 2163. 3.6 CCS 2164. 2165. ECE Board Exam April 1997 2166. Transmission of printed material over telephone lines. 2167. Video text 2168. Facsimile 2169. Encoding 2170. Xerox copy 2171. 2172. ECE Board Exam April 1997 2173. 1-CCS is equal to? 2174. 60 2175. 100 2176. 600 2177. 1 2178. 2179. ECE Board Exam April 1997 2180. 1 Erlang is ______. 2181. 1000 TU 2182. 10 TU 2183. 100TU 2184. 1 TU 2185. 2186. ECE Board Exam April 1997 2187. When waves bend away from straight lines of travel, it is called ______. 2188. Refraction 2189. Reflection 2190. Rarefaction 2191. Diffraction 2192. 2193. ECE Board Exam April 1997 2194. Highest frequency that can be used for skywave HF communications between two given points on earth. 2195. Gyro frequency 2196. Maximum usable frequency 2197. Critical frequency 2198. Virtual frequency 2199. 2200. ECE Board Exam April 1997 2201. Electromagnetic radiation theory was profounded by ______. 2202. Sir Edward Appleton 2203. Sir Isaac Newton 2204. James Clerk Maxwell 2205. Michael Faraday 2206. 2207. ECE Board Exam April 1997 2208. Type of transmission path that permits communication in the frequency range from 30 to 60 MHz and over distances form about 1000 to 2000 km. 2209. Ducting 2210. Ionospheric scatter 2211. Microwave 2212. Troposcatter 2213. 2214. ECE Board Exam April 1997 2215. What is the thickest layer of the ionosphere? 2216. E 2217. F1 2218. F2 2219. D 2220. 2221. ECE Board Exam April 1997 2222. Distance traveled by a wave in the time of one cycle. 2223. Hop 2224. Frequency 2225. Wavelength 2226. Crest 2227. 2228. ECE Board Exam April 1997 2229. Which region of the ionosphere is mainly responsible for long distance night time communication? 2230. A layer 2231. D layer 2232. E layer 2233. F layer 2234. 2235. ECE Board Exam April 1997 2236. What is the effective earth’s radius when N=300? 2237. 8500 km 2238. 6370 km 2239. 7270 km 2240. 7950 km 2241. 2242. ECE Board Exam April 1997 2243. The polarization of a discone antenna is _____. 2244. Horizontal 2245. Vertical 2246. Omni 2247. Directional 2248. 2249. ECE Board Exam April 1997 2250. ______is the horizontal pointing angle of an antenna. 2251. Right angle 2252. Angle of elevation 2253. Bandwidth 2254. Azimuth 2255. 2256. ECE Board Exam April 1997 2257. Which is properly terminated antenna? 2258. Rhombic 2259. Hertz 2260. Marconi 2261. Dipole 2262. 2263. ECE Board Exam April 1997 2264. ______is a device that detects both vertically and horizontally polarized signals simultaneously. 2265. Crystal 2266. Orthomode transducer 2267. Light transducer 2268. Optoisolator 2269. 2270. ECE Board Exam April 1997 2271. How much does the radiated power of an antenna increases if its current increased by 3.3 times? 2272. 6.6 times 2273. 3.3 times 2274. 10.89 times 2275. 9.9 times 2276. 2277. ECE Board Exam April 1997 2278. What do you call the energy that was not radiated into space or completely transmitted? 2279. Incident waves 2280. Captured waves 2281. Standing waves 2282. Modulated waves 2283. 2284. ECE Board Exam April 1997 2285. What is the estimated medium wind loading in the Philippines for antenna tower design? 2286. 200 kph 2287. 250 kph 2288. 300 kph 2289. 100 kph 2290. 2291. ECE Board Exam April 1997 2292. The minimum number of turns a helix antenna must have. 2293. 4 2294. 5 2295. 3 2296. 6 2297. 2298. ECE Board Exam April 1997 2299. When testing transmitter to prevent interfering with other stations, which type of antenna must be used? 2300. Dummy antenna 2301. Hertzian antenna 2302. None of these 2303. Void antenna 2304. 2305. ECE Board Exam April 1997 2306. A device that radiates electromagnetic energy and or intercepts electromagnetic radation. 2307. Antenna 2308. Transmitter 2309. Transmission line 2310. Transceiver 2311. 2312. ECE Board Exam April 1997 2313. The frequency of operation of a dipole antenna cut to length of 3.4 m. 2314. 42.9 MHz 2315. 61.3 MHz 2316. 38.5 MHz 2317. 53.5 MHz 2318. 2319. ECE Board Exam April 1997 2320. Full duplex transmission means 2321. One way transmission 2322. 24-hour transmission 2323. Broadcast transmission 2324. Two-way simultaneous transmission 2325. 2326. ECE Board Exam April 1997 2327. Transmission system for a multidrop network 2328. Taken passing 2329. Polling 2330. Switching 2331. CSMA/CD 2332. 2333. ECE Board Exam April 1997 2334. Synchronous modems cost more than asynchronous modem because ______. 2335. They have larger bandwidth 2336. They are larger 2337. The production volume is larger 2338. They have clock recovery circuits 2339. 2340. ECE Board Exam April 1997 2341. What equation defines the composition of an ISDN basic access line? 2342. B+2D 2343. B+D 2344. 2B+2D 2345. 2B+D 2346. 2347. ECE Board Exam April 1997 2348. Modem is referred to as ______. 2349. Universal asynchronous Rx/Tx 2350. Data communication equipment 2351. Universal synchronous Rx/Tx 2352. Data terminal equipment 2353. 2354. ECE Board Exam April 1997 2355. ______character signifies the start of the test for Bisync. 2356. STX 2357. ETX 2358. SOH 2359. BCC 2360. 2361. ECE Board Exam April 1997 2362. What is the reason why companding is employed in PCM systems? 2363. To overcome impulse noise in PCM receivers 2364. To allow amplitude limiting in the receivers 2365. To solve quantizing noise problem 2366. To protect small signals in PCM from quantizing distortion 2367. 2368. ECE Board Exam April 1997 2369. What is framing? 2370. Is concerned of synchronous system 2371. Refers to parallel transmission 2372. Is concerned with the boundaries between characters 2373. Is concerned with individual bits 2374. 2375. ECE Board Exam April 1997 2376. The method of determining the bandwidth of any processing system is ______. 2377. Bandwidth analysis 2378. Frequency spectrum 2379. Spectral analysis 2380. Frequency analysis 2381. 2382. ECE Board Exam April 1997 2383. It is a protocol used to connect the other packet witching network. 2384. X.25 2385. X.50 2386. X.10 2387. X.75 2388. 2389. ECE Board Exam April 1997 2390. Slowest communications hardware product. 2391. Synchronous 2392. Asynchronous 2393. Ethernet 2394. Internet 2395. 2396. ECE Board Exam April 1997 2397. Highest theoretical frequency that can be processed at a sampling rate without aliasing. 2398. Folding frequency 2399. Resonant frequency 2400. Natural frequency 2401. Critical frequency 2402. 2403. ECE Board Exam April 1997 2404. Data is directly on the transmission cable. 2405. Asynchronous 2406. Synchronous 2407. Baseband 2408. Broadband 2409. 2410. ECE Board Exam April 1997 2411. A source code whose average word length approaches the fundamental limit set by the entropy of a discrete memoryless source. 2412. Prefix code 2413. Huffman code 2414. Entropy code 2415. Source code 2416. 2417. ECE Board Exam April 1997 2418. ______sets the limit on the maximum capacity of a channel with a given noise level. 2419. Hartley theorem 2420. Shannon-hartley theorem 2421. Nyquist theorem 2422. Shannon theorem 2423. 2424. ECE Board Exam April 1997 2425. Gateway can interconnect LANs that have ____ protocols and formats. 2426. The same 2427. Different or the same 2428. Totally different 2429. None of these 2430. 2431. ECE Board Exam April 1997 2432. Steps to follow to produce PCM signal. 2433. Quantizing, sampling, and coding 2434. Sampling, quantizing, and coding 2435. Sampling, coding and quantizing 2436. Coding, quantizing and coding 2437. 2438. ECE Board Exam April 1997 2439. Transmission sent in both directions simultaneously. 2440. Full duplex 2441. Duplex 2442. Half duplex 2443. Simplex 2444. 2445. ECE Board Exam April 1997 2446. ______detects the satellite signal relayed from the feed and converts it to an electric current, amplifies and lower its frequency. 2447. Feedhorn 2448. Satellite dish 2449. Satellite receiver 2450. LNB 2451. 2452. ECE Board Exam April 1997 2453. What kind of battery panels are used in some advance satellites? 2454. Gallium Arsenide solar panel 2455. Germanium based panels 2456. Silicon based panels 2457. Gallium Phosphate solar panel 2458. 2459. ECE Board Exam April 1997 2460. Footprint refers to coverage area in the globe 2461. Satellite radiation polarization 2462. Satellite navigation 2463. Satellite radiation pattern 2464. Satellite coverage 2465. 2466. ECE Board Exam April 1997 2467. Asia Sat I covers how many countries in Asia? 2468. 38 2469. 40 2470. 44 2471. 42 2472. 2473. ECE Board Exam April 1997 2474. Insertion loss of connector-type splices for a single-mode fiber cable. 2475. 0.2 dB 2476. 0.3 dB 2477. 0.09 dB 2478. 0.38 dB 2479. 2480. ECE Board Exam April 1997 2481. A non-coherent light source for optical communications system. 2482. PIN Diode 2483. ILD 2484. APD 2485. LED 2486. 2487. ECE Board Exam April 1997 2488. Type of fiber that has the highest modal dispersion 2489. Step-index multimode 2490. Step-index single mode 2491. Graded index mode 2492. Graded index multimode 2493. 2494. ECE Board Exam April 1997 2495. Fiber optic cable operates near ______frequencies. 2496. 800 THz 2497. 20 MHz 2498. 200 MHz 2499. 2 GHz 2500. 2501. ECE Board Exam April 1997 2502. Lifetime of ILD’s 2503. 150,000 h 2504. 100,000 h 2505. 50,000 h 2506. 200,000 h 2507. 2508. ECE Board Exam April 1997 2509. The sound energy per unit area at right angles to the propagation direction per unit time. 2510. Sound intensity 2511. Loudness 2512. Coherence 2513. Sound stress 2514. 2515. ECE Board Exam April 1997 2516. ______is the transmission of sound from one room to an adjacent room thru common walls, floors or ceilings. 2517. Reverberation 2518. Refraction 2519. Flanking transmission 2520. Reflection 2521. 2522. ECE Board Exam April 1997 2523. The sound power level of a jet plane flying at a height of 1 km is 160 dB. What is the maximum sound pressure level on the ground directly below the plane assuming that the aircraft radiates sound equally in all directions? 2524. 59.1 dB 2525. 69.1 dB 2526. 79.1 dB 2527. 89.1 dB 2528. 2529. ECE Board Exam April 1997 2530. Lowest frequency produced by a musical instrument. 2531. Fundamental 2532. Midrange 2533. Period 2534. Harmonic 2535. 2536. ECE Board Exam April 1997 2537. Sound intensity level is ______. 2538. 10 log I/I(ref) 2539. 10 log I(ref)/I 2540. 30 log I/I(ref) 2541. 20 log I/I(ref) 2542. 2543. ECE Board Exam April 1997 2544. Tendency of sound energy to spread. 2545. Reflection 2546. Diffraction 2547. Rarefaction 2548. Refraction 2549. 2550. ECE Board Exam April 1997 2551. ______used to measure speech volume 2552. Volume meter 2553. Audio frequency meter 2554. Volume unit meter 2555. Speech meter 2556. 2557. ECE Board Exam April 1997 2558. What is the local oscillator frequency range commercial AM broadcast if it is equal to 455 KHz. 2559. 540 to 1600 KHz 2560. 0 to 1600 KHz 2561. 995 to 2055 KHz 2562. 0 to 455 KHz 2563. 2564. ECE Board Exam April 1997 2565. TV channels 2, 4 and 5 are known as ______. 2566. Mid band UHF 2567. Low band UHF 2568. High band VHF 2569. Low band VHF 2570. 2571. ECE Board Exam April 1997 2572. ______is the first component of any MATV system to received broadcast signals. 2573. Receiver 2574. Antenna 2575. Filter 2576. Transmitter 2577. 2578. ECE Board Exam April 1997 2579. Mechanism or device which enables the TV camera to move in internal and tilting motion. 2580. Tilting 2581. Scanner 2582. Pan/tilt device 2583. Panning device 2584. 2585. ECE Board Exam April 1997 2586. The allowable deviation ratio of commercial FM broadcast. 2587. 25 2588. 15 2589. 5 2590. 75 2591. 2592. ECE Board Exam April 1997 2593. ______is the time duration for one horizontal trace. 2594. 48µs 2595. 52 µs 2596. 62 µs 2597. 50 µs 2598. 2599. ECE Board Exam April 1997 2600. Which is atmospheric attenuation? 2601. Attenuation due to rain 2602. Attenuation due to other gasses 2603. Attenuation due to mist and fog 2604. Due to water vapor and oxygen 2605. 2606. ECE Board Exam April 1997 2607. A microwave system that requires the use of repeater. 2608. Intervening terrain is favorable 2609. Distances involved are greater 2610. The required reliability is met 2611. All of these 2612. 2613. ECE Board Exam April 1997 2614. What frequency does oxygen causes excessive attenuation 2615. 119 GHz 2616. 183 GHz 2617. 310 GHz 2618. 60 GHz 2619. 2620. ECE Board Exam April 1997 2621. RADAR means 2622. Radio detection and rating 2623. Radio detection and ranging 2624. Radio distance and ranging 2625. Radio delay and ranging 2626. 2627. ECE Board Exam April 1997 2628. A microwave link between the earth station and the down-town terminal. 2629. STL 2630. Uplink 2631. Downlink 2632. Terrestrial link 2633. 2634. ECE Board Exam April 1997 2635. The advantage of periscope antenna in microwave 2636. Minimize interference to and from other neighboring stations 2637. Shorten waveguide link 2638. Reduce tower height 2639. All of these 2640. 2641. ECE Board Exam April 1997 2642. Professional Regulations Commission was created under ______. 2643. PD 323 2644. PD 223 2645. PD 232 2646. RA 223 2647. 2648. ECE Board Exam April 1997 2649. The institutionalization of the continuing Professional Education (CPE) Program of the various regulated profession under the supervision of the Professional Regulation Commission. 2650. E.O. No. 266 2651. E.O. No. 626 2652. E.O. No. 662 2653. P.D. 381 2654. 2655. ECE Board Exam April 1997 2656. The basic law providing for the regulation of radio station, communications in the Philippines and other purposes. 2657. Act. No.`3846 2658. D.O. No. 11 2659. D.O. No. 88 2660. D.O. No. 5 2661. 2662. ECE Board Exam April 1997 2663. Listing of the date and time events, programs , equipment, test, malfunctions and corrections in communication system. 2664. File 2665. Documentation 2666. Reporting 2667. Log 2668. 2669. 2670. 2671. 2672. 2673. Test Yourself – Exam 04 2674. 2675. ECE Board Exam April 1997 2676. Extra-terrestrial noise is observable at frequencies from 2677. 0 to 20 KHz 2678. Above 2 GHz 2679. 8 to 1.43 GHz 2680. 5 to 8 GHz 2681. 2682. ECE Board Exam April 1997 2683. Band of light waves, that are too short to be seen by human eye. 2684. Visible 2685. Infrared 2686. Ultraviolet 2687. Amber 2688. 2689. ECE Board Exam April 1997 2690. Two wires that are bent 90 degrees apart. 2691. Hertz 2692. Dipole 2693. Log-periodic 2694. Rhomic 2695. 2696. ECE Board Exam April 1997 2697. The first symbol in the designation of radio emission under the ITU rules to 2698. Nature of signals modulating the main carrier 2699. Type of information to be transmitted 2700. Bandwidth 2701. Type of modulation of the main carrier 2702. 2703. ECE Board Exam April 1997 2704. Operating method in which the transmission is made alternately in each direction of a telecommunication channel 2705. Semi-duplex operation 2706. Duplex operation 2707. Half-duplex operation 2708. Simplex operation 2709. 2710. ECE Board Exam April 1997 2711. Production of radiation by a radio transmitting station 2712. Monitoring 2713. Emission 2714. Radiation 2715. Transmission 2716. 2717. ECE Board Exam April 1997 2718. The third symbol in the designation of radio emission under the ITU rules refers to 2719. Type of the modulation of the main carrier 2720. Bandwidth 2721. Nature of the signals modulating the main carrier 2722. Type of information to be transmitted 2723. 2724. ECE Board Exam April 1997 2725. A form of telecommunication for the transmission of transient images of fixed or moving objects. 2726. E-mail 2727. Television 2728. Radio 2729. Internet 2730. 2731. ECE Board Exam April 1997 2732. Radiation pattern of a discone. 2733. Unidirectional 2734. Bidirectional 2735. Omnidirectional 2736. Figure of eight 2737. 2738. ECE Board Exam April 1997 2739. Another SEG function that allows a person to be superimposed on another scene. 2740. Visual effect 2741. Wiper 2742. Chroma keying 2743. Special effect generation 2744. 2745. ECE Board Exam April 1997 2746. What signal-to-noise ratio is required for satisfactory telephone services? 2747. 50 dB 2748. 30 dB 2749. 40dB 2750. 20 dB 2751. 2752. ECE Board Exam April 1997 2753. The use of telecommunication for automatic indicating or recording measurement at the distance from the measuring instrument. 2754. Monitoring 2755. Tracking 2756. Telemetry 2757. Telecommand 2758. 2759. ECE Board Exam April 1997 2760. The standard deviation of the variation in the transmission loss of a circuit should not exceed 2761. 3 dB 2762. 1 dB 2763. 5 dB 2764. 0.5dB 2765. 2766. ECE Board Exam April 1997 2767. Noise caused by the thermal agitation of electrons in resistance. 2768. All of these 2769. Thermal noise 2770. Johnson’s noise 2771. White noise 2772. 2773. ECE Board Exam April 1997 2774. Unity gain antenna 2775. Isotropic 2776. Rhombic 2777. Half-wave dipole 2778. Dummy 2779. 2780. ECE Board Exam April 1997 2781. The series of periodically recurrent pulses is modulated in amplitude by the corresponding instantaneous samples. 2782. PFM 2783. PWM 2784. PDM 2785. PAM 2786. 2787. ECE Board Exam April 1997 2788. This type of transmission permits communication in the frequency range from 30 to 60 MHz and over distances from about 1000 to 2000 km. 2789. Troposcatter 2790. Ionospheric scatter 2791. Ducting 2792. Microwave 2793. 2794. ECE Board Exam April 1997 2795. A region in front of a paraboloid antenna. 2796. Transmission zone 2797. All of these 2798. Fraunhofer 2799. Fresnel 2800. 2801. ECE Board Exam April 1997 2802. Designates the sensation of low or high in the sense of the base and treble. 2803. Frequency 2804. Intensity 2805. Pitch 2806. SPL 2807. 2808. ECE Board Exam April 1997 2809. A good example of a pilot tone system used in commercial frequency modulation stations. 2810. FDM 2811. Time division 2812. Stereo multiplexing 2813. Frequency modulation 2814. 2815. ECE Board Exam April 1997 2816. Emission on a frequency or frequencies immediately outside the necessary bandwidth which result from the modulation process except spurious emission. 2817. Radiation 2818. Noise 2819. Out of the band 2820. Interference 2821. 2822. ECE Board Exam April 1997 2823. A helical antenna is used for satellite tracking because of ______. 2824. Broad bandwidth 2825. Good front-to-back 2826. Maneuverability 2827. Circular polarization 2828. 2829. ECE Board Exam April 1997 2830. Background noise is the same as the following except 2831. Impulse noise 2832. White noise 2833. Thermal noise 2834. Gaussian noise 2835. 2836. ECE Board Exam April 1997 2837. Electronic equipment used to measure standing wave ration. 2838. Reflectometer 2839. Wavemeter 2840. Altimeter 2841. Multimeter 2842. 2843. ECE Board Exam April 1997 2844. A single sideband emission in which the degree of carrier suppression enables the carrier to be reconstituted and to be used for demodulation. 2845. Reduce carrier single sideband emission 2846. Half carrier single sideband emission 2847. Full carrier single sideband emission 2848. Standard single sideband emission 2849. 2850. ECE Board Exam April 1997 2851. Station in the mobile service not intended to be used while in motion. 2852. Coast station 2853. Fixed station 2854. Base station 2855. Land station 2856. 2857. ECE Board Exam April 1997 2858. The electric field lines in a plane perpendicular to the earth’s surface. 2859. Elliptical polarization 2860. Circular polarization 2861. Horizontal polarization 2862. Vertical polarization 2863. 2864. ECE Board Exam April 1997 2865. Known to be the first satellite capable to receive and transmit simultaneously. 2866. Score 2867. Syncom I 2868. Telstar 1 2869. Echo1 2870. 2871. ECE Board Exam April 1997 2872. A digital carrier facility used to transmit a DSI-formatted signal at 1.544. Mbps. 2873. T2 2874. T1 2875. T4 2876. T3 2877. 2878. ECE Board Exam April 1997 2879. 12 voice channels are sampled at 8000 sampling rate and encoded into 8 bit PCM word. Determine the rate of the data stream. 2880. 354 kbps 2881. 750 kbps 2882. 768 kbps 2883. 640 kbps 2884. 2885. ECE Board Exam April 1997 2886. The most common device used as a light detector in fiber optic communications system. 2887. LED 2888. Darlington phototransistor 2889. APDs 2890. PIN diode 2891. 2892. ECE Board Exam April 1997 2893. Two resistors, 20kΩ, and 50kΩ are at ambient temperature. Calculate for a bandwidth equal to 100kHz, the thermal noise voltage for the two resistors connected in parallel. 2894. 0.4782µV 2895. 4278 µV 2896. 4.78 µV 2897. 47.8 µV 2898. 2899. ECE Board Exam April 1997 2900. Calculate the energy of the photon of infrared light energy at 1.55µm 2901. 1.28x10-19 J 2902. 1.6 x10-19 J 2903. 1.22 x10-16 J 2904. 1.9 x10-14 J 2905. 2906. ECE Board Exam April 1997 2907. If a fiber optic system has a rise time of 38.55 ns, the source rise time is 12 ns and the detector rise time is 12 ns, what is the cable rise time? 2908. 34.61 ns 2909. 14.55 ns 2910. 52.55 ns 2911. 26.25 ns 2912. 2913. ECE Board Exam April 1997 2914. Nominal voice channel 2915. 20 to 20 KHz 2916. 16 to 16 KHz 2917. 3 to 3 KHz 2918. 4 KHz 2919. 2920. ECE Board Exam April 1997 2921. Two or more antennas separated by 9 wavelengths are used. 2922. Hybrid diversity 2923. Space diversity 2924. Polarized diversity 2925. Frequency diversity 2926. 2927. ECE Board Exam April 1997 2928. Nif stands for 2929. Narrow intermediate frequency 2930. Noise interference figure 2931. Noise improvement factor 2932. Non-intrinsic fugure 2933. 2934. ECE Board Exam April 1997 2935. Any small element of space in the path of a wave may be considered as a source of secondary wavelet. 2936. De Morgan’s Principle 2937. Faraday’s Law 2938. Huygen’s Principle 2939. Fresnel’s Law of optics 2940. 2941. ECE Board Exam April 1997 2942. Modulation in which the modulated wave is always present. 2943. Carrier modulation 2944. Front-end 2945. Continuous modulation 2946. Log-periodic modulation 2947. 2948. ECE Board Exam April 1997 2949. Atmospheric noise is less at severe frequencies above 2950. Audio level 2951. 30 MHz 2952. 10 GHz 2953. 1 GHz 2954. 2955. ECE Board Exam April 1997 2956. At height about 180 km above the earth exist only during daylight. 2957. F2 layer 2958. D layer 2959. E layer 2960. F1 layer 2961. 2962. ECE Board Exam April 1997 2963. Radiation characteristics of a dipole 2964. Figure of eight 2965. Omnidirectional 2966. Bidirectional 2967. Unidirectional 2968. 2969. ECE Board Exam April 1997 2970. Determine the gain of a 6 ft. parabolic dish operating at 1800 MHz. 2971. 30 dB 2972. 11.2 dB 2973. 15.5 dB 2974. 28.17 dB 2975. 2976. ECE Board Exam April 1997 2977. An electromagnetic wave is ______polarized when the electric field lies wholly in one plane containing the direction of propagation. 2978. Horizontally 2979. Linearly 2980. Circularly 2981. Vertically 2982. 2983. ECE Board Exam April 1997 2984. A device that reduces the intensity of light in fiber optics communication systems. 2985. Reducer 2986. Quality factor 2987. Optical attenuator 2988. Compressor 2989. 2990. ECE Board Exam April 1997 2991. Propagation mode of microwave in a waveguide is known as ______. 2992. TM 2993. TE 2994. SW 2995. TEM 2996. 2997. ECE Board Exam April 1997 2998. The width of the frequency band which is just sufficient to ensure the transmission of information at the rate and with the quality required under a specified condition and class of emission. 2999. Occupied bandwidth 3000. Reference frequency 3001. Necessary bandwidth 3002. Frequency tolerance bandwidth 3003. 3004. ECE Board Exam April 1997 3005. A convenient method of determining antenna impedance. 3006. Stub matching 3007. Reactance circle 3008. Smith chart 3009. Trial and error 3010. 3011. ECE Board Exam April 1997 3012. Which of the following fall under the high frequency band of the radio spectrum? 3013. 8.2345 MHz 3014. 150.50 MHz 3015. 2.4555 MHz 3016. 35.535 MHz 3017. 3018. ECE Board Exam April 1997 3019. The electric field lies in a plane parallel to the earth’s surface. 3020. Elliptical polarization 3021. Horizontal polarization 3022. Vertical polarization 3023. Circular polarization 3024. 3025. ECE Board Exam April 1997 3026. The use of telecommunication for the transmission of signals to initiate, modify or terminate functions of equipment at a distance. 3027. Tracking 3028. Telemetry 3029. Telecommand 3030. Space telemetry 3031. 3032. ECE Board Exam April 1997 3033. The product of the power supplied to the antenna and its gain relative to a half- wave dipole in a given direction. 3034. Peak envelope power 3035. ERP 3036. Rated power 3037. Carrier power’ 3038. 3039. ECE Board Exam April 1997 3040. The Ku-band in the satellite service 3041. 14/11 GHz 3042. 30/17 GHz 3043. 8/7 GHz 3044. 6/4 GHz 3045. 3046. ECE Board Exam April 1997 3047. The sinusoidal carrier is pulsed so that one of the binary states is represented by a carrier while the other is represented by its absence. 3048. FSK 3049. ASK 3050. PSK 3051. QAM 3052. 3053. ECE Board Exam April 1997 3054. Width measured in degrees of a major lobes between end of the love at which the relative power is one half (-3dB) its value from the peak of the lobe. 3055. Bandwidth 3056. Wavelength 3057. Radiation 3058. Beamwidth 3059. 3060. ECE Board Exam April 1997 3061. The most common unit of noise measurement in white noise voltage testing. 3062. NPR 3063. dBm 3064. dBW 3065. dBrn 3066. 3067. ECE Board Exam April 1997 3068. Any governmental office responsible in discharging the obligations undertaken in the convention of the ITU and the regulation. 3069. Administration 3070. The union 3071. Country 3072. Telecommunications office 3073. 3074. ECE Board Exam April 1997 3075. A large speaker having a large diameter (15 cm and above) 3076. Coaxial speaker 3077. Woofer 3078. Tweeter 3079. Trixial speaker 3080. 3081. ECE Board Exam April 1997 3082. Coaxial lines are used on those systems operating ______. 3083. Below 2 GHz 3084. At 300 MHz 3085. Above 10KHz 3086. Above 10GHz 3087. 3088. ECE Board Exam April 1997 3089. Determine the dynamic range for a 10 bit sign magnitude code. 3090. 1023 3091. 425 3092. 511 3093. 756 3094. 3095. ECE Board Exam April 1997 3096. A coherent binary phase shift keyed BPSK transmitter operates at a bit rate of 20 Mbps with a carrier to noise ratio C/N of 8.8dB. Find Eb/No. 3097. 73 dB 3098. 62.4 dB 3099. 81.8 dB 3100. 8.8 dB 3101. 3102. ECE Board Exam April 1997 3103. Receives and collects satellite signals form a broadcast satellite. 3104. LNB 3105. Yagi-Uda array 3106. Satellite receiver 3107. Satellite disk 3108. 3109. ECE Board Exam April 1997 3110. What is the effect in over modulated amplitude modulated radio broadcasting transmission? 3111. Interference to adjacent channel 3112. Higher fidelity 3113. Increase noise 3114. Higher audio signal 3115. 3116. ECE Board Exam April 1997 3117. Average power of a radio transmitter supplied to the antenna transmission line by a transmitter during one radio frequency cycle taken under the condition of no modulation. 3118. Peak envelop power 3119. Rated power 3120. Carrier power 3121. Mean power 3122. 3123. ECE Board Exam April 1997 3124. A method of expressing the amplitude of complex non-periodic signals such as speech. 3125. Frequency 3126. Wavelength 3127. Volume 3128. Pitch 3129. 3130. ECE Board Exam April 1997 3131. A government regulation in telecommunication which provide policy to improve the provision of local exchange carrier service. 3132. E.O. 109 3133. Act 3846 3134. E.O. 59 3135. E.O. 546 3136. 3137. ECE Board Exam April 1997 3138. Radio communication operation service between mobile and land stations or between mobile stations. 3139. Land mobile satellite service 3140. Maritime mobile service 3141. Mobile service 3142. Land mobile 3143. 3144. ECE Board Exam April 1997 3145. The smaller the f rating, the _____ light that lens can take in. 3146. More 3147. Intense 3148. Less 3149. Same 3150. 3151. ECE Board Exam April 1997 3152. A radio communications service use in radio regulation between specified fixed points provided primarily for the safety of air navigation and for the regular efficient and economical air transport. 3153. Space operation service 3154. Space service 3155. Aeronautical mobile service 3156. Aeronautical fixed service 3157. 3158. ECE Board Exam April 1997 3159. Harmonic suppressor connected to an antenna. 3160. High pass filter 3161. Low pass filter 3162. Tank circuit 3163. M-derived filter 3164. 3165. ECE Board Exam April 1997 3166. The tendency of the sound energy to spread. 3167. Rarefaction 3168. Reflection 3169. Refraction 3170. Diffraction 3171. 3172. ECE Board Exam April 1997 3173. An earth satellite whose period of revolution is equal to the period of rotation of the earth about its axis. 3174. Geosynchronous 3175. Steerable 3176. Passive 3177. Active 3178. 3179. ECE Board Exam April 1997 3180. A figure of merit used to measure the performance of a radiation detector. 3181. Noise equivalent power 3182. Ripple factor 3183. Safe factor 3184. Quality factor 3185. 3186. ECE Board Exam April 1997 3187. Radio wave concentration in the direction of the signal emitted by a directional antenna. 3188. Back lobe radiation 3189. Side lobe radiation 3190. Major lobe radiation 3191. Transmitted signal 3192. 3193. ECE Board Exam April 1997 3194. What is the channel bandwidth of a standard analogue telephone system? 3195. 300-500 Hz 3196. 1200 kHz 3197. 100-300 Hz 3198. 300-3400 Hz 3199. 3200. ECE Board Exam April 1997 3201. A satellite receives an uplink frequency of ______MHz from a ground station of 3700 MHz. 3202. 8150 MHz 3203. 1475 MHz 3204. 2225 MHz 3205. 5925 MHz 3206. 3207. ECE Board Exam April 1997 3208. The outer conductor of a coaxial transmission line is always grounded at the 3209. Input only 3210. Input and output 3211. Output only 3212. Point of high SWR 3213. 3214. ECE Board Exam April 1997 3215. Sound intensity is given as 3216. df/dP 3217. dE/dp 3218. dA/dP 3219. dP/dA 3220. 3221. ECE Board Exam April 1997 3222. The lowest frequency produced by an instrument. 3223. Harmonic 3224. Fundamental 3225. Midrange 3226. 0 Hz 3227. 3228. ECE Board Exam April 1997 3229. The reflector and director of an antenna array are considered as 3230. Parasitic elements 3231. Transcendental elements 3232. Feed-points 3233. Driven elements 3234. 3235. ECE Board Exam April 1997 3236. The core of the optical fiber has ______. 3237. A medium index of refraction 3238. A lower index of refraction than the cladding 3239. A lower index of refraction than air 3240. A higher index of refraction than the cladding 3241. 3242. ECE Board Exam April 1997 3243. What makes an antenna physically long but electrically short? 3244. Top loading 3245. Adding C in series 3246. Adding L in series 3247. All of these 3248. 3249. ECE Board Exam April 1997 3250. An AM transmitter is rated 100W at 100% modulation. How much power required for the carrier? 3251. 33.33 W 3252. 66.66 W 3253. 83.33 W 3254. 100 W 3255. 3256. ECE Board Exam April 1997 3257. Used for time division multiplexing. 3258. Frequency modulation 3259. Pulsed modulation 3260. SSB 3261. Amplitude modulation 3262. 3263. ECE Board Exam April 1997 3264. A means of beyond the line-of-sight propagation of microwave signal. 3265. Space wave 3266. Microwave link 3267. Troposcatter 3268. Point-to-point 3269. 3270. ECE Board Exam April 1997 3271. Which of the following refers to the smallest beam of satellite antenna’s radiation pattern? 3272. Hemispheric beam 3273. Spot beam 3274. Zone beam 3275. Global beam 3276. 3277. ECE Board Exam April 1997 3278. Theoretical gain of a hertzian dipole 3279. 0 dB 3280. 1.76 dB 3281. 3 dB 3282. 2.15 dB 3283. 3284. ECE Board Exam April 1997 3285. Satellite system or part of a satellite system, consisting of only one satellite and the operating earth station. 3286. Satellite system 3287. Satellite network 3288. Space system 3289. Multi-satellite link 3290. 3291. ECE Board Exam April 1997 3292. The difference between the original and reconstructed signal gives rise to 3293. S factor 3294. Quantizing noise 3295. S/N 3296. Fade margin 3297. 3298. ECE Board Exam April 1997 3299. An area in the memory used for temporary storage of information, on “Last in First out” basis. 3300. Core 3301. Register 3302. Flag 3303. Stack 3304. 3305. ECE Board Exam April 1997 3306. Refers to a land station in a maritime mobile service 3307. Coast station 3308. Ship earth station 3309. Coast earth station 3310. Maritime station 3311. 3312. ECE Board Exam April 1997 3313. Modulation in which no signal is present between pulses 3314. Pulse modulation 3315. QAM 3316. PSK 3317. FSK 3318. 3319. ECE Board Exam April 1997 3320. In the designation of bandwidth and emission, what letter in the first symbol represents a double-sideband type of modulation? 3321. A 3322. B 3323. C 3324. H 3325. 3326. ECE Board Exam April 1997 3327. Loss due to the diffraction of light when it strikes on the irregularities formed during the manufacturing process of the fiber optics. 3328. Absorption loss 3329. Attenuation 3330. Bending loss 3331. Rayleigh scattering loss 3332. 3333. ECE Board Exam April 1997 3334. What is the unit of electric field strength? 3335. Watt/meter 3336. Ohms/meter 3337. Ampere/meter 3338. Watt/meter2 3339. No answer 3340. 3341. ECE Board Exam April 1997 3342. Refers to the first generation of local loop system in telecommunication technology. 3343. GSM 3344. DECT 3345. Analogue cellular 3346. TACS 3347. 3348. ECE Board Exam April 1997 3349. An area on the surface of the earth within which the bore sight of the steerable satellite beam intended to be pointed 3350. Effective boresight area 3351. Countour boresight are 3352. Coordination boresight are 3353. Equivalent boresight area 3354. 3355. ECE Board Exam April 1997 3356. For a sample rate of 40 kHz, determine the maximum analog input frequency 3357. 30 kHz 3358. 40 kHz 3359. 20 kHz 3360. 10 kHz 3361. 3362. ECE Board Exam April 1997 3363. An antenna that can only receive a television signal. 3364. Isotropic antenna 3365. TVRO 3366. Reference antenna 3367. Yagi antenna 3368. 3369. ECE Board Exam April 1997 3370. Halo is also called 3371. Flare 3372. Dark current 3373. Glitch 3374. Ghost 3375. Test Yourself – Exam 05 3376. 3377. ECE Board Exam April 1998 3378. Space diversity transmission means transmitting and receiving on ______. 3379. Two or more antennas operating on two different frequencies 3380. Two or more identical frequencies 3381. Two or more antennas operating on the same frequency 3382. Two or more different frequency 3383. 3384. ECE Board Exam April 1998 3385. An increase in the effective power radiated by an antenna in a certain desired direction at the expense of power radiated in other directions. 3386. Antenna gain 3387. Antenna back lobe ration 3388. Antenna total ration 3389. Antenna efficiency 3390. 3391. ECE Board Exam April 1998 3392. A radio land station in the land mobile service 3393. Mobile station 3394. Land station 3395. Base station 3396. Ship earth station 3397. 3398. ECE Board Exam April 1998 3399. A major and basic advantage for the use of a klystron. 3400. High power 3401. Efficiency 3402. Lesser noise 3403. Cheaper 3404. 3405. ECE Board Exam April 1998 3406. A band where most military satellite often operate 3407. Ku 3408. C 3409. X 3410. L 3411. 3412. ECE Board Exam April 1998 3413. The final power amplifier in an FM transmitter usually operates class ______. 3414. AB 3415. C 3416. B 3417. A 3418. 3419. ECE Board Exam April 1998 3420. In television broadcasting vivid strong colors are often referred as ______. 3421. Saturation 3422. Hue 3423. Chrominance 3424. Luminance 3425. 3426. ECE Board Exam April 1998 3427. Where do the maximum current and minimum voltage values on a resonant Hertz dipole exist? 3428. Center of the antenna 3429. Near the end of the antenna 3430. Near the center of the antenna 3431. Ends of the antenna 3432. 3433. ECE Board Exam April 1998 3434. How can the antenna efficiency of an HF grounded vertical antenna be made comparable to that of a half-wave antenna? 3435. By lengthening the vertical 3436. By installing a good ground radial system 3437. By shortening the vertical 3438. By isolating the coax shield from ground 3439. 3440. ECE Board Exam April 1998 3441. At what distance is VHF propagation normally limited? 3442. Around 500 miles 3443. Around 1500 miles 3444. Around 2000 miles 3445. Around 1000 miles 3446. 3447. ECE Board Exam April 1998 3448. What is meant by the term antenna efficiency? 3449. Efficiency = effective radiated power/transmitter output x 100% 3450. Efficiency = radiation resistance/ transmission resistance 3451. Efficiency = total resistance/radiation resistance x 100% 3452. Efficiency = radiation resistance/total resistance x 100% 3453. 3454. ECE Board Exam April 1998 3455. This is referred to as a fixed radio station that broadcasts program material from studio to transmitter by radio link. 3456. Aural BC intercity relay 3457. Aural broadcast STL 3458. Shortwave station 3459. Remote-pickup 3460. 3461. ECE Board Exam April 1998 3462. What law does a light traveling in air optical fiber follow? 3463. Millman 3464. Snell’s 3465. Maxwell 3466. Huygen 3467. 3468. ECE Board Exam April 1998 3469. Which of the following is designated as the international distress, safety and calling frequency for radio telephony for stations of the maritime mobile service when using frequencies in the authorized bands between 156 and 174 MHz? 3470. 165.8 MHz 3471. 156.8 MHz 3472. 158.6 MHz 3473. 168.5 MHz 3474. 3475. ECE Board Exam April 1998 3476. A device that connects two dissimilar networks and performs the protocol conversion. 3477. Gateway 3478. Coupler 3479. Transformer 3480. Converter 3481. 3482. ECE Board Exam April 1998 3483. The use of telecommunication for the transmission of signals to initiate, modify or terminate functions of equipment at a distance. 3484. Tracking 3485. space command 3486. Telecommand 3487. Trunking 3488. 3489. ECE Board Exam April 1998 3490. Best described a dip-meter. 3491. A variable LC oscillator with metered feedback current 3492. An SWR meter 3493. A counter 3494. A field strength meter 3495. 3496. ECE Board Exam April 1998 3497. Refers to an emission designation for facsimile? 3498. J3E and F4E 3499. A3J and A4E 3500. A3E and F3C 3501. R3E and A3E 3502. 3503. ECE Board Exam April 1998 3504. How does a SSB transmitter output power normally expressed? 3505. Average power 3506. In terms of peak envelop power 3507. In terms of peak-to-peak power 3508. Peak power 3509. 3510. ECE Board Exam April 1998 3511. In satellite communication, the Geostationary satellites are conveniently located with respect to the equator at ______. 3512. 45 degrees latitude 3513. 90 degrees latitude 3514. 0 degrees latitude 3515. 5 degrees latitude 3516. 3517. ECE Board Exam April 1998 3518. Known as the technique for adding a series inductor at or near the center of an antenna element in order to cancel the capacitive reactance of an antenna. 3519. Dipole 3520. Center loading 3521. Reflector 3522. loading coil 3523. 3524. ECE Board Exam April 1998 3525. What is meant by the term antenna bandwidth 3526. Antenna length divided by the number of elements. 3527. The angle between the half-power radiation points 3528. The frequency range over which and antenna can be expected to perform well 3529. The angle formed between two imaginary line drawn through the ends of the elements 3530. 3531. ECE Board Exam April 1998 3532. A multiple access technique used in GSM cellular system 3533. TACS 3534. FDMA 3535. TDMA 3536. CDMA 3537. 3538. ECE Board Exam April 1998 3539. Refers to an effect of selective fading. 3540. A fading effect caused by phase differences between radio wave components of the same transmission, as experienced at the receiving station. 3541. A fading effect caused by small changes in beam heading at the receiving station. 3542. A fading effect caused by the time differences between the receiving and transmitting stations. 3543. A fading effect caused by large changes in the height of the ionosphere, as experienced at the receiving station. 3544. 3545. ECE Board Exam April 1998 3546. Where the voltage node of a half-wave antenna does exists? 3547. At feed point 3548. Near the center 3549. At center 3550. Near the feed point 3551. 3552. ECE Board Exam April 1998 3553. This is a flexible vertical rod antenna commonly used on mobiles. 3554. Marconi 3555. Hertz 3556. Whip 3557. Ground plane 3558. 3559. ECE Board Exam April 1998 3560. Referred to as an average power from the radio transmitter supplied to the antenna transmission line taken during one radio frequency cycle under no modulation. 3561. Carrier power 3562. Rated power 3563. Peak envelop power 3564. Mean power 3565. 3566. ECE Board Exam April 1998 3567. ______is a major cause of the sporadic-E condition 3568. Temperature inversions 3569. Sunspots 3570. Meteors 3571. Wind shear 3572. 3573. ECE Board Exam April 1998 3574. Which of the following refers to a double side band full carrier? 3575. A3E 3576. A3J 3577. F3 3578. R3A 3579. 3580. ECE Board Exam April 1998 3581. What is the basic qualification of an applicant for public carrier network before a certificate of public convenience or a provisional authority is issued? 3582. Franchise 3583. SEC document 3584. Business permit 3585. Radio station license 3586. 3587. ECE Board Exam April 1998 3588. How wide is the spectrum bandwidth of a single GSM carrier? 3589. 100 kHz 3590. 200 kHz 3591. 50 kHz 3592. 16 kHz 3593. 3594. ECE Board Exam April 1998 3595. With which emission type is the capture-effect most pronounced? 3596. CW 3597. FM 3598. SSB 3599. AM 3600. 3601. ECE Board Exam April 1998 3602. What is a dummy antenna? 3603. One which is used as a reference for gain measurements 3604. And antenna used for hand-held radio 3605. An non-directional transmitting antenna 3606. A non-radiating load for a transmitter used for testing 3607. 3608. ECE Board Exam April 1998 3609. Best description of a collinear and broadside antenna radiation pattern. 3610. Bidirectional 3611. Perfect circle 3612. Unidirectional 3613. Omnidirectional 3614. 3615. ECE Board Exam April 1998 3616. A satellite beam that covers almost 42.4% of earths surface. 3617. Spot beam 3618. Global beam 3619. Zone beam 3620. Hemispheric beam 3621. 3622. ECE Board Exam April 1998 3623. The modulation technique used by GSM cellular system 3624. Phase shift keying 3625. Frequency shift keying 3626. Gaussian minimum shift keying 3627. QAM 3628. 3629. ECE Board Exam April 1998 3630. ______generates light beam at a specific visible frequency. 3631. Glass fiber 3632. Infrared 3633. Light waves 3634. Laser 3635. 3636. ECE Board Exam April 1998 3637. The most common application of satellites 3638. Surveillance 3639. Reconnaissance 3640. Defense systems 3641. Communication 3642. 3643. ECE Board Exam April 1998 3644. Referred to the dielectric constant of a transmission line material. 3645. Inductance and capacitance 3646. Velocity factor 3647. Characteristic impedance 3648. Propagation velocity 3649. 3650. ECE Board Exam April 1998 3651. Referred to as a ferrite device that can be used in lieu of a duplexer to isolate a microwave transmitter and receiver when both are connected to the same antenna. 3652. Isolator 3653. Circulator 3654. Coupler 3655. Diode. 3656. 3657. ECE Board Exam April 1998 3658. ______is more prevalent in analog signals that have steep slopes or whose amplitudes vary rapidly. 3659. Peak limiting 3660. Quantization noise 3661. Granular noise 3662. Slope overload 3663. 3664. ECE Board Exam April 1998 3665. Station located on an object which is beyond and is intended to go beyond the major portion of the earth’s atmosphere. 3666. Terrestrial station 3667. Space station 3668. Satellite station 3669. Mobile satellite station 3670. 3671. ECE Board Exam April 1998 3672. A radio frequency in the ultra high frequency band of the radio spectrum band. 3673. 235.50 MHz 3674. 450.50 MHz 3675. 150.50 GHz 3676. 0.31250 GHz 3677. 3678. ECE Board Exam April 1998 3679. Technical study which deals with production, transport and delivery of a quality signal from source to destination. 3680. Transmission system engineering 3681. Communication system engineering 3682. Telephony engineering 3683. Telegraphic engineering 3684. 3685. ECE Board Exam April 1998 3686. It is used to connect computers in the same building or in same area 3687. MAN 3688. LAN 3689. SWITCH 3690. WAN 3691. 3692. ECE Board Exam April 1998 3693. Referred by radio regulation as the station in the mobile service not intended to be used while in motion. 3694. Fixed station 3695. Base station 3696. Land station 3697. Coast station 3698. 3699. ECE Board Exam April 1998 3700. What is the mixing process? 3701. Distortion caused by auroral propagation 3702. The combination of two signals to produce sum and difference frequencies. 3703. The elimination of noise in wideband receiver by phase differentiation 3704. The elimination of noise in a wideband receiver by phase comparison 3705. 3706. ECE Board Exam April 1998 3707. Which of the following systems is not used in radio detection and ranging? 3708. Frequency shift 3709. Frequency modulation 3710. Pulse radar 3711. Amplitude modulation 3712. 3713. ECE Board Exam April 1998 3714. Considered as the main source of an internal noise. 3715. Device imperfection 3716. Thermal agitation 3717. Temperature change 3718. Flicker 3719. 3720. ECE Board Exam April 1998 3721. In shipboard satellite dish antennas system, azimuth is referred as the ______. 3722. 0 to 90 degrees 3723. Vertical aiming of the antenna 3724. North to East 3725. Horizontal aiming of the antenna 3726. 3727. ECE Board Exam April 1998 3728. What is the period of a wave? 3729. The number of degrees in tone cycle 3730. The number of zero crossing in one cycle 3731. The amplitude of the wave 3732. The time required to complete one cycle 3733. 3734. ECE Board Exam April 1998 3735. Is the total useful information processed or communicated over a specific amount of time 3736. Baud rate 3737. Bit rate 3738. Information theory 3739. Throughput 3740. 3741. ECE Board Exam April 1998 3742. What is the approximate percentage of earth coverage of a geostationary satellite at zero degree elevation? 3743. 33.3% 3744. 45.2% 3745. 42.5% 3746. 30.5% 3747. 3748. ECE Board Exam April 1998 3749. This refers to an area in the memory used for temporary storage of information on the basis of “Last in First out”. 3750. Core 3751. Register 3752. Flag 3753. Stack 3754. 3755. ECE Board Exam April 1998 3756. What is a driven element of an antenna? 3757. Always the rearmost element 3758. Always the forwardmost element 3759. The element fed by the transmission line 3760. The element connected to the rotator 3761. 3762. ECE Board Exam April 1998 3763. Which of the following term best described the overload distortion? 3764. Peak limiting 3765. Quantization noise 3766. Granular noise 3767. Slope distortion 3768. 3769. ECE Board Exam April 1998 3770. What do you mean by the outward flow of and energy from any source in the form of radio waves? 3771. Radiation 3772. Emission 3773. Encoding 3774. Tracking 3775. 3776. ECE Board Exam April 1998 3777. Refer to the deviation of the operating frequency of a crystal oscillator from its nominal value due to temperature variations. 3778. Drift 3779. Flash over 3780. Frequency deviation 3781. Deviation ratio 3782. 3783. ECE Board Exam April 1998 3784. Find the product of the following binary number 100 to 101. 3785. 11000 3786. 10100 3787. 10010 3788. 11100 3789. 3790. ECE Board Exam April 1998 3791. Which of the following is and impedance matching ration of coax balun? 3792. 2:8 3793. 1:2 3794. 4:1 3795. 2:1 3796. 3797. ECE Board Exam April 1998 3798. Quantity that do not change when a beam of light enters on e medium to another. 3799. Frequency 3800. Wavelength 3801. Direction 3802. Speed 3803. 3804. ECE Board Exam April 1998 3805. Which of the following described the very early standard that defines binary digits as space/mark line condition and voltage levels? 3806. V.4 3807. V.2 3808. V.1 3809. V.5 3810. 3811. ECE Board Exam April 1998 3812. A form of single sideband emission where the degree of carrier suppression enable the carrier to be reconstituted and be used for demodulation. 3813. Half carrier single sideband emission 3814. Full carrier single sideband emission 3815. Reduced carrier single sideband emission 3816. Double sideband emission 3817. 3818. ECE Board Exam April 1998 3819. An instrument for recording waveforms of audio frequency. 3820. Oscilloscope 3821. Phonoscope 3822. Radioscope 3823. Audioscope 3824. 3825. ECE Board Exam April 1998 3826. How much is the required minimum power output of an international AM BC stations? 3827. 5 kW 3828. 30 kW 3829. 10 kW 3830. 50 kW 3831. 3832. ECE Board Exam April 1998 3833. What is the equivalent of decimal 51 in binary? 3834. 111011 3835. 110011 3836. 111001 3837. 100011 3838. 3839. ECE Board Exam April 1998 3840. One of the first satellite system catering personal based communications services scheduled for operation. 3841. Iridium system 3842. Plutonium system 3843. Indium system 3844. Gallium system 3845. 3846. ECE Board Exam April 1998 3847. What do you call a circuit that controls the magnetron output? 3848. Inverter 3849. Impeller 3850. Modulator 3851. Converter 3852. 3853. ECE Board Exam April 1998 3854. Known as the satellite transmitted signal form a satellite transponder to earth’s station. 3855. Uplink 3856. Down link 3857. RHCP 3858. Vertically polarized 3859. 3860. ECE Board Exam April 1998 3861. Which of the following colors of light rays has the shortest wavelength? 3862. Yellow 3863. Violet 3864. Red 3865. Blue 3866. 3867. ECE Board Exam April 1998 3868. Antenna which is not properly terminated 3869. Isotropic 3870. Non-resonant 3871. Whip 3872. Resonant 3873. 3874. ECE Board Exam April 1998 3875. Term in communication which is referred, “to send out in all direction”. 3876. Announce 3877. Broadcast 3878. Transmit 3879. Media 3880. 3881. ECE Board Exam April 1998 3882. At the ends of a half-wave antenna, what values of current and voltage exist compared to the remainder of the antenna? 3883. Minimum voltage and minimum current 3884. Equal voltage and current 3885. Minimum voltage and maximum current 3886. Maximum voltage and minimum current. 3887. 3888. ECE Board Exam April 1998 3889. One of the following stands for SONET acronym in telecommunication 3890. System optical network 3891. Simple operation network 3892. Synchronous optical network 3893. System operating network 3894. 3895. ECE Board Exam April 1998 3896. How can intermodulation interference between two transmitters in close proximity reduced or eliminated? 3897. Through installing a band-pass filter in the antenna feed line 3898. Through installing terminated circulator or ferrite isolator in the feed line of the transmitter and duplexer 3899. By using a class C final amplifier with high driving power 3900. By installing a low-pass filter in the antenna feed line 3901. 3902. ECE Board Exam April 1998 3903. What propagation condition is usually indicated when a VHF signal is received from a station over 5000 miles away? 3904. Moonbounce 3905. D-layer absorption 3906. Tropospheric ducting 3907. Faraday rotation 3908. 3909. ECE Board Exam April 1998 3910. In radio High frequency communications the higher the radio frequency the ______. 3911. Higher it can reach 3912. Shorter it can reach 3913. Effect is null 3914. Longer it can reach 3915. 3916. ECE Board Exam April 1998 3917. The signal to noise ratio that is required for a satisfactory television reception. 3918. 30 dB 3919. 40 dB 3920. 10 dB 3921. 20 dB 3922. 3923. ECE Board Exam April 1998 3924. What is meant by referring to electromagnetic waves as horizontally polarized? 3925. The electric field is parallel to the earth 3926. Both the electric and magnetic fields are vertical 3927. Both the electric and magnetic fields are horizontal 3928. The magnetic fields is parallel to the earth 3929. 3930. ECE Board Exam April 1998 3931. What is emission F3F? 3932. Facsimile 3933. Modulated CW 3934. RTTY 3935. Television 3936. 3937. ECE Board Exam April 1998 3938. How can receiver desensitizing be reduced? 3939. Increase the receiver bandwidth 3940. Ensure good RF shielding between the transmitter and receiver 3941. Increase the transmitter audio gain 3942. Decrease the receiver squelch, gain. 3943. 3944. ECE Board Exam April 1998 3945. Circuit used to amplify the optical signal in fiber optics communications links. 3946. Attenuator 3947. Optical repeater 3948. Optical amplifier 3949. Generator 3950. 3951. ECE Board Exam April 1998 3952. What do you call the single booster installed on the antenna dish of satellite receiver? 3953. Low noise amplifier 3954. Single amplifier 3955. Noise amplifier 3956. Rectifier 3957. 3958. ECE Board Exam April 1998 3959. Term for the transmission of printed pictures by radio? 3960. Facsimile 3961. ACSSB 3962. Xerography 3963. Television 3964. 3965. ECE Board Exam April 1998 3966. An interfering current in a telegraph or signaling channel due to telegraph or signaling current by another channel. 3967. Crosstalk 3968. Noise current 3969. Crossfire 3970. Intermodulation 3971. 3972. ECE Board Exam April 1998 3973. Where is the noise generated that primarily determines the signal-to-noise ratio in a VHF (150 MHz) marine-band receiver? 3974. In the ionosphere 3975. In the receiver rear end 3976. In the receiver front end 3977. In the atmosphere 3978. 3979. ECE Board Exam April 1998 3980. Known as the data transfer scheme that used handmaking principle. 3981. Synchronous data transfer scheme 3982. DMA data transfer scheme 3983. Asynchronous data transfer scheme 3984. Uninterrupted data transfer scheme 3985. 3986. ECE Board Exam April 1998 3987. Type of modulation used in TV broadcast visual transmitter. 3988. Pulse modulation 3989. DSBFC 3990. Vestigial sideband 3991. SSBFC 3992. 3993. ECE Board Exam April 1998 3994. A transmitter supplies 8 kW to the antenna when it is unmodulated, determine the total radiated power when modulated at 90%. 3995. 5 kW 3996. 20 kW 3997. 15 kW 3998. 8.36 kW 3999. 4000. ECE Board Exam April 1998 4001. Best describe as an amplifier used in radio telephony. 4002. Magnifier 4003. Class B 4004. Class C 4005. Class A 4006. 4007. ECE Board Exam April 1998 4008. The latest government regulation in the telecommunication which provides policy for the provision of local exchange carrier service. 4009. E.O. 546 4010. E.O. 109 4011. Act 3948 4012. E.O. 59 4013. 4014. ECE Board Exam April 1998 4015. Referred to as the stage in the radio receiver that contributes most of the noise. 4016. IF amplifier 4017. Supply stage 4018. Speaker 4019. Mixer 4020. 4021. ECE Board Exam April 1998 4022. The frequency tolerance of an AM radio broadcast station 4023. 200 Hz 4024. 2000 Hz 4025. 20 Hz 4026. 2 Hz 4027. 4028. ECE Board Exam April 1998 4029. What are electromagnetic waves? 4030. A wave consisting of two magnetic fields at right angles to each other 4031. A wave consisting of an electric field and a magnetic field at right angles to each other. 4032. Alternating currents in the core of an electromagnet 4033. A wave consisting of two electric fields at right angles to each other 4034. 4035. ECE Board Exam April 1998 4036. What is the frequency range of C-band? 4037. 10.95 to 14.5 GHz 4038. 27.5 to 31 GHz 4039. 3.4 to 6.424 GHz 4040. 1.53 to 2.7 GHz 4041. 4042. ECE Board Exam April 1998 4043. Determine from the following the basic mode of transmission system in the public data network in which data are transferred from the source to the network and from the network to the destination in the frame format. 4044. Voice mode 4045. Asynchronous mode 4046. Synchronous mode 4047. Packet mode 4048. 4049. ECE Board Exam April 1998 4050. Refers to a type of beam antenna which uses two or more straight elements arranged in line with each other. 4051. Dipole antenna 4052. Yagi antenna 4053. Whip antenna 4054. Rhombic antenna 4055. 4056. ECE Board Exam April 1998 4057. What is a frequency discriminator? 4058. A circuit for filtering two closely adjacent signals 4059. A circuit for detecting FM signals 4060. An FM generator 4061. An automatic bandswitching circuit. 4062. 4063. ECE Board Exam April 1998 4064. These are used to connect non-ISDN equipment ot ISDN line. 4065. Digipeaters 4066. Terminal adapters 4067. Local repeaters 4068. Terminal repeaters 4069. 4070. ECE Board Exam April 1998 4071. The executive branch of government in charge of policy making in the telecommunications. 4072. National telecommunications commission 4073. Telecommunications control bureau 4074. Department of transportation and communications 4075. Bureau of telecommunications 4076. 4077. 4078. 4079. 4080. 4081. 4082. 4083. 4084. 4085. 4086. 4087. 4088. 4089. 4090. 4091. 4092. 4093. 4094. 4095. 4096. 4097. Test Yourself – Exam 06 4098. 4099. ECE Board Exam April 1998 4100. 4101. When adjusting an RF filter on a transmitter using a dummy load, how much watts dissipation should it stand to test a 150 watts transmitter? 4102. 4103. 75 watts 4104. 300 watts 4105. 50 watts 4106. 150 watts 4107. 4108. ECE Board Exam April 1998 4109. When does broadcast station conduct and equipment test? 4110. During day time 4111. During night time 4112. At any time 4113. During experimental period 4114. 4115. ECE Board Exam April 1998 4116. Channel 7 of the regular television channel belongs to which band? 4117. Low VHF band 4118. High VHF band 4119. Low UHF band 4120. High UHF band 4121. 4122. ECE Board Exam April 1998 4123. Which of the following is one of the possible causes for a slow drift of frequency in a self exited transmitter oscillator circuits resulting to a poor frequency stability? 4124. Poor soldered connections 4125. Power supply voltage changes 4126. Loose connections in the oscillator, amplifier, or antenna circuits 4127. DC and RF heating of resistors, causing then to change values. 4128. 4129. ECE Board Exam April 1998 4130. A third symbol radio emission which represent telephone transmission including sound broadcasting. 4131. W 4132. F 4133. C 4134. E 4135. 4136. ECE Board Exam April 1998 4137. Which of the following is not a common microwave application? 4138. Radar 4139. Data transmission 4140. Space communications 4141. Mobile radio 4142. 4143. ECE Board Exam April 1998 4144. Which of the following is referred to as a radio emission without sidebands 4145. Analog 4146. Carrier 4147. Data 4148. Voice 4149. 4150. ECE Board Exam April 1998 4151. Ho w many times bigger does the bandwidth of a fiber optic multimode have over a cable? 4152. 50 times bigger 4153. 100 times bigger 4154. 10 times bigger 4155. 5 times bigger 4156. 4157. ECE Board Exam April 1998 4158. Type of antenna which is normally used for satellite tracking service. 4159. Omni 4160. Helical 4161. Yagi 4162. Dipole 4163. 4164. ECE Board Exam April 1998 4165. One of the following is referred to as a major component of an optical time domain reflectometer 4166. Pulse generator and vertical plate 4167. Laser and horizontal plate 4168. Pulse generator laser 4169. Vertical and horizontal plate 4170. 4171. ECE Board Exam April 1998 4172. One of the commonly used domain in the internet service. 4173. Yahoo 4174. http 4175. com 4176. www 4177. 4178. ECE Board Exam April 1998 4179. What is meant by the term radiation resistance for an antenna? 4180. The resistance in the trap coils to received signal 4181. An equivalent resistance that would dissipate the same amount of power as that radiated from an antenna 4182. The specific impedance of the antenna 4183. Losses in the antenna elements and feed line 4184. 4185. ECE Board Exam April 1998 4186. Referred to an oscillator signal “leak through” from a properly neutralized amplifier such as a master oscillator power amplifier. 4187. Carrier 4188. Stray signal 4189. Back wave 4190. Loss wave 4191. 4192. ECE Board Exam April 1998 4193. An advantage of optic fiber rejecting an induced noise signals from magnetic field or solar storms flux. 4194. Electric hazard 4195. Cross talk 4196. Immunity to noise 4197. Shielding 4198. 4199. ECE Board Exam April 1998 4200. What kind of effect is referred to a varying light producing a varying voltage output of a detector? 4201. Current effect 4202. Voltage effect 4203. Resistive effect 4204. Photovoltaic effect 4205. 4206. ECE Board Exam April 1998 4207. ______is known to be the first satellite capable of receiving and transmitting simultaneously. 4208. Syncom I 4209. Telstar I 4210. Score 4211. Aguila 4212. 4213. ECE Board Exam April 1998 4214. The extremely high frequency (EHF) band is in the radio spectrum range of ______. 4215. 30 to 300 kHz 4216. 30 to 300 GHz 4217. 3 to 30 MHz 4218. 3 to 30 GHz 4219. 4220. ECE Board Exam April 1998 4221. One of the following is not among the advantages of series modulation 4222. No transformer 4223. Suppressed white noise 4224. Simple 4225. Modulates any frequency 4226. 4227. ECE Board Exam April 1998 4228. What do you call the service area of a standard AM broadcast where fading is allowed but not objectionable co-channel interference? 4229. Experimental 4230. Secondary 4231. Tertiary 4232. Primary 4233. 4234. ECE Board Exam April 1998 4235. A third symbol emission which represent television. 4236. C 4237. D 4238. F 4239. A 4240. 4241. ECE Board Exam April 1998 4242. In telecommunications when we call data communications it means the transmission of______. 4243. Voice and video 4244. Voice 4245. Video 4246. Computer data 4247. 4248. ECE Board Exam April 1998 4249. If frequency range of 401.000MHz to 401.050MHz has to be channelized at 12.5 kHz between channel, what is the center of its first channel from the lower limit? 4250. 401.125MHz 4251. 401.00625MHz 4252. 401.025MHz 4253. 401.0125MHz 4254. 4255. ECE Board Exam April 1998 4256. Determine the effective radiated power of 20 kW TV broadcast transmitter whose antenna has a field gain of 2. 4257. 40 kW 4258. 80,000 watts 4259. 40,000 watts 4260. 8,000 watts 4261. 4262. ECE Board Exam April 1998 4263. In indication signal for a handshake form the DCE to the DTE in response to an active condition for the request to send a signal. 4264. Data transmission 4265. Clear to send 4266. Receive data 4267. Data set ready 4268. 4269. ECE Board Exam April 1998 4270. In amplitude modulation technique the unmodulated carrier is referred to as having ______. 4271. 100% modulation 4272. 0% modulation 4273. 50% modulated 4274. Over modulated 4275. 4276. ECE Board Exam April 1998 4277. One of the following is not among the major components required on board ship under the global maritime distress and safety system. 4278. On board radio facilities 4279. Radio operator telegraphy onboard 4280. Shore base facilities 4281. Radio personnel on board 4282. 4283. ECE Board Exam April 1998 4284. In what form does the information of data communications is transmitted between two points? 4285. Alphanumeric form 4286. Alphabetic form 4287. Numeric form 4288. Binary form 4289. 4290. ECE Board Exam April 1998 4291. Width of frequency band just enough to ensure the transmission of information at a required rate and quality required, and under a specified condition and class of emission. 4292. Occupied bandwidth 4293. Transmission bandwidth 4294. Necessary bandwidth 4295. Frequency bandwidth 4296. 4297. ECE Board Exam April 1998 4298. Refers to one of the front end circuit of a VHF TV superheterodyne receiver which is usually a separate circuit coupled to the mixer. 4299. Antenna feed 4300. AGC 4301. RF amplifier 4302. Local oscillator 4303. 4304. ECE Board Exam April 1998 4305. All bits in character are sent and received ______in serial port. 4306. In groups of 3 bits 4307. One at a time 4308. In groups of 2 bits 4309. Simultaneously 4310. 4311. ECE Board Exam April 1998 4312. One of the following is a possible cause of an abrupt frequency variation in a self exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant frequency oscillation. 4313. Heating and expansion of oscillator coil 4314. DC and RF ac heating of resistors which cause change in values 4315. Heating of capacitor in the oscillator 4316. Loose connections in the oscillator, amplifier, or antenna circuits. 4317. 4318. ECE Board Exam April 1998 4319. Which of the following parts of the radio receiver represent the component that extracts the desire RF signal from the electromagnetic wave? 4320. AF amplifier 4321. Antenna 4322. Detector 4323. Crystal 4324. 4325. ECE Board Exam April 1998 4326. It is an average power of a radio transmitter supplied to the antenna transmission line taken during a long sufficient interval of time and compared with the lowest frequency encountered in the modulation, taken under the normal operating conditions. 4327. Carrier power 4328. Rated power 4329. Mean power 4330. Peak envelop power 4331. 4332. ECE Board Exam April 1998 4333. Determine from the following radio frequency that falls under the very high frequency band of the radio spectrum. 4334. 345.00 MHz 4335. 144.50 MHz 4336. 235.50 MHz 4337. 450.00 MHz 4338. 4339. ECE Board Exam April 1998 4340. What is the typical number of bits in a static memory location? 4341. 1 4342. 2 4343. 16 4344. 8 4345. 4346. ECE Board Exam April 1998 4347. What controls the contrast of a television cathode ray picture? 4348. AFC 4349. video stage gain 4350. Audio gain control 4351. CRT bias 4352. 4353. ECE Board Exam April 1998 4354. Determine the dB gain of a receiving antenna which delivers a microvolt signal to a transmission line over that of an antenna that delivers a 20 microvolt signal under identical circumstances. 4355. 10 dB 4356. 6 dB 4357. 3 dB 4358. 8 dB 4359. 4360. ECE Board Exam April 1998 4361. Refers to one of a commonly used internet service domain. 4362. www 4363. http 4364. gov 4365. infoseek 4366. 4367. ECE Board Exam April 1998 4368. A law that specifically requires the service of a duly registered electronics and communications engineer in the designing installation and construction, operation and maintenance of radio stations. 4369. Act 3846 4370. LOl 1000 4371. R.A. 5734 4372. Dept. order 88 4373. 4374. ECE Board Exam April 1998 4375. Which band does channel 14 of the television channel belong? 4376. High VHF band 4377. EHF band 4378. UHF band 4379. Low VHF band 4380. 4381. ECE Board Exam April 1998 4382. How many ship’s area is designated in the implementation of the global maritime distress and safety system. 4383. Four 4384. Six 4385. Three 4386. Two 4387. 4388. ECE Board Exam April 1998 4389. What kind of receiver is used in conventional telephone handset? 4390. Capacitor 4391. Electromagnetic 4392. Carbon 4393. Ceramic 4394. 4395. ECE Board Exam April 1998 4396. Determine the lower half-power frequency of a class-C amplifier having upper half-power frequency of 10.025 MHz, a resonant frequency 5 MHz and a circuit Q of 10. 4397. 1.0025 MHz 4398. 10.525 MHz 4399. 0.5 MHz 4400. 10 MHz 4401. 4402. ECE Board Exam April 1998 4403. This is referred to a product of simultaneous frequency and amplitude modulation or a carrier frequency variation which produces unwanted distortion. 4404. Absorption modulation 4405. Simultaneous modulation 4406. Dynamic instability 4407. Series modulation 4408. 4409. ECE Board Exam April 1998 4410. Main basic components of a data communication are composed of the following. 4411. Computer, modern and router 4412. Computer, bridge and gateway 4413. Transmitter, channel and receiver 4414. Transmitter, computer and modem 4415. 4416. ECE Board Exam April 1998 4417. The international radio consultative committee is referred to in international radio communication as ______. 4418. IRCC 4419. ITU 4420. IRR 4421. CCIR 4422. 4423. ECE Board Exam April 1998 4424. Refers to a continuous tone generated in a local exchange terminal through a combination of two frequencies 350 Hz, and 440 Hz. 4425. Busy tone 4426. Call waiting tone 4427. Dial tone 4428. Standard tone 4429. 4430. ECE Board Exam April 1998 4431. One of the advantages of fiber optic which is referred to the volume of capacity of signals it can carry. 4432. Security 4433. Weight 4434. Bandwidth 4435. Physical size 4436. 4437. ECE Board Exam April 1998 4438. Assume a frequency range of 401.000 MHz to 401.050 MHz, if you apply 25 kHz channeling plan, determine the center frequency of the first channel from the lower limit. 4439. 401.010 MHz 4440. 401.0125 MHz 4441. 401.025 MHz 4442. 401.00625 MHz 4443. 4444. 50 ECE Board Exam April 1998 4445. The stability of transmitted signal from a simple Hartley oscillator single transmitter which is coupled to and antenna wire affected by ______. 4446. Chirping of oscillator 4447. Closer coupling between the oscillator and the antenna. 4448. Location of antenna 4449. Material of antenna 4450. 4451. ECE Board Exam April 1998 4452. Refers to the first symbol in an emission designation with an amplitude modulated main carrier represented by letter H. 4453. Single sideband suppressed carrier 4454. Double sideband full carrier 4455. Independent sideband 4456. Double sideband 4457. 4458. ECE Board Exam April 1998 4459. Assume a frequency range of 405.0125 MHz to 405.0875 MHz and 25 kHz channeling plan, determine the center frequency of the second channel from the lower limit. 4460. 405.030 MHz 4461. 405.025 MHz 4462. 405.050 MHz 4463. 405.075 MHz 4464. 4465. ECE Board Exam April 1998 4466. An entity, relying on the transmission, switching and local distribution facilities of local exchange and inter-exchange operators, and overseas carriers, offers enhanced services beyond those ordinarily provided by such carriers. 4467. International carrier 4468. Value-added service provided 4469. Inter-exchange carrier 4470. Local exchange carrier 4471. 4472. ECE Board Exam April 1998 4473. Which of the following refers to full duplex transmission? 4474. One at a time transmission 4475. Two transmission medium 4476. Intermittent transmission 4477. Two way simultaneous transmission 4478. 4479. ECE Board Exam April 1998 4480. What is the first symbol of a radio signal transmission having an amplitude modulated signal carrier, double side band? 4481. C 4482. B 4483. H 4484. A 4485. 4486. ECE Board Exam April 1998 4487. Best choice of transmission line component to couple a coaxial line to a parallel- wire line 4488. Shorting 4489. Balun 4490. Slotted line 4491. Directional coupler 4492. 4493. ECE Board Exam April 1998 4494. Which of the following refers to the video signal amplitude that determines the quality of the picture? 4495. Chrominance 4496. Luminance 4497. Brightness 4498. Contrast 4499. 4500. ECE Board Exam April 1998 4501. ______is the method of encoding audio signals used in US standard 1544 kbit/s 24 channel PCM systems. 4502. Shannon’s law 4503. A-law 4504. Newton’s law 4505. Mu-law 4506. 4507. ECE Board Exam April 1998 4508. In radio regulation, the first symbol in the designation of radio emission is ______. 4509. Bandwidth 4510. Nature of signal(s) modulation the main carrier 4511. Type of modulation of the main carrier 4512. Type of information to be transmitted 4513. 4514. ECE Board Exam April 1998 4515. Who is the principal administrator of republic act 7925? 4516. BOC 4517. DOTC 4518. Congress 4519. NTC 4520. 4521. ECE Board Exam April 1998 4522. What is the term for the ration of the radiation resistance of an antenna to the total resistance of the system? 4523. Effective radiated power 4524. Beamwidth 4525. Radiation conversion loss 4526. Antenna efficiency 4527. 4528. ECE Board Exam April 1998 4529. Where does the AM broadcast band located in the spectrum band? 4530. HF band 4531. VHF band 4532. LF band 4533. MF band 4534. 4535. ECE Board Exam April 1998 4536. What determines the velocity factor in transmission line? 4537. The center conductor resistivity 4538. Dielectrics in the line 4539. The termination impedance 4540. The line length 4541. 4542. ECE Board Exam April 1998 4543. Refers to an address that identifies a server on the network and a particular document on the server 4544. Hypertext 4545. HTML 4546. Wide area network 4547. Uniform resource locator 4548. 4549. ECE Board Exam April 1998 4550. Type of emission produced by one of the early radio transmitter in trains of damped RF ac waves where its oscillator is coupled to a long wire antenna, normally used in radio telegraph and having sidebands on its carrier. 4551. Digital emission 4552. Key emission 4553. Cycle emission 4554. Spark emission 4555. 4556. ECE Board Exam April 1998 4557. Is a kind of satellite which has a period of revolution equivalent to the period of rotation of the earth about its axis. 4558. Passive satellite 4559. Synchronous satellite 4560. Active satellite 4561. Geosynchronous satellite 4562. 4563. ECE Board Exam April 1998 4564. Electromagnetic waves of frequencies arbitrarily lower than 3,000 GHz, propagated in space without artificial guide. 4565. Space waves 4566. Terrestrial waves 4567. Mobile 4568. Hertzian waves 4569. 4570. ECE Board Exam April 1998 4571. Frequencies above ______kHz, are referred to as the radio frequencies. 4572. 20 4573. 2 4574. 10 4575. 200 4576. 4577. ECE Board Exam April 1998 4578. Who is responsible in the correctness and accuracy of transmitted information content over a data communication? 4579. The channel 4580. The transmitter and receiver 4581. The modem 4582. The bridge 4583. 4584. ECE Board Exam April 1998 4585. What is meant by the term deviation ratio? 4586. The ratio of the carrier center frequency to the audio modulating frequency 4587. The ratio of the highest audio modulating frequency to the average audio modulating frequency 4588. The ratio of the maximum carrier frequency deviation to the highest audio modulation frequency 4589. The ratio of the audio modulating frequency to the center carrier frequency 4590. 4591. ECE Board Exam April 1998 4592. A quarter wavelength devices made of crystalline calcite that changes polarization in the optic fiber communication. 4593. Isolator 4594. Retarder 4595. Polarizer 4596. Filters 4597. 4598. ECE Board Exam April 1998 4599. Known as the maritime communications law which was enacted December 5, 1927 4600. R.A. No. 109 4601. R.A. No. 3396 4602. R.A. No. 7925 4603. R.A. No. 3846 4604. 4605. ECE Board Exam April 1998 4606. How do you transmit through multiplexing, a thousand of voice channel information over a single fiber optic using on e wavelength? 4607. Polar division 4608. Time division 4609. Fiber division 4610. Frequency division 4611. 4612. ECE Board Exam April 1998 4613. In regulation of public telecommunications carrier such as in the evaluation of new entrant, the following consideration shall be given emphasis to ______. 4614. Legal, technical and citizenship 4615. Technical, citizenship and kind of service 4616. Citizenship, capacity and financial 4617. Technical, legal and financial 4618. 4619. ECE Board Exam April 1998 4620. One of the following is a high powered RF ac basic transmitter that has two or more stages, the oscillator stage which determines the frequency opereation and RF amplifier stage or stages that develop the high power output. The purpose of which is to develop a good frequency stability. 4621. Goldsmith 4622. MOPA 4623. Alexanderson 4624. Hartley 4625. 4626. ECE Board Exam April 1998 4627. What is the meaning of the term velocity factor of a transmission line? 4628. The index of shielding for coaxial cable 4629. The velocity of the wave on the transmission line multiplied by the velocity of light in vacuum 4630. The ratio of the characteristic impedance of the line to the terminating impedance 4631. The velocity of the wave on the transmission line divided by the velocity of light in a vacuum 4632. 4633. ECE Board Exam April 1998 4634. Which of the following determines the characteristics of a transmission line? 4635. Inductance 4636. Capacitance 4637. Physical dimension 4638. Length 4639. 4640. ECE Board Exam April 1998 4641. One of the following is among the types of fiber optics used in electronics communication. 4642. Step-index multimode 4643. Graded-index multimode 4644. Semi-graded multimode 4645. Single mode 4646. 4647. ECE Board Exam April 1998 4648. Which of the following refers to the smallest beam of a satellite antenna’s radiation pattern 4649. Global beam 4650. Spot beam 4651. Zone beam 4652. Hemispheric beam 4653. 4654. ECE Board Exam April 1998 4655. One of the FM signal generator control which varies the phase of the modulating voltage applied to the oscillator of the sweep generator 4656. Band control 4657. Phase control 4658. Marker amplitude control 4659. Sweep output control 4660. 4661. ECE Board Exam April 1998 4662. What consists the front-end circuit of a VHF TV superheterodyne receiver? 4663. Mixer, RF amplifier and AFC? 4664. RF amplifier, Band pass filter and mixer 4665. Local oscillator, mixer and RF amplifier 4666. Local oscillator, AGC and antenna 4667. 4668. ECE Board Exam April 1998 4669. One of the following prevents a transmitter from emitting a signal that interferes with other stations on frequency during the test. 4670. Use of low height antenna 4671. Use of grounded antenna 4672. Use of dummy antenna 4673. Use of shielded antenna radiator 4674. 4675. ECE Board Exam April 1998 4676. A transmission line consisting of two conductors that have equal resistance per unit length. 4677. Unbalanced line 4678. Open-wire line 4679. Balanced line 4680. Coaxial line 4681. 4682. ECE Board Exam April 1998 4683. How do you eliminate radio frequency variation of an oscillator transmitter caused by its supply voltage? 4684. Use new power supply 4685. Lossen power supply shielding 4686. Use of regulated power supply 4687. Use of high capacitor in the supply circuit 4688. 4689. ECE Board Exam April 1998 4690. Which of the following is not common transmission line impedance? 4691. 50 ohms 4692. 120 ohms 4693. 75 ohms 4694. 650 ohms 4695. 4696. ECE Board Exam April 1998 4697. How do you reduce the loss that is produced when light strikes a flat polished end of a fiber optic? 4698. By painting the surface 4699. By inclining the surface 4700. By cooling 4701. By application of antireflection coating 4702. 4703. ECE Board Exam April 1998 4704. Best reason for pressurizing waveguides with dry air 4705. To maintain propagation 4706. To maintain temperature of the waveguide 4707. To reduce the possibility of internal arcing 4708. To increase the speed of propagation 4709. 4710. ECE Board Exam April 1998 4711. What is the device used in fiber optic communication which consist of a receiver transmitter use to clean up and amplify digital data moving in one direction and another in the opposite direction? 4712. Optic compressors 4713. Optic retarders 4714. Optic isolator 4715. Optic regenerators 4716. 4717. ECE Board Exam April 1998 4718. Which of the following refers to the first active satellite? 4719. Telstar I 4720. Echo I 4721. Intelsat I 4722. Sputnik I 4723. 4724. ECE Board Exam April 1998 4725. In modulation technique, which of the following is referred to audible pitch? 4726. Width 4727. Frequency 4728. Harmonic 4729. Amplitude 4730. 4731. ECE Board Exam April 1998 4732. What do you call the phenomenon in digital circuits that describe the duration of time a digital signal passes a circuit? 4733. Transmission time 4734. Elapsed time 4735. Propagation delay 4736. Travel delay 4737. 4738. ECE Board Exam April 1998 4739. What is the major cause of atmospheric or static noise? 4740. Sunspots 4741. Airplanes 4742. Meteor showers 4743. Thunderstorm 4744. 4745. ECE Board Exam April 1998 4746. Which of the following is not referred to as data terminal equipment? 4747. Telephone set 4748. Printers 4749. Modem 4750. Computer 4751. 4752. ECE Board Exam April 1998 4753. ______is referred as the difference between available power and power budget? 4754. Fade margin 4755. Power margin 4756. Nominal gain 4757. Power dissipation 4758. 4759. ECE Board Exam April 1998 4760. The conversion of digital signal into analog for purposes of transmitting into the telephone line is done through ______. 4761. ISDN 4762. Radio 4763. RS232C 4764. Modem 4765. 4766. ECE Board Exam April 1998 4767. Refers to the duration occupancy period of call during its use. 4768. Occupancy period 4769. Traffic time 4770. Use time 4771. Holding time 4772. 4773. ECE Board Exam April 1998 4774. In data communication the transmission of binary signals will require ______. 4775. Same bandwidth as analog 4776. More bandwidth than analog 4777. Less bandwidth than analog 4778. Bigger cable diameter 4779. 4780. ECE Board Exam April 1998 4781. Assuming a UHF frequency range of 405.0125 MHz to 405.0875 MHz at 25 kHz channeling plan, how many channels can you produce? 4782. 2.5 ch. 4783. 2 ch. 4784. 4 ch. 4785. 3 ch. 4786. 4787. ECE Board Exam April 1998 4788. One of the following is a possible cause for a slow drift of frequency in a self- exited transmitter oscillator circuits resulting to a poor frequency stability. 4789. Loose shielding 4790. Heating of capacitor in the oscillator 4791. Poor soldered connections 4792. Faulty capacitor, resistor, tubes or resistors 4793. 4794. ECE Board Exam April 1998 4795. A modulation which does not follow the sine wave pattern, it produces undesirable harmonics such as spurious emission 4796. 0% modulated 4797. Over-modulated 4798. Unmodulated 4799. 100% modulated 4800. 4801. 4802. 4803. 4804. 4805. 4806. Test Yourself – Exam 07 4807. 4808. 1. How far away is the radio horizon of an antenna 100ft high? 4809. A. 14.14 mi = √2(100ft) 4810. B. 40km 4811. C. 14.14 km 4812. D. 40 mi 4813. 4814. 2. What is the maximum line-of-sight distance between a paging antenna 250 ft high and a pager receiver 3.5ft of the ground? 4815. A. 25 km 4816. B.25mi = √2(250ft) + √2(3.5ft) 4817. C. 70.73 km 4818. D. 70.73 mi 4819. 4820. 3. What is the path attenuation between transmitter and receiver at a frequency of 1.2 Ghz and a distance of 11,000 mi? 4821. A. 119 dB 4822. B. 115dB 4823. C. 179dB = 96.6 + 20log(11000mi) + 20log(1.2GHz) 4824. D. 174dB 4825. 4826. 4. What is the uplink receiver frequency if the downlink transmitter is on channel 4 (3.84 Ghz)? 4827. A. 6.065 GHz 4828. B. 6.84 GHz 4829. C. 6.65 GHz 4830. D. 6.05 GHz 4831. 4832. 5. What is the maximum theoretical data rate of the above problem if one transponder is used for binary transmission? 4833. A. 36 Mbps 4834. B. 72 Mbps 4835. C.18 Mbps 4836. D. 144 Mbps 4837. 4838. 6. What is the guardband between transponder channels in the commercial C-band for satellite communications? 4839. A. 6 MHz 4840. B. 36 MHz 4841. C. 4 MHz 4842. D. 2 MHz 4843. 4844. 4845. 4846. 4847. 4848. 7. What is the typical satellite transponder bandwidth? 4849. A. 24 MHz 4850. B. 500 MHz 4851. C. 36 MHz 4852. D. 48 MHz 4853. 4854. 8. What is the bandwidth available in the commercial C-band? 4855. A. 1000 MHz 4856. B. 36 MHz 4857. C. 250 MHz 4858. D. 500 MHz 4859. 4860. 9. Which of the following is the uplink frequency in C-band? 4861. A. 5.925 GHz 4862. B. 4.2 GHz 4863. C. 7.425 GHz 4864. D. 3.7 GHz 4865. 4866. 10. How many transponder channels are realized in the commercial C-band without frequency re-use? 4867. A. 24 4868. B. 12 4869. C. 36 4870. D. 48 4871. 4872. 11. Which band of frequencies used by military for its satellites and radar? 4873. A. C band 4874. B. X band 4875. C. L band 4876. D. P band 4877. 4878. 12. For navigation as well as marine and aeronautical communications and radar, ____ band is used. 4879. A. L 4880. B. K 4881. C. S 4882. D. J 4883. 4884. 13. What is the current frequency band given most attenuation for satellite communications? 4885. A. Ku 4886. B. C band 4887. C. J 4888. D. P 4889. 4890. 4891. 14. What satellite subsystem monitors onboard conditions such as temperature and battery voltage and transmits this data back to a ground station for analysis? 4892. A. Communications subsystem 4893. B. AKM 4894. C. TTC 4895. D. Transponder 4896. 4897. 15. Which of the following satellite subsystem provides stabilization in orbit and senses changes in orientation? 4898. A. Attitude control subsystem 4899. B. TTC 4900. C. AKM 4901. D. Transponder 4902. 4903. 16. What is the typical center frequency spacing between adjacent channels (transponders) in satellites? 4904. A. 36 MHz 4905. B. 40 MHz 4906. C. 500 MHz 4907. D. 4 MHz 4908. 4909. 17. Which of the following are uplinks in the Ku band? 4910. A. 14 to 14.5 GHz 4911. B. 11.7 to 12.2 GHz 4912. C. 14 to 15.5 GHz 4913. D. 11 to 11.5 GHz 4914. 4915. 18. What is considered as the most advanced satellite system developed for cellular telephones? 4916. A. Iridium 4917. B. Globalstar 4918. C. ANIK 4919. D. Molniya 4920. 4921. 19. What is the orbit of Motorola’s Iridium satellite system? 4922. A. Polar 4923. B. Equatorial 4924. C. Inclined elliptical 4925. D. Inclined equatorial 4926. 4927. 20. What band of frequencies do these satellites operate? 4928. A. L band 4929. B. Ka band 4930. C. C band 4931. D. Ku band 4932. 4933. 4934. 21. Iridium satellites can provide data communications of up ____ bps data rate. 4935. A. 1200 4936. B. 4800 4937. C. 2400 4938. D. 3840 4939. 4940. 22. What satellite system is also known as Navstar? 4941. A. GPS 4942. B. Iridium 4943. C. Globalstar 4944. D. Intelsat 4945. 4946. 23. What is the orbit height of a GPS satellite? 4947. A. 10,898 nmi = 12,541.2 mi = 20,183 km 4948. B. 10,898 mi 4949. C. 10,898 km 4950. D. 10, 898 m 4951. 4952. 24. What is the orbital period of each satellite in the GPS constellation? 4953. A. 6 h 4954. B. 12 h 4955. C. 5 h 4956. D. 15 h 4957. 4958. 25. What term is normally associated with specifying the location of a celestial body in space? 4959. A. Constellation 4960. B. Galaxy 4961. C. Satellite 4962. D. Ephemeris 4963. 4964. 26. What is the angle of inclination of GPS system? 4965. A. 55˚ 4966. B. 65˚ 4967. C. 105˚ 4968. D. 45˚ 4969. 4970. 27. What material is most often used for the outer covering of coaxial cables? 4971. A. PVC 4972. B. Teflon 4973. C. PE 4974. D. Polystyrene 4975. 4976. 4977. 4978. 4979. 4980. 28. What is the dielectric constant of polyethylene (PE) insulator? 4981. A. 2.5 4982. B. 3.3 4983. C. 2.27 4984. D. 2.1 4985. 4986. 29. Polytetrafluoroethylene (PTFE) is also widely used insulator and is known as. 4987. A. polystyrene 4988. B. teflon 4989. C. ceramic 4990. D. bakelite 4991. 4992. 30. What is the characteristic impedance of a two-wire line with the following data: diameter = 0.023in., spacing =0.5 in., insulation = PE.? 4993. A. 300Ω 4994. B. 250Ω 4995. C. 305Ω 4996. D. 301Ω 4997. 4998. 31. What is the characteristic impedance of a coaxial line with the following data: inner diameter = 0.2 in., center conductor diameter = 0.06 in., insulation = Teflon. 4999. A. 200Ω 5000. B. 75Ω 5001. C. 50Ω 5002. D. 150Ω 5003. 5004. 32. A pair of current-carrying conductors is not considered a transmission line unless it is at least ___ λ long at the signal frequency. 5005. A. 0.1 5006. B. 0.3 5007. C. 0.2 5008. D. 0.4 5009. 5010. 33. If the operating frequency is 450 MHz what length of a pair of conductors is considered to be a transmission line? 5011. A. 2.19 ft 5012. B. 2.19 m 5013. C. 0.219 ft 5014. D. 0.219 m 5015. 5016. 34. What is the physical length of the above transmission line at 3/8λ long? 5017. A.0.82 m 5018. B. 0.82 ft 5019. C. 0.82 in 5020. D. 0.82 cm 5021. 5022. 35. Which of the following coaxial cable connectors is called the UHF connector? 5023. A. PL-259 5024. B. BNC 5025. C. N-type connector 5026. D. F connector 5027. 5028. 36. What connector is popular in attaching test instruments like oscilloscopes, frequency counters, spectrum analyzers, etc? 5029. A. UHF connector 5030. B. PL-259 5031. C. BNC 5032. D. SMA 5033. 5034. 37. Which coaxial cable connector is least expensive and is widely used for TV sets,VCRs and cable TV? 5035. A. N-type connector 5036. B. F-type connector 5037. C. BNC 5038. D. PL-259 5039. 5040. 38. Which coaxial connector is a more complex and expensive but do a better job in maintaining the electrical characteristics of the cable through the interconnections? 5041. A. N-type connector 5042. B. F-type connector 5043. C.BNC 5044. D. PL-259 5045. 5046. 39. The velocity factor in transmission lines vary from ___ to ___. 5047. A. 0.6 to 0.8 5048. B. 0.3 to 0.5 5049. C.0.5 to 0.9 5050. D. 0.8 to 0.9 5051. 5052. 40. What is the typical velocity factor of coaxial cables? 5053. A. 0.6 to 0.8 5054. B. 0.3 to 0.5 5055. C. 0.5 to 0.9 5056. D. 0.4 to 0.6 5057. 5058. 41. What is the typical velocity factor of open-wire line? 5059. A. 0.9 5060. B. 0.8 5061. C. 0.5 5062. D. 0.7 5063. 5064. 5065. 42. What line has a typical velocity factor of about 0.8? 5066. A. Shielded pair 5067. B. Flexible coaxial 5068. C. Twin-lead 5069. D. Open-wire line 5070. 5071. 43. What is the velocity factor of coaxial cable with a characteristic impedance of 50Ω and capacitance of 30pF/ft and inductance of 75 nH/ft? 5072. A. 0.58 5073. B.0.68 5074. C. 0.98 5075. D. 0.81 5076. 5077. 44. What is transit time (time delay) of a 50-ft length transmission line of the above problem? 5078. A. 50 ns 5079. B. 100 ns 5080. C. 75 ns 5081. D. 65 ns 5082. 5083. 45. What do you call a transmission line used specifically for the purpose of achieving delay? 5084. A. Delay line 5085. B. Flat line 5086. C. Resonant line 5087. D. Non-resonant line 5088. 5089. 46. What is the time delay introduced by a 75-ft coaxial cable with a dielectric constant of 2.3? 5090. A. 1.54 ns 5091. B. 11.5 ns 5092. C. 115.6 ns 5093. D. 1156 ns 5094. 5095. 47. Assume a frequency of 4 MHz, determine the phase shift offered by the line in the above problem. 5096. A. 108.5˚ 5097. B. 106.5˚ 5098. C. 115.5˚ 5099. D. 166.5˚ 5100. 5101. 48. Find the load impedance that must be used to terminate RG-62A/U to avoid reflections? 5102. A. 93Ω 5103. B. 75Ω 5104. C. 50Ω 5105. D. 300Ω 5106. 5107. 5108. 5109. 49. Find the equivalent inductance per foot of the above cable? 5110. A. 13.5 nF/ft 5111. B. 13.5 pF/ft 5112. C. 116.8 nH/ft 5113. D. 116.8 pF/ft 5114. 5115. 50. An RG-11/U foam coaxial cable has a maximum voltage standing wave of 52 V and a minimum voltage of 17 V. Find the value of the resistive load. 5116. A. 24.59Ω 5117. B. Either A or C 5118. C. 228.75Ω 5119. D. Neither A nor C 5120. 5121. 51. Sound provides all sorts of information. What information is related to mental processes of knowledge, reasoning, memory, judgement and perception? 5122. A. Cognitive 5123. B. Affective 5124. C. Digital 5125. D. Analog 5126. 5127. 52. What sound characteristic relates to a sonic time pattern? 5128. A. Tempo 5129. B. Attack 5130. C. Rhythm 5131. D. Timbre 5132. 5133. 53. What is considered the most obvious conveyor of information? 5134. A. Sound 5135. B. Speech 5136. C. Music 5137. D. Noise 5138. 5139. 54. Attack is a sound characteristic that refers to the way a sound begins. Which of the following is NOT an attack of sound? 5140. A. Hard 5141. B. Soft 5142. C. Crisp 5143. D. Simple 5144. 5145. 55. At what loudness level do pitch (in mels) and frequency (in Hz) are numerically equal? 5146. A. 0 dB 5147. B. 20 dB 5148. C. 60 dB 5149. D. 40 dB 5150. 5151. 5152. 56. The basic voice band has how many octaves? 5153. A. 10 5154. B. 4 5155. C. 5 5156. D. 3 5157. 5158. 57. The ratio of frequencies is termed. 5159. A. interval 5160. B. octave 5161. C. harmonics 5162. D. factor 5163. 5164. 58. What is the tonal ratio of an octave? 5165. A. 1 to 2 5166. B. 1 to 3 5167. C. 2 to 1 5168. D. 3 to 1 5169. 5170. 59. If the loudness level is 100 phons, what is this in sone unit? 5171. A. 100 5172. B. 90 5173. C. 106 5174. D. 96 5175. 5176. 60. What octave bands are there in the midrange? 5177. A. 1st and 2nd 5178. B. 5th, 6th and 7th 5179. C. 3rd and 4th 5180. D. 8th and 9th 5181. 5182. 61. How much louder is 80 phons over 60 phons? 5183. A. 1000 times 5184. B.4 times louder 5185. C. 100 times 5186. D. Twice as loud 5187. 5188. 62. What increase in sound level is commonly perceived by most people? 5189. A. 6 to 10 dB 5190. B. 1 to 3 dB 5191. C. 3 to 6 dB 5192. D. 10 to 20dB 5193. 5194. 5195. 5196. 5197. 5198. 63. What is typical loudness level of an acoustic guitar 1 foot away? 5199. A. 60dB 5200. B. 100dB 5201. C. 80dB 5202. D. 40dB 5203. 5204. 64. What do you call the perceptible sound repetition? 5205. A. Reverberation 5206. B. Echo 5207. C. Reflection 5208. D. Masking 5209. 5210. 65. What is the amount of sound reduction provided by a barrier – wall, floor, or ceiling called? 5211. A. Sound Attenuation 5212. B. Transmission loss 5213. C. Sound absorption 5214. D. Barrier loss 5215. 5216. 66. What is the frequency of a 2-cm sound wave in sea water at 25˚C? 5217. A. 76 kHz 5218. B. 76 Hz 5219. C. 76 MHz 5220. D. 76 mHz 5221. 5222. 67. A choir consisting of 36 individuals all of whom can sing with the same intensity. A soloist sings a certain passage and then is joined by the remainder of the choir members for a repeat of the passage. What is the difference in the sound intensity level in the two cases? 5223. A. 3 dB 5224. B. 6 dB 5225. C. 36 dB 5226. D. 15.6dB 5227. 5228. 68. For the safety and comfort of factory workers, the sound-intensity level in a certain factory must remain below 85 dB. What is the maximum sound intensity allowed in this factory? 5229. A. 3.2 x 10-4 W/m2 5230. B. 3.2 x 10-6 W/m2 5231. C. 3.2 x 10-10 W/m2 5232. D. 3.2 x 10-3 W/m2 5233. 5234. 69. What sound intensity corresponds to a sound-intensity level of 50dB? 5235. A. 1 x 10-6W/m2 5236. B. 1 x 10-7W/m2 5237. C. 1 x 10-8W/m2 5238. D.1 x 10-5W/m2 5239. 5240. 70. The sound intensity received from the nearby jet plane is 12.6 µW/m2 and that from another jet plane some distance away is 0.45 µW/m2. Find the relative loudness of the two. 5241. A. 14.0 dB 5242. B. 14.5dB 5243. C. 12.5 5244. D. 14.5 5245. 5246. 71. The noise from an airplane engine 100 ft from an observer is found to have an intensity of 45dB. What will be the intensity when the plane flies overhead at an altitude of 1 mi? 5247. A. 10.5 dB 5248. B. 34.5 dB 5249. C. 35 dB 5250. D. 20.5 dB 5251. 5252. 72. What is the apparent loudness of 80 dB? 5253. A. Moderate 5254. B. Very loud 5255. C. Loud 5256. D. Deafening 5257. 5258. 73. What loudness level in which permanent damage to hearing is possible? 5259. A. 120 dB 5260. B. 140 dB 5261. C. 130 dB 5262. D. 150 dB 5263. 5264. 74. What is sound pressure level if the RMS sound pressure is 100 μbars? 5265. A. 114 dB 5266. B. 11.4 dB 5267. C. 94 dB 5268. D. 57 dB 5269. 5270. 75. What is the velocity of sound in wood (m/s)? 5271. A. 330 5272. B. 3600 5273. C. 3300 5274. D. 5800 5275. 5276. 76. What is the optimum reverberation time at 500 to 1000 Hz of an auditorium? 5277. A. 0.9 to 1.1 s 5278. B. 1.4 to 1.6 s 5279. C. 1.5 to 1.6 s 5280. D. 1.6 to 1.8 s 5281. 5282. 5283. 5284. 77. For a cinema, the optimum volume per person required is 5285. A. 3.1 5286. B. 2.8 5287. C. 7.1 5288. D. 4.2 5289. 5290. 78. Which of the following is NOT an acoustical defect to be avoided in acoustical designs? 5291. A. Reverberation 5292. B. Flutter echo 5293. C. Distortion 5294. D. Sound concentration 5295. 5296. 79. What absorber in which efficient absorption is only possible over a very narrow band approaching 1.0 (total absorption)? 5297. A. Porous material 5298. B. Helmholtz resonator 5299. C. Panel Absorber 5300. D. Membrane absorber 5301. 5302. 80. How many voice signals (4 kHz max.) would fit into a 5 MHz spectrum? 5303. A. 1250 5304. B. 500 5305. C. 1000 5306. D. 1500 5307. 5308. 81. How many FM stations would be accommodated I an ordinary TV channel? 5309. A. 33 5310. B. 30 5311. C. 40 5312. D. 25 5313. 5314. 82. What is the actual length in feet of a one-quarter wavelength of a coax with a velocity factor of 0.695 at 45 MHz? 5315. A. 17.82 5316. B. 19.26 5317. C. 16.28 5318. D. 16.97 5319. 5320. 83. Determine the terrain sensitivity loss for a 4-GHz carrier that is propagating over a very dry, mountainous area. 5321. A. -1.25 dB 5322. B. -3.05 dB 5323. C. -2.01 dB 5324. D. -5.01 dB 5325. 5326. 5327. 84. A satellite transmitter operates at 4GHz with an antenna gain of 4dBi. The receiver 40000 km away has an antenna gain of 50 dBi. If the transmitter has a power of 8 W, find (ignoring feedline losses and mismatch) the EIRP in dBW. 5328. A. 50 5329. B. 69 5330. C. 49 5331. D. 30 5332. 5333. 85. A radio signal moves from air to glass. The angle of incidence is 20°. Calculate the angle of refraction. The relative permittivity of the glass is 7.8. 5334. A. 7.8° 5335. B. 5.04° 5336. C. 6.04° 5337. D. 7.04° 5338. 5339. 86. At a certain time, the MUF for transmission at an angle of incidence of 75° is 17 MHz. What is the critical frequency? 5340. A. 4.4 MHz 5341. B. 3.5 MHz 5342. C. 6.5 MHz 5343. D. 1.5 MHz 5344. 5345. 87. A properly matched transmission line has a loss of 1.5 dB/100m. if 10 W is supplied to one end of the line, how many watts reach the load, 27 m away? 5346. A. 10 W 5347. B. 7.2 W 5348. C. 9.9 W 5349. D. 9.1 W 5350. 5351. 88. The electromagnetic radiation theory was profounded by 5352. A. Sir Edward Appleton 5353. B. Guglielmo Marconi 5354. C. Heinrich Hertz 5355. D. James C. Maxwell 5356. 5357. 89. What is caused by the transverse nature of electromagnetic waves? 5358. A. Polarization 5359. B. Interference 5360. C. Beamwidth 5361. D. Gain 5362. 5363. 90. Which propagation method is known as special case of skywave? 5364. A. Space wave 5365. B. Troposcatter 5366. C. Ground wave 5367. D. Direct wave 5368. 91. What is the orbit inclination of geostationary satellites? 5369. A. 0° 5370. B. 10° 5371. C. 20° 5372. D. 30° 5373. 5374. 92. A transmission line of unknown impedance is terminated with two different resistances, and an SWR is measured each time. With a 75 Ω termination, the SWR measures 1.5. With a 300 Ω termination, it measures 2.67. What is the impedance of the line? 5375. A. 100 Ω 5376. B. 212 Ω 5377. C. 300 Ω 5378. D. 112 Ω 5379. 5380. 93. What is the high frequency sound that cannot be heard by the human ear? 5381. A. Ultrasonic 5382. B. Transonic 5383. C. Subsonic 5384. D. Supersonic 5385. 5386. 94. What frequency is 10 octaves above 30 Hz? 5387. A. 30.72 kHz 5388. B. 30 kHz 5389. C. 300 Hz 5390. D. 307.2 kHz 5391. 5392. 95. A radio signal travels ____ yards per microseconds. 5393. A. 273 5394. B. 328 5395. C. 618 5396. D. 123.6 5397. 5398. 96. What is the actual length in feet of a one-half wavelength of a coax with a velocity factor of 0.63 at 28 MHz? 5399. A. 44.28 5400. B. 43.46 5401. C. 11.07 5402. D. 46.27 5403. 5404. 97. The range of speech power is ____. 5405. A. 1 – 10 watts 5406. B. 100 – 1000 milliwatts 5407. C. 10 – 100 milliwatts 5408. D. 10 – 1000 microwatts 5409. 5410. 98. What is the actual length in feet of a one-quarter wavelength of a coax with a velocity factor of 0.68 to 30 MHz? 5411. A. 19.26 5412. B. 5.6 5413. C. 17.82 5414. D. 16.97 5415. 5416. 99. What is actual length in feet of a one-half wavelength of a coax with a velocity factor of 0.59 at 26 MHz? 5417. A. 11.16 5418. B. 40.29 5419. C. 42.46 5420. D. 46.28 5421. 5422. 100. The agreed standard for measuring loudness is the loudness sensation produced by a 1000 Hz sine wave _____ dB above the listener’s threshold of hearing. 5423. A. 80 5424. B. 50 5425. C. 30 5426. D. 40 5427. 5428. 5429. 5430. 5431. 5432. 5433. 5434. 5435. 5436. 5437. 5438. 5439. 5440. 5441. 5442. 5443. 5444. 5445. 5446. 5447. 5448. 5449. 5450. 5451. 5452. 5453. Test Yourself – Exam 08 5454. 5455. What is the refractive index of an ionospheric layer with 100x105 free electrons per m3? 5456. Assume frequency to be at 20 MHz. 5457. A. 0.99 5458. B. 0.15 5459. C. 0.78 5460. D. 0.85 5461. 5462. 2. “Each point on a spherical wavefront may be considered a source of secondary spherical wavefronts”. This is known as the 5463. A. Snell’s law 5464. B. D’Alembert’s principle 5465. C. Appleton’s theory 5466. D. Huygen’s principle 5467. 5468. 3. What is meant by the term deviation ratio? 5469. A. The ratio of the audio modulating frequency to the center carrier frequency. 5470. B. The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency. 5471. C. The ratio of the carrier center frequency to the audio modulating frequency. 5472. D. The ratio of the highest audio modulating frequency to the average audio modulating frequency. 5473. 5474. 4. What is the major cause of selective fading? 5475. A. Small changes in the beam heading at the receiving station. 5476. B. Large changes in the height of the ionosphere, as experience at the receiving station. 5477. C. Time differences between the receiving and transmitting stations. 5478. D. Phase differences between radio wave components of the same transmission, as experienced at the receiving station. 5479. 5480. 5. What phenomenon causes the radio-path horizon distance to exceed the geometric horizon? 5481. A. E-layer skip. 5482. B. D-layer skip. 5483. C. Auroral skip. 5484. D. Radio waves may be bent. 5485. 5486. 6. What propagation condition is usually indicated when a VHF signal is received from a station over 500 miles away? 5487. A. D-layer absorption 5488. B. Faraday rotation 5489. C. Tropospheric ducting 5490. D. Moonbounce 5491. 5492. 7. What is meant by the term modulation index? 5493. A. The processor index. 5494. B. The ratio between the deviation of a frequency modulated signal and the modulating frequency. 5495. C. The FM signal-to-noise ratio. 5496. D. The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency. 5497. 5498. 8. The bending of radio waves passing over the top of a mountain range that disperses a weak portion of the signal behind the mountain is 5499. A. eddy-current phase effect 5500. B. knife-edge diffraction 5501. C. shadowing 5502. D. mirror refraction effect 5503. 5504. 9. What is the wavelength of a signal at 500 MHz? 5505. A. 0.062 cm 5506. B. 6 meters 5507. C. 60 cm 5508. D. 60 meters 5509. 5510. 10. What is included in the total resistance of an antenna system? 5511. A. Radiation resistance plus space impedance 5512. B. Radiation resistance plus transmission resistance 5513. C. Transmission line resistance plus radiation resistance 5514. D. Radiation resistance plus ohmic resistance 5515. 11. What are electromagnetic waves? 5516. A. Alternating currents in the core of an electromagnet 5517. B. A wave consisting of two electric fields at right angles to each other 5518. C. A wave consisting of an electric field and a magnetic field at right angles to each other 5519. D. A wave consisting of two magnetic fields at right angles to each other 5520. 5521. 12. The band of frequencies least susceptible to atmospheric noise and interference is: 5522. A. 30 – 300 kHz 5523. B. 300 – 3000 kHz 5524. C. 3 – 30 MHz 5525. D. 300 – 3000 MHz 5526. 5527. 13. What is the relationship in degrees of the electrostatic and electromagnetic fields of an antenna? 5528. A. 0 degree 5529. B. 45 degrees 5530. C. 90 degrees 5531. D. 180 degrees 5532. 5533. 14. For a space wave transmission, the radio horizon distance of a transmitting antenna with a height of 100 meters is approximately: 5534. A. 10 km 5535. B. 40 km 5536. C. 100 km 5537. D. 400 km 5538. 5539. 15. What is meant by referring to electromagnetic waves as horizontally polarized? 5540. A. The electric field is parallel to the earth. 5541. B. The magnetic field is parallel to the earth. 5542. C. Both the electric and magnetic fields are horizontal 5543. D. Both the electric and magnetic fields are vertical 5544. 5545. 16. What is meant by referring to electromagnetic waves as having circular polarization? 5546. A. The electric field is bent into a circular shape. 5547. B. The electric field rotates 5548. C. The electromagnetic wave continues to circle the earth 5549. D. The electromagnetic wave has been generated by a quad antenna 5550. 5551. 17. If a transmitting antenna is 100 meters high and a separate receiving antenna is 64 meters high, what is the maximum space wave communication distance possible between them? 5552. A. 18 km 5553. B. 72 km 5554. C. 164 km 5555. D. 656 km 5556. 5557. 18. A receiver is located 64 km from a space wave transmitting antenna that is 100 meters high. Find the required height of the receiving antenna. 5558. A. 36 meters high 5559. B. 64 meters high 5560. C. 100 meters high 5561. D. 182.25 meters high 5562. 5563. 19. Which of the following is not one of the natural ways a radio wave may travel from transmitter to receiver? 5564. A. Ground wave 5565. B. Micro wave 5566. C. Sky wave 5567. D. Space wave 5568. 5569. 20. Which of the following terrain types permits a ground wave to travel the farthest? 5570. A. Salt water 5571. B. Fresh water 5572. C. Sandy 5573. D. Rocky 5574. 5575. 21. What is the input terminal impedance at the center if a folded dipole antenna? 5576. A. 300 ohms 5577. B. 72 ohms 5578. C. 50 ohms 5579. D. 450 ohms 5580. 5581. 22. What is the term used to describe a spread spectrum communications system where the center frequency if a conventional carrier is altered many time per second in accordance with a pseudo-random list of channels? 5582. A. Frequency hopping 5583. B. Direct sequence 5584. C. Time-domain frequency modulation 5585. D. Frequency compandored spread spectrum 5586. 5587. 23. What is the velocity factor for non-foam dielectric 50 or 75 ohm flexible coaxial cable such as RG 8, 11, 58 and 59? 5588. A. 2.70 5589. B. 0.66 5590. C. 0.30 5591. D. 0.10 5592. 5593. 5594. 5595. 5596. 5597. 24. If a transmission line has a power loss of 6 dB per 100 feet, what is the power at the feed point to the antenna at the end of a 200 foot transmission line fed by a 100 watt transmitter? 5598. A. 70 watts 5599. B. 50 watts 5600. C. 25 watts 5601. D. 6 watts 5602. 5603. 25. What determines the velocity factor in a transmission line? 5604. A. The termination impedance 5605. B. The line length 5606. C. Dielectrics in the line 5607. D. The center conductor resistivity 5608. 5609. 26. What term is used to describe a spread spectrum communications system in which a very fast binary bit stream is used to shift the phase of an RF carrier? 5610. A. Frequency hopping 5611. B. Direct sequence 5612. C. Binary phase-shift keying 5613. D. Phase compandored spread spectrum 5614. 5615. 27. Which of the following frequency bands is best suited for ground wave propagation? 5616. A. 30 to 300 kHz 5617. B. 300 kHz to 3 MHz 5618. C. 3 MHz to 30 MHz 5619. D. 30 MHz to 300 MHz 5620. 5621. 28. Which of the following frequency bands is best suited for sky wave propagation? 5622. A. 30 to 300 kHz 5623. B. 3 MHz to 30 MHz 5624. C. 30 MHz to 300 MHz 5625. D. 3 GHz to 30 GHz 5626. 5627. 29. What is the seventh harmonic of a 100 MHz quarter wavelength antenna? 5628. A. 14.28 MHz 5629. B. 107 MHz 5630. C. 149 MHz 5631. D. 700 MHz 5632. 5633. 30. Which if the following layers of the ionosphere has no effect on sky wave propagation during the hours of darkness? 5634. A. D 5635. B. E 5636. C. F1 5637. D. F2 5638. 5639. 31. Skip distance can be maximized by using the ____ radiation angle possible and the ____ frequency that will be refracted at that angle. 5640. A. lowest, lowest 5641. B. lowest, highest 5642. C. highest, lowest 5643. D. highest, highest 5644. 5645. 32. What is the meaning of the term “velocity factor” of a transmission line? 5646. A. The ratio of the characteristic impedance of the line to the terminating impedance 5647. B. The index of shielding for coaxial cable. 5648. C. The velocity of the wave on the transmission line multiplied by the velocity of light in a vacuum. 5649. D. The velocity of the wave on the transmission line divided by the velocity of light in a vacuum. 5650. 5651. 33. What is the term for the ratio of actual velocity at which a signal travels through a line to the speed of light in a vacuum? 5652. A. Velocity factor 5653. B. Characteristic impedance 5654. C. Surge impedance 5655. D. Standing wave ratio 5656. 5657. 34. Why is the physical length of a coaxial cable transmission line shorter than its electrical length? 5658. A. Skin effect is less pronounced in the coaxial cable 5659. B. RF energy moves slower along the coaxial cable 5660. C. The surge impedance is higher in the parallel feed line 5661. D. The characteristic impedance is higher in the parallel feed line 5662. 5663. 35. What would be the physical length of a tpical coaxial transmission line that is electrically one-quarter wavelength long at 14.1 MHz? 5664. A. 20 meters 5665. B. 3.51 meters 5666. C. 2.33 meters 5667. D. 0.25 meter 5668. 5669. 36. To obtain the most reliable sky wave propagation the ____ should be used. 5670. A. Lowest useable frequency (LUF). 5671. B. Maximum useable frequency (MUF). 5672. C. Optimum useable frequency (OUF). 5673. D. Critical frequency 5674. 5675. 5676. 5677. 5678. 37. What is the deviation ratio for an FM-phone signal having a maximum frequency swing of plus or minus 5 kHz and accepting a maximum modulation rate of 3kHz? 5679. A. 60 5680. B. 0.16 5681. C. 0.6 5682. D. 1.66 5683. 5684. 38. Tropospheric scatter is a method of sky wave propagation for which of the following frequency bands? 5685. A. 300 kHz to 3 MHz 5686. B. 3 MHz to 30 MHz 5687. C. 30 MHz to 300 MHz 5688. D. 300 MHz to 3 GHz 5689. 5690. 39. What is the frequency range of an aircraft’s radio altimeter? 5691. A. 962 MHz to 1213 MHz 5692. B. 329.15 MHz to 335.00 MHz 5693. C. 4250 MHz to 4350 MHz 5694. D. 108.00 MHz to 117.95 MHz 5695. 5696. 40. What type of transmission is radiated from an aircraft’s radio altimeter antenna? 5697. A. An amplitude modulated continuous wave 5698. B. A pulse position modulated UHF signal 5699. C. A differential phase shift keyed UHF signal 5700. D. A frequency modulated continuous wave 5701. 5702. 41. The polarization of a radio wave: 5703. A. Is perpendicular to the electrostatic field of the antenna 5704. B. Is the same direction as the electrostatic field of the antenna. 5705. C. Is the same direction as the magnetic field of the antenna. 5706. D. Is perpendicular to both the electrostatic and magnetic fields of the antenna. 5707. 5708. 42. A coaxial cable has 7dB of reflected power when the input is 5 watts. What is the output of the transmission line? 5709. A. 5 watts 5710. B. 2.5 watts 5711. C. 1.25 watts 5712. D. 1 watt 5713. 5714. 43. When is it useful to refer to an isotropic radiator? 5715. A. When comparing the gains of directional antennas 5716. B. When testing a transmission line for standing wave ratio 5717. C. When (in the northern hemisphere) directing the transmission in a southerly direction 5718. D. When using a dummy load to tune a transmitter 5719. 5720. 44. Most AM broadcasts employ ___ polarization while most FM broadcasts employ ___ polarization of the radio wave. 5721. A. vertical, vertical 5722. B. vertical, horizontal 5723. C. horizontal, vertical 5724. D. horizontal, horizontal 5725. 5726. 45. How does the gain of a parabolic dish type antenna change when the operating frequency is doubled? 5727. A. Gain does not change 5728. B. Gain is multiplied by 0.707 5729. C. Gain increases 6 dB 5730. D. Gain increases 3 dB 5731. 5732. 46. What is the frequency range of an aircraft’s Very High Frequency (VHF) communications? 5733. A. 118.000 MHz to 136.975 MHz (worldwide up to 151.975 MHz) 5734. B. 108.000 MHz to 117.95 MHz 5735. C. 329.15 MHz to 335.00 MHz 5736. D. 2.0000 MHz to 29.999 MHz 5737. 5738. 47. What is a selective fading effect? 5739. A. A fading effect caused by small changes in beam heading at the receiving station. 5740. B. A fading effect caused by phase differences between radio wave components of the same transmission, as experienced at the receiving station. 5741. C. A fading effect caused by large changes in the height of the ionosphere, as experienced at the receiving station 5742. D. A fading effect caused by time differences between the receiving and transmitting stations. 5743. 5744. 48. If the velocity of propagation in a certain medium is 200x106 m/s, what is its refractive index? 5745. A. 1.3 5746. B. 1.5 5747. C. 1.27 5748. D. 0.67 5749. 5750. 49. What is the resultant field strength at the receiving antenna in space wave propagation under case 2? 5751. A. 0 5752. B. ξd 5753. C. 2ξd 5754. D. 3ξd 5755. 5756. 5757. 5758. 5759. 50. The decimetric wave is using what method of propagation? 5760. A. Ground wave 5761. B. Space wave 5762. C. Sky wave 5763. D. Tropospheric wave 5764. 5765. 51. What is the typical frequency used for communicating to submerged submarines? 5766. A. 100 Hz 5767. B. 500 Hz 5768. C. 4 kHz 5769. D. 200 Hz 5770. 5771. 52. Which frequency bands can be refracted during the day by the D layer? 5772. A. VLF 5773. B. MF 5774. C. LF 5775. D. Both VLF and LF 5776. 5777. 53. What height of an ionized layer is determined from the time interval between the transmitted signal and the ionospheric echo at vertical incidence? 5778. A. Virtual height 5779. B. Apparent height 5780. C. Actual height 5781. D. Effective height 5782. 5783. 54. During the night when the F2 layer combines with F1 layer it falls to what approximate height? 5784. A. 250 km 5785. B. 350 km 5786. C. 300 km 5787. D. 400 km 5788. 5789. 55. Which of the following is considered the most frequently used transmission line? 5790. A. Two-wire open line 5791. B. Twin lead 5792. C. Rigid coaxial line 5793. D. Flexible coaxial line 5794. 5795. 56. The antenna effective height is ____ to ____ of the actual height. 5796. A. ½ to 2/3 5797. B. ½ to ¾ 5798. C. ¼ to 2/3 5799. D. ¼ to ¾ 5800. 5801. 5802. 57. What is the propagation velocity of a signal in a transmission line whose inductance and capacitance are 5μH/m and 20μF/m respectively? 5803. A. 100x103 m/s 5804. B. 100 m/s 5805. C. 10x103 m/s 5806. D. 100x106 m/s 5807. 5808. 58. What is the phase coefficient in radians per unit length of a transmission line at the frequency of 10 MHz if the velocity of propagation is 2.5x108 m/s? 5809. A. 0.25 5810. B. 2.5 5811. C. 0.35 5812. D. 3.5 5813. 5814. 59. Determine the conductance of a two-wire open line with the following parameters: D = 4 in., d = 0.1 in. and ρ = 2.6x108 Ω-m. 5815. A. 2.76x10-9 S/m 5816. B. 2.76x10-6 S/m 5817. C. 2.76x10-12 S/m 5818. D. 2.76x10-3 S/m 5819. 5820. 60. What is the input impedance of a transmission line if its characteristic impedance is 300 Ω and the load is 600 Ω? Assume a quarter wavelength section only. 5821. A. 150 kΩ 5822. B. 150 mΩ 5823. C. 150 Ω 5824. D. 2 Ω 5825. 5826. 61. Determine the standing wave ratio of a 300-Ω line whose load is 400+j150 Ω. 5827. A. 3.55 5828. B. 1.67 5829. C. 5.53 5830. D. 3.35 5831. 5832. 62. What is the optimum volume per person of rooms for speech? 5833. A. 2.8 5834. B. 3.1 5835. C. 4.2 5836. D. 5.1 5837. 5838. 63. What happens to the beamwidth of an antenna as the gain is increased? 5839. A. The beamwidth increases geometrically as the gain is increased. 5840. B. The beamwidth increases arithmetically as the gain is increased. 5841. C. The beamwidth is essentially unaffected by the gain of the antenna. 5842. D. The beamwidth decreases as the gain is increased. 5843. 5844. 64. A superhet receiver has an IF of 455 kHz and is experiencing image-channel interference on a frequency of 1570 kHz. The receiver is tuned to 5845. A. 1115 kHz 5846. B. 660 kHz 5847. C. 2025 kHz 5848. D. 910 kHz 5849. 5850. 65. What is the end impedance of a half-wave dipole? 5851. A. 73 Ω 5852. B. 72 Ω 5853. C. 250 Ω 5854. D. 2500 Ω 5855. 5856. 66. What volume of the chamber is required to measure absorption coefficient at 100 Hz? 5857. A. 125 m3 5858. B. 50 m3 5859. C. 150 m3 5860. D. 352 m3 5861. 5862. 67. What is the optimum reverberation time at 500 Hz for a cinema? 5863. A. 0.8 – 1.2 sec. 5864. B. 0.9 – 1.3 sec. 5865. C. 0.6 – 0.8 sec. 5866. D. 0.45 – 0.55 sec. 5867. 5868. 68. An FM receiver whose intermediate frequency is 10.7 MHz, is experiencing image channel interference from a station transmitting on 121.1 MHz. If the local oscillator is tracking above, the receiver is tuned to 5869. A. 131.8 MHz 5870. B. 110.4 MHz 5871. C. 142.5 MHz 5872. D. 99.7 MHz 5873. 5874. 69. A 1 Mhz carrier is amplitude modulated by a pure 200-Hz audio test tone. Which of the following combinations of frequencies represent the total content of the AM signal? 5875. A. 1 MHz and 200 Hz 5876. B. 1 MHz and 1000.2 kHz 5877. C. 999.8 kHz, 1000 kHz, and 1000.2 kHz 5878. D. 999.8 kHz and 1000.2 kHz 5879. 5880. 70. What establishes the receiver bandwidth? 5881. A. RF amplifier 5882. B. Mixer 5883. C. Local oscillator 5884. D. IF amplifier 5885. 5886. 71. What noise type is observable between 8 MHz to somewhat above 1.43 GHz or up to 1.5 GHz? 5887. A. Solar noise 5888. B. Space noise 5889. C. Galactic noise 5890. D. Cosmic noise 5891. 5892. 72. Flicker noise is a poorly understood form of noise which may be completely ignored about above ____. 5893. A.100 Hz 5894. B. 200 Hz 5895. C. 400 Hz 5896. D. 500 Hz 5897. 5898. 73. What is the typical gain of a rhombic antenna? 5899. A. Between 15 to 60 5900. B. Between 20 to 90 5901. C. Between 50 to 75 5902. D. Between 10 to 25 5903. 5904. 74. What illumination factor is normally considered in computing parabolic antenna gain in microwave communications? 5905. A. 0.54 5906. B. 0.65 5907. C. 0.75 5908. D. 0.85 5909. 5910. 75. How many voice band channels are there in a superjumbo group? 5911. A. 600 5912. B. 900 5913. C. 10,800 5914. D. 3,600 5915. 5916. 76. In acoustics, what is the reference pressure in lb/ft2 unit? 5917. A. 2x10-5 5918. B. 0.0002 5919. C. 2.089 5920. D. 2.980 5921. 5922. 77. Which of the following characterizes a properly terminated transmission line? 5923. A. The line loss is minimum. 5924. B. The standing wave ratio is minimum. 5925. C. The input impedance is twice the load impedance. 5926. D. The standing wave ratio is one. 5927. 5928. 5929. 78. What is the meaning of forward power? 5930. A. The power traveling from the transmitter to the antenna. 5931. B. The power radiated from the top of an antenna system. 5932. C. The power produced during the positive half of an RF cycle. 5933. D. The power used to drive a linear amplifier. 5934. 5935. 79. What organization has published safety guidelines for the maximum limits of RF energy near the human body? 5936. A. The American National Standards Institute (ANSI). 5937. B. The Environmental Protection Agency (EPA). 5938. C. The Federal Communications Commission (FCC). 5939. D. The Institute Of Electrical and Electronics Engineers (IEEE). 5940. 5941. 80. When no signal is being received, the loudspeaker is not entirely silent as a result of the presence of 5942. A. parasitic oscillations in some of the receiver stages. 5943. B. negative feedback in each stage. 5944. C. spurious frequencies as a result of improper neutralization. 5945. D. internal receiver noise. 5946. 5947. 81. When measuring a transmitter’s frequency against a suitable standard, the frequency to be measured is taken from the 5948. A. oscillator stage 5949. B. intermediate amplifier 5950. C. buffer stage 5951. D. final RF stage 5952. 5953. 82. When the is the ionosphere most ionized? 5954. A. Dusk 5955. B. Midnight 5956. C. Dawn 5957. D. Midday 5958. 5959. 83. Cellular radios use FM with a maximum deviation of 5960. A. ±30 kHz 5961. B. ±75 kHz 5962. C. ±25 kHz 5963. D. ±12kHz 5964. 5965. 84. What device measures the angle between two radio frequencies and also the direction of propagation of a wave? 5966. A. Densimeter 5967. B. Absorption wavemeter 5968. C. Goniometer 5969. D. Ergometer 5970. 5971. 85. An automated ship-to-shore distress alerting system using satellites and advanced terrestrial communications systems. 5972. A. GPS 5973. B. Iridium system 5974. C. INMARSAT 5975. D. GMDSS 5976. 5977. 86. What antenna can be used to minimize the effect of Faraday rotation of polarization? 5978. A. Dipole 5979. B. Parabolic 5980. C. Helical 5981. D. Rhombic 5982. 5983. 87. The presence of standing waves on a transmission line is the result of 5984. A. a high level of attenuation on the line. 5985. B. terminating the line by a resistive load equal in value to the surge impedance 5986. C. reducing the input power to below its critical level. 5987. D. an impedance mismatch between the load and the line. 5988. 5989. 88. What device measures rf power by measuring the heat the rf power generates? 5990. A. Calorimeter 5991. B. Goniometer 5992. C. Spectrum meter 5993. D. Oscilloscope 5994. 5995. 89. What is considered the most efficient mode in terms of energy transfer in waveguides? 5996. A. Dominant mode 5997. B. Normal mode 5998. C. Conventional mode 5999. D. Vertical mode 6000. 6001. 90. In acoustics, _____ is the apparent change in frequency or pitch when a sound source moves either toward or away from a listener. 6002. A. flanking 6003. B. reverberation 6004. C. Doppler effect 6005. D. echo 6006. 6007. 91. Which of the following wavelengths where absorption of electromagnetic waves becomes peak due to vibrational resonances in the water vapor molecule? 6008. A. 1.35 cm and 1.7 mm 6009. B. 1.5 mm and 5mm 6010. C. 1.35 dm and 1.7cm 6011. D. 1.5 cm and 5 mm 6012. 6013. 6014. 92. Oxygen molecule absorption peaks to electromagnetic wave are at what wavelengths? 6015. A. 1.35 mm and 1.7 μm 6016. B. 1.35 cm and 1.7 mm 6017. C. 5 cm and 2.5 cm 6018. D. 5 mm and 2.5 mm 6019. 6020. 93. The approximate single-hop nighttime range of F2 layer is ____. 6021. A. 3000 km 6022. B. 3840 km 6023. C. 4130 km 6024. D. 2350km 6025. 6026. 94. What ionospheric layer has a daytime approximate critical frequency of 8 MHz? 6027. A. F2 layer 6028. B. F1 layer 6029. C. E layer 6030. D. D layer 6031. 6032. 95. In cellular system, _____ defines the geographic distance that is required between cells using identical frequencies in order to avoid interference between the radio transmissions at these cells. 6033. A. frequency-reuse ratio 6034. B. distance-to-reuse ratio (D/R) 6035. C. reuse format plan ratio 6036. D. reuse factor 6037. 6038. 96. What do you call the ability of a mobile phone to change from one channel (frequency) to another? 6039. A. Frequency agility 6040. B. Frequency handoff 6041. C. Frequency handover 6042. D. Frequency switch 6043. 6044. 97. What mathematical plane figure is ideal in cellular system design and engineering it graphically and functionally depicts overlapping radio coverage between and among adjacent cell base stations? 6045. A. Hexagon 6046. B. Octagon 6047. C. Pentagon 6048. D. Nonagon 6049. 6050. 98. In cellular system, the average lead time to install a new base station is approximately ____ months to a year. 6051. A. 4 6052. B. 5 6053. C. 6 6054. D. 10 6055. 99. What is considered the threshold of audibility at 3000 Hz? 6056. A. 10-12 W/m2 6057. B. 10-16 W/m2 6058. C. 10-12 W/cm2 6059. D. 10-15 W/cm2 6060. 6061. 100. At one atmospheric pressure, what is the approximate speed of sound in steel? 6062. A. 5150 m/s 6063. B. 5150 ft/s 6064. C. 4990 m/s 6065. D. 4990 ft/s 6066. 6067. 6068. 6069. 6070. 6071. 6072. 6073. 6074. 6075. 6076. 6077. 6078. 6079. 6080. Test Yourself – Exam 09 6081. 6082. 1. What significant element of sound refers to its characteristic tonal quality? 6083. A. Pitch 6084. B. Tempo 6085. C. Rhythm 6086. D. Timbre 6087. 6088. 2. What is the velocity of sound in wood? 6089. A. 5800 m/s 6090. B. 5000 m/s 6091. C. 3300 m/s 6092. D. 3700 m/s 6093. 6094. 3. What is the typical loudness level of a watch ticking? 6095. A. 0 phon 6096. B. 40 phons 6097. C. 20 phons 6098. D. 60 phons 6099. 6100. 4. The typical length of the rhombic antenna is ____. 6101. A. 2λ to 8λ 6102. B. 10λ to 20λ 6103. C. 1λ to 3λ 6104. D. 5λ to 10λ 6105. 6106. 5. What is the carrier frequency of supergroup 10? 6107. A. 2724 kHz 6108. B. 2356 kHz 6109. C. 2108 kHz 6110. D. 3100 kHz 6111. 6112. 6113. 6. In SPADE system, how many PCM-encoded voice band channels are there? 6114. A. 800 6115. B. 600 6116. C. 300 6117. D. 240 6118. 6119. 7. The product of the radiated RF power of a transmitter and the gain of the antenna system in a given direction relative to an isotropic radiator is called ____. 6120. A. Effective Radiated Power (ERP) 6121. B. Effective Isotropic Radiated Power (EIRP) 6122. C. Radiated Power 6123. D. Transmit Power 6124. 6125. 8. The product of antenna input power and the antenna power gain expressed in kW is called __. 6126. A. Effective Radiated Power (ERP) 6127. B. Effective Isotropic Radiated Power (EIRP) 6128. C. Radiated Power 6129. D. Transmit Power 6130. 6131. 9. What satellite system parameter represents the quality of a satellite or an earth station receiver? 6132. A. Gain-to-Equivalent Noise Temperature Ratio (G/Te) 6133. B. Energy of Bit-to-Noise Density Ratio (Eb/No) 6134. C. Carrier-to-Noise Density Ratio (C/No) 6135. D. Bit energy 6136. 6137. 10. What noise is observable at frequencies in the range from about 8 MHz to somewhat 1.5 GHz? 6138. A. Industrial noise 6139. B. Atmospheric noise 6140. C. Space noise 6141. D. Shot noise 6142. 6143. 11. A special horn antenna consisting of a parabolic cylinder joined to a pyramidal horn. 6144. A. Hoghorn 6145. B. Cass-horn 6146. C. Pyramidal horn 6147. D. Conical horn 6148. 6149. 12. How many telegraph channels are there in the basic voice band channels? 6150. A. 24 6151. B. 96 6152. C. 48 6153. D. 672 6154. 6155. 6156. 13. Which of the following is oldest multiplexing scheme? 6157. A. Frequency Division Multiplexing (FDM) 6158. B. Time Division Multiplexing (TDM) 6159. C. Code Division Multiplexing (CDM) 6160. D. Space Division Multiplexing (SDM) 6161. 6162. 14. What carrier system multiplexes 96 voice band channels into a single 6.312 Mbps data signal? 6163. A. T1 carrier system 6164. B. T2 carrier system 6165. C. T1C carrier system 6166. D. T3 carrier system 6167. 6168. 15. What is the metric subdivision of VHF band? 6169. A. Metric 6170. B. Millimetric 6171. C. Decimetric 6172. D. Centimetric 6173. 6174. 16. In satellite communications, what means of attitude control is using the angular momentum of the spinning body to provide the roll and yaw stabilization? 6175. A. Spin stabilization 6176. B. Radial stabilization 6177. C. Three-axis stabilization 6178. D. Station keeping 6179. 6180. 17. Which of the following is NOT a porous absorber? 6181. A. Prefabricated tiles 6182. B. Plasters and spray on materials 6183. C. Acoustic blankets 6184. D. Membrane absorber 6185. 6186. 18. What historical satellite broadcasted live the 1964 Olympic games from Tokyo, Japan for the first time? 6187. A. Syncom I 6188. B. Syncom III 6189. C. Syncom II 6190. D. Syncom IV 6191. 6192. 19. In transmission line, which of the following is the first step in the procedure of using stub matching? 6193. A. Calculate stub susceptance. 6194. B. Calculate load admittance 6195. C. Connect stub to load 6196. D. Transform conductance to resistance 6197. 6198. 20. What type of balun (balanced-to-unbalanced) is used in high frequency applications? 6199. A. Transformer type balun 6200. B. A specially configured coaxial transmission line 6201. C. A specially configured parallel-wire line 6202. D. A λ/2 transformer balun 6203. 6204. 21. ____ is defined as any radiation of energy by means of electromagnetic wave. 6205. A. Emission 6206. B. Radiation 6207. C. Radio 6208. D. Broadcasting 6209. 6210. 22. In what year did Hertz discover radio waves? 6211. A. 1844 6212. B. 1873 6213. C. 1887 6214. D. 1895 6215. 6216. 23. Which of the following phenomena is possible is free space medium? 6217. A. Reflection of radio wave 6218. B. Diffraction of radio wave 6219. C. Refraction of radio wave 6220. D. Attenuation of radio wave 6221. 6222. 24. What is the reactance property at the input of a shorted quarter wavelength line? 6223. A. A parallel LC circuit 6224. B. A pure inductive reactance 6225. C. A series LC circuit 6226. D. A pure capacitive reactance 6227. 6228. 25. An early satellite owned by US Department of Defense that lasted only for 17 days 6229. A. Courier 6230. B. Echo 6231. C. Score 6232. D. Westar 1 6233. 6234. 26. Which of the following is the consolidation of H. No. 5224 and S. No. 2683? 6235. A. RA 9292 6236. B. RA 5734 6237. C. RA 7925 6238. D. RA 6849 6239. 6240. 6241. 6242. 6243. 6244. 27. Who will appoint the chairman and 2 members of the board of Electronics Engineering? 6245. A. The Senate President 6246. B. The President 6247. C. The Supreme Court 6248. D. The Commission on Appointment 6249. 6250. 28. How many nominees per position of the Electronics Engineering Board are nominated by IECEP to PRC? 6251. A. 3 6252. B. 5 6253. C. 4 6254. D. 6 6255. 6256. 29. According to RA 9292, how many days after the board exam the results will be released? 6257. A. Within 5 days 6258. B. Within 15 days 6259. C. Within 20 days 6260. D. Within 3 days 6261. 6262. 30. How many removal examination (s) will be given to an examinee who obtains a passing rating in the majority of the subjects but obtains a rating in the other subject (s) below seventy percent (70%) but not lower than sixty percent (60%)? 6263. A. 1 6264. B. 3 6265. C. 2 6266. D. Unlimited 6267. 6268. 31. Which of the following determines the acoustic behavior of gases? 6269. A. Density 6270. B. Pressure 6271. C. Temperature 6272. D. All of the choices 6273. 6274. 32. In what medium sound travels the faster? 6275. A. Vacuum 6276. B. Solid 6277. C. Liquid 6278. D. Gas 6279. 6280. 33. For a loudness level between 110 and 120 dB, the maximum daily exposure limit is ____ minute (s). 6281. A. 1 6282. B. 60 6283. C. 20 6284. D. 45 6285. 6286. 34. A porous material is far more efficient at high than low frequency absorption. How to improve sound absorption at lower frequencies using this absorber? 6287. A. Increase the thickness 6288. B. Decrease the thickness 6289. C. Mount with and airspace behind 6290. D. Both A and C above 6291. 6292. 35. Which of the following describes a TDM frame? 6293. A. A 250-μs frame 6294. B. A 125-μs frame 6295. C. A 500-μs frame 6296. D. A 60-μs frame 6297. 6298. 36. ____ system transmits frequency-division-multiplexed voice band signals over a coaxial cable for distances up to 4000 miles. 6299. A. T carrier 6300. B. X carrier 6301. C. L carrier 6302. D. F carrier 6303. 6304. 37. What is the spectrum range of U600 mastergroup? 6305. A. 60 – 108 kHz 6306. B. 564 – 3084 kHz 6307. C. 312 – 552 kHz 6308. D. 60 -2788 kHz 6309. 6310. 38. Which frequency reuse method is less effective because of Faraday’s effect? 6311. A. Dual polarization 6312. B. Reducing antenna beamwidth 6313. C. Zonal rotation 6314. D. Spin stabilization 6315. 6316. 39. Three telephone circuits, each having an S/N ratio of 44 dB, are connected in tandem. What is the overall S/N ratio? 6317. A. 44 dB 6318. B. 39.2 dB 6319. C. 41 dB 6320. D. 43.52 dB 6321. 6322. 40. What is the noise factor if the equivalent noise temperature is 25 K? 6323. A. 1.09 6324. B. 0.09 6325. C. 0.36 dBm 6326. D. 0.36 6327. 6328. 6329. 41. A ground station is operating to a geostationary satellite at a 5° angle of elevation. Calculate the round-trip time between ground station and satellite. 6330. A. 275 s 6331. B. 275 ms 6332. C. 137.5 s 6333. D. 137.5 ms 6334. 6335. 42. Calculate the reverberation time of a living room 8 ft high, 13 ft wide and 20 ft long. The total absorption of the building structure inside the room is 180.7 sabines with four persons present in the room. 6336. A. 0.5 ms 6337. B. 0.05 s 6338. C. 0.5 s 6339. D. 5 ms 6340. 6341. 43. What is the number of levels required in a PCM system with S/N ratio of 40 dB? 6342. A. 64 6343. B. 128 6344. C. 256 6345. D. 512 6346. 6347. 44. A radio communications link is to be established via the ionosphere. The maximum virtual height of the layer is 100 km at the midpoint of the path and the critical frequency is 2 MHz. The distance between stations is 600 km. determine the optimum working frequency? 6348. A. 6.32 MHz 6349. B. 2.1 MHz 6350. C. 5.4 MHz 6351. D. 1.8 MHz 6352. 6353. 45. Part of a microwave link can be approximated by free space conditions. The antenna gain are each 40 dB, the frequency is 10 GHz, and the path length is 80 km. Calculate the receive power for a transmitted power of 10 W? 6354. A. 0.871 μW 6355. B. 871 μW 6356. C. 0.871 mW 6357. D. 871 nW 6358. 6359. 46. What is the approximate critical frequency of the E layer? 6360. A. 4 MHz 6361. B. 5 MHz 6362. C. 6 MHz 6363. D. 3 MHz 6364. 6365. 6366. 6367. 6368. 47. What is the approximate single-hop nighttime range of F2 layer? 6369. A. 3840 km 6370. B. 3000 km 6371. C. 4130 km 6372. D. 2350 km 6373. 6374. 48. What ionospheric layer has a daytime approximate critical frequency of 8 MHz? 6375. A. F2 layer 6376. B. F1 layer 6377. C. E layer 6378. D. D layer 6379. 6380. 49. Determine the additional absorption (sabines) contributed by 10 persons in a room. 6381. A. 47 6382. B. 4.7 6383. C. 0.47 6384. D. 470 6385. 6386. 50. A frequency of 3000 Hz has how many octaves above 1000 Hz? 6387. A. 1.6 octaves 6388. B. 2.1 octaves 6389. C. 1 octave 6390. D. 3 octaves 6391. 6392. 51. The loudness level increased from 40 to 56 phons. What is the increase in loudness sensation? 6393. A. 3 times 6394. B. 4.5 times 6395. C. 2 times 6396. D. 4 times 6397. 6398. 52. In the North American TDM system, what is the transmission rate in Mbps of T3 carrier system? 6399. A. 44.736 6400. B. 6.312 6401. C. 3.152 6402. D. 274.176 6403. 6404. 53. What is the data rate in Mbps of a single satellite transponder considering an S/N of 30 dB? 6405. A. 35.8 6406. B. 3.58 6407. C. 358 6408. D. 3580 6409. 6410. 6411. 54. What condition occur when the refractive index of the air decreases with height much more rapidly the normal? 6412. A. Refraction 6413. B. Superrefraction 6414. C. Subrefraction 6415. D. Diffraction 6416. 6417. 55. What do you call the increase of temperature with height? 6418. A. Temperature inversion 6419. B. Normal inversion 6420. C. Ducting 6421. D. Superrefraction 6422. 6423. 56. ____ is a term given to the region where superrefraction occurs. 6424. A. Strata 6425. B. Duct 6426. C. Isothermal region 6427. D. Tropospheric region 6428. 6429. 57. Which of the following wavelengths where absorption of electromagnetic waves becomes peak due to vibrational resonances in the water vapor molecule? 6430. A. 1.35 cm and 1.7 mm 6431. B. 1.5 mm and 5 mm 6432. C. 1.35 dm and 1.7 cm 6433. D. 1.5 cm and 5mm 6434. 6435. 58. Oxygen molecule absorption peaks to electromagnetic wave are at what wavelengths? 6436. A. 1.35 cm and 1.7 mm 6437. B. 5 mm and 2.5 mm 6438. C. 5 cm and 2.5 cm 6439. D. 1.35 mm and 1.7 μm 6440. 6441. 59. What instrument normally measures the virtual height of ionosphere? 6442. A. Ionosonde 6443. B. Altimeter 6444. C. Field meter 6445. D. Radar 6446. 6447. 60. The angle of elevation of the antenna beam is 20°. Calculate the transmission- path distance for an ionospheric transmission that utilizes a layer of virtual height 200 km. Use flat-earth approximation. 6448. A. 966 km 6449. B. 2100 km 6450. C. 1100 km 6451. D. 405 km 6452. 6453. 61. If temperature change is 19°C, what amount of change to sound velocity is possible? 6454. A. 11.53 ft/s 6455. B. 11.53 m/s 6456. C. 19.304 ft/s 6457. D. 19.304 m/s 6458. 6459. 62. In the above problem, what is the new velocity of sound assuming dry air medium? 6460. A. 343 ft/s 6461. B. 3430 m/s 6462. C. 343 m/s 6463. D. 342 m/s 6464. 6465. 63. In acoustics, if the volume of the room is 200 m3 then at what frequency the coefficient of absorption is measured? 6466. A. 120 kHz 6467. B. 120 Hz 6468. C. 100 Hz 6469. D. 150 Hz 6470. 6471. 64. What is the approximate bandwidth of an FM system with 10 kHz of modulating frequency and a 150 kHz of frequency deviation? 6472. A. 300 kHz 6473. B. 320 kHz 6474. C. 150 kHz 6475. D. 200 kHz 6476. 6477. 65. Which of the following layers of the ionosphere has no effect on sky wave propagation during daytime? 6478. A. D 6479. B. E 6480. C. F1 6481. D. F2 6482. 6483. 66. What phenomenon causes the radio-path horizon distance to exceed the geometric horizon? 6484. A. Diffraction 6485. B. Ducting 6486. C. Reflection 6487. D. Refraction 6488. 6489. 67. How to maximize the skip distance? 6490. A. Using the smallest possible radiation angle and highest possible frequency 6491. B. Using the smallest possible radiation angle and lowest possible frequency 6492. C. Using the biggest possible radiation angle and highest possible frequency 6493. D. Using the biggest possible radiation angle and lowest possible frequency 6494. 6495. 68. For a space wave transmission, the radio horizon distance of a receiving antenna with a height of 64 meters is approximately 6496. A. 8 km 6497. B. 32 km 6498. C. 64 km 6499. D. 256 km 6500. 6501. 69. What bandwidth is needed to support a capacity of 128 kbps when the signal power to noise power ratio in decibels is 100? 6502. A. 19224 Hz 6503. B. 3853 Hz 6504. C. 19244 Hz 6505. D. 3583 Hz 6506. 6507. 70. Which of the following systems uses frequency band 870-885 MHz as a transmit band of its base station? 6508. A. TACS 6509. B. NTT 6510. C. NMT 6511. D. AMPS 6512. 6513. 71. A transmitted signal 5 meters in wavelength is received by an antenna coil having a 50-Ω resistance and a 0.01 H inductance. What is the capacitance of the tuner shunting the antenna coil at this point? 6514. A. 0.704 fF 6515. B. 0.704 μF 6516. C. 0.704 nF 6517. D. 0.704 mF 6518. 6519. 72. Which of the following is the basic component of a communications satellite receiver? 6520. A. On-board computer 6521. B. Reflector 6522. C. Telemetry 6523. D. Transponder 6524. 6525. 73. The reverberation time of a 184.2 cubic meters broadcast studio is 0.84 sec. Find the absorption effect of the materials used in metric sabines. 6526. A. 35.3 6527. B. 10.96 6528. C. 379.8 6529. D. 109.6 6530. 6531. 6532. 6533. 6534. 6535. 74. What is the highest frequency that can be sent straight upward and be returned to earth? 6536. A. MUF 6537. B. Gyro frequency 6538. C. Skip frequency 6539. D. Critical frequency 6540. 6541. 75. What is the most important specification of loudspeakers and microphones? 6542. A. Frequency response 6543. B. Power density 6544. C. Field Strength 6545. D. Gain 6546. 6547. 76. Atmospheric attenuation is an attenuation which is due to 6548. A. mist and fog 6549. B. gasses in the atmosphere 6550. C. water vapor and oxygen 6551. D. rain 6552. 6553. 77. Satellite orbits around the earth are ____ orbits. 6554. A. circular 6555. B. either elliptical or circular 6556. C. elliptical 6557. D. circular only 6558. 6559. 78. How does spatial isolation technique in satellite communications avoid interference? 6560. A. Use of different polarity antennas 6561. B. Use of different types of antennas 6562. C. Employment of highly directional spot-beam antennas 6563. D. Use of low gain antennas 6564. 6565. 79. An area on earth covered by a satellite radio beam is called ____. 6566. A. SSP 6567. B. Region 6568. C. footprint 6569. D. primary area 6570. 6571. 80. The American concert pitch A is equivalent to which if the following frequencies? 6572. A. 440 Hz 6573. B. 435 Hz 6574. C. 260 Hz 6575. D. 255 Hz 6576. 6577. 6578. 6579. 6580. 6581. 81. The international pitch A is equivalent to ___ Hz. 6582. A. 435 6583. B. 440 6584. C. 260 6585. D. 255 6586. 6587. 82. The speed of the satellite increases as its height in orbit gets 6588. A. lower 6589. B. higher 6590. C. closer to the moon 6591. D. closer to the sun 6592. 6593. 83. What is the effective radiated power of a repeater with 50 watts transmitter power output \, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 6 dB antenna gain? 6594. A. 158 W 6595. B. 39.7 W 6596. C. 251 W 6597. D. 69.9 W 6598. 6599. 84. A cellular standard known as the cdmaOne. 6600. A. IS-95 6601. B. IS-136 6602. C. IS-54 6603. D. IS-100 6604. 6605. 85. What is the effective radiated power of a repeater with 50 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 7 dB antenna gain? 6606. A. 300 W 6607. B. 315 W 6608. C. 31.5 W 6609. D. 69.9 W 6610. 6611. 86. Which Ethernet system is restricted only to 100 m? 6612. A. 10 Base T 6613. B. 20 Base 2 6614. C. 10 Base 5 6615. D. 10 Base 1 6616. 6617. 87. What is the effective radiated power of a repeater with 75 watts transmitter power output, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 10 dB antenna gain? 6618. A. 600 W 6619. B. 75 W 6620. C. 18.75 W 6621. D. 150 W 6622. 6623. 88. Which of the following regulates the ownership and operation of radio and television stations in the country? 6624. A. PD 576-A 6625. B. PD 756 6626. C. PD 657 6627. D. PD 677 6628. 6629. 89. What is the effective radiated power of a repeater with 75 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 6 dB antenna gain? 6630. A. 37.6 W 6631. B. 237 W 6632. C. 150 W 6633. D. 23.7 W 6634. 6635. 90. In GSM cellular system, the speech coding rate is ____. 6636. A. 13 kbps 6637. B. 8 kbps 6638. C. 15 kbps 6639. D. 20 kbps 6640. 6641. 91. What is the effective radiated power of a repeater with 100 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 10 dB antenna gain? 6642. A. 800 W 6643. B. 126 W 6644. C. 12.5 W 6645. D. 1260 W 6646. 6647. 92. Which NTC memorandum circular governs the rules and regulations about the manufacture, acquisition, sale and service of radio communication equipment? 6648. A. MC No. 2-05-88 6649. B. MC No. 2-04-88 6650. C. MC No. 2-07-88 6651. D. MC No. 2-09-88 6652. 6653. 93. What is the effective radiated power of a repeater with 120 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 6 dB antenna gain? 6654. A. 601 W 6655. B. 240 W 6656. C. 60 W 6657. D. 379 W 6658. 6659. 94. What do you call a short bit sequence sent typically 128 bits in digital signatures? 6660. A. Hash 6661. B. Public key 6662. C. Private key 6663. D. Password 6664. 95. What medium is used by IBM token ring network that operates at either 4 Mbps or 16 Mbps? 6665. A. Twisted pair 6666. B. Coaxial cable 6667. C. Fiber-optic 6668. D. Parallel-wire line 6669. 6670. 96. What is known as the final stage in the evolution of the GSM standard? 6671. A. WAP 6672. B. GPRS 6673. C. EDGE 6674. D. Bluetooth 6675. 6676. 97. According to KBP revised radio code which airtime below is classified class D for AM stations? 6677. A. 6:00 AM to 12:00 NN 6678. B. 12:00 NN to 6:00 PM 6679. C. 9:00 PM to 12 Midnight 6680. D. 12:00 Midnight to 5:00 AM 6681. 6682. 98. Encryption of data is important to ensure its privacy. It is most commonly achieved by using a ____. 6683. A. public-key encryption 6684. B. private-key encryption 6685. C. password-key encryption 6686. D. character set encryption 6687. 6688. 99. The speech coding rate in D-AMPS is ____. 6689. A. 8 kbps 6690. B. 13 kbps 6691. C. 15 kbps 6692. D. 20 kbps 6693. 6694. 100. Which of the following principal musical intervals is considered dissonant? 6695. A. 7:8 6696. B. 1:2 6697. C. 5:8 6698. D. 3:5 6699. 6700. 6701. 6702. 6703. 6704. 6705. 6706. 6707. 6708. 6709. 6710. 6711. 6712. 6713. Test Yourself – Exam 10 6714. ______is a standard whereby mobile phones can gain access to specially tailored Internet websites. 6715. Bluetooth 6716. GPRS 6717. WAP 6718. EDGE 6719. 6720. What noise is a transient short-duration disturbance distributed essentially uniformly over the useful passband of a transmission system? 6721. Flicker noise 6722. Transit-time noise 6723. Shot noise 6724. Impulse noise 6725. 6726. What is the insertion loss of connector type splices for a single mode optical fiber? 6727. 0.51 dB 6728. 0.49 dB 6729. 0.31 dB 6730. 0.38 db 6731. 6732. In the European standard, the aurial transmitter maximum radiated power is ______of peak visual transmitter power. 6733. 10% 6734. 30% 6735. 20% 6736. 40% 6737. 6738. What is the common up-converter and down-converter IF for microwave communications? 6739. 60 MHz 6740. 80 MHz 6741. 120 MHz 6742. 70 MHz 6743. 6744. What is the data link protocol that is used in asynchronous transmission for transferring files from one computer to another? 6745. A modem 6746. X modem 6747. B modem 6748. C modem 6749. 6750. What distortion is not caused by transmission line characteristics? 6751. Phase distortion 6752. Pulse shape distortion 6753. Spacing bias distortion 6754. Amplitude distortion 6755. 6756. What is the effective radiated power of a repeater with 200 watts transmitter power output, 4 dB feline loss, 4 dB duplexer and circulator loss, and 10 dB antenna gain? 6757. 317 W 6758. 2000 W 6759. 126 W 6760. 260 W 6761. 6762. Which of the following is standardized as part of GSM phase 2+ that can offer theoretical data speeds of upto 115 kbit/s? 6763. EDGE 6764. GPRS 6765. WAP 6766. Bluetooth 6767. 6768. A ______is essentially a cell site that is mounted on a flatbed tractor-trailer used for emergency purposes. 6769. COW 6770. BULL 6771. CALF 6772. PONY 6773. 6774. Which of the following best describes a dip-meter? 6775. An SWR meter 6776. A counter 6777. A variable LC oscillator with metered feedback current 6778. A field strength meter 6779. 6780. Which is space diversity system? 6781. Two or more antennas operating on two different frequencies? 6782. Two transmitters operating at same frequencies 6783. Two or more antennas operating on the same frequency 6784. Two antennas from two different transmitters 6785. 6786. What part or section of a TV receiver that separates the sound and video signals? 6787. IF stage 6788. Video amplifier 6789. Video detector 6790. Burst separator 6791. 6792. What is the channel number of an FM station with a carrier frequency of 99.5 MHz? 6793. 256 6794. 258 6795. 257 6796. 259 6797. 6798. In a triple conversion superheterodyne receiver, diode mixer stages are operated 6799. In the linear region 6800. In the nonlinear region 6801. As class A amplifiers 6802. As class B amplifiers 6803. 6804. In ISDN, what is the basic access B channel data rate? 6805. 32 kbps 6806. 64 kbps 6807. 144 kbps 6808. 16 kbps 6809. 6810. What is the channel spacing for MF-HF voice frequencies? 6811. 2.8 kHz 6812. 500 Hz 6813. 3.5 kHz 6814. 3 kHz 6815. 6816. What is the quantization signal-to-noise ratio if an 8-bit PCM code is used? 6817. 40 dB 6818. 50 dB 6819. 60 dB 6820. 65 dB 6821. 6822. What is the emission designation of a single sideband reduced carrier signal? 6823. H3E 6824. J3E 6825. R3E 6826. B8E 6827. 6828. What is the most commonly used intermediate frequency of radar receivers? 6829. 40 MHz 6830. 60 MHz 6831. 70 MHz 6832. 30 MHz 6833. 6834. The input signal of a travelling wave tube is introduced at 6835. Cathode 6836. Anode 6837. Cathode end of the helix 6838. Collector end of the helix 6839. 6840. What determines the ability of radar to determine the bearing to a target? 6841. Speed of light 6842. Speed of target 6843. Antenna directivity 6844. Frequency of signal 6845. 6846. What is the minimum number of bits required in a PCM code for a range of 10,000? 6847. 12 6848. 9 6849. 14 6850. 10 6851. 6852. The antenna current is doubled when the modulation index is doubled in ______AM system. 6853. A5C 6854. A3J 6855. A3 6856. A3H 6857. 6858. Which of the following is not a bounded medium? 6859. Coaxial line 6860. Two-wire line 6861. Waveguide 6862. Free space 6863. 6864. What is affected by the distance between the listener and the source of the sound because the intensity varies inversely with the square of the distance? 6865. Volume 6866. Pitch 6867. Loudness 6868. Frequency 6869. 6870. Comparing the capacities of a DVD and an ordinary CD, DVD is ______time bigger than CD. 6871. 10 6872. 20 6873. 15 6874. 25 6875. 6876. Locking on to a defined target is known as 6877. Homing 6878. Referencing 6879. Searching 6880. Defining 6881. 6882. What causes the maximum usable frequency to vary? 6883. The temperature of the ionosphere 6884. The speed of the winds in the upper atmosphere 6885. The type of weather just below the ionosphere 6886. The amount of radiation received from the sun 6887. 6888. What limits the sensitivity of a receiver? 6889. The power supply of the receiver 6890. The power output of a transmitter 6891. The noise floor of the receiver 6892. The distance between the transmitter and receiver 6893. 6894. What is the standard test tone used for audio measurements? 6895. 100 Hz 6896. 500 Hz 6897. 1000 Hz 6898. 2000 Hz 6899. 6900. What causes image interference? 6901. Low gain 6902. High IF 6903. Poor front-end selectivity 6904. Low signal-to-noise ratio 6905. 6906. What frequency band is referred to as the metric waves? 6907. VHF 6908. UHF 6909. HF 6910. SHF 6911. 6912. A waveguide passive component that brings a smooth change in the direction of axis maintained perpendicular to the plane of polarization? 6913. L bend 6914. H bend 6915. T bend 6916. X bend 6917. 6918. How far is the visual carrier from the lowest frequency in the spectrum of a monochrome TV broadcast channel following the NTSC standard? 6919. 1.5 MHz 6920. 1.25 MHz 6921. 4.5 MHz 6922. 0.25 MHz 6923. 6924. What aircraft deviation is measured by an ILS localizer? 6925. Altitude 6926. Ground speed 6927. Vertical 6928. Horizontal 6929. 6930. Skip zone is otherwise known as 6931. Empty zone 6932. Shadow zone 6933. Null zone 6934. Zone of silence 6935. 6936. In the American standard, the aural transmitter maximum radiated power is _____ of peak visual transmitter power. 6937. 10 % 6938. 30 % 6939. 20 % 6940. 40 % 6941. 6942. What character signifies the start of the test for Bisync? 6943. STX 6944. SOH 6945. BCC 6946. ETX 6947. 6948. A low frequency audible periodic variation in pitch of sound output in high fidelity sound reproduction system? 6949. Flutter 6950. Wow 6951. String vibration 6952. Radio sound 6953. 6954. When can a corporation or association incorporated under the Philippine laws and with foreign investors be granted radio station license? 6955. When 60% of the capital is owned by Filipino citizens 6956. When 50% of the capital is owned by Filipino citizens 6957. When the chairman of the board is a Filipino 6958. When the president of the corporation/association is a Filipino 6959. 6960. ______is a term in the test language for noise testing in telephone circuits that means a one-syllable word consisting of a consonant, a vowel, and another consonant. 6961. Logatom 6962. Nosfer 6963. Ore 6964. Belcore 6965. 6966. Why are frequency modulation transmitters more efficient? 6967. Because their power is increased by class C amplifiers 6968. Because their power is increased by class A amplifiers 6969. Because their power is increased by class B amplifiers 6970. Because their power is increased by class AB amplifiers 6971. 6972. A 1000W carrier is amplitude modulated to a depth of 85%. Calculate the total power of the modulated wave? 6973. 1361.25 W 6974. 680.62 W 6975. 1425 W 6976. 712.5 W 6977. 6978. Which is not an ITU sector? 6979. ITU-W 6980. ITU-R 6981. ITU-T 6982. ITU-D 6983. 6984. What is the process of cancelling the effect on internal device capacitance in radio transmitters? 6985. Degaussing 6986. Neutralization 6987. Ionization 6988. Stabilization 6989. 6990. Which of the following is the basic synthesizer circuit? 6991. Frequency divider 6992. Frequency multiplier 6993. PLL 6994. Mixer 6995. 6996. Which one is not an important characteristic of the physical layer? 6997. Electrical 6998. Logical 6999. Mechanical 7000. All of the choices 7001. 7002. What is the typical separation between the two conductors in a parallel wire line? 7003. 0.001 to 0.01 m 7004. 200 to 500 mm 7005. 0.635 to 15.24 cm 7006. 2.5 to 5 in. 7007. 7008. In t-carrier system, t3 has a bit rate of 7009. 560.160 Mbps 7010. 44.376 Mbps 7011. 44.736 Mbps 7012. 560.106 Mbps 7013. 7014. In radio signal emission designation, the fifth symbol means 7015. Details of signals 7016. Type of information transmitted 7017. Nature of multiplexing 7018. Nature of signal modulating the main carrier 7019. 7020. What is the channel spacing for SITOR frequencies? 7021. 500 Hz 7022. 170 Hz 7023. 300 Hz 7024. 3 kHz 7025. 7026. Which of the following is the new name of CCITT? 7027. ITU-T 7028. ITU-R 7029. ITU-S 7030. ITU-D 7031. 7032. Which of the following frequencies is normally used for distress and safety communications? 7033. 4209.5 kHz 7034. 490 kHz 7035. 518 kHz 7036. 2174.5 kHz 7037. 7038. What is the difference between available power and power budget? 7039. Power margin 7040. Extra power 7041. Fade margin 7042. System gain 7043. 7044. A matched termination in which the electromagnetic energy is absorbed by water. 7045. Maximum power transfer 7046. Load 7047. Load water 7048. Basin 7049. 7050. What do you call the electrical conduction in a photosensitive material which is not exposed to radiation? 7051. Dark conductance 7052. Pure conductance 7053. Black out 7054. Super conductance 7055. 7056. How many sidebands are present in the J3E mode? 7057. Two sidebands and a carrier 7058. One upper sideband 7059. One lower sideband 7060. Two carriers and one sideband 7061. 7062. A component that samples the microwave signal travelling in one direction down to the transmission line 7063. Isolator 7064. Combiner 7065. Directional coupler 7066. Attenuator 7067. 7068. What does OMB stand for? 7069. Optical media board 7070. Organization of medical biologist 7071. Optical medium board 7072. Optimum main board 7073. 7074. A test method of comparing two audio systems by switching inputs so that the same recording is heard in rapid succession over one given system and then the other. 7075. B test 7076. A test 7077. AB test 7078. C test 7079. 7080. And ITU-T specification code that deals with the telephone circuits. 7081. X series 7082. T series 7083. V series 7084. I series 7085. 7086. What digital carrier transmits a digital signal at 274.176 Mbps? 7087. T1 7088. T3 7089. T2 7090. T4 7091. 7092. What signal-to-noise ratio is required for satisfactory television reception? 7093. 10 dB 7094. 30 dB 7095. 40 dB 7096. 20 dB 7097. 7098. How many telephone channels are there in AT 2 line? 7099. 50 7100. 90 7101. 83 7102. 96 7103. 7104. What optical source radiates light uniformly in all directions? 7105. Isotropic source 7106. Lambertian source 7107. Voltage source 7108. Ideal source 7109. 7110. What is the spectrum of stereophonic FM signal? 7111. 19 to 38 kHz 7112. 30 to 53 kHz 7113. 59.5 to 74.5 kHz 7114. 88 to 108 MHz 7115. 7116. What is the required quality factor for an SSB filter with the following data: center frequency= 1 MHz, the desired attenuation level of the unwanted sideband= 80 dB and the separation between sidebands= 200 Hz? 7117. 1,250 7118. 12,500 7119. 125,000 7120. 25,000 7121. 7122. What do you call the reflection of a part of incident light at the interface of two media that have different refractive indices? 7123. Snell’s reflection 7124. Fresnel reflection 7125. Lambertian reflection 7126. Huygen’s reflection 7127. 7128. Which conference in the ITU-structure does the telecommunication standardization bureau report? 7129. World telecommunication standardization conference 7130. ITU-development sector 7131. Radio regulation board 7132. The secretary general 7133. 7134. What region around a broadcasting transmitter in which satisfactory reception of broadcasting signal is not obtained? 7135. Fringe area 7136. Primary are 7137. Secondary area 7138. Tertiary area 7139. 7140. What do you call the random noise seen on radar display screen? 7141. Impulse noise 7142. Atmospheric noise 7143. Grass 7144. Johnson noise 7145. 7146. Which of the following antennas receives signals equally well from all directions in a horizontal plane? 7147. Hetz antenna 7148. Vertical Marconi antenna 7149. Yagi antenna 7150. Helical antenna 7151. 7152. Where is the brightness control located in a TV? 7153. The audio section 7154. The video section 7155. The grid-cathode circuit 7156. The front panel 7157. 7158. What is the term used in telephony and telegraphy for irregular disturbing radiation due to various causes and in a particular produced by arc transmitters causing a rushing sound in receiving telephones? 7159. Fax tone 7160. Mush 7161. Hiss 7162. Crosstalk 7163. 7164. What device in a waveguide system used for stopping or diverting electromagnetic wave as desired? 7165. Mechanical switch 7166. Electric switch 7167. Push-button switch 7168. Waveguide switch 7169. 7170. What is the maximum power that can be obtained from a microwave tube at 10 GHz? 7171. 500 W 7172. 10 W 7173. 50 W 7174. 20 W 7175. 7176. What do you call a cable consisting of twisted pairs of conductors, each separately insulated? 7177. Microstrip line 7178. Strip line 7179. Quad 7180. Coaxial cable 7181. 7182. What mixer type has the lowest spurious signals? 7183. Double-balanced 7184. Single-balanced 7185. Super-heterodyner 7186. Heterodyner 7187. 7188. What are the electromagnetic radiations of wavelengths less than 300 angstroms? 7189. X-rays 7190. Ultraviolet rays 7191. Infrared 7192. Microwaves 7193. 7194. What is known as the alignment of the three color guns to a common point? 7195. Confetti 7196. Divergence 7197. Convergence 7198. Synchronization 7199. 7200. What is the department order that governs commercial radio operator? 7201. Department Order No. 5 7202. Department Order No. 23 7203. Department Order No. 88 7204. Department Order No. 44 7205. 7206. The computer which initiates information transfer 7207. Master 7208. Station 7209. Slave 7210. Mainframe 7211. 7212. Which of the following antennas require good grounding? 7213. Yagi antenna 7214. Hertz antenna 7215. Marconi antenna 7216. Isotropic antenna 7217. 7218. Which circuit detects frequency modulated signal? 7219. Modulator 7220. Discriminator 7221. Demodulator 7222. Modem 7223. 7224. What synchronization is provided so that the start and end of message is identified? 7225. Carrier 7226. Character 7227. Bit 7228. Clock 7229. 7230. A form of regenerative repeater for transmitting signals over a long cable received through a relay in a clearer form. 7231. Active generator 7232. Active repeater 7233. Interpolator 7234. Audio generator 7235. 7236. What is the minimum propagation delay of a geostationary satellite? 7237. 278 ms 7238. 239 ms 7239. 300 ms 7240. 600 ms 7241. 7242. In measuring crosstalk using dBx unit the reference power is 7243. 1 mW 7244. 1 W 7245. 1 pW 7246. 6 mW 7247. 7248. A spot on the sun’s visible surface where the magnetic flux lines converge? 7249. Sunspot 7250. Filament 7251. Solar spot 7252. Prominence 7253. 7254. ______is a slow moving large mass of plasma on the sun’s surface. 7255. Filament 7256. Solar flare 7257. Prominence 7258. Proton flare 7259. 7260. ______is slow moving “cord-like” mass of plasma across the sun’s surface. 7261. Filament 7262. Solar flare 7263. Prominence 7264. Solar spot 7265. 7266. At what particular wavelength is solar flux measured? 7267. 10.7 mm band 7268. 10.7 m band 7269. 10.7 cm band 7270. 10.7 nm band 7271. 7272. What is the approximate intensity of the magnetic field at the earth’s surface? 7273. 32,000 nT 7274. 62,000 nT 7275. 32,000 µT 7276. 62,000 µT 7277. 7278. What is the intensity of the magnetic field at the earth’s north pole? 7279. 32,000 nT 7280. 62,000 nT 7281. 32,000 µT 7282. 62,000 µT 7283. 7284. What do you call a satellite weighing less than 1 kg? 7285. Nanosat 7286. Picosat 7287. Femtosat 7288. Microsat 7289. 7290. The first creature in space was carried by which of the following spacecrafts in November 3, 1957? 7291. Sputnik 1 7292. Sputnik 3 7293. Sputnik 2 7294. Explorer 1 7295. 7296. The wireless evolution is achieved through the GSM family of wireless technology platforms which include but except one of the following. Which one is NOT a member of the GSM family? 7297. GSM 7298. EDGE 7299. GPRS 7300. CDMA 7301. 7302. Which of the following is an enhancement of GSM including the GPRS? 7303. 1G 7304. 2.5G 7305. 2G 7306. 3G 7307. 7308. A low power, short range wireless technology designed to provide a replacement for serial cables is called ______. 7309. WAP 7310. GPRS 7311. Bluetooth 7312. EDGE

7313. 7314. 7315. 7316. 7317. 7318. 7319. 7320. 7321. 7322. 7323. 7324. 7325. 7326. 7327. 7328. 7329. 7330. 7331. 7332. 7333. 7334. 7335. 7336. 7337. 7338. 7339. 7340. 7341. Noise Chapter 4 (3001 Questions in Communications Engineering-EXCEL REVIEW CENTER) 7342. What is the non-continuous noise of irregular pulses or spikes of duration with high amplitudes? 7343. Wander 7344. Jitter 7345. Hits 7346. Singing 7347. What theorem sets a limit on the maximum capacity of a channel with a given noise level? 7348. Nyquist theorem 7349. Hartley law 7350. Shannon-Hartley theorem 7351. Shannon theorem 7352. Quantizing noise occurs in 7353. PCM 7354. PLM 7355. PDM 7356. PAM 7357. Noise always affects the signal in a communications systems at the ______. 7358. transmitter 7359. channel 7360. information source 7361. destination 7362. ______is the random and unpredictable electric signals from natural causes, both internal and external to the system. 7363. Interference 7364. Attenuation 7365. Distortion 7366. Noise 7367. Noise from random acoustic or electric noise that has equal energy per cycle over a specified total frequency band. 7368. Gaussian noise 7369. Whiter noise 7370. Thermal noise 7371. All of the above 7372. Which causes a quantization noise in PCM system? 7373. Serial transmission errors 7374. The approximation of the quantized signal 7375. The synchronization between encoder and decoder 7376. Binary coding techniques 7377. A particular circuit that rids FM of noise 7378. Detector 7379. Discriminator 7380. Phase Shifter 7381. Limiter 7382. What is the reference noise temperature in degrees Celsius? 7383. 17 7384. 273 7385. 25 7386. 30 7387. Unwanted radio signal on assigned frequency. 7388. Splatter 7389. RFI 7390. Noise 7391. EMI 7392. What is the reliable measurement for comparing amplifier noise characteristics? 7393. A. Thermal agitation noise 7394. B. Noise factor 7395. C. Noise margin 7396. D. Signal-to-noise 7397. 7398. ______is measured on a circuit when it is correctly terminated but does not have any traffic. 7399. White noise 7400. Galactic noise 7401. Impulse noise 7402. Atmospheric noise 7403. Which standard recommends crosstalk limits? 7404. CCIT G.152 7405. CCIT G.150 7406. CCIT G.151 7407. CCIT G.161 7408. Which standard is utilized in intermodulation noise rates on PCM audio channels? 7409. CCIT Rec. G.151 7410. CCIT Rec. G.172 7411. CCIT Rec. G.190 7412. CCIT Rec. G.190 7413. What is the reference frequency of CCIT phosphomeric noise measurement? 7414. 800 Hz 7415. 1000 Hz 7416. 1500 Hz 7417. 3400 Hz 7418. Reference temperature use in noise analysis 7419. 75 K 7420. 250 K 7421. 290 K 7422. 300 K 7423. Which noise is produced by lighting discharges in thunderstorms? 7424. White noise 7425. Extraterrestrial noise 7426. Industrial noise 7427. Atmospheric noise 7428. Man-made noise is usually from ______. 7429. transmission over power lines and by ground wave 7430. sky-wave 7431. space-wave 7432. troposphere 7433. nif stands for 7434. Non-intrinsic figure 7435. Noise improvement factor 7436. Narrow intermediate frequency 7437. Noise interference figure 7438. Industrial noise frequency is between _____. 7439. 0 to 10 KHz 7440. 160 MHz to 200 MHz 7441. 15 to 160 MHz 7442. 200 to 3000 MHz 7443. External noise fields are measured in terms of ______. 7444. rms values 7445. dc values 7446. average values 7447. peak values 7448. Form of interference caused by rain or dust storms. 7449. Precipitation static 7450. Shot-noise 7451. Galactic noise 7452. Impulse noise 7453. At 17˚ C, the noise voltage generated by 5kΩ resistor, operating over a bandwidth of 20KHz is 7454. 1.3 nV 7455. 1.3 µV 7456. 1.3 pV 7457. 1.3 mV 7458. ______is an electric noise produced by thermal agitation of electrons in conductor and semiconductor. 7459. External noise 7460. Internal noise 7461. Thermal noise 7462. Flicker 7463. Three identical circuits having 10 dB signal noise-to-noise ratio each are connected in tandem with each other, what is the overall S/N? 7464. 5.23 dB 7465. 14.77dB 7466. 30 dB 7467. 40 dB 7468. The noise figure of the first circuit in tandem connection is 10.5 dB while its power gain is 15, what is the over all noise figure if the second circuit has a noise figure of 11 dB? 7469. 11.59 dB 7470. 11.23 dB 7471. 10.79 dB 7472. 10.5 dB 7473. Is the interference coming from other communications channels? 7474. Jitter 7475. Crosstalk 7476. RFI 7477. EMI 7478. What is the reference noise level? 7479. 10 pW 7480. 0 dBm 7481. 1mW 7482. -90 dBm 7483. What is the unit of noise power of psophometer? 7484. pWp 7485. dBa 7486. dBm 7487. dBrn 7488. A large emission of hydrogen from the sun that affects communications. 7489. Solar flare 7490. Cosmic disturbance 7491. Ballistic disturbance 7492. Solar noise 7493. Atmospheric noise is known as ______noise. 7494. static 7495. cosmic 7496. solar 7497. lunar 7498. Standard design reference for environmental noise temperature. 7499. 300 K 7500. 290 K 7501. 32 ˚F 7502. 212˚F 7503. Absolute temperature in Kelvin. 7504. ˚C +273 7505. ˚C+75 7506. ˚C+19 7507. ˚C +290 7508. If bandwidth is doubled, the signal power is ______. 7509. not changed 7510. quadrupled 7511. tripled 7512. doubled 7513. Name one or more sources of noise bearing on electronic communications. 7514. Steam boiler 7515. Galaxies 7516. Internal combustion engine 7517. Both B and C 7518. The transmitter technique adopted to reduce the noise effect of the preceding question is called 7519. noise masking 7520. anitnoise 7521. noise killing 7522. preemphasis 7523. Deemphasis in the receiver in effect attenuates modulating signal components and noise in what frequency range? 7524. dc 7525. low 7526. intermediate 7527. high 7528. Atmospheric noise or static is not a great problem 7529. at frequencies below 20 MHz 7530. at frequencies below 5 MHz 7531. at frequencies above 30 MHz 7532. at frequencies above 1 MHz 7533. What is the proper procedure for suppressing electrical noise in a mobile station? 7534. Apply shielding and filtering where necessary 7535. Insulate a all plain sheet metal surfaces from each other 7536. Apply anti-static spray liberally to all nonmetallic 7537. Install filter capacitors in series with all dc wiring 7538. Where is the noise generated that primarily determines the signal-to-noise ratio in a VHF (150MHz) marine-band receiver? 7539. Man-made noise 7540. In the atmosphere 7541. In the receiver front end 7542. In the ionosphere 7543. The difference between signal strength at a given point and a reference level is______. 7544. power 7545. dBm 7546. level 7547. ratio 7548. Interfering effect of noise, C message weighted, is ______. 7549. dBa 7550. dBm 7551. dBmc 7552. dB 7553. F1A weighting refers to ______. 7554. -90 dBm 7555. dBrnc0 7556. dBrnc 7557. F1A handset 7558. Reading a 58 dBrnC on your Western Electric 3A test set at a +7 test point is equal to ______dBrnc0. 7559. 58 7560. 51 7561. 65 7562. 27 7563. Reading a 58 dBrn, at a +7 test point is equal to ______dBa0. 7564. 26 7565. 65 7566. 51 7567. 46 7568. A reading of -50 dBm on the disturbing pair, and -80 on the disturbed pair equals _____ dB of crosstalk coupling. 7569. 20 7570. 30 7571. 60 7572. 25 7573. Power is ______. 7574. actual amount of power reference to 1mW 7575. logarithmic ratio of two powers 7576. definite amount of energy per time period 7577. current flow per time period 7578. 15 dBa F1A weighted, equals ______. 7579. -90 dBm 7580. -82 dBm 7581. -85 dBm 7582. -70 dBm 7583. You are measuring noise in a voice channel with a Lenkurt 601A, F1A weighting network and a flat meter. Your meter reads -47dBm. What is this reading in dBa? 7584. 77 dBa 7585. 35 dBa 7586. 38 dBa 7587. 32 dBa 7588. You are measuring noise at a +3 dB level point, using the Lenkurt 601A, F1A weighting network, and a flat meter. The meter reading is -57dBm. This is ______dBa0. 7589. 20 7590. 15 7591. 25 7592. 17 7593. You are measuring noise at a -6 dB level point, using the Lenkurt 601A, F1A weighting network, and a flat meter. The meter reading is -59 dBm. This is ______dBa0. 7594. 24 7595. 12 7596. 23 7597. 32 7598. A measurement of -75 dBm, C-message weighted, would be ______dBrnc. 7599. 8 7600. 7 7601. 9 7602. 15 7603. Your Western Electric 3A test set meter reading is -23 dBm at at test point level of -8 dB. This is ______dBrnc0. 7604. 75 7605. 29 7606. 30 7607. 31 7608. At what power level does a 1 KHz tone cause zero interference (144 weighted)? 7609. 90 dB 7610. 90 dBm 7611. -90 dBm 7612. -90 dBm 7613. Reference noise is ______. 7614. a 1000 Hz, -90 dBm tone 7615. a noise that creates the same interfering effect as a 1000Hz, -90dBm tone 7616. a noise that creates zero dBrn in a voice channel 7617. B and C above 7618. A practical dBrn measurement will almost always in a ______number. 7619. positive 7620. negative 7621. imaginary 7622. fractional 7623. What is the reference level for noise measurement, F1A weighted? 7624. -90 dBm 7625. -82 dBm 7626. -67 dBm 7627. -85 dBm 7628. What is the reference tone level for dBrn? 7629. -90 dBm 7630. -82 dBm 7631. -67 dBm 7632. -85 dBm 7633. What is the reference tone level for dBa? 7634. -90 dBm 7635. -82 dBm 7636. -67 dBm 7637. -85 dBm 7638. Atmospheric noise becomes less severe at frequencies 7639. above 30 MHz 7640. below 30 MHz 7641. above 3000 kHz 7642. below 3000kHz 7643. Indicate the noise whose sources are in category different from that of the other three? 7644. Solar noise 7645. Cosmic noise 7646. Atmospheric noise 7647. Galactic noise 7648. Indicate the false statement. 7649. Industrial noise is usually of the impulse type 7650. Static is caused by lightning discharges in thunderstorms and other natural electric disturbances occurring in the atmosphere 7651. Distant stars are another source of man-made noise 7652. Flourescent lights are another source of man-made noise 7653. Which of the following is not a source of industrial noise? 7654. Automobile ignition 7655. Sun 7656. Electric Motors 7657. Leakage from high voltage line 7658. Indicate the false statement 7659. The noise generated in a resistance or the resistive component of any impedance is random. 7660. Random noise power is proportional to the bandwidth over which is measured 7661. A random voltage across the resistor does not exist 7662. All formula referring to random noise are applicable only to the value of such noise. 7663. The value of the resistor creating thermal noise is doubled. The noise power generated is therefore. 7664. halved 7665. quadrupled 7666. doubled 7667. unchanged 7668. Indicate the false statement. 7669. HF mixer are generally noisier than HF amplifiers. 7670. Impulse noise voltage is dependent on bandwidth 7671. Thermal noise is independent of the frequency at which is measured. 7672. Industrial noise is usually of the impulse type. 7673. An amplifier operating over the frequency range of 455 to 460 kHz has a 200 kΩ input resistor. What is the RMS noise voltage at the input to this amplifier if the ambient temperature is 17˚C ? 7674. 40 µV 7675. 4.0 µV 7676. 400 µV 7677. 4.0 mV 7678. The first stage of a two-stage amplifier has a voltage gain of 10, a 600 Ω input resistor, a 1600Ω equivalent noise resistance and 27kΩ output resistor. For the second stage, these values are 25, 81kΩ, 19kΩ, and 1MΩ, respectively. Calculate the equivalent input-noise resistance of this two stage amplifier. 7679. 2,518 kΩ 7680. 2,518 Ω 7681. 251.8 Ω 7682. 12,518 Ω 7683. The noise output of a resistor is amplified by a noiseless amplifier having a gain of 60 and a bandwidth of 20 kHz. A meter connected at the output of the amplifier reads 1mV RMS. If the bandwidth of the amplifier is reduced to 5kHz, its gain remaining constant, what does the meter read now? 7684. 0.5 mV 7685. 0.5 µV 7686. 5.0 mV 7687. 5.0 µV 7688. The front-end of a television receiver, having a bandwidth of 7Mhz, and operating at a temperature of 27˚C , consists of an amplifier having a gain of 15 followed by a mixer whose gain is 20. The amplifier has a 300 Ω input resistor and a shot noise equivalent resistance of 500Ω; for the mixer, these values are 2.2kΩ and 13.5kΩ respectively, and the load resistance of the mixer is 470 kΩ. Calculate the equivalent noise resistance for this television receiver. 7689. 8760 Ω 7690. 875Ω 7691. 8.76Ω 7692. 0.876Ω 7693. One of the following is not a useful quantity for comparing the noise performance receivers. 7694. Input noise voltage 7695. Equivalent noise resistance 7696. Noise temperature 7697. Noise figure. 7698. Indicate the false statement. Noise figure is defined as 7699. the ratio of the S/N power supplied at the input terminal of a receiver or amplifier to the S/N power supplied to the output or load resistor 7700. noise factor expressed in decibels 7701. an unwanted form of energy tending to interfere with the proper and easy reception and reproduction of wanted signals 7702. S/N of an ideal system divided by S/N at the output of the receiver or amplifier under test, both working at the same temperature over the same bandwidth and fed from the same source 7703. Calculated the noise figure of the amplifier whose Req equals 2518Ω (RT=600Ω) if its driven by a generator whose output impedance is 50Ω. 7704. 39.4 7705. 3.94 7706. 394 7707. 0.394 7708. Calculate the noise figure of the receiver whose RF amplifier has an input resistance of 1000Ω and an equivalent shot-noise resistance of 2000Ω, a gain of 25 and load resistance of 125 kΩ. Given that the bandwidth is 1.0MHz and the temperature is 20˚C, and that the receiver is connected to an antenna with an impedance of 75Ω. 7709. 30.3 7710. 3.03 7711. 303 7712. .303 7713. A receiver connected to an antenna whose resistance is 50 Ω has an equivalent noise resistance of 30Ω. Calculate its equivalent noise temperature if the noise figure is equal to 1.6. 7714. 17.4 K 7715. 174K 7716. 1.74K 7717. 17K 7718. Most internal noise comes from 7719. Shot noise 7720. Transit-time noise 7721. Thermal agitation 7722. Skin effect 7723. Which of the following is not a source of external noise? 7724. Thermal agitation 7725. Auto ignition 7726. The sun 7727. Fluorescent lights 7728. Noise can be reduced by 7729. widening the bandwidth 7730. narrowing the bandwidth 7731. increasing temperature 7732. increasing transistor current levels 7733. Noise at the input to the receiver can be as high as several 7734. microvolts 7735. milivolts 7736. volts 7737. kilo volts 7738. Which circuit contributes most of the noise in a receiver? 7739. IF amplifier 7740. Demodulator 7741. AF amplifier 7742. Mixer 7743. Which noise figure represents the lowest noise in receiver? 7744. 1.6 dB 7745. 2.1 dB 7746. 2.7 dB 7747. 3.4 dB 7748. The transistor with the lowest noise figure in the microwave region is a 7749. MOSFET 7750. Dual-gate MOSFET 7751. JFET 7752. MESFET 7753. What is the noise voltage across a 300Ω input resistance to a TV set with a 6MHz bandwidth and temperature of 30˚C? 7754. 2.3 µV 7755. 3.8µV 7756. 5.5µV 7757. 5.4µV 7758. Which of the following types of noise becomes of great importance at frequencies? 7759. Shot noise 7760. Random noise 7761. Impulse noise 7762. Transit-time noise 7763. The solar cycle repeats the period of great electrical disturbance approximately every 7764. 11 years 7765. 10 years 7766. 9 years 7767. 8 years 7768. The square of the thermal noise voltage generated by a resistor is proportional to 7769. its resistance 7770. its temperature 7771. the bandwidth over which it is measured 7772. All of the above 7773. Noise occurring in the presence of signal resulting from a mismatch between the exact value of an analog signal and the closet available quantizing step in a digital coder. 7774. Quantizing noise 7775. Thermal noise 7776. Impulse noise 7777. Crosstalk 7778. Noise consisting of irregular pulses of short duration and relatively high amplitude, 7779. Quantizing noise 7780. Tone interference 7781. Impulse noise 7782. Cross talk 7783. Noise that occurs via capacitive or inductive coupling in a cable. 7784. Crosstalk 7785. Quantizing noise 7786. Reference noise 7787. Tone interference 7788. Sources of impulse noise induced in communication channels. 7789. Erroneous digital coding bit caused by an error on a transmission facility 7790. Transients due to relay operation 7791. Crosstalk from dc signaling systems 7792. All of these 7793. Crosstalk due to incomplete suppression of sidebands or to intermodulation of two or more frequency-multiplexed channels which is unintelligible is classified as 7794. Impulse noise 7795. Thermal noise 7796. Quantizing noise 7797. Miscellaneous noise 7798. ______is device that measures the internal open circuit voltage of an equivalent noise generator having an impedance of 600Ω and delivering noise power to a 600 Ω load. 7799. Psophometer 7800. Barometer 7801. Reflectometer 7802. Voltmeter 7803. External noise originating outside the solar system 7804. Cosmic noise 7805. Solar noise 7806. Thermal noise 7807. Lunar noise 7808. A noise whose source is within the solar system. 7809. Solar noise 7810. Thermal noise 7811. Cosmic noise 7812. Johnson Noise 7813. The total noise power present in a 1-Hz bandwidth . 7814. Noise density 7815. Noise figure 7816. Noise limit 7817. Noise intensity 7818. Which of the following is not a way of minimizing if not eliminating noise? 7819. Use redundancy 7820. Increase transmitted power 7821. Reduce signaling rate 7822. Increase channel bandwidth 7823. What is the primary cause of atmospheric noise? 7824. Thunderstorm 7825. Lightning 7826. Thunderstorm and lightning 7827. Weather condition 7828. What do you call the noise coming from the sun and stars? 7829. Black-body noise 7830. Space noise 7831. Galactic noise 7832. All of these 7833. The major cause of atmospheric or static noise are 7834. Thunderstorms 7835. Airplanes 7836. Meteor showers 7837. All of these 7838. Which of the following low noise transistors is commonly used at microwave frequencies? 7839. MOSFET 7840. GASFET 7841. MESFET 7842. JFET 7843. 7844. 7845. 7846. Satellite Communications Chapter 10(3001 Questions in Communications Engineering-EXCEL REVIEW CENTER 7847. Which of the following is the first active satellite? 7848. Echo I 7849. Telstar I 7850. Early Bird 7851. Sputnik I 7852. Which of the following is the first commercial satellite? 7853. Early Bird 7854. Telstar 7855. Explorer 7856. Courier 7857. What is the first passive satellite transponder? 7858. Sun 7859. Early Bird 7860. Score 7861. Moon 7862. The first satellite to receive and transmit simultaneously 7863. Intelsat I 7864. Agila I 7865. Syncorn I 7866. Telstar I 7867. A helical antenna is used for satellite tracking because of 7868. circular polarization 7869. maneuverability 7870. beamwidth 7871. gain 7872. Repeaters inside communications satellites are known as 7873. Trancievers 7874. Transponders 7875. Transducers 7876. TWT 7877. Considered as the unsolved problem in satellite system 7878. Coverage 7879. Cost 7880. Access 7881. Privacy 7882. ______is a satellite that rotates around the earth in a low-altitude elliptical or circular pattern. 7883. Geosynchronous satellite 7884. Nonsynchronous satellite 7885. Prograde satellite 7886. Retrograde satellite 7887. Is the geographical representation of a satellite antenna radiation pattern 7888. Footprint 7889. Spot 7890. Earth 7891. Region 7892. The smallest beam of a satellite antenna radiation pattern 7893. Zone beam 7894. Hemispheric beam 7895. Spot beam 7896. Global beam 7897. A satellite beam that covers almost 42.4% of the earths surface. 7898. Zone beam 7899. Hemispheric beam 7900. Spot beam 7901. Global beam 7902. What is the frequency range of C-band? 7903. 8.5 to 12.5 GHz 7904. 3.4 to 6.425 GHz 7905. 12.95 to 14.95 GHz 7906. 27.5 to 31 GHz 7907. A satellite signal transmitted from a satellite transponder to earth’s station. 7908. Uplink 7909. Downlink 7910. Terrestrial 7911. Earthbound 7912. Collects very weak signals from a broadcast satellite 7913. Helical antenna 7914. Satellite dish 7915. LNA 7916. TWT 7917. What is a device that detects both vertically and horizontally polarized signals simultaneously? 7918. Orthomode transducer 7919. Crystal detector 7920. Optoisolator 7921. Isomode detector 7922. ______detects the satellite signal relayed from the feed and converts it to an electric current, amplifies and lower its frequency. 7923. Horn antenna 7924. LNA 7925. Satellite receiver 7926. Satellite dish 7927. Is a loss of power of a satellite downlink signal due to earth’s atmosphere. 7928. Atmospheric loss 7929. Path loss 7930. Radiation loss 7931. RFI 7932. What height must a satellite be placed above the surface of the earth in order for its rotation to be equal to earth’s rotation? 7933. 26,426.4 miles 7934. 27,426.4 miles 7935. 23,426.4 miles 7936. 22,426.4 miles 7937. Point on the satellite obits closest to the earth. 7938. Apogee 7939. Perigee 7940. Prograde 7941. Zenith 7942. The earth area covered by a satellite radio beam. 7943. Beamwidth 7944. Bandwidth 7945. Footprint 7946. Zone 7947. What is the local oscillator (mixer) frequency of the satellite with an uplink frequency in GHz band? 7948. 3500 MHz 7949. 4500 MHz 7950. 2225 MHz 7951. 2555 MHz 7952. What kind of battery panels are used in some advance satellites 7953. Germanium based panels 7954. Silicon based panel 7955. Galium Phosphate solar panel array 7956. Galium Arsenide solar panel array 7957. Satellite engine uses 7958. jet propulsion 7959. ion propulsion system 7960. liquid fuel 7961. solar jet 7962. A satellite batter has more power but lighter. 7963. Lithium 7964. Leclanche 7965. Hydrogen 7966. Magnesium 7967. What kind of battery used by older satellites? 7968. Lithium 7969. Leclanche 7970. Hydrogen 7971. Magnesium 7972. VSAT was made available in 7973. 1979 7974. 1981 7975. 1983 7976. 1977 7977. What band does VSAT first operate? 7978. L-band 7979. X-band 7980. C-band 7981. Ku-band 7982. The first Philippine Mabuhay satellite has how many channels? 7983. 30 7984. 24 7985. 48 7986. 50 7987. The first Philippine Agila I will have how many transpoders. 7988. 36 7989. 48 7990. 24 7991. 12 7992. How may satellite orbital slots are requested by the Philippine Government from ITU? 7993. 2 7994. 4 7995. 6 7996. 8 7997. The location of AsiaSat I. 7998. 105.5˚East 7999. 151.5˚East 8000. 115.5˚East 8001. 170.5˚East 8002. AsiaSat I covers how many countries in Asia? 8003. 38 8004. 10 8005. 28 8006. 15 8007. The owner of AsiaSat 2 is 8008. Asia Satellite Telecommunications Company (ASTC) 8009. Japan Satellite System (JSAT) 8010. China Great Wall Industry Corporation 8011. Singapore Satellite Commision 8012. What is the approximate path loss from satellite-to-earth station? 8013. 100 dB 8014. 150 dB 8015. 175 dB 8016. 200 dB 8017. INTELSAT stands for 8018. Intel Satellite 8019. International Telephone Satellite 8020. International Telecommunications Satellite 8021. International Satellite 8022. The frequency of Ku band for satellite communications. 8023. 6/4 GHz 8024. 14/11 GHz 8025. 12/14 GHz 8026. 4/8 GHz 8027. A satellite cross-link means 8028. Earth-to-satellite link 8029. Satellite-to-earth link 8030. Satellite-to-satellite link 8031. None of these 8032. Earth station uses what type of antenna 8033. Despun antenna 8034. Helical antenna 8035. Toroidal antenna 8036. Cassegrain antenna 8037. What is the delay time for satellite transmission from earth transmitter to earth receiver? 8038. 0.5 s 8039. 1.0 s 8040. 5 ms 8041. 0.25 ms 8042. The bandwidth of C-band satellite frequency band in U.S. 8043. 500 GHz 8044. 1000 GHz 8045. 1000 MHz 8046. 500 MHz 8047. The most common device used as an LNA is 8048. zener diode 8049. tunnel diode 8050. IMPATT 8051. Shockley diode 8052. The radiation patterns of earth coverage antennas have a beamwidth of approxiamately 8053. 21˚ 8054. 5˚ 8055. 17˚ 8056. 35˚ 8057. A mobile satellite array has usually how many elements? 8058. 6 8059. 88 8060. 12 8061. 14 8062. In a typical mobile satellite array antenna if three elements are activated, how many elements are deactivated? 8063. 3 8064. 11 8065. 5 8066. 9 8067. What circuit is responsible in activating and deactivating adjacent antenna elements in a mobile satellite array? 8068. Radial divider 8069. Divider/combiner 8070. Radial combiner 8071. Radial multiplexer 8072. Most mobile satellite array uses ______in transforming 50 to 150 Ω impedance. 8073. stub 8074. balun 8075. quarter-wavelength transformer 8076. microstrip tapers. 8077. The switching from one element to the other element in a typical mobile satellite array. 8078. Series 8079. Radial 8080. Matrix 8081. Shunt 8082. A method of multiple accessing where a given RF channel bandwidth is divided inot smaller frequency band. 8083. CDMA 8084. ANIK-D 8085. TDMA 8086. FDMA 8087. What is the delay time for satellite transmissions from earth transmitter to earth receiver? 8088. 0.5 s 8089. 1s 8090. 5 ms 8091. 0.25 s 8092. As the height of a satellite orbit gets lower, the speed of the satellite ______. 8093. increases 8094. decreases 8095. remains the same 8096. None of the above 8097. The main function of a communications satellite is a/ an 8098. repeater 8099. reflector 8100. beacon 8101. observation platform 8102. The key electronic component in a communications satellite is the 8103. telemetry equipment 8104. on-board computer 8105. command and control system 8106. transponder 8107. A circular orbit around the equator with a 24-h period is called a/an 8108. elliptical orbit 8109. geostationary orbit 8110. polar orbit 8111. transfer orbit 8112. A satellite stay in orbit because the following two factors are balanced 8113. Satellite weight and speed 8114. Gravitational force and centrifugal force 8115. Centripetal force and speed 8116. Satellite weight and the pull of the moon and sun 8117. What is the height of a satellite in a synchronous equatorial orbit? 8118. 42000 mi 8119. 6800 mi 8120. 22,300 mi 8121. 35,860 mi 8122. Most satellites operate in which frequency band? 8123. 30 to 300 MHz 8124. 300 MHz to 3 GHz 8125. 3 GHz to 30 GHz 8126. Above 300 GHz 8127. The main power sources for a satellite are 8128. batteries 8129. solar cells 8130. fuel cells 8131. thermoelectric generators 8132. The maximum height of an elliptical orbit is called the 8133. Perigee 8134. Apex 8135. Zenith 8136. Apogee 8137. Batteries are used to power all satellite subsystems 8138. at all times 8139. only during emergencies 8140. during eclipse periods 8141. to give the solar arrays a rest 8142. The satellite subsystem that monitors and controls the satellite is the 8143. propulsion subsystem 8144. power subsystem 8145. communications subsystem 8146. telemetry, tracking, and command subsystem 8147. What is the basic technique used to stabilize a satellite? 8148. Gravity-forward motion balance 8149. Spin 8150. Thruster control 8151. Solar panel orientation 8152. The jet thrusters are usually fired to 8153. maintain altitude 8154. put the satellite into the transfer orbit 8155. inject the satellite in the geosynchronous orbit 8156. bring the satellite back to earth. 8157. Most commercial satellite activity occurs in which band(s)? 8158. L 8159. C and Ku 8160. X 8161. S and P 8162. How can multiple earth stations share a satellite on the same frequencies? 8163. Frequency reuse 8164. Multiplexing 8165. Mixing 8166. Frequency hopping 8167. What is the typical bandwidth of a satellite band? 8168. 36 MHz 8169. 40 MHz 8170. 70 MHz 8171. 500 MHz 8172. Which of the following is not usually a part of a transponder are defined by the 8173. LNA 8174. Mixer 8175. Modulator 8176. HPA 8177. The satellite communications channels in a transponder are defined by the 8178. LNA 8179. bandpass filter 8180. mixer 8181. input signals 8182. The HPAs in most satellite are 8183. TWTs 8184. Klystrons 8185. Vacuum tubes 8186. Magnetrons 8187. The physical location of a satellite is determined by its 8188. distance from the earth 8189. latitude and longitude 8190. reference to the stars 8191. position relative to the sun 8192. The receive GCE system in an earth station performs what function(s)? 8193. Modulation and multiplexing 8194. Up conversion 8195. Demodulation and demultiplexing 8196. Down conversion 8197. Which of the following types of HPA is not used in earth stations? 8198. TWT 8199. Transistor 8200. Klystron 8201. Magnetron 8202. What is the common up-converter and down-converter IF? 8203. 36 MHz 8204. 40 MHz 8205. 70 MHz 8206. 500 MHz 8207. What type of modulation is used on voice and video signals? 8208. AM 8209. FM 8210. SSB 8211. QPSK 8212. What modulation is normally used with digital data? 8213. AM 8214. FM 8215. SSB 8216. QPSK 8217. Which of the following is not a typical output from a GPS receiver? 8218. Latitude 8219. Speed 8220. Altitude 8221. Longitude 8222. The total space loss of transmission and reception for two ground stations with uplink frequency 8GHz and a downlink of 6 GHz with angle of elevations of 3˚ and 7˚ A respectively is 8223. 403 dB 8224. 100 dB 8225. 20 dB 8226. 215 dB 8227. The maximum propagation delay of a geostationary satellite is 8228. 278 ms 8229. 239 ms 8230. 300 ms 8231. 250 ms 8232. The total propagation delay time from transmission to reception of signals from a ground transmitter to ground receiver with angle of elevation at 10 degrees respectively is 8233. 273 ms 8234. 239 ms 8235. 275 ms 8236. 260 ms 8237. A satellite which simply reflects the signal without further amplification 8238. Passive satellite 8239. Active satellite 8240. Geostationary satellite 8241. Domestic satellite 8242. Essentially a satellite ______is a radio repeater in the sky 8243. transponder 8244. comparator 8245. duplexer 8246. billboard 8247. Satellite the orbits in a circular pattern with an angular velocity equal to that of the earth 8248. Geostationary 8249. Early Bird I 8250. Syncorn I 8251. Stationary satellite 8252. Satellite that provide services within a single country 8253. Domsat 8254. Comsat 8255. Regional 8256. Global 8257. The round-trip propagation delay between two earth stations through a geosynchronous satellite is 8258. 500 to 600 ms 8259. 300 to 400 ms 8260. 600 to 700 ms 8261. 400 to 500 ms 8262. The signal path from earth station satellite 8263. Uplink signal 8264. Reflected signal 8265. Incident signal 8266. Downlink signal 8267. Designed to receive a signal from a transmitting station on the ground and retransmit it to a receiving station located elsewhere 8268. Communication satellite 8269. Repeater 8270. Relay station 8271. Transponder 8272. The signal path from satellite to earth-based receiver. 8273. Downlink signal 8274. Uplink signal 8275. Incident signal 8276. Reflected signal 8277. A satellite position is measured by its ______angle with respect to the horizon. 8278. elevation 8279. depression 8280. azimuth 8281. critical 8282. The ______angle measures the satellite position clockwise from the direction of true north. 8283. azimuth 8284. elevation 8285. depression 8286. critical 8287. incidentally propose the geostationary scheme or orbit of the satellite in 1940s 8288. Arthur Clarke 8289. Carl Friedrich Gauss 8290. Samuel Morse 8291. Stephen Gray 8292. When the satellite are spaced 4˚ of the 360˚ complete circle, how many parking spaces or orbit slots are available? 8293. 90 8294. 85 8295. 95 8296. 80 8297. The control routine necessary to keep the satellite in position is referred to as 8298. station keeping 8299. station tracking 8300. station monitoring 8301. station maintaining 8302. Refers to the satellite orientation with respect to the earth 8303. Satellite altitude 8304. Satellite position 8305. Satellite location 8306. Satellite orbit 8307. The first intelsat satellite that was launched in 1965 was named 8308. Early Bird I 8309. Echo 8310. Telstar I 8311. Courier 8312. The first satellite launched for a geosynchronous orbit but unfortunately lost during orbit injection 8313. Syncom I 8314. Telstar I 8315. Sputnik I 8316. Early Bird I 8317. When the elevation angle of a geostationary satellite is 23˚ and the transmitting frequency is 3840 MHz, what is the free space loss in dB? 8318. 196 dB 8319. 200 dB 8320. 150 dB 8321. 100 dB 8322. What is the propagation delay when a signal is transmitter by an earth station to a geosynchronous satellite about 38,500 km above earth’s equator and then received by the same earth station? 8323. 256 msec 8324. 128 msec 8325. 300 msec 8326. 400 msec 8327. What is the free space attenuation of a satellite communications system operating at 36,000 km above the earth at 5.0 GHz? 8328. 198 dB 8329. 202 dB 8330. 142 dB 8331. 138 dB 8332. Which of the following is the most common application of satellite? 8333. Surveillance 8334. Military application 8335. Communications 8336. Newscasting 8337. Descending pass for a satellite means a pass from 8338. North to South 8339. South to North 8340. East to West 8341. West to East 8342. Geostationary stationary satellites are located ______with respect to the equator. 8343. 0˚longitude 8344. 0˚ latitude 8345. 90˚latitude 8346. 45 latitude˚ 8347. 8348. 8349. 8350. 8351. 8352. 8353. 8354. 8355. 8356. 8357. 8358. 8359. 8360. 8361. 8362. 8363. 8364. 8365. 8366. 8367. 8368. 8369. 8370. 8371. 8372. 8373. 8374. 8375. 8376. 8377. 8378. 8379. 8380. 8381. 8382. 8383. 8384. 3001 Questions in Communications Engineering – EXCEL REVIEW CENTER 8385. Chapter 6 - Antennas 8386. 8387. 1. What is the polarization of a discone antenna? 8388. A. Vertical 8389. B. Horizontal 8390. C. Circular 8391. D. Spiral 8392. 8393. 2. If the antenna increases 3.3 times how much does the radiated power increase? 8394. A. 3.3 times 8395. B. 10.89 times 8396. C. 9.9 times 8397. D. 6.6 times 8398. 8399. 3. When speaking of antennas. ______is a section which would be a complete antenna by itself. 8400. A. image 8401. B. top loading 8402. C. bay 8403. D. quarterwave 8404. 8405. 4. In what range of frequencies are most omnidirectional horizontally polarized antennas used? 8406. A. VHF, UHF 8407. B. VLF, LF 8408. C. SH, EHF 8409. D. MF, HF 8410. 8411. 5. If the current ratios of the two or more elements must be held 5% and the phase angle to 3° the antenna is called a 8412. A. end fire array 8413. B. critical phased array 8414. C. broadband array 8415. D. wideband array 8416. 8417. 6. A device that converts high frequency current into electromagnetic wave. 8418. A. Antenna 8419. B. Loudspeaker 8420. C. Microphone 8421. D. Transducer 8422. 8423. 7. Which is a non-resonant antenna? 8424. A. Rhombic antenna 8425. B. Folded dipole 8426. C. End-fire array 8427. D. Yagi-Uda antenna 8428. 8429. 8. Gain of a half-wave dipole antenna over isotropic. 8430. A. 2.15 dB 8431. B. 1.76 dB 8432. C. 1 dB 8433. D. 0dB 8434. 8435. 9. Very low signal strength in antenna. 8436. A. Minor lobes 8437. B. Null 8438. C. Antenna patterns 8439. D. Major lobes 8440. 8441. 10. What is the gain of the Hertzian dipole over isotropic antenna? 8442. A. 1.64 dB 8443. B. 2.15 dB 8444. C. 1.76 dB 8445. D. 1.55 dB 8446. 8447. 11. ______is the measurement of a unilateral antenna properties of directivity 8448. A. Phase angle 8449. B. Antenna gain 8450. C. Beamwidth 8451. D. Bandwidth 8452. 8453. 12. In testing transmitter to prevent interfering with other stations, which type of antenna must be used? 8454. A. Void antenna 8455. B. Dummy antenna 8456. C. Hertzian antenna 8457. D. Isotropic antenna 8458. 8459. 13. The best solution to fading is _____. 8460. A. space diversity 8461. B. frequency diversity 8462. C. polarization diversity 8463. D. wavelength diversity 8464. 8465. 14. _____ is the amount of uncertainty in a system of symbols 8466. A. Bandwidth 8467. B. Enthalpy 8468. C. Entropy 8469. D. Quantum 8470. 8471. 8472. 8473. 8474. 15. If an antenna has a gain of 3 dB, it increases the output of the transmitter by 8475. A. 10,000 times 8476. B. 1000 times 8477. C. 100 times 8478. D. 1 million times 8479. 8480. 16. Top loading is used in an antenna in order to increase its ______. 8481. A. practical height 8482. B. beamwidth 8483. C. effective height 8484. D. input capacitance 8485. 8486. 17. A horizontal antenna is _____. 8487. A. vertically polarized 8488. B. horizontally polarized 8489. C. centrally polarized 8490. D. circularly polarized 8491. 8492. 18. All elements in a beam _____ antennas are in line 8493. A. collinear 8494. B. yagi 8495. C. broadside array 8496. D. log-periodic 8497. 8498. 19. Which does not use vertical polarization antenna? 8499. A. AM Broadcasting 8500. B. FM Broadcasting 8501. C. Mobile Communications 8502. D. Satellite Communications 8503. 8504. 20. Lightning rods must be mounted a top structure not less than ___ above the highest point. 8505. A. 10 cm 8506. B. 20 cm 8507. C. 30 cm 8508. D. 40 cm 8509. 8510. 21. _____ is an antenna with a number of half-wave antenna on it. 8511. A. Antenna array 8512. B. Tower 8513. C. Omni-directional 8514. D. Rhombic 8515. 8516. 8517. 8518. 8519. 22. Which antenna radiates an omnidirectional pattern in the horizontal plane with vertical polarization? 8520. A. Marconi antenna 8521. B. Discone antenna 8522. C. Horn antenna 8523. D. Helical antenna 8524. 8525. 23. An antenna with very high gain and very narrow beamwidth. 8526. A. Helical antenna 8527. B. Discone antenna 8528. C. Horn antenna 8529. D. Parabolic dish antenna 8530. 8531. 24. What determines antenna polarization? 8532. A. The frequency of the radiated wave 8533. B. The direction of the radiated wave 8534. C. The direction of the magnetic field vector 8535. D. The direction of the electric field vector 8536. 8537. 25. _____ is the horizontal pointing angle of an antenna 8538. A. Azimuth 8539. B. Angle of elevation 8540. C. Right angle 8541. D. Beamwidth 8542. 8543. 26. A dipole antenna requires to be fed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11kW. What is the gain in dB, obtained by the use if the reflector. (Gain referred to this particular dipole). 8544. A. 4.75 8545. B. 2.6 8546. C. 1.81 8547. D. 4.24 8548. 8549. 27. What is the estimated medium wind loading in the Philippines for antenna tower design? 8550. A. 300 kph 8551. B. 100 kph 8552. C. 200 kph 8553. D. 250 kph 8554. 8555. 28. Discone radiation pattern is ______. 8556. A. omnidirectional/vertical polarized 8557. B. unidirectional 8558. C. bidirectional 8559. D. figure of eight 8560. 8561. 29. _____ is an open-ended slot antenna 8562. A. Helical antenna 8563. B. Rhombic antenna 8564. C. Notch antenna 8565. D. Cassegrain antenna 8566. 8567. 30. Which antenna is a properly terminated? 8568. A. Marconi 8569. B. Rhombic 8570. C. Dipole 8571. D. Yagi-Uda 8572. 8573. 31. What is the radiation characteristic of a dipole antenna? 8574. A. Omnidirectional 8575. B. Bidirectional 8576. C. Unidirectional 8577. D. Hemispherical 8578. 8579. 32. What is the theoretical gain of a Hertzian dipole? 8580. A. 1.76 dB 8581. B. 2.15 dB 8582. C. 3 dB 8583. D. 0 dB 8584. 8585. 33. An antenna with unity gain 8586. A. Rhombic 8587. B. Half-wave dipole 8588. C. Isotropic 8589. D. Whip 8590. 8591. 34. How will you increase the gain of an antenna? 8592. A. By adding several antennas in parallel 8593. B. By focusing the radiated energy in one desired direction 8594. C. By making antenna rods thicker 8595. D. By making the antenna size larger 8596. 8597. 35. An antenna which is one-tenth wavelength long 8598. A. Hertzian dipole 8599. B. Loop antenna 8600. C. Marconi antenna 8601. D. Elementary doublet 8602. 8603. 8604. 8605. 8606. 8607. 36. What is the minimum number of turns a helix antenna must have? 8608. A. 3 8609. B. 5 8610. C. 4 8611. D. 6 8612. 8613. 37. What is the gain of isotropic antenna? 8614. A. 10 8615. B. 1 8616. C. 10 8617. D. 100 8618. 8619. 38. Which of the following improves antenna directivity? 8620. A. Driven element 8621. B. Reflector element 8622. C. Director element 8623. D. Parasitic element 8624. 8625. 39. The antenna radiates _____ polarized waves when the transmitter antenna is horizontally installed. 8626. A. Vertically 8627. B. negatively 8628. C. horizontally 8629. D. circularly 8630. 8631. 40. The length of a Marconi antenna to operate with 985 kHz is ______. 8632. A. 200 ft 8633. B. 500 ft 8634. C. 250 ft 8635. D. 999 ft 8636. 8637. 41. What is the front-to-back ratio of an antenna which radiates 500 watts in a northernly direction and 50 watts in a southernly direction? 8638. A. 25000 dB 8639. B. 10 dB 8640. C. 100 dB 8641. D. 20 dB 8642. 8643. 42. If 4 kW in antenna produces 50 μV/m in a receiving antenna, a 15 kW will produce _____. 8644. A. 200 μV/m 8645. B. 10 μV/m 8646. C. 100 μV/m 8647. D. 20 μV/m 8648. 8649. 8650. 8651. 43. If the radiated power increase 10.89 times, the antenna current increases by ______. 8652. A. 3.3 times 8653. B. 6.6 times 8654. C. 1.82 times 8655. D. 10.89 times 8656. 8657. 44. The frequency of operation of a dipole antenna cut to a length of 3.4 m. 8658. A. 88 MHz 8659. B. 44 MHz 8660. C. 22 MHz 8661. D. 11 MHz 8662. 8663. 45. Comparing the signal strength arriving at the driven element from the desired direction to the signal strength reaching the driver from the opposite direction. 8664. A. Directivity 8665. B. Sensitivity 8666. C. Beamwidth 8667. D. Front-to-back ratio 8668. 8669. 46. What is the capture area of a dipole operated at 75 MHz? 8670. A. 4 mm 8671. B. 2 m2 8672. C. 2.088 m2 8673. D. 4.088 m2 8674. 8675. 47. _____ of an antenna is a measure of how the antenna concentrates its radiated power in a given direction. 8676. A. Efficiency 8677. B. Power 8678. C. Gain 8679. D. Polarization 8680. 8681. 48. Shortening effect of an antenna that makes it appear as if it were 5% longer. 8682. A. End effect 8683. B. Flywheel effect 8684. C. Skin effect 8685. D. Capture effect 8686. 8687. 49. Harmonic suppressor connected to an antenna. 8688. A. Low-pass filter 8689. B. High-pass filter 8690. C. M-derived filter 8691. D. Constant-K 8692. 8693. 8694. 8695. 50. A simple half-wavelength antenna radiates the strongest signal 8696. A. at 45 degrees to its axis 8697. B. parallel to its axis 8698. C. at right angles to its axis 8699. D. at 60 degrees to its axis 8700. 8701. 51. The current maximum in a Marconi antenna is found at 8702. A. the base of the antenna 8703. B. the center of the antenna 8704. C. some point between the base and the center of the antenna 8705. D. the top of the antenna 8706. 8707. 52. If an antenna is too short for the wavelength being used, the effective length can be increased by adding: 8708. A. capacitance in series 8709. B. inductance in series 8710. C. resistance in parallel 8711. D. resistance in series 8712. 8713. 53. Which of the following antennas is used for testing and adjusting a transmitter for proper modulation, amplifier operation and frequency accuracy? 8714. A. Elementary 8715. B. Real 8716. C. Isotropic 8717. D. Dummy 8718. 8719. 54. The power fed to a two-bay turnstile antenna is 100 watts. If the antenna has a 2 dB power gain, what is the effective radiated power? 8720. A. 317 watts 8721. B. 158 watts 8722. C. 200 watts 8723. D. 400 watts 8724. 8725. 55. What is the gain, in dB of a helical antenna with diameter of λ/3, 10 turns at pitch of λ/4, used at 100 MHz? 8726. A. 16 8727. B. 41.1 8728. C. 31.4 8729. D. 1.25 8730. 8731. 56. How is it possible to lower the resonant frequency of Hertz dipole antenna? 8732. A. By reducing the frequency at the transmitter 8733. B. By connecting a capacitor in series with the antenna 8734. C. By the connecting a resistor in series with the antenna 8735. D. By connecting an inductor in series with the antenna 8736. 8737. 57. Which of the following antennas receive signals in the horizontal plane equality well from all directions? 8738. A. Horizontal Hertz antenna 8739. B. Vertical loop antenna 8740. C. Vertical Yagi antenna 8741. D. A vertical antenna which is a quarter-wavelength long 8742. 8743. 58. If the length of a Hertz dipole is decreased 8744. A. its resonant frequency will be lowered its distributed inductance will be increased 8745. B. its distributed inductance will be decreased 8746. C. its resonant frequency will be increased 8747. D. its distributed capacitance between the antenna and ground will be increased. 8748. 8749. 59. A final amplifier of a radio transmitter draws 250 mA of plate current when the plate supply voltage is 1400 volts. If the plate circuit efficiency is 80% and the transmitter is connected to an antenna having a feed impedance of 70 ohms, what is the antenna current at the feed-point? 8750. A. 4.0 A 8751. B. 2.2 A 8752. C. 1.25 A 8753. D. 2.0 A 8754. 8755. 60. A one-quarter wavelength shunt-fed vertical Marconi antenna 8756. A. has maximum radiation in a vertical direction 8757. B. must have a horizontal receiving antenna for the best reception 8758. C. must use a receiving antenna for the best reception 8759. D. must have a vertical receiving antenna for the best reception 8760. 8761. 61. A shunt-fed quarter-wavelength Marconi antenna 8762. A. has maximum RF impedance to ground at its feedpoint 8763. B. has a current null at its feedpoint 8764. C. has a zero DC resistance to ground 8765. D. has zero RF resistance to ground 8766. 8767. 62. The parasitic element of an antenna system will 8768. A. decrease its directivity 8769. B. increase its directivity 8770. C. give the antenna unidirectional properties 8771. D. both B and C 8772. 8773. 63. If the length of an antenna is changed from 2.5 meters to 2.8 meters, its resonant frequency will 8774. A. increase 8775. B. depend on the velocity factor so the resonant frequency can either be increased or decreased 8776. C. will be unchanged 8777. D. decrease 8778. 64. What is the effect of adding a capacitor in series with an antenna? 8779. A. The antenna’s resonant frequency will increase 8780. B. The antenna’s resonant frequency will decrease 8781. C. The antenna will be physically 5% longer than its electrical length 8782. D. A capacitor is never added in series with an antenna 8783. 8784. 65. How does the electric field strength of a standard broadcast station vary with the distance from the antenna? 8785. A. The field strength of a standard broadcast station vary with the distance from the antenna 8786. B. The field strength is directly proportional to the distance from the antenna 8787. C. The field strength remains constant regardless of the distance from the antenna 8788. D. The field strength varies inversely as the distance from the antenna 8789. 8790. 66. Stacking elements in a transmitting antenna system 8791. A. increases the field strength at the receiving antenna 8792. B. increases the directivity of the transmitter antenna 8793. C. decrease the size of the lobe in the radiation pattern 8794. D. both A and B 8795. 8796. 67. A vertical loop antenna has a 8797. A. unidirectional radiation pattern in the horizontal plane 8798. B. unidirectional radiation pattern in the vertical plane 8799. C. omnidirectional radiation pattern in the horizontal plane 8800. D. a bidirectional radiation pattern in the horizontal plane 8801. 8802. 68. In order to get maximum radiation to all surrounding points in the horizontal plane, the antenna used is a 8803. A. vertical loop 8804. B. vertical quarter-wavelength rod 8805. C. array which includes parasitic elements 8806. D. a horizontal Hertz dipole 8807. 8808. 69. What is the electrical wavelength of a 500 MHz signal? 8809. A. 60 centimeters 8810. B. 6 meters 8811. C. 0.06 meter 8812. D. 60 meters 8813. 8814. 70. If the antenna current is doubled, the field strength at a particular position is 8815. A. doubled 8816. B. halved 8817. C. multiplied by a factor of four 8818. D. divided by a factor of four 8819. 8820. 8821. 71. The rhombic antenna is primarily used for 8822. A. ground wave propagation 8823. B. space wave propagation 8824. C. ionosphere scatter propagation 8825. D. sky wave propagation 8826. 8827. 72. What antenna radiates equally in all directions? 8828. A. Vertical antenna 8829. B. isotropic antenna 8830. C. Horizontal antenna 8831. D. Dipole antenna 8832. 8833. 73. Actual height of antenna should be at least 8834. A. one wavelength 8835. B. half wavelength 8836. C. quarter wavelength 8837. D. three-fourth wavelength 8838. 8839. 74. Which antenna is not properly terminated? 8840. A. Resonant 8841. B. Non-resonant 8842. C. Isotropic 8843. D. Whip 8844. 8845. 75. ______is an antenna array which is highly directional at right angles to the plane of the array? 8846. A. Broadside array 8847. B. End-fire array 8848. C. Turnstile array 8849. D. Log-periodic array 8850. 8851. 76. The directivity pattern of an isotropic radiator is 8852. A. a figure-8 8853. B. a sphere 8854. C. a unidirectional cardioid 8855. D. a parabola 8856. 8857. 77. An isotropic radiator is 8858. A. in the northern hemisphere 8859. B. an antenna high enough in the air 8860. C. an antenna whose directive pattern is substantially incredible 8861. D. a hypothetical, omnidirectional antenna 8862. 8863. 8864. 8865. 8866. 78. The purpose of stacking elements on an antenna. 8867. A. Sharper directional pattern 8868. B. increased gain 8869. C. Improved bandpass 8870. D. All of these 8871. 8872. 79. The advantage of using top loading in a shortened HF vertical antenna is 8873. A. lower quality factor 8874. B. greater structural strength 8875. C. higher losses 8876. D. improved radiation efficiency 8877. 8878. 80. Where are the voltage nodes in a half-wave antenna? 8879. A. At the ends 8880. B. Three-quarters of the way from the feed point toward the end 8881. C. One-half of the way from the feed point toward the end 8882. D. At the feed point 8883. 8884. 81. A theoretical reference antenna that provides a comparison for antenna measurements. 8885. A. Marconi antenna 8886. B. Isotropic radiator 8887. C. Yagi-Uda array 8888. D. Whip antenna 8889. 8890. 82. A Hertz antenna is operating on a frequency of 2182 kHz and consists of a horizontal wire that is hanged between two towers. What is the frequency of its third harmonic? 8891. A. 727 kHz 8892. B. 6546 kHz 8893. C. 436 kHz 8894. D. 6.546 kHz 8895. 8896. 83. In horizontal-dipole antenna, the polarization is 8897. A. in the vertical direction 8898. B. in the horizontal direction 8899. C. circular 8900. D. measured at the center of the antenna 8901. 8902. 84. Increasing the electrical length of an antenna means 8903. A. add an inductor in parallel 8904. B. add a capacitor in series 8905. C. add an inductor series 8906. D. add a resistor is series 8907. 8908. 8909. 8910. 8911. 85. Stacking antennas at various angles results in 8912. A. a more omnidirectional reception 8913. B. a more unidirectional reception 8914. C. a more omnidirectional reception 8915. D. an overall reception signal increase 8916. 8917. 86. What is driven element? 8918. A. Always the rearmost element 8919. B. Always the forward most element 8920. C. The element fed by the transmission line 8921. D. The element connected to the rotator 8922. 8923. 87. What is antenna bandwidth? 8924. A. Antenna length divided by the number of elements 8925. B. The angle between the half-power radiation points 8926. C. The angle formed between two imaginary lines drawn through 8927. D. The frequency range over which an antenna can be expected to operate satisfactorily 8928. 8929. 88. To lengthen an antenna electrically, add a 8930. A. resistor 8931. B. battery 8932. C. condult 8933. D. coil 8934. 8935. 89. What is the gain of an antenna over a half-wavelength dipole when it has 6 dB gain over an isotropic radiator? 8936. A. 6.0 dB 8937. B. 8.1 dB 8938. C. 3.9 dB 8939. D. 10.0 dB 8940. 8941. 90. What is the usual electrical length of a driven element in an HF beam antenna? 8942. A. ¼ wavelength 8943. B. ¾ wavelength 8944. C. ½ wavelength 8945. D. 1 wavelength 8946. 8947. 91. What happens to the bandwidth of an antenna as it is shortened through the use of loading coils? 8948. A. It is increased 8949. B. It is decreased 8950. C. No change occurs 8951. D. It becomes flat 8952. 8953. 8954. 8955. 92. To electrically decrease the length of an antenna. 8956. A. add an inductor in series 8957. B. add an inductor in parallel 8958. C. add a resistor in series 8959. D. add a capacitor in series 8960. 8961. 93. Strong interference from one particular station can be eliminated by the use of 8962. A. noise limiters 8963. B. squelch circuits 8964. C. negative feedback 8965. D. wave traps in the antenna circuitry 8966. 8967. 94. It is useful to refer to an isotropic radiator. 8968. A. when comparing the gains of directional antennas 8969. B. when testing a transmission line for standing wave ratio 8970. C. when (in the northern hemisphere) directing the transmission 8971. D. when using a dummy load to tune a transmitter 8972. 8973. 95. A disadvantage of using a trap antenna. 8974. A. It will radiate harmonics 8975. B. It can only be used for single-bad operation 8976. C. It is too sharply directional at lower frequencies 8977. D. It must be neutralized 8978. 8979. 96. The input terminal impedance at the center of a folded dipole antenna is 8980. A. 72 Ω 8981. B. 300 Ω 8982. C. 50 Ω 8983. D. 73 Ω 8984. 8985. 97. When a capacitor is connected in series with a Marconi antenna? 8986. A. Antenna open circuit stops transmission 8987. B. An inductor of equal value must be added 8988. C. No change occurs to antenna 8989. D. Antenna resonant frequency increases 8990. 8991. 98. Where are the current nodes in a half-wave antenna? 8992. A. At the ends 8993. B. At the center 8994. C. Three-quarters of the way from the feed point toward the end 8995. D. One-half of the way from the feed point toward the end 8996. 8997. 8998. 8999. 9000. 99. For a shortened vertical antenna, where should a loading coil be placed to minimize losses and produce the most effective performance? 9001. A. As low as possible on the vertical radiator 9002. B. Near the center of the vertical radiator 9003. C. As close to the transmitter as possible 9004. D. At a voltage node 9005. 9006. 100. The effect of adding parasitic elements of a Hertz dipole is to 9007. A. make the antenna more omnidirectional 9008. B. reduce its resonant frequency 9009. C. increase the antenna’s power gain 9010. D. All of these 9011. 9012. 101. Stacking antenna elements 9013. A. increases sensitivity to weak signals 9014. B. will suppress odd harmonics 9015. C. decrease signal to noise ratio 9016. D. increases selectivity 9017. 9018. 102. In the case if Marconi antenna, the actual length if the radiating element is 9019. A. one-half wavelength 9020. B. one-quarter wavelength 9021. C. one wavelength 9022. D. one-eight wavelength 9023. 9024. 103. The antenna efficiency of an HF grounded vertical antenna can be made comparable to that of a half-wave antenna 9025. A. By installing a good ground radial system 9026. B. By isolating the coax shield from ground 9027. C. By shortening the vertical 9028. D. By lengthening the vertical 9029. 9030. 104. An antenna “efficiency” is computed by using one of the following equations. 9031. A. Efficiency = (radiation resistance / transmission resistance) 9032. B. Efficiency = (total resistance / radiation resistance) x 100% 9033. C. Efficiency = (effective radiated power / transmitter output) x 100% 9034. D. Efficiency = (radiation resistance / total resistance) x 100% 9035. 9036. 105. Increasing the resonant frequency of an end-fed Marconi antenna can be done by 9037. A. adding a capacitor in series and reducing the physical length 9038. B. adding an inductor in series 9039. C. adding an inductor in series 9040. D. All of these 9041. 9042. 9043. 9044. 106. Factors that determine the radiation resistance of an antenna 9045. A. Transmission line length and height of antenna 9046. B. The location of the antenna with respect to nearby objects 9047. C. It is a constant for all antennas since it is physical 9048. D. Sunspot activity and the time of day 9049. 9050. 107. _____ is the angle between the half-power radiation points 9051. A. Critical angle 9052. B. Beamwidth 9053. C. Angle of elevation 9054. D. Azimuth 9055. 9056. 108. What is the ratio of the maximum radiation intensity to the average radiation intensity? 9057. A. Aperture gain 9058. B. Directivity gain 9059. C. Transmission gain 9060. D. Power gain 9061. 9062. 109. Good grounding is important for 9063. A. horizontal antennas 9064. B. broadside array antennas 9065. C. vertical antennas 9066. D. Yagi-Uda antennas 9067. 9068. 110. An ungrounded antenna near the ground 9069. A. acts as a single antenna of twice the height 9070. B. is unlikely to need an earth mat 9071. C. acts as antenna array 9072. D. must be horizontally polarized 9073. 9074. 111. One of the following is very useful as a multiband HF receiving antenna. 9075. A. Parabolic antenna 9076. B. Elementary doublet 9077. C. Log-periodic 9078. D. Square loop 9079. 9080. 112. Which of the following antennas is best excited from a waveguide? 9081. A. Biconical 9082. B. Horn 9083. C. Helical 9084. D. Discone 9085. 9086. 9087. 9088. 9089. 9090. 113. Indicate which of the following reasons for using metal counterpoise with antennas is false. 9091. A. Impossibly of a good ground connection 9092. B. Protection of personnel working underneath 9093. C. Provision of an earth for the antenna 9094. D. Rockiness of the ground itself 9095. 9096. 114. Not a reason for the use of an antenna coupler. 9097. A. To make the antenna look resistive 9098. B. To provide the output amplifier with the correct load impedance 9099. C. To discriminate against harmonics 9100. D. To prevent re-radiation of the local oscillator 9101. 9102. 115. Which antenna is not a wideband? 9103. A. Discone 9104. B. Folded dipole 9105. C. Helical 9106. D. Marconi 9107. 9108. 116. One of the following is not a reason for the use of an earth mat 9109. A. impossibility of a good ground connection 9110. B. provision of an earth for the antenna 9111. C. protection of personnel working underneath 9112. D. improvement of the radiation pattern of the antenna 9113. 9114. 117. One of the following makes an antenna physically long but electrically short 9115. A. Adding L in series 9116. B. Adding C in series 9117. C. Top loading 9118. D. Both A and C 9119. 9120. 118. When antennas are closed to the ground, ______polarization is ideal 9121. A. horizontally polarized 9122. B. vertically polarized 9123. C. circularly polarized 9124. D. both A and B 9125. 9126. 119. _____ is an antenna made up of a number of full wavelengths 9127. A. Elementary doublet 9128. B. Log-periodic 9129. C. Long wire 9130. D. Whip 9131. 9132. 9133. 9134. 9135. 120. Any energy which radiates in the form of radio waves, infrared waves, light waves, x-rays, etc. 9136. A. Radiant energy 9137. B. Electromagnetic 9138. C. Heat 9139. D. Ultraviolet 9140. 9141. 121. Which one is an antenna coupling unit? 9142. A. Coupler 9143. B. Diplexer 9144. C. Lecher wire 9145. D. Duplexer 9146. 9147. 122. _____ polarization is employed in AM broadcasting 9148. A. Horizontal 9149. B. Vertical 9150. C. Circular 9151. D. Omnidirectional 9152. 9153. 123. ______polarization is employed in FM broadcasting 9154. A. Horizontal 9155. B. Vertical 9156. C. Circular 9157. D. Bidirectional 9158. 9159. 124. Which antenna is not grounded at one end? 9160. A. Hertz 9161. B. Marconi 9162. C. Dipole 9163. D. Whip 9164. 9165. 125. Which antenna does not use the ground? 9166. A. Marconi 9167. B. Yagi 9168. C. Hertz 9169. D. Rhombic 9170. 9171. 9172. 9173. 9174. 9175. 9176. 9177. 9178.

9179. OPTICAL FIBER COMMUNICATIONS

9180. Founded the wave theory of light

9181. Francesco Grimaldi

9182. Edward Appleton

9183. James Clerk Maxwell

9184. Christian Huygens

9185.

9186. Proposed the use of clad glass fiber as a dielectric waveguide

9187. Karpon and Keck

9188. Karpon and Bockham

9189. Bockham and Kao

9190. Kao and Keck

9191.

9192. Developed the first laser

9193. Charles Townes

9194. Theodore Maiman

9195. Gordon McKenzie

9196. Albert Einstein

9197.

9198. The band of light wavelengths that are too long to be seen by the human eye 9199. Amber

9200. Visible

9201. Infrared

9202. Ultraviolet

9203.

9204. The band of light wavelengths that are too short to be seen by the human eye

9205. Amber

9206. Visible

9207. Infrared

9208. Ultraviolet

9209.

9210. Which color has the shortest wavelength of light?

9211. Red

9212. Yellow

9213. Blue

9214. Green

9215.

9216. What generates a light beam of a specific visible frequency?

9217. Laser

9218. Maser

9219. Infrared

9220. Flashlight

9221. 9222. Which of the following materials is sensitive to light?

9223. Photoresist

9224. Photosensitive

9225. Light Sensitive

9226. Maser

9227.

9228. The core of an optical fiber has a

9229. Lower refracted index than air

9230. Lower refractive index than the cladding

9231. Higher refractive index than the cladding

9232. Similar refractive index with the cladding

9233.

9234. Is the different angle of entry of light into an optical fiber when the diameter of the core is many times the wavelength of the light transmitted.

9235. Acceptance angle

9236. Modes

9237. Sensors

9238. Aperture

9239.

9240. The loss in signal power as light travels down a fiber is called

9241. Dispersion

9242. Scattering

9243. Absorption

9244. Attenuation 9245.

9246. The bandwidth of optical fiber

9247. 900MHz

9248. 900PHz

9249. 900THz

9250. 900EHz

9251.

9252. If a mirror is used to reflect light, the reflected light angle is ____ as the incident angle

9253. Smaller

9254. Larger

9255. The same

9256. Independent

9257.

9258.

9259.

9260. What is a specific path the light takes in an optical fiber corresponding to a certain angle and number of reflection

9261. Mode

9262. Grade

9263. Numerical Aperture

9264. Dispersion

9265.

9266. 9267.

9268. Is the width of the range of wavelengths emitted by the light source

9269. Bandwidth

9270. Chromatic Dispersion

9271. Spectral width

9272. Beamwidth

9273.

9274. Which theory states that the light wave behaves as if it consists of many tiny particles?

9275. Huygen’s theory

9276. Wave theory of light

9277. Nyquist theory

9278. Quantum theory

9279.

9280. Fiber optic cables operate at frequencies near

9281. 20MHz

9282. 200MHz

9283. 2GHz

9284. 800THz

9285.

9286. When a beam of light enters one medium from another, which quantity will not change?

9287. Direction

9288. Speed 9289. Frequency

9290. Wavelength

9291.

9292. Dispersion is used to describe the

9293. Splitting of white light into its component colors

9294. Propagation of light in straight lines

9295. Bending of a beam of light when it goes from one medium to another

9296. Bending of a beam light when it strikes a mirror

9297.

9298. Luminance efficiency is minimum for a

9299. Fluorescent tube

9300. High wattage light bulb

9301. Mercury vapor lamp

9302. Low wattage light bulb

9303.

9304. An object farther from a converging lens than its focal point always has a/an _____ image.

9305. Inverted

9306. The same in size

9307. Virtual

9308. Smaller size

9309.

9310. An object nearer to a converging lens than its focal point always has a/an ______image. 9311. Inverted

9312. The same in size

9313. Virtual

9314. Smaller size

9315.

9316. The real image formed by a spherical mirror is ____ relative to its object

9317. Erect

9318. Inverted

9319. Smaller

9320. Larger

9321.

9322.

9323. The wavelength of light has no role in

9324. Diffraction

9325. Interference

9326. Polarization

9327. Reflection

9328.

9329. Longitudinal waves do not exhibit

9330. Polarization

9331. Refraction

9332. Reflection

9333. Diffraction 9334.

9335. ______dispersion is caused by the difference in the propagation times of light rays that take different paths down a fiber.

9336. Material dispersion

9337. Wavelength dispersion

9338. Modal dispersion

9339. Delay dispersion

9340.

9341. What is the average insertion loss of fusion splice in fiber optics?

9342. 0.09dB

9343. 0.9dB

9344. 0.19dB

9345. 0.009dB

9346.

9347. What is the insertion loss of connector-type splices for a single mode fiber optics?

9348. 0.51dB

9349. 0.31dB

9350. 0.49dB

9351. 0.38dB

9352.

9353. What is the lifetime of LEDs?

9354. 200,000 minutes

9355. 200,000 hours

9356. 150,000 minutes 9357. 150,000 hours

9358.

9359. What is the lifetime of ILDs?

9360. 50,000 hours

9361. 75,000 hours

9362. 100,000 hours

9363. 125,000 hours

9364. 9365. Photodiodes used as fiber optic directors are 9366. Unbiased to generate a voltage same as a solar cell 9367. Forward bias 9368. Reversed bias 9369. Thermoelectrically cooled 9370. 9371. 9372. What type of fiber has the highest modal dispersion? 9373. Step-index multimode 9374. Graded index multimode 9375. Step-index single mode 9376. Graded index mode 9377. 9378. 9379. Laser light is ______emission. 9380. Coherent 9381. Stimulated 9382. Spontaneous 9383. Coherent and stimulated 9384. 9385. 9386. A dielectric waveguide for the propagation of electromagnetic energy at light frequencies 9387. Stripline 9388. Microstrip 9389. Laser beam 9390. Fiber optics 9391. 9392. 9393. Is a non-coherent light source foe optical communications system. 9394. ILD 9395. LED 9396. APD 9397. PIN Diode 9398. 9399. 9400. Which type of laser is the simplest to modulate directly by changing its excitation? 9401. Semiconductor 9402. Ruby 9403. Helium-neon 9404. Neodymium-YAG 9405. 9406. 9407. Which laser emits light in the visible range 400 to 700 nm? 9408. Argon-ion 9409. Nitrogen 9410. Carbon-dioxide 9411. Neodymium-YAG 9412. 9413. 9414. Which is the proper measurement of average power emitted by a pulsed laser? 9415. Energy x time 9416. Pulse energy x repetition rate 9417. Pulse energy / repetition rate 9418. Peak power x pulse length 9419. 9420. 9421. What is the photon energy for an infrared wave with frequency of 1012 Hz? 9422. 10.6 x 1034 joules 9423. 6.63 x 10-34 joules 9424. 6.63 x 10-22 joules 9425. 10.6 x 1022 joules 9426. 9427. 9428. A positive lens with a focal length of 10 cm forms a real image of an object 20 am away from the lens. How far is the real image from the lens? 9429. 5 cm 9430. 10 cm 9431. 15 cm 9432. 20 cm 9433. 9434. 9435. Which of the following factor does not harm laser efficiency? 9436. Atmospheric absorption 9437. Excitation energy not absorbed 9438. Problems in depopulating the lower laser level 9439. Inefficiency in populating the upper laser level 9440. 9441. 9442. Which of the following contributes to the broadening of laser emission bandwidth? 9443. Doppler shift of moving atoms and molecules 9444. Amplification within the laser medium 9445. Coherence of the laser light 9446. Optical pumping of the laser transition 9447. 9448. 9449. The first laser emitted 9450. Pulses of 694 nm red light 9451. A continuous red beam 9452. Pulses of white light from a helical flashlamp 9453. Spontaneous emission 9454. 9455. 9456. What is the stage of the sand becoming a silicon? 9457. Liquid 9458. Gas 9459. Molten 9460. Hot 9461. 9462. 9463. Which of the following is used as an optical transmitter on the Fiber Optical Communications? 9464. APD 9465. LSA diode 9466. PIN diode 9467. LED 9468. 9469. 9470. Which of the following is used as an optical receiver in fiber optics communications 9471. APD 9472. Tunnel diode 9473. Laser diode 9474. LED 9475. 9476. 9477. The numerical aperture of a fiber if the angle of acceptance is 15 degrees, is 9478. 017 9479. 0.26 9480. 0.50 9481. 0.75 9482. 9483. 9484. The inner portion of the fiber cable is called 9485. Cladding 9486. Coating 9487. Inner conductor 9488. Core 9489. 9490. 9491. Which type of laser is the simplest to modulate directly by changing its excitation? 9492. Semiconductor 9493. Ruby 9494. Helium-neon 9495. Neodymium-YAG 9496. 9497. 9498. The laser frequency when the light has the wavelength 800 nm is 9499. 375 x 10^12 Hz 9500. 475 x 10^15 Hz 9501. 375 x 10^9 Hz 9502. 375 x 10^18 Hz 9503. 9504. 9505. Which of the following is not a common application of fiber-optic cable? 9506. Computer networks 9507. Long-distance telephone systems 9508. Closed circuit TV 9509. Consumer TV 9510. 9511. 9512. Total internal reflection takes place if the light ray strikes the interface at an angle with what relationship to the critical angle? 9513. Less than 9514. Grater than 9515. Equal to 9516. Zero 9517. 9518. 9519. The operation of the fiber-optic cable is based on the principle of 9520. Refraction 9521. Reflection 9522. Dispersion 9523. Absorption 9524. 9525. 9526. Which of the following is not a common type of fiber-optic cable? 9527. Single-mode step-index 9528. Multimode graded-index 9529. Single-mode graded-index 9530. Multimode step-index 9531. 9532. Cable attenuation is usually expressed in terms of 9533. Loss per foot 9534. dB/km 9535. intensity per mile 9536. voltage drop per inch 9537. 9538. 9539. Which of the cable length has the highest attenuation? 9540. 1 km 9541. 2 km 9542. 95 ft 9543. 5500 ft 9544. 9545. 9546. The upper pulse rate and information carrying capacity of a cable is limited by 9547. Pulse shortening 9548. Attenuation 9549. Light leakage 9550. Modal dispersion 9551. 9552. 9553. The core of a fiber optic cable is made of 9554. Air 9555. Glass 9556. Diamond 9557. Quartz 9558. 9559. 9560. The core of a fiber optic is surrounded by 9561. Wire braid shield 9562. Kevlar 9563. Cladding 9564. Plastic insulation 9565. 9566. 9567. The speed of light in plastic compared to the speed of light in air is 9568. Slower 9569. Faster 9570. The same 9571. Either lower or faster 9572. 9573. 9574. Which of the following is not a major benefit of fiber-optic cable? 9575. Immunity from interference 9576. No electrical safety problems 9577. Excellent data security 9578. Lower cost 9579. 9580. 9581. The main benefit of light-wave communications over microwaves or any other communications media is 9582. Lower cost 9583. Better security 9584. Wider bandwidth 9585. Freedom from interference 9586. 9587. 9588. Which of the following is not part of the optical spectrum? 9589. Infrafed 9590. Ultraviolet 9591. Visible color 9592. X-rays 9593. 9594. 9595. The wavelength of visible light extends from 9596. 0.8 to 1.0 nm 9597. 400 to 750 nm 9598. 200 to 660 nm 9599. 700 to 1200 nm 9600. 9601. 9602. The speed of light is 9603. 186,000 mi/h 9604. 300 mi/h 9605. 300,000 m/s 9606. 300,000,000 m/s 9607. 9608. 9609. Refraction is the 9610. Bending of light waves 9611. Reflection of light waves 9612. Distortion of light waves 9613. Diffusion of light waves 9614. 9615. 9616. The ratio of speed of light in air to the speed of light in another substance is called the 9617. Speed factor 9618. Index of reflection 9619. Index of refraction 9620. Dielectric constant 9621. 9622. 9623. A popular light wavelength in fiber-optic cable is 9624. 0.7 um 9625. 1.3 um 9626. 1.5 um 9627. 1.8 um 9628. 9629. 9630. Which type of fiber optic cable is most widely used? 9631. Single-mode step-index 9632. Multimode step-index 9633. Single-mode graded-index 9634. Multimode graded-index 9635. 9636. 9637. Which type of fiber-optic cable is the best for very high speed data? 9638. Single-mode step-index 9639. Multimode step-index 9640. Single-mode graded-index 9641. Multimode graded-index 9642. 9643. 9644. Which type of fiber-optic cable has the least modal dispersion? 9645. Single mode step-index 9646. Multimode step-index 9647. Single-mode graded-index 9648. Multimode graded-index 9649. 9650. 9651. Which of the following is not a factor in cable light loss? 9652. Reflection 9653. Absorption 9654. Scattering 9655. Dispersion 9656. 9657. 9658. A distance of 8 km is the same as 9659. 2.5 mi 9660. 5 mi 9661. 8 mi 9662. 12.9 mi 9663. 9664. 9665. A fiber-optic cable has a loss of 15 dB/km. The attenuation in a cable, 100 ft long is 9666. 4.57 dB 9667. 9.3 dB 9668. 24 dB 9669. 49.2 dB 9670. 9671. 9672. Fiber-optic cables with attenuations of 1.8, 3.4, 5.9, and 18 dB are linked together. The total loss is 9673. 7.5 dB 9674. 19.8 dB 9675. 29.1 dB 9676. 650 dB 9677. 9678. 9679. Which light emitter is preferred for high speed data in a fiber-optic system 9680. Incandescent 9681. LED 9682. Neon 9683. Laser 9684. 9685. 9686. Most fiber-optic light sources emit light in which spectrum? 9687. Visible 9688. Infrared 9689. Ultraviolet 9690. X-ray 9691. 9692. 9693. Both LEDs and ILDs operate correctly with 9694. Forward bias 9695. Reverse bias 9696. Neither A or B 9697. Either A or B 9698. 9699. 9700. Single-frequency light is called 9701. Pure 9702. Intense 9703. Coherent 9704. Monochromatic 9705. 9706. 9707. Laser light is very bright because it is 9708. Pure 9709. White 9710. Coherent 9711. Monochromatic 9712. 9713. 9714. Which of the following is NOT a common light detector 9715. PIN photodiode 9716. Photovoltaic diode 9717. Photodiode 9718. Avalanche photodiode 9719. 9720. 9721. Which of the following is the fastest light sensor 9722. PIN photodiode 9723. Photovoltaic diode 9724. Phototransistor 9725. Avalanche photodiode 9726. 9727. 9728. Photodiodes operate property with 9729. Forward bias 9730. Reverse bias 9731. Neither A or B 9732. Either A or B 9733. 9734. 9735. The product of the bit rate and distance of a fiber-optic system is 2 Gbits km/s. What is the maximum rate at 5 km? 9736. 100 Mbits/s 9737. 200 Mbits/s 9738. 400 Mbits/s 9739. 1000 Gbits/s 9740. 9741. 9742. Which fiber-optic system is better? 9743. 3 repeaters 9744. 8 repeaters 9745. 11 repeaters 9746. 20 repeaters 9747. 9748. 9749. An important requirement for successful transmission system using light 9750. Powerful, reliable light source 9751. Strong glass 9752. Reliable, high cost transmission medium 9753. Powerful regenerators 9754. 9755. 9756. What is used to block light from a laser and let other light through 9757. Neutral density 9758. Color 9759. Interference 9760. Spatial 9761. 9762. 9763. ______is a light that can be coherent 9764. Spontaneous emission 9765. Monochromatic and in-phase 9766. Narrow beam divergence 9767. Monochromatic 9768. 9769. 9770. Coherence of laser light is important for ______9771. Light propagation 9772. Getting laser light to pass through air 9773. Drilling holes 9774. Holography 9775. 9776. 9777. The ultrapure glass used to manufacture optical fibers is approximately ___pure 9778. 99.9 % 9779. 99.99 % 9780. 99.999% 9781. 99.9999% 9782. 9783. 9784. In fiber optics, PCS stands for 9785. Plastic-clad-silica 9786. Polyethylene-clad-silica 9787. Personal carrier system 9788. Personal communication 9789. 9790. 9791. How many longitudinal modes can fall within a laser’s gain bandwidth? 9792. 2 9793. 5 9794. 9 9795. No fixed limit, dependent on bandwidth and mode spacing 9796. 9797. 9798. ______is the result of photons of light that are absorbed by the atoms of the glass core molecules 9799. Ion resonance absorption 9800. Ultraviolet absorption 9801. Infrared absorption 9802. Absorption loss 9803. 9804. 9805. In fiber optics, SCS stands for 9806. Suppressed-clad-silicon 9807. Silicon base-class-silica 9808. Silica-clad-silica 9809. Serial-clad-silicon 9810. 9811. 9812. Human laser was developed by A. Javen at Bell laboratory in 9813. 1960 9814. 1962 9815. 1963 9816. 1964 9817. 9818. 9819. What parameter of light detector determines the range or system length that can be achieved for a given wavelength? 9820. Transit time 9821. Spectral response 9822. Dark current 9823. Responsitivity 9824. 9825. 9826. Dark current in light detectors is caused by 9827. Thermally generated carriers in the diode 9828. The absence of light input 9829. Small leakage current 9830. Its imperfection 9831. 9832. 9833. What is the unit of responsitivity? 9834. Ampere/volt 9835. Ampere/watt 9836. Watt/ampere 9837. Volts/ampere 9838. 9839. 9840. One of the following is not a characteristic of light detectors. 9841. Responsitivity 9842. Spectral response 9843. Transmit time 9844. Dispersion 9845. 9846. 9847. What is the typical wavelength of light emitted from epitaxially grown LEDs? 9848. 840 nm 9849. 490 nm 9850. 480 nm 9851. 940 nm 9852. 9853. 9854. SONET stands for 9855. System Optical Network 9856. Synchronous Optical Network 9857. Silica Optic Network 9858. System Optical Fiber Net 9859. 9860. 9861. Band loss is 9862. A reduction in transmitter power caused by earth’s surface curvature 9863. A reduction in strength of the signal caused by folded dipole bends 9864. An attenuation increase caused by bends radiating from the side of the fiber 9865. All of these 9866. 9867. 9868. Infrared range for fiber optics 9869. 400 – 700 nm 9870. 700 – 1200 nm 9871. 300 – 2000 nm 9872. 400 – 7000 nm 9873. 9874. 9875. Which of the following is a disadvantage for plastic fiber optics? 9876. Noise immunity 9877. Electric hazards 9878. Higher losses 9879. All of these 9880. 9881. 9882. OTDR stands for 9883. Optical Time Domain Reflectometer 9884. Optical Transmit Direction Return 9885. Optical Time Domain Time Regeneration 9886. Overtime Direct Reference 9887. 9888. 9889. Which of the following is determined by an OTDR? 9890. Distance to trouble 9891. Length of fiber 9892. Refractive index 9893. All of these 9894. 9895. 9896. Under normal condition, a single fiber should not be used for a two-way communication mainly because of 9897. Loss 9898. Fading 9899. Noise 9900. Attenuation 9901. 9902. 9903. A single mode optical fiber has a core diameter of _____ nm. 9904. 0.1 9905. 0.01 9906. 0.2 9907. 0.05 9908. 9909. 9910. A step-index multimode optical fiber has a core diameter of _____ nm. 9911. 0.02 9912. 0.2 9913. 2 9914. 0.002 9915. 9916. 9917. The graded-index multimode optical fiber has a core diameter of _____ nm. 9918. 0.5 9919. 0.05 9920. 0.0005 9921. 5 9922. 9923. 9924. Which is not a possible cause of optical fiber loss? 9925. Impurities 9926. Glass attenuation 9927. Stepped index operation 9928. Microbending 9929. 9930. 9931. The ratio of the speed of light in a vacuum and the speed of light in the material used. 9932. S/N ratio 9933. Refractive index 9934. Intermodal dispersion 9935. Monomode ratio 9936. 9937. 9938. Splicing fibers means 9939. Fusion 9940. Butt 9941. Glue 9942. Both fusion and butt 9943. 9944. 9945. An IC that represents a short distance one-way optical communications 9946. Optoisolator 9947. Insulator 9948. Multivibrator 9949. Optical IC 9950. 9951. 9952. When light strikes a flat polished end of a fiber, it produces a loss of 9953. 14 % 9954. 4 % 9955. 10 % 9956. 1 % 9957. 9958. 9959. When light strikes a flat polished end of a fiber, the fiber loss produced can be reduced by 9960. Splicing 9961. Antireflection coating 9962. Insulation jacket 9963. All of these 9964. 9965. 9966. In fiber optics, higher-order mode refers to 9967. Cladding boundary at high angle 9968. Backscattering electromagnetic signals 9969. Diffracting signals 9970. All of these 9971. 9972. 9973. 9974. The following are the cause of light attenuation in fiber optics except 9975. Backscattering 9976. Absorption 9977. Refraction 9978. Microbends 9979. 9980. 9981. Why are visible-light LEDs not used for fiber optics? 9982. It has high losses 9983. It has short wave 9984. It has low attenuation 9985. It has weak signal 9986. 9987. 9988. Optical cable testers are used for 9989. Checking refractive index 9990. Light power out of a fiber 9991. Non-calibrated light into a fiber 9992. Checking maximum distance covered 9993. 9994. 9995. A function of an optic isolator 9996. Cancels reflective waves 9997. Amplifies signal transmitted 9998. Filters unnecessary signals 9999. All of these 10000. 10001. 10002. An increase in light intensity produces fast optic switching due to 10003. Increase in index of glass 10004. Amplification of optical signal 10005. High gain 10006. Photoconductivity 10007. 10008. 10009. Light traveling in optical fiber follows which of the following principles. 10010. Huygen’s principle 10011. Reflection theory 10012. Light theory 10013. Snell;s law 10014. 10015. 10016. Optical fibers for telecommunications are typically about _____ mils thick and consists of a glass core, a glass cladding of lower index of refraction, and a protective coating 10017. 5 10018. 6 10019. 7 10020. 8 10021. 10022. 10023. Material dispersion is caused by the 10024. Wavelength dependence of the index of refraction 10025. Wavelength independence of the index of refraction 10026. Dependence of the propagation constant on the mode number 10027. Independence of the propagation constant on the mode number 10028. 10029. 10030. Modal dispersion is caused by the 10031. Dependence of wavelength on index of refraction 10032. Dependence of propagation constant on index of refraction 10033. Dependence of the propagation constant on the wavelength 10034. Dependence of the propagation constant on the mode number 10035. 10036. 10037. The dominant loss mechanisms in silica fiber are 10038. Absorption and radiation losses 10039. Absorption and Rayleigh scattering 10040. Coupling and radiation losses 10041. Radiation and modal dispersion 10042. 10043. 10044. The bandwidth of a fiber is limited by 10045. Mode 10046. Wavelength 10047. Dispersion 10048. Frequency 10049. 10050. 10051. Fiber bandwidth is generally specified as the 10052. Product of the bandwidth and distance 10053. Sum of the bandwidth and distance 10054. Difference of the bandwidth and distance 10055. Quotient of bandwidth and distance 10056. 10057. 10058. The _____ of a detector is the fraction of incident photons that produce a photoelectron or electron-hole pair 10059. Responsitivity 10060. Photon efficiency 10061. Aperture 10062. Quantum efficiency 10063. 10064. 10065. In solid-state optical detectors, the excited charge is transported in the solid by 10066. Holes and protons 10067. Holes and electrons 10068. Anion and cation 10069. Protons and photons 10070. 10071. 10072. One of the following is not a solid-state optical detector 10073. APD 10074. PIN 10075. PMT 10076. Phototransistors 10077. 10078. 10079. Optical detectors are square-law devices because they respond to _____ rather than amplitude 10080. Intensity 10081. Light 10082. Density 10083. Photon 10084. 10085. 10086. The _____ is equal to the number of electrons emitted per second times the electron charge 10087. Intensity 10088. Optical power 10089. Photocurrent 10090. Responsitivity 10091. 10092. 10093. Which optical detector is used when high sensitivity and bandwidth are required? 10094. PMT 10095. APD 10096. PIN 10097. Phototransistor 10098. 10099. 10100. What is the average loss in fiber splice? 10101. 0.10 dB 10102. 0.15 dB 10103. 0.20 dB 10104. 0.25 dB 10105. 10106. 10107. Which of the following colors is not found in the visible light wave spectrum? 10108. Red 10109. White 10110. Orange 10111. Yellow 10112. 10113. 10114. What is the frequency limit of an optical fiber? 10115. 20 GHz 10116. 30 GHz 10117. 40 GHz 10118. 50 GHz 10119. 10120. 10121. The mechanical splice attenuation loss is _____ dB or less 10122. 0.1 10123. 0.01 10124. 0.001 10125. 1 10126. 10127. 10128. _____ is applied to protect core and cladding of the fiber 10129. Insulation 10130. Fiber insulation 10131. Silica 10132. Polymer jacket 10133. 10134. 10135. The energy of the photon is 10136. Directly proportional to its bandwidth 10137. Directly proportional to the Planck’s constant 10138. Directly proportional to Boltzmann’s constant 10139. Inversely proportional to the Planck’s constant 10140. 10141. 10142. Refractive index of glass 10143. 1.0 10144. 1.2 10145. 1.4 10146. 1.5 10147. 10148. 10149. Refractive index of diamond 10150. 1.0 10151. 1.4 10152. 1.8 10153. 2.0 10154. 10155. 10156. What is the unit of light wavelength? 10157. Micrometer 10158. Angstroms 10159. Mils 10160. Fathom 10161. 10162. 10163. How much is the power loss of the fusion splice? 10164. 0.1 dB or less 10165. 0.01 dB or less 10166. 1 dB or less 10167. 10 dB or less 10168. 10169. 10170. Used to test a fiber optics splice 10171. Spectrum analyzer 10172. Oscilloscope 10173. Optical power meter 10174. Field strength meter 10175. 10176. 10177. A coupler which consists of a series of lenses and a partly reflective surface 10178. Beam-splitting coupler 10179. Reflective star coupler 10180. Fused coupler 10181. None of these 10182. 10183. 10184. Reflections in many directions 10185. Diffuse reflection 10186. Diffraction 10187. Scattering 10188. Dispersion 10189. 10190. 10191. Commonly used electro-optic crystal for polarization modulation 10192. Lithium Niobate 10193. Tourmaline 10194. Sodium Chlorate 10195. Sphalerite 10196. 10197. 10198. Which modulation methods are the most widely used in optical systems? 10199. Phase and frequency modulations 10200. Polarization modulation and phase modulation 10201. Intensity modulation and phase modulation 10202. Intensity modulation and polarization modulation 10203. 10204. 10205. 10206. 10207. 10208. 10209. BROADCASTING 10210. 10211. 10212. Which of the following is the first component of any MATV system to receive broadcast signals? 10213. Filter 10214. LNA 10215. RF amplifier 10216. Antenna 10217. 10218. 10219. Is the most common technique where apartment house, hotels, schools, condominiums, and multi-unit buildings distribute TV and FM signals to a number of receivers, using a single head-end. 10220. CCTV 10221. CATV 10222. MATV 10223. Antenna 10224. 10225. 10226. TV channel 2, 4 and 5 belong to 10227. Low band UHF 10228. High band VHF 10229. Mid band UHF 10230. Low band VHF 10231. 10232. 10233. A mechanism or device which enables the TV camera to move in lateral and tilting motion 10234. Panning device 10235. Scanner 10236. Tilting 10237. Pan/tilt device 10238. 10239. 10240. Which of the following is a solid state imaging device? 10241. VIDICON 10242. ICONOSCOPE 10243. Charge couple device 10244. CCTV 10245. 10246. 10247. What class of TV camera lens used to cover short distances? 10248. Normal 10249. Wide angle 10250. Telephoto 10251. Zoom 10252. 10253. 10254. What class of TV camera lens used to cover long distances? 10255. Normal 10256. Wide angle 10257. Telephoto 10258. Zoom 10259. 10260. 10261. What is the local oscillator frequency in commercial AM broadcast if it is equal to 455 kHz? 10262. 0 to 1500 kHz 10263. 0 to 455 kHz 10264. 540 to 1600 kHz 10265. 955 to 2055 kHz 10266. 10267. 10268. What is the allowable deviation ratio of commercial FM broadcast? 10269. 20 10270. 75 10271. 5 10272. 25 10273. 10274. 10275. The maximum power suggested by KBP on 919-1312 AM broadcast station in Metro Manila is 10276. 5 kW 10277. 10 kW 10278. 15 kW 10279. 20 kW 10280. 10281. 10282. KBP radio code mandates that station must provide a minimum of ___ minutes 10283. 30 10284. 45 10285. 50 10286. 60 10287. 10288. 10289. What is the chroma subcarrier signal frequency for color television? 10290. 3.8 MHz 10291. 6.8 MHz 10292. 7.8 MHz 10293. 8.8 MHz 10294. 10295. 10296. What is the frequency tolerance of an FM Radio Broadcast station? 10297. ± 20000 Hz 10298. ± 20 Hz 10299. ± 200 Hz 10300. ± 2000 Hz 10301. 10302. 10303. The minimum frequency separation between frequency of AM broadcasting station 10304. 9 kHz 10305. 18 kHz 10306. 36 kHz 10307. 72 kHz 10308. 10309. 10310. 10311. 10312. The aspect ratio HDTV is 10313. 4:3 10314. 18:5 10315. 14:8 10316. 16:9 10317. 10318. 10319. A newscast is a distinct unit of a program with a minimum news content of _____ minute(s) excluding intro, extro, headline and commercial load 10320. 1 10321. 2 10322. 3 10323. 4 10324. 10325. 10326. In accordance with existing provision of law and the KBP rules and the regulations, all stations shall actively promote the growth ands the development of Filipino music by playing _____ OPM every clock hour. 10327. 1 10328. 2 10329. 3 10330. 4 10331. 10332. 10333. Commercial load for radio shall not exceed ____ minutes for a one-hour program outside Metro Manila 10334. 15 10335. 20 10336. 25 10337. 30 10338. 10339. 10340. Commercial load for radio shall not exceed _____ minutes for a one-hour program outside Metro Manila. 10341. 15 10342. 16 10343. 17 10344. 20 10345. 10346. 10347. Program interruption for airing of commercial in Metro Manila shall not exceed _____ breaks in every program hour 10348. 5 10349. 6 10350. 7 10351. 8 10352. 10353. 10354. Program interruption for the airing of commercial outside Metro Manila shall not exceed _____ breaks in every program hour 10355. 5 10356. 6 10357. 7 10358. 8 10359. 10360. 10361. For Metro manila, the classification of prime time blocks for FM shall be 10362. 6:00 AM to 8:00 PM 10363. 6:00 AM to 12:00 NN 10364. 6:00 AM to 6:00 PM 10365. 12:00 NN to 12:00 MN 10366. 10367. 10368. For provincial station, the classification of prime time blocks for FM radio shall be 10369. 6:00 AM to 8:00 PM 10370. 6:00 AM to 12:00 NN 10371. 6:00 AM to 6:00 PM 10372. 12:00 NN to 12:00 MN 10373. 10374. 10375. All airtime classifications shall be submitted to and subject for approval by the 10376. NTC 10377. KBP-SA 10378. DOTC 10379. CCITT 10380. _____ is the time circulation for one horizontal trace 10381. 52 us 10382. 62 us 10383. 48 us 10384. 50 us 10385. 10386. 10387. Listing of the date and time of events, programs, equipment, tests, malfunctions and corrections in communications system. 10388. Reporting 10389. Documentation 10390. Log 10391. File 10392. 10393. 10394. Which of the following is not a low impedance microphone? 10395. Dynamic 10396. Velocity 10397. Condenser 10398. Crystal 10399. 10400. 10401. Facsimile permits remote duplications of which of the following items? 10402. Map 10403. Pictures 10404. Printed page 10405. All of these 10406. 10407. 10408. Television has a lot of features in common with 10409. FM stereo 10410. Telephone service 10411. Motion picture 10412. Magazine 10413. 10414. 10415. The major component of the TV signal waveform is the 10416. Video 10417. Radar 10418. Stereo 10419. Antenna 10420. 10421. 10422. For NTSC TV system, the image is scanned from 10423. Top to bottom 10424. Left to right 10425. Right to left 10426. Choices A and B above 10427. 10428. 10429. One completes NTSC scanning cycle called field consists of how many lines 10430. 500 10431. 525 10432. 625 10433. 60 10434. 10435. 10436. The field rate in the NTSC television system 10437. 30 Hz 10438. 120 Hz 10439. 60 Hz 10440. 15.75 Hz 10441. 10442. 10443. What is the horizontal synchronous blanking pulse rate? 10444. 30 Hz 10445. 60 Hz 10446. 15.75Hz 10447. 120 Hz 10448. 10449. 10450. What is the vertical blanking pulse rate? 10451. 30 Hz 10452. 60 Hz 10453. 15.75 Hz 10454. 120 Hz 10455. 10456. 10457. The pulses riding on the vertical blanking pulse 10458. Equalizing (sync) pulses 10459. Serrated vertical sync pulses 10460. Black level pulses 10461. Choices A and B above 10462. 10463. 10464. Television camera pickup tube is called 10465. Vidicon 10466. Image orthicon 10467. Plumbicon 10468. All of the above 10469. 10470. 10471. The television picture tube magnetic fields can be used for 10472. Beam focusing 10473. Beam deflection 10474. Beam production 10475. Beam modulation 10476. 10477. 10478. What is the purpose of an indirectly-heated cathode in a cathode ray tube? 10479. Beam focusing 10480. Beam deflection 10481. Beam production 10482. Beam modulation 10483. 10484. 10485. Video modulation for television is 10486. Amplitude modulation 10487. Frequency modulation 10488. Vestigial sideband 10489. Both amplitude modulation and vestigial sideband 10490. 10491. 10492. Audio modulation for television is 10493. Amplitude modulation 10494. Frequency modulation 10495. Vestigial sideband 10496. Both amplitude modulation and vestigial sideband 10497. 10498. 10499. What is the maximum frequency deviation for audio modulation in TV transmission? 10500. 25 kHz 10501. 30 kHz 10502. 50 kHz 10503. 75 kHz 10504. 10505. 10506. The video carrier and the audio carrier are separated by ____ MHz. 10507. 4.5 10508. 5.5 10509. 6.5 10510. 7.5 10511. 10512. 10513. In a practical image scanned at the NTSC rate, the spectrum will include components clustered at the fundamentals and harmonics of _____ kHz 10514. 15.75 10515. 30 10516. 12.25 10517. 45.5 10518. 10519. 10520. Brightness of an image is known as 10521. Radiance 10522. Chrominance 10523. Reflectance 10524. Luminance 10525. 10526. 10527. The colors at the vertices of the color triangle are referred to as 10528. Primary 10529. White 10530. Desaturated 10531. All of the above 10532. 10533. 10534. A color signal which originate in the camera itself with color television pickup? 10535. Red 10536. Green 10537. Blue 10538. All of these 10539. 10540. 10541. What are the three separate signals derived from a matrix in a color TV transmitter? 10542. Y, I and Q 10543. P, D and Q 10544. M, N and O 10545. R, S and T 10546. 10547. 10548. Range of a VHF television transmitter 10549. 54 – 98 MHz 10550. 54 – 216 MHz 10551. 54 – 128 MHz 10552. 54 – 166 MHz 10553. 10554. 10555. Range of a UHF television transmitter 10556. 470 – 670 MHz 10557. 470 – 770 MHz 10558. 470 – 890 MHz 10559. 470 - 980 MHz 10560. 10561. 10562. What is the approximate bandwidth occupied by the chrominance video signal for color TV? 10563. 0.8 MHz 10564. 1.8 MHz 10565. 8.1 MHz 10566. 1.6 MHz 10567. 10568. 10569. The colors found around the perimeter of the color triangle are said to be 10570. Saturated 10571. Dark 10572. Light 10573. Monochrome 10574. 10575. 10576. At what position on the color triangle will saturated yellow be located? 10577. Between red and blue 10578. Between red and green 10579. Between blue and green 10580. At the center 10581. 10582. 10583. What is the phase difference between the I and Q color signal carriers? 10584. 0° 10585. 45° 10586. 60° 10587. 90° 10588. 10589. 10590. _____ is the most effective filter for separating luminance and chrominance frequency components. 10591. Low pass 10592. Band pass 10593. Notch 10594. Comb 10595. 10596. 10597. The chrominance processing circuits can be deactivated when monochrome broadcasts are received by the 10598. Color killer 10599. SAW filter 10600. NOT gate 10601. All of the above 10602. 10603. 10604. What is the standard video level, in percent PEV, for blanking? 10605. 25 % 10606. 0 % 10607. 12.5 % 10608. 75 % 10609. 10610. 10611. What is the percent video level, in percent PEV, for black? 10612. 0 % 10613. 25 % 10614. 12.5 % 10615. 70 % 10616. 10617. 10618. What is the standard video level, in percent PEV, for white? 10619. 0 % 10620. 12.5 % 10621. 25 % 10622. 70 % 10623. 10624. 10625. One should first perform _____ before a convergence setup is performed. 10626. Gray tracking 10627. Screen setting 10628. Alignment 10629. Degaussing 10630. 10631. 10632. If there are too many harmonics, one should check the 10633. Coupling 10634. Tuning of circuits 10635. Shielding 10636. Any of these 10637. 10638. 10639. In transmitter amplifier design, an even-order harmonics can be prevented or reduced by 10640. Using a push-pull amplifier 10641. Operating class C 10642. Operating class AB 10643. All of these 10644. 10645. 10646. The vertical and horizontal pulses are separated at the 10647. Sync separator 10648. AFC 10649. High voltage 10650. AGC 10651. 10652. 10653. The reason why buffer stage is included in a transmitter is to 10654. Present a constant load to the oscillator stage 10655. Present a low impedance to the oscillator stage 10656. Stop the oscillator from generating parasitic oscillations 10657. All of these 10658. 10659. 10660. Where is the operating position of a radio station? 10661. On the bridge 10662. At the control point 10663. At the location of the receiver 10664. At the location of the transmitter 10665. 10666. 10667. The alignment of the three color guns to a common point is known as 10668. Blooming 10669. Confetti 10670. Demodulation 10671. Convergence 10672. 10673. 10674. A _____ is equivalent to 525 scanning lines 10675. Field 10676. Frame 10677. Cycle 10678. Interface set 10679. 10680. 10681. A _____ represents one set of 262 ½ scanning lines 10682. Field 10683. Frame 10684. Cycle 10685. Interface set 10686. 10687. 10688. The number of scanning lines is _____ per second 10689. 14750 10690. 15570 10691. 15750 10692. 16550 10693. 10694. 10695. Picture frames are repeated at the rate of _____ per second 10696. 25 10697. 30 10698. 40 10699. 50 10700. 10701. 10702. Lack of raster is an indication of no 10703. AGC 10704. High voltage 10705. Video signal 10706. Television signal 10707. 10708. 10709. The sound and video signals are separated at the _____ of the TV receiver 10710. IF stage 10711. Video amplifier 10712. Video detector 10713. Burst separator 10714. 10715. 10716. The presence of color bars is an indication that there is a problem in the _____ circuit 10717. Horizontal 10718. Reactor 10719. Burst separator 10720. Chroma amplifier 10721. 10722. 10723. Type of emission produced when a frequency modulated transmitter is modulated by a TV signal 10724. A3F 10725. F3F 10726. A3C 10727. F3C 10728. 10729. 10730. What is emission A3F? 10731. RTTY 10732. SSB 10733. TV 10734. Modulated CW 10735. 10736. 10737. What is emission F3F? 10738. Facsimile 10739. Modulated CW 10740. Television 10741. RTTY 10742. 10743. 10744. Cause of slow rising white “hum bars” is the television 10745. Pad filter 10746. Bad rectifier 10747. Bad picture tube 10748. High voltage transformer 10749. 10750. 10751. Adjusting the _____ may eliminate color confetti 10752. Color chroma amplifier 10753. Color killer 10754. Color detector 10755. Color oscillator 10756. 10757. 10758. Video signal amplitude determine the picture quality called 10759. Chrominance 10760. Brightness 10761. Contrast 10762. Luminance 10763. 10764. 10765. Part of broadcast day from midnight to local sunrise 10766. Daytime 10767. Experimental 10768. Nighttime 10769. Dawntime 10770. 10771. 10772. Part of broadcast day from local sunset to local sunrise 10773. Dawntime 10774. Nighttime 10775. Daytime 10776. Experimental 10777. 10778. 10779. What causes snow in television? 10780. High Q in the tuned circuit 10781. Excessive gain 10782. Random noise in the signal 10783. Insufficient wave traps 10784. 10785. 10786. Vestigial sideband is known as _____ type of emission 10787. CF3 10788. C3F 10789. B8E 10790. A3E 10791. 10792. 10793. Vestigial sideband modulation is commonly used in 10794. TV broadcasting 10795. Monaural broadcasting 10796. Stereo broadcasting 10797. HF point-to-point communications 10798. 10799. 10800. Which of the following filters block FM radio band for TV channels (2 to 13)? 10801. High-pass filter 10802. Low-pass filter 10803. Band pass filter 10804. Band-reject filter 10805. 10806. 10807. The FM broadcast band is from 10808. 535 to 1600 kHz 10809. 30 to 300 kHz 10810. 88 to 108 MHz 10811. 300 to 2000 MHz 10812. 10813. 10814. The type of emission used by standard AM radio broadcast 10815. A5C 10816. A0 10817. A3 10818. F3 10819. 10820. 10821. The standard AM radio broadcast belongs to which frequency band? 10822. MF 10823. HF 10824. VHF 10825. LF 10826. 10827. 10828. When were UHF channels (14 – 83) of television added? 10829. 1902 10830. 1945 10831. 1947 10832. 1952 10833. When was colored TV standards established in the United States? 10834. 1904 10835. 1945 10836. 1953 10837. 1960 10838. 10839. 10840. What synchronizes the horizontal line of the TV picture tube? 10841. HFC 10842. HSC 10843. HAFC 10844. All of these 10845. 10846. 10847. A measure of how well the receiver can respond to every weak signals/ 10848. Selectivity 10849. Sensitivity 10850. Fidelity 10851. Quality factor 10852. 10853. 10854. What is the allowable frequency deviation of a commercial FM broadcast band? 10855. 15 kHz 10856. 75 kHz 10857. 5 kHz 10858. 100 kHz 10859. 10860. 10861. The final amplifier of either FM or AM transmitter is operated as 10862. Class A 10863. Class B 10864. Class C 10865. Class D 10866. 10867. 10868. Standard AM broadcasting use _____ for greater and efficient coverage 10869. Circular polarized wave antenna 10870. Horizontal polarized wave antenna 10871. Both vertical and horizontal polarized wave antenna 10872. Vertical polarized wave antenna 10873. 10874. 10875. Receiver sensitivity means 10876. The frequency allocation of the system 10877. Input impedance of the receiver 10878. The ability of picking up weak signal 10879. The power to deliver the information 10880. 10881. 10882. The main functions of the RF amplifier in a superheterodyne receiver is to 10883. Provide improved tracking 10884. Permit better adjacent-channel rejection 10885. Improve the rejection of the image frequency 10886. All of these 10887. 10888. 10889. Local oscillator of a broadcast receiver always tunes to a frequency higher than the incoming frequency in order 10890. To help the image frequency rejection 10891. To allow easy tracking 10892. To allow adequate frequency coverage without switching 10893. All of these 10894. 10895. 10896. Type of filter used in TV receivers that separates the chroma signal from the colorplexed video signal but leaves intact the Y-component 10897. Comb filter 10898. Bandpass filter 10899. Color filter 10900. Low pass filter 10901. 10902. 10903. What is the first letter-symbol for emission of unmodulated carrier? 10904. A 10905. N 10906. H 10907. F 10908. 10909. 10910. The channel for cable TV frequency range of 5.75 to 11.75 MHz 10911. T-1 10912. T-8 10913. 2 10914. 3 10915. 10916. 10917. The frequency range for cable TV channel T-13 10918. 23.75 – 29.75 MHz 10919. 60 – 66 MHz 10920. 41.75 – 47.55 MHz 10921. 5.75 – 11.75 MHz 10922. 10923. Channel 8 frequency range allocation in cable TV 10924. 54 – 60 MHz 10925. 66 – 72 MHz 10926. 180 – 186 MHz 10927. 204 – 210 MHz 10928. 10929. 10930. The _____ of a television system is a measure of its ability to delineate picture detail 10931. Contrast 10932. Resolution 10933. Hue 10934. Pixels 10935. 10936. 10937. CCIR standards for the internal exchange of programmes on film for television used 10938. Rec 265-6 10939. Rec 407-4 10940. Rec 408-5 10941. Rec 450-1 10942. 10943. 10944. CCIR transmission standards for FM sound broadcasting at VHF 10945. Rec 601.2 10946. Rec 501.2 10947. Rec 500.4 10948. Rec 450.1 10949. 10950. 10951. ISO Rec 23 in 1976 is the standard for 10952. Recorded characteristics for magnetic sound records on full cost 16 mm motion picture film 10953. Projector usage of 16 mm motion picture films for direct front projector 10954. Camera usage of 35 mm motion picture film 10955. Camera usage of 16 mm motion picture film 10956. 10957. 10958. International broadcasting (short wave) uses frequency between _____ accordance with international agreements 10959. 7012 and 26100 kHz 10960. 6409 and 26100 kHz 10961. 5950 and 26100 kHz 10962. 10950 and 26100 kHz 10963. 10964. 10965. Which of the following station below is a regional channel? 10966. Class I-A 10967. Class II-D 10968. Class III-B 10969. Class IV 10970. 10971. 10972. The permissible power in kW of station II-A during nighttime is 10973. 0.25 – 50 10974. 10 – 50 10975. 1 – 5 10976. None of these 10977. 10978. 10979. The television frequency which are now allocated to the land mobile services 10980. 806 and 192 MHz 10981. 800 and 806 MHz 10982. 668 and 674 MHz 10983. 776 and 782 MHz 10984. 10985. 10986. Numerical frequency band designation of channel 9 10987. 488 – 494 MHz 10988. 530 – 536 MHz 10989. 632 – 638 MHz 10990. 186 – 192 MHz 10991. 10992. 10993. Cable TV systems originate from 10994. Germany 10995. Dallas, Texas 10996. Pennsylvania 10997. Japan 10998. 10999. 11000. A term applied to third and higher order products, which can greatly degrade the performance of a system 11001. Composite triple beat 11002. Single dual mode 11003. Field strength 11004. Noise 11005. 11006. 11007. A station similar to a translator station in terms of equipment and service area but is permitted to originate originate programming from virtually any source 11008. DME 11009. LPTV 11010. HDTV 11011. ITFS 11012. 11013. 11014. Three stations are licensed to eligible educational entities for the distribution of program material to students enrolled in instructional curricula 11015. Translator 11016. LPTV 11017. HDTV 11018. ITFS 11019. 11020. 11021. ITFS means 11022. International Television Frequency Standard 11023. Instructional Telephone Frequency Service 11024. Instructional Television Fixed Service 11025. International telecommunications Frequency Standard 11026. 11027. 11028. MDS means 11029. Multipoint Distribution Service 11030. Multipoint Digital Service 11031. Maritime Data Standards 11032. Multipoint Drop Standards 11033. 11034. 11035. Direct broadcast satellite based allocation 11036. 12.2 – 12.7 GHz downlink 11037. 17.3 – 17.8 GHz for uplink 11038. 3.7 – 4.2 GHz for downlink 11039. 12.2 – 12.7 GHz for downlink and 17.3 – 17.8 GHz for uplink 11040. 11041. 11042. What is the channel number of an FM station with 88.1 MHz carrier? 11043. 201 11044. 202 11045. 203 11046. 204 11047. 11048. 11049. What is the carrier frequency of an FM station with channel number of 300? 11050. 107.5 MHz 11051. 101.1 MHz 11052. 107.9 MHz 11053. 99.5 MHz 11054. If an FM station has an effective radiated power of 100 kW then it is under what class? 11055. Class A 11056. Class B 11057. Class C 11058. Class D 11059. 11060. 11061. The video signal amplitude determines the quality of the picture otherwise known as 11062. Hue 11063. Luminance 11064. Chrominance 11065. Contrast 11066. 11067. 11068. _____ is defined as to “send out in all direction” 11069. Broadcast 11070. Announce 11071. Media 11072. All of these 11073. 11074. 11075. The ultimate Dolby surround system is the 11076. Dolby NR 11077. Dolby Prologic 11078. dBx 11079. hall matrix 11080. Microwave Communications 11081. 11082. ______is the progressive decrease of signal strength with increasing distance. 11083. Radiation Attenuation Modulation Propagation 11084. 11085. Calculate the effective earth’s radius if the surface refractivity is 301. 11086. 8493 km 8493 mmi 6370 km 6370 mi 11087. 11088. If k-factor is greater than 1, the array beam is bent 11089. Away from the earth towards the ionosphere, towards the earth towards the outer space 11090. 11091. the antenna separations (in meters) required for optimum operation of a space diversity system can be calculated from: 11092. S = 2λR/L S = 3λR/L S = λR/RL S = λR/L 11093. 11094. where R = effective earth radius (m) and L = path length (m) 11095. 11096. Rainfall is an important factor for fading of radio waves at frequencies above 11097. 10 GHz 100 GHz 1 GHz 100 MHz 11098. 11099. Theoretically electromagnetic radiation field strength varies in inverse proportion to the square of the distance, but when atmospheric attenuation effects and the absorption of the terrain are taken into account the attenuation can be as high as the inverse ______power of the distance. 11100. Third Fourth Fifth Sixth 11101. 11102. 11103. What do you call an attenuation that occurs over many different wavelengths of the carrier? 11104. Rayleigh fading Rician fading Wavelength fading Slow fading 11105. 11106. Which of the reception problems below that is not due to multipath? 11107. Delayed spreading Rayleigh fading Random Doppler shift Slow fading 11108. 11109. Which causes multipath or frequency-selective fading? 11110. Small reflector Nearer reflector Further reflector Large reflector 11111. 11112. In microwave transmission using digital radio, what causes most intersymbol interference? 11113. Delayed spreading Rayleigh fading Random Doppler shift Slow fading 11114. 11115. A shipboard equipment which measures the distance between the ship’s bottom and the ocean floor. 11116. Fathometer Echosounder LORAN SONAR 11117. 11118. The cavity resonator 11119. Is equivalent to an LC resonant circuit In a reflect klystron has its output taken from the reflector plate Produces a frequency which is independent of the cavity size. Has a low Q factor for narrow operation. 11120. 11121. At what position is the input signal inserted into a traveling-wave tube? 11122. At the cathode end of the helix At the collector At the collector end of the helix At the control grid of the electron gun 11123. 11124. Coupling into and out of a traveling-wave tube can be accompanied by a 11125. Waveguide match Cavity match Direct coax-helix match All of the above 11126. 11127. a high-power microwave pulse of the order of megawatts can be generated by a 11128. traveling-wave tube magnetron reflex klystron Gunn diode 11129. 11130. A traveling-wave tube (TWT) amplifies by virtue of 11131. The absorption of energy by the signal from an electron stream The effect of an external magnetic field The energy contained the cavity resonators The energy liberated form the collector 11132. 11133. What is the purpose of the electromagnetic field which surrounds a traveling- wave tube? 11134. To accelerate the electron To velocity modulate the electron beam To keep the electrons from spreading out To slow down the signal on the helix 11135. 11136. Which of the following is used as an oscillator device in the SHF band? 11137. Thyratron tube Tunnel diode Klystron tube Both B and C 11138. 11139. Microwave frequencies are normally regarded as those in the range of 11140. 1 to 500 MHz 1000 to 10,000 GHz 1 to 100 GHz 10 to 1000 GHz 11141. 11142. The highest frequency which a conventional vacuum-tube oscillator can generate is not limited by the 11143. Electron transit time Distributed lead inductance Inter-electrode capacitance Degree of emission from the cathode 11144. 11145. As the electron beam moves through a klystron’s intercavity drift space 11146. Frequency modulation at the input cavity creates velocity modulation at the output cavity Velocity modulation at the input cavity creates density modulation at the output cavity Density modulation at the input cavity creates velocity modulation at the output cavity Phase modulation at the input cavity creates velocity modulation at the output cavity. 11147. 11148. The frequency of the oscillation generated by a magnetron, is mainly determined by 11149. The flux density of the external magnet The ratio of the dc cathode voltage to the magnetic flux density The number of the cavity resonators The dimension of each cavity resonator 11150. 11151. If the instantaneous RF potentials on the two sides of a magnetron cavity are of opposite polarity, the operation is in the 11152. π mode π/2 mode 2π mode π/4 mode 11153. 11154. The Gunn diode oscillator 11155. Is capable of generating continuous microwave power of the order of kilowatt Generates frequencies which are below 100 MHz Operates over a positive resistance characteristic Depends on the formation of charge domain 11156. 11157. What ferrite device can be used instead of duplexer of isolate microwave transmitter and receiver when both are connected to the same antenna? 11158. Isolator Magnetron Simplex Circulator 11159. 11160. To achieve good bearing resolution when using a pulsed-radar set, an important requirement is 11161. A narrow, antenna-beam width in the vertical plane A narrow, antenna-beam width in the horizontal plane A low repetition rate A high duty cycle 11162. 11163. When used in conjunction with a radar set, the purpose of an echo box is to provide an artificial target. 11164. Which may be used to tune the radar synchronizer Which may be used to tune the radar receiver To the tone of the pulse repetition Tune the magnetron to the correct frequency 11165. 11166. In a radar-set receiver, the usual mixer stage is 11167. And FET A tunnel diode A silicon crystal A Rochelle salts crystal 11168. 11169. Klystron oscillators are most often used in the frequency range of 11170. 300 to 3000 MHz 3000 to 30000 MHz 30 to 30000 MHz 10 to 10000 MHz 11171. 11172. Oscillators of a klystron tube are maintained 11173. By bunches of electrons passing the cavity grids By plate-to-cathode feedback By feedback between the accelerating grid and the repeller By circulating bunches of electrons within the cavities. 11174. 11175. What allow microwave to pass in only one direction? 11176. RF emitter Capacitor Varactor-triac Ferrite emitter 11177. 11178. In an SHF pulsed radar set, a reflex klystron can be used as a 11179. Single mixer stage Local oscillator Transmitter oscillator Duplexer stage 11180. 11181. A Class-S Emergency Position-Indicating Radio Beacon (E.P.I.R.B) 11182. Must be capable of floating or being secured to a survival Must have its battery replaced after emergency use May be tested during the first five minutes of any hour All of these 11183. 11184. A PPI cathode-ray tube as used on a radar set 11185. Is used to check the percentage of modulation Indicates both the range and azimuth of a target Indicates only the range of a target Is used for receiver alignment 11186. 11187. The resonant frequency of a cavity resonator depends upon 11188. The mode of operation Its electrical dimensions Its physical dimensions The capacitor which tunes it 11189. 11190. The maximum usable range of the usual radar set (on any particular range setting) is determined by 11191. The width of the transmitted pulses The interval between transmitted pulses The bandwidth of the receiver IF stages The duty cycle 11192. 11193. A reflex klystron is oscillating at the frequency of its resonant cavity. If the reflector voltage is made slightly less negative, the 11194. Oscillation will cease Output power would increase The frequency will decrease Bunching would occur earlier in time 11195. 11196. The coarse frequency adjustment of a reflex klystron is accomplished by 11197. The AFC system Adjusting the flexible wall of the resonant cavity An adjustment in the synchronizer Varying the repeller voltage 11198. 11199. In a pulsed radar set, the STC circuit is used to 11200. Improve the target bearing resolution Increases receiver sensitivity for echoes from targets Vary the pulse frequency in order to control the maximum target Reduce interference from the effects of sea return 11201. 11202. In a pulsed radar set, the function of the duplexer is to 11203. Aid in calibrating the display unit Prevent frequency drift in the klystron Allow the transmitter and the receiver to operate from a common antenna All of these 11204. 11205. A magnetron is operated at a duty cycle of 0.001. It has a peak power output of 100 kilowatts. Its average power is 11206. 10,000 watts 100 watts 1,000 watts 1,000,000 watts 11207. 11208. The aquadag coating on the inside of PPI tube is used 11209. To focus the beam of primary electrons To shield the electron beam from unidirectional magnetic As a second anode and to prevent the build-up of secondary field All of these 11210. 11211. If the duration of the radar transmitted pulse, on a particular range of operation, is increased, the required bandwidth of the receiver’s IF amplifiers 11212. Must remain as before Must be increased May be decreased Must be doubled 11213. 11214. The main frequency determining element of a klystron is 11215. The repeller voltage The accelerating voltage Its resonant cavity Its mode of operation 11216. 11217. A thin layer of dirt and grime coverts the reflecting surface of the parabolic dish of a radar set. The particular effect on the performance of the radar will be 11218. A decrease in range A reduction in horizontal resolution No noticeable effect A decrease in gain 11219. 11220. Which of the following permits a microwave signal to travel in one direction with virtually no loss, but severely attenuates any signal attempting to travel in the reverse direction? 11221. Isolator Wave trap Tunnel diode Circulator 11222. 11223. It is possible to increase the maximum range of a radar equipment by 11224. Lowering the pulse frequency Raising the peak power of the transmitter Narrowing the beam width and increasing the pulse duration All of these 11225. 11226. When it is desired that short-range targets be clearly seen on a pulsed-radar set, it is important that the receiver and display system have 11227. A long time constant Low-pass filters The shortest possible time The restricted high-frequency response 11228. 11229. Which of the following is used as a high power microwave oscillator? 11230. Thyratron Magnetron Klystron Reflex-klystron 11231. 11232. Which of the following operating frequencies is used for the modern loran navigational system? 11233. Loran C: 100 kHz Loran D: 10.2 kHz Loran A: 1950 kHz Loran B: 900 kHz 11234. 11235. Which ferrite device can be used instead of a duplexer to isolate a microwave transmitter and receiver when both are connected to the same antenna? 11236. Isolator Magnetron Simplex Circulator 11237. 11238. The pulse frequency is equal to 11239. Duty cycle/pulse width The reciprocal of the pulse repetition rate Pulse width x peak power/average power All of these 11240. 11241. In a radar set, a blocking oscillator can be used to 11242. Act as the local oscillator converter stage Provide the sweep voltage for the PPI tube Produce a trigger pulse for the transmitter As a single local oscillator converter stage 11243. 11244. The intensity of the echoes (target definition) on a PPI display is determined by the 11245. Radio frequency Pulse frequency and antenna rotation rate Duty cycle Average power 11246. 11247. A duplexer circuit allows a transmitter and a receiver to operate from the same antenna with virtually no interaction. This circuit may be replaced by a (an) 11248. loss waveguide circulator isolator gyrator 11249. 11250. Which of the following frequencies are used by a class-C Emergency Position- Indicating Radio Beacon (E.P.I.R.B)? 11251. 156.65 MHz 121.5 MHz 156.76 MHz and 156.8 MHz All of these 11252. 11253. The repetition rate of a pulsed radar system indicates the 11254. Frequency of the range-marker oscillator Reciprocal of the duty cycle Number of target echoes received on one second Frequencies of the duty cycle 11255. 11256. The radar set, sensitivity-time control circuit 11257. Controls the width of the magnetron pulse Is used to increase sea return Can reduce sea-return response Discriminates between targets that are very close together. 11258. 11259. Which of the following is the ferrite device that buffers a microwave source from the effects of a varying load, and thereby prevents the formation of standing waves? 11260. Circulator Duplexer Isolator Diplexer 11261. 11262. Pulsed radar sets are primarily used to find the 11263. Target’s range and bearing Size and speed of a target Speed and course of a target Target’s range of speed 11264. 11265. Which of the following factors is mainly concerned in the design of an antenna system for pulsed radar set? 11266. Duty cycle Radio frequency Pulse frequency Pulse length 11267. 11268. In a radar set receivers, an ac AFC system may be used to 11269. Automatically maintain the correct magnetron frequency Keep the IF stages on frequency Maintain the desired klystron frequency Provide automatic control of receiver gain 11270. 11271. The input signal is introduced into the traveling-wave tube at the 11272. Cathode Anode Cathode end of the helix Collector end of the helix 11273. 11274. The display on the PPI scope of a radar set will have greater intensity under the following conditions 11275. Higher antenna rotation speeds Lower pulse repetition rate Lower antenna rotation speeds Both lower antenna rotation speeds and higher pulse repetition 11276. 11277. The operating frequency of loran C lies within the 11278. LF band VLF band MF band HF band 11279. 11280. The PPI tubes have an aquadag coating on the inside of the tube. The purpose of this coating is 11281. To act as the second anode To shield the tube magnetically To decelerate the electron beam To deflect the electron beam 11282. 11283. A traveling-wave tube Is used at frequencies in the order of 11284. 30 MHz 300 MHz 8000 MHz 100 MHz 11285. 11286. The main benefit of using microwaves is 11287. Lower-cost equipment Simpler equipment Greater transmission distances More spectrum space for signals 11288. 11289. Radio communication are regulated in the Philippines by the 11290. DOTC KBP NTC Department of Defense 11291. 11292. Which of the following is not a disadvantage of microwaves? 11293. Higher-cost equipment Line-of-sight transmission Conventional components are not usable Circuits are more difficult to analyze 11294. 11295. Which of the following is a microwave frequency? 11296. 1.7 MHz 750 MHz 0.98 GHz 22 GHz 11297. 11298. Which of the following is not a common microwave application? 11299. Radar Mobile radio Telephone Satellite communications 11300. 11301. Coaxial cable is not widely used for long microwave transmission lines because of its 11302. High loss High cost Large size Excessive radiation 11303. 11304. Stripline and microstrip transmission lines are usually made with 11305. Coax Parallel wires Twisted pair PCBs 11306. 11307. The most common cross section of a waveguide is a 11308. Square Circle Triangle Rectangle 11309. 11310. A rectangular waveguide has a width of 1 inch and a height of 0.6 in. Its cutoff frequency is 11311. 2.54 GHz 3.0 GHz 5.9 GHz 11.8 GHz 11312. 11313. A waveguide has a cutoff frequency of 17 GHz. Which of the following signals will not be passed by the waveguide? 11314. 15 GHz 18 GHz 22 GHz 255 GHz 11315. Signal propagation in a waveguide is by 11316. Electrons Holes Electric and magnetic fields Air pressure 11317. 11318. When the electric field in a waveguide is perpendicular to the direction of wave propagation, the mode is said to be 11319. Vertical polarization Horizontal polarization Transverse electric Transverse magnetic 11320. 11321. The dominant mode in most rectangular waveguide is 11322. TE 1.0 TE 1.2 TM 0.1 TM 1.1 11323. 11324. A magnetic field is introduced into waveguide by a 11325. Probe Dipole Stripline Capacitor 11326. 11327. A half-wavelength, close section of a waveguide that acts as a parallel resonant circuit is known as a(n) 11328. Half-wave section Cavity resonator LCR circuit Directional coupler 11329. 11330. Decreasing the volume of a cavity causes its resonant frequency to 11331. Increase Decrease Remain the same Drop to zero 11332. 11333. ______is a popular microwave mixer diode. 11334. Gunn Varactor Hot carrier IMPATT 11335. 11336. Varactor and step-recovery diodes are widely used in what type of circuit? 11337. Amplifier Oscillator Frequency multiplier Mixer 11338. 11339. Which diode is a popular microwave oscillator? 11340. IMPATT Gunn Varactor Schottky 11341. 11342. Which type of diodes does not ordinarily operate with reverse bias? 11343. Varactor IMPATT Snap-off Tunnel 11344. 11345. Low-power Gunn diodes are replacing 11346. Reflex klystrons TWTs Magnetrons Varactor diodes 11347. 11348. Which of the following is not a microwave tube? 11349. Traveling-wave tube Cathode-ray tube Klystron Magnetron 11350. 11351. In a klystron amplifier, velocity modulation of the electron beam is produced by the 11352. Collector Catcher cavity Cathode Buncher cavity 11353. 11354. A reflex klystron is used as a(n) 11355. Amplifier Oscillator Mixer Frequency multiplier 11356. 11357. For proper operation, a magnetron must be accompanied by a 11358. Cavity resonator Strong electric field Permanent magnet High dc voltage 11359. 11360. The operating frequency of klystrons and magnetrons is set by the 11361. Cavity resonators DC supply voltage Input signal frequency Number of cavities 11362. 11363. A magnetron is used only as a/an 11364. Amplifier Oscillator Mixer Frequency multiplier 11365. 11366. A common application for magnetron is in 11367. Radar Satellites Two-way radio TV sets 11368. 11369. In a TWT, the electron beam is density-modulated by a 11370. Permanent magnet Modulation transformer Helix Cavity resonator 11371. 11372. The main advantage of a TWT over a klystron for microwave amplification is 11373. Lower cost Smaller size Higher power Wider bandwidth 11374. 11375. High-power TWTs are replacing what in microwave amplifiers? 11376. MESFETs Magnetrons Klystrons IMPATT diodes 11377. 11378. The most widely used microwave antenna 11379. Half-wave dipole Parabolic Hyperbolic Horn 11380. 11381. ______is a measure of reliability expressed as the average number of hours between successive failures. 11382. MTBF MTTR Downtime Outage time 11383. 11384. The free space attenuation between two microwave antennas 40 km apart operating at 8 GHz is 11385. 146.7 dB 142.55 dB 82.5 dB 86.7 dB 11386. 11387. An active microwave radio repeater that can provide drops and inserts. 11388. Broadband repeater Baseband repeater IF repeater RF repeater 11389. 11390. If the correction factor k equals 4/3 of the earth’s curvature, the microwave beam would have a curvature that is ______than that of the earth. 11391. More Less Equal Not related 11392. 11393. The optimum clearance from an obstacle in an microwave system is accepted as ______of the first fresnel zone radius. 11394. 0.6 0.5 0.9 1.5 11395. 11396. The microwave beam curves the same than that of the earth when the value of the correction factor k equals 11397. 0 4/3 2/3 Infinity 11398. 11399. The time from the transmission of a radar pulse to its reception is 0.12 ms. The distance to the target is how many nautical miles? 11400. 4.85 nmi 9.7 nmi 11.2 nmi 18.4 nmi 11401. 11402. The ability of a radar to determine the bearing to a target depends upon the 11403. Antenna directivity Speed of light Speed of the target Frequency of the signal 11404. 11405. The pulse duration of a radar signal is 699ns. The PRF is 185 pulses per second. The duty cycle is 11406. 0.216 % 0.130 % 0.013 % 0.407 % 11407. 11408. The Doppler effect allows which characteristics of a target to be measured? 11409. Distance Azimuth Altitude Speed 11410. 11411. The Doppler effect is a change in what signal characteristics produced by relative motion between the radar set and a target? 11412. Amplitude Phase Frequency Duty cycle 11413. 11414. The most widely used radar transmitter component is a 11415. Klystron Magnetron TWT Power transistor 11416. 11417. Low-power radar transmitters and receivers use which component? 11418. GaAs FET Magnetron Gunn diode Klystron 11419. 11420. What component in a duplexer protects the receiver from the higher transmitter output? 11421. Waveguide Bandpass filter Notch filter Spark gap 11422. 11423. Most radar antennas use a 11424. Dipole Broadside array Horn and parabolic reflector Collinear array 11425. 11426. The most common radar display is the 11427. A scan Color CRT LCD PPI 11428. 11429. A radar antenna using multiple diploes or slot antennas in a matrix with variable phase shifters is called a/an 11430. A scan Phased array Broadside Circulator polarized array 11431. 11432. Which of the following is a typical radar operating frequency? 11433. 60 MHz 450 MHz 900 MHz 10 GHz 11434. 11435. A microwave system requires the use of repeaters when 11436. The intervening terrain is favorable The distances involve are grater The required reliability is meet The radio fading is unacceptable 11437. 11438. Are transmission lines which convey electromagnetic waves in highest frequencies 11439. Twister pair of telephone wires Waveguides Power lines Coaxial cables 11440. 11441. A microwave band of 10.9 to 36. GHz is considered as 11442. C-band X-band Q-band K-band 11443. 11444. A microwave communications system space loss calculation formula. 11445. 94.2 + 20 log f + 20 log d 92.4 + 20 log f + 20 log d 94.2 + 10 log f + 20 log d 92.3 + 10 log f + 20 log d 11446. 11447. A waveguide is also a 11448. Low pass filter High pass filter Band pass filter Band stop filter 11449. 11450. A method of diversity reception where the signal is transmitted on two difference frequencies over the same path 11451. Space diversity Frequency diversity Polarization diversity Wavelength diversity 11452. 11453. A wire used to reduce the skin effect 11454. AWG # 14 AWG # 15 Copper wire Litz wire 11455. 11456. Space diversity transmission means transmitting and receiving on two or more. 11457. Different frequencies Antennas operating on two different frequencies Antennas operating on the same frequencies Identical frequencies 11458. 11459. The best system configuration to overcome multipath fading of microwave system over the water 11460. Space diversity Frequency diversity Polarization diversity Wavelength diversity 11461. 11462. When the value of k increases, the effective result is ______of the equivalent curvature 11463. Flattening Bulging Sharp curvature All of these 11464. 11465. A traveling wave tube consists of 11466. Electron gun, helix and repeller Electron gun, helix and collector Electron gun, repeller and collector Buncher cavity and catcher cavity 11467. 11468. Advantage of periscope antenna in microwave 11469. Reduce tower height Minimize interference to and from other neighboring stations Shorten waveguide length Easy to install 11470. 11471. What is the cut-off frequency of a waveguide? 11472. The highest frequency the waveguide operates The lowest frequency the waveguide operates The same as the operating frequency The only frequency the waveguide operates. 11473. 11474. When the clearance above the obstruction is equal to the radii of even fresnel zones at the point of reflection. The RSL is 11475. Increased Decreased Constant Above threshold 11476. 11477. What is the wavelength of a wave in a waveguide? 11478. Greater than in free space Depends only on the waveguide dimensions and the free-space wavelength Inversely proportional to the phase velocity Inversely proportional to the group velocity 11479. 11480. The CCIR hypothetical reference circuit covering a distance of 25000 km consists of a total of how many hops? 11481. 5 10 24 54 11482. 11483. Water causes more attenuation particularly on what frequency? 11484. 20 GHz 63 GHz 183 GHz 202 GHz 11485. 11486. At what frequency does oxygen cause excessive attenuation? 11487. 60 GHz 50 GHz 40 GHz 30 GHz 11488. 11489. Which of the following is an atmospheric attenuation? 11490. Attenuation due to water vapor and oxygen Attenuation due to mist and fog Attenuation due to other gases Attenuation due to rain. 11491. 11492. A microwave system operating at the 6 GHz band is carrying 600 voice channels. What is the noise loading power in dBmO? 11493. 12.78 26.78 27.78 10.25 11494. 11495. ______is a microwave link between the down-town terminal and another out of town terminal. 11496. STL Uplink Downlink Terrestrial 11497. 11498. Attenuator is used in the traveling wave tube to 11499. Prevent oscillation Increase gain Prevent saturation All of these 11500. 11501. Is a method of diversity reception applied to reflective path to reduce fading. 11502. Frequency diversity Space diversity Polarization diversity Wavelength diversity 11503. 11504. What is the effective earth’s radius used in communications design? 11505. 4000 miles K x 4000 miles 5000 miles K x 5280 miles 11506. 11507. IF bandwidth of a radar system is inversely proportional to 11508. Pulse width Pulse interval Peak transmit power All of these 11509. 11510. EADI stands for 11511. Electronic Air Data Indicator Electronic Altitude and Distance Indicator Electronic Altitude and Director Indicator Electronic Air and Distance Indicator 11512. 11513. Which aircraft navigational system determines the time to station (TTS) or time to go (TTG)? 11514. ADF DME Timer ATC 11515. 11516. What frequency does a radio altimeter operate? 11517. 33500 kHz 43000 kHz 33500 MHz 43500 MHz 11518. 11519. What inflight system allows passengers to make telephone calls, send faxes, and computer data shop and play computer games, etc.? 11520. Inflight Satellite System Terrestrial Flight Telephone System World Airline Entertainment System Satellite Phone 11521. 11522. ADF stands for 11523. Audio Direction Findings Automatic Direction Finder Alternate Direction Finder Automatic Distance Finder 11524. 11525. RF carrier of the middle marker is modulated at ____ Hz. 11526. 1300 1400 1500 1600 11527. 11528. Which of the following is considered as the major advantage of using a helix traveling wave tube? 11529. Cheaper Less noise High power Wide bandwidth 11530. 11531. RADAR stands for 11532. Radio Distance and Ranging Radio Detection and Ranging Radio Direction and Ranging Radio Distance and Range

11533.

11534. 11535. 11536. 11537. 11538. 11539. 11540. 11541. 11542. 11543. 11544. 11545. 11546. 11547. 11548. 11549. 11550. 11551. 11552. 11553. 11554. 11555. 11556. 11557. Acoustics 11558. An instrument designed to measure a frequency-weighted value of the sound pressure level. 11559. Sound-level meter 11560. Transducer 11561. Sound pressure meter 11562. Sound analyzer 11563. A unit of noisiness related to the perceived noise level 11564. Noy 11565. Sone 11566. dB 11567. phone 11568. An agreed set of empirical curves relating octave-band osund pressure level to the center frequency of the octave bands 11569. C-message weighting curves 11570. Psophometric weighting curves 11571. Noise rating curves 11572. F1A weighting curves 11573. The frequency of free vibration 11574. Resonant frequency 11575. Natural frequency 11576. Center frequency 11577. Normal frequency 11578. The transmission of sound from one room to an adjacent room, via common walls, floors or ceilings. 11579. Flanking transmission 11580. Refraction 11581. Reflection 11582. Reverberation 11583. A measure of threshold hearing, expressed in decibels relative to a specifoed standard of normal hearing. 11584. Hearing loss 11585. Sensation level 11586. Hearing level 11587. Sound pressure level 11588. A certain machine with a slightly out-of-balance motor rotating at 1800/min is fixed on a perfectly elastic mount with a static compression of 2.50 mm. Calculate the resonant frequency of mount. 11589. 10 Hz 11590. 20 Hz 11591. 30 Hz 11592. 40 Hz 11593. 11594. Calculate the lowest resonant frequency for a brick partition 120 mm thick, 4m by 2min area with longitudinal wave velocity of 2350 m/s. (Assume that it is supported at its edges.) 11595. 10 Hz 11596. 20 Hz 11597. 30 Hz 11598. 40 Hz 11599. Velocity of sound in air. 11600. 300 m/s 11601. 330 m/s 11602. 1130 m/s 11603. 344 m/s 11604. What is the expected critical frequency for a 120 mm thick brick wall? Assume a longitudinal wave velocity in brick of 2350 m/s and that the velocity of sound in air is 330 m/s. 11605. 114.5 Hz 11606. 214.5 Hz 11607. 314.5 Hz 11608. 414.5 Hz 11609. The sound power level of a certain jet plane flying at a height of 1km is 160 dB (re10-12W). Find the maximum sound pressure level on the ground directly below the flight path assuming that the aircraft radiates sound equally in all directions. 11610. 59.1 dB 11611. 69.1 dB 11612. 79.1 dB 11613. 89.1 dB 11614. Speaker is a device that 11615. Converts sound waves into current and voltage 11616. Converts current variations into sound waves 11617. Converts elctrical energy to mechanical energy 11618. Converts elctrical energy to electromagnetic energy 11619. Which type of microphone operates on the principle that the electrical resistance of carbon granules varies as the pressure on the granules vary? 11620. Dynamic 11621. Crystal 11622. Carbon 11623. Ribbon-type 11624. Bass response is 11625. Maximum highfrequency response 11626. Emphasizing the high audio frequency 11627. Bypassing high audio frequencies 11628. Bypassing low audio frequencies 11629. Pure tone of sound used as standard on testing 11630. 1 Hz 11631. 10 Hz 11632. 100 Hz 11633. 1000 Hz 11634. ______is early reflection of sound. 11635. Echo 11636. Reverberation 11637. Pure sound 11638. Intelligible sound 11639. Noise reduction system used for film sound in movie. 11640. Dolby 11641. dBa 11642. dBx 11643. dBk 11644. What is the sound energy per unit area at right angles to the propagation direction per unit time? 11645. Loudness 11646. Coherence 11647. Sound pressure 11648. Sound intensity 11649. ______is the unit of loudness level of a sound. 11650. Sone 11651. Decibel 11652. Mel 11653. Phon 11654. ______is the average rate of transmission of sound energy in a given direction through a cross-section area of 1 sqm at right angles to the direction. 11655. Sound pressure 11656. Loudness 11657. Sound intensity 11658. Pressure variation 11659. What is the unit of pitch? 11660. Sone 11661. Phon 11662. Decibel 11663. Mel 11664. A measure of the intensity of sound in comparison to another sound intensity. 11665. Phon 11666. Decibel 11667. Pascal 11668. Watts 11669. Sound wave has two main characteristics which are 11670. Highness and loudness 11671. Tone and loudness 11672. Pitch and loudness 11673. Rarefraction and compression 11674. Which type of microphone operated by electromagnetic induction that generates an output signal voltage? 11675. Carbon 11676. Dynamic 11677. Crystal 11678. Condenser 11679. The exciter lamp in the optical sound part of a film projector draws 5 A at 10 V. How much power in watts is this light consuming? 11680. 10 watts 11681. 20 watts 11682. 40 watts 11683. 50 watts 11684. Assume the speed of sound is 1,130 ft/s. What frequency has a wavelength of 1 foot, 1.5 inches? 11685. 500 Hz 11686. 1000 Hz 11687. 1500 Hz 11688. 2000 Hz 11689. The wire must bring 100 average watts to a 4 ohms loudspeaker must safely carry what rms current? 11690. 2 A 11691. 4 A 11692. 5 A 11693. 6 A 11694. A church has an internalvolume of 90.05 ft3 (2550 m3). When it contains customary sabine sof absorption (186 metric sabines), what will be its reverberation time in seconds. 11695. 2.0 11696. 2.2 11697. 2.5 11698. 3.0 11699. If the RMs sound pressure is 5lb/ft2, what is the sound presure level? 11700. 7.6 dB 11701. 108 dB 11702. 88 dB 11703. 10 dB 11704. Speed that is faster than speed of sound. 11705. Ultrasonic 11706. Supersonic 11707. Subsonic 11708. Transonic 11709. Sound waves travel faster in water at a ______speed. 11710. 12.4 miles/sec 11711. 5000 ft/sec 11712. 186,000 ft/sec 11713. 3141 ft/sec 11714. What is the sound power from a motor car whose SPL at a distance of 7.5 m is 87 dB assuming that it radiates sound unifomly? 11715. 0.15 W 11716. 0.21 W 11717. 0.24 W 11718. 0.18 W 11719. Crest-to-crest distance along the direction to wave travel. 11720. Compression 11721. Wavelength 11722. Period 11723. Sound wave 11724. Sound intensity level is ______. 11725. 10 log I/Iref 11726. 10 log P/Pref 11727. 20 log I/Iref 11728. 30 log P/Pref 11729. Sound pressure level is ______. 11730. 20 log P/ Pref 11731. 30 log P/ Pref 11732. 10 log P/ Pref 11733. 20 log I/Iref 11734. The most important specification of loudspeakers and microphones. 11735. Frequency response 11736. Field strength 11737. Power density 11738. Gain 11739. Lowest fequency produced by a musical instrument. 11740. Midrange 11741. Harmonic 11742. Reflection 11743. Refraction 11744. Tendency of a sound energy to spread. 11745. Diffraction 11746. Rarefraction 11747. Reflection 11748. Refraction 11749. Whenwaves bend away from straight lines of travel, it is called ______. 11750. Reflection 11751. Diffraction 11752. Rarefraction 11753. Refraction 11754. Required time for any sound to decay to 60 dB. 11755. Echo time 11756. Delay time 11757. Reverberation time 11758. Transient time 11759. The intensity needed to produce an audible sound varies with ______. 11760. Frequency 11761. Noise 11762. Amplitude 11763. Tone 11764. Sound that vibrates too high for the human ear to hear (over 20 kHz). 11765. Subsonic 11766. Transonic 11767. Ultrasonic 11768. Stereo 11769. Which microphone will be damaged if exposed to high temperature above 52°C? 11770. Dynamic 11771. Crystal 11772. Ribbon 11773. Capacitor 11774. A thin springy sheet of bakelite or metal that permits the voice coil in a dynamic loudspeaker to move back and forth salong the core of its magnet. 11775. Vibrator 11776. Diaphragm 11777. Hypex 11778. Spider 11779. One hundred twenty µbars of pressure variation is equal to 11780. 120 dB SPL 11781. 57.78 dB SPL 11782. 115.56 dB SPL 11783. 41.58 dB SPL 11784. The reverberation time of a 184.2 cubic meters broadcast studio is 0.84 sec. Find the absorption effect of the materials used in metric sabines. 11785. 35.3 11786. 10.96 11787. 379.8 11788. 109.6 11789. What is the microphone characteristic that results in a boost in bassfrequencies for close microphone spacing? 11790. Field effect 11791. P.A. effect 11792. Proximity effect 11793. Reverberation 11794. What is the audio frequency range? 11795. 20 kHz to 20 MHz 11796. 0 Hz to 20 kHz 11797. 300 Hz to 400 Hz 11798. 20 Hz to 20 kHz 11799. What is the bass frequency range? 11800. 2500 Hz to 5000 Hz 11801. 5000 Hz to 10 kHz 11802. 40 kHz to 160 kHz 11803. 10 Hz to 20 kHz 11804. High frequency range of audio signals. 11805. 2500 Hz to 5000 Hz 11806. 5000 Hz to 10 kHz 11807. 10 kHz to 20 kHz 11808. 20000 Hz to 30 kHz 11809. What is the dB SPL of a voice paging in an office? 11810. 90 11811. 65 11812. 55-60 11813. 80-85 11814. What is the dB SPL of an auditorium with contemporary music? 11815. 80-95 11816. 85-90 11817. 95-100 11818. 100-105 11819. What is the church dB SPL with speech reinforcement only? 11820. 90 11821. 80-85 11822. 85-90 11823. 90-95 11824. Intensity can also be called as 11825. Volume 11826. Loudness 11827. Sharpness 11828. Strength 11829. Tje loudness of a sound depends upon the energy of motion imparted to ______molecules of the medium transmitting the sound. 11830. Transmitting 11831. Running 11832. Moving 11833. Vibrating 11834. ______is affected by the distance between the listener and the source of the sound and its intensityvaries inversely with the square of its distance. 11835. Volume 11836. Bass 11837. Treble 11838. Loudness 11839. If the distance between the listener and the source of the sound is doubled, the intensity is reduced to 11840. ½ 11841. 1/3 11842. 2/3 11843. 1/4 11844. If the distance between the listener and the source of the sound is decreased to ½ tye original amount, the intensity of the sound would be 11845. 2 times as great 11846. 3 times as great 11847. 4 times as great 11848. 5 times as great 11849. At a sensation level of 40 dB, 1000 Hz tone is 11850. 1000 mels 11851. 500 mels 11852. 2000 mels 11853. 100 mels 11854. If the sound waves are converted to electrical waves by a microphone, what is the frequency of the electric current? 11855. 3 - 30 MHz 11856. 25 – 8000 Hz 11857. 4 – 40 Hz 11858. 30 – 3000 Hz 11859. For a music lover concert “A” is 440 Hz. If a musical note one octave higher were played, it would be ______that frequency. 11860. One – half 11861. One-fourth 11862. Double 11863. Triple 11864. In a 220 Hz, if a note was played one octave lower, it would be ______. 11865. 22 Hz 11866. 27.5 Hz 11867. 440 Hz 11868. 110 Hz 11869. Much of music is generally reffered to in 11870. Harmonics 11871. Good hearing 11872. Fidelity 11873. Octaves 11874. ______is an undesired change in wave form as the signal passes through a device. 11875. Noise 11876. Vibration 11877. Distortion 11878. Harmonics 11879. Distortion enhances intelligibly when an ______is added. 11880. Equalizer 11881. Igniter 11882. Exciter 11883. Emulsifier 11884. A class of signal processors. 11885. Amplifiers 11886. Equalizers 11887. Microprocessors 11888. Exciters 11889. Half construction and internal finishes affect the final sound quality ______. 11890. poorly 11891. mildly 11892. significantly 11893. badly 11894. Positioning a loudspeaker near a wall can dramatically alter its frequency response in two distinct ways namely; 11895. Gump and dump 11896. Hump and notch 11897. Fade and gone 11898. Bad and worst 11899. The acoustics of most auditoria are very ______when the room is full compared to the empty condition. 11900. Different 11901. Similar 11902. Good 11903. Bad 11904. A ______converts acoustical energy. 11905. Electro-acoustic 11906. Microphone transducer 11907. Microphone 11908. Electric Microphone 11909. All microphone have two basic components namely, ______. 11910. Wired and body 11911. Ceramic and crystal 11912. Diaphragm and generating element 11913. Coil and magnet 11914. The kinds of generating elements are ______. 11915. Expense and fidelity 11916. Complexity and ruggedness 11917. Longevity 11918. All of these 11919. When the average absorption is greater than 0.2, ______formula is used to compute the actual reverberation time. 11920. Sabine 11921. Stephen and Bate 11922. Norris-Eyring 11923. Notch 11924. At room temperature, what is the velocity of sound in meters/seconds? 11925. 348.03 cm/s 11926. 980 cm/s 11927. 980 m/s 11928. 341.8 m/s 11929. Calculate the velocity of sound in ft./sec. if the temperature is 1490C? 11930. 1530.03 ft/sec 11931. 1320 ft/sec 11932. 1357.03 ft/sec 11933. 1920.345 ft/sec 11934. The wavelength of a sound of 20 kHz frequency is 11935. 16.5 m 11936. 16.5 cm 11937. 16.5 mm 11938. 16.5 um 11939. The radio of frequencies is termed 11940. Octave 11941. Interval 11942. Harmonics 11943. Masking 11944. What is the increase in sound pressure level in dB, if the pressure is doubled? 11945. 2 dB 11946. 3 dB 11947. 6 dB 11948. 4 dB 11949. A term which is subjected but dependent mainly on frequency and also affected by intensity, 11950. Timbre 11951. Quality 11952. Frequency 11953. Pitch 11954. An effect that occurs in the ear where a louder sound can reduce or even stop the nerve voltage generated by a weaker sound. 11955. Piezoelectric effect 11956. Skin effect 11957. Lasing 11958. Masking 11959. For computation of ideal reverberation time, which formula is applicable? 11960. Sabine 11961. Stephen and Bate 11962. Norris-Eyring 11963. Notch 11964. The ______of the sound is a subjective effect which is a function of the ear and brain. 11965. Pitch 11966. Frequency 11967. Timbre 11968. Loudness 11969. Define as the time taken from the intensity of sound energy in the room to drop to one millionth of its initial value. 11970. Reverberation time 11971. Transit time 11972. Decaying time 11973. Response time 11974. ______is the sound energy per unit area at right angles of the propagation direction, per unit time. 11975. Loudness 11976. Coherence 11977. Sound stress 11978. Sound intensity 11979. One octave above 600 Hz is 11980. 601 Hz 11981. 800 Hz 11982. 1400 Hz 11983. 1200 Hz 11984. A car horn outdoors produces a sound intensity level of 90 dB at 10 m away. At this distance, what is the sound power in watt? 11985. 0.63 11986. 1.26 11987. 0.315 11988. 0.56 x 10-6 11989. The unit of loudness level 11990. Sone 11991. dB 11992. Mel 11993. Phon 11994. Consist of a rapid succession of noticeable echoes. 11995. Rarefaction 11996. Refraction 11997. Reflection 11998. Flutter echo 11999. Laid the foundations of acoustic theory of buildings. 12000. Charles H. Townes 12001. W.C Sabine 12002. A. Javin 12003. Stephen and Bate 12004. An aural sensation by pressure variations in the air which are always produced by some source of vibrations. 12005. Music 12006. Sound 12007. Disturbance 12008. Speech 12009. Considered to be the threshold of hearing. 12010. 10-12 W/cm2 12011. 10-16 W/m2 12012. 10-13 W/m2 12013. 10-12 W/m2 12014. The average absorption for a person is 12015. 5.7 units 12016. 4.7 units 12017. 6.7 units 12018. 3.7 units 12019. The number of vibration or pressure fluctuations per seconds. 12020. Frequency 12021. Timbre 12022. Quality 12023. Pitch 12024. Defined as the average rate of transmission of sound energy in a given direction through a cross-sectional area of 1 m2 at right angles to the direction. 12025. Sound pressure 12026. Loudness 12027. Sound intensity 12028. Pressure variation 12029. What is the sound pressure level (SPL) of a sound having a RMS pressure of 200 N/m2? 12030. 150 dB 12031. 140 dB 12032. 170 dB 12033. 160 dB 12034. The minimum sound intensity that can be heard is termed 12035. Threshold of feeling 12036. Threshold of pain 12037. Threshold of sensation 12038. Threshold of hearing 12039. What is the intensity of the sound whose RMS pressure is 200 N/m2? 12040. 96.9 W/m2 12041. 97.9 W/m2 12042. 95.9 W/m2 12043. 94.9 W/m2 12044. The unit of pitch. sone pitch dB Mel 12045. What is the increase in sound pressure level in dB, if the intensity is doubled? 2 dB 3 dB 4 dB 6 dB 12046. The velocity of sound is considered to be constant at ______for the purpose of acoustics. 300 m/s 330 mm/s 330 µm/s 330 cm/s 12047. 12048. 12049. 12050. 12051. 12052. 12053. 12054. 12055. 12056. 12057. 12058. 12059. 12060. 12061. 12062. 12063. 12064. 12065. 12066. 12067. 12068. 12069. 12070. 12071. Radiation and wave propagation 12072. ______is the amount of voltage induced in wave by an electro magnetic wave. receive voltage magnetic induction field strength power density 12073. An electro magnetic wave consists of ______. both electric and magnetic fields. an electric field only a magnetic field only non-magnetic field only 12074. What is the lowest layer of the ionosphere? F1 F2 E D 12075. Who profounded electro magnetic radiation theory? Sir Edward Appleton James Clerk Maxwell Christian Huygens Sir Isaac Newton 12076. The D, E and F layers are known as ______. Mark – space Layers Davinson- Miller Layers Kennely – Heaviside Layers Appleton Layers 12077. Different grouping of the electromagnetic spectrum. band bandwidth channel group 12078. What is the relation in degrees of the electric and magnetic fields in an electromagnetic wave? 180 degrees 90 degrees 270 degrees 45 degrees 12079. A changing electric field gives rise to ______. a magnetic field sound field electromagnetic waves near and far fields 12080. Frequencies in the UHF range propagate by means of ground waves sky waves surface waves space waves 12081. In electromagnetic waves, polarization ______. is caused by reflection is due to the transverse nature of the waves results from the longitudinal nature of the waves is always vertical in an isotropic medium 12082. Electromagnetic Waves are refracted when they ______. pass into a medium of different dielectric constants are polarized at right angles to the direction of propagation encounter a perfectly conducting surface pass through a small slot in a conducting plane 12083. What is the highest layer of the atmosphere? ionosphere stratosphere troposphere ozone layer 12084. What is the thickest layer of the ionosphere? F2 F1 D E 12085. Effective Earth radius to true earth radius ratio. index of refraction K factor Fresnel zone path profile 12086. Fading due to interference between direct and reflected rays. atmospheric-mutipath Fresnel zone reflection-multi path Rayleigh fading 12087. The layer that reflects very low frequency waves and absorbs medium frequency waves. D Layer E Layer F1 Layer F2 Layer 12088. What layer is used for high-frequency day time propagation? D Layer E Layer F1 Layer F2 Layer 12089. What is the highest frequency that can be sent straight upward and be returned to earth? MUF skip frequency critical frequency gyro frequency 12090. High frequency range is from? 0.3 to 3MHz 3 to 30MHz 30 to 300MHz 3to 30MHz 12091. Medium frequency range is from 0.01 to 0.03 MHz 0.03 to 0.3MHz 0.3 to 3MHz 3 to 30 MHz 12092. In tropospheric scatter propagation, the attenuation is dependent on scatter angle take-off angle antenna size the troposphere 12093. If the transmitter power remains constant, an increase in the frequency of the sky wave will lengthen the skip distance increase the range of the ground wave reduce the length of the skip distance have no effect on the ground wave range 12094. What is the unit of electric field strength? volts per square meter volt per square cm volts per meter milivolt per watt 12095. Velocity of a radio wave in free space. 186,000 miles per sec 300x106 meters per sec 162,000 nautical mile per sec all of the above 12096. Refers to the direction of the electric field vector in space. polarization directivity radiation ERP 12097. An TEM wave whose polarization rotates. vertically polarized omnidirectional horizontally polarized circularly polarized 12098. velocity of light in free space 300x106m/s 300x106km/s 186,000km/s 186,000m/s 12099. What is the effective radiated power of a repeater with 200W transmitter power output, 4dB feed line loss, 4dB duplxer and circulator loss, and 10dB feed line antenna gain? 2000W 12100. b. 126W 12101. c. 317W 12102. d. 260W 12103. Radio wave that is far from its sources is called Plane wave isotrpic wave vertical wave horizontal wave 12104. Light goes from medium A to medium B at angle of incidence of 40 degrees. The angle of refraction is 30 degrees. The speed of light in B is the same as that in A is greater than that in A maybe any of these, depending on the specific medium is less than that in A 12105. In a vacuum, the speed of an electromagnetic wave depends on its constant depends on its wavelength depends on its electric and magnetic fields is a universal constant 12106. The depth of an object submerged in a transparent liquid always seems more that its actual depth 12107. b may seem less or more than its actual depth, depending on the object 12108. c. always seems less than its actual depth 12109. d. may seem less or more than its actual depth, depending on the transparent liquid 12110. What is a wave front? a voltage pulse in a conductor a current in a conductor a fixed point in an electromagnetic wave a voltage pulse across a resistor 12111. VHF ship station transmitters must have the capability of reducing carrier power to 1W 10W 25W 50W 12112. Most of the effects an electro magnetic wave produces when it interacts with matter are due to its magnetic field speed frequency electric field 12113. A mobile receiver experiences “dead” areas of reception as a result of atmospheric absorption tropospheric scatter sporadic E shading of the RF signal by hills and trees 12114. When the electric field is perpendicular in the surface of the earth, what is the polarization of the TEM wave? elliptical vertical horizontal circular 12115. When the magnetic field is perpendicular to the surface of the earth, what is the polarization of the TEM wave? circular horizontal vertical elliptical 12116. When the magnetic field is parallel to the surface of the earth, what is the polarization of the TEM wave? elliptical horizontal vertical circular 12117. What are the two interrelated fields considered to make up an electromagnetic wave an electric field and a current field an electric field and voltage field an electric field and a magnetic field a voltage and current fields 12118. How does the bandwidth of the transmitted signal affect selective fading? it is more pronounced at narrow bandwidths it is equally pronounced at both narrow and wide bandwidths it is more pronounced at wide bandwidths the receiver bandwidth determines the selective fading 12119. A wide-bandwidth communications systems in which the RF carrier varies according to some predetermined sequence. amplitude compandored single sideband SITOR spread spectrum communication time-domain frequency modulation 12120. A changing magnetic field gives rise to sound field magnetic field electric field nothing in particular 12121. When a space-wave signal passes over a mountain ridge, a small part of the signal is diffracted down the far side of the mountain. This phenomenon is called discontinuity scattering troposheric ducting knife-edge diffraction space-wave refraction 12122. The index of refraction of a material medium is greater than 1 is less than 1 is equal to 1 maybe any of the bove 12123. At what speed do electromagnetic waves travel in free space? approximately 468 million meters per second approximately 186300 ft/s approximately 300 million m/s approximately 300 million miles/s 12124. What is the effective earth radius when surface refractivity, and N equals 300? 6370km 12125. b.7270km 12126. c.7950km 12127. d. 8500km 12128. If N = 250, what is the earth radius K-factor? 1.23 1.29 1.33 1.32 12129. Electric field that lies in a plane perpendicular to the earths surface vertical polarization horizontal polarization circular polarization elliptical polarization 12130. Electric field that lies in a plane parallel to the earth’s surface vertical polarization horizontal polarization circular polarization elliptical polarization 12131. Indicate which one of the following terms applies to trposcatter propagation SIDs fading atmospheric storms faraday rotation 12132. VLF waves are used for some types of services because of the low power required 12133. b the transmitting antennas are of convenient size 12134. c. they are very reliable 12135. d. they penetrate the ionosphere easily 12136. Indicate which of the following frequencies cannot be used for reliable beyond- the-horizon terrestrial communications without repeaters 20KHz 15MHz 900MHz 12GHz 12137. High-frequency waves are absorbed by the F2 layer reflected by the D leayer capable of use for long-distance communications on the moon affected nby the solar cycle 12138. Distances near the skip distance should be used for sky-wave propagation to avaoid tilting to prevent sky-wave and upper ray interference to avoid the faraday effect so as not to exceed the critical frequency 12139. A ship-to-ship communications system is plague by fading. The best solution seems to be the use of a more directional antenna a broadband antenna frequency diversity space diversity 12140. A range of microwave frequencies more easily passed by the atmosphere than are the others is called a window critical frequency gyro frequency range resonance in the atmosphere 12141. frequencies in the UHF range normally propagate by means of ground waves. sky waves surface waves space waves 12142. Tropospheric scatter is used with frequencies in the following range HF VHF UHF VLF 12143. The ground wave eventually disappears as one moves away from the transmitter because of interference from the sky wave loss of line – of – sight conditions maximum single-hop distance limitation tilting 12144. in electromagnetic waves, polarization means the physical orientation of magnetic field in space the physical orientation of electric field in space ionization the presence of positive and negative ions 12145. an electromagnetic waves travel in free space, only one of the following can happen to them. absorption attenuation refraction reflection 12146. the absorption of a radio waves by the atmosphere depends on their frequency their distance from the transmitter the polarization of the waves the polarization of the atmosphere 12147. diffraction of electromagnetic waves is caused by reflections from the ground arises only with spherical wavefronts will occur when the waves pass through a large slot may occur around the edge of a sharp object 12148. 12149. In an electromagnetic wave the electric field is 12150. Parallel to both magnetic field and the wave direction 12151. Perpendicular to both the magnetic field and the wave direction 12152. Parallel to the magnetic field and perpendicular to the wave direction 12153. Perpendicular to the magnetic field and parallel to the wave direction 12154. The highest frequencies are found in 12155. X-rays 12156. Radio waves 12157. Ultraviolet rays 12158. Radar waves 12159. Electromagnetic waves transport 12160. Wavelength 12161. Charge 12162. Frequency 12163. Energy 12164. The ionosphere is a region of ionized gas in the upper atmosphere. The ionosphere is responsible for The blue color of the sky Rainbows Long distance radio communication The ability of satellites to orbit the earth 12165. Light of which the following colors has the shortest wavelength Red Yellow Blue Green 12166. The quality in sound that corresponds to color in light is Amplitude Resonance Waveform Pitch 12167. All real images Are erect Can appear on screen Are inverted Cannot appear on a screen 12168. When a beam of light enters one medium from another, a quality that never changes is its Direction Frequency Speed Wavelength 12169. Relative to the angle of incidence, the angle of refraction Is smaller Is larger Is the same Either A or B above 12170. A light ray enters one medium from another along the normal. The angle of refraction is 0 90 degrees Equal to the critical angle Dependent on the indexes of refraction of the two media 12171. What layer aids MF surface-wave propagation a little and reflects some HF waves in daytime? E layer D layer F1 layer F2 layer 12172. Dispersion is the term used to describe The splitting of white light into its component colors in regraction The propagation of light in straight lines The bending of a beam of light when it goes from one medium to another The bending of a beam of light when it strikes a mirror 12173. The depth of an objects submerged in a transparent liquid Always seems less than its actual depth Always seems more than its actual depth May seems more than its actual depth, depending on the index of refraction of the liquid May seem less or more than its actual depth depending on the angle of view 12174. Total internal reflection can occur when light passes from one medium to another That has a lower index of refraction That has a larger index of refraction That has the same index of refraction At less than the critical angle 12175. When the light ray approaches a glass-air interface from the glass side at the critical angle, the angle of refraction is 0 90 degrees 45 degrees Equal to the angle of incidence 12176. The brightness of light source is called its luminous intensity , whose unit is Candela Lux Lumen Footcandle 12177. Luminous efficiency is least for a Low-wattage light bulb Mercury vapour lamp High-wattage light bulb Fluorescent tube 12178. The minimum illumination recommended for reading is 8000 cd 8000 lx 8000 lm 800W 12179. Light enters a glass plate whose index of refraction is 1.6 at an angle of incidence of 30 degrees . the angle of refraction is 18 degrees 48 degrees 19 degrees 53 degrees 12180. Light leaves a slab of transparent material whose index of refraction is 2 at an angle of refraction of 0 degrees. The angle of incidence is 0 degrees 45 degrees 30 degrees 90 degrees 12181. Light enters a glass plate at an angle of incidence of 40 degrees and is refracted at an angle refraction of 25 degrees. The index refraction of the glass is 0.625 1.52 0.66 1.6 12182. An underwater swimmer shines a flash light beam upward at an angle of incidence of 40 degrees. The angle of refraction is 60 degrees. The index of refraction of water is 0.67 1.3 0.74 1.5 12183. The critical angle of incidence for light going from crown glass (n=1.5) to ice (n=1.3) is 12 degrees 50 degrees 42 degrees 60 degrees 12184. The solid angle subtended by a hemisphere about its ceter is π/2 sr 2 π sr π sr depends on the radius of the hemisphere 12185. the luminous flux emitted by a 60-cd isotropic light source is concentrated on an area of 0.5m2. the illumination of the area is 9.6 lx 377 lx 120 lx 1508 lx 12186. Microwave signals propagate by way of the Direct wave Sky wave Surface wave Standing wave 12187. The ionosphere causes radio signals to be Diffused Absorbed Refracted Reflected 12188. Ground wave communications is most effective in what frequency range? 300KHz to 3MHz 3 to 30 MHz 30 to 300MHz Above 300MHz 12189. The ionosphere has its greatest effect on signals in what frequency range? 300KHz to 3MHz 3 to 30 MHz 30 to 300MHz Above 300MHz 12190. The type of radio wave responsible for long distance communications by multiple skips is the Groud wave Direct wave Surface wave Sky wave 12191. Line of sight communications is not a factor in which frequency range? VHF UHF HF Microwave 12192. A microwave-transmitting antenna is 550ft high. The receiving antenna is 200ft high. The minimum transmission distance is 20 mi 33.2 mi 38.7 mi 53.2 mi 12193. To increase the transmission distance of UHF signal, which of the following should be done? Increase antenna gain Increase antenna height Increase transmitter power Increase receiver sensitivity 12194. States that power density is inversely proportional to the distance from its source. Principle of reciprocity Inverse square law Huygen’s Princple Faraday’s law 12195. gets in contact with the ionosphere and reflected by it. Space wave Sky wave Surface wave Satellite wave 12196. Highest layer in the ionosphere F1 D F2 E 12197. Next lowest layer in the ionosphere. D E F1 F2 12198. What is the primary cause of ionization in the atmosphere? Sun spot Cosmic rays Galactic disturbance Ultraviolet radiation 12199. Which layer does not disappear at night? D E F1 F2 12200. Which of the following uses surface wave propagation? ELF VLF MF All of these 12201. The ability of the ionosphere to reflect a radio wave back to the earth is determined by Operating frequency Ion density Angle of incidence All of these 12202. Highest frequency that can be used for skywave propagation between two given points on earth. Critical frequency MUF Cut –off frequency UHF 12203. The shortest distance measured along the earth’s surface that a skywave is returned to earth. MUF Quarter-wavelength Skip distance Skip zone 12204. Fluctuation in the signal strength at the receiver. Interference Fading Tracking Variable frequency 12205. Two or more antennas are used separated by several wavelengths Space diversity Frequency diversity Hybrid diversity Polarization diversity 12206. Two or more receivers are used using a single antenna. Space diversity Frequency diversity Hybrid diversity Polarization diversity 12207. One of the following is not a cause of fading. Interference between upper and lower rays of a sky wave. Skywaves arriving at different number of hops Interference due to ground reflected wave and skywave Diversity 12208. What do you call the gigantic emissions of hydrogen from the sun? Solar flares SIDs Kennely-Heaviside Sun spots 12209. Sudden ionospheric disturbance Solar flares SIDs Sun spots Intertropical convergence 12210. A means beyond the line of sight propagation of UHF signals. Microwave propagation Space wave propagation Troposcatter propagation Surface wave propagation 12211. Two directional antennas are pointed so that their beams intersect in the troposphere. Skywave Surface wave Microwave Troposcatter 12212. Super refraction. Ducting Trposcatter Skywave Space wave 12213. A layer of warm air trapped above cooler air Troposphere SID Duct Huygen’s principle 12214. Corresponds to voltage Electric field Magnetic field Gyro Direction of propagation 12215. Absence of reception Skip distance Maximum usable Shadow zone Twilight zone 12216. Each point in a spherical waveform maybe a source of a secondary spherical wavefront. Senll’s law Huygen’s principle Rayleigh’s principle De Morgan’s theore, 12217. Ducting occurs in which region of the atmosphere? Stratosphere Troposphere Ionosphere Ozone layer 12218. When is the E region most ionized? At midday At midnight At duck At dawn 12219. Transequatorial propagation is best during Night time Afternoon or early evening Noontime Morning 12220. Which of the following is most affected by knife-edge refraction? Very high and ultra high frequencies High frequencies Medium frequency Low frequency 12221. Which ionosphere layer has an average height of 225km at night? D layer E layer F1 layer F2 layer 12222. 12223. 12224. 12225. 12226. 12227. 12228. 12229. 12230. 12231. 12232. 12233. 12234. 12235. 12236. 12237. 12238. Transmission Fundamentals 12239. What is the opposition to the transfer of energy which is considered the dominant characteristic of a cable or circuit that emanates from its physical structure? 12240. Conductance 12241. Resistance 12242. Reactance 12243. Impedance 12244. When load impedance equals to Zo of the line, it means that the load _____ all the power. 12245. reflects 12246. absorbs 12247. attenuates 12248. radiates 12249. impedance matching ratio of a coax balun. 12250. 1:4 12251. 4:1 12252. 2:1 12253. 3:2 12254. Which stands for dB relative level? 12255. dBrn 12256. dBa 12257. dBr 12258. dBx 12259. Standard test tone used for audio measurement. 12260. 800 Hz 12261. 300 Hz 12262. 100 Hz 12263. 1000 Hz 12264. When VSWR is equal to zero, this means 12265. that no power is applied 12266. that the load is purely resistive 12267. that the load is a pure reactance 12268. that the load is opened 12269. ______is the ratio of reflected voltage to the forward travelling voltage. 12270. SWR 12271. VSWR 12272. Reflection coefficient 12273. ISWR 12274. Transmission line must be matched to the load to ______. 12275. transfer maximum voltage to the load 12276. transfer maximum power to the load 12277. reduce the load current 12278. transfer maximum current to the load 12279. Which indicate the relative energy loss in a capacitor? 12280. Quality factor 12281. Reactive factor 12282. Dissipation factor 12283. Power factor 12284. What is the standard test tone? 12285. 0 dB 12286. 0 dBW 12287. 0 dBm 12288. 0 dBrn 12289. The energy that neither radiated into space nor completely transmitted. 12290. Reflected waves 12291. Captured waves 12292. Incident waves 12293. Standing waves 12294. Micron is equal to ______meter. 12295. 10-10 12296. 10-9 12297. 10-6 12298. 10-3 12299. 1 Angstrom (A) is equal to ______. 12300. 10-3 micron 12301. 10-10 m 12302. 10-6 micron 12303. 10-6 m 12304. Why is it impossible to use a waveguide at low radio frequencies? 12305. Because of the size of the waveguide 12306. Due to severe attenuation 12307. Due to too much radiation 12308. All of these 12309. ______is the transmission and reception of information. 12310. Modulation 12311. Communications 12312. Radiation 12313. Emission 12314. What is the loss of the circuit in dB if the power ration of output to input is 0.01? 12315. 20 12316. -20 12317. 40 12318. -40 12319. Transmission lines are either balanced or unbalanced with respect to 12320. Negative terminal 12321. Reference 12322. Ground 12323. Positive terminal 12324. The standing wave ratio is equal to ______if the load is properly matched with the transmission line. 12325. Infinity 12326. 0 12327. -1 12328. 1 12329. ______is the advantage of the balanced transmission line compared to unbalanced line. 12330. Low attenuation 12331. Easy installation 12332. Low radiation loss 12333. Tensile strength 12334. ______is the method of determining the bandwidth of any processing system. 12335. Fourier series 12336. Spectral analysis 12337. Frequency analysis 12338. Bandwidth analysis 12339. What causes the attenuation present in a waveguide? 12340. The air dielectric filling the guide 12341. The coating of silver inside 12342. Losses in the conducting walls of the guide 12343. Radiation loss 12344. A device that converts a balanced line to an unbalanced line of a transmission line. 12345. Hybrid 12346. Stub 12347. Directional coupler 12348. Balun 12349. What is the approximate line impedance of a parallel-strip line spaced 1 cm apart with the length of 50 cm? 12350. 10 ohms 12351. 15 ohms 12352. 18 ohms 12353. 23 ohms 12354. What is the average power rating of RG-58 C/u? 12355. 25 W 12356. 50 W 12357. 75 W 12358. 200 W 12359. A coaxial cable used for high temperatures. 12360. RG-58C 12361. RG-11A 12362. RG-213 12363. RG-211 12364. If you have available number of power amplifiers with a gain of 100 each, how many such amplifiers do you need to cascade to give an overall gain of 60dB? 12365. 2 12366. 3 12367. 4 12368. 5 12369. You are measuring noise in a voice channel at a -4 dB test point level, the meter reads -73 dBm, convert the reading into dBrnCO. 12370. 12 12371. 16 12372. 18 12373. 21 12374. The velocity factor for a transmission line 12375. depends on the dielectric constant of the material used 12376. increases the velocity along the transmission line 12377. is governed by the skin effect 12378. is higher for a solid dielectric than for air 12379. Impedance inversion can be obtained by 12380. a short-circuited stub 12381. an open-circuited stub 12382. a quarter-wave line 12383. a half-wave line 12384. Transmission lines when connected to antennas have 12385. capacitive load 12386. resistive load whose resistance is greater than the characteristic impedance of the line 12387. resistive load whose resistance is less than the characteristic impedance of the line 12388. resistive load at the resonant frequency 12389. One of the following is not a bounded media. 12390. Coaxial line 12391. Two-wire line 12392. Waveguide 12393. Ocean 12394. The impedance measured at the input of the transmission line when its length is infinite. 12395. Input impedance 12396. Open circuit impedance 12397. Characteristic impedance 12398. Short circuit impedance 12399. The following are considered primary line constants except 12400. conductance 12401. resistance 12402. capacitance 12403. complex propagation constant 12404. The dielectric constants of materials commonly used in transmission lines range from about 12405. 1.2 to 2.8 12406. 2.8 to 3.5 12407. 3.5 to 5.2 12408. 1.0 to 1.2 12409. Typically, the velocity factor (VF) of the materials used in transmission lines range from 12410. 0.6 to 0.9 12411. 0.1 to 0.5 12412. 1.0 to 0.9 12413. 0.6 to 0.8 12414. For an air dielectric two-wire line, the minimum characteristic impedance value is 12415. 85 ohms 12416. 85 ohms 12417. 90 ohms 12418. 88 ohms 12419. When a quarter-wave section transmission line is terminated by a short circuit and is connected to an RF source at the other end, its input impedance is 12420. inductive 12421. capacitive 12422. resistive 12423. equivalent to a parallel resonant LC circuit 12424. A transmitter operating at 30 MHz with 4 W output is connected via 10 m of RG- 8A/u cable to an antenna that has an input resistance of 300 ohms. Find the reflection coefficient. 12425. 0.71 12426. 0.77 12427. 0.97 12428. 0.76 12429. A quarter wave transformer is connected to a parallel wire line in order to match the line to a load of 1000 ohms. The transformer has a characteristic impedance of 316.23 ohms. The distance between centers is 4 inches. What is the percentage reduction in the diameter of the line? 12430. 85% 12431. 83% 12432. 86% 12433. 90% 12434. The concept used to make one Smith chart universal is called 12435. ionization 12436. normalization 12437. rationalization 12438. termination 12439. What are the basic elements of communications system? 12440. Source, transmission channel, transmitter 12441. Transmitter, receiver, transmission channel 12442. Information, transmission channel, receiver 12443. Sender and receiver 12444. ______is the transmission of printed material over telephone lines. 12445. Internet 12446. Data communication 12447. Telegraphy 12448. Facsimile 12449. ______is a continuous tone generated by the combination of two frequencies of 350 Hz and 440 Hz used in telephone sets. 12450. DC tone 12451. Ringing tone 12452. Dial tone 12453. Call waiting tone 12454. ______are unidirectional amplifiers having 20-25 decibel gain that are placed about 75 km apart used to compensate for losses along the telephone line. 12455. VF repeaters 12456. Loading coils 12457. Loop extenders 12458. Echo suppressors 12459. ______is a component in the telephone set that has the primary function of interfacing the handset to the local loop. 12460. Resistor 12461. Capacitor 12462. Varistor 12463. Induction coil 12464. Pulse dialing has ______rate. 12465. 20 pulses/min 12466. 10 pulses/min 12467. 10 pulses/sec 12468. 80 pulses/sec 12469. ______is a telephone wire that connects two central offices. 12470. 2-wire circuit 12471. Trunk line 12472. Leased line 12473. Private line 12474. The central switching office coordinating element for all cell sites that has cellular processor and a cellular switch. It interfaces with telephone company zone offices, control call processing and handle billing activities. 12475. MTSO 12476. Cell site 12477. PTSN 12478. Trunk line 12479. ______in a cellular system performs radio-related functions for cellular site. 12480. Switching system 12481. Base station 12482. Operation and support system 12483. Mobile station 12484. A technology used to increase the capacity of a mobile phone system. 12485. Frequency re-use 12486. Cell splitting 12487. TDM 12488. FDM 12489. If the grade of service of a telephone system indicated P = 0.05, what does it mean? 12490. Completed calls of 5% 12491. Lost calls of 5% 12492. Lost calls of 95% 12493. Lost calls of 105% 12494. ______is the Out-of-Band signaling between Toll Central Offices (Bell System Standard). 12495. 3, 825 Hz 12496. 3, 700 Hz 12497. 2, 600 Hz 12498. 800 Hz 12499. In a telephone system, the customer’s telephone directory numbering is from 000 to 999, what is the capacity of a telephone system numbering from 000 to 999? 12500. 100 lines 12501. 1000 lines 12502. 10, 000 lines 12503. 100, 000 lines 12504. If the SWR is infinite, what type of load transmission line has? 12505. Purely reactive 12506. Purely resistive 12507. Purely capacitive 12508. Purely inductive 12509. Not more than ______digits make up an international telephone number as recommended by CCITT REC. E. 161. 12510. 8 12511. 10 12512. 11 12513. 12 12514. One (1) Erlang is equal to ______. 12515. 360 CCS 12516. 36 CCS 12517. 3.6 CCS 12518. 100 CCS 12519. Standard tariff for flat rate telephone service beyond the normal flat rate in that area. 12520. WATS 12521. OTLP 12522. TIP 12523. DTWX 12524. The standard analog telephone channel bandwidth. 12525. 300-3400 Hz 12526. 1200 Hz 12527. 200-3200 Hz 12528. 300-3000 Hz 12529. Type of switching in which a pair of wire from the telephone set terminates in a jack and the switch is supervised by an operator. 12530. Crossbar switching 12531. Manual switching 12532. Electronic switching 12533. Step-by-step switching 12534. Every time when the telephone is idle, the handset is in the ______state. 12535. On-hook 12536. Off-hook 12537. Busy 12538. Spare 12539. ______is a component in the telephone set that has the primary function of compensating for the local loop length. 12540. Resistor 12541. Varistor 12542. Capacitor 12543. Induction coil 12544. What kind of receiver is used in conventional telephone handset? 12545. Carbon 12546. Electromagnetic 12547. Ceramic 12548. Capacitor 12549. A voice-grade circuit using the PTN ha an ideal passband of 12550. 0 to 4 Hz 12551. 0 to 4 MHz 12552. 0 to 4 kHz 12553. 0 to 4 GHz 12554. ______is the minimum-quality circuit available using the PTN. 12555. Basic voice grade (VG) 12556. Basic voice channel (VC) 12557. Basic voice band (VB) 12558. Basic telephone channel 12559. Direct distance dialing (DDD) network is called 12560. Private-line network 12561. PT network 12562. Dial-up network 12563. Trunk network 12564. What is the advantage of sidetone? 12565. Transmission efficiency is increased 12566. Speaker increases his voice resulting in a strengthened signal 12567. No dissipation of energy in the balancing network 12568. Assure the customer that the telephone is working 12569. ______is a special service circuit connecting two private branch exchanges (PBX). 12570. Phantom line 12571. Tie trunk 12572. Tandem trunk 12573. Private line 12574. The published rates, regulation, and descriptions governing the provision of communications service for public use. 12575. Toll rate 12576. Tariff 12577. Bulk billing 12578. Detailed billing 12579. What is the power loss of a telephone hybrid? 12580. 1 dB 12581. 2 dB 12582. 3 dB 12583. 6 dB 12584. Telephone channel has a band-pass characteristic occupying the frequency range of ______. 12585. 300-400 Hz 12586. 300-3400 Hz 12587. 300-3000 Hz 12588. 300-2700 Hz 12589. The first Strowger step-by-step switch was used in ______. 12590. 1875 12591. 1890 12592. 1897 12593. 1913 12594. What is the phase delay of an 800 Hz voice signal if the phase shift is 15 degrees? 12595. 52usec 12596. 1.25usec 12597. 83.33usec 12598. 26usec 12599. What is the CCITT recommendation for a preparation of loss plan, a variable loss plans and a fixed loss plan? 12600. G. 133 12601. G. 141 12602. G. 132 12603. G. 122 12604. What is the diameter of a copper wire to be used in a 16 km loop with a dc loop resistance of 100 ohms/km? 12605. 0.838 mm 12606. 0.465 mm 12607. 1.626 mm 12608. 2.159 mm 12609. What kind of cell is appropriate for load management, fast moving mobiles and low-usage areas? 12610. Pico cells 12611. Micro cells 12612. Nano cells 12613. Umbrella cells 12614. In cellular networks, standard base station antennas are placed by ______. 12615. adaptive array 12616. flat plate antenna 12617. dipole array 12618. focused antenna 12619. What is the basis of the first generation wireless local loop? 12620. Digital cellular technology 12621. Analogue cellular technology 12622. PSTN 12623. AMPS technology 12624. When the calling party hears a “busy” tone on his telephone, the call is considered 12625. lost 12626. disconnected 12627. completed 12628. incomplete 12629. Short-circuited stubs are preferred to open circuited stubs because the latter are 12630. more difficult to make and connect 12631. made of a transmission line with a different characteristic impedance 12632. liable to radiate 12633. incapable of giving a full range of reactances 12634. What is the ratio of the reflected voltage to the incident voltage? 12635. VSWR 12636. ISWR 12637. SWR 12638. Coefficient of reflection 12639. One method of determining antenna impedance. 12640. Sub matching 12641. Trial and error 12642. Smith chart 12643. Quarter-wave matching 12644. ______is a single conductor running from the transmitter to the antenna. 12645. Single-wire line 12646. Microstrip 12647. Twin-lead 12648. Coaxial line 12649. Coaxial cable impedance is typically ______. 12650. 150 to 300 ohms 12651. 50 to 75 ohms 12652. 30 to 45 ohms 12653. 300 to 600 ohms 12654. Waveguide becomes compulsory above what frequencies? 12655. Above 3 GHz 12656. Above 10 kHz 12657. At 300 MHz 12658. Above 10 GHz 12659. Nominal voice channel bandwidth is ______. 12660. 20 to 30 kHz 12661. 0 to 3 kHz 12662. 4 kHz 12663. 55 kHz above 12664. Echo suppressors are used on all communications system when the round trip propagation time exceeds ______. 12665. 50 ms 12666. 30 ms 12667. 100 ms 12668. 1 ms 12669. A radio transmission line of 300 ohms impedance is to be connected to an antenna having an input impedance of 150 ohms. What is the impedance of a quarter-wave matching line? 12670. 212 ohms 12671. 250 ohms 12672. 200 ohms 12673. 150 ohms 12674. Quarter-wavelength line is used as ______. 12675. impedance transformer 12676. lecher line 12677. transmission line 12678. harmonic suppressor 12679. The transmission lines which can convey electromagnetic waves only in higher modes is usually called 12680. coaxial cable 12681. waveguide 12682. power lines 12683. twisted wire of telephone line 12684. Why is nitrogen gas sometimes used in waveguide? 12685. To increase the distributed capacitance 12686. To keep the waveguide dry 12687. To reduce the skin effect at the walls of the guide 12688. To raise the guide’s wave impedance 12689. The apparent speed of propagation along a waveguide based on the distance between wavefronts along the walls of the guide is called 12690. group velocity 12691. phae velocity 12692. normal velocity 12693. abnormal velocity 12694. How do you couple in and out of a waveguide? 12695. Wrap a coil of wire around one end of the waveguide 12696. Insertion of an E-probe into the waveguide 12697. Insertion of an H-loop into the waveguide 12698. Both B and C 12699. A rectangular waveguide is operating in the dominant TE10 mode. The associated flux lines are established 12700. transversely across the narrow dimension of the waveguide 12701. transversely across the wide dimension of the waveguide 12702. in the metal walls parallel to the direction of propagation 12703. in the metal walls perpendicular to the direction of propagation 12704. For dominant mode of a rectangular waveguide, the distance between two instantaneous consecutive positions of maximum field intensity (in a direction parallel to the walls of the waveguide) is referred to as half of the 12705. free-space wavelength 12706. cutoff wavelength in the wide dimension 12707. guide wavelength 12708. group wavelength 12709. The guide wavelength, in a rectangular waveguide is 12710. equal to the free-space wavelength at the cutoff frequency 12711. equal to the free-space wavelength for the same signal frequency 12712. less than the free-space wavelength at the cut-off frequency 12713. greater than the free-space wavelength at the same signal frequency 12714. Using the TE10 mode, microwave power can only be transmitted in free rectangular guide provided 12715. the wider dimension is less than one-half of the wavelength in free space 12716. the narrow dimension is less than one-quarter of the wavelength in free space 12717. the wide dimension is greater than one-half of the guide wavelength 12718. the wide dimension is greater than one-half of the wavelength in free space 12719. If the signal frequency applied to a rectangular guide is increased and the dominant mode is employed 12720. the free space wavelength is increased 12721. the phase velocity increased 12722. the guide wavelength is increased 12723. the group velocity, Vg, is increased 12724. If a 6 GHz signal is applied to a rectangular waveguide and the reflection angle is 20o, what is the value of the guide wavelength? 12725. 6.10 cm 12726. 5.32 cm 12727. 4.78 cm 12728. 5.00 cm 12729. The inner dimensions of a rectangular wavelength are 1.75 cm by 3.5 cm. The cutoff wavelength for the dominant mode is 12730. 1.75 cm 12731. 3.5 cm 12732. 7.0 cm 12733. 0.4375 cm 12734. A signal whose wavelength is 3.5 cm is being propagated along a guide whose inner dimensions are 2 cm by 4 cm. What is the value of the guide wavelength? 12735. 3.12 cm 12736. 3.89 cm 12737. 3.57 cm 12738. 6.30 cm 12739. The frequency range over which a rectangular waveguide is excited in the dominant mode is limited to 12740. the difference between the frequency for which the reflection angle is 90o and the frequency for which angle is zero 12741. the difference between the frequency for which the free-space wavelength is equal to the cutoff value and the frequency for which the free-space wavelength is equal to the guide wavelength 12742. the difference between the frequency at which the cutoff wavelength is twice the narrow dimension 12743. none of these 12744. If a rectangular waveguide is to be excited in the dominant mode, the E-probe should be inserted 12745. at the sealed end 12746. at a distance of one quarter –wavelength from the sealed end 12747. at a distance of one-half wavelength from the sealed end 12748. at a distance of three-quarters of a wavelength from the sealed end 12749. A quarter-wave line is connected to an RF generator and is shorted out at the far end. What is the input impedance to the line generator? 12750. A low value of resistance 12751. A high value of resistance 12752. A capacitive resistance which is equal in the value to the line’s surge impedance 12753. An inductive resistance which is equal to the value to the line’s surge impedance 12754. If the SWR on a transmission line has a high value, the reason could be 12755. an impedance mismatch between the line and the load 12756. that the line is non-resonant 12757. a reflection coefficient of zero at the load 12758. that the load is matched to the line 12759. If a quarter-wave transmission line is shorted at one end 12760. there is minimum current at the shorted end 12761. the line behaves as a parallel-tuned circuit in relation to the generator 12762. the line behaves as a series-tuned circuit in relation to the generator 12763. there is a minimum voltage at the shorted end 12764. A 50-ohm transmission line is feeding an antenna which represents a 50 ohm resistive load. To shorten the line, the length must be 12765. any convenient value 12766. an odd multiple of three quarters of a wavelength 12767. an odd multiple of half a wavelength 12768. an even multiple of a quarter of a wavelength 12769. The outer conductor of the coaxial cable is usually grounded 12770. at the beginning and at the end of the cable 12771. only at the beginning of the cable and only at the end of the cable 12772. only at the end of the cable 12773. at the middle of the cable 12774. A feature of an infinite transmission line is that 12775. its input impedance at the generator is equal to the line’s surge impedance 12776. its phase velocity is greater than the velocity of light 12777. no RF current will be drawn from the generator 12778. the impedance varies at different positions on the line 12779. When the surge impedance of a line is matched to a load, the line will 12780. transfer maximum current to the load 12781. transfer maximum voltage to the load 12782. transfer maximum power to the load 12783. have a VSWR equal to zero 12784. A lossless line is terminated by a resistive load which is not equal to the surge impedance. If the value of the reflection coefficient is 0.5, the VSWR is 12785. 2 12786. 3 12787. 4 12788. 15 12789. Ratio of the mismatch between the antenna and the transmitter power. 12790. Standing wave pattern 12791. Reflection coefficient 12792. SWR 12793. Index of refraction 12794. Emission designation for a facsimile. 12795. H3E and A4E 12796. R3E and A4E 12797. F4E and J3E 12798. F3C and A3E 12799. Commonly used telephone wire. 12800. AWG #19 12801. AWG #18 12802. AWG #30 12803. AWG #33 12804. What is the distance traveled by a wave in the time of one cycle? 12805. Frequency 12806. Hop 12807. Wavelength 12808. Crest 12809. The velocity factor is inversely proportional with respect to the ______. 12810. square of the dielectric constant 12811. square root of the dielectric constant 12812. dielectric current 12813. square root of refractive index 12814. ______is a hollow structure that has no center conductor but allows waves to propagate down its length. 12815. Waveguide 12816. Hybrid 12817. Pipe 12818. Directional coupler 12819. To connect a coaxial line to a parallel wire line, ______is used. 12820. hybrid circuit 12821. balun 12822. directional coupler 12823. quarter-wave transformer matching circuit 12824. What length for which the input power has been halved for a transmission line with an attenuation of 6 dB/km? 12825. 1.5 km 12826. 0.5 km 12827. 63 km 12828. 2 km 12829. Ina waveguide, ______is a specific configuration of electric and magnetic fields that allows a wave to propagate. 12830. set-up 12831. coupler 12832. channel 12833. mode 12834. A rectangular waveguide has dimensions of 3 cm x 5 cm. What is the dominant mode cut-off frequency? 12835. 2 GHz 12836. 3 GHz 12837. 2.5 GHz 12838. 3.5 GHZ 12839. ______are transmission lines which can convey electromagnetic waves only in higher order modes? 12840. Coaxial cables 12841. Twisted pairs of telephone wire 12842. Power cables 12843. Waveguides 12844. The amount of uncertainty in a system of symbols is also called 12845. bandwidth 12846. loss 12847. entropy 12848. quantum 12849. The twists in twisted wire pairs 12850. reduced electromagnetic interference 12851. occur at a 30-degree angle 12852. eliminate loading 12853. were removed due to cost 12854. An example of a bounded medium is 12855. coaxial cable 12856. waveguide 12857. fiber-optic cable 12858. all of the above 12859. Loading means the addition of 12860. resistor 12861. capacitor 12862. bullet 12863. inductance 12864. What is the most commonly used transmission line for high frequency application? 12865. Two-wire balance line 12866. Single wire 12867. Three-wire line 12868. Coaxial 12869. The characteristic impedance of a transmission line does not depend upon its 12870. length 12871. conductor diameter 12872. conductor spacing 12873. dielectric material 12874. One of the following is not a common transmission line impedance. 12875. 50 ohms 12876. 75 ohms 12877. 120 ohms 12878. 300 ohms 12879. For maximum absorption of power at the antenna, the relationship between the characteristic impedance of the line Zoand the load impedance ZL should be 12880. Zo = ZL 12881. Zo > ZL 12882. Zo < ZL 12883. Zo = 0 12884. The mismatch between antenna and transmission line impedance cannot be corrected for by 12885. using LC matcging network 12886. adjusting antenna length 12887. using a balun 12888. adjusting the length of transmission line 12889. ______is a pattern of voltage and current variations along a transmission line not terminated in its characteristic impedance. 12890. An electric field 12891. Radio waves 12892. Standing waves 12893. A magnetic field 12894. Which is the desirable SWR on a transmission line? 12895. 0 12896. 1 12897. 2 12898. Infinity 12899. A 50ohm coax is connected to a 73-ohm antenna. What is the SWR? 12900. 0.685 12901. 1 12902. 1.46 12903. 2.92 12904. What is the most desirable reflection coefficient? 12905. 0 12906. 0.5 12907. 1 12908. Infinity 12909. What is the ratio expressing the percentage of incident voltage reflected on a transmission line? 12910. Velocity factor 12911. Standing-wave ratio 12912. Reflection coefficient 12913. Line efficiency 12914. The minimum voltage along a transmission line is 260 V, while the maximum is 390 V, the SWR is 12915. 0.67 12916. 1.0 12917. 1.2 12918. 1.5 12919. One meter is one wavelength at a frequency of 12920. 150 MHz 12921. 164 MHz 12922. 300 MHz 12923. 328 MHz 12924. At very high frequencies, transmission lines act as 12925. Tuned circuits 12926. Antennas 12927. Insulators 12928. Resistors 12929. A shorted quarter-wave line at the operating frequency acts like a/an 12930. Capacitor 12931. Inductor 12932. Series resonant circuit 12933. Parallel resonant circuit 12934. A shorted half-wave line at the operating frequency acts like a/an 12935. Capacitor 12936. Inductor 12937. Series resonant circuit 12938. Parallel resonant circuit 12939. A medium least susceptible to noise? 12940. Shielded pair 12941. Twisted pair 12942. Fiber-optic 12943. Coaxial 12944. A medium most widely used in LANs? 12945. Parallel-wire line 12946. Twisted pair 12947. Fiber-optic cable 12948. Coaxial 12949. The most commonly used transmission line in television system. 12950. Parallel-wire line 12951. Coaxial cable 12952. Waveguide 12953. Open-wire ceramic supports 12954. The impedance of a TV transmission line depends on several factors. Which is not one of those factors? 12955. Diameter 12956. Length of the wire 12957. Dielectric material 12958. Separation between conductors 12959. DC blocks are used in coaxial transmission line for the purpose of 12960. passing DC while blocking AC 12961. passing AC voltage but prevent DC 12962. preventing AC voltage from reaching the pre-amplifier 12963. preventing AC power supply voltage from being shorted by a balun or band splitter 12964. ______is a type of interference caused by off-air TV channels 2 and 4, plus a satellite dish operating on channel 3. 12965. Adjacent channel interference 12966. Ghost 12967. Co-channel interference 12968. Crosstalk 12969. Dithering (in TVRO communication) is a process of Reducing the effect of noise on the TVRO video signal Centering the video fine tuning on TVRO channels Moving the feedhorn rotor to the precise angle Moving the actuator exactly onto the desired satellite beam 12970. A network that has an input of 75dB and an output of 35dB. The loss of the network is -40db 40db 40dBm -4dBm 12971. Important useful quantities describing waveforms. Time and frequency Voltage and current Frequency and voltage Power and frequency 12972. Halving the power means 6-dB gain 3-dB loss 3-dB gain 6-dB loss 12973. One Neper (Np) is how many decibels? 8.866 8.686 8.688 8.868 12974. A signal is amplified 100 times in power. The dB gain is 20dB 119dB 15dB 25dB 12975. Which of the following is used to measure SWR? Spectrum analyzer Reflectometer Oscilloscope Multimeter 12976. 214-056 twin lead which is commonly used for TV lead-in has a characteristic impedance of 52 ohms 75 ohms 600 ohms 300 ohms 12977. What is the characteristic impedance of a transmission line which is to act a s a quarterwave matching transformer between a 175 ohms transmission line and 600 ohms load? 300.04 ohms 324.04 ohms 310.04 ohms 320.04 ohms 12978. What is the EIRP in dBW of a 50dB antenna connected to a transmitter with an output of 10kW through a transmission line with loss of 5dB? 85dBW 955 dBW 90 dBW 80 dBW 12979. A coaxial cable is a good example of a/an Unbounded medium Transmission channel Non-metallic medium Bounded medium 12980. If a quarterwave transformer is required to match a 180 ohm load to a transmission line with and impedance of 300 ohms, what should be the characteristic impedance of the matching ransformer? Assume that the matching transformer is to be connected directly to the load. 180 ohms 232 ohms 300 ohms 480 ohms 12981. A transmitter of 100W RF power output, 100% modulated is operating on a frequency of 169MHz. The antenna transmission line consists of a 50 ohms coaxial cable 150ft long. The coaxial inner conductor outer diameter is 0.162in. determine the outside diameter of the outer conductor if the outer conductor has a thickness of 0.05 in(assume K=1). 1.0 in 0.9in 0.7in 0.5in 12982. In the preceding problem , calculate the line current. 1.7A 1.3A 1.5A 1.0A 12983. Determine also the total attenuation of the line in the preceding problem. 2.0dB 1.5 dB 2.5 dB 1.0 dB 12984. What is the maximum subscriber loop length, in ft, of a telephone system if the signalling resistance is 1800ohms using a telephone cable pair of gauge #26 with loop resistance of 83.5 ohms per 100ft. Assume the telephone set resistance is equal to 200 ohms. 15,161.7 feet 19,161 feet 15,300 feet 20,000 feet 12985. If the same subscriber loop above limits the voice attenuation to a maximum of 6dB, what is the maximum allowable subscriber loop length, in feet, using the same gauge #26 telephone wire? Assume a 2.7dB loss per mile. 20,000 ft 13,900 ft 15,280ft 11,733ft 12986. The input is 0.1W and the network gain is 13dB, the output is 2.0W 2.5W 1.5W 1.8W 12987. Known as one-tenth of a neper. dB dBm dBp dNp 12988. the input impedance of a quarterwave short-circuited transmission line at its resinant frequency is 0 ohms Infinite or an open circuit Ohm 70 ohms 12989. The ratio of the largest rms value to the smallest rms value of the voltage in the line is called SWR ISWR VSWR Coefficient of reflection 12990. An open-wire, two-wire transmission line is to be connected to a dipole antenna through a quarter-wave matching stub. At a frequency of 10 MHz, compute the length of the dipole 20 meters 7.5 meters 15 meters 25 meters 12991. From the preceding problem, compute also the length of the quarterwave stub. 15 meters 7.5 meters 20 meters 25 meters 12992. To find the characteristic impedance of a coaxial cable, measurements are made with (a) the far end open circuited and (b) far end short circuited, the corresponding readings being a) Ro=3ohms and Xc=55 ohms, capacitive b) RS = 10 ohms and XL = 90 ohms, inductive. What is the characteristic impedance Zo of the line? 75.7-j2.0 ohms 70.7+j1.19 ohms 87.5 – j5 ohms 70.7 – j1.97 ohms 12993. A TV antenna receives a signal measured at 200mV and is immediately amplified by a preamplifier with a 15dB gain. This amplified signal then passes through a coaxial cable with 3dB loss, what is the resulting input to the TV set, in dBmV? 1.98 13.98 -1.98 -13.98 12994. The characteristic impedance of a transmission line does not depend upon its______. Conductor spacing Conductor diameter Length Conductor radius 12995. What does a power difference of -3dB mean? A loss of one third of the power A loss of one half of the power A loss of three watts of power No significant change 12996. Which of the following is an advantage of the balance transmission line? Easy installation Outer shield eliminates radiation losses Low attenuation None of these 12997. Waveguides are used mainly for microwave transmission because They are bulky at lower frequencies Losses are heavy at lower frequencies They depend on straight line propagation No generators are powerful enough to excite them 12998. The input is 1W and the network loss is 27dB, the output is 1mW 3mW 2mW 4mW 12999. A combiner has two inputs +30dBm and +30dBm, what is the resultant output? +36 dBm +30 dBm +60 dBm +33 dBm 13000. The ratio of the smallest to the largest rms current value is called SWR VSWR ISWR Coefficient of reflection 13001. If the ratio of the maximum current to minimum current in a transmission line is 2:1 then the ratio of the maximum voltage to minimum voltage is 4:1 1:2 1:4 2:1 13002. Two wires of 600 ohms characteristic impedance is to be constructed out of a number 12 wire (81 mils). Find the attenuation of the line at 0.6GHz per 100feet length 0.05 dB 0.55 dB 0.44 dB 0.35 dB 13003. In the preceding problem, determine the spacing between wires from center to center. 6 in 4 in 5 in 3 in 13004. A lossless transmission line has a shunt capacitance of 100nF/m and a series inductance of 4mH/m. What is the characteristic impedance? 500 ohms 400ohms 300ohms 200hms 13005. A ten times power change in transmission system is equivalent to 10dBm 1dB 20dB 100dB 13006. A type of transmission line employed where balanced properties are required. Balun Parallel-wire line Coaxial line Quarterwave line 13007. What is the characteristic impedance of a transmission line which has a capacitance of 40nF/ft and an inductance of 0.5mH/ft 111.8 ohms 110.8 ohms 112.8 ohms 109.8 ohms 13008. The input power to a loss-free cable is 5W. If the reflected power is 7dB down on the incident power, the output power to the load is 4W 5W 6W 7W 13009. To be properly matched the ratio of a maximum voltage along a transmission line should be equal to 1 10 50 2 13010. A coaxial line with an outer diameter of 6mm has a 50 ohms characteristic impedance. If the dielectric constant of the insulation is 1.60., calculate the inner diameter. 2.09cm 2.09in 2.09mm 2.09mm 13011. If an amplifier has equal input and out impedance, what voltage ratio does the gain of 50dB represent? 316.2 325.2 320.1 315.0 13012. What is the inductance per foot of a cable that has a capacitance of 50 pF/ft and a characteristic impedance of 60 ohms? 0.167uH/ft 0.178 uH/ft 0.19 uH/ft 0.18 uH/ft 13013. The ratio between the energy absorbed by a surface to the total energy received by the surface. Reflection coefficient Absorption coefficient Linear coefficient Thermal coefficient 13014. When the diameter of the conductors of a wire transmission line is held constant, the effect of decreasing the distance between the conductors is Increase the surge impedance Increase the radiation resistance Decrease the SWR Decrease the impedance 13015. The higher the gauge number if a conductor The bigger the diameter The higher the resistance or the smaller the diameter The higher the resistance None of the above 13016. A short length transmission line used to reduce/eliminate standing waves in the main transmission line. Stub Balun λ/4 transformer slot 13017. ratio of reflected power to incident power? Incidence Reflectance Reflection index None of these 13018. A quarter wave transformer is used to match a 600 ohms lad antenna to a ling of 52 ohms impedance, the characteristic impedance of the matching transformer is 200 ohms 150 ohms 176 ohms 300 ohms 13019. What is the capacitance of 55 miles #44 copper wire spaced 18 inches? From wire tables, #44 wire has a radius to 0.10215 in. 0.476uF 0.476nF 0.476pF 0.476fF 13020. A two-transmission line consists of No. 12 wire AWG (81mils). The distance between wire centers is 10 inches. What is the characteristic impedance of the line? 650 ohms 300 ohms 600 ohms 660 ohms 13021. In the preceding problem, what is the attenuation in dB per 100ft of the line for a frequency of 4 MHz? 0.05 0.03 0.04 0.06 13022. What is the SWR when a transmission line is terminated in a short circuit? Zero One Infinite indeterminate 13023. 13024. 13025. 13026. 13027. 13028. 13029. 13030. 13031. Typical speech power 13032. 10 to 1000 µW 13033. 100 to 1000 mW 13034. 10 to 1000 nW 13035. 100 to 1000 pW 13036. The maximum intelligibility for voice frequency is located between 13037. 250 and 500 Hz 13038. 1000 and 3000 Hz 13039. 500 and 1000 Hz 13040. 3000 and 5000 Hz 13041. The maximum voice energy is located between 13042. 250 and 500 Hz 13043. 1000 and 3000 Hz 13044. 500 and 1000 Hz 13045. 3000 and 5000 Hz 13046. A device used to measure speech volume. 13047. speech meter 13048. volume meter 13049. volume unit meter 13050. speedometer 13051. By definition, for a sine wave 13052. 0 dBm = 0 V.U. 13053. 0 dBW = 0 V.U. 13054. 0 dBa = 0 V.U. 13055. 0 dBf = 0 V.U. 13056. Presently, this is the “standard” frequency bandwidth for voice transmission. 13057. 0 to 4000 Hz 13058. 100 to 3400 Hz 13059. 300 to 3400 Hz 13060. 300 to 3000 Hz 13061. Which of the following is commonly used wire for subscriber loop design? 13062. AWG # 19 13063. AWG # 18 13064. AWG # 30 13065. AWG # 33 13066. The resistance limit for No. 2 Crossbar Exchange (US) is 13067. 1300 Ω 13068. 2000 Ω 13069. 1250 Ω 13070. 1200 Ω 13071. AWG # 26 has a typical loss of 13072. 0.21 dB/1000 ft. 13073. 0.32 dB/1000 ft. 13074. 0.41 dB/1000 ft. 13075. 0.51 dB/1000 ft. 13076. What is the standard voice channel spacing? 13077. 44 MHz 13078. 40 kHz 13079. 4 kHz 13080. 40 MHz 13081. Which tester is used to measure SWR? 13082. Multimeter 13083. Oscilloscope 13084. Spectrum analyzer 13085. Reflectometer 13086. What is singing? 13087. The result of intermodulating two or more signals of different frequencies to produce a tone having a frequency equal to the sum of the frequencies of the signals intermodulated. 13088. The result of intermodulating two or more signals of different frequencies to produce a tone having a frequency higher than that of the signal having the highest frequency. 13089. An undesired self-sustained oscillation in a system, generally caused by excessive positive feedback. 13090. An art or form of entertainment that can make one rich. 13091. Which stage increases the selectivity of the circuit in an AM receiver? 13092. Detector 13093. IF stage 13094. Modulator 13095. Mixer 13096. The ______of radio receiver amplify weak signal and produce a desirable intelligence at the output speaker. 13097. sensitivity 13098. selectivity 13099. reliability 13100. fidelity 13101. Full-duplex transmission means 13102. One-way transmission 13103. 24-hour transmission 13104. Broadcast transmission 13105. Two-way simultaneous transmission 13106. What is a multidrop line? 13107. A piece of wire with a thick insulating material that serves to protect the conductive materials from damage in the event the wire is dropped. 13108. A line designed to withstand high pressure. 13109. A line or circuit interconnecting several situations. 13110. A bus line 13111. A passive ______is an electronic device which reduces signal strength by a specified amount in dB. 13112. Splitter 13113. Filter 13114. Trimmer 13115. Attenuator 13116. The signal quality of the calls is constantly monitored by the base station, when the quality of the calls drops below a certain specified level. The base request the MTSO to try and find a better cell site. 13117. Hand-off 13118. Cell splitting 13119. Roaming 13120. Frequency reuse 13121. A digital identification associated with a cellular system. 13122. SAT 13123. SID 13124. ESN 13125. MIN 13126. How many seconds does facsimile transmit a stranded page? 13127. 5 13128. 10 13129. 20 13130. 25 13131. A kind of recording used in facsimile. 13132. Electrolytic recording 13133. Electrothermal recording 13134. Electropercussive recording 13135. Electrostatic recording 13136. A type of distortion a facsimile produce when it becomes out of synchronization? 13137. Pincushion 13138. Barrel 13139. Skewing 13140. Fattening 13141. What is an acoustic coupler? 13142. A device that radiates audible signals via a transmitting antenna 13143. A device that converts electric signals into audio signals, enabling data to be transmitted over the public telephone network via a conventional telephone handset 13144. A device that receives audible signals and retransmits them at VHF frequencies 13145. A transducer 13146. Cause a herringbone pattern in facsimile 13147. Single-frequency interference 13148. Crosstalk 13149. Phase jitter 13150. Noise 13151. The ______in an FM receiver causes a stronger signal to dominate over a weaker signal on the same frequency. 13152. Capture effect 13153. Flywheel effect 13154. Hall effect 13155. Skin effect 13156. A device that converts a 2-wire circuit to a 4-wire circuit. 13157. RS-232 interface 13158. Hybrid circuit 13159. Balun 13160. Stub 13161. ______theory is deciding between a set of hypothesis when given a collection of imperfect measurements. 13162. Estimation 13163. Traffic 13164. Decision 13165. Nyquist 13166. ______of a data reduction says that when reducing a set of data into the form of an underlying mode, one should be maximally non-committal with respect to missing data. 13167. Jaynes maximum entropy principle 13168. Kullback principle of minimum discrimination 13169. Minimum discrimination\ 13170. Maximum entropy 13171. ______is selecting the best value of a parameter from a continuum of possible values when gives a collection if imperfect measurements 13172. Estimation 13173. Traffic 13174. Decision 13175. Nyquist 13176. Combination of madulator, channel, and detector. 13177. Transceiver 13178. Transponder 13179. T/R channel 13180. Discrete channel 13181. What is the frequency band of DECT? 13182. 1.88 – 1.90 GHz 13183. 1.68 – 1.70 GHz 13184. 1.48 – 1.50 GHz 13185. 1.28 – 1.30 GHz 13186. How many simultaneous calls does each DECT system can support? 13187. 96 13188. 12 13189. 24 13190. 49 13191. How many simultaneous calls does a DECT radio transceiver can assess at any given time? 13192. 120 13193. 240 13194. 480 13195. 960 13196. The AGC voltage of a radio receiver is always ______. 13197. Present before adjustments can be made 13198. DC, but may have either polarity positive DC 13199. Positive DC 13200. Negative 13201. What is a concentrator? 13202. A system that improves the signal-to-noise ratio by compressing the volume range of a signal. 13203. A device that varies the characteristics of a carrier signal in accordance with the waveform of a modulating signal which contains useful information 13204. A switching system that lets a large number of telephone or data processing subscribers use a lesser number of transmission lines or a narrow bandwidth 13205. Equipment in the central office. 13206. If you find that an SAW filter output is 6 dB down from the input of a receiver during test, ______13207. This is normal. 13208. The device if faulty 13209. The receiver is improperly terminated 13210. The filter is not resonating 13211. A triple conversion superheterodyne receiver, diode mixer stages are 13212. Operated in the linear region 13213. Operated in the nonlinear region 13214. Operated as Class-A amplifiers 13215. Operated as Class-B amplifiers 13216. What is a leased line? 13217. A piece of wire used in a local area network in one building 13218. A piece of wire connecting a telephone set to a PABX 13219. A temporary connection of one computer to a mainframe via a modern and a telephone line 13220. A permanent circuit for a private use within a communication network 13221. If two FM signals of different strengths are received on the same frequency 13222. One steady heterodyne will appear in the AM output 13223. Both will appear in the AF output 13224. Only the stronger will appear in the AF output 13225. Neither signal will be intelligence unless the weaker signal is at least 10 times 13226. Cellular mobile system was first operated in 13227. 1979 13228. 1981 13229. 1983 13230. 1985 13231. TACS is a cellular system with ______channels. 13232. 666 13233. 1000 13234. 832 13235. 200 13236. Supervisory Audio Tone (SAT) has ______frequency. 13237. 5960 Hz 13238. 6000 Hz 13239. 6040 Hz 13240. 1004 z 13241. What is the number of channels of a cellular system with an allocated spectrum of 25 MHz and with a channel of 30 kHz bandwidth? 13242. 833 13243. 240 13244. 1000 13245. 666 13246. GSSM uses what digital modulation technique? 13247. QAM 13248. GFSK 13249. BPSK 13250. GMSK 13251. What is the power output of Personal Communication System (PCS)? 13252. 10 mW 13253. 75 mW 13254. 150 mW 13255. 10 W 13256. RG-B8 cable has a loss of about ______dB at cellular frequencies up to 15 ft. length. 13257. 2 13258. 1 13259. 4 13260. 3 13261. The signals designed to keep the receivers and transmitters aligned. 13262. Carrier frequencies 13263. Pilot carrier signals 13264. Synchronizing signals 13265. Reference signals 13266. If the spacing of a two-wire open air transmission line is 12 inches and the conductor diameter is 0.25 inch, the characteristic impedance is 13267. 547 Ω 13268. 357 Ω 13269. 273 Ω 13270. 300 Ω 13271. The impedance of the quarterwave transformer used to match a 600 Ω line to a 300 Ω load is 13272. 382 Ω 13273. 424 Ω 13274. 565 Ω 13275. 712 Ω 13276. When a line and a load are match the reflection coefficient is 13277. Unity 13278. Zero 13279. Positive infinity 13280. Negative infinity 13281. When line is terminated in an open circuit load, the reflection coefficient is 13282. A. Unity 13283. B. Zero 13284. C. Positive infinity 13285. D. Negative infinity 13286. A 300 ohms line is terminated in a resistance load of 200 ohms, the VSWR is 13287. 0.65 13288. 1.5 13289. Unity 13290. Zero 13291. If the reflection coefficient is 0.5, the standing wave ratio is 13292. 0.33 13293. Unity 13294. 3 13295. Zero 13296. To least the fault of the given line, a signal is fed to the line, 30 µs later the signal returned. What is the distance of the fault? 13297. 9000 m 13298. 300 m 13299. 100 m 13300. 4500 m 13301. The telephone set is powered by the central office on the ring side at 13302. 42 to 52 Vdc 13303. – 42 to -52 Vdc 13304. 24 to 64 Vdc 13305. – 24 to – 64 Vdc 13306. The telephone voice band frequency is from 13307. 300 to 4 kHz 13308. 400 to 3400 Hz 13309. 300 to 3400 Hz 13310. 400 to 4 kHz 13311. Which of the following wire is used to transmit the signal? 13312. Black 13313. Yellow 13314. Red 13315. Green 13316. The corresponding frequency for digit 7 in the touch tone telephone is 13317. 770 & 1477 Hz 13318. 852 & 1209 Hz 13319. 852 & 1336 Hz 13320. 770 & 1336 Hz 13321. The physical connection between the telephone set and the switching equipment is called the 13322. Trunk line 13323. Link 13324. Subscriber loop 13325. Leased line 13326. What is the local loop of a telephone system? 13327. It is a two-wire or four-wire communication circuit between the customer’s premise and the central office 13328. It is a group of wires connecting a telephone set to a modern 13329. It is a four-wire circuit connecting a facsimile machine to a computer 13330. It is a single piece of wire connecting the subscriber’s telephone set to another set in an adjacent room. 13331. Which of the ff. equipment is used in long loop design? 13332. Dial long lines 13333. Voice repeater 13334. Loop range extender 13335. All of the above 13336. What is a two-wire circuit? 13337. A circuit usually in the subscriber loop, between the telephone set and the local central office. 13338. A circuit having only two terminals, both terminals having the same instantaneous voltage. 13339. A circuit with one input terminal, one output terminal, and a common ground. 13340. A circuit consisting of two transmission lines. 13341. 1 mW is equal to 13342. 90 dBm 13343. 0 dBm 13344. -30 dBm 13345. 120 dBm 13346. Which of the following responds to the request of a subscriber by sending a dial tone? 13347. Line finder 13348. First selector 13349. Connector 13350. Line equipment 13351. The other name of Class 2 office in the North American Switching Plan. 13352. Primary center 13353. Section 13354. Regional center 13355. Toll points 13356. A cell in the cellular telephone system means 13357. A power source 13358. Small area 13359. Large area 13360. Service area 13361. What is the linking point between cell phone and regular telephone? 13362. Base station 13363. Control office 13364. C.O. 13365. MTSO 13366. What is the typical power output of a cellular phone? 13367. 5 W 13368. 10 W 13369. 1 W 13370. 3 W 13371. When a single cell is divided into smaller cells that process is called 13372. Cell splitting 13373. Cell division 13374. Reuse 13375. Cell sharing 13376. The first cell shape is a square 13377. Square 13378. Circle 13379. Rectangle 13380. Triangle 13381. In order to provide 100% coverage without overlap, cellular telephone system can use 13382. Hexagon cell shape 13383. Triangle 13384. Rectangular 13385. All of the above 13386. What is the beamwidth of the reflector of the receiving antenna in the base station 13387. 20 degrees 13388. 30 degrees 13389. 50 degrees 13390. 60 degrees 13391. A cellular phone operates on 13392. Half duplex 13393. Full duplex 13394. Echoplex 13395. Lincomplex 13396. Cellular phones transmit in the band from 13397. 825 to 845 MHz 13398. 835 to 855 MHz 13399. 825 to 855 MHz 13400. 825 to 865 MHz 13401. Cell phone receives in the band from 13402. 860 to 880 MHz 13403. 870 to 890 MHz 13404. 870 to 880 MHz 13405. 860 to 890 MHz 13406. What is the frequency separation between the transmit and the receive channels? 13407. 30 MHz 13408. 45 MHz 13409. 55 MHz 13410. 40 MHz 13411. For channel 1, transmit/receive frequency is 13412. 825.030/870.030 MHz 13413. 835.03/880.03 MHz 13414. 825.015/870.015 MHz 13415. 825.15/870.15 MHz 13416. The number of transmit/receive channels in the cellular system is 13417. 625 13418. 645 13419. 655 13420. 666 13421. The transmission range of cellular telephony is generally about 13422. 80 km 13423. 65 km 13424. 160 km 13425. 16 km 13426. One of the following is not an advantage of a cellular telephone system 13427. Privacy 13428. Large service area 13429. No interference 13430. Mobility 13431. When the message is transferred from one cell site transmitter to another cell site transmitter as the caller crosses a boundary ______process takes place. 13432. Shifting 13433. Hand off 13434. Give off 13435. Turn over 13436. What is the sensitivity of a cellular receiver? 13437. 20 dB 13438. 40 dB 13439. 50 dB 13440. 60 dB 13441. What is the frequency deviation of the cellular telephone system? 13442. ±15 kHz 13443. ±30 kHz 13444. ±12 kHz 13445. ±75 kHz 13446. Hailing channel is otherwise known as 13447. Conversation channel 13448. Calling channel 13449. Signaling channel 13450. Remote channel 13451. What is an Erlang? 13452. It is a unit of magnetic field intensity measured around a conductor 13453. It is the number of erroneous bits received per unit of time 13454. It a unit of electrical energy radiated in space. 13455. It is equal to the number of simultaneous calls originated during a specific hourly period. 13456. All of the cell base stations are linked together by ______which serves as the central office and management node for the group. 13457. MTS 13458. IMTS 13459. MSTO 13460. MTSO 13461. Provides interface between the mobile telephone switching office and the mobile units. 13462. Database 13463. Cell site 13464. Terrestrial link 13465. Radio transmitter 13466. A phone call over the cellular network actually requires 13467. Simplex channels 13468. Half duplex channels 13469. Full duplex channels 13470. Full/full duplex 13471. A method of expressing the amplitudes of complex non-periodic signals such as speech. 13472. Volume 13473. Pitch 13474. Frequency 13475. Wavelength 13476. ______is signal returned to the talker after one or more round trips between the talker and the listener. 13477. Singing 13478. Echo 13479. Jitter 13480. Crosstalk 13481. ______is a voice operated device that inserts a high loss in the opposite direction of transmission of the talking party. 13482. Hybrid 13483. 2-wire circuit 13484. Echo suppressor 13485. VNL 13486. _____ is picking up of the same station at two nearby points on the receiver dial. 13487. Double spotting 13488. Hot shot 13489. Image frequency 13490. Bail shot 13491. When one channel picks up the signal carried by another channel. 13492. Echo 13493. Crosstalk 13494. Party line 13495. Crosslink 13496. What type of connector arrangement wherein a customer may move to another location and still retain the same telephone number. 13497. TPL 13498. Bridge 13499. TPS 13500. Party line 13501. It is an advantage of sidetone. 13502. Transmission efficiency is increased 13503. Speaker increase his voice resulting in a strengthened signal 13504. No dissipation of energy in the balancing network 13505. Assures the customer that the telephone is working 13506. Radio communications between points using a single share frequency. 13507. Simplex 13508. Full duplex 13509. Half-duplex 13510. Full/full duplex 13511. The transmission of information from multiple sources occurring on the same facility but not as the same time. 13512. FDM 13513. TDM 13514. WDM 13515. CDM 13516. When human voice and music are transmitted, the type of communication employed is known as 13517. Raditechnology 13518. Audio frequency 13519. Wired audio 13520. Radiotelephony 13521. Printed documents to be transmitted by fax are converted into baseband electric signal by the process of 13522. Copying 13523. Scanning 13524. Modulation 13525. Light variation 13526. What is the most commonly used light sensor in a modern fax machine? 13527. Phototube 13528. Phototransistor 13529. Liquid-crystal display 13530. Charge couple device 13531. In FM fax, the frequencies for black and white are ______repectively. 13532. 1500 and 2300 Hz 13533. 2300 and 1500 Hz 13534. 1300 and 2400 Hz 13535. 1070 and 1270 Hz 13536. Which resolution produces the best quality fax? 13537. 96 lines per inch 13538. 150 lines per inch 13539. 200 lines per inch 13540. 400 lines per inch 13541. Group 2 fax uses which modulation? 13542. SSB 13543. FSK 13544. Vestigial sideband AM 13545. PSK 13546. The most widely used fax standard is 13547. Group 1 13548. Group 2 13549. Group 3 13550. Group 4 13551. Group 3 fax uses which modulation? 13552. QAM 13553. ASK 13554. PSK 13555. GFSK 13556. Block calls held condition specified the held probability at a time period equal to an average holding time. 13557. Erlang B 13558. Erlang C 13559. Erlang D 13560. Poisson 13561. What is an Echo? 13562. A signal of the same amplitude but 180 degrees out of phase from the original signal and mixed with the original signal at the transmitter to produce a more intelligible output signal 13563. A wave which has been reflected or otherwise returned with the sufficient magnitude and delay for it to be perceptible in some manner as a wave distinct from that directly transmitted. 13564. The signal having a higher frequency than the original and transmitted back to earth by a passive satellite. 13565. A reflected signal. 13566. What is the system used by Personal Communication Network (PCN)? 13567. TACS 13568. Modified GSM 13569. AMPS 13570. CDMA 13571. Termination refers to 13572. Cutting both ends of a conductor 13573. Disconnecting a line from a transmitter 13574. Looking back impedance of a line with no load 13575. Load connected to the output end of a transmission line 13576. The multiple access used by Digital European Cordless Telephone (DECT) 13577. CDMA 13578. FDMA 13579. TDMA 13580. CDMA/FDMA 13581. Blocked calls delay condition specified delay probability 13582. Erlang B 13583. Erlang C 13584. Erlang D 13585. Poisson 13586. Status information provided by telephone signaling. 13587. Busy tone, dial tone and ringing 13588. Congestion and call charge data 13589. All of the above 13590. None of the above 13591. The modulation technique used by DECT. 13592. GFSK 13593. ASK 13594. QAM 13595. PSK 13596. What is a four-wire circuit? 13597. Is used between serving central offices for long-distance connections, with one pair being used for each direction of transmission. 13598. Is a circuit with three output terminals and one input terminal 13599. Is an oscillator that produces four different frequencies simultaneously 13600. A circuit consisting of four transmission lines. 13601. Cellular CDMA system uses what modulation method? 13602. GFSK 13603. ASK 13604. QAM 13605. BPSK 13606. PABX means 13607. Private All-purpose Broadcasting Exchange 13608. Private Automatic Branch Exchange 13609. Public Access Bi-directional Exchange 13610. Public Automatic Branch Exchange 13611. What is the voted cellular digital standard at TIA? 13612. Digital AMPS 13613. GSM 13614. CDMA 13615. TACS 13616. What is the number of channels for Band A and for Band B in Digital AMPS 13617. 832 13618. 416 13619. 666 13620. 888 13621. The mobile-to-base frequency assignment for GSM system is 13622. 890-915 MHz 13623. 935-960 MHz 13624. 870-890 MHz 13625. 825-845 MHz 13626. The range (in miles) of a cellular CDMA system. 13627. 13 13628. 30 13629. 45 13630. 20 13631. In a cellular system, ______is used to measure the spectrum efficiency. 13632. Radio efficiency 13633. Diversity 13634. Frequency reuse 13635. Radio capacity 13636. Which of the following echo is completely out of control? 13637. Worst echo 13638. Reverberation 13639. Singing 13640. Feedback 13641. Which of the following devices increase the battery voltage on a loop and extends its signaling range? 13642. Loop extender 13643. VF repeater 13644. VF amplifier 13645. All of these 13646. Under ordinary circumstances, the CCITT recommends that the number of circuits in tandem must not exceed 13647. 9 13648. 10 13649. 11 13650. 12 13651. What is the system capacity of AMPS? 13652. 30,000 13653. 60,000 13654. 100,000 13655. 120,000 13656. NAM means 13657. Non Alternable Memory 13658. Numeric Allocation Module 13659. Numeric Assignment Module 13660. Numeric Access Module 13661. Modulation – Chapter 3 13662. ______is the maximum sideband suppression value using filter system. 13663. 50 dB 13664. 60 dB 13665. 40 dB 13666. 30 dB 13667. ______determines the number of sideband components in FM. carrier frequency modulation frequency modulation index deviation ratio 13668. One of the following transmits only one sideband. H3E R3E A3E B8E 13669. What produces the sidebands on FM? signal amplitude carrier harmonics baseband frequency broadband frequency 13670. Which test instrument displays the carrier and the sidebands amplitude with frequency to frequency? oscilloscope spectrum analyzer frequency analyzer amplitude analyzer 13671. Mixer is also known as a ______. modulator suppressor converter beater 13672. Which one of the following emission transmits the lower sideband and half of the upper sideband? A5C J3E A3J A3H 13673. An FM receives signal ______. vary in amplitude with modulation vary in frequency with modulation vary in frequency and amplitude with wideband modulation is not immune to noise 13674. The process of impressing intelligence on the carrier is called modulation detection mixing impression 13675. ______is an electronic instrument used to show both the carrier and the sidebands of a modulated signal in the frequency domain. spectrum analyzer oscilloscope digital counter frequency counter 13676. What part of the carrier is varied by the intelligence during modulation in an AM system? phase frequency amplitude both a and c 13677. The difference between the RF carrier and the modulating signal frequencies is called the USB LSB Sideband Carrier frequency 13678. What stage in a radio transmitter isolates the oscillator from the load? Oscillator Buffer Separator Mixer 13679. The frequency of the unmodulated carrier in FM system is modulating frequency center frequency carrier frequency deviation frequency 13680. The ratio of maximum deviation to the maximum modulating frequency is called carrier swing deviation ratio modulation factor modulation index 13681. A carrier signal has constant amplitude a frequency of 20 kHz and above a varying amplitude the information content 13682. The modulated peak value of a signal is 125 V and the unmodulated carrier value is 85 V. What is the modulation index? 0.47 0.68 0.32 1.47 13683. An 891 kHz carrier having an amplitude of 80 V is modulated by a 4.5 kHz audio signal having an amplitude of 45 V. The modulation factor is 0.56 0.65 1.78 1.25 13684. What is the modulation index of an FM signal having a carrier swing of 75 kHz when the modulating signal has frequency of 3 kHz? 25 12.5 0.04 0.08 13685. In a FM system, if modulation index is doubled by having the modulating frequency, what will be the effect on the maximum deviation? No effect Maximum deviation doubles Decreases by ½ Increases by ¼ 13686. Which of the following is considered as an indirect method of generating FM? Reactance modulator Balanced modulator Varactor diode modulator Armstrong system 13687. To generate an SSB or DSB signal one must use a circuit known as filter modulator ring modulator balanced modulator reactance modulator 13688. Which is the first radio receiver? TRF receiver Superheterodyne receiver receiver Heterodyne receiver 13689. An interfering signal with a frequency equal to the received signal plus twice the IF is called image frequency center frequency rest frequency interference frequency 13690. Double sideband full carrier emission type 13691. A3J 13692. H3E 13693. R3A 13694. A3E 13695. Single sideband reduced carrier emission type H3E R3E J3E B8E 13696. A single sideband suppressed carrier emission type. H3e R3E J3E B8E 13697. Independent sideband emission type H3E R3E J3E B8E 13698. Vestigial sideband emission type C3F J3E R3E B8E 13699. Single sideband full carrier emission type. R3E H3E J3E B8E 13700. Phase modulation emission type. F3E F3C F3F G3E 13701. Which one is not an advantage of SSB over AM? Power saving Requires half the bandwidth Wider area of reception Better fidelity 13702. The advantage of a high level modulated AM transmitter is Less audio power required Better fidelity Higher value of operating power Less distortion 13703. The advantage of a low-level modulated AM transmitter is Less audio power required Better fidelity Higher value of operating power Less distortion 13704. _____ is the bad effect caused by overmodulation in AM transmission. Increase in noise Deviation in the operating frequency Interface to other radio services Decrease in the output power 13705. Which characteristic of a radio receiver refers to its ability to reject an unwanted signal? Sensitivity Selectivity Fidelity Quality 13706. What type of emission is frequency modulation? F3E G3E A3E B3E 13707. AM transmission power increases with ______. Frequency Source Load Modulation 13708. ______locks the FM receiver to a stronger signal. Hall effect Capture effect Image frequency Homing 13709. What is the highest percentage of modulation for AM? 50% 75% 100% 80% 13710. In FM, the Carson’s Rule states that the bandwidth is equal to twice the sum of the modulating frequency and ______. Carrier signal Modulating signal Frequency deviation Image frequency 13711. What is the carrier swing of an FM transmitter when modified by 75%? 53.2 kHz 48 kHz 56.25 kHz 112.5 kHz 13712. The modulation system inherently more resistant to noise Single sideband suppressed carrier Frequency modulation Pulse-position modulation Amplitude shift keying 13713. Subcarriers that are arranged so that the channels occupying adjacent frequency bands with some frequency space between them is known as Guard bands AM bands Band gap Void band 13714. Modulation of an RF amplifier carrier results in Multiple channels Smaller antennas Directional propagation All of the above 13715. A process which occurs in the transmitter Mixing Modulation Heterodyning Demodulation 13716. A process which occurs in the receiver Beating Modulation Mixing Demodulation 13717. One part of the transmitter that protects the crystal oscillator from “pulling”. Buffer amplifier Modulator Power amplifier Antenna coupler 13718. What aspect of the carrier is changed by modulation? Frequency Phase Amplitude Depends on the type of modulation 13719. The amplitude of a sine wave which is modulated by a musical program will Be complex Contain fundamental frequencies Contain harmonic frequencies All of the above 13720. What will be the result of the gain level being too high for signals entering the modulator? Receiver noise Excessive volume of receiver output Oscillator disturbances Distortion and splatter 13721. Amplitude modulation causes the amount of transmitter power to Increase Decrease Remain the same Double 13722. When a carrier is modulated 100%, the total power increases by what percentage over that of the carrier alone? 25% 50% 75% 100% 13723. When the amplitude of the modulating voltage is increased for AM, the antenna current will Increase Decrease Remain constant Decrease exponentially 13724. An increase in transmitter power from 25W to 30W will cause the antenna current to increase from 700mA to 800 mA 750 mA 767 mA 840 mA 13725. A second modulating tone having the same amplitude but a different frequency is added to the first at the input to the modulator. The modulation index will be increased by a factor of √3 √2 2 3 13726. A 1000 kHz carrier is modulated by a 2500Hz tone. One frequency component of the modulated signal is 1200 Hz 5000 Hz 1002.5 kHz 2500 Hz 13727. A 1200 kHz carrier is amplitude-modulated by two tones of 500 Hz and 700 Hz. Which one is a frequency component of the modulated wave? 1195 kHz 1199.3 kHz 1199.7 kHz 1205 kHz 13728. Identify a modulation method, or methods in use for a common-emitter configuration Base modulation Emitter modulation Collector modulation Both A and C 13729. The RF signal injected into a balanced modulator is 10MHz and the modulating frequency is 1 kHz. Which frequency, or frequencies, will not appear in the output? 9.999 MHz 10 MHz 10.0001 MHz Both A and B 13730. Unwanted sidebands in SSB equipment can be suppressed by one or more of the following methods. Phasing method Filter method Decoder method Both A and B 13731. Envelope detection is concerned with the process of Mixing Heterodyning Modulation Rectification 13732. Diagonal clipping in envelope detection will result in Distortion Phase reversal Reduced sensitivity Amplitude damage 13733. Product detection requires the process of Rectification Heterodyning Decoding Phase shifting 13734. A sine wave which is coherent with carrier has identical Amplitude Frequency Phase angle Both B and C 13735. Frequency modulation and phase modulation are collectively referred to as Stereo Angle modulation High fidelity modulation FCC modulation 13736. In FM, the change in carrier frequency is proportional to what attribute of the modulating signal? Angle Frequency Amplitude Tone 13737. A louder sound, when generating the modulating waveform for FM, will cause a greater Carrier amplitude Angle amplitude Distortion at the receiver Frequency deviation 13738. If a positive change in modulation signal level of 200 mW will cause a positive frequency deviation of 10 kHz, what will be the frequency deviation for a negative change of 10 mV in the level of the modulating signals? 0 -5 kHz +5 kHz +0 kHz 13739. A particular 15 kHz modulation tone results in a peak frequency deviation of 75 kHz. What is the modulation index? 5 15 75 3 13740. A 15 kHz sine wave frequency modulates an 88 MHz carrier. A sideband frequency will be found at 87.970 MHz 87.985 MHz 88.015 MHz All of these 13741. A device whose capacitance is deliberately made to be a function of the applied voltage Varactor diode UJT SAW Variable capacitor 13742. A reactance modulator is one method of obtaining Indirect FM Direct FM Demodulation Low frequency filtering 13743. A device, now available in IC form, is useful for direct FM and as one element in the phse-locked loop. AFC AGC VCO LPF 13744. _____ is a frequency change process, whereby the phase deviation and frequency deviation are multiplied by some fixed constant. Translation Multiplication Division Addition 13745. A circuit that has the function of demodulating the frequency-modulated signal. AFC Envelope detector Decoder Foster-Seeley discriminator 13746. The ratio detector is superior to the slope detector because It is less sensitive to phase modulation It is less sensitive to noise spikes It is less sensitive to interference causing AM Both B and C 13747. One implementation of a pulse averaging discriminator is A free-running multivibrator A crystal-controlled oscillator A quartz crystal filter A triggered multivibrator 13748. A 10% increase in the frequency of a constant-width pulse train should cause what change in its average value? -10% -1% +1% +10% 13749. Two different signals can be coherent if they Have the same amplitude Are both sine waves of different frequencies Originate in the same physical equipment simultaneously Have the same frequency 13750. A quadrature detector requires that Four gates bee provided The inputs are coherent The inputs are incoherent The inputs are identical 13751. In a phase-locked loop, the VCO is the abbreviation for Variable coherent output VHF communication oscillator Voltage-controlled oscillator Vien-count oscillator (neutralized) 13752. Identify an advantage, or advantages of a properly designed FM system. Relative immunity to atmospheric noise (lightning) Reduced bandwidth required No noise of any kind The noise figure is inversely proportional to the modulation index 13753. The output of a balanced modulator LSB and USB LSB USB Carrier 13754. If the modulation index of an AM wave is changed from 0 to 1, the transmitted power is Unchanged Halved Doubled Increased by 50% 13755. Which of the following is not a baseband signal of modulation? Audio signal Video signal RF carrier Binary coded pulses 13756. If the unmodulated level peak carrier amplitude is doubled in an AM signal, the perfect modulation is ______. 20 50 100 200 13757. Balanced modulator circuit when inserted in the equivalent suppresses the ______Carrier Upper sideband Lower sideband Baseband signal 13758. The carrier of a 100% modulated AM wave is suppressed, the percentage power saving is __. 100% 50% 83% 66.66% 13759. If the modulation index if an AM wave is doubled, the antenna current is also doubled, the AM system being used is H3E J3E C3F A3E 13760. 100% modulation in AM means a corresponding increase in total power by ______. 100% 50% 75% 25% 13761. A single-tone amplitude modulated wave has ______. 2 components 3 components 4 components 2n + 1 components 13762. A carrier signal has ______. Constant peak amplitude Frequency range of 20 – 20,000 Hz A varying amplitude The information 13763. The modulating system is ______if the modulating frequency is doubled, the modulation index is halved, and the modulating voltage remains constant. Amplitude modulation Phase modulation Frequency modulation Pulse modulation 13764. What is the modulation index of an FM signal if its modulating frequency is doubled? No effect Twice the original index Four times the original index One-half the original index 13765. An AM transmitter is rated 1000 W at 100% modulation. How much power required for the carrier? 1000 W 666.6 W 333.3 W 866.6 W 13766. Standard way of designating AM A3E B3E AHE C3F 13767. _____ is the circuit used to detect frequency modulated signal. Discriminator Modulator Modem Detector 13768. _____ is an information signal that is sent directly without modulating any carrier. C-band Q-band Baseband Broadband 13769. Both frequency and phase modulation utilize ______modulation. Digital Phase Amplitude Angle 13770. It is the width of frequencies within the spectrum occupied by a signal and used by the signal for conveying information. Band Bandwidth Electronic spectrum Frequency band 13771. Which transmit only one sideband? H3E C3F A3E B8E 13772. ______is kind of modulation in which the modulated wave is always present. Carrier modulation Continuous modulation Log-periodic modulation Square-wave modulation 13773. A type of modulation in which no signal is present between pulses. Pulse modulation FSK QAM PAM 13774. What describes the amount of amplitude change present in an AM waveform? Percent modulation Modulation constant Envelope of modulation Coefficient of modulation 13775. ______is a form of amplitude distortion introduced when the positive and negative alternations in the AM modulated signals are not equal. Envelope distortion Spurious emission Carrier shift Johnson noise 13776. What is the advantage of phase modulation over direct FM frequency modulation? Multipliers can be used The deviation is smaller Simplicity and practicality The oscillator is crystal-controlled 13777. If the spectrum is shifted in frequency with no other changes, this is known as Frequency multiplication Sideband movement Baseband reorientation Frequency translation 13778. A device which is capable of causing frequency translation High-Q tank circuit Balanced modulator Low-Q tank circuit IF strip 13779. If the frequency of each component in a signal spectrum is increased by the same fixed amount, this known as Modulation Frequency translation Up conversion Both B and C 13780. A particular amplifier is designed to be a frequency doubler. If the input signal frequency is 15.4 MHz, a circuit in the output will be tuned to 7.7 MHz 15.4 MHz 30.8 MHz 61.6 MHz 13781. A sine wave of 293 MHz is phase-modulated to achieve a maximum phase deviation of 0.2 radian. After passing through a frequency tripler, the maximum phase deviation will be 0.2 radian 0.3 radian 0.4 radian 0.6 radian 13782. Any device to be used as a frequency multiplier must be Active Passive Linear Nonlinear 13783. A particular amplifier circuit used for frequency doubling. Push-push Push-pull Pull-push Pull-pull 13784. Frequency division is useful in the implementation of a AM demodulator Frequency synthesizer AGC circuit FM demodulator 13785. Frequency division by 12 will require how many flip-flops in the counter? 3 4 6 12 13786. Identify an electronic device, not specifically designed for the purpose, which can be used as a phase detector. Wien bridge Colpitts oscillator Balanced modulator Butterworth filter 13787. A particular frequency synthesizer contains only a single crystal. What words describe this synthesizer? Crystal modulated Inexact Indirect Deficient 13788. A recognizable feature of a CW transmitter is Keyed transmitter Power amplification Frequency generation All of these 13789. The term “pulling” refers to The change of the crystal oscillator frequency by loading One half-cycle operation of a push-pull amplifier Loading on the transmitter caused by the antenna connection Reduction of the power supply terminal voltage as the transmitter is keyed. 13790. When frequency modulation is achieved by initial phase modulation, this is called Angular modulation Direct FM Indirect FM Indirect synthesis 13791. A disadvantage of direct FM is the need for AGC AFC A frequency synthesizer Phase modulation 13792. Direct FM can be achieved by A reactance tube modulator A varactor diode And AGC circuit Both A and B 13793. A receiver in which all RF amplifier stages require manual tuning to the desired RF is called Superheterodyne Autodyne TRF AFC 13794. Why is it often necessary to precede the demodulator by amplifier stages in a receiver? To improve fidelity To reduce receiver noise To eliminate image response Weak antenna signals 13795. A serious disadvantage of the TRF receiver. Bandwidth variations over the tuning range The weight and cost The requirements for a closely regulated power supply The requirements for a half-wave antenna 13796. Identify which is not a part of a superheterodyne receiver. Local oscillator Modulator IF amplifier Demodulator 13797. Which major element will not be found in every superheterodyne receiver? R–F amplifier Mixer Local oscillator IF amplifier 13798. Which major element of a superheterodyne receiver must be nonlinear? R-F amplifier Mixer Local oscillator IF amplifier 13799. The change of the modulated carrier frequency from the original RF to the IF of the superheterodyne receiver is known as Frequency multiplication Frequency allocation Frequency substitution Frequency translation 13800. The key to achieving receiver sensitivity is the reduction of Image response Mixer harmonic products Spurious frequency response Internal noise 13801. Which of the following receiver design objectives is not impossible? Elimination of galactic noise Elimination of atmospheric noise Elimination of man-made noise Reduction of receiver internal noise 13802. In comparing the S/N ratio for the input to the receiver with the S/N ratio for the output, the latter is Smaller The same Greater Infinite 13803. The characteristic of a receiver that specifies the self-generated noise. Noise immunity Noise factor Noise figure Noise margin 13804. An FM receiver with an I-F of 10.7 MHz is tuned to 98.7 MHz. What is the numerical value of the image frequency? 77.3 MHz 88.0 MHz 109.4 MHz 120.1 MHz 13805. A source of RF interference exists at 109.9 MHz. For which frequency in the FM broadcast band will this be the image frequency? 21.4 MHz 88.5 MHz 99.2 MHz 110.7 MHz 13806. The ratio of the superheterodyne receiver response at the desired carrier frequency to that at the image frequency is called The sensitivity The selectivity The image frequency The image rejection ratio 13807. The core of an IF transformer usually contains Teflon Computer nylon Powdered iron Laminated steel 13808. Shape factor is a measure of Bandwidth Skirt steepness Coupling coefficient Critical coupling 13809. ______is the function which tends to maintain the sound volume level of a voice receiver nearly constant for a large signal strength range. Squelch Muting AGC AFC 13810. The function which tends to silence the receiver in the absence of transmitted carrier. Squelch Muting AGC AFC 13811. What device is incorporated in a communications receiver to reduce impulse noise? Front-end processor Squelch circuit AGC Noise blanker 13812. What type of signal in which a receiver selectivity of 2.4 kHz in the I-F circuitry is optimum? FM voice Double-sideband AM voice FSK data SBB voice 13813. If the input to a detector stage is an amplitude-modulated (A3E) IF signal then the output from the stage is A lower frequency carrier The audio voice information A Morse-code signal The upper or lower set of sidebands 13814. In a capacitive type, reactance-tube modulator connected across an oscillator tuned circuit, a more negative voltage on the grid of the reactance tube will cause An increase of the oscillator frequency An decrease of oscillator frequency An increase of the reactance-tube capacitance An increase of the reactance tube ac plate current 13815. The limiting condition for sensitivity in a communications receiver is The noise floor of the receiver Power supply output ripple The two-tone intermodulation distortion The input impedance to the detector 13816. When a communications receiver is tuned to a strong signal, the AGC bias is measured and found to be zero. The fault cannot be caused by a/an Defective IF stage Defective local oscillator Defective RF stage Open circuit in the AGC’s filter capacitor 13817. The term used to refer to the condition where the signals from a very strong station are superimposed on other signals being received Cross-modulation interference Intermodulation interference Receiver quieting Capture effect 13818. The limiter stage of an FM receiver Behaves as a low-pass filter Limits the amplitude of the IF signal to the required level Behaves as a high-pass filter Behaves as a bandstop filter 13819. Motorboating (low-frequency oscillations) in an amplifier can be stopped by Grounding the screen grid Connecting a capacitor between the B+ and lead ground By passing the screen grid resistor with a 0.1 µF capacitor Grounding the plate 13820. An effect in which, the modulation of an unwanted signal is transferred to the desired carrier. Crossmodulation Intermodulation Modulation mixing Image-channel interference 13821. Leads should be kept as short as possible in radio circuit so that Skin effect is reduced There is less hysteresis effect There is less dielectric loss Stray coupling is minimized 13822. The number of voice transmissions that can be packed into a given frequency band for amplitude-compandored single-sideband systems over conventional FM-phone systems. 2 18 16 4 13823. Neutralization of an RF amplifier stage can be necessary in order to Increase the amplifier’s gain Prevent the generation of spurious oscillations Reduce the amplifier’s gain Reduce the level of the output harmonics 13824. The ability of a communications receiver to perform well in the presence of strong signals outside the band of interest is indicated by what parameter? Blocking dynamic range Noise figure Signal-to-noise ratio Audio output 13825. Stages that are common to both AM and FM receivers Tuner, local oscillator, detector, AF amplifier RF amplifier, mixer, IF amplifier, AF amplifier Local oscillator, RF amplifier, frequency discriminator, detector Tuner, IF amplifier, detector, AF amp 13826. Occurs during CW reception if too narrow a filter bandwidth is used in the IF stage of a receiver Filter ringing Undesired signals will reach the audio stage Output-offset overshoot Cross-modulation distortion 13827. What stage mainly determines a communication receiver’s sensitivity? IF amplifier Mixer stage Detector stage RF amplifier 13828. What is the main advantage of FM over AM? Better signal-to-noise-ratio Narrower bandwidth Greater propagation range Total freedom from adjacent-channel interference 13829. An amplitude modulation created in an amplifier before the final RF stage. Low-level modulation High-level modulation Direct modulation Indirect modulation 13830. Receiver desensitizing can be reduced by Increasing the transmitter audio gain Decreasing the receiver squelch gain Increasing the receiver bandwidth Ensuring good RF shielding between the transmitter 13831. In a narrow-band FM system, the deviation ratio is commonly one and the highest audio frequency is generally limited to 300 Hz 10,000 Hz 3,000 Hz 7,500 Hz 13832. A type of emission is produced when an amplitude modulated transmitter is modulated by a facsimile signal A3F F3F A3C F3C 13833. Where is the noise generated which primarily determines the signal to noise ratio in a VHF (150 MHz) marine band receiver? In the detector In the atmosphere In the ionosphere In the receiver front end 13834. Cross-modulation in a receiver can be reduced by Installing a filter at the receiver Using a filter at the receiver Increasing the receiver’s RF gain while decreasing the AF Adjusting the pass-band tuning 13835. What is the emission designation for FM telephony? F3E G3E J3E H3E 13836. What is the cause of receiver desensitizing? The presence of a strong signal on a nearby frequency Audio gain adjusted too low Squelch gain adjusted too high Squelch gain adjusted too low 13837. In a phase-modulated signal (indirect FM), the frequency deviation is directly proportional to the Carrier amplitude only Amplitude of the modulating tone and frequency of the carrier Carrier frequency only Modulating signal amplitude only 13838. An RF stage precedes the mixer stage in a superhet receiver. One advantage of including this RF stage is Better selectivity Better rejection ratio Greater sensitivity Improved signal-to-noise-ratio 13839. Two factors that determine the sensitivity of a receiver. Dynamic range and third-order intercept Cost and availability Bandwidth and noise figure Intermodulation distortion and dynamic range 13840. What is an undesirable effect of using too-wide a filter bandwidth in the IF section of a receiver? Undesired signals will reach the audio stage Output-offset overshoot Thermal-noise distortion Filter ringing 13841. A system containing a limiter stage, a discriminator, and a de-emphasis circuit? Direct FM transmitter Indirect FM transmitter Single sideband AM receiver FM receiver 13842. The limiter stage of an FM receiver Prevents any amplitude modulation of the IF signal Limits the amount of frequency deviation in the IF signal Limits the overall bandwidth of the IF stages Corrects any deviation in carrier frequency 13843. High selectivity occurs when the degree of coupling between a receiver’s RF stages is Tight Loose Critical Adjusted for maximum power transfer 13844. A carrier is phase modulated by a test tone. If the amplitude and the frequency of the tone are both doubled, the amount of the deviation is Doubled Unchanged Halved Multiplied by four 13845. The degree of selectivity desirable in the IF circuitry of a single-sideband receiver. 1 kHz 2.4 kHz 4.2 kHz 4.8 kHz 13846. The component most apt to break down in the radio circuit is the Crystal Resistor Transformer Diode 13847. The base in an RF amplifier is grounded in order to Avoid the requirement of neutralizing the stage Raise the input impedance Lower the output impedance Obtain maximum power output 13848. The AM detector performs two basic functions in the receiver. Rectifies and filters Amplifiers and filters Buffer and amplifier Buffer and detector 13849. A varactor diode can be used in a/an Direct FM modulator circuit AFC circuit in a direct FM transmitter Phase-modulator circuit All of these 13850. Receiver interference is not reduced by including a/an Crystal filter Insulating enclosures around the receiver Wave trap RF stage 13851. What is the emission C3F? RTTY SSB Television Modulated CW 13852. What is the approximate dc input power to a class AB RF power amplifier stage in an unmodulated carrier transmitter when the PEP output is 500 W? Approximately 1000 W Approximately 800 W Approximately 250 W Approximately 600 W 13853. Which of the following stages in an FM receiver is responsible for drastically reducing the effect of static noise during the reception of a signal De-emphasis circuit Mixer stage Squelch circuit Limiter stage 13854. The letters “SSSC” stands for Single sideband, single carrier Suppressed sideband, single channel Suppressed sideband, single carrier Single sideband, suppressed carrier 13855. For many types of voices, what is the ratio of PEP-to-average power during a modulation peak in a single-sideband phone signal? Approximately 1.0 to 1 Approximately 25 to 1 Approximately 100 to 1 Approximately 2.5 to 1 13856. In most mixers, the oscillator frequency is ______than the carrier frequency of the input signal. Higher Lower The same 10 kHz above 13857. Features of a transmitter’s buffer stage include High stage Harmonic generation Improvement in frequency stability of the oscillator Low input impedance 13858. Type of emission produced when an amplitude modulated transmitter is modulated by a television signal F3F A3C F3C A3F 13859. A network is A network consisting entirely of four inductors or four capacitors A power incidence network An antenna matching network that is isolated from ground A network consisting of one inductor and two capacitors 13860. How is G3E FM-phone signals produced? A network consisting modulator on the audio amplifier With a reactance modulator on the final amplifier With a reactance modulator on the oscillator With a balanced modulator on the oscillator 13861. A way of eliminating auto interference to radio reception Installing resistive spark plugs Installing capacitive spark plugs Installing resistors in series with the spark plugs Installing two copper-braid ground strips 13862. The carrier in an AM transmitter is the Transmitter’s output signal when the modulation is present Transmitter’s output signal when the modulation is zero Output signal from the crystal oscillator RMS value of the AM signal 13863. What stage feeds the discriminator of an FM receiver? Local oscillator Mixer stage Final IF amplifier, which also acts as a limiter stage Buffer 13864. In an FM receiver, the stage that has the IF signal is input and the audio signal output. Limiter Audio amplifier IF amplifier Discriminator 13865. What is capture effect? All signals on a frequency are demodulated by an FM receiver The loudest signal received is the only demodulated signal All signals on a frequency are demodulated by an AM receiver The weakest signal received is the only demodulated signal 13866. A double-sideband phone signal can be generated by Feeding a phase-modulated signal into a low-pass filter Modulating the plate voltage of a class-C amplifier Using a balanced modulator followed by a filter Detuning a Hartley oscillator 13867. Pre-emphasis is used in FM transmitters to improve the signal-to-noise ratio of High modulating frequencies Low modulating frequencies All modulating frequencies Frequencies carrier 13868. The result of cross-modulation is that The modulation of an unwanted signal is heard on the desired signal A decrease in modulation level of transmitted signals Of receiver quieting Of inverting sidebands in the final stage of the amplifier 13869. Which of the following contains de-emphasis circuit? FM transmitter FM receiver VHF transmitter VHF receiver 13870. What is emission F3F? AM Facsimile Television RTTY 13871. What type of emission is produced when a frequency modulated transmitter is modulated by a facsimile signal? F3C A3C F3F A3F 13872. Two AM transmitting antennas are close together. As a result the two modulated signals are mixed in the final RF stage of both transmitters. What is the resultant effect on other station? Harmonic interference Intermodulation interference Spurious interference Crossmodulation interference 13873. The term used to refer to the reduction of receiver gain caused by the signal of a nearby station transmitter in the same frequency band? Quieting Cross-modulation interference Squelch gain rollback Desensitizing 13874. What is the bandwidth occupied by the carrier, both sidebands and harmonics? Authorized bandwidth Bandwidth of emission and occupied bandwidth Operating bandwidth All of these 13875. A class-C RF amplifier is collector amplitude modulated and its average dc level collector current does not change. This means A normal condition Excessive drive to the base Insufficient drive to the base Insufficient audio modulation 13876. What determines the percentage modulation of an FM transmitter? Amplitude of the carrier Modulating frequency Carrier frequency Amplitude of the modulating signal 13877. Deviation ratio of an FM transmitter is the ratio of the Maximum frequency swing to the highest modulating frequency Operating frequency of the assigned frequency Frequency swing to the modulating frequency Highest modulating frequency to the minimum frequency 13878. The main purpose of the beat frequency oscillator (BFO) is to generate A 1 kHz not for Morse reception Aid in the reception of weak voice-modulated signals An output, whose frequency differs from the IF by 1 kHz A signal, whose frequency is the same as intermediate frequency 13879. Normally, a linear class BRF power amplifier operates with a bias approximately equal to Twice cut-off Ten times cut-off value 50% of cut-off value Projected cut-off 13880. The purpose why an RF amplifier is operated under linear class-B conditions (as opposed to class-C) is to Generate only even harmonics Generate only odd harmonics Increase the efficiency Amplify of an AM signal 13881. The term used to refer to the condition where the signal from a very strong station are superimposed on other signal being received. Cross-modulation interference Intermodulation distoriotion Receiver quieting Capture effect 13882. ______is the amplitude of the maximum negative excursion of a signal as viewed on an oscilloscope. Peak-to-peak voltage Inverse peak positive voltage RMS voltage Peak negative voltage 13883. The type of emission that suffer most from selective fading. CW and SSB SSB and TV FM and double sideband AM SSTV and CW 13884. In an FM-phone signal, ______is the ratio between the actual frequency deviation to the maximum frequency deviation. FM compressibility Modulating index Percentage of modulation Quieting index 13885. ______is used to refer to the reception blockage of one FM-phone signal by another FM-phone signal. Capture effect Desensitization Cross-modulation interference Frequency discrimination 13886. A receiver selectivity of 10 kHz in the IF circuitry is optimum for what type of singals? SSB voice Facsimile FM Double-sideband AM 13887. If the envelope of modulation is constant in amplitude this means Zero beat Under-modulation Zero-modulation Over-modulation 13888. What is the approximate bandwidth of an FM with a modulation factor of 12.5 and a modulating frequency of 10 kHz? 20 kHz 270 kHz 250 kHz 45 kHz 13889. Amplitude modulation is the same as Linear mixing Analog multiplication Signal summation Multiplexing 13890. The negative half of the AM wave is supplied by a/an ______on a diode modulator. The tuned circuit Transformer Capacitor Inductor 13891. One of the following can produce AM. Having the carrier vary a resistance Having the modulating signal vary a capacitance Varying the carrier frequency Varying the gain of an amplifier 13892. Amplitude modulators that vary the carrier amplitude with the modulating signal by passing it through an attenuator network is the principle of Rectification Amplification Variable resistance Absorption 13893. Which component is used to produce AM at very high frequencies? Varactor diode Thermistor Cavity resonator PIN diode 13894. A collector modulator has a supply voltage of 48 V. What is the peak-to-peak amplitude of the modulating signal for 100 percent modulation? 24 V 48 V 96 V 120 V 13895. What circuit recovers the original modulating information from an AM signal? Modulator Demodulator Mixer Crystal set 13896. What is the most commonly used amplitude demodulator? Envelope detector Balanced modulator Mixer Crystal set 13897. What circuit generates the upper and lower sidebands and suppresses the carrier? Amplitude modulator Diode detector Class C amplifier Balanced modulator 13898. ______is a widely used balanced modulator. Diode bridge circuit Full-wave bridge rectifier Lattice modulator Balanced bridge modulator 13899. In a diode ring modulator, the diodes act like Variable resistors Switches Rectifiers Variable capacitors 13900. The output of a balanced modulator is AM FM SSB DSB 13901. The principal circuit in the popular 1496/1596 IC balanced modulator is a Differential amplifier Rectifier Bridge Constant current source 13902. The most commonly used filter in SSB generators uses LC networks Mechanical resonators Crystals RC networks and op amps 13903. In the phasing method of SSB generation, one sideband is canceled out due to Phase shifting Sharp selectivity Carrier suppression Phase inversion 13904. A balanced modulator used to demodulate a SSB signal is call a/an Transponder Product detector Converter Remodulator 13905. Frequency translation is done with a circuit called a Summer Multiplier Divider Mixer 13906. Mixing for frequency conversion is the same as Rectification AM Linear summing Filtering 13907. Which of the following is not a major advantage of FM over AM? Greater efficiency Noise immunity Capture effect Lower complexity and cost 13908. The primary disadvantage of FM is its Higher cost and complexity Excessive use of spectrum space Noise susceptibility Lower efficiency 13909. Noise is primarily High-frequency spikes Lowe-frequency variations Random level shifts Random frequency variations 13910. The receiver circuit that rids FM of noise is the Modulator Demodulator Limiter Low-pass filter 13911. The AM signals generated at a low level may only be amplified by what type of amplifier? Class A Class B Class C All of the above 13912. SSB means Single sideband with suppressed carrier Single sideband with carrier Double sideband with no carrier Single sideband with reduced carrier 13913. A circuit used to select the desired output from a mixer Transformer Resonant circuit Filter Phase-shift circuit 13914. What is the output of a balanced modulator? AM DSB SSB ISB 13915. The acronym SSSC refer to Suppressed sideband, single carrier Suppressed sideband, suppressed carrier Single sideband, suppressed carrier Single sideband, single carrier 13916. Which process occurs in the receiver? Demodulation Reception Modulation Recreation 13917. What is usually used to demodulate SSB or CW signal? PLL BFO Ratio detector All of these 13918. Which of the following is the most widely used amplitude modulator Diode detector PLL circuit VCO All of these 13919. Which of the following is the most widely used balanced modulator Full-wave bridge circuit Balanced bridge modulator Lattice modulator None of these 13920.

13921. [Type the document title]

13922. [Type the document subtitle] 13923. 13924. H 13925.

13926. 13927. 13928. 13929.

1. 13930. 13931. 13932. 13933. ECE BOARD PROBLEMS 13934. APRIL 1999 – NOVEMBER 2002 13935. 13936. 13937. (ECE Board Problem, November 2001) “Compulsory interconnection” 13938. 13939. a.) EO 59 13940. b.) EO 546 13941. c.) EO 109 13942. d.) Act 3846 13943. 13944. (ECE Board Problem, November 2002) A single measuring circuit having a resistor if 10 kΩ is connected in series with a 0.5 μF capacitor. What is affective bandwidth? 13945. 13946. a.) 50 kHz 13947. b.) 5 Hz 13948. c.) 50 Hz 13949. d.) 500 Hz 13950. 13951. (ECE Board Problem, April 1999) An aircraft deviation measured by an ILS localizer. 13952. 13953. a.) Altitude 13954. b.) Ground Speed 13955. c.) Vertical 13956. d.) Horizontal 13957. 13958. (ECE Board Problem, November 2001) In order to have a maximum power transfer, what must be the relation of the input circuit impedance? 13959. 13960. a.) Equal Impedance 13961. b.) Infinity 13962. c.) Zero 13963. d.) Less Than 13964. 13965. (ECE Board Problem, November 2001) The ratio of the speed of the light in vacuum to the speed of the light in a material. 13966. 13967. a.) Index of Refraction 13968. b.) Dielectric Constant 13969. c.) Velocity Factor 13970. d.) Permittivity 13971. 13972. 13973. 13974. 13975. 13976. (ECE Board Problem, November 2001) What is the radiation pattern of a half – wave dipole? 13977. 13978. a.) Doughnut Shape 13979. b.) Bi-Directional 13980. c.) Unidirectional 13981. d.) Omnidirectional 13982. 13983. 13984. (ECE Board Problem, November 2001) It is produced when an object travels faster than the speed of sound. 13985. 13986. a.) Shock Wave 13987. b.) Ultrasound 13988. c.) Sonic Wave 13989. d.) Light Wave 13990. 13991. (ECE Board Problem, November 2001) The time used for reference for determining the capacity of accepting calls for telephone system. 13992. 13993. a.) 12 MN 13994. b.) High Usage Hour 13995. c.) 12NN 13996. d.) Low Usage Hour 13997. 13998. (ECE Board Problem, November 2001) The term used for deafness of higher frequencies due to old age. 13999. 14000. a.) Ear Deafness 14001. b.) Cortial Deafness 14002. c.) Tinnitus 14003. d.) Presbycusis 14004. 14005. (ECE Board Problem, November 2002) Single side band emission is most frequently used in what frequency band? 14006. 14007. a.) LF 14008. b.) HF 14009. c.) MF 14010. d.) VLF 14011. 14012. (ECE Board Problem, November 2001) A device that converts voice to data. 14013. 14014. a.) Vocoder 14015. b.) Covoder 14016. c.) Modern 14017. d.) Repeater 14018. 14019. (ECE Board Problem, November 2001) A microwave device which permits signal only in one direction. 14020. 14021. a.) RF Emitter 14022. b.) Capacitor 14023. c.) Varactor and triac 14024. d.) Ferrite Isolator 14025. 14026. 14027. (ECE Board Problem, November 2001) A very small band of frequency that is used to protect interference of adjacent frequency. 14028. 14029. a.) Guard 14030. b.) Carrier 14031. c.) Modulating 14032. d.) Tolerance 14033. 14034. (ECE Board Problem, November 2001) It is a communication system operation where the receiving station controls the effective data transmission rate at the sending station. 14035. 14036. a.) Pacing 14037. b.) Polling 14038. c.) Handshaking 14039. d.) Contention 14040. 14041. (ECE Board Problem, November 2001) Where is the AGC in the IF amplifier derived? 14042. 14043. a.) Mixer 14044. b.) Rf Amplifier 14045. c.) Detector 14046. d.) Local Oscillator 14047. 14048. (ECE Board Problem, November 2002) What is the voltage in a line, open terminated at the end, quarter-wavelength from the termination? 14049. 14050. a.) Minimum 14051. b.) Maximum 14052. c.) The same 14053. d.) Increasing 14054. 14055. (ECE Board Problem, November 2001) What is the cellular system used in Europe? 14056. 14057. a.) GSM 14058. b.) TACS 14059. c.) AMPS 14060. d.) NMT 14061. 14062. (ECE Board Problem, November 2001) Satellite revolution in the same direction as the earth's rotation. 14063. 14064. a.) Retrograde 14065. b.) Accelerated 14066. c.) Deccelerated 14067. d.) Posigrade 14068. 14069. (ECE Board Problem, November 2001) What is meant by the term radiation resistance of an antenna? 14070. 14071. a.) The resistance in the trap coils to received signal. 14072. b.) An equipment resistance that would dissipate the same amount of power as that radiated from an antenna 14073. c.) The specific impedance of an antenna. 14074. d.) Losses in the antenna elements and feed line. 14075. 14076. (ECE Board Problem, November 2001) How do you connect two digital terminal equipment (DTE) in the absence of a modem? 14077. 14078. a.) Line Bridging. 14079. b.) Direct connection with the use of a null modem. 14080. c.) Sharing of line. 14081. d.) Using a router. 14082. 14083. (ECE Board Problem, April 2002) ______demodulates an FM signal. 14084. 14085. a.) Frequency Discriminator 14086. b.) Frequency Multiplier 14087. c.) Diode Detector 14088. d.) IF Amplifier 14089. 14090. (ECE Board Problem, April 2000) The effect of multi mode propagation caused the rays leaving the fiber to interfere constructively and destructively as they leave the end of the fiber, this effect is called ______. 14091. 14092. a.) multi mode Interference 14093. b.) Modal Delay Spreading 14094. c.) multi mode Effect 14095. d.) Single Modal Effect 14096. 14097. (ECE Board Problem, November 2000)What is the maximum number of lines for any building other than a one or two story residential building to be required a service entrance facility under ECE building code? 14098. 14099. a.) Two Lines 14100. b.) Five Lines 14101. c.) Three Lines 14102. d.) Not Required 14103. 14104. (ECE Board Problem, November 2000) Which of the following is not part of the audio frequency section of the radio transmitter? 14105. 14106. a.) AF Voltage 14107. b.) Microphone 14108. c.) Master Oscillator 14109. d.) AF power Amplifier 14110. 14111. (ECE Board Problem, November 2000) Which of the following solution will you prescribed to a telegraph transmitter power supply to avert a chirp? 14112. 14113. a.) Resonate power supply filters. 14114. b.) Decrease the voltage of power supply. 14115. c.) Regulate the power supply voltage 14116. d.) Decrease current output. 14117. 14118. (ECE Board Problem, April 2000) What is the term for the ratio of actual velocity at which a signal travels through a line to the speed of light in a vacuum? 14119. 14120. a.) Surge Impedance 14121. b.) Characteristics Impedance 14122. c.) Standing Wave Ratio 14123. d.) Velocity Factor 14124. 14125. (ECE Board Problem, April 1999) Which part of the HF marine antenna safety link is intended to be broken during the unusual movement of the ship? 14126. 14127. a.) Halkyard 14128. b.) Weak Part 14129. c.) Mainmast 14130. d.) Foremast 14131. 14132. (ECE Board Problem, November 2002) A PCM has a 30 kHz sampling frequency. What is the maximum input frequency? 14133. 14134. a.) 15 kHz 14135. b.) 60 kHz 14136. c.) 45 kHz 14137. d.) 30 kHz 14138. 14139. (ECE Board Problem, April 1999) What is the capture effect? 14140. 14141. a.) The weak signal received is the only demodulated signal. 14142. b.) All signals on a frequency are demodulated by an AM receiver. 14143. c.) All signals on a frequency are demodulated by an AM receiver. 14144. d.) The loudest signal received is the only demodulated signal. 14145. 14146. (ECE Board Problem, April 2000) Which of the following microwave antenna is normally used when obtaining an omni – directional radiation requirement? 14147. 14148. a.) Grid Type 14149. b.) Whip 14150. c.) Bicone 14151. d.) Parabolic 14152. 14153. (ECE Board Problem, April 1999) What is being measured in RADAR theory to complete the determination of a distance to a target or an object, after a high radio frequency signal is transmitted to a target? 14154. 14155. a.) Transmission time from the source to target. 14156. b.) Transmission time from target back to source. 14157. c.) Echo time of the object to the source. 14158. d.) Complete signal transmission from source and back. 14159. 14160. (ECE Board Problem, April 2000) What is the radio horizon distance between a 150 ft. transmitting station and a 70 ft. receiving station? 14161. 14162. a.) 82.46 mi 14163. b.) 82.46 km 14164. c.) 29.15 km 14165. d.) 29.15 mi 14166. 14167. (ECE Board Problem, November 2000) Telephone channel has a band-pass characteristics occupying the frequency range of _____. 14168. 14169. a.) 300-2700 Hz 14170. b.) 300-3400 Hz 14171. c.) 300-3000 Hz 14172. d.) 300-400 Hz 14173. 14174. 14175. 14176. (ECE Board Problem, November 1999) This the Nordic analogue mobile radio telephone system originally used in Scandinavia. 14177. 14178. a.) NMT 14179. b.) GSM 14180. c.) PCN 14181. d.) PCS 14182. 14183. (ECE Board Problem, April 2000) When a signal bandwidth of a TV broadcast over the radio is lessen, using a technique that limits a picture frequency, this is referred to as ______. 14184. 14185. a.) Video Control 14186. b.) Interlaced Scanning 14187. c.) Demodulation 14188. d.) Line Scanninh 14189. 14190. (ECE Board Problem, April 1999) These are bend of light wavelengths that are too short to be seen by the human eye. 14191. 14192. a.) Visible 14193. b.) Amber 14194. c.) Infrared 14195. d.) Ultraviolet 14196. 14197. (ECE Board Problem, April 2000) How does the length of the director element of a parasitic element beam antenna compare with that of the driven element? 14198. 14199. a.) It is about 5% longer. 14200. b.) It is one-half as long. 14201. c.) It is twice as long. 14202. d.) It is about 5% shorter. 14203. 14204. (ECE Board Problem, November 2001) Refers to the numeric ratio relating to the radiated signal strength of an antenna to that of another antenna. 14205. 14206. a.) Antenna Loss 14207. b.) Antenna Gain 14208. c.) Antenna Bandwidth 14209. d.) Antenna Efficiency 14210. 14211. (ECE Board Problem, November 2001) What will happen if there is a great mismatch between the load and the source? 14212. 14213. a.) High SWR 14214. b.) Low SWR 14215. c.) Medium SWR 14216. d.) SWR of 1 14217. 14218. (ECE Board Problem, November 2001) What is used to connect a computer if it is far from the host? 14219. 14220. a.) Modem 14221. b.) AVR 14222. c.) Waveguide 14223. d.) Transponder 14224. 14225. (ECE Board Problem, November 2001) Range of frequency that an antenna will perform well. 14226. 14227. a.) Antenna Bandwidth 14228. b.) Antenna Beamwidth 14229. c.) Antenna Efficiency 14230. d.) Antenna Directivity 14231. 14232. (ECE Board Problem, November 2001) What is the fastest memory of a computer? 14233. 14234. a.) RAM 14235. b.) Cache 14236. c.) Magnetic Disk 14237. d.) Magnetic Tape 14238. 14239. (ECE Board Problem, November 2001) What composes the electromagnetic waves? 14240. 14241. a.) Electric and Magnetic Field 14242. b.) Acoustic and Water Wave 14243. c.) Current and Voltage 14244. d.) Pressure and Frequency 14245. 14246. (ECE Board Problem, November 2001) One of the characteristics of an early facsimile machine which electromechanical device. 14247. 14248. a.) Receive start/stop bits to synchronize. 14249. b.) Using heat that would burn the image into heat. 14250. c.) Using tubes to amplify the signal. 14251. d.) Using fire to heat the thermal paper. 14252. 14253. (ECE Board Problem, November 2001) What is the cable requirement for one or two-storey building that has more than five telephone lines? 14254. 14255. a.) Service Entrance 14256. b.) Service Cable 14257. c.) Building Cable 14258. d.) Residential Cable 14259. 14260. (ECE Board Problem, November 2001) A transmission line consisting of center conductor, a plastic insulation, a fine wire braid shield and outer plastic insulation as a jacket. 14261. 14262. a.) coaxial cable 14263. b.) twin cable 14264. c.) wave guide 14265. d.) twisted pair 14266. 14267. (ECE Board Problem, November 2001) The executive branch of government in- charge of policy making in telecommunication. 14268. 14269. a.) National Telecommunication Commission 14270. b.) Telecommunication Control Bureau 14271. c.) Department of Transportation and Communication 14272. d.) Bureau of Communication 14273. 14274. (ECE Board Problem, November 2001) What is the dBSPL of an auditorium with contemporary music? 14275. 14276. a.) 95 – 100 dB 14277. b.) 40 – 50 dB 14278. c.) 50 – 60 dB 14279. d.) 70 – 80 dB 14280. 14281. (ECE Board Problem, November 2001) What is the symbol designated for a frequency modulated carrier for a single telephony transmission? 14282. 14283. a.) F3E 14284. b.) F3F 14285. c.) G3F 14286. d.) G3E 14287. 14288. (ECE Board Problem, November 2001) The layer that is responsible for sky wave propagation and the highest layer? 14289. 14290. a.) D 14291. b.) F2 14292. c.) A 14293. d.) E 14294. 14295. (ECE Board Problem, November 2001) Process of impressing lower intelligent frequency to higher frequency. 14296. 14297. a.) modulation 14298. b.) detection 14299. c.) multiplexing 14300. d.) scrambling 14301. 14302. (ECE Board Problem, November 2001) Find the suitable ground plane for a frequency of 220 MHz. 14303. 14304. a.) 0.5 m 14305. b.) 0.24 m 14306. c.) 0.34 m 14307. d.) 1.2 m 14308. 14309. (ECE Board Problem, November 2001) The term used for the mechanism RADAR searchimg for an object. 14310. 14311. a.) scanning 14312. b.) tracing 14313. c.) lobing 14314. d.) nodding 14315. 14316. (ECE Board Problem, November 2001) 14317. 14318. a.) variable capacitance 14319. b.) variable resistance 14320. c.) variable inductance 14321. d.) piezoelectric effect 14322. 14323. (ECE Board Problem, November 2001) What do you call the telephone system connecting residence and business establishments? 14324. 14325. a.) Public Telephone System 14326. b.) Pay Phone System 14327. c.) Private Network System 14328. d.) Touch Tone System 14329. 14330. (ECE Board Problem, April 2000) In Broadcasting, an area characterized to have no interference but wit fading or intermittent variations in intensity is ______. 14331. 14332. a.) Primary Service Area 14333. b.) Intermediate Service Area 14334. c.) Tertiary Service Area 14335. d.) Secondary Service Area 14336. 14337. (ECE Board Problem, April 2002) Information capacity is proportional. 14338. 14339. a.) bandwidth 14340. b.) noise 14341. c.) power 14342. d.) flux 14343. 14344. (ECE Board Problem, April 2002) What is the number of lines per field in an NTSC TV? 14345. 14346. a.) 525 14347. b.) 262.5 14348. c.) 625 14349. d.) 312.5 14350. 14351. (ECE Board Problem, April 2002) It refers to the time required for a signal to complete one cycle. 14352. 14353. a.) Wavelength 14354. b.) Frequency 14355. c.) Amplitude 14356. d.) Period 14357. 14358. (ECE Board Problem, April 2002) What happens when the separation between two conductors having the same diameter decreases? 14359. 14360. a.) The characteristic impedance decreases. 14361. b.) The characteristic impedance increases, 14362. c.) The characteristic impedance does not change. 14363. d.) Cannot be determined 14364. 14365. (ECE Board Problem, November 2001) The government entity that regulates the cable television industry in the Philippines. 14366. 14367. a.) Executive Commission 14368. b.) House of Representatives 14369. c.) NTC 14370. d.) DOTC 14371. 14372. (ECE Board Problem, November 2001) A modulation which is amplitude modulated that consist of recurrent pulses. 14373. 14374. a.) PAM 14375. b.) PWM 14376. c.) PPM 14377. d.) AM 14378. 14379. (ECE Board Problem, November 2001) Which of the following consist of twp of the three primary colors in television signal? a.)red, b)violet,c)yellow, and d)blue. 14380. 14381. a.) a and b 14382. b.) b and c 14383. c.) c and d 14384. d.) a and d 14385. 14386. (ECE Board Problem, November 2001) Which of the navigational equipment which utilizes the principle of RADAR but is use in underwater? 14387. 14388. a.) TACAN 14389. b.) SONAR 14390. c.) TASI 14391. d.) RADAR 14392. 14393. (ECE Board Problem, November 2001) How can cross – modulation in a receiver be reduced? 14394. 14395. Adjust the pass band tuning. 14396. b.) Increase RF amplifier gain and decrease AF amplifier gain 14397. c.) Installing a filter at the receiver 14398. d.) Using a better antenna 14399. 14400. (ECE Board Problem, November 2001) The circuit that convert signal in order that it can be fed to the medium suitable for transmission. 14401. 14402. a.) Modulator 14403. b.) Mixer 14404. c.) Receiver 14405. d.) Transmitter 14406. 14407. (ECE Board Problem, November 2001) A type of Class C amplifier which has 1 to 10 times the gain of input used to generate frequency multiple of the fundamental frequency. 14408. 14409. a.) Frequency Generator 14410. b.) Frequency Multiplier 14411. c.) Frequency Amplifier 14412. d.) Frequency Divider 14413. 14414. (ECE Board Problem, November 2001) The definition of modulation index: 14415. 14416. a.) The radio of deviation frequency and modulating 14417. b.) The ratio of the maximum deviation frequency and maximum modulating frequency 14418. c.) The ratio of actual deviation to the maximum deviation 14419. d.) The ratio of the maximum deviation to the actual deviation 14420. 14421. (ECE Board Problem, November 2001) One of the following can be best attained by a trap antenna in radio communication? 14422. 14423. a.) Increase transmitter gain 14424. b.) Directionality 14425. c.) Effective filter to noise signal 14426. d.) Multi frequency band operation 14427. 14428. (ECE Board Problem, November 2000)when we talk of the study of acoustics, a sound is considered _____wave. 14429. 14430. a.) Circular 14431. b.) Light 14432. c.) Laser 14433. d.) Longitudinal 14434. 14435. (ECE Board Problem, November 1999) One of the major components required under the global maritime distress and safety system. 14436. 14437. a.) Provision of Morse code 14438. b.) Provision of radio telegraph operator 14439. c.) Provision of facsmile 14440. d.) Provision of radio personnel 14441. 14442. (ECE Board Problem, November 1999) A resultant effect in launching a satellite from the earth caused by both forward motion away from the earth that produces inertia tending the satellite to travel in straight line upwards and the gravitational pull towards the earth is referred to as ______. 14443. 14444. a.) Centripetal acceleration 14445. b.) Gravity 14446. c.) Weight of satellite 14447. d.) Satellite Speed 14448. 14449. (ECE Board Problem, April 2000) A RADAR set receiver has normally a ______mixer stage. 14450. 14451. a.) Tunnel diode 14452. b.) FET 14453. c.) Class A 14454. d.) Silicon Crystal 14455. 14456. (ECE Board Problem, April 1999) Refers to a connector that normally connects RG – 213 coaxial cable to an HF transceiver. 14457. 14458. a.) N-type Cable 14459. b.) F-type Cable 14460. c.) PL-259 14461. d.) BNC 14462. 14463. (ECE Board Problem, November 2000) Which of the following refers to the bandwidth of optical fiber? 14464. 14465. a.) 1 Hz-30,000 Hz 14466. b.) 1 kHz-300 kHz 14467. c.) 1MHz-300 MHz 14468. d.) 1MHz-500MHz 14469. 14470. (ECE Board Problem, April 1999) How many commissioners does the National Telecommunications Commission have? 14471. 14472. a.) 1 14473. b.) 5 14474. c.) 3 14475. d.) 2 14476. 14477. 14478. 14479. 14480. 14481. (ECE Board Problem, November 2000) Which one is referred to the reduction of receiver gain caused by strong signal from nearby transmission of adjacent frequency? 14482. 14483. a.) Intermodulation 14484. b.) Quieting 14485. c.) Fading 14486. d.) Desensitizing 14487. 14488. (ECE Board Problem, April 2000) Transmission of information through a communication modem is intended to transmit digital information over which of the following type of communication medium? 14489. 14490. Digital 14491. Hybrid 14492. Radio 14493. Analog 14494. 14495. (ECE Board Problem, April 1999) Determine from the following an advantage using a trap antenna. 14496. 14497. It has directivity in the high frequency bands. 14498. Can be used for multiband operation. 14499. Minimizes harmonic radiation. 14500. Has high gain. 14501. 14502. (ECE Board Problem, November 2002) What do you call a circuit in PCM wherein the instantaneous sinusoidal wave is regular sample and converted to a discrete amplitude levels? 14503. 14504. a.)analog to digital converter 14505. b.) sample and hold 14506. c.) modem 14507. d.) multiplexer 14508. 14509. (ECE Board Problem, April 1999) Determine from the following, possible cause for a slow drift of frequency in self-excited transmitter oscillator circuits resulting to poor frequency stability. 14510. 14511. a.)Faulty capacitors, resistors, tubes or transistors. 14512. b.) Loose shielding. 14513. c.) Heating in the oscillator device causing a change in electrical characteristics. 14514. d.) Loose connections in the oscillator, amplifier or antenna circuits. 14515. 14516. (ECE Board Problem, November 2000) Which of the following penalty is provided under the existing telecommunications law, should an international carrier unable to comply with its obligation to provide local exchange service in un-served and underserved areas within three years from grant of authority? 14517. 14518. a.)Financial penalty in accordance with existing schedules. 14519. b.)Cancellation of its authority. 14520. c.) Given one year to comply. 14521. d.) Given two years to comply. 14522. 14523. (ECE Board Problem, April 2000) In basic transmitter such as CW transmission, the rounding off of square wave emission will reduce______. 14524. 14525. Reach 14526. Voltage 14527. Bandwidth 14528. Transmitter power 14529. 14530. (ECE Board Problem, November 1999) Refers to one possible cause for an abrupt frequency variation in a self-excited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant oscillation. 14531. 14532. Poor soldered connections. 14533. Heating of capacitor in the oscillator. 14534. DC and RF ac heating of resistors, which cause change in values. 14535. Aging which cause change condition in parts characteristics. 14536. 14537. 14538. (ECE Board Problem, November 2000)which of the following is referred to the SYN character of ASCII code? 14539. 14540. a.)32H 14541. b.)16H 14542. c.)64H 14543. d.)8H 14544. 14545. (ECE Board Problem, November 1999)In a basic radio transmitter, what is the main disadvantage of a single-tube transmitter? 14546. 14547. a.)Frequency Instability 14548. b.)Non-portable 14549. c.)Heating Effect 14550. d.)Bulky 14551. 14552. (ECE Board Problem, April 2000) One of the following is considered the largest source of signal power loss in the use of fiber optic as a communication medium such as due to misalignment. 14553. 14554. a.) Bending 14555. b.) Scattering 14556. c.) Connection 14557. d.) Absorption 14558. 14559. (ECE Board Problem, November 2000) Statement, which best describe a mixing process in radio communication. 14560. 14561. a.) Process of eliminating noise through phase differentiation. 14562. b.) Producing sum and difference of two frequencies from a combination of two signals. 14563. c.) Processing of eliminating noise through phase comparison. 14564. d.) Combination of two signals to form three or more output signals. 14565. 14566. (ECE Board Problem, November 2001)What is the input impedance equivalent of an open-ended transmission line which is longer than a quarter wavelength? 14567. 14568. a.) Open equivalent 14569. b.) Equivalent to reactive circuit 14570. c.) As resistive equivalent 14571. d.) As pure inductor 14572. 14573. (ECE Board Problem, November 2000) How would you isolate data communications faults in a basic error determination technique? 14574. 14575. a.) Test each cards. 14576. b.) Simulate the loop. 14577. c.) Test each repeater. 14578. d.) Carry out loopback test. 14579. 14580. (ECE Board Problem, April 2000) Which of the following describes its system services control point, logical units and physical units as network addressable units in a data network? 14581. 14582. a.) Digital Network Architecture 14583. b.) Internetworking 14584. c.) Interconnection Point 14585. d.) System Network Architecture 14586. 14587. (ECE Board Problem, November 2000) A telecommunications law that deregulates the paging services in the country. 14588. 14589. a.) E. O. 125 14590. b.) Act 3846 14591. c.) Act 3396 14592. d.) R.A. 7925 14593. 14594. 14595. (ECE Board Problem, April 2000) What refers to breaking up the data into blocks with some bounded size? 14596. 14597. a.) Framing 14598. b.) Segmentation 14599. c.) Encapsulation 14600. d.) Packing 14601. 14602. (ECE Board Problem, November 2001) What is the apogee of a geosynchronous satellite’s temporary orbit before be placed in the geosynchronous orbit? 14603. 14604. a.) 50,000 mi 14605. b.) 40,000 mi 14606. c.) 22,300 mi 14607. d.) 30,000 mi 14608. 14609. (ECE Board Problem, November 2001) A device used in television broadcast that prevents any FM signal from entering into the visual transmitter and vice versa. 14610. 14611. a.) Duplexer 14612. b.) Mixer 14613. c.) Diplexer 14614. d.) Synchronizer 14615. 14616. (ECE Board Problem, November 1999) A sound intensity that could cause painful sensation in the human ear. 14617. 14618. a.) Threshold of Sense 14619. b.) Threshold of Pain 14620. c.) Hearing Threshold 14621. d.) Sensation Intensity 14622. 14623. (ECE Board Problem, April 1999) What is the first symbol of radio signal emission having an amplitude modulated main carrier single sideband suppressed carrier? 14624. 14625. a.) C 14626. b.) A 14627. c.) J 14628. d.) H 14629. 14630. (ECE Board Problem, November 1999) What us the baseband frequency of standard FDM basic super group? 14631. 14632. 300 to 600 kHz 14633. 312 to 552 kHz 14634. 60 to 2540 kHz 14635. 60 to 180 kHz 14636. 14637. (ECE Board Problem, November 1999) Very High (radio) Frequency in the spectrum refers to ______waves. 14638. 14639. Centimetric 14640. Hectometric 14641. Kilometric 14642. Metric 14643. 14644. 100. (ECE Board Problem, April 1999) What wave trap frequency is used in the video amplifier? 14645. 14646. 39.75 MHz 14647. 41.25 MHz 14648. 4.5 MHz 14649. 47.25 MHz 14650. 14651. 101.(ECE Board Problem, November 2000) Which of the following best described the primary source of errors in the transmission of data over telephone networks? 14652. 14653. Thermal Noise 14654. Crosstalk 14655. Impulse Noise 14656. Intermodulation 14657. 14658. 14659. 102. (ECE Board Problem, April 1999) Which part of the HF marine antenna handles the broken safety link, in case it results collision, grounding or storm? 14660. 14661. The lead-in. 14662. The foremast. 14663. The strong part. 14664. The halyard. 14665. 14666. 103. (ECE Board Problem, April 2000) A reduction in receiver sensitivity caused by unwanted high-level adjacent channel signals. 14667. 14668. Intermodulation 14669. Overloading 14670. Interference 14671. Desensitizing 14672. 14673. 14674. 14675. 14676. 104. (ECE Board Problem, November 2000) Which of the following system uses frequency band 870-890 MHz as a transmit band of its base station? 14677. 14678. Total Access Communication System (TACS) 14679. Nordic Mobile Telephone (NMT) 14680. Public Mobile System (PMS) 14681. Advance Mobile Phone Services (AMPS) 14682. 14683. 105. (ECE Board Problem, November 2000) Refers to a mobile earth station in the mobile-satellite service located on board ship. 14684. 14685. Mobile Station 14686. Ship Station 14687. Ship Earth Station 14688. Mobile Satellite Station 14689. 14690. 106. (ECE Board Problem, November 2002) What is the electric field strength in millivolts per meter if the transmitted power is 30kW, at a distance of 5km? 14691. 14692. 120 mV/m 14693. 190 mV/m 14694. 150 mV/m 14695. 30 mV/m 14696. 14697. 107. (ECE Board Problem, November 2000) Frequency band where Total Access Communication System is allocated. 14698. 14699. 86-869 MHz; 821-824 MHz 14700. 870-890 MHz; 825-845 MHz 14701. 851-866 MHz; 806-821 MHz 14702. 935-960 MHz; 890-915 MHz 14703. 14704. 108. (ECE Board Problem, November 2000) Which of the following is used as a standard channel spacing for AM broadcast in the Philippines? 14705. 14706. 25 kHz 14707. 12.5 kHz 14708. 40 kHz 14709. 9 kHz 14710. 14711. 109. (ECE Board Problem, November 2000) What is the frequency separation between the aural carrier and the lower limits of the total channel band of a monochrome TV broadcast? 14712. 14713. 1.25 MHz 14714. 4.5 MHz 14715. 3.0 MHz 14716. 5.75 MHz 14717. 14718. 110. (ECE Board Problem, November 2000) Which salellite transponder has the most number of mixers? 14719. 14720. Regenerative 14721. Broadband 14722. Double-Conversion 14723. Channelized 14724. 14725. 111. (ECE Board Problem, November 2000) An advantage of fiber optic co-axial cable as a result of coupling signals from one to the other due to changing magnetic field in one or both. 14726. 14727. Feedback 14728. Crosstalk 14729. Electric Hazard 14730. Shielding 14731. 14732. 112. (ECE Board Problem, April 2001) How can even-order harmonics be reduced or prevented in transmitter amplifier design? 14733. 14734. By using a push-push amplifier 14735. By using push-pull amplifier 14736. By operating Class C 14737. By operating Class AB 14738. 14739. 113. (ECE Board Problem, April 2002) With which emission type is the capture effect most pronounced? 14740. 14741. FM 14742. SSB 14743. AM 14744. CW 14745. 14746. 114. (ECE Board Problem, April 2002)What is the term used to refer to the reception blockage of one FM-phone signal by another FM-phone signal? 14747. 14748. Desensitization 14749. Cross-modulation Interference 14750. Capture Effect 14751. Frequency Discrimination 14752. 14753. 115. (ECE Board Problem, April 2002) What is the primary purpose of an RF amplifier in a receiver? 14754. 14755. To provide most of the receiver gain. 14756. To develop the AGC voltage. 14757. To improve the receiver’s noise figure. 14758. To vary\ the receiver image rejection by utilizing the AGC. 14759. 14760. 116. (ECE Board Problem, April 2002)What is the product of the power fed to the antenna and its power gain? 14761. 14762. Antenna Power 14763. ERP 14764. PEP 14765. Peak Power 14766. 14767. 117. (ECE Board Problem, April 1999) What is the reason why Hertz antenna is not normally used to radio station or receiver or transmitter antenna that has frequency below 2MHz? 14768. 14769. The antenna receives more inter-modulation signal. 14770. The antenna receive side becomes non-receptive. 14771. The antenna will be physically very small. 14772. The antenna will be physically very large. 14773. 14774. 118. (ECE Board Problem, November 1999) In the study of transmission cable, twin lead is also referred to as______. 14775. 14776. Twisted pair 14777. Double cable 14778. Ribbon cable 14779. Open pair 14780. 14781. 119. (ECE Board Problem, November 1999) In an open architecture concept of data communication, one of the following is not a function of a control layer. 14782. 14783. Fault correction 14784. Congestion control 14785. Fault detection 14786. Integrity of data 14787. 14788. 120. (ECE Board Problem, November 1999)What are the two legislative function of the International Telecommunications Union in its international conference issues on orbital resources? 14789. 14790. Assign frequencies and organizes conferences. 14791. Allocates frequency bands for the services and determine the principle of distribution of orbit/spectrum resources. 14792. Determine the principles of spectrum distribution and assignment of frequencies. 14793. Conduct conferences and allocation of orbital slot. 14794. 14795. 121. (ECE Board Problem, April 2002)What transmission medium is capable of carrying up to 10Gbps capacity? 14796. 14797. Twisted pair 14798. Optical fiber 14799. Coax 14800. Microwave link 14801. 14802. 122. (ECE Board Problem, April 2002) What is the controlling node of a star topology system? 14803. 14804. Modem 14805. Codec 14806. Hub 14807. ADC 14808. 14809. 123. (ECE Board Problem, April 2002) What is the most efficient topology used by small business organization? 14810. 14811. Mesh 14812. Star 14813. Bus 14814. Ring 14815. 14816. 124. (ECE Board Problem, April 2002)Which of the following network topology has the fastest speed? 14817. 14818. Star 14819. Ring 14820. Bus 14821. Mesh 14822. 14823. 125. (ECE Board Problem, April 2002) The latest and most advanced equipment in data communications is a/an______. 14824. 14825. Amplifier 14826. Simulator 14827. Protocol analyzer 14828. Spectrum analyzer 14829. 14830. 126. (ECE Board Problem, April 2002) Which has the highest priority in radio telephone communication? 14831. 14832. Distress 14833. Safety 14834. Urgency 14835. Roger 14836. 14837. 127. (ECE Board Problem, April 2002) In satellite communications, what is the frequency of the V-band? 14838. 14839. 27-40 GHz 14840. 4-8 GHz 14841. 8-12GHz 14842. 40-75 GHz 14843. 14844. 128. (ECE Board Problem, April 2002) What is meant by the term antenna gain? 14845. 14846. The numerical ratio relating the radiated signal strength of an antenna to that of another antenna. 14847. The ratio of the signal in the forward direction to the signal in the back direction. 14848. The ratio of the amount of power to produce by the antenna compared to the output power of the transmitter. 14849. The final amplifier gain minus the transmission line losses. 14850. 14851. 129. (ECE Board Problem, April 2002) What is an advantage using a trap antenna? 14852. 14853. It has antenna gain 14854. It minimizes harmonic radiation 14855. It has high directivity in the high frequency bands 14856. It may be used for multiband operations 14857. 14858. 130. (ECE Board Problem, April 2002) What is the wavelength of a shorted stub used to absorb even harmonics? 14859. 14860. 0.5 wavelength 14861. 1/3 wavelength 14862. 0.25 wavelength 14863. 1/8 wavelength 14864. 14865. 131. (ECE Board Problem, November 2002) Who coined the term fiber optics? 14866. 14867. Hansell 14868. Hopkins 14869. N.S. Kapany 14870. Van heel 14871. 14872. 132. (ECE Board Problem, April 2002) How does the length of the reflector element of a parasitic beam antenna compare with that of a driven element? 14873. 14874. It is about 5% longer. 14875. It is about 5% shorter 14876. It is twice as long 14877. It is one-half as long 14878. 14879. 133. (ECE Board Problem, April 2001) In a half wave antenna, where are the current nodes? 14880. 14881. At the ends 14882. At the center 14883. One-half of the way from the feed point toward the end. 14884. Three-quarters of the way from the feed point toward the end. 14885. 14886. 134. (ECE Board Problem, April 2002) Why is a loading coil often used with an HF mobile antenna? 14887. 14888. To improve reception 14889. To lower the losses 14890. To lower the Q. 14891. To tune out the capacitive resistance. 14892. 14893. 135. (ECE Board Problem, April 2002) What is a frequency discriminator? 14894. 14895. A circuit for detecting FM signals 14896. A circuit for filtering two closely adjacent signals. 14897. An automatic band switching circuit. 14898. An FM generator. 14899. 14900. 136. (ECE Board Problem, April 2002) What is the period of a wave? 14901. 14902. The time required to complete one cycle. 14903. The number of degrees in one cycle. 14904. The number of zero crossing in one cycle. 14905. The amplitude of the wave. 14906. 14907. 137. (ECE Board Problem, April 2002) The implementing guidelines on international satellite communications is______. 14908. 14909. EO 467 14910. EO 846 14911. DO 11 14912. DO 88 14913. 14914. 138. (ECE Board Problem, April 2002) What was implemented in 1999 which has the purpose of aiding the maritime navigation using satellite as well as advanced terrestrial communication system? 14915. 14916. GMDSS 14917. AMPS 14918. GLONASS 14919. NAVSTAR 14920. 14921. 139. (ECE Board Problem, April 2002) Which of the following is not a DTE? 14922. 14923. Telephone set 14924. Computer 14925. Bridge 14926. Printer 14927. 14928. 140. (ECE Board Problem, April 2002)What is the transmission of data through a different time slots? 14929. 14930. TDM 14931. FDM 14932. WDM 14933. CDM 14934. 14935. 141. (ECE Board Problem, April 2002) What is the parameter that affects the computation of image frequency? 14936. 14937. Q 14938. fLO 14939. fIF 14940. D 14941. 14942. 142. (ECE Board Problem, April 2002) Which of the following could not be observed in a microwave communications? 14943. 14944. LOS 14945. Wide BW 14946. Better Signal Penetration 14947. Directional Antenna 14948. 14949. 14950. 143. (ECE Board Problem, April 2002) The service area where the signal is subject to fading with no objectionable interference. 14951. 14952. Primary service area 14953. Secondary service area 14954. Intermittent service area 14955. Quarternary service area 14956. 14957. 144. (ECE Board Problem, April 2002) By examining the following antenna type, determine which is properly terminated? 14958. 14959. Non-resonant Type 14960. Half-wave Dipole 14961. Whip antenna Type 14962. Resonant Type 14963. 14964. 145. (ECE Board Problem, April 2001) What is the third letter symbol in the emission designation for telemetry? 14965. 14966. F 14967. B 14968. D 14969. N 14970. 14971. 146. (ECE Board Problem, April 2002) What is the frequency tolerance of FM broadcasting? 14972. 14973. 25 kHz 14974. 20 kHz 14975. 2 kHz 14976. 30 kHz 14977. 14978. 147. (ECE Board Problem, April 2001) Which of the following is commonly used search engine? 14979. 14980. .edu 14981. www 14982. .org 14983. Excite 14984. 14985. 148. (ECE Board Problem, April 2001)When the electric field is perpendicular to the surface of the earth, what is the polarization of the electromagnetic wave? 14986. 14987. Vertical 14988. Horizontal 14989. Circular 14990. Elliptical 14991. 14992. 149. (ECE Board Problem, April 2001) What is the deviation ratio of an FM signal if the maximum allowable deviation is 12 kHz and the maximum intelligence frequency is 4 kHz? 14993. 14994. 3 14995. 48 14996. 2/3 14997. 1/3 14998. 14999. 150. (ECE Board Problem, April 2002) What is the typical satellite communications bandwidth? 15000. 15001. 20 MHz 15002. 30 MHz 15003. 40 MHz 15004. 500 MHz 15005. 15006. 151. (ECE Board Problem, April 2001) the following are not used in radio communications, except______. 15007. 15008. Infrared 15009. Cosmic 15010. X-ray 15011. Gamma 15012. 15013. 152. (ECE Board Problem, April 2001) A modem which can be used to send data and fax. 15014. 15015. Bell 212A 15016. ARQ 15017. Fax modem 15018. Data modem 15019. 15020. 153. (ECE Board Problem, April 2001) What is the output of a balanced modulator. 15021. 15022. SSB 15023. DSB 15024. ISB 15025. VSB 15026. 15027. 154. (ECE Board Problem, April 2002) An emission technique where the total current will be twice as much when the modulation index is doubled. 15028. 15029. J3E 15030. H3E 15031. A3E 15032. R3E 15033. 155. (ECE Board Problem, April 2001) Which of the following uses frequency modulator circuit? 15034. 15035. A3E 15036. F3E 15037. H3E 15038. R3E 15039. 15040. 156. (ECE Board Problem, April 2002) What is used to display harmonics and fundamental frequency? 15041. 15042. Oscilloscope 15043. Spectrum Analyzer 15044. Wattmeter 15045. Ohmmeter 15046. 15047. 157. (ECE Board Problem, November 2002) What is the free space loss, in dB, of a microwave system when the frequency is 6 GHz at 40km apart? 15048. 15049. 170 dB 15050. 150 dB 15051. 160 dB 15052. 140 dB 15053. 15054. 158. (ECE Board Problem, April 2001) When the signal becomes weak, the base will request the MTSO to find another site. 15055. 15056. Roaming 15057. Hand-off 15058. Frequency Re-use 15059. Cell splitting 15060. 15061. 159. (ECE Board Problem, April 2001) What is the interference between the switching office and the mobile unit. 15062. 15063. Cell sites 15064. MTSO 15065. Microwave link 15066. Base station 15067. 15068. 160. (ECE Board Problem, April 2001) Which is not an omni-directional antenna? 15069. 15070. Vertical folded dipole 15071. Discone 15072. Rhombic 15073. Marconi 15074. 15075. 161. (ECE Board Problem, April 2001) Which satellite band is affected by VHF signals? 15076. 15077. L 15078. C 15079. P 15080. Ku 15081. 15082. 162. (ECE Board Problem, April 2001) What is produced by over-modulation in AM? 15083. 15084. Sidebands 15085. Jitter 15086. Glitch 15087. Spurious Signal 15088. 15089. 163. (ECE Board Problem, April 2001)_____ is the process of sending out the information in all directions. 15090. 15091. Navigation 15092. Broadcasting 15093. Acoustics 15094. Telemetry 15095. 15096. 164. (ECE Board Problem, April 2001) How do you increase the electrical length of an antenna? 15097. 15098. Add an inductor in parallel 15099. Add an inductor in series 15100. Add a capacitor in series 15101. Add a resistor in series. 15102. 15103. 165. (ECE Board Problem, April 2001) What is the usual electrical length of a driven element in HF beam antenna? 15104. 15105. ¼ wavelength 15106. ½ wavelength 15107. ¾ wavelength 15108. 1 wavelength 15109. 15110. 166. (ECE Board Problem, April 2002) What is the point in the satellite as it crosses the equator? 15111. 15112. Apogee 15113. Node 15114. Perigee 15115. Orbit 15116. 15117. 167. (ECE Board Problem, November 2001) Direct Distance Dialing is______. 15118. 15119. Private line 15120. Public line 15121. Lease line 15122. Dial-up 15123. 168. (ECE Board Problem, November 2001)A path wherein a satellite crosses in the equator heading south. 15124. 15125. Ascending node 15126. Descending node 15127. Orbital 15128. Polar 15129. 15130. 169. (ECE Board Problem, November 2001) In what frequency band does 4-6 GHz fall in the satellite communications? 15131. 15132. C-Band 15133. L-Band 15134. X-band 15135. K-band 15136. 15137. 170. (ECE Board Problem, November 2001) A computer network found in the same building. 15138. 15139. Local area network 15140. Wide area network 15141. Metropolitan area network 15142. PLL 15143. 15144. 171. (ECE Board Problem, April 2002) Which of the following antenna feedline can easily be buried underground for a distance without adverse effects? 15145. 15146. Waveguide 15147. Twisted pair 15148. Coaxial cable 15149. Twin lead 15150. 15151. 172. (ECE Board Problem, April 1999) In the study of wave propagation, a condition at which zero absorption of radio waves is describe as______. 15152. 15153. Zero reflection medium 15154. Neutral medium 15155. Free space medium 15156. Non-active medium 15157. 15158. 173. (ECE Board Problem, November 1999) Which of the following in the radio emission designation refers to the first symbol? 15159. 15160. Nature of signal modulating the main carrier 15161. Type of modulation of the main carrier 15162. Emission bandwidth 15163. Type of information 15164. 15165. 174. (ECE Board Problem, November 2000) The process of exchanging predetermine codes and signals in telecommunications between two data terminals to establish a connection is called. 15166. 15167. Hands-off 15168. Polling 15169. Handshake 15170. Demodulation 15171. 15172. 175. (ECE Board Problem, April 2000) It is an electronic instrument which can be referred to as a miniature radio transmitter and can be made to generate signals at any desired frequency, normally it is used for test purposes. 15173. 15174. Volt-ohm milliammeter 15175. Signal generator 15176. Oscilloscope 15177. Wavemeter 15178. 15179. 176. (ECE Board Problem, April 1999) A network interconnection facility which is used to interconnect networks whose architectures are entirely different is called______. 15180. 15181. Bridge 15182. Router 15183. Gateway 15184. Repeater 15185. 15186. 177. (ECE Board Problem, November 1999) Type of multi-channel transmission in the optic fiber communication that uses a twisted pair coupler to transmit two signals of different wavelengths. 15187. 15188. Frequency-division multiplexing 15189. Forward-division multiplexing 15190. Pulse-code multiplexing 15191. Time-division multiplexing 15192. 15193. 15194. 15195. 15196. 178. (ECE Board Problem, April 2000) These are the rules in data communications intended for establishing data links and message interpretation. 15197. 15198. Mode 15199. EIA Rules 15200. CCIR Rules 15201. Protocol 15202. 15203. 179. (ECE Board Problem, November 1999) A radio station in mobile service intended to be used while in motion or during halts at unspecified points. 15204. 15205. Maritime radio station 15206. Land mobile station 15207. Mobile station 15208. Mobile earth station 15209. 15210. 180. (ECE Board Problem, April 1999) What is the advantage on the TV receiver audio by employing FM audio and AM video on the television transmitter? 15211. 15212. FM receiver rejects static noise 15213. FM receiver is basically insensitive to amplitude modulation 15214. Fm receiver is basically insensitive to amplitude modulation 15215. FM receiver is clear over AM. 15216. 15217. 181. (ECE Board Problem, April 1999) What does the elastic store refereed to in the time division multiplex system used in fiber optic? 15218. 15219. Amplifier 15220. Holding memory 15221. Reflector 15222. Timer 15223. 15224. 182. (ECE Board Problem, November 1999) What are the two general categories of methods for generating emission F3E? 15225. 15226. The only way to produce an emission F3E signal is with a reactance modulator on the oscillator. 15227. The only way to produce an emission F3E signal is with a balanced modulator on the oscillator. 15228. The only way to produce an emission F3E signal is with a balanced modulator on the audio amplifier. 15229. The only way to produce an emission F3E signal is with a reactance modulator on the final amplifier. 15230. 15231. 15232. 15233. 183. (ECE Board Problem, November 2002) Pressure us measured in terms of Pascal, microbar, or______. 15234. 15235. Newtons 15236. Newtons per meter 15237. Newtons per meter squared 15238. Pascal per meter squared 15239. 15240. 184. (ECE Board Problem, April 1999) What is the function of the network layer in the computer communications? 15241. 15242. Parity control 15243. Direction control 15244. Congestion control 15245. Error control 15246. 15247. 185. (ECE Board Problem, April 2000) Which of the following limits the top speed of transmitting information in fiber optic? 15248. 15249. Noise 15250. Detector speed 15251. Time domain 15252. Refractor index 15253. 15254. 186. (ECE Board Problem, April 1999) A mobile telephone system which uses an analogue cellular radio standard which was superseded by Advanced Mobile Phone System in the U.S. 15255. 15256. TDMA 15257. IMTS 15258. CDMA 15259. D-AMPS 15260. 15261. 187. (ECE Board Problem, November 2000) Satellite that rotates around the earth in a low altitude elliptical or circular pattern. 15262. 15263. Geosynchronous Satellite 15264. Prograde 15265. Nonsynchronous satellite 15266. Apogee 15267. 15268. 188. (ECE Board Problem, April 2000) One of the following processes or system best describe an example of a pilot tone system normally use in commercial broadcast FM stations. 15269. 15270. Time division 15271. Frequency division 15272. Stereo multiplex 15273. QSK 15274. 15275. 189. (ECE Board Problem, November 2000) What is the main reason why coaxial cable is not used in microwave signal transmission? 15276. 15277. Wide bandwidth 15278. Number of repeaters 15279. Low impedance 15280. High attenuation 15281. 15282. 190. (ECE Board Problem, April 2000) Refers to a characteristic of a multimode fiber optic. 15283. 15284. Cladding thickness is less than the radius of the core and diameter of the core must be greater than the wavelength of the light to be carried. 15285. Cladding thickness is greater than the radius of the core and the diameter of the core must be lesser than the wavelength of the light to be carried. 15286. Cladding thickness is less than the radius of the core and the diameter of the core must be lesser than the wavelength of the light to be carried. 15287. Cladding thickness is greater than the radius of the core and the diameter of the core must be much greater than the wavelength of the light to be carried. 15288. 191. (ECE Board Problem, April 2000) Two or more LAN linked together over the wide geographical area. 15289. 15290. HAN 15291. WAN 15292. MAN 15293. RAN 15294. 15295. 192. (ECE Board Problem, April 2000) A process of sending data in computing technology by asking each remote computer terminal one at a time if such computer terminal has data to send. 15296. 15297. Selection 15298. Networking 15299. Polling 15300. Coding 15301. 15302. 193. (ECE Board Problem, November 1999) What is the primary purpose of an RF amplifier in receiver? 15303. 15304. To vary the receiver image rejection by utilizing the AGC. 15305. To provide the most receiver gain. 15306. To develop the AGC voltage. 15307. To improve the receiver’s noise figure. 15308. 15309. 194. (ECE Board Problem, April 2000) Why are fiber optic cables considered less expensive compared to coaxial cables in communication system? 15310. 15311. Coaxial is very expensive than fiber optic. 15312. Due to weight. 15313. Installation cost of coaxial. 15314. Use of less repeaters. 15315. 15316. 195. (ECE Board Problem, November 1999) Refers to as a linkage by wire, radio, satellite or other means, of two or more telecommunications carrier or operators with one another for the purpose of allowing or enabling the subscriber of one carrier or operator to access or reach the subscribers of the other carrier or operator. 15317. 15318. Interconnection 15319. Toll patching 15320. Gateway 15321. Outside plant sharing 15322. 196. (ECE Board Problem, November 1999) In order to have an effective radio antenna the design of its radiator must have a minimum length equivalent to______. 15323. 15324. Λ/10 15325. Λ/4 15326. Λ/14 15327. Λ/6 15328. 15329. 197. (ECE Board Problem, April 2000) Referred as the forward link channel of the cellular duplex system. 15330. 15331. Cell to Cell 15332. Mobile to Mobile unit 15333. Mobile to Cell unit 15334. Cell to Mobile unit 15335. 15336. 198. (ECE Board Problem, November 2000) Method of a telecommunications operation where transmission can be made simultaneously in both direction of a channel. 15337. 15338. Semi-duplex Operation 15339. Duplex Operation 15340. Half-duplex Operation 15341. Simplex Operation 15342. 15343. 15344. 199. (ECE Board Problem, April 2000) Which symbol in radio signal emission designation is referred to type of modulation of the main carrier? 15345. 15346. Second 15347. Fourth 15348. Third 15349. First 15350. 15351. 200. (ECE Board Problem, November 2000) What type of emission is produced when an amplitude-modulated transmitter is modulated by a facsimile signal? A3F F3 A3C F3F 15352. 201. (ECE Board Problem, November 2000) A point in the satellite orbit known to be the closest location to the surface of the earth. Zenith Perigee Apogee Azimuth

15353. 202. (ECE Board Problem, November 2000) Determine from the following the common use of DSB in broadcast and telecommunication.

15354. Satellite Communication

15355. FM/TV Stereo

15356. Two-Way Communication

15357. Telephone System

15358. 203. (ECE Board Problem, November 2000) Determine the image frequency of a broadcast band receiver using a 455 kHz IF tuned to 630kHz-DZMM.

15359. 1085 kHz

15360. 1530 kHz

15361. 1540 kHz

15362. 1715 kHz

15363.

15364.

15365.

15366. 204. (ECE Board Problem, November 2000) A phenomenon which causes the speed of light rays propagation in the fiber material changes, as it passes through different medium in the fiber.

15367. Bending

15368. Refraction

15369. Diffraction

15370. Reflection 15371. 205. (ECE Board Problem, November 1999) An electronic equipment used in the radio communication to measure standing wave ratio.

15372. Radio meter

15373. Reflectometer

15374. Oscilloscope

15375. Wave Meter

15376.

15377. 206. (ECE Board Problem, November 2000) Referred as an effect of parasitic elements in an antenna system.

Decrease its directivity

Makes the antenna omni directional

Makes the antenna isotropic

Increase its directivity

15378. 207. (ECE Board Problem, November 2000) Radio wave concentration in the direction of the signal emitted by a directional antenna.

15379. Side lobe radiation

15380. Major lobe radiation

15381. Back lobe radiation

15382. Transmitted signal

15383.

15384. 208. (ECE Board Problem, November 2002) What is the main principle used by ITU in determining the distribution of the orbit/ spectrum resources?

15385. Depending on the geographical boundary of a nation

15386. Efficient use and equitable access.

15387. Depending on a national sovereignty declaration

15388. Equal distribution

15389. 15390.

15391. 209. (ECE Board Problem, April 2000) What quarter-wave transformer will match a 600Ω transmission line to an antenna whose value is 70 Ω?

15392. 205 Ω

15393. 502 Ω

15394. 600 Ω

15395. 75 Ω

15396. 210. (ECE Board Problem, November 1999) Let us consider a frequency range of 405.0125 MHz to 405.0875 MHz and a 25 kHz channeling plan, determine the center frequency of the second channel from the lower limit.

15397. 405.050 MHz

15398. 405.0125 MHz

15399. 405.025 MHz

15400. 405.011 MHz

15401. 211. (ECE Board Problem, April 2000) What is the reason why 5/8-whip vertical antenna is of advantage than quarter wave vertical whip antenna?

15402. Less interference

15403. Can handle high power signal

15404. More gain

15405. Flexible

15406. 212. (ECE Board Problem, April 1999) Why is it that almost all switching type integrated data communication circuits are called digital?

15407. They are mostly on/off devices.

15408. They process digital information

15409. They are small type

15410. They are integrated circuits.

15411. 213. (ECE Board Problem, November 2000)Which of the following shall be complied by an international ship pursuant to the global maritime distress and safety system implemented last 1999?

15412. A facsimile

15413. A radio personnel

15414. A Morse code

15415. A radio telegraph operator

15416.

15417.

15418.

15419. 214. (ECE Board Problem, November 2000) Bit rate of a telecommunications carrier T2.

15420. 7.312 Mb/s

15421. 7.318 Mb/s

15422. 6.511 Mb/s

15423. 6.312 Mb/s

15424. 215. (ECE Board Problem, November 2000) In propagation of radio signals through an aerial at what angle does not magnetic field is positioned with reference to the direction of propagation.

15425. 180

15426. 90

15427. 0

15428. 45

15429. 216. (ECE Board Problem, April 1999) What is the frequency separation between the visual carrier and the upper limits of its total channel bandwidth of a monochrome TV broadcast?

15430. 4.5 MHz

15431. 4.75 MHz

15432. 3.0 MHz 15433. 1.25 MHz

15434. 217. (ECE Board Problem, November 2000) In radio communications, the term trap antenna is referred to in one of the following statements.

15435. Antenna with wide beam width

15436. Those antennas with high rejecting capability to interfering signals.

15437. Those antenna with long coverage in terms of distance

15438. Antenna which can be used on more than one band due to the use of parallel LC networks.

15439. 218. (ECE Board Problem, April 1999) What is the range of an AM broadcast frequency tolerance above or below its assigned frequency?

15440. 25kHz

15441. 20 Hz

15442. 60 kHz

15443. 120 kHz

15444. 219. (ECE Board Problem, April 2000) Which part of the housing system in ECE code is a circular opening through the floor structure to allow the passage of cable and wire.

15445. Insert

15446. Sleeve

15447. Raceway

15448. Slot

15449. 220. (ECE Board Problem, April 2000) What is the length of a simple quarter wave antenna using a VHF frequency of 150.55 MHz?

15450. 0.98 ft.

15451. 1.24 ft.

15452. 1.80 ft.

15453. 1.55 ft.

15454. 221. (ECE Board Problem, November 2000) In the study of acoustics, the velocity of sound is dependent to one of the following. 15455. Temperature

15456. Loudness

15457. Source of sound

15458. Properties of the medium

15459. 222. (ECE Board Problem, April 1999) Which of the following is not considered as one of the causes for the loss of signal power as light travels through a fiber optic?

15460. Scattering

15461. Intermodulation

15462. Fiber bending

15463. Absorption

15464. 223. (ECE Board Problem, November 1999) Referred to as a light source of fiber optic, which supplies power level of 5 to 7 mW and having a narrow spectrum of emission.

15465. Injection laser diode

15466. Photodiode

15467. Light emitting diode

15468. Crystal diode

15469. 224. (ECE Board Problem, April 2000) A digital mobile telephone system, which is called European derivative of Global System for Mobile Communication System operating at a higher frequency band.

15470. E-TACS

15471. IMTS

15472. DCS-1800

15473. TACS

15474. 225. (ECE Board Problem, April 1999) Communication through the use of a modem is transmission of______data information in ______medium.

15475. Analog, analog

15476. Analog, digital 15477. Digital, analog

15478. Digital, digital

15479. 226. (ECE Board Problem, November 1999) What type of emission is produced when amplitude modulated transmitter is modulated by a television signal?

15480. A3F

15481. F3C

15482. F3F

15483. A3C

15484.

15485. 227. (ECE Board Problem, April 1999) A term, used in radio communication defining the frequency band from the lowest to its highest limits, designed to be passed through a component, system or a device with an acceptable attenuation.

15486. Allocated band

15487. Baseband

15488. Bandwidth

15489. Transmitted signal

15490. 228. (ECE Board Problem, April 2000) Which body in the present ITU structure took the place of CCITT?

15491. ITU-R

15492. ITU-D

15493. ITU-T

15494. RAG

15495.

15496. 229. (ECE Board Problem, November 2002) What is the frequency range of VLF?

15497. 10-10 kHz

15498. 30-300 kHz 15499. 300-3000 kHz

15500. 3-30 kHz

15501. 230. (ECE Board Problem, April 1999) What is a wave front?

15502. A voltage pulse in a conductor

15503. A current pulse in the conductor

15504. A voltage pulse across a resistor

15505. A fixed point in an electromagnetic wave

15506. 231. (ECE Board Problem, November 2000) How would you best describe an example of a pilot tone system use in commercial frequency modulation broadcast radio stations?

15507. Frequency simplex

15508. Time division

15509. Stereo multiplex

15510. QSK

15511.

15512. 232. (ECE Board Problem, April 1999) Kind of broadcasting system where television programs are transmitted directly to home/user receivers via satellite, thus making the reception cover not only individuals in their homes but other places as well.

15513. Pay TV

15514. Direct to Home TV

15515. Cable TV

15516. VHF TV

15517. 233. (ECE Board Problem, November 1999) In telecommunication, what do we call the difference in the voltage level between a driver and a terminator?

15518. System gain

15519. Noise margin

15520. System loss 15521. Noise difference

15522. 234. (ECE Board Problem, April 2000) Why is parallel transfer method in data transmission faster then serial?

15523. Wider channel bandwidth

15524. Bits are transferred simultaneously

15525. Bits are lighter in parallel

15526. Due to faster changes in symbol

15527. 235. (ECE Board Problem, November 2000) Radio frequency where waveguide is not used extensively.

15528. 3,750 MHz

15529. 2,000 MHz

15530. 10,300 MHz

15531. 150 MHz

15532. 236. (ECE Board Problem, April 1999) One of the following central office switching equipment resistance limit refers to the longest subscriber loop length.

15533. 1500Ω

15534. 300Ω

15535. 2000Ω

15536. 800Ω

15537. 237. (ECE Board Problem, November 1999) A particular area on the surface of the earth where the boresight of a steerable satellite beam is intended to be pointed.

15538. Footprint area

15539. Contour boresight area

15540. Equivalent service area

15541. Effective boresight area

15542. 238. (ECE Board Problem, April 1999) Kind of information transfer in digital communication where the bits comprising one character are sent in sequence one at a time. 15543. Parallel transmission

15544. Batch transmission

15545. Simplex transmission

15546. Serial transmission

15547. 239. (ECE Board Problem, November 1999) Which of the following antenna where its beamwidth is determine by the dimension of its horn, lens or reflector?

15548. Whip antenna

15549. Aperiodic antenna

15550. Aperture antenna

15551. Long wire antenna

15552. 240. (ECE Board Problem, April 1999) In a transoceanic satellite conversation, how much is the typical delay before a reply is heard?

15553. 200ms.

15554. 900ms.

15555. 50ms.

15556. 600ms.

15557. 241. (ECE Board Problem, November 2000)Position of the maritime ship main antenna, when the radio watch is secured or when the ship is in electrical storm.

15558. AA

15559. Main Transmitter

15560. Grounded

15561. HF

15562. 242. (ECE Board Problem, April 1999) Best applies to an optical fiber core.

15563. The same refractive index with the cladding

15564. A higher refractive index than the cladding

15565. A lower refractive index than the cladding 15566. A lower refractive index than air

15567.

15568. 243. (ECE Board Problem, November 1999) What measure will help you adopt on the antenna system of VHF or UHF mobile transceivers that has very low height antenna?

15569. Increase transmitter to antenna cable

15570. Use directional antenna

15571. Check grounding system

15572. Provide loading coil

15573. 244. (ECE Board Problem, April 1999)How do you account the effect of light intensity on the refractive index of a fiber optic?

15574. Decrease

15575. Stable

15576. Increase

15577. Decrease by half

15578.

15579. 245. (ECE Board Problem, November 1999) Refers to major advantage in the selection of a guided tube.

15580. Durability

15581. Low cost

15582. Accuracy

15583. High power

15584. 246. (ECE Board Problem, November 2000) This is the terminal where riser cable pairs are terminated to serve a portion or an entire floor of a building.

15585. Floor terminal distribution area

15586. Raceway terminal

15587. Floor distribution terminal

15588. Riser terminal 15589. 247. (ECE Board Problem, November 1999) This referred to a condition in a telephone network where the calling party cannot get connected to the party being called.

15590. Disconnection

15591. Open network

15592. Blocked call

15593. Loss call

15594. 248. (ECE Board Problem, April 2000) In data transmission technology, signals such as voice or video are binary transmitted over a cable known as______.

15595. Video signals

15596. Cable signals

15597. Baseband signals

15598. Audio signals

15599. 249. (ECE Board Problem, November 1999) In satellite communications where satellite revolves in an orbit that forms a plane passing through the center of gravity of the erath, this center is called______.

15600. Geocenter

15601. Earth center

15602. Plane center

15603. Center of gravity

15604. 250. (ECE Board Problem, November 1999) In television, the color with the most luminance is ______.

15605. Blue

15606. Green

15607. Yellow

15608. Red

15609. 251. (ECE Board Problem, April 2000) What do you call the dissipated power affecting the antenna efficiency caused by arching effect in high-powered transmitters?

15610. Dissipated power 15611. Antenna resistance

15612. Corona discharge

15613. Antenna loss

15614. 252. (ECE Board Problem, November 1999) What is the process in radio communication where information or intelligence signal at a lower frequency is put unto higher radio frequency for transmission to receiving station?

15615. Detection

15616. Mixing

15617. Modulation

15618. Demodulation

15619. 253. (ECE Board Problem, April 2000) An inductor that is inserted in an antenna element or transmission line for the purpose of producing a resonant system at specific.

15620. Reflector

15621. Traps

15622. Loading coil

15623. Base loading

15624. 254. (ECE Board Problem, November 2000) Satellite orbit around the earth are either, a) all are circular, b) all are elliptical, c) they are either circular or elliptical and d) none of these three.

15625. D

15626. B

15627. C

15628. A

15629. 255. (ECE Board Problem, April 2002) What is the main reason why television picture signal uses amplitude modulation, while voice is frequency modulated?

15630. Maintain the power signal at received end.

15631. Eliminate attenuation of both video and audio

15632. Maintain synchronized scanning between transmit and received video. 15633. To minimize interference between signals at received end

15634. 256. (ECE Board Problem, April 2002) Which of the following is referred to as a disadvantage of using squelch circuit?

15635. Effect of AGC is reduced for strong signals.

15636. Receiver sensitivity is reduced for strong signals.

15637. Very weak signals might not be received.

15638. Receiver selectivity is reduced for strong signals.

15639. 257. (ECE Board Problem, November 2000) How does spatial isolation technique in satellite communications avoid interference?

15640. Use of different polarity antennas.

15641. Use of different types of antenna.

15642. Employment of highly directional spot-beam

15643. Use of low gain antenna

15644. 258. (ECE Board Problem, November 2000) A parameter of light beam that do not change quantity when it enters one medium from another.

15645. Intensity

15646. Penetration

15647. Frequency

15648. Wavelength

15649. 259. (ECE Board Problem, November 2000) How far is the visual carrier from the aural in the monochrome television broadcast channel have?

15650. 1.5 MHz

15651. 3 MHz

15652. 4.5 MHz

15653. 1.25 MHz

15654. 260. (ECE Board Problem, November 2000) An order signed by former President F. Ramos last March 1998 providing the national policy in the operation and use of international satellite communication in the Philippines 15655. Executive Order 3846

15656. Executive Order 59

15657. Executive Order 456

15658. Executive Order 467

15659. 261. (ECE Board Problem, November 2000) Where does the Secretary General in the organizational structure of present ITU report?

15660. WTSG

15661. TDAB

15662. WRC

15663. Council

15664. 262. (ECE Board Problem, November 2000) In wire communication system using fiber optic, the packing fraction is related to one of the following statement when referred to fiber optic bundle.

15665. Ratio of the total fiber radius, to the sum of the fiber optic bundle radius.

15666. Ratio of half of the total fiber radius, to the sum of the fiber optic bundle radius.

15667. Ratio of half-sectional area of the fiber optic bundle, to the cross-sectional area of the core

15668. Ratio of the total cross-sectional area to the total cross-sectional area of the fiber bundle

15669. 263. (ECE Board Problem, April 2000) Determine the local oscillator frequency of a broadcast band receiver using a 455kHz IF and is tuned at 630kHz.

15670. 175 kHz

15671. 1085 kHz

15672. 280 kHz

15673. 1530 kHz

15674. 264. (ECE Board Problem, April 1999) One of the following is not a probable cause of radiating spurious signal from basic transmitter.

15675. Harmonics 15676. Regulated supply

15677. Internal heating

15678. Parasitic

15679. 265. (ECE Board Problem, April 2000) What is the purpose of the two Yagi beam antenna on a VHF TV receiver?

15680. Used to receiver VHF and UHF stations.

15681. For receiving low and high band stations.

15682. To increase selectivity

15683. To increase sensitivity on both hands.

15684.

15685. 266. (ECE Board Problem, November 2000) What is the noise that is develop in the RF amplifier front end of a TV receiver, which is indicated by a white dot in the picture?

15686. Inter carrier

15687. Black

15688. Snow

15689. IF

15690. 267. (ECE Board Problem, April 1999) Region in the atmosphere where ducting occurs?

15691. Ground region

15692. Stratosphere

15693. Ionosphere

15694. Troposphere

15695. 268. (ECE Board Problem, April 2000) Who issues an authority to install, operate, and maintain a cable television or render a television service within a specified area in the country?

15696. Department of Transportation and Communication.

15697. Board of Communication 15698. Congress of the Philippines

15699. National Telecommunications Communication

15700. 269. (ECE Board Problem, April 1999) What is the source of sidebands in frequency modulation?

15701. Oscillator

15702. Baseband Frequency

15703. Mixer

15704. Carrier Harmonics

15705. 270. (ECE Board Problem, November 2000) Which of the very thin layers of the tube’s front surface of the vidicon TV camera located at the middle layer and possess very high resistance when dark, while it reduces greatly when struck by photons of light?

15706. Transparent Conductive Film

15707. Photoresistive Layer

15708. Photo Inductive Lens

15709. Photosensitive Layer

15710. 271. (ECE Board Problem, April 2000) One of the following refers to the standard frequency band limits of AM broadcast band?

15711. 30-300 MHz

15712. 88-108 MHz

15713. 3-30 MHz

15714. 535-1605 kHz

15715. 272. (ECE Board Problem, November 2000)In a cable facilities for a building communications service,______is referred to as the physical cable within a building or series of buildings which may include both main cable pairs and house cable pairs but not station wiring cable?

15716. Entrance cable

15717. Floor distribution cable

15718. House cable 15719. Building cable

15720. 273. (ECE Board Problem, April 1999) What is the range of the lower sideband of an amplitude modulated signal whose carrier is 1.5 MHz and the intelligence component is 50 Hz to 20 kHz?

15721. 1.550 MHz to 1.700 MHz

15722. 1,499.980 kHz to 2,520.00 kHz

15723. 1.48 MHz to 1.4995 MHz

15724. 1,500.980 kHz to 2,480.00 kHz

15725. 274. (ECE Board Problem, November 2000) A stage in cellular communications where voice channel is assigned to link up a call connection after a mobile or network originated a call.

15726. Call termination

15727. Call completion

15728. Call connection

15729. Call drops

15730. 275. (ECE Board Problem, April 1999) How many satellites does not the GPS system consists?

15731. 12 satellites

15732. 3 satellites

15733. 24 satellites

15734. 60 satellites

15735. 276. (ECE Board Problem, April 2000) Ratio of radiation resistance to the total resistance on an antenna?

15736. Antenna gain

15737. Antenna sensitivity

15738. Antenna efficiency

15739. Antenna ratio

15740. 277. (ECE Board Problem, November 2000) What is the frequency of an LED at 1.9eV?

15741. 645 GHz

15742. 459 GHz

15743. 458 THz

15744. 337 THz

15745. 278. (ECE Board Problem, April 1999) One of the characteristics of a fiber optic used in order to carry light in several modes of propagation or to become a multimode fiber.

15746. Diameter of the core must be equal to the wavelength of the light to be carried.

15747. Diameter of the core must be very much greater than the wavelength of the light to be carried.

15748. Diameter of the core must be very small compared to the wavelength of light to be carried.

15749. Diameter of the core must be much half the wavelength of the light to be carried.

15750. 279. (ECE Board Problem, April 2000) One of the following is a communications filter generally used in the transceiver of a single sideband generator.

15751. Low-pass filter

15752. Crystal filter

15753. Bandpass filter

15754. Mechanical filter

15755. 280. (ECE Board Problem, April 2000) In computer communications, the term RS-232C is referred to as______.

15756. Analog connection standard

15757. Serial interference standard

15758. Digital connection standard

15759. Parallel port standard

15760.

15761. 15762.

15763.

15764.

15765.

15766.

15767.

15768.

15769.

15770.

15771.

15772.

15773.

15774.

15775.

15776.

15777.

15778. 15779. MULTIPLE CHOICE QUESTIONS IN 15780. ELECTRONICS SYSTEMS AND TECHNOLOGIES 15781. By 15782. Melvin C. Arceo

15783. 15784.

15785.

15786. 15787. ENCODED BY: 15788. ANDRADE, Caroline T. 15789. GARCIA, Virginia Nonna H. 15790. GIRAO, Edward Joseph D. 15791. LAQUI, Louise Ruelyn J. 15792. LORENZO, Luer Breech B. 15793. RIVERA, Billy Joe S. 15794. SAMONTE, Adrian A. 15795. SANTOLLO, Dan Alvin 15796. 15797. 15798. 15799. 15800. MULTIPLE CHOICE QUESTIONS IN 15801. BROADCAST ENGINEERING 15802. Electronics Systems and Technologies 15803. By 15804. Melvin C. Arceo

15805.

15806.

15807.

15808. 15809. 15810. 15811. ENCODED BY: 15812. ANDRADE, Caroline T. 15813. In stereophonic broadcast, the center frequency of each SCA subcarrier shall be kept at all times within ____ Hz of the authorized frequency. 15814. 15815. 200 15816. 300 15817. 400 15818. 500 15819. 15820. Sawtooth generator circuits produce the scanning raster, but the sync pulses are needed for 15821. 15822. Linearity 15823. Timing 15824. Keystoning 15825. Line pairing 15826. 15827. Which of the following camera tubes has minimum lag? 15828. 15829. Vidicon 15830. Plumbicon 15831. Saticon 15832. Iconoscope 15833. 15834. The service area in standard AM broadcast is described as ____ if there is no fading signal. 15835. 15836. Class A 15837. Secondary 15838. Class B 15839. Primary 15840. 15841. The vertical field-scanning frequency is _____ Hz. 15842. 15843. 30 15844. 60 15845. 525 15846. 15,750 15847. 15848. A 4.5-MHz signal which is equal to the difference between the picture and sound RF carrier frequencies in a 6-MHz TV channel. 15849. 15850. Audio frequency 15851. Video frequency 15852. Intercarrier frequency 15853. Subcarrier frequency 15854. 15855. A system where the modulated RF picture and sound carrier signals are distributed in a cable network, instead of wireless system. 15856. 15857. CCTV 15858. MATV 15859. CATV 15860. SATV 15861. 15862. A class A FM station is limited in antenna height of _____ feet above average terrain. 15863. 15864. 1000 15865. 2000 15866. 4000 15867. 5000 15868. 15869. What circuit in the TV receiver is used to develop the high voltage needed to operate the picture tube? 15870. 15871. Low-voltage power supply 15872. Horizontal output 15873. Vertical output 15874. Sync separator 15875. 15876. The modulated picture carrier wave includes the composite video signal as the 15877. 15878. Average carrier level 15879. Symmetric envelope of amplitude variations 15880. Lower sideband without the upper sideband 15881. Upper envelope without the lower envelope 15882. 15883. With which emission type is the capture-effect more pronounced? 15884. 15885. CW 15886. FM 15887. SSB 15888. AM 15889. 15890. The hue of color sync phase is 15891. 15892. Red 15893. Cyan 15894. Blue 15895. Yellow-green 15896. 15897. How much is the equivalent internal resistance of the electron beam with a 1.2- mA beam current at 25 kV? 15898. 15899. 48 nano ohms 15900. 30 ohms 15901. 20.8 mega ohms 15902. 15.6 kilo ohms 15903. 15904. The difference between the picture and sound carrier frequencies for channel 3 is ____ MHz. 15905. 15906. 3.58 15907. 64.5 15908. 4.5 15909. 6.75 15910. 15911. Refers to the deviation of the operating frequency of a crystal oscillator from its nominal value due to temperature variations. 15912. 15913. Drift 15914. Flashover 15915. Frequency deviation 15916. Deviation ratio 15917. 15918. It is the measure of how many picture elements can be reproduced 15919. 15920. Definition 15921. Resolution 15922. Detail 15923. Any of these 15924. 15925. A 3.58-MHz subcarrier signal for color in television 15926. 15927. Hue signal 15928. Video signal 15929. Audio signal 15930. Chroma signal 15931. 15932. A class D FM station shall have an authorized power not exceeding _____ watts. 15933. 15934. 20 15935. 15 15936. 10 15937. 5 15938. 15939. Which of the following is not a benefit of cable TV? 15940. 15941. Lower-cost reception 15942. Greater stability 15943. Less noise, stronger signal 15944. Premium cable channels 15945. 15946. The width of the vertical sync pulse in the Philippine TV system is 15947. 15948. 21H 15949. 3H 15950. H 15951. 0.5H 15952. 15953. Term in communication which is referred, “ to send out in all direction “ 15954. 15955. Announce 15956. Broadcast 15957. Transmit 15958. Media 15959. 15960. The number of frames per second in the Philippine TV system is 15961. 15962. 60 15963. 262 ½ 15964. 4.5 15965. 30 15966. 15967. It means multiple outlines of edges to the right in the picture. 15968. 15969. Ghosting 15970. Ringing 15971. Fading 15972. Snowing 15973. 15974. In the sawtooth waveform for linear scanning, 15975. 15976. The linear rise is for flyback 15977. The complete cycle includes trace and retrace 15978. The sharp reversal in amplitude produces trace 15979. The beam moves faster during trace and retrace 15980. 15981. The purpose of pre-emphasis and de-emphasis in FM broadcasting is to : 15982. 15983. Increase the high frequency amplitude 15984. Improve the audio harmonic 15985. Decrease the low frequency amplitude 15986. Improve the S/N ratio 15987. 15988. The part of the visible spectrum where camera pickup tubes have the greatest output is 15989. 15990. Red 15991. Blue 15992. Yellow-green 15993. Infrared 15994. 15995. The type of modulation of the sound carrier signal is ______. 15996. 15997. Pulse modulation 15998. Phase modulation 15999. Amplitude modulation 16000. Frequency modulation 16001. 16002. A video or audio signal that can be used directly to reproduce the picture and sound. 16003. 16004. Baseband signal 16005. Broadband signal 16006. Electromagnetic wave signal 16007. Modulated signal 16008. 16009. Class B FM station should have an ERP not exceeding ____ kW. 16010. 16011. 50 16012. 40 16013. 30 16014. 20 16015. 16016. What technique is used to permit hundreds of TV signals to share a common cable? 16017. 16018. Frequency modulation 16019. Mixing 16020. Frequency division multiplexing 16021. Time division multiplexing 16022. 16023. Another name for the horizontal retrace in a TV receiver is the 16024. 16025. Ringing 16026. Burst 16027. Damper 16028. Flyback 16029. 16030. In the Philippine color television system, the intercarrier frequency, in MHz, is 16031. 16032. 3.58 16033. 3.579545 16034. 4.5 16035. 45.75 16036. 16037. In channel 14 (470 to 476 MHz), the 3.58-MHz color signal is transmitted at 16038. 16039. 471.25 MHz 16040. 473.25 MHz 16041. 474.83 MHz 16042. 475.25 MHz 16043. 16044. Interfaced scanning eliminates 16045. 16046. Snowing 16047. Flicker 16048. Distortion 16049. Fading 16050. 16051. Beam alignment magnets for the camera tube are adjusted while rocking which control? 16052. 16053. Optical focus 16054. Electrical focus 16055. Beam current 16056. Shading 16057. 16058. What is the frequency discriminator? 16059. 16060. An FM generator 16061. A circuit for detecting FM 16062. A circuit for filtering two closely adjacent signals 16063. An automatic bandwidth circuit 16064. 16065. A system used in television field operation to make on the spot video tape recordings using portable TV cameras and VTRs. 16066. 16067. SNG 16068. ENG 16069. HAFC 16070. MATV 16071. 16072. Class B FM station shall have an authorized transmitter power not exceeding ______kW. 16073. 16074. 10 16075. 100 16076. 1000 16077. 10000 16078. 16079. The total bandwidth of an NTSC TV signal is 16080. 16081. 3.58 MHz 16082. 4.5 MHz 16083. 6 MHz 16084. 10.7 MHz 16085. 16086. Referred to the oscillator signal “leak through” from a property neutralized amplifier such as a master oscillator power amplifier. 16087. 16088. Carrier 16089. Stray signal 16090. Back wave 16091. Loss wave 16092. 16093. Interfacing is used in television to 16094. 16095. Produce the illusion of motion 16096. Ensure that all lines on the screen are scanned, not merely the alternate ones 16097. Simplify the vertical sync pulse train 16098. Avoid flicker 16099. 16100. Coaxial cable for distribution system has an impedance of 16101. 16102. 50 ohms 16103. 75 ohms 16104. 150 ohms 16105. 300 ohms 16106. 16107. The average voltage value of the 3.58-MHz modulated chrominance signal is 16108. 16109. Zero for most colors 16110. Close to black for yellow 16111. The brightness of the color 16112. The saturation of the color 16113. 16114. When does broadcast station conduct an equipment test? 16115. 16116. During day time 16117. During night time 16118. During experimental period 16119. At any time 16120. 16121. It causes the picture information to spread out or crowded at one end of the raster compared to the opposite end. 16122. 16123. Linear scanning 16124. Interfaced scanning 16125. Non-linear scanning 16126. Retrace 16127. 16128. If the camera cannot be placed far away enough to include everything in the scene, change the lens to one with a 16129. 16130. Lower f rating 16131. Higher f rating 16132. Longer focal length 16133. Shorter focal length 16134. 16135. Type of radio communication transmission utilizing frequency modulation technique 16136. 16137. Television video 16138. Broadcasting in 535-1606 kHz 16139. Single sideband HF transmission 16140. Television audio 16141. 16142. The amount of color in the picture or color intensity is the ______. 16143. 16144. Color level 16145. Chroma level 16146. Saturation 16147. Any of these 16148. 16149. One of the early radio transmitters which produced keyed carrier generating purer waveform than spark transmitter, used for high powered RF transmission and are limited to radio frequency of about 500 kHz. 16150. 16151. Arc transmitter 16152. Hartley transmitter 16153. Spark transmitter 16154. Frequency transmitter 16155. 16156. A technique where segments of videotape are joined by electronic erasing and recording to create a single program. 16157. 16158. Masking 16159. Segmenting 16160. Editing 16161. Programming 16162. 16163. A class C FM station has an authorized radiated power not exceeding ____watts of ERP. 16164. 16165. 500 16166. 750 16167. 1000 16168. 2000 16169. 16170. The assembly around the neck of a picture tube that produces the magnetic fields that deflect and scan the electron beams is called the 16171. 16172. Shadow mask 16173. Phosphor 16174. Electron gun 16175. Yoke 16176. 16177. An odd number of lines per frame forms part of every one of the world’s TV systems. This is 16178. 16179. Done to assist interlace 16180. Purely an accident 16181. To ensure that line and frame frequencies can be obtained from the same original source 16182. Done to minimize interference with the chroma subcarrier 16183. 16184. The difference between the sound carrier and the color signal is 16185. 16186. 4.5 MHz 16187. 1.25 MHz 16188. 0.92 MHz 16189. 0.25 MHz 16190. 16191. In color television, it is made for uniform color in the raster. 16192. 16193. Beam-landing adjustment 16194. Degaussing 16195. Internal blanking adjustment 16196. Background control 16197. 16198. Which of the following camera tubes uses load oxide for the photoconductive target plate? 16199. 16200. Vidicon 16201. Plumbicon 16202. Saticon 16203. Image orthicon 16204. 16205. The number of fields is _____ per frame. 16206. 16207. 2 16208. 60 16209. 525 16210. 262 ½ 16211. 16212. An RF carrier wave that is frequency-modulated by the baseband audio signal in TV broadcasting. 16213. 16214. Audio signal 16215. Video Signal 16216. Intercarrier signal 16217. Color signal 16218. 16219. A class B FM station is limited in antenna height of _____ feet. 16220. 16221. 1000 16222. 500 16223. 250 16224. 100 16225. 16226. The HV anode supply for the picture tube of a TV receiver is generated in the 16227. 16228. Mains transformer 16229. Vertical output stage 16230. Horizontal output stage 16231. Horizontal deflection oscillator 16232. 16233. A tap for the subscriber drop line has a 16234. 16235. High insertion loss 16236. High tap loss 16237. Low tap loss 16238. 300-ohm 16239. 16240. Which system can be used for both recording and playback? 16241. 16242. CED 16243. VHD 16244. Laser disk 16245. VHS 16246. 16247. The hue 180 degrees out of phase with red is 16248. 16249. Cyan 16250. Yellow 16251. Green 16252. Blue 16253. 16254. It is used around the phosphor dots to make a darker black which improves contrast in the picture. 16255. Black masking 16256. Convergence adjustment 16257. Shadow masking 16258. Color purity adjustment 16259. 16260. A lens lower f rating is ____ lens that allows more light input. 16261. 16262. Slower 16263. Wider 16264. Narrower 16265. Faster 16266. 16267. Picture frames are repeated at the rate of ____ per second. 16268. 16269. 30 16270. 60 16271. 45 16272. 50 16273. 16274. The effective radiated power of a class A FM station should not exceed _____ kW. 16275. 16276. 125 16277. 30 16278. 10 16279. 1 16280. 16281. In television, 4:3 represents the 16282. 16283. Interface ratio 16284. Maximum horizontal deflection 16285. Aspect ratio 16286. Ratio of the two diagonals 16287. 16288. Titling the video head gaps is necessary with the 16289. 16290. Color-under 16291. Zero guard bands 16292. FM luminance signal 16293. Long-play tapes 16294. 16295. It is a special camera tube with a test pattern in the image plate. 16296. 16297. Vidicon 16298. Monoscope 16299. Oscilloscope 16300. Iconoscope 16301. 16302. The number of lines scanned per frame in the raster on the picture tube screen is 16303. 16304. 525 16305. 262 ½ 16306. 20 16307. 10 16308. 16309. One of the following is a high powered RF ac basic transmitter that has two or more stages, the oscillator stage which determines the frequency of operation and RF amplifier stage or stages that develop the high power output. The purpose of which is to develop a good frequency stability. 16310. 16311. MOPA 16312. Hartley 16313. Alexanderson 16314. Goldsmith 16315. 16316. Camera signal output without sync is called ______. 16317. 16318. Black burst 16319. Generator lock video 16320. Composite video 16321. Non-composite video 16322. 16323. The tint of the color is its 16324. 16325. Brightness 16326. Contrast 16327. Chroma 16328. Hue 16329. 16330. Which frequency band is the standard AM radio broadcast? 16331. 16332. HF 16333. UHF 16334. MF 16335. VHF 16336. 16337. The I and Q composite color signals are multiplexed onto the picture carrier by modulating a 3.58 MHz subcarrier using 16338. 16339. FM 16340. PM 16341. DSB AM 16342. Vestigial sideband AM 16343. 16344. The shadow mask in a color picture tube is used to 16345. 16346. Reduce X-ray emission 16347. Ensure that each beam hits only its own dots 16348. Increase screen brightness 16349. Provide degaussing for the screen 16350. 16351. The video heads rotate at high velocity to increase the 16352. 16353. Tape speed 16354. Writing speed 16355. Reel rotation 16356. Tape tension 16357. 16358. How ho you eliminate radio frequency variation of an oscillator transmitter caused by its supply voltage? 16359. 16360. Use of regulated power supply 16361. Use of new power supply 16362. Use of high capacitor in the supply circuit 16363. Loosen power supply shielding 16364. 16365. The composite video signal includes the camera signal with the following except 16366. 16367. Picture information 16368. Sync pulses 16369. Blanking pulses 16370. Camera signal 16371. 16372. A lens has an 8-cm focal length and 4-cm diameter. Its f rating is 16373. 16374. 2 16375. 4 16376. 8 16377. 32 16378. 16379. Which of the following is a possible cause for an abrupt frequency variation in a self-excited transmitter oscillator circuits resulting a poor frequency stability to hold a constant frequency oscillation? 16380. 16381. DC and RF AC heating of resistor which cause a change in values 16382. Heating and expansion of oscillator coil 16383. Heating of capacitor in the oscillator 16384. Power supply voltage changes 16385. 16386. How long does it take to scan 2 picture elements when 400 are scanned in 50 microseconds? 16387. 16388. 25 microsec 16389. 0.25 microsec 16390. 2.5 microsec 16391. 0.5 microsec 16392. 16393. Anode voltage for the picture tube, developed from the output of the horizontal deflection circuit. 16394. 16395. Yoke voltage 16396. Flyback voltage 16397. Aquadag voltage 16398. Tube voltage 16399. 16400. The channel spacing in the Philippine FM broadcast standards 16401. 16402. 400 kHz 16403. 800 kHz 16404. 600 kHz 16405. 200 kHz 16406. 16407. What is the black-and-white or monochrome brightness signal in TV called? 16408. 16409. RGB 16410. Color subcarrier 16411. Q and I 16412. Luminance Y 16413. 16414. Which of the following is a midband cable TV channel? 16415. 16416. 6 16417. 7 16418. 14 16419. 23 16420. 16421. What is the primary purpose of an RF amplifier in a receiver? 16422. 16423. To vary the receiver image rejection by utilizing the AGC 16424. To provide most of the receiver gain 16425. To develop the AGC voltage 16426. To improve the receiver’s noise figure 16427. 16428. The color with the most luminance is 16429. 16430. Red 16431. Yellow 16432. Green 16433. Blue 16434. 16435. It is the light flux intercepted by one-foot-square surface that is one foot from one-candlepower source. 16436. 16437. Candela 16438. Footcandle 16439. Lux 16440. Lumens 16441. 16442. Refers to the possible cause for an abrupt frequency variations in a self-excited transmitter oscillator circuit resulting to a poor frequency stability to hold a constant oscillator. 16443. 16444. Poor soldered connections 16445. Heating of capacitor in the oscillator 16446. DC and AC heating of resistors which cause change in values 16447. Aging which cause change in condition in parts characteristics 16448. 16449. It is the difference in intensity between the black parts and white parts of the picture. 16450. 16451. Brightness 16452. Hue 16453. Contrast 16454. Illumination 16455. 16456. The stereophonic subcarrier suppression level in the Philippines standards 16457. 16458. Less than 4% modulation of the main carrier 16459. Less than 3% modulation of the main carrier 16460. Less than 2% modulation of the main carrier 16461. Less than 1% modulation of the main carrier 16462. 16463. The sound IF in a TV receiver is 16464. 16465. 4.5 MHz 16466. 10.7 MHz 16467. 41.25 MHz 16468. 45.75 MHz 16469. 16470. The circuit separates sync pulse from the composite video waveform is 16471. 16472. The keyed AGC amplifier 16473. A clipper 16474. An integrator 16475. A differentiator 16476. 16477. In the CED system, the disk capacitance varies with the 16478. 16479. Pit depth 16480. Disk size 16481. Speed of rotation 16482. Wavelength of the scanning light 16483. 16484. The final power amplifier in an FM transmitter usually operates class _____ 16485. 16486. AB 16487. C 16488. B 16489. A 16490. 16491. In a picture tube, it is the total angle that the beam can be deflected without touching the sides of the envelope. 16492. 16493. Screen angle 16494. Tube angle 16495. Picture angle 16496. Deflection angle 16497. 16498. It is necessary to time the scanning with respect to picture information. 16499. 16500. Flyback 16501. Synchronization 16502. Blanking 16503. Scanning 16504. 16505. The intermediate frequency used in for FM broadcasting Philippine standards. 16506. 16507. 455 kHz 16508. 10.7 MHz 16509. 11.4 MHz 16510. 12.5 MHz 16511. 16512. What is the horizontal scanning time for 20 pixels? 16513. 16514. 2.5 microsec 16515. 0.25 microsec 16516. 1.25 microsec 16517. 125 microsec 16518. 16519. In basic radio transmitter, the main advantage of a single-tube transmitter is 16520. 16521. Frequency instability 16522. Non-portable 16523. Heating effect 16524. Bulky 16525. 16526. The carrier transmitted 1.25 MHz above the bottom frequency in a Philippine TV channel is the 16527. 16528. Sound carrier 16529. Chroma carrier 16530. Intercarrier 16531. Picture carrier 16532. 16533. In camera tubes, it means that the old image remains too long after the picture information on the target plate has changed. 16534. 16535. Light lag 16536. Switch lag 16537. Image lag 16538. Camera lag 16539. 16540. What is the maximum color TV bandwidth? 16541. 16542. 1.6 MHz 16543. 0.5 MHz 16544. 1.0 MHz 16545. 1.3 MHz 16546. 16547. Class of FM station where its authorized power should not exceed 15 kW. 16548. 16549. Class A 16550. Class B 16551. Class C 16552. Class D 16553. 16554. What is the name of the solid state imaging device used in TV cameras that converts the light in a scene into an electrical signal? 16555. 16556. CCD 16557. Phototube matrix 16558. Vidicon 16559. MOSFET array 16560. 16561. The signals sent by the transmitter to ensure correct scanning in the receiver is called 16562. 16563. Sync 16564. Chroma 16565. Luminance 16566. Video 16567. 16568. What signals are transmitted by a SSBSC transmitter when no modulating signal is present? 16569. 16570. The upper sideband only 16571. Both the upper and lower sideband 16572. The lower sideband 16573. No signal transmitted 16574. 16575. The second IF value for color in receivers, for any station, is 16576. 16577. 0.5 MHz 16578. 1.3 MHz 16579. 3.58 MHz 16580. 4.5 MHz 16581. 16582. In the frame for which interfaced scanning is used, alternate lines are skipped during vertical scanning because 16583. 16584. The trace is slower than retrace 16585. The vertical scanning frequency is doubled from 30 to 60 Hz 16586. The horizontal scanning is slower than vertical scanning 16587. The frame has a 4:3 aspect ratio 16588. 16589. A typical value of vidicon dark current is 16590. 16591. 0.2 microampere 16592. About 200 microampere 16593. 8 milliampere 16594. 800 milliampere 16595. 16596. The smallest are of light or shade in the image is a picture element called 16597. 16598. Chroma 16599. Hue 16600. Contrast 16601. Pixel 16602. 16603. An entry of the time the station begins to supply power to the antenna and the time it stops. 16604. 16605. Operating log entries 16606. Program log entries 16607. Operating schedule 16608. Any of these 16609. 16610. What type of circuit is used to modulate and demodulate the color signals? 16611. 16612. Phase-locked loop 16613. Differential peak detector 16614. Quadrature detector 16615. Balanced modulator 16616. 16617. This is referred to as a fixed radio station that broadcast program material from audio to transmitter by radio link. 16618. 16619. Aural BC intercity relay 16620. Aural broadcast STL 16621. Short wave station 16622. Remove pick-up 16623. 16624. Indicate which of the following frequencies will not be found in the output of a normal TV receiver tuner. 16625. 16626. 4.5 MHz 16627. 41.25 MHz 16628. 45.75 MHz 16629. 42.17 MHz 16630. 16631. In all standard television broadcast channels , the difference between the picture and sound carrier frequencies is 16632. 16633. 0.25 MHz 16634. 1.25 MHz 16635. 4.5 MHz 16636. 6 MHz 16637. 16638. It is caused by phase distortion for video frequencies of about 100 kHz and lower. 16639. 16640. Streaking 16641. Snowing 16642. Ringing 16643. Fading 16644. 16645. Special effects and production switching are done by the 16646. 16647. CCU 16648. ENG camera 16649. SEG 16650. Sync generator 16651. 16652. A picture has 400 horizontal and 300 vertical picture elements. What is the total number of details in the picture? 16653. 16654. 120,000 16655. 700 16656. 0.75 16657. 100 16658. 16659. After the IF stages have been aligned, the next stage to align in FM receiver is 16660. 16661. Local oscillator 16662. Limiter stage 16663. RF amplifier 16664. Mixer stage 16665. 16666. What ensures proper color synchronization at the receiver? 16667. 16668. Sync pulses 16669. Quadrature modulation 16670. 4.5-MHz intercarrier sound 16671. 3.58-MHz color burst 16672. 16673. The interfering beat frequency of 920 kHz is between the 3.58-MHz color subcarrier and the 16674. 16675. 4.5-MHz intercarrier sound 16676. Picture carrier 16677. Lower adjacent sound 16678. Upper adjacent picture 16679. 16680. Light is converted to video signal by the _____ tube. 16681. 16682. Camera tube 16683. Picture tube 16684. Anode tube 16685. Cathode tube 16686. 16687. The frequency spectrum of the stereophonic FM signal. 16688. 16689. 67 kHz 16690. 59.5 to 74.5 kHz 16691. 19 to 38 kHz 16692. 30 to 53 kHz 16693. 16694. Equalizing pulses in TV are sent during 16695. 16696. Horizontal blanking 16697. Vertical blanking 16698. The serrations 16699. The horizontal retrace 16700. 16701. Which signal has color information for 1.3 MHz bandwidth? 16702. 16703. I 16704. Y 16705. R-Y 16706. B-Y 16707. 16708. It is the distance from the center of the lens of the camera to the point at which parallel rays from a distant object come to a common focal point. 16709. 16710. Focal length 16711. Latus rectum 16712. Major axis 16713. Minor axis 16714. 16715. The method of generating FM used by broadcast station is 16716. 16717. Direct 16718. Indirect 16719. Insertion 16720. All of these 16721. 16722. The picture and sound carrier frequencies in a TV receiver IF are respectively. 16723. 16724. 41.25 and 45.75 MHz 16725. 45.75 and 41.25 MHz 16726. 41.75 and 45.25 MHz 16727. 45.25 and 41.75 MHz 16728. 16729. The channel width in the Philippine TV system, in MHz, is 16730. 16731. 41.25 16732. 6 16733. 4.5 16734. 3.58 16735. 16736. The cable converter output or the TV receiver is usually on channel 16737. 16738. 3 16739. 6 16740. 7 16741. 9 16742. 16743. One-half line spacing between the start positions for scanning even and odd fields produces 16744. 16745. Linear scanning 16746. Line pairing 16747. Fishtailing 16748. Exact interlacing 16749. 16750. Precise scanning size and linearity are most important in 16751. 16752. A black-and-white camera 16753. Plumbicon 16754. A single-tube color pickup 16755. A saticon 16756. 16757. A signal in which the sum of all signals which frequency-modulates the main carrier. 16758. 16759. Composite baseband signal 16760. FM baseband 16761. Main channel signal 16762. Stereophonic signal 16763. 16764. What is the total number of interlaced scan lines in one complete frame of a NTSC Philippine TV signal? 16765. 16766. 262 ½ 16767. 525 16768. 480 16769. 625 16770. 16771. The video voltage applied to the picture tube of a television receiver is fed in 16772. 16773. Between grid and ground 16774. To the yoke 16775. To the anode 16776. Between the grid and cathode 16777. 16778. How many dBmV units correspond to a 1-mV signal level? 16779. 16780. 0 16781. 1 16782. 3 16783. 6 16784. 16785. In color television, it is made to maintain neutral white from low to high levels of brightness. 16786. 16787. Internal color adjustment 16788. Color-temperature adjustments 16789. Shadow masking 16790. Convergence adjustment 16791. 16792. Average power of a radio transmitter supplied to the antenna transmission line by a transmitter during one radio frequency cycle taken under the condition or no modulation. 16793. 16794. Peak envelope power 16795. Rated power 16796. Carrier power 16797. Mean power 16798. 16799. The number of scanning lines is ____ per second. 16800. 16801. 525 16802. 262 ½ 16803. 15,750 16804. 30 16805. 16806. The ratio of the actual frequency swing to the frequency swing defined as 100 percent modulation, expressed in percentage. 16807. 16808. Modulation index 16809. Deviation ration 16810. Maximum deviation 16811. Percentage modulation 16812. 16813. In a TV receiver, the color killer 16814. 16815. Cuts off the chroma stages during monochrome reception 16816. Ensures that no color is transmitted to monochrome receivers 16817. Prevents color coding 16818. Make sure that the color burst is not mistaken for sync pulses, by cutting off reception during the back porch. 16819. 16820. How many TV fields are recorded on one slant track of tape? 16821. 16822. 1 16823. 2 16824. 4 16825. 60 16826. 16827. A communication circuit using class C amplifier is considered a narrow band amplifier if the bandwidth is less than _____ % of its resonant frequency. 16828. 16829. 15 16830. 13 16831. 10 16832. 20 16833. 16834. The width of a vertical sync pulse with its serrations includes the time of 16835. 16836. Six half-lines, or three lines 16837. Five lines 16838. Three half-lines 16839. Five half-lines 16840. 16841. A low-contrast picture in which white seems flat and lacking in detail suggests 16842. 16843. Low beam current 16844. High gain in the pre-amplifier 16845. Excessive gamma 16846. Insufficient scanning width 16847. 16848. The product of the transmitter power multiplied by the antenna power gain of the antenna field gain squared. 16849. 16850. Field intensity 16851. Field gain 16852. ERP 16853. Electric field strength 16854. 16855. What keeps the scanning process at the receiver in step with the scanning in the picture tube at the receiver? 16856. 16857. Nothing 16858. Sync pulses 16859. Color burst 16860. Deflection oscillators 16861. 16862. The number of lines per second in the TV system is 16863. 16864. 31,500 16865. 15,700 16866. 262 ½ 16867. 525 16868. 16869. In a basic transmitter, ______is a kind of transmitter that develops type B emission. 16870. 16871. Arc 16872. Spark 16873. Alexanderson 16874. High end 16875. 16876. It is a number that indicates how contrast is expanded or compressed. 16877. 16878. Alpha 16879. Beta 16880. Gamma 16881. Sigma 16882. 16883. Color picture tubes have ______guns for its phosphors. 16884. 16885. 1 16886. 2 16887. 3 16888. 4 16889. 16890. The FM broadcast band is divided into _____ channels are suggested by KBP. 16891. 16892. 200 16893. 100 16894. 50 16895. 25 16896. 16897. The output of the vertical amplifier, applied to the yoke in a TV receiver, consists of 16898. 16899. Direct current 16900. Amplified vertical sync pulse 16901. A sawtooth voltage 16902. A sawtooth current 16903. 16904. The frequency spectrum of the stereophonic FM signal. 16905. 16906. 67 kHz 16907. 59.5 kHz to 74.5 kHz 16908. 19 kHz to 38 kHz 16909. 30 kHz to 53 kHz 16910. 16911. What is the video frequency response corresponding to the horizontal resolution of 200 lines? 16912. 16913. 4 MHz 16914. 1.5 MHz 16915. 4.5 MHz 16916. 2.5 MHz 16917. 16918. The gamma of the picture tube is 16919. 16920. 0.4545 16921. 1.0 16922. 1.4 16923. 2.2 16924. 16925. It is the instantaneous departure of the frequency of the emitted wave from the center frequency resulting from modulation. 16926. 16927. Deviation 16928. Frequency swing 16929. Phase shift 16930. Deviation ratio 16931. 16932. If a TV sound transmitter has a carrier frequency of 197.75 MHz, the picture carrier is 16933. 16934. 191.75 MHz 16935. 193.25 MHz 16936. 202.25 MHz 16937. 203.75 MHz 16938. 16939. The number of lines per field in the Philippine TV system is 16940. 16941. 262 ½ 16942. 525 16943. 30 16944. 60 16945. 16946. What is the best site of an AM broadcast transmitter? 16947. 16948. Marshy land 16949. Dry land 16950. Highly elevated 16951. Average terrain 16952. 16953. What is the hue of a color 90 degrees leading sync burst phase? 16954. 16955. Yellow 16956. Cyan 16957. Blue 16958. Orange 16959. 16960. The two black conductive coatings of picture tubes are made up of 16961. 16962. Phosphor 16963. Aquadag 16964. Cavity 16965. Nickel 16966. 16967. The maximum power allocation of AM transmitter in Metro Manila in kW is 16968. 16969. 10 kW 16970. 20 kW 16971. 40 kW 16972. 30 kW 16973. 16974. The function of the serrations in the composite video waveforms is to 16975. 16976. Equalize the change in the integrator before the start of vertical retrace 16977. Help vertical synchronization 16978. Help horizontal synchronization 16979. Simplify the generation of the vertical sync pulse 16980. 16981. Which system uses a light beam for playback? 16982. 16983. CED 16984. VHD 16985. Betamax 16986. VLP 16987. 16988. Weak emission from one cathode in a tricolor picture tube causes 16989. 16990. A weak picture 16991. A long warmup time 16992. A color imbalance in the raster and picture 16993. All of these 16994. 16995. In AM broadcast, the current carrier shift at any percentage of modulation shall not exceed 16996. 16997. 5% 16998. 15% 16999. 20% 17000. 2.5% 17001. 17002. Indicate which voltages are not found in the output of a normal monochrome receiver video detector. 17003. 17004. Sync 17005. Video 17006. Sweep 17007. Sound 17008. 17009. The sawtooth waveform for deflection provides ______. 17010. 17011. Horizontal deflection 17012. Distortions 17013. Linear scanning 17014. Flicker 17015. 17016. In AM broadcast, the transmitter must be capable of maintaining the operating frequency within the limits of ______. 17017. 17018. +/- 10 Hz 17019. +/- 20 Hz 17020. +/- 25 Hz 17021. +/- 75 Hz 17022. 17023. How much illumination in lux a 400-candlepower make that is 3 meters from the surface? 17024. 17025. 133.3 17026. 1200 17027. 200 17028. 44.4 17029. 17030. Brightness variations of the picture information are in which signal? 17031. 17032. I 17033. Q 17034. Y 17035. R-Y 17036. 17037. How many octaves is the frequency range of 1 to 8 MHz? 17038. 17039. 1 17040. 2 17041. 3 17042. 8 17043. 17044. For television, the maximum deviation of the FM sound signal in kHz. 17045. 17046. 10 17047. 25 17048. 75 17049. 100 17050. 17051. Indicate which of the following signals is not transmitted in color TV 17052. 17053. Y 17054. Q 17055. R 17056. I 17057. 17058. Emission outside of the assigned channel, as a result of the modulation process. 17059. 17060. Overmodulation 17061. Spurious emission 17062. Out-of-band emission 17063. In band emission 17064. 17065. Determine which of the following is not part of RF section of a radio transmitter. 17066. 17067. Master oscillator 17068. Buffer amplifier 17069. AF voltage amplifier 17070. Frequency amplifier 17071. 17072. The power of any conducted spurious emission shall be attenuated below the maximum level of carrier frequency in accordance with the following formula: 17073. 17074. Attenuation (dB) = 43 + 20 log P 17075. Attenuation (dB) = 43 + log P 17076. Attenuation (dB) = 43 + 10 log P 17077. Attenuation (dB) = 43 + log P/10 17078. 17079. In television, gamma affects _____ 17080. 17081. Color 17082. Contrast 17083. Brightness 17084. Hue 17085. 17086. In the IRE scale for the composite video signal, what is the number of IRE units for sync? 17087. 17088. 7.5 17089. 92.5 17090. 40 17091. 10 17092. 17093. As prescribed by the technical standards for Cable Television operation and in order to be compatible for any value added services in the future, Trunk cable should have a minimum diameter of ______. 17094. 17095. 0.25 inch 17096. 0.5 inch 17097. 0.75 inch 17098. 1.0 inch 17099. 17100. Compared with 100 percent saturation, the desaturated color have 17101. 17102. More luminance for the Y signal 17103. Less luminance for the Y signal 17104. More chrominance for the C signal 17105. Less hue for the C signal 17106. 17107. What is the practical baseband frequency for the color video signal? 17108. 17109. 1 MHz 17110. 2 MHz 17111. 0.2 MHz 17112. 0.5 MHz 17113. 17114. What is the diagonal screen size for the 19CP4 picture tube? 17115. 17116. 21 17117. 23 17118. 4 17119. 19 17120. 17121. What is the phase angle between B – Y and R – Y? 17122. 17123. 180 deg 17124. 45 deg 17125. 90 deg 17126. 270 deg 17127. 17128. How many gray scale steps are in the EIA test pattern in television? 17129. 17130. 10 17131. 40 17132. 50 17133. 15 17134. 17135. In TV, degaussing is done with _____. 17136. 17137. Direct current 17138. Pulsed current 17139. Alternating current 17140. Any of these 17141. 17142. R, G and B video drive controls set for ______. 17143. 17144. Black 17145. Dark gray 17146. White 17147. Light gray 17148. 17149. What is the phase difference between the color sync burst and the B – Y video? 17150. 17151. 180 deg 17152. 45 deg 17153. 90 deg 17154. 270 deg 17155. 17156. What is the hue of the color sync burst? 17157. 17158. Yellow-green 17159. Red 17160. Blue 17161. Orange 17162. 17163. What synchronizes the horizontal of the TV picture tube? 17164. 17165. HSC 17166. HAFC 17167. HFC 17168. HAC 17169. 17170. What is the typical anode voltage for a 25-inch color picture tube? 17171. 17172. 3 kV 17173. 20 kV 17174. 10 kV 17175. 30 kV 17176. 17177. In television, what is the phosphor number for monochrome picture tube? 17178. 17179. P4 17180. P21 17181. P22 17182. P3 17183. 17184. In television picture tube, what is the color of the P1 phosphor? 17185. 17186. Red 17187. Green 17188. Yellow 17189. Blue 17190. 17191. What video frequency corresponds to 240 lines of horizontal resolution? 17192. 17193. 1 MHz 17194. 3 MHz 17195. 2 MHz 17196. 4 MHz 17197. 17198. The minimum FM broadcast transmitter power in metro manila and metro cebu is 17199. 17200. 25 kW 17201. 10 kW 17202. 1 kW 17203. 30 kW 17204. 17205. The maximum power suggested by KBP on 919-1312 AM broadcast station in Metro Manila. 17206. 17207. 10 kW 17208. 20 kW 17209. 15 kW 17210. 5 kW 17211. 17212. What are the frequency limits of the standard AM broadcast band? 17213. 17214. 565 to 1605 kHz 17215. 535 to 1605 kHz 17216. 575 to 1615 kHz 17217. 535 to 1615 kHz 17218. 17219. What is the width of an AM broadcast channel? 17220. 17221. 30 kHz 17222. 25 kHz 17223. 15 kHz 17224. 200 kHz 17225. 17226. The following are designations of service areas of AM broadcast station, except: 17227. 17228. Primary 17229. Secondary 17230. Tertiary 17231. Intermittent 17232. 17233. The following are parts of the AM broadcast day, except: 17234. 17235. Daytime 17236. Night time 17237. Mid-day 17238. Experimental period 17239. 17240. Why is it desirable to have broadcast antennas on marshy land? 17241. 17242. For better reflection 17243. For ground wave radiation 17244. For greater absorption 17245. For sky wave propagation 17246. 17247. What is another name for a console pot? 17248. 17249. Attenuator 17250. Gain control 17251. Fader 17252. Any of these 17253. 17254. The highest peaks of modulation in AM should be held between what two percentages? 17255. 17256. 85-100% 17257. 65-70% 17258. 50-75% 17259. 75-90% 17260. 17261. What is the name of the second transmitter used when a station operates 24 hours a day? 17262. 17263. Alternate 17264. Reserve 17265. Spare 17266. Diversity 17267. 17268. What is a combo operator? 17269. 17270. Announcer 17271. Disk jockey 17272. Engineer 17273. All of these 17274. 17275. What term is used to indicate intercom operation in a broadcast station? 17276. 17277. Communication 17278. Talk-back 17279. Respond 17280. Remote talk 17281. 17282. What does a red light glowing in a studio indicate? 17283. 17284. Off the air 17285. Floating 17286. Experimental 17287. On the air 17288. 17289. What is the attenuator which controls the the output of the program amplifier called? 17290. 17291. Master gain control 17292. Auxiliary gain control 17293. Reserve frequency control 17294. Auxiliary frequency control 17295. 17296. The following are important operational requirements during a broadcast, except: 17297. 17298. Timing 17299. Modulation 17300. Fidelity 17301. AF amplitude 17302. What are the names of two unbalanced pads used in broadcasting? 17303. 17304. T and L 17305. K and P 17306. R and I 17307. H and L 17308. 17309. What is the advantage of using balanced lines in audio systems? 17310. 17311. Receive balanced sound 17312. Improve fidelity 17313. Reduce noise pickup 17314. Improve carrier level 17315. 17316. What is the advantage of using T-pad attenuators over potentiometers? 17317. 17318. Better energy conversion 17319. Better attenuation 17320. Match impedance better 17321. Any of these 17322. 17323. What device is used to make up for the high-frequency losses in long AF lines? 17324. 17325. Signal booster 17326. Noise suppressor 17327. Line equalizer 17328. Compander 17329. 17330. What is another term meaning “operating power” 17331. 17332. Licensed power 17333. Sideband power 17334. Audio power 17335. Harmonic power 17336. 17337. What does maximum rated carrier power referred to? 17338. 17339. Buffer amplifier power rating 17340. Intermediate amplifier power rating 17341. Speech amplifier power rating 17342. Final-amplifier power rating 17343. 17344. When are equipment tests made? 17345. 17346. Mid-day 17347. Daytime 17348. Night time 17349. Experimental period 17350. 17351. What is the maximum allowable distortion at 80% modulation? 17352. 17353. 3% 17354. 4% 17355. 5% 17356. 6% 17357. 17358. On what are proof-of-performance tests in broadcasting made? 17359. 17360. Omnidirectional antennas 17361. Directive antennas 17362. High gain antennas 17363. Any of these 17364. 17365. Within what limits must the antenna current ratios of a directional antenna be held? 17366. 17367. 3% 17368. 5% 17369. 4% 17370. 1% 17371. 17372. What monitor is required at the operating position in a broadcast station? 17373. 17374. Frequency 17375. Modulation 17376. Fidelity 17377. Carrier 17378. 17379. What monitor may also give an indication of carrier amplitude regulation? 17380. 17381. Modulation 17382. Carrier 17383. Fidelity 17384. Frequency 17385. 17386. What device can give the most accurate instantaneous peak-of-modulation indications? 17387. 17388. Spectrum analyzer 17389. Fourier analyzer 17390. CRT oscilloscope 17391. Frequency probe 17392. 17393. The item required in program log? 17394. 17395. Identification 17396. Program description 17397. Sponsors and network name 17398. All of these 17399. 17400. The item required in an operating log? 17401. 17402. Antenna power and programs on-off 17403. EBS tests 17404. Any of these 17405. Antenna lights and meter readings 17406. 17407. The item required in a maintenance log? 17408. 17409. Any of these 17410. Antenna current checks 17411. Meter replacements 17412. Light inspection and experimental period operation 17413. 17414. What is the minimum time broadcast station logs must be held? 17415. 17416. One year 17417. Two years 17418. Three years 17419. Five years 17420. 17421. What class operator has no restrictions on technical work in a broadcast station? 17422. 17423. 1st phone 17424. 2nd phone 17425. 3rd phone 17426. 4th phone 17427. 17428. What classes of operators are restricted on technical work in a broadcast station? 17429. 17430. 3rd phone 17431. 2nd phone 17432. 4th phone 17433. 2nd and 3rd phone 17434. 17435. If improper transmitter indications are given at the remote-control point, what should be done? 17436. 17437. First phone operator to transmitter 17438. Second phone operator to transmitter 17439. Third phone operator to transmitter 17440. Fourth phone to transmitter 17441. 17442. How often must IDs be made in a broadcast station? 17443. 17444. Quarter of an hour 17445. Half an hour 17446. On the hour 17447. On the day 17448. 17449. Where must station license be posted? 17450. 17451. Tower 17452. Modulators 17453. Transmitter 17454. Receiver 17455. 17456. Where operator licenses must be posted? 17457. 17458. Operating desk 17459. Operating position 17460. Operating console 17461. Anywhere 17462. 17463. What device is usually used today to measure the frequency of a broadcast station? 17464. 17465. Multivibrators 17466. Counter 17467. Ripper 17468. Wave meter 17469. 17470. What does EBS stand for? 17471. 17472. Electronic Broadcast System 17473. Emergency Broadcast System 17474. Electronic Base Station 17475. Emergency Base Station 17476. 17477. How often must EBS tests be made? 17478. 17479. Weekly 17480. Daily 17481. Monthly 17482. Yearly 17483. 17484. What must non-EBS station have? 17485. 17486. EBS signal monitor 17487. EAN signal monitor 17488. EAT signal monitor 17489. CPCS signal monitor 17490. 17491. What stylus material is used in broadcast station? 17492. 17493. Ruby 17494. Gamet 17495. Emerald 17496. Diamond 17497. 17498. What advantage is there to having heavy turntables? 17499. 17500. Constant speed 17501. Less vibration 17502. Rumble 17503. All of these 17504. 17505. What is the width of recording tapes? 17506. 17507. 0.5 inch 17508. 0.75 inch 17509. 0.125 inch 17510. 1 inch 17511. 17512. What frequency is used to erase tapes? 17513. 17514. Supersonic 17515. Subsonic 17516. Ultrasonic 17517. Infrasonic 17518. 17519. What tape speed produces highest fidelity of audio? 17520. 17521. 20 in/sec 17522. 15 in/sec 17523. 10 in/sec 17524. 5 in /sec 17525. 17526. What should be used to clean recording heads? 17527. 17528. Methanol 17529. Ethyl Alcohol 17530. Isopropyl alcohol 17531. Rubbing alcohol 17532. 17533. What impedance is usually used with broadcast microphones? 17534. 17535. All of these 17536. 150 ohms 17537. 250 ohms 17538. 600 ohms 17539. 17540. In what log is antenna-light information entered? 17541. 17542. Maintenance log 17543. Program log 17544. Operating log 17545. Logging log 17546. 17547. What was the name of the first TV camera tube? 17548. 17549. Vidicon 17550. Iconoscope 17551. Image orthicon 17552. Kinescope 17553. 17554. Which camera tube requires electron multipliers? 17555. 17556. Vidicon 17557. Iconoscope 17558. Image orthicon 17559. Kinescope 17560. 17561. Which is used in closed-circuit TV? 17562. 17563. Vidicon 17564. Iconoscope 17565. Image orthicon 17566. Kinescope 17567. 17568. What is the waveform of the sweep voltages? 17569. 17570. Trapezoidal 17571. Sawtooth 17572. Trigger 17573. Square 17574. 17575. If the pulse peak is 100% modulation, what is the blanking level? 17576. 17577. 25% 17578. 50% 17579. 65% 17580. 75% 17581. 17582. What device allows one camera to accept pictures from three or more projectors? 17583. 17584. Film multipliers 17585. Film demultiplexers 17586. Film multiplexers 17587. Film acceptor 17588. 17589. What is the order of scanning four successive motion-picture frames for TV? 17590. 17591. 3,2,3,2 17592. 2,3,2,3 17593. 2,2,3,3 17594. 3,3,2,2 17595. 17596. From the low-frequency end of a channel, what is the visual carrier frequency? 17597. 17598. 3.58 MHz 17599. 0.25 MHz 17600. 1.25 MHz 17601. 4.5 MHz 17602. 17603. The circuits make up the front end of a TV receiver, except: 17604. 17605. RF 17606. Mixer 17607. IF 17608. Oscillator 17609. 17610. What is the impedance at the antenna input terminals of a TV receiver? 17611. 17612. 300 ohms 17613. 150 ohms 17614. 50 ohms 17615. 100 ohms 17616. 17617. Why are triodes and MOSFETs best for TV RF amplifiers? 17618. 17619. High power 17620. Efficiency 17621. Low noise 17622. High gain 17623. 17624. In what circuit configuration are triodes and MOSFETs used? 17625. 17626. Cascade 17627. Darlington 17628. Cascade 17629. Shunt 17630. 17631. The signal might a video amplifier amplify? 17632. 17633. Aural IF 17634. Video 17635. Blanking 17636. Any of these 17637. 17638. When coupling from a sync separator, what is used to obtain the horizontal sync pulses? 17639. Integrator 17640. Corrector 17641. Differentiator 17642. Separator 17643. 17644. When coupling from a sync separator, what is used to obtain the vertical sync pulses? 17645. 17646. Integrator 17647. Corrector 17648. Differentiator 17649. Separator 17650. 17651. The type of active device used in horizontal output stages, except:? 17652. 17653. Vacuum tube 17654. FET 17655. BJT 17656. SCR 17657. 17658. What should be produced by weak blue, weak green, and weak red signals on a color CRT? 17659. 17660. White 17661. Shade 17662. Gray 17663. Off white 17664. 17665. How many such mirrors are required in a color TV camera? 17666. 17667. One 17668. Two 17669. Three 17670. Four 17671. 17672. What is the combining circuit called in TV? 17673. 17674. Combiner 17675. Multiplexer 17676. Integrator 17677. Mixer 17678. 17679. What is the letter symbol for the luminance signal? 17680. 17681. R 17682. Q 17683. I 17684. Y 17685. 17686. What is the total R + G + B for a Y signal? 17687. 17688. 0 17689. 1 17690. 2 17691. 1.5 17692. 17693. If a white scene is picked up what is the Y value? 17694. 17695. 1 17696. 2 17697. 0 17698. 2.5 17699. 17700. If a black scene is being picked up, what is the Y value? 17701. 17702. One 17703. 0.5 17704. Zero 17705. 1.5 17706. 17707. What circuit does a color killer kill? 17708. 17709. Bandstop filter 17710. High-pass filter 17711. Low-pass filter 17712. Bandpass filter 17713. 17714. If the blue dot is always at the bottom of a triad, what position must the blue gun always have? 17715. 17716. Top 17717. Left side 17718. Right aside 17719. Center 17720. 17721. How many cathodes in a shadow-mask picture tube? 17722. 17723. 1 17724. 2 17725. 3 17726. 4 17727. 17728. How many guns in a shadow mask picture tube? 17729. 17730. 1 17731. 2 17732. 3 17733. 4 17734. 17735. 17736. 17737. 17738. 17739. 17740. 17741. 17742. 17743. 17744. 17745. 17746. 17747. 17748. 17749. 17750. 17751. 17752. 17753. 17754. 17755. 17756. 17757. 17758. 17759. 17760. 17761. 17762. 17763. 17764. 17765. 17766. 17767. 17768. 17769. MULTIPLE CHOICE QUESTIONS IN 17770. TRANSMISSION LINES 17771. Electronics Systems and Technologies 17772. By 17773. Melvin C. Arceo 17774. 17775. 17776. 17777. 17778. 17779. 17780. 17781. 17782. 17783. 17784. 17785. 17786. 17787. 17788. 17789. 17790. 17791. 17792. ENCODED BY: 17793. ANDRADE, Caroline T. 17794. Category of media with some form of conductor that provides a conduit in which electromagnetic signals are contained. 17795. 17796. Guided 17797. Balanced 17798. Unguided 17799. Unbalanced 17800. 17801. The conductive connections between elements which carry signals. 17802. 17803. Transmission Lines 17804. Antenna 17805. Frequency allocations 17806. Load 17807. 17808. Calculate the characteristic impedance for a line that exhibits an inductance of 4 nH/m and 1.5pF/m 17809. 17810. 36.6 ohms 17811. 51.6 ohms 17812. 22 ohms 17813. 24.5 ohms 17814. 17815. Category of media which are wireless 17816. 17817. Guided 17818. Balanced 17819. Unguided 17820. Unbalanced 17821. 17822. It is a medium or any physical facility used to propagate electromagnetic signals between two locations in a communications system. 17823. 17824. Transmission medium 17825. Channel allocation 17826. Frequency allocation 17827. Any of these 17828. 17829. It is a metallic conductor system used to transfer electrical energy from one point to another using electrical current flow. 17830. Transmitter 17831. Multiplexers 17832. Receiver 17833. Transmission line 17834. 17835. A kind of wave where the displacement is in the direction of propagation. 17836. 17837. Transverse 17838. Longitudinal 17839. Reverse 17840. Perpendicular 17841. 17842. Calculate the capacitance per meter of a 50-ohm load cable that has an inductance of 55 nH/m. 17843. 17844. 13 pF 17845. 18 pF 17846. 20 pF 17847. 22 pF 17848. 17849. The desirable SWR on a transmission line is 17850. 17851. 0 17852. 1 17853. 2 17854. Infinity 17855. 17856. A kind of wave where the direction is displacement is perpendicular to the direction of propagation. 17857. 17858. Transverse 17859. Longitudinal 17860. Reverse 17861. Perpendicular 17862. 17863. A short-circuited half-wavelength line acts like a 17864. 17865. Parallel resonant circuit 17866. Series Resonant Circuit 17867. Oscillator 17868. LC circuit 17869. 17870. Electromagnetic waves that travel along a transmission line from the source to the load. 17871. 17872. Reverse waves 17873. Transverse waves 17874. Incident waves 17875. Longitudinal waves 17876. 17877. Electromagnetic waves that travel from the load back toward the source. 17878. 17879. Incident waves 17880. Transverse waves 17881. Forward waves 17882. Reflected waves 17883. 17884. Sound travels approximately 17885. 17886. 2200 feet per second 17887. 1100 feet per second 17888. 550 feet per second 17889. 600 feet per second 17890. 17891. Determine the surge impedance for a parallel wire, air dielectric with a ratio of the spacing between conductors and the diameter of 3 17892. 17893. 250 ohms 17894. 210 ohms 17895. 180 ohms 17896. 215 ohms 17897. 17898. The rate at which the periodic wave repeats 17899. 17900. Wavelength 17901. Amplitude 17902. Period 17903. Frequency 17904. 17905. The distance of one cycle occurring in space 17906. 17907. Wavelength 17908. Amplitudes 17909. Period 17910. Frequency 17911. 17912. Classification of transmission line where both conductors carry current; one conductor carries the signal, the other conductor is the return path 17913. 17914. Differential transmission lines 17915. Unbalanced lines 17916. Coaxial cables 17917. Balun 17918. 17919. A shorted half-wave line at the operating frequency acts like 17920. 17921. Capacitor 17922. Inductor 17923. Series resonant circuit 17924. Parallel resonant circuit 17925. 17926. What is the characteristic impedance of a coaxial line, air dielectric with a ratio of the diameter of the outer and inner conductor equal to 1.5? 17927. 17928. 24.3 ohms 17929. 25.6 ohms 17930. 13.2 ohms 17931. 18 ohms 17932. 17933. Currents that flow in opposite direction in a balanced wire pair is called 17934. 17935. Longitudinal currents 17936. Reverse circuit currents 17937. Transverse circuit currents 17938. Metallic circuit currents 17939. 17940. Currents that flow in same direction in a balanced wire pair is called 17941. 17942. Longitudinal currents 17943. Reverse circuit currents 17944. Transverse circuit currents 17945. In-phase currents 17946. 17947. A circuit device used to connect a balanced transmission line to an unbalanced load 17948. 17949. Slotted lines 17950. Stub 17951. Balun 17952. Quarterwave lines 17953. 17954. The most common type of balun used in relatively high frequency 17955. 17956. Narrowband 17957. Choke 17958. Sleeve 17959. All of these 17960. 17961. A pattern of voltage and current variations along the transmission line not terminated in its characteristic impedance is called 17962. 17963. An electric fluid 17964. Radio waves 17965. Standing waves 17966. A magnetic field 17967. 17968. A type of parallel-conductor transmission lines consists of simply of two parallel wires, closely-spaced and separated by air. 17969. 17970. Twisted pair 17971. Open-wire lines 17972. Coaxial cables 17973. Twin pair 17974. 17975. A type of parallel-conductor transmission lines which is essentially the same as open-wire transmission line except that the spacers between the conductors are replaced with a continuous solid dielectric that ensures uniform spacing along the entire cable 17976. 17977. Twisted pair 17978. Open-wire lines 17979. Coaxial cables 17980. Twin lead 17981. 17982. What is the range of size of wires of a twisted pair? 17983. 17984. AWG 16 to AWG 26 17985. AWG 14 to AWG 25 17986. AWG 10 to AWG 20 17987. AWG 12 to AWG 28 17988. 17989. What is the characteristic impedance of a coaxial line, polyethylene dielectric with the ratio of the diameter of the outer and the inner conductor of 2.5? 17990. 17991. 43.5 ohms 17992. 23.4 ohms 17993. 36.2 ohms 17994. 29.8 ohms 17995. 17996. In AWG, the higher the wire gauge ______17997. 17998. The higher the diameter and the lower the resistance 17999. The smaller the diameter and the higher the resistance 18000. The smaller the diameter and the higher the conductance 18001. The larger the diameter and the higher the resistance 18002. Type of twisted pair wire cable that consists of two copper wires where each wire is separately encapsulated in PVC insulation. 18003. 18004. Shielded twisted pair 18005. Twin lead 18006. Unshielded twisted pair 18007. Open wire frame 18008. 18009. A shorted quarter-wave line at the operating frequency acts like 18010. 18011. Series resonant circuit 18012. Parallel resonant circuit 18013. Capacitor 18014. Inductor 18015. 18016. The minimum number of twist for UTP is 18017. 18018. Two twist per foot 18019. Two twist per meter 18020. Three twist per foot 18021. Three twist per meter 18022. 18023. A delay line using RG-8A/U cable is to exhibit a 5-ns delay. Calculate the required length of the cable. 18024. 18025. 4.57 ft 18026. 1.23 ft 18027. 6.2 ft 18028. 3.4 ft 18029. 18030. An open-circuited quarter-wavelength line acts like a 18031. 18032. Parallel resonant circuit 18033. Series resonant circuit 18034. Oscillator 18035. LC circuit 18036. 18037. Level for category of UTP cable which is suitable only for voice grade telephone signals and very low-speed data applications 18038. 18039. Level 1 or Cat 1 18040. Level 3 or Cat 3 18041. Level 2 or Cat 2 18042. Cat 4 18043. 18044. An antenna is being fed by a properly terminated two-wire transmission line. The current in the line at the input end is 3A. The surge impedance of the line is 500 ohms. How much power is being supplied to the line? 18045. 18046. 3.1 kW 18047. 2.5 kW 18048. 1.6 kW 18049. 4.5 kW 18050. 18051. Level or Category of UTP cable which was developed for IEEE 802.5 token ring local area networks operating at a transmission rates of 4Mbps 18052. 18053. Level 1 or Cat 1 18054. Level 3 or Cat 3 18055. Level 2 or Cat 2 18056. Cat 4 18057. 18058. If the period of one complete cycle of a radio wave is 0.000001 s, what is the wavelength? 18059. 18060. 300 m 18061. 200 m 18062. 100 m 18063. 400 m 18064. 18065. If the two towers of a 950-kHz antenna are separated by 120 electrical degrees, what is the tower separation in feet? 18066. 18067. 231 ft 18068. 235 ft 18069. 176 ft 18070. 345 ft 18071. 18072. Category of UTP used for virtually any voice or data transmission rate up to 16 Mbps, has a minimum of 3 turns per inch. 18073. 18074. Category 5e 18075. Category 4 18076. Category 5 18077. Category 3 18078. 18079. The mismatch between the antenna and transmission line impedances cannot be corrected for by 18080. 18081. Using an LC matching network 18082. Adjusting antenna length 18083. Using a balun 18084. Adjusting the length of transmission line 18085. 18086. Category of UTP that was designed for data transmission rates up to 20 Mbps 18087. 18088. Category 5e 18089. Category 4 18090. Category 5 18091. Category 3 18092. 18093. Variation of CAT5 cables that are intended for data transmission rates up to 250 Mbps 18094. 18095. Category 5e 18096. Category 2 18097. Category 6 18098. Category 3 18099. 18100. A type of twisted-pair wherein its wires and dielectric are enclosed in a conductive metal sleeve called a foil. 18101. 18102. STP 18103. Twin lead 18104. UTP 18105. Unshielded Twin lead 18106. 18107. It is the name given to the area between the ceiling and the roof in a single-story building or between the ceiling and the floor of the next higher level in a multistory building. 18108. 18109. Attic 18110. Rooftop 18111. Plenum 18112. Ceiling 18113. 18114. It consists of center conductor surrounded by dielectric material, then a concentric shielding, and an environmental protection outer jacket. 18115. 18116. Twisted pair 18117. Coaxial cable 18118. Twin lead 18119. Open wire 18120. 18121. In a transmission line, it refers to the woven stranded mesh or braid that surround some types of coaxial cables 18122. 18123. Grounding 18124. Shielding 18125. Degaussing 18126. Any of these 18127. 18128. A coaxial cable with one layer of foil insulation and one layer of braided shielding. 18129. 18130. Backup shielding 18131. Temporary shielding 18132. Dual shielding 18133. Interference shielding 18134. 18135. At very high frequencies, transmission lines are used as 18136. 18137. Tuned circuits 18138. Antennas 18139. Insulators 18140. Resistors 18141. 18142. A coaxial cable with two layers of foil insulation and two layers of braided shielding. 18143. 18144. Quad shielding 18145. Double shielding 18146. Triple shielding 18147. Shielding 18148. 18149. A type of coaxial cable that has a tubular outer conductor surrounds the center conductor coaxially and the insulating material is air 18150. 18151. Rigid air coaxial cable 18152. Gas-filled coaxial cable 18153. Solid coaxial cable 18154. Flexible cable 18155. 18156. If the length of an open-circuited stub is less than quarter-wavelength but greater than 0, the stub behaves as 18157. 18158. Inductor 18159. Capacitor 18160. Resistor 18161. Complex 18162. 18163. Type of coaxial cable where the outer conductor is braided, flexible, and coaxial to the center conductor. 18164. 18165. Gas-filled coaxial cable 18166. Rigid air coaxial cable 18167. Solid flexible coaxial cable 18168. Flexible cable 18169. 18170. A 50-ohm coax is connected to a 73-ohm antenna. The SWR is 18171. 18172. 0.685 18173. 1 18174. 1.46 18175. 2.92 18176. 18177. Defined as the impedance seen looking at an infinitely long line or the impedance seen looking into a finite length of the line that is terminated in a purely resistive load with the resistance equal to the characteristic impedance of the line. 18178. 18179. Input impedance 18180. Surge impedance 18181. Output impedance 18182. Circuit impedance 18183. 18184. Determine the characteristic impedance for an air dielectric two-wire parallel transmission line with a D/r ratio of 12.22 18185. 18186. 150 ohms 18187. 120 ohms 18188. 75 ohms 18189. 300 ohms 18190. 18191. Determine the characteristic impedance for an RG-59A coaxial cable with the following specifications: d=0.025 inches, D=0.15 inches, and dielectric constant of 2.23 18192. 18193. 120 ohms 18194. 72 ohms 18195. 150 ohms 18196. 75 ohms 18197. 18198. Determine the characteristic impedance for an RG-59A coaxial cable with the following specifications: L=0.118 uH/ft and C=21 pF/ft 18199. 18200. 150 ohms 18201. 72 ohms 18202. 75 ohms 18203. 100 ohms 18204. 18205. It is used to express the attenuation or signal loss and the phase shift per unit length of the transmission line. 18206. 18207. Propagation coefficient 18208. Propagation constant 18209. Propagation factor 18210. Any of these 18211. 18212. For matched condition, what is the relationship of load and characteristic impedance? 18213. 18214. Greater than 18215. Less than 18216. Equal 18217. Impossible to say 18218. 18219. 18220. It is defined simply as the ratio of the actual velocity of propagation of an electromagnetic wave through a given medium to the velocity of propagation through a vacuum or free space. 18221. 18222. Velocity factor 18223. Velocity propagation 18224. Index of refraction 18225. Phase delay 18226. 18227. It is simply the permittivity of the material 18228. 18229. Permittivity 18230. Insulation constant 18231. Dielectric constant 18232. Resistivity 18233. 18234. For a given length of RG 8A/U coaxial cable with distributed capacitance of 96.6 pF/m, a distributed inductance of 241.56 nH/m, and a relative dielectric constant of 2.3, determine the velocity of propagation 18235. 18236. 1.07 x 10^8 m/s 18237. 2.3 x 10^7 m/s 18238. 3.28 x 10^8 m/s 18239. 2.07 x 10^8 m/s 18240. 18241. For a given length of RG 8A/U coaxial cable with distributed capacitance of 96.6 pF/m, a distributed inductance of 241.56 nH/m, and a relative dielectric constant of 2.3, determine the velocity factor 18242. 18243. 1.2 18244. 0.66 18245. 0.7 18246. 0.5 18247. 18248. If the length of an open-circuited stub is greater than quarter-wavelength but less than half-wavelength, the stub behaves as 18249. 18250. Inductor 18251. Capacitor 18252. Resistor 18253. Complex 18254. 18255. Delay line is a function of what two parameters? 18256. 18257. Resistance and capacitance 18258. Resistance and susceptance 18259. Inductance and resistance 18260. Inductance and capacitance 18261. 18262. How is the time delay calculated in a coaxial cables with a dielectric constant of 0.66? 18263. 18264. 0.56 sec 18265. 0.67 sec 18266. 0.45 sec 18267. 1.2 sec 18268. 18269. Three feet is one wavelength at a frequency of 18270. 18271. 100 MHz 18272. 164 MHz 18273. 300 MHz 18274. 328 MHz 18275. 18276. When current flows through a conductor, the loss introduced as a function of resistance and current is called ______18277. 18278. Inductance loss 18279. Conductor loss 18280. Voltage loss 18281. Skin effect 18282. 18283. For maximum absorption of power at the antenna, the relationship between the characteristic impedance of the line Zo and the load impedance ZL should be 18284. 18285. Zo = ZL 18286. Zo > ZL 18287. Zo < ZL 18288. Zo = 0 18289. 18290. The ratio of the AC resistance and the DC resistance 18291. 18292. Impedance ratio 18293. Susceptance ratio 18294. Resistance ratio 18295. Conductance ratio 18296. 18297. The difference in potential between two conductors of a metallic transmission line causes ______. 18298. 18299. Conductor loss 18300. Dielectric heating 18301. Radiation loss 18302. Corona 18303. 18304. If the length of a short-circuited stub is greater than quarter-wavelength but less than half-wavelength, the stub behaves as 18305. 18306. Inductor 18307. Capacitor 18308. Resistor 18309. Complex 18310. 18311. If the separation between the conductors in a metallic transmission line is an appreciable fraction of a wavelength, the electrostatic and electromagnetic fields that surround the conductor cause the line to act as if it were an antenna and transfer energy to any nearby material. This energy radiated is called ______. 18312. 18313. Radiation loss 18314. Power loss 18315. Coupling loss 18316. Corona 18317. 18318. The minimum voltage along a transmission line is 260 V, while the maximum is 390 V. The SWR is 18319. 18320. 0.67 18321. 1.0 18322. 1.2 18323. 1.5 18324. 18325. It occurs whenever a connection is made to or from a transmission line or when two sections of transmission line are connected together 18326. 18327. Power loss 18328. Coupling loss 18329. Radiation loss 18330. Resistance loss 18331. 18332. Which of the following is not a common transmission line impedance? 18333. 18334. 50 ohms 18335. 75 ohms 18336. 120 ohms 18337. 300 ohms 18338. 18339. It is a luminous discharge that occurs between the two conductors of a transmission line when the difference in potential between them exceeds the breakdown voltage of a dielectric insulator. 18340. 18341. Resistance loss 18342. Corona 18343. Radiation loss 18344. Power loss 18345. 18346. Voltage that propagates down the load 18347. 18348. Reflected voltage 18349. Standing wave ratio 18350. Incident voltage 18351. Reflection voltage 18352. 18353. Voltage that propagates from the load towards the source 18354. 18355. Reflected voltage 18356. Standing wave ratio 18357. Reflection coefficient 18358. Incident voltage 18359. 18360. A transmission line with no reflected power 18361. 18362. Flat 18363. Resistive 18364. Non resonant line 18365. Any of these 18366. 18367. It is a vector quantity that represents the ratio of reflected voltage to incident voltage or the reflected current and the incident current 18368. 18369. Reflection coefficient 18370. Reactive load diagram 18371. Standing wave ratio 18372. Traveling waves 18373. 18374. With a mismatched line, two electromagnetic waves traveling in opposite direction, present on the line on the same time. 18375. 18376. Standing wave ratio 18377. Reflection coefficient 18378. Standing waves 18379. Traveling waves 18380. 18381. The two traveling waves sets up an interference pattern called ______. 18382. 18383. Standing wave ratio 18384. Reflection coefficient 18385. Standing waves 18386. Traveling waves 18387. 18388. It is defined as the ratio of the maximum voltage to the minimum voltage or the maximum current to the minimum current of a standing wave in a transmission line. 18389. 18390. Standing wave ratio 18391. Normalized impedance 18392. Reflection coefficient 18393. Any of these 18394. 18395. For a transmission line with an incident voltage of 5V and a reflected voltage of 3V, determine the reflection coefficient. 18396. 18397. 0.4 18398. 0.6 18399. 0.5 18400. 0.7 18401. 18402. A ratio expressing the percentage of incident voltage reflected on a transmission line is known as the 18403. 18404. Velocity factor 18405. Standing wave ratio 18406. Reflection coefficient 18407. Line efficiency 18408. 18409. There is an impedance inversion in every ______. 18410. 18411. Half wavelength 18412. Quarter wavelength 18413. Full wavelength 18414. Three-eights of a wavelength 18415. 18416. The characteristic impedance of a transmission line does not depend upon its 18417. 18418. Length 18419. Conductor diameter 18420. Conductor spacing 18421. None of these 18422. 18423. ______are used to match transmission lines to purely resistive loads whose resistance is not equal to the characteristic impedance of the line. 18424. 18425. Stub 18426. Slotted lines 18427. Quarter-wavelength transformer 18428. Short circuited lines 18429. 18430. To match a transmission line with a reactive load ______18431. 18432. Use stub matching 18433. Use a slotted line 18434. Used a Q-section 18435. Use an open circuited lines 18436. 18437. A technique that can be used to locate an impairment in metallic cable 18438. 18439. TDR 18440. Wattmeter 18441. Voltmeter 18442. SWR meter 18443. 18444. A pulse is transmitted down a cable that has a velocity of propagation of 0.8c. The reflected signal is received 1us later. How far down the cable is the impairment? 18445. 18446. 240 m 18447. 15 m 18448. 60 m 18449. 120 m 18450. 18451. Using TDR, a transmission line impairment is located 3000m from the source. For a velocity propagation of 0.9c, determine the time elapsed from the beginning of the pulse to the reception of the echo 18452. 18453. 11.11 us 18454. 10.12 us 18455. 22.22 us 18456. 21.14 us 18457. 18458. A flat conductor separated from a ground plane by an insulating dielectric material 18459. 18460. Stripline 18461. Waveguide 18462. Microstrip 18463. Coaxial cable 18464. 18465. A flat conductor sandwich between two ground planes. 18466. 18467. Stripline 18468. Waveguide 18469. Microstrip 18470. Coaxial cable 18471. 18472. Indicate the false statement. The SWR on a transmission line is infinity; the line is terminated in 18473. 18474. A short circuit 18475. A complex impedance 18476. An open circuit 18477. A pure reactance 18478. 18479. The most commonly used transmission line is a 18480. 18481. Two-wire balance line 18482. Singe wire 18483. Three-wire line 18484. Coax 18485. 18486. A short-circuited half-wavelength line acts like a 18487. 18488. Parallel resonant circuit 18489. Series resonant circuit 18490. Oscillator 18491. LC circuit 18492. 18493. A (75-j50)-ohm is connected to a coaxial transmission line of Zo = 75 ohms, at 10 GHz. The best method of matching consists of connecting 18494. 18495. A short-circuited stub at the load 18496. An inductive at the load 18497. A capacitance at some specific distance from the load 18498. A short-circuited stub at some specific distance from the load 18499. 18500. The velocity factor of a transmission line 18501. 18502. Depends on the dielectric constant of the material used 18503. Increases in velocity along the transmission line 18504. Is governed by the skin effect 18505. Is higher for a solid dielectric than for air. 18506. 18507. Impedance inversion may be obtained with 18508. 18509. A short-circuited stub 18510. An open-circuited stub 18511. A quarter-wave line 18512. A half-wave line 18513. 18514. The most desirable reflection coefficient is 18515. 18516. 0 18517. 0.5 18518. 1 18519. Infinity 18520. 18521. Short circuited stubs are preferred to open-circuited stub because the latter are 18522. 18523. More difficult to make and connect 18524. Made of a transmission line with different characteristic impedance 18525. Liable to radiate 18526. Incapable of giving a full range of reactance 18527. 18528. For transmission-line load matching over a range of frequencies, it is best to use a 18529. 18530. Balun 18531. Broadband directional coupler 18532. Double stub 18533. Single stub of adjustable position 18534. 18535. The main disadvantage of the two-hole directional coupler is 18536. 18537. Low directional coupling 18538. Poor directivity 18539. High SWR 18540. Narrow bandwidth 18541. 18542. To couple a coaxial line to a parallel-wire line, it is best to use a 18543. 18544. Slotted line 18545. Balun 18546. Directional coupler 18547. Quarter-wave transformer 18548. 18549. A short-circuited quarter-wavelength line acts like a 18550. 18551. Parallel resonant circuit 18552. Series resonant circuit 18553. Oscillator 18554. LC circuit 18555. 18556. If the length of a short-circuited stub is less than a quarter-wavelength but greater than 0, the stub behaves as 18557. 18558. Inductor 18559. Capacitor 18560. Resistor 18561. Complex 18562. 18563. The depth of penetration of current density resulting from skin effect 18564. 18565. Skin depth 18566. Wire depth 18567. Line depth 18568. Medium depth 18569. 18570. Transmission line must be matched to the load to 18571. 18572. Transfer maximum voltage to the load 18573. Transfer maximum current to the load 18574. Reduce the load current 18575. Transfer maximum power to the load 18576. 18577. Referred to the dielectric constant of a transmission line material 18578. 18579. Inductance and capacitance 18580. Velocity factor 18581. Characteristic impedance 18582. Propagation velocity 18583. 18584. A transmission line containing of two conductors that have equal resistance per unit length 18585. 18586. Unbalanced line 18587. Open-wire line 18588. Balanced line 18589. Coaxial cable 18590. 18591. Which of the following determines the characteristics of a transmission line? 18592. 18593. Inductance 18594. Capacitance 18595. Physical dimension 18596. Length 18597. 18598. Category of UTP that was designed for data transmission rates up to 20 Mbps 18599. 18600. Category 5e 18601. Category 4 18602. Category 5 18603. Category 3 18604. 18605. Level 2 or category 2 UTP cables comply with IBM’s ______specification. 18606. 18607. Type 1 18608. Type 3 18609. Type 2 18610. Type 4 18611. 18612. Level 3 or Category 3 UTP cables should have at least ____ twist per inch. 18613. 18614. 1 18615. 2 18616. 3 18617. 4 18618. 18619. Which of the following is NOT a color code for Category 5 UTP? 18620. 18621. Blue/white stripe and blue 18622. Orange/white stripe and orange 18623. Red/white stripe and red 18624. Brown/white stripe and brown 18625. 18626. Shielded-screen twisted-pair cable or SSTP is also known as ______. 18627. 18628. Cat 5e 18629. Cat 7 18630. Cat 6 18631. Cat 8 18632. 18633. An open-circuited transmission line quarter wavelength long is equivalent to 18634. 18635. Parallel resonant circuit 18636. Series resonant circuit 18637. Inductive 18638. Capacitive 18639. 18640. A short-circuited transmission line more than quarter-wavelength long but shorter than half wavelength is equivalent to ______. 18641. 18642. Series resonant circuit 18643. Inductive 18644. Capacitive 18645. Parallel resonant circuit 18646. 18647. A short-circuited transmission line less than quarter-wavelength long. 18648. 18649. Inductive 18650. Capacitive 18651. Parallel resonant circuit 18652. Series resonant circuit 18653. 18654. The quarter-wavelength transformer line acts as a transformer with a 1:1 turns ratio when the load resistance is with what relationship with the characteristic impedance of the quarter-wavelength transformer? 18655. 18656. Equal 18657. Less than 18658. Greater than 18659. None of these 18660. 18661. The characteristic impedance of a microstrip is equal to _____ ohms. 18662. 18663. 50 to 200 18664. 25 to 50 18665. 100 to 200 18666. 50 to 75 18667. 18668. The quarter-wavelength transformer line acts as a step down transformer when the load resistance is with what relationship with the characteristic impedance of the quarter- wavelength transformer? 18669. 18670. Equal 18671. Less than 18672. Greater than 18673. None of these 18674. 18675. 18676. The typical value of the velocity factor of an open-wire transmission line is 18677. 18678. 0.8 18679. 0.7 18680. 0.6 18681. 0.9 18682. 18683. If a transmission line is not terminated in its characteristic impedance, ______will develop along the line. 18684. 18685. Traveling waves 18686. Standing waves 18687. Surge impedance 18688. Infinite impedance 18689. 18690. If a load and a line have mismatched impedances, power not absorbed by the load will be _____. 18691. 18692. Absorbed 18693. Rejected 18694. Reflected 18695. Removed 18696. 18697. 18698. 18699. 18700. 18701. 18702. 18703. 18704. 18705. 18706. 18707. 18708. 18709. 18710. 18711. 18712. 18713. 18714. MULTIPLE CHOICE QUESTIONS IN 18715. INTRODUCTION TO COMMUNICATIONS 18716. Electronics Systems and Technologies 18717. By 18718. Melvin C. Arceo

18719.

18720.

18721. 18722. 18723. 18724. 18725. 18726. ENCODED BY: 18727. GARCIA, Virginia Nonna H. 18728. It is the transmission, reception, and processing of information between two or more locations using electronic circuits. 18729. Electronic communications 18730. Electronic transfer 18731. Electronic mode 18732. Electronic codes 18733. 18734. The noise produced by a resistor is to be amplified by a noiseless amplifier having a voltage gain of 75 and a bandwidth of 100 kHz. A sensitive meter at the output reads 240 microvolts rms. Assuming operation of 37 degrees, calculate the resistor’s resistance. 18735. 4 kilo ohms 18736. 5 kilo ohms 18737. 6 kilo ohms 18738. 7 kilo ohms 18739. 18740. The first electronic communications system was develop in what century? 18741. 17th 18742. 19th 18743. 18th 18744. 20th 18745. 18746. Who was the first to successfully transmit wireless radio signals through Earth’s atmosphere? 18747. Samuel Morse 18748. Howard Armstrong 18749. Lee DeForest 18750. Guglielmo Marconi 18751. 18752. Who invented frequency modulation? 18753. Guglielmo Marconi 18754. Thomas Watson 18755. Alexander Graham Bell 18756. Howard Armstrong 18757. 18758. A component of the electronic communication system that provides a means of transporting signals from a transmitter to a receiver. 18759. Information 18760. modulator 18761. medium 18762. transmitter 18763. 18764. Calculate the noise power outputs of a 1 kilo ohm resistor at 27 degrees C over a 100-kHz bandwidth. 18765. 4.14 fW 18766. 0.414 fW 18767. 14.1 fW 18768. 141 fW 18769. 18770. ______is a collection of electronic devices and circuits that accepts the transmitted signals from the transmission medium and converts them back to their original form. 18771. channel 18772. receiver 18773. transmitter 18774. antenna 18775. 18776. A signal that carries the information through the system. 18777. information 18778. modulating signal 18779. intelligence 18780. carrier 18781. 18782. A signal that modulates a high-frequency signal or carrier in order to transfer information from one location to another 18783. intelligence 18784. modulated signal 18785. carrier 18786. intelligence or modulated signal 18787. 18788. Fourier series shows that a sawtooth wave consists of the following except 18789. fundamental and subharmonic sine waves 18790. a fundamental sine wave and an infinite number of harmonics 18791. fundamental and harmonic sine waves whose amplitude decreases with the harmonic number 18792. sinusoidal voltages, some of which are small enough to ignore in practice 18793. 18794. Determine the noise current for a diode with a forward bias of 1mA over a 1 MHz bandwidth. 18795. 19.8 nA 18796. 17.9 nA 18797. 12.3 nA 18798. 15 nA 18799. 18800. The process of changing one or more properties of the carrier in proportion with the information signal? 18801. demodulation 18802. transmission 18803. modulation 18804. reception 18805. 18806. A system where digital pulses are transferred between two points in a communication system. 18807. digital transmission 18808. analog transmission 18809. digital radio 18810. analog communications system 18811. 18812. It is the transmittal of digitally modulated analog carriers between two or more points in a communication system. 18813. analog transmission 18814. digital radio 18815. digital communications 18816. digital reception 18817. 18818. Type of modulation where the carrier amplitude is varied proportional to the information signal. 18819. AM 18820. PM 18821. FM 18822. Pulse modulation 18823. 18824. In FM, the ______is varied proportional to the information signal. 18825. phase 18826. time 18827. amplitude 18828. frequency 18829. 18830. A circuit that performs modulation 18831. demodulator 18832. synthesizer 18833. modulator 18834. limiter 18835. 18836. Calculate the signal to noise ratio for a receiver output of 4V signal and 0.48V noise in dB 18837. 18.5 dB 18838. 69 dB 18839. 25.4 dB 18840. 9.25 dB 18841. 18842. Modulation used is to the following except 18843. reduce the bandwidth used 18844. separate differing transmission 18845. ensure that intelligence may be transmitted over long distance 18846. allow the use of practicable antennas 18847. 18848. It performs the reverse process of modulation and converts the modulated carrier back to the original information. 18849. oscillator 18850. demodulator 18851. synthesizer 18852. mixer 18853. 18854. Indicate the false statement. The reasons why modulation is necessary in electronic communications is because: 18855. It is extremely difficult to radiate low-frequency signals from antenna in the form of electromagnetic energy. 18856. Information signals often occupy the same frequency band and, if signals from two or more sources at the same time, they would interfere with each other. 18857. To reduce the size of the capacitors and inductors of the tuned circuit. 18858. To increase the size of the transmitting and receiving antenna. 18859. 18860. The process of converting a frequency or band of frequencies to another location in the total frequency spectrum is called: 18861. translation 18862. demodulation 18863. modulation 18864. oscillation 18865. 18866. An intricate part of electronic communication system because of its up-and-down- conversion functions as they are transported through a channel. 18867. oscillation 18868. modulation 18869. demodulation 18870. translation 18871. 18872. ______is simply the number of times a periodic motion occurs in a given unit of time 18873. frequency 18874. time 18875. period 18876. phase 18877. 18878. The difference between the highest and the lowest frequencies contained in the information. 18879. noise 18880. bandwidth 18881. interference 18882. frequency 18883. 18884. It is a highly theoretical study of the efficient use of bandwidth to propagate information through electronic communications systems. 18885. information capacity 18886. information bandwidth 18887. information theory 18888. information entropy 18889. It is the measure of how much information can be transferred through a communications system in a given period of time. 18890. information bandwidth 18891. information capacity 18892. information density 18893. information theory 18894. 18895. The law that states that the wider the bandwidth and the longer the time of transmission, the more information that can be conveyed through the system. 18896. Information theory 18897. Information density law 18898. Hartley’s law 18899. Information entropy law 18900. 18901. A circuit configuration that involves one wire for the signal and one for the reference or ground. 18902. 2-wire 18903. 4-wire 18904. 3-wire 18905. 1-wire 18906. 18907. A circuit configuration that involves two for signal and two for reference or ground. 18908. 2-wire 18909. 4-wire 18910. 3-wire 18911. 1-wire 18912. 18913. It is used to match impedances and provide isolation between the two directions of signal flow. 18914. 2-wire 18915. hybrid set 18916. 4-wire transmission 18917. suppressors 18918. 18919. An interface circuit that is used when a two-wire circuit is connected to a four- wire circuit, as in long-distance telephone call. 18920. suppressors 18921. echo limiter 18922. codec 18923. terminating set 18924. 18925. An amplifier with a noise figure of 6dB has an input signal-to-noise ratio of 25dB. Calculate the output signal-to-noise ratio in dB. 18926. 31 dB 18927. 19 dB 18928. 20 dB 18929. 25 dB 18930. 18931. It is the process of combining two or more signals and is an essential process in electronic communications. 18932. oscillation 18933. mixing 18934. damping 18935. modulation 18936. 18937. ______occurs when two or more signals combine in a linear device, such as a passive network or a small-signal amplifier. 18938. non-linear mixing 18939. linear-phase filtering 18940. linear summing 18941. bandlimiting 18942. 18943. One of the following is not a useful quantity for comparing the noise performance of receivers: 18944. input noise voltage 18945. equivalent noise resistance 18946. noise temperature 18947. noise figure 18948. 18949. A single-stage amplifier has a 200-kHz bandwidth and a voltage gain of 100 at room temperature. Assume that the external noise is negligible and that a 1-mV signal is applied to the amplifier’s input. Calculate the output noise voltage if the amplifier has a 5-dB NF and the input noise is generated by a 2-kilo ohm resistor. 18950. 56.58 nV 18951. 458 uV 18952. 595.6 nV 18953. 356 uV 18954. 18955. In a communication system, which of the following reduces the information capacity of the system. 18956. linear-phase filtering 18957. mixing 18958. bandlimiting 18959. modulation 18960. 18961. ______occurs when two or more signals are combined in a non-linear device such as a diode or large-signal amplifier. 18962. modulation 18963. non-linear summing 18964. oscillation 18965. non-linear filtering 18966. Measuring physical condition of some remote location and transmitting this data for analysis is the process of 18967. Telemetry 18968. Instrumentation 18969. Modulation 18970. Multiplexing 18971. 18972. It is defined as any undesirable electrical energy that falls within the passband of the signal. 18973. interference 18974. noise 18975. splatter 18976. out-of-band signalling 18977. 18978. ______noise that is present regardless of whether there is a signal present or not. 18979. atmospheric noise 18980. correlated 18981. uncorrelated 18982. internal 18983. 18984. A three stage amplifier has an input stage with noise ratio of 5 and power gain of 50. Stages 2 and 3 have a noise ratio of 10 and power gain of 1000. Calculate the noise figure for the overall system. 18985. 4.55 dB 18986. 7.14 dB 18987. 6 dB 18988. 5.18 dB 18989. 18990. In communication system, noise is most likely to affect the signal 18991. at the transmitter 18992. in the channel 18993. in the information source 18994. at the information 18995. 18996. Which of the following is not true? 18997. HF mixers are generally noisier than HF amplifiers 18998. Impulse noise voltage is independent of bandwidth 18999. Thermal noise is independent of the frequency at which it is measured. 19000. Industrial noise is usually of the impulse type 19001. 19002. It is a type of noise that is generated outside the device of circuit. 19003. shot noise 19004. noise voltage 19005. thermal noise 19006. external noise 19007. ______noise is a naturally occurring electrical disturbances which is commonly called static electricity. 19008. Transit-time noise 19009. Extraterrestrial noise 19010. Solar noise 19011. Atmospheric noise 19012. 19013. What is the noise whose source is in a category different from that of the other three. 19014. solar noise 19015. cosmic noise 19016. atmospheric noise 19017. galactic noise 19018. 19019. A microwave antenna with an equivalent noise temperature of 25 K is coupled through a network with an equivalent noise temperature of 30 K to a microwave receiver with an equivalent noise temperature of 60 K referred to its input. Calculate the noise power at its input for a 2-MHz bandwidth. 19020. 3.15 fW 19021. 4.35 fW 19022. 2.12 fW 19023. 1.24 fW 19024. 19025. Which of the following is not another name of thermal agitation noise? 19026. White noise 19027. Pink noise 19028. Johnson noise 19029. Brown noise 19030. 19031. Any modification to a stream of carriers as they pass from the input to the output of a device produces an irregular, random variation is called ______noise. 19032. Transit-time noise 19033. Man-made noise 19034. Thermal noise 19035. Internal noise 19036. 19037. One of the following types of noise becomes of great importance at high frequencies. It is the 19038. shot noise 19039. random noise 19040. impulse noise 19041. transit-time noise 19042. 19043. The noise that was first observed in the anode current of a vacuum tube amplifier and was described mathematically by W. Schottky in 1918. 19044. Shot noise 19045. Transit-time noise 19046. External noise 19047. Thermal agitation noise 19048. 19049. Also known as black-body noise 19050. cosmic noise 19051. extraterrestrial noise 19052. solar noise 19053. man made noise 19054. 19055. Also known as deep-space noise 19056. solar noise 19057. cosmic noise 19058. extraterrestrial noise 19059. galactic noise 19060. 19061. ______noise is noise that is mutually related to the signal and cannot be present in a circuit unless there is an input signal input. 19062. solar noise 19063. uncorrelated noise 19064. correlated noise 19065. noise voltage 19066. 19067. The square of the thermal noise voltage generated by a resistor is proportional to 19068. its resistance 19069. its temperature 19070. Boltzmann’s constant 19071. The bandwidth over which it is measured 19072. 19073. It is a type of distortion that when unwanted harmonics of a signal are produced through a nonlinear amplification. 19074. intermodulation distortion 19075. buck-shot 19076. splatter 19077. harmonic distortion 19078. 19079. Which of the following is not used for communications 19080. X-rays 19081. Millimeter waves 19082. Infrared 19083. Microwaves 19084. 19085. ______are integer multiples of the original input signal. 19086. interference 19087. harmonic 19088. fundamental 19089. distortion 19090. A type of distortion that results from the generation of unwanted sum and difference frequencies when two or more signals are amplified in a linear device, such as a large-signal amplifier. 19091. harmonic distortion 19092. intermodulation distortion 19093. interference 19094. cross talk 19095. 19096. A form of noise that is characterized by its capability to disturb or distract. 19097. impulse noise 19098. man-made noise 19099. solar noise 19100. interference 19101. 19102. A type of noise that is characterized by high-amplitude peaks of short duration in the total noise spectrum. 19103. transit-time noise 19104. solar noise 19105. thermal noise 19106. impulse noise 19107. 19108. ______is a figure of merit used to indicate how much the signal-to-noise ratio deteriorates as a signal passes through a circuit or series of circuits. 19109. SINAD 19110. Q-factor 19111. Noise figure 19112. S/N ratio 19113. 19114. The value of resistor creating thermal noise is doubled. The noise power generated therefore 19115. halved 19116. quadrupled 19117. doubled 19118. unchanged 19119. 19120. Electromagnetic waves produced primarily by heat are called 19121. Infrared 19122. Microwaves 19123. Shortwaves 19124. X-ray 19125. 19126. Receiving electromagnetic emission from stars is called 19127. Astrology 19128. Optical astronomy 19129. Radio astronomy 19130. Space surveillance 19131. It is a collection of electronic components and circuits designed to convert the information into a signal suitable for transmission over a given communication medium. 19132. receiver 19133. medium 19134. transmitter 19135. mixer 19136. 19137. It is where the electronic signal is sent from one place to another. 19138. receiver 19139. transmitter 19140. source 19141. channel 19142. 19143. It is a broad general term applied to any form of wireless communication from one point to another. 19144. radio 19145. frequency 19146. signal 19147. spectrum 19148. 19149. Collection of electronic components and circuits that accept the transmitted message from the channel and convert it back into a form understandable by humans. 19150. receiver 19151. medium 19152. transmitter 19153. converter 19154. 19155. It is a random, undesirable, electric energy that enters a communications system via the communicating medium and interferes with the transmitted message. 19156. interference 19157. noise 19158. distortion 19159. fluctuations 19160. 19161. A system that transmits information about the physical status of the satellite including the position and temperature. 19162. telecommand 19163. telemovement 19164. television 19165. telemetry 19166. 19167. Regardless of whether information is analog or digital, these signals are referred to as ______. 19168. broadband 19169. composite 19170. baseband 19171. any of these 19172. 19173. Putting the original voice, video, or digital data directly into the medium is referred to as ______. 19174. baseband transmission 19175. composite transmission 19176. broadband transmission 19177. data transmission 19178. 19179. It is the process of having a baseband voice, video, or digital signal modify another, higher-frequency signal. 19180. mixing 19181. summing 19182. heterodyning 19183. modulation 19184. 19185. It is the process of transmitting two or more signals simultaneously over the same channel. 19186. modulation 19187. multiplexing 19188. summing 19189. demodulation 19190. 19191. The entire range of frequencies is referred to as ______. 19192. frequency spectrum 19193. signals spectrum 19194. electromagnetic spectrum 19195. radio spectrum 19196. 19197. What is the wavelength in meters, if the frequency is 10 MHz? 19198. 30 19199. 0.3 19200. 3 19201. 300 19202. 19203. Musical instruments makes sounds usually in what range? 19204. LF 19205. VLF 19206. VF 19207. HF 19208. 19209. Range of electromagnetic spectrum used in navy to communicate submarines 19210. VLF 19211. LF 19212. HF 19213. UHF 19214. Frequencies above 1 GHz range is called ______. 19215. milliwaves 19216. microwaves 19217. centiwaves 19218. hectowaves 19219. 19220. The range of long infrared is 19221. 0.01 mm to 1000 nm 19222. 0.01 mm to 700 nm 19223. 1000nm to 700 nm 19224. 0.4 um to 0.8 um 19225. 19226. A radiation that is generally associated with heat. 19227. ultraviolet 19228. visible light 19229. infrared 19230. EHF 19231. 19232. Infrared occupies approximately 19233. 0.01 mm to 1000nm 19234. 0.01 mm to 700 nm 19235. 1000nm to 700 nm 19236. 0.4 um to 0.8 um 19237. 19238. Light is a special type of electromagnetic radiation which has a wavelength range of 19239. 0.01 mm to 1000nm 19240. 0.01 mm to 700 nm 19241. 1000nm to 700 nm 19242. 0.4 um to 0.8 um 19243. 19244. The approximate frequency of a red 19245. 8000 Angstrom 19246. 800 Angstrom 19247. 4000 Angstrom 19248. 400 Angstrom 19249. 19250. It is the portion of electromagnetic spectrum occupied by the signal. 19251. spectrum 19252. composite 19253. bandwidth 19254. multiplexed 19255. 19256. It is the frequency range over which an information signal is transmitted or over which a receiver or other electronic equipment operate. 19257. composite 19258. bandwidth 19259. summed frequency 19260. signals 19261. 19262. The range of frequencies required to transmit the desired information. 19263. channel bandwidth 19264. information capacity 19265. information bandwidth 19266. channel capacity 19267. 19268. The first complete system of wireless communications was provided by 19269. Samuel Morse 19270. Guglielmo Marconi 19271. James Maxwell 19272. Heinrich Hertz 19273. 19274. Calculate the noise power at the input of a microwave receiver with an equivalent noise temperature of 45 K. It is fed from an antenna with a 35 K equivalent noise temperature and operates over a 5-MHz bandwidth. 19275. 3.56 fW 19276. 1.34 fW 19277. 2.98 fW 19278. 5.52 fW 19279. 19280. It is the process of putting information onto a high-frequency carrier for transmission. 19281. multiplexing 19282. modulation 19283. mixing 19284. heterodyning 19285. 19286. It is generally a device that converts energy from one form to another. 19287. transformer 19288. motor 19289. transducer 19290. generator 19291. 19292. Man-made noise occurs randomly at frequencies up to around 19293. 100 Hz 19294. 300 kHz 19295. 200 MHz 19296. 500 MHz 19297. 19298. What is the seventh harmonic of 360 kHz? 19299. 2520 kHz 19300. 46.08 MHz 19301. 3.6 x 10^12 Hz 19302. 1980 kHz 19303. Atmospheric noise is not a significant factor for frequencies exceeding about ______. 19304. 30 MHz 19305. 50 MHz 19306. 10 MHz 19307. 25 MHz 19308. 19309. Space noise contains less energy below 19310. 9 MHz 19311. 15 MHz 19312. 20 MHz 19313. 8 MHz 19314. 19315. The process of converting a frequency or band of frequencies to another location in the 19316. total frequency spectrum 19317. a. modulation 19318. b. detection 19319. c. frequency translation 19320. d. amplification 19321. 19322. 101.What is frequency range of EHF? 19323. a. 3 – 30 GHz 19324. b.30 – 300 GHz 19325. c. 30 – 300 MHz 19326. d. 300 – 3000 MHz 19327. 19328. Calculate the wavelength in free space corresponding to a frequency of AM radio 19329. broadcast band of 1 MHz 19330. a. 300 m 19331. b. 7.5 m 19332. c. 11.1 m 19333. d. 3.25 m 19334. 19335. When the input power is reduced in half at the output, the signal power is said to be 19336. reduced by: 19337. a. 2 dB 19338. b. 6 dB 19339. c. 4 dB 19340. d. 3 dB 19341. 19342. 104. A current change that is equal to twice its original value will correspond to a change of 19343. a. 3 dB 19344. b. 9 dB 19345. c. 10 dB 19346. d. 6 dB 19347. 19348. There are four networks in series. The first network has a gain of 15 dB, the second has 19349. a loss of 4 dB, the third gain of 35 dB, and the fourth a loss of 5 dB. The input of the first network is +3dBm. What is the output to the last network in mW. 19350. a. 15913.1 19351. b. 19922.9 19352. c. 25118.9 19353. d. 29523.6 19354. 19355. The PLL is often combined with ______circuits to produce multiple frequencies. 19356. a. Local oscillator 19357. b. Mixer 19358. c. RF amplifier 19359. d. AF amplifier 19360. 19361. Flicker noise may be completely ignored above about ______. 19362. a. 500 Hz 19363. b. 350 Hz 19364. c. 225 Hz 19365. d. 300 Hz 19366. 19367. Determine the noise figure for an equivalent noise temperature of 75 K. 19368. a. 1 dB 19369. b. 3 dB 19370. c. 2 dB 19371. d. 1.25 dB 19372. 19373. What is the other name for HF? 19374. a. microwaves 19375. b. short waves 19376. c. millimeter waves 19377. d. audio waves 19378. 19379. It is a resistive network that is used to introduce a fixed amount of attenuation between the source and a load. 19380. a. limiter 19381. b. clipper 19382. c. mixer 19383. d. attenuator 19384. 19385. A technique used in improving communication when a high peak-to-average power ratio of atmospheric noise occurs, the receiver is disabled during the duration of these burst. 19386. a. quieting 19387. b. noise blanking 19388. c. limiting 19389. d. mixing 19390. 19391. It is the ratio of the signal power level to noise power level 19392. a. noise figure 19393. b. signal-to-noise ratio 19394. c. SINAD 19395. d. noise improvement factor 19396. 19397. It is a figure of merit used to indicate how much the signal-to-noise ratio deteriorates as a signal passes through a circuit or series of circuits. 19398. a. Q-factor 19399. b. signal-to-noise ratio 19400. c. noise factor 19401. d. numerical aperture 19402. 19403. What is the major contributor of transistor noise? 19404. a. thermal agitation noise 19405. b. pink noise 19406. c. flicker noise 19407. d. shot noise 19408. 19409. Which of the following is not known as excess noise? 19410. a. pink noise 19411.b. 1/f noise 19412. c. flicker noise 19413. d. brown noise 19414. 19415. It is the relative measure of the desired signal power to the noise power 19416. a. noise factor 19417. b. signal-to-noise ratio 19418. c. noise figure 19419. d. noise improvement factor 19420. 19421. Which of the following is a desirable value of signal-to-noise ratio in dB? 19422. a. 0 19423. b. 100 19424. c. 1 19425. d. 50 19426. 19427. It is the range of frequency in which the upper frequency is double the lower frequency 19428. a. decade 19429. b. pentade 19430. c. octave 19431. d. none of these 19432. 19433. Which of the following noise figure is more desirable? 19434. a. 0 dB 19435. b. 100 dB 19436. c. 1 dB 19437. d. infinity 19438. 19439. The formula used to measure the total noise figure due to amplifiers in cascade is called ______. 19440. a. Johnson’s formula 19441. b. Shannon’s formula 19442. c. Hartley’s formula 19443. d. Friss’ formula 19444. 19445. It is defined as to fluctuate between two states or conditions. 19446. a. oscillate 19447. b. synchronization 19448. c. amplify 19449. d. signal generation 19450. 19451. An oscillator is ______when the changes in a waveform are continuous and repetitive and occurs in a periodic rate. 19452. a. locking 19453. b. one-shot 19454. c. triggered 19455. d. self-sustaining 19456. 19457. A free-running oscillator is also called ______. 19458. a. one-shot 19459. b. triggered 19460. c. locking 19461. d. self-sustaining 19462. 19463. Oscillators that are not self-sustaining are called ______. 19464. a. free-running 19465. b. feedback 19466. c. triggered 19467. d. regenerative 19468. 19469. An oscillator that is an amplifier with a feedback loop. 19470. a. signal generator 19471. b. feedback oscillator 19472. c. frequency synthesizer 19473. d. frequency synchronization circuit 19474. 19475. For a feedback circuit to sustain oscillation, the net voltage gain around the feedback loop must be unity or greater, and the net phase shift around the loop must be positive integer multiply of 360 degrees. 19476. a. Barkhausen criterion 19477. b. Butterworth criterion 19478. c. Flywheel effect 19479. d. Feedback criterion 19480. 19481. A circuit which comprises of a voltage amplifier with an open-loop voltage gain, a frequency-determining regenerative feedback path with a feedback ratio and either a summer or subtractor circuit. 19482. a. amplifier 19483. b. closed-loop 19484. c. power source 19485. d. open-loop 19486. 19487. It is the overall voltage gain of the complete circuit with the feedback loop closed and is always less than the open-loop voltage gain. 19488. a. feedback ratio 19489. b. closed-loop voltage gain 19490. c. open-loop current gain 19491. d. close-loop current gain 19492. 19493. It is the transfer function of the feedback network. 19494. a. feedback ratio 19495. b. closed-loop current gain 19496. c. open-loop voltage gain 19497. d. open-loop current gain 19498. 19499. It is an untuned RC shift oscillator that uses both positive and negative feedback. 19500. a. LC tank circuit 19501. b. Colpitts oscillators 19502. c. Hartley oscillators 19503. d. Wein-Bridge oscillators 19504. 19505. Its operation involves an exchange of energy between kinetic and potential. 19506. a. Wein-Bridge oscillators 19507. b. LC tank circuit 19508. c. Clapp oscillators 19509. d. Hartley oscillators 19510. 19511. It is the ability of an oscillator to remain at as fixed frequency and is of primary importance in a communications system 19512. a. oscillation 19513. b. synchronization 19514. c. frequency stability 19515. d. filtering 19516. 19517. It is a function of component aging and changes in the ambient temperature and humidity. 19518. a. short-term stability 19519. b. damping 19520. c. long-term stability 19521. d. filtering 19522. 19523. It is the study of the form, structure, properties and classifications of crystals 19524. a. Crystallography 19525. b. Stalactitomy 19526. c. Crystallomagraphy 19527. d. Stalagmitophy 19528. 19529. It deals with lattices, bonding and behaviour of splices of crystal material that have been cut at various angles with respect to the crystal’s axes. 19530. a. Crystallography 19531. b. Stalactitomy 19532. c. Crystallomagraphy 19533. d. Stalagmitophy 19534. 19535. It occurs when oscillating mechanical stresses applied across a crystal lattice structure generate electrical oscillations and vice-versa. 19536. a. crystal effect 19537. b. photoelectric effect 19538. c. piezoelectric effect 19539. d. solar effect 19540. 19541. Which of the following crystals is commonly used in microphones? 19542. a. Quartz 19543. b. Rochelle salt 19544. c. Tourmaline 19545. d. ADP 19546. 19547. Which of the following crystals is often used for frequency control in oscillators? 19548. a. EDT 19549. b. Synthetic quartz 19550. c. Tourmaline 19551. d. Rochelle salt 19552. 19553. An increase in temperature causes an increase in frequency and a decrease in temperature causes an increase in frequency. 19554. a. negative temperature coefficient 19555. b. positive temperature coefficient 19556. c. constant temperature coefficient 19557. d. temperature coefficient 19558. 19559. It is a specially constructed diode whose internal capacitance is enhanced when reverse biased, and by varying the reverse bias voltage, the capacitance of the diode can be adjusted. 19560. a. tunnel diode 19561. b. SAW 19562. c. backward diode 19563. d. varactor 19564. 19565. It is often used when describing varactor diode fabrication. 19566. a. graded junction 19567. b. reverse junction 19568. c. barrier junction 19569. d. capacitive junction 19570. 19571. It is an oscillator circuit that generates well-defined, stable waveforms that can be externally modulated or swept over a given frequency range. 19572. a. swept generator 19573. b. frequency synthesizer 19574. c. wave generator 19575. d. frequency synchronizer 19576. 19577. It is a free-running oscillator with a stable frequency of oscillation that depends on an external timing capacitance, timing resistance, and control voltage. 19578. a. multiplier 19579. b. monolithic controlled oscillator 19580. c. voltage-controlled oscillator 19581. d. phase-locked loop 19582. 19583. It is defined as the range of frequencies in vicinity of the VCO’s natural frequency over which the PLL can maintain lock with an input signal. 19584. a. capture range 19585. b. lock range 19586. c. bandwidth 19587. d. free-running frequency 19588. 19589. The voltage-controlled oscillator operates at a set frequency called 19590. a. free-running frequency 19591. b. capture range 19592. c. lock range 19593. d. bandwidth 19594. 19595. Free-running frequency is also known as ______. 19596. a. capture range 19597. b. lock range 19598. c. tracking range 19599. d. natural 19600. 19601. 147. Also known as lock range 19602. a. capture range 19603. b. free-running frequency 19604. c. natural frequency 19605. d. tracking range 19606. 19607. 148. It is defined as the band of frequencies in the vicinity of the natural frequency where the 19608. PLL can establish or acquire lock with an input signal. 19609. a. tracking range 19610. b. capture range 19611.c. lock range 19612. d. hold-in range 19613. 19614. 149. It is an oscillator with stable frequency of oscillation that depends on an external bias 19615. voltage. 19616. a. multiplier 19617. b. monolithic controlled oscillator 19618. c. voltage-controlled oscillator 19619. d. phase-locked loop 19620. 19621. 150. Also known as phase comparator 19622. a. phase detector 19623. b. phase-lock loop 19624. c. voltage controlled oscillator 19625. d. frequency synthesizer 19626. 19627. 151. It means to form an entity by combining parts or elements. 19628. a. oscillate 19629. b. integrate 19630. c. amplify 19631. d. synthesize 19632. 19633. 152. It is used to generate many output frequencies through the addition, subtraction, 19634. multiplication, and division of a smaller number of fixed frequency sources. 19635. a. power amplifier 19636. b. frequency synchronizer 19637. c. oscillator 19638. d. frequency synthesizer 19639. 19640. 153. A type of frequency synthesis in which multiple output frequencies are generated by mixing the outputs from two or more crystal- controlled frequency sources or by dividing 19641. or multiplying the output frequency form a single-crystal oscillator. 19642. a. direct frequency synthesis 19643. b. constant frequency synthesis 19644. c. indirect frequency synthesis 19645. d. multiple frequency synthesis 19646. 19647. 154. It is the minimum frequency separation between output frequencies for the synthesizer. 19648. a. dynamic range 19649. b. resolution 19650. c. octave 19651. d. decade 19652. 19653. 155. Zero beat is also known as ______. 19654. a. phase acquisition 19655. b. loop acquisition 19656. c. push-in acquisition 19657. d. frequency acquisition 19658. 19659. 156. Capture range is also known as ______. 19660. a. pull-in range 19661. b. lock range 19662. c. acquisition range 19663. d. hold-in range 19664. 19665. 157. Half of the lock range is equal to ______. 19666. a. capture range 19667. b. hold-in range 19668. c. pull-in range 19669. d. free-running frequency 19670. 19671. 158. The ______gain for a PLL is simply the product of the individual gains or transfer 19672. function for the loop. 19673. a. loop 19674. b. capture 19675. c. lock 19676. d. closed 19677. 19678. 159. Considered as the main source of an internal noise. 19679. a. Flicker 19680. b. Thermal agitation 19681. c. Device imperfection 19682. d. Temperature change 19683. 19684. 160. What is the first symbol of a radio signal emission having amplitude modulated main 19685. carrier? 19686. a. C 19687. b. B 19688. c. H 19689. d. A 19690. 19691. 161. The method of determining the bandwidth requirements for any processing system is 19692. referred to as: 19693. a. frequency spectrum 19694. b. frequency analysis 19695. c. spectral analysis 19696. d. bandwidth analysis 19697. 19698. 162. When two-equal frequencies are mixed together, the result is 19699. a. zero-bias 19700. b. zero-beat 19701. c. zero-modulation 19702. d. off-beat 19703. 19704. 163. Noise uniformly distributed over the voice frequency band is called ______noise. 19705. a. impulse 19706. b. quantizing 19707. c. intermodulation 19708. d. white 19709. 19710. 164. In psophometric noise weighting, one picowatt is equivalent to 800 Hz tone with a 19711. power of 19712. a. -90 dBm 19713. b. -85 dBm 19714. c. -65 dBm 19715. d. none of the above 19716. 19717. 165. What is the reference tone level for dBa? 19718. a. -90 dBm 19719. b. -82 dBm 19720. c. -67 dBm 19721. d. -85 dBm 19722. 19723. 166. What is the reference tone level for dBm? 19724. a. -90 dBm 19725. b. -82 dBm 19726. c. -67 dBm 19727. d. -85 dBm 19728. 19729. 167. At what power level does a 1 kHz tone causes zero interference (144 weighted)? 19730. a. 90 dB 19731. b. 90 dBm 19732. c. -90 dB 19733. d. -90 dBm 19734. 19735. 168. A tone of ______Hz causes more interference than do other frequencies, in a voice 19736. channel. 19737. a. 300 19738. b. 1000 19739. c. 3400 19740. d. 4000 19741. 169. A power of a standard test tone is normally ______. 19742. a. 0 mW 19743. b. 1 W 19744. c. 1 dB 19745. d. 1 mW 19746. 19747. 170. The standard test tone has a frequency of ______Hz. 19748. a. 1000 19749. b. 10 19750. c. 100 19751. d. none of these 19752. 19753. 171. In an analog voice frequency channel, the unwanted change in phase or frequency 19754. caused by modulation of another signal is; 19755. a. Intrinsic noise 19756. b. white noise 19757. c. intermodulation 19758. d. phase-jitter 19759. 19760. 172. The kind of noise that is caused by mismatched lines; 19761. a. echo noise 19762. b. impulse noise 19763. c. partition noise 19764. d. intermodulation noise 19765. 19766. 173. What is the reference tone level for random noise measurement, F1A weighted? 19767. a. -90 dBm 19768. b. -82 dBm 19769. c. -67 dBm 19770. d. -85 dBm 19771. 19772. 174. A ten times power change in a transmission system is equivalent to: 19773. a. 10 dB 19774. b. 100 dB 19775. c. 20 dB 19776. d. 10 dB 19777. 19778. 175. If the transmitter output power of 10 watts is doubled, the gain derived is about: 19779. a. 6 dB 19780. b. 4 dB 19781. c. 13 dB 19782. d. noise of the above 19783. 19784. 176. When the power ratio of the input to output is 1/100, the loss of the circuit, in dB, is 19785. a. 20 19786. b. -20 19787. c. -10 19788. d. 3 19789. 19790. 177. An antenna which has a power gain of 30 dB would mean it could increase the output of 19791. the transmitter by: 19792. a. 10,000 times 19793. b. 1,000 times 19794. c. 100 times 19795. d. 1 million times 19796. 19797. 178. In a double-tuned circuit, and peak output with ______coupling. 19798. a. under 19799. b. over 19800. c. optimum 19801. d. medium 19802. 19803. 179. The frequency band used by cellular telephones and cellular telephones and mobile 19804. communication services is ______. 19805. a. UHF 19806. b. EHF 19807. c. VHF 19808. d. VLF 19809. 19810. 180. The radio wavelength known as ______falls within the medium frequency range. 19811. a. centimetric 19812. b. decametric 19813. c. hectometric 19814. d. myriametric 19815. 19816. 181. In a double-tuned circuit, maximum bandwidth with ______coupling 19817. a. under 19818. b. over 19819. c. optimum 19820. d. critical 19821. 19822. 182. Decreasing the Q of a resonant circuit causes its bandwidth to ______. 19823. a. increase 19824. b. decrease 19825. c. become constant 19826. d. become narrow 19827. 19828. 183. Most impedance-matching networks are ______filters, so they eliminate harmonics. 19829. a. high-pass 19830. b. low-pass 19831. c. bandpass 19832. d. bandstop 19833. 184. ______are types of noise generated by equipments that produces sparks. 19834. a. equipment noise 19835. b. atmospheric noise 19836. c. space noise 19837. d. internal noise 19838. 19839. 185. A high-frequency noise occurs when the time taken by change carriers to cross a 19840. junction is comparable to the period of the signal 19841. a. pink noise 19842. b. transit-time noise 19843. c. white noise 19844. d. flicker noise 19845. 19846. 186. The electromagnetic spectrum is managed worldwide by the ______organization. 19847. a. FCC 19848. b. SI 19849. c. ANSI 19850. d. ITU 19851. 19852. 187. Unwanted mixer output signals are eliminated by a ______. 19853. a. filter 19854. b. multiplexer 19855. c. mixer 19856. d. amplifier 19857. 19858. 188. The bandwidth of a double-tuned transformer depends upon the degree of ______19859. between primary and secondary windings. 19860. a. mutual inductance 19861. b. coupling coefficient 19862. c. limiting factor 19863. d. filtering 19864. 19865. 189. In a double-tuned circuit, minimum bandwidth is obtained with ______coupling. 19866. a. under 19867. b. over 19868. c. optimum 19869. d. critical 19870. 19871. 190. A basic circuit of a frequency of a synthesizer is a ______. 19872. a. PLL 19873. b. LC oscillator 19874. c. Crystal oscillator 19875. d. RC oscillator 19876. 19877. 191. The output frequency of a synthesizer is changed by varying the ______of the 19878. divider between the VCO and the phase detector. 19879. a. Mixer output 19880. b. IF output 19881. c. Frequency division ratio 19882. d. Voltage division ratio 19883. 19884. 192. The PLL is often combined with ______circuits to produce multiple frequencies. 19885. a. Local oscillator 19886. b. Mixer 19887. c. RF amplifier 19888. d. AF amplifier 19889. 19890. 193. A crystal oscillator has superior ______over an LC oscillator. 19891. a. amplitude stability 19892. b. frequency stability 19893. c. phase stability 19894. d. voltage stability 19895. 19896. 194. If a parallel LC circuit is at resonance, increasing C will cause the current to ______19897. the applied voltage. 19898. a. lead 19899. b. lag 19900. c. lead-lag 19901. d. lag-lead 19902. 19903. 195. Information sent in the form of coded dots and dashes is called ______transmission. 19904. a. baudot 19905. b. continuous-wave 19906. c. digital 19907. d. any of these 19908. 19909. 196. Fixed-frequency or channel operation of a transmitter is obtained by using a ______. 19910. a. LC oscillator 19911. b. RC oscillator 19912. c. crystal oscillator 19913. d. synthesizers 19914. 19915. 197. Combining a feedback capacitor with the internal capacitance of the transistor forms a 19916. ______circuit which is used to cancel the self-oscillation. 19917. a. filter 19918. b. tank 19919. c. bridge 19920. d. feedback 19921. 19922. 198. Untuned RF transformers permit ______operation over a wide frequency range. 19923. a. narrowband 19924. b. middleband 19925. c. broadband 19926. d. any of these 19927. 19928. 19929. 19930. 19931. 19932. 19933. 19934. 19935. 19936. 19937. 19938. 19939. 19940. 19941. 19942. 19943. 19944. 19945. 19946. 19947. 19948. 19949. 19950. 19951. 19952. 19953. 19954. 19955. 19956. 19957. 19958. 19959. 19960. 19961. MULTIPLE CHOICE QUESTIONS IN 19962. WAVE PROPAGATION 19963. Electronics Systems and Technologies 19964. By 19965. Melvin C. Arceo 19966.

19967.

19968. 19969. 19970. 19971. 19972. 19973. 19974. ENCODED BY: 19975. GARCIA, Virginia Nonna H. 19976. The cumulative sum of the direct, ground-reflected, and surface waves is reflected to as ______. 19977. Space wave 19978. Ground wave 19979. Sky wave 19980. Direct waves 19981. 19982. The D layer of the ionosphere reflects ______waves. 19983. MF and HF 19984. VLF and MF 19985. MF and VHF 19986. VLF and LF 19987. 19988. A diversity scheme wherein the same radio signal is repeated or transmitted more than once. 19989. polarization diversity 19990. field component diversity 19991. time diversity 19992. frequency diversity 19993. 19994. The disadvantage of ground wave propagation is 19995. Ground waves require a relatively high transmission power 19996. Ground waves are limited to very low, low and medium frequencies requiring large antennas 19997. Ground losses very considerably with surface material 19998. Any of these 19999. 20000. A range of microwave frequencies more easily passed by the atmosphere than the others is called a 20001. window 20002. critical frequency 20003. gyro frequency range 20004. resonance in the atmosphere 20005. 20006. It is simply the orientation of the electric field vector in respect to the surface of the Earth 20007. Polarization 20008. Wavefront 20009. Rays 20010. Power density 20011. 20012. For an isotropic antenna radiating 100W of power, what is power density 1000m from the source? 20013. 1.99 uW/m^2 20014. 7.96 uW/m^2 20015. 3.22 uW/m^2 20016. 9.17 uW/m^2 20017. 20018. The ground wave eventually disappears, as moves away from the transmitter, because of 20019. interference from the sky wave 20020. loss of line-of-sight conditions 20021. maximum single hop distance limitations 20022. tilting 20023. 20024. If the electric field is propagating parallel to the surface of the Earth, the polarization is ______. 20025. Circular 20026. Vertical 20027. Horizontal 20028. Elliptical 20029. 20030. A taxi company uses a central dispatcher, with an antenna at the top of a 15m tower, to communicate with taxi cabs. The taxi antennas are on the roofs of the cars, approximately 1.5m above the ground. What is the maximum communication distance between the dispatcher and a taxi? 20031. 21 km 20032. 30 km 20033. 25 km 20034. 33 km 20035. 20036. The E layer of the ionosphere aid ______propagation and reflects ______waves 20037. MF, HF 20038. HF, MF 20039. LF, MF 20040. MF, LF 20041. 20042. When microwave signals follows the curvature of the earth, it is known as 20043. the Faraday effect 20044. ducting 20045. tropospheric scatter 20046. ionospheric scatter 20047. If the polarization vector rotates 360 degrees as the wave moves one wavelength through space and field strength is equal at all angles of polarization, the polarization is ______. 20048. Vertically polarized 20049. Horizontally polarized 20050. Circularly polarized 20051. Elliptically polarized 20052. 20053. ______travels essentially in a straight line between the transmit and the receive antennas 20054. Direct waves 20055. Sky waves 20056. Space waves 20057. Surface waves 20058. 20059. Variations brought about the revolution of the earth around the sun 20060. weather variation 20061. cyclical variation 20062. diurnal variation 20063. seasonal variation 20064. 20065. The dielectric strength of air is about 3MV/m. Arching is likely to take place at field strengths greater than that. What is the maximum power density of an electromagnetic wave in air? 20066. 40 GW/m^2 20067. 15.5 GW/m^2 20068. 23.9 GW/m^2 20069. 18.9 GW/m^2 20070. 20071. It is a single location from which rays propagate equally in all directions 20072. point source 20073. omnidirectional source 20074. ideal polarization 20075. isotropic polarized 20076. 20077. Diffraction of electromagnetic waves 20078. is caused by reflections from the ground 20079. arises only with spherical waveforms 20080. will occur when the waves pass through a large slot 20081. may occur around the edge of a sharp obstacle 20082. The critical frequency at a particular time is 11.6MHz. What is the MUF for a transmitting station if the required angle of incidence for propagation to a desired destination is 70 degrees? 20083. 34 MHz 20084. 45 MHz 20085. 40 MHz 20086. 15.5 MHz 20087. 20088. The rate at which energy passes through a given surface area in free space is called ______. 20089. capture power 20090. capture area 20091. captured power density 20092. power density 20093. 20094. A radio wave moves from air (relative permittivity is 1) to glass (relative permittivity is 7.8). Its angle of incidence is 30 degrees. What is the angle of refraction? 20095. 10.3 degrees 20096. 11.2 degrees 20097. 20.4 degrees 20098. 0.179 degrees 20099. 20100. It is the intensity of the electric and the magnetic fields of the electromagnetic wave propagating in free space 20101. field intensity 20102. field density 20103. power intensity 20104. power intensity 20105. 20106. Radio propagation was predicted mathematically by 20107. Heinrich R. Hertz 20108. Guglielmo Marconi 20109. James Clerk Maxwell 20110. Alexander Graham Bell 20111. 20112. Tropospheric scatter is used with frequencies in the following range 20113. HF 20114. VHF 20115. UHF 20116. VLF 20117. A point source that radiates power at a constant rate uniformly in all directions. 20118. isotropic source 20119. isotropic radiator 20120. point source 20121. any of these 20122. 20123. The transmitting distance with direct waves is limited to short distances and strictly a function of the ______of the transmitting and receiving antenna. 20124. frequency 20125. phase 20126. power 20127. height 20128. 20129. One nautical mile is equal to ______statute miles. 20130. 2.12 20131. 1.15 20132. 2.54 20133. 1.90 20134. 20135. It is the deflection or bending of electromagnetic waves such as radio waves, light or even sound when the waves cross the boundary line between two mediums with different characteristics. 20136. reflection 20137. diffraction 20138. refraction 20139. dispersion 20140. 20141. The reduction of power density with distance is equivalent to a power loss. 20142. absorption 20143. attenuation 20144. distance loss 20145. power dissipation 20146. 20147. The signal refracted back from the ionosphere strikes the earth and is reflected back up to the ionosphere again to be bent and sent back to earth. 20148. skip transmission 20149. multi-hop transmission 20150. multi transmission 20151. hop transmission 20152. 20153. Electromagnetic waves are refracted when they 20154. pass into a medium of different dielectric constant 20155. are polarized at right angles to the direction of propagation 20156. encounter a perfectly conducting surface 20157. pass through a small slot in a conducting plane 20158. 20159. The reduction in power density due to nonfree-space propagation 20160. absorption 20161. attenuation 20162. power dissipation 20163. distance loss 20164. 20165. ______is the signal that is radiated by the antenna into the atmosphere where it is bent or reflected back to earth. 20166. ground wave signal 20167. sky wave signal 20168. space wave signal 20169. direct waves signal 20170. 20171. It is a type of fading having different effect different frequencies 20172. Selective fading 20173. Polarization fading 20174. Interference fading 20175. Absorption fading 20176. 20177. It is defined as the modulation or redistribution of energy within a wave front as it passes near the edge of an opaque object. 20178. a. refraction 20179. b. scattering 20180. c. reflection 20181. d. diffraction 20182. 20183. What type of modulation is primarily used in ground wave propagation? 20184. Frequency modulation 20185. Amplitude modulation 20186. Phase modulation 20187. Pulse modulation 20188. 20189. It states that every point on a given spherical wavefront can be considered as a secondary point source of electromagnetic waves from which other secondary waves or wavelets are radiated outward. 20190. Hertzian principle 20191. Maxwell’s principle 20192. Huygen’s principle 20193. Marconi’s principle 20194. 20195. Calculate the electric field intensity, in volts per meter, 20 km from a 1-kW source. 20196. 3.44 mW/m 20197. 7.65 mW/m 20198. 8.66 mW/m 20199. 1.45 mW/m 20200. 20201. The absorption of radio waves by the atmosphere depends on 20202. their frequency 20203. their distance from the transmitter 20204. the polarization of waves 20205. is always vertical in an isotropic medium 20206. 20207. Calculate the radio horizon for a 500-ft transmitting antenna and receiving antenna of 20 ft. 20208. 23.1 mi 20209. 31.2 mi 20210. 14.8 mi 20211. 37.9 mi 20212. 20213. Calculate the power received from a 20-W transmitter, 22,000 miles from earth, if the receiving antenna has an effective area of 1600m^2 20214. 4.06 x 10^-12 W 20215. 2.03 x 10^-12 W 20216. 1.02 x 10^-12 W 20217. 0.91 x 10^-12 W 20218. 20219. As electromagnetic waves travel in free space, only one of the following can happen to them 20220. absorption 20221. attenuation 20222. refraction 20223. reflection 20224. Electromagnetic waves travelling within Earth’s atmosphere is called 20225. Space wave 20226. Surface wave 20227. Terrestrial wave 20228. Sky-wave 20229. 20230. Calculate the power density in watts per square meter (on earth) from a 10-W satellite source that is 22,000 miles from earth. 20231. 3.17 x 10^ -16 W/m^2 20232. 6.35 x 10^ -16 W/m^2 20233. 2.31 x 10^ -16 W/m^2 20234. 1.21 x 10^ -16 W/m^2 20235. 20236. It is termed used to describe variations in signal strength that occur at the receiver during this time a signal is being received. 20237. skipping 20238. attenuation 20239. absorption 20240. fading 20241. 20242. The constant temperature stratosphere is called ______. 20243. E-layer 20244. S-layer 20245. isothermal region 20246. ionosthermal region 20247. 20248. It is the tendency of the sun to have grayish-black blemishes, seemingly at random times and at random place, on its fiery surface. 20249. solar intensity 20250. sunspot 20251. solar flare 20252. solar flux 20253. 20254. In electromagnetic waves, polarization 20255. is caused by reflection 20256. is due to the transverse nature of the waves 20257. results from the longitudinal nature of waves 20258. is always vertical in an isotropic medium 20259. 20260. It is an earth-guided electromagnetic wave that travels over the surface of the Earth 20261. Surface waves 20262. Sky waves 20263. Direct waves 20264. Space waves 20265. 20266. Frequencies in the UHF range normally propagate by means of 20267. Ground waves 20268. Sky waves 20269. Surface waves 20270. Space waves 20271. 20272. The curvature of the Earth presents a horizon to space wave propagation commonly called ______. 20273. Optical horizon 20274. Radio horizon 20275. Horizontal horizon 20276. Vertical horizon 20277. 20278. Electromagnetic waves that are directed above the horizon level is called ______. 20279. direct waves 20280. sky waves 20281. space waves 20282. surface waves 20283. 20284. The refracting and reflecting action of the ionosphere and the ground is called 20285. sliding 20286. skipping 20287. hopping 20288. boosting 20289. 20290. An electrical energy that is escaped in free space 20291. Electrical signal 20292. Electromagnetic waves 20293. Magnetic waves 20294. Electromagnetism 20295. 20296. The layer of the ionosphere which farthest from the sun 20297. D layer 20298. E layer 20299. F1 layer 20300. F2 layer 20301. 20302. A condition which manifest itself in the form of double-image distortion 20303. running 20304. fading 20305. ghosting 20306. snowing 20307. 20308. The D layer of the ionosphere absorbs ______waves. 20309. LF and MF 20310. MF and HF 20311. HF and VHF 20312. VHF and UHF 20313. 20314. The E layer of the ionosphere is sometimes called ______20315. Kennely-Heavisides 20316. Sporadic-E layer 20317. E-densed layer 20318. Kennely layer 20319. 20320. It is defined as the higher frequency that can be propagated directly upward and still be returned to earth by the ionosphere 20321. critical angle 20322. maximum usable frequency 20323. critical frequency 20324. virtual height 20325. 20326. The maximum vertical angle at which electromagnetic waves can be propagated and still be reflected back by the ionosphere 20327. numerical aperture 20328. incident angle 20329. critical angle 20330. refracted angle 20331. 20332. It is defined as the plane joining all points of equal phase 20333. rays 20334. electromagnetic wave 20335. wavefront 20336. isotropic source 20337. 20338. It is the height above Earth’s surface from which a reflected wave appears to have been reflected. 20339. virtual height 20340. maximum height 20341. vertical height 20342. horizontal height 20343. 20344. It is the highest frequency that can be used for sky wave propagation between two specific points on Earth’s surface 20345. optimum working frequency 20346. maximum usable frequency 20347. critical frequency 20348. maximum frequency 20349. 20350. The polarization of electromagnetic waves can be determined by the direction of the 20351. E field 20352. H field 20353. propagation 20354. both E and H field 20355. 20356. 85 percent of the maximum usable frequency (MUF) is called ______. 20357. maximum usable frequency 20358. optimum working frequency 20359. critical frequency 20360. maximum frequency 20361. 20362. It is defined as the minimum distance from the transmit antenna that a sky wave at a given frequency will be returned to earth. 20363. skip distance 20364. skip zone 20365. skip frequency distance 20366. skip zone frequency 20367. 20368. At distance greater than the skip distance, two rays can take different paths and still be returned to the same point on Earth. The two rays are called lower rays and ______. 20369. Pedersen ray 20370. Light ray 20371. Huygen’s ray 20372. Miller’s ray 20373. 20374. Undesired radiated energy from a radio transmitter or in another source. 20375. ESD 20376. EMI 20377. RFI 20378. ESI 20379. 20380. The area between where the surface waves are completely dissipated and the point where the first sky wave returns to earth is called ______. 20381. skip distance 20382. skip distance zone 20383. optical horizon 20384. quiet zone 20385. 20386. The undesired radiated energy that may cause interference with other electronic equipment in the vicinity. 20387. ESD 20388. EMI 20389. RFI 20390. ESI 20391. 20392. It is defined as the loss incurred by an electromagnetic wave as it propagates in a straight line through a vacuum with no absorption or reflection of energy from nearby objects. 20393. free-space path loss 20394. free space loss 20395. path loss 20396. any of these 20397. 20398. To increase the transmission distance of a UHF signal, which of the following should be done? 20399. increase the antenna gain 20400. increase antenna height 20401. increase transmitter power 20402. increase receiver sensitivity 20403. 20404. For a carrier frequency of 6 GHz and a distance of 50 km, determine the free- space path loss 20405. 132 dB 20406. 123 dB 20407. 142 dB 20408. 152 dB 20409. A microwave-transmitting antenna is 550 ft high. The receiving antenna is 200 ft high. The maximum transmission distance is 20410. 20 mi 20411. 33.2 mi 20412. 38.7 mi 20413. 53.2 mi 20414. 20415. Indicate which one of the following term applies to troposcatter propagation 20416. SIDs 20417. Fading 20418. Atmospheric storms 20419. Faraday’s rotation 20420. 20421. Line-of-sight communications is not a factor in which frequency range? 20422. VHF 20423. UHF 20424. HF 20425. Microwave 20426. 20427. VLF waves are used for some types of services because 20428. of the low powers required 20429. the transmitting antenna are of convenient size 20430. they are very reliable 20431. affected by the solar cycle 20432. 20433. Microwave signals propagate by way of the 20434. direct wave 20435. sky wave 20436. surface wave 20437. standing wave 20438. 20439. Indicate which of the following frequencies cannot be used for reliable beyond- the-horizon terrestrial communications without repeaters: 20440. 20 kHz 20441. 15 MHz 20442. 900 MHz 20443. 12 GHz 20444. 20445. The type of radio wave responsible for long-distance communications by multiple skips is the 20446. ground wave 20447. direct wave 20448. surface waves 20449. sky wave 20450. 20451. High-frequency waves are 20452. absorbed by the F2 layer 20453. reflected by the D layer 20454. capable of use for long-distance communications on the moon 20455. affected by the solar cycle 20456. 20457. The ionosphere has its greatest effect on signals in what frequency range? 20458. 300 kHz to 3 MHz 20459. 3 to 30 MHz 20460. 30 to 300 MHz 20461. above 300 MHz 20462. 20463. Distances near the skip distance should be used for sky-wave propagation 20464. to avoid tilting 20465. to prevent sky-wave and upper ray interference 20466. to avoid Faraday effect 20467. so as not to exceed the critical frequency 20468. 20469. Ground-wave communications is most effective in what frequency range? 20470. 300 kHz to 3 MHz 20471. 3 to 30 MHz 20472. 30 to 300 MHz 20473. above 300 MHz 20474. 20475. The ionosphere causes radio signals to be 20476. diffused 20477. absorbed 20478. refracted 20479. reflected 20480. 20481. Helical antenna are often used for satellite tracking at VHF because of 20482. troposcatter 20483. superrefraction 20484. ionospheric refraction 20485. the Faraday effect 20486. A ship-to-ship communication system is plagued by fading. The best solution seem to use of 20487. a more directional antenna 20488. a broadband antenna 20489. frequency diversity 20490. space diversity 20491. 20492. It is defined as the ratio of the electric field intensity of the reflected wave to that of the incident wave 20493. refractive index 20494. numerical aperture 20495. reflection coefficient 20496. absorption coefficient 20497. 20498. It is the measure of energy received per unit time, per unit area, per unit frequency interval. 20499. solar intensity 20500. sunspot 20501. solar flare 20502. solar flux 20503. 20504. A long period with lack of any solar activity 20505. El Niño 20506. La Niña 20507. Maunder period 20508. Sunspots 20509. 20510. As a ground-wave signal moves away from the transmitter, the ground wave eventually disappears due to the 20511. absorption 20512. tilting 20513. refraction 20514. diffraction 20515. 20516. It is the lowest layer of the atmosphere where all weather disturbances takes place 20517. D layer 20518. Stratosphere 20519. Ionosphere 20520. Troposphere 20521. 20522. It is the lower limit of the range of frequencies that provide useful communication between two given points by the way of the ionosphere. 20523. MUF 20524. LUF 20525. OWF 20526. MMF 20527. 20528. It is the area that lies between the outer limit of the ground-wave range and the inner edge of energy return from the ionosphere 20529. skip distance 20530. skip zone 20531. virtual height 20532. optical horizon 20533. 20534. Variations brought about by the rotation of the earth around its axis. 20535. cyclical rotation 20536. seasonal variation 20537. diurnal variation 20538. weather variation 20539. 20540. Ionospheric irregularity caused by solar flares, which are gigantic emissions of hydrogen from the sun. 20541. Sudden ionospheric disturbances 20542. Dillenger fadeouts 20543. Mogul-Delliger fadeouts 20544. Any of these 20545. 20546. It is a type of fading caused by so-called Faraday effect or Faraday rotation 20547. interference fading 20548. absorption fading 20549. selective fading 20550. polarization fading 20551. 20552. Radio horizon is ______greater than the optical horizon. 20553. one-third 20554. four-third 20555. two-third 20556. twice 20557. 20558. An increase in temperature with height which gives rise to superrefraction or ducting is known as ______. 20559. height inversion 20560. depth inversion 20561. temperature inversion 20562. ionospheric inversion 20563. 20564. A region in which superrefraction occurs which is formed in the troposphere when the 20565. layer of cool air becomes trapped underneath a layer of warmer air. 20566. a. duct 20567. b. dielectric area 20568. c. gateway 20569. d. window 20570. 101. A range of frequency little attenuated by the atmosphere is called 20571. a. slide 20572. b. door 20573. c. window 20574. d. frame 20575. 20576. 102. It is defined as either of two acute angles formed by the intersection of the two portions of the tropospheric scatter beam tangent to the earth’s surface. 20577. a. critical angle 20578. b. scatter angle 20579. c. backscatter angle 20580. d. sidescatter angle 20581. 20582. 103. It is a device that permits two different transmitters to operate with a single antenna 20583. a. duplexer 20584. b. diplexer 20585. c. isolator 20586. d. circulator 20587. 20588. 104. It is a gradual shift in polarization of the signal in the medium. 20589. a. fading 20590. b. faraday effect 20591. c. ghosting 20592. d. multipath fading 20593. 20594. 105. A diversity scheme wherein the receiver receives two fading signals from two different 20595. directions 20596. frequency diversity 20597. time diversity 20598. angle diversity 20599. space diversity 20600. 106. The radio wavelength known as ______falls within the medium frequency range 20601. a. centimetric wave 20602. b. decametric wave 20603. c. hectometric wave 20604. d. myriametric wave 20605. 20606. 107. The most dense of all ionized layer of the ionosphere 20607. a. E 20608. b. F1 20609. c. F2 20610. d. D 20611. 20612. 108. The frequency band used as sub-carriers, or signals which carry the baseband modulating information but in turn modulate another higher-frequency carrier is ______. 20613. a. LF 20614. b. MF 20615. c. VLF 20616. d. VH 20617. 20618. 109. The range of frequency band termed as super high frequency (SHF) is within ______. 20619. a. 30-300 GHz 20620. b. 30-300 MHz 20621. c. 3-30 GHz 20622. d. 300-3000 MHz 20623. 20624. 110. Electric field that lies in a plane perpendicular to the earth’s surface. 20625. a. circular polarization 20626. b. vertical polarization 20627. c. horizontal polarization 20628. d. elliptical polarization 20629. 20630. 111. The magnetic field of an antenna is perpendicular to the earth. The antenna’s polarization 20631. a. is vertical 20632. b. is horizontal 20633. c. is circular 20634. d. cannot be determined from the information given 20635. 20636. 112. The surface wave is effective only at frequencies below about ______MHz. 20637. a. 30 20638. b. 3 20639. c. 300 20640. d. 0.3 20641. 20642. 113. What wave propagation are attenuated within a few miles? 20643. a. space 20644. b. sky 20645. c. ground 20646. d. direct 20647. 20648. 114. What happens to wave velocity as it passes from air to ionosphere? 20649. a. increases 20650. b. decreases 20651. c. remain the same 20652. d. not a factor 20653. 20654. 115. What wavelength radiations tend to be transmitted entirely between ionosphere and earth? 20655. a. long 20656. b. short 20657. c. medium 20658. d. millimeter 20659. 20660. 116. What effect do sunspots have on the ionosphere? 20661. a. makes more rare and regular 20662. b. makes more dense and irregular 20663. c. makes less dense and regular 20664. d. makes less dense and irregular 20665. 20666. 117. What is a double-hop signal? 20667. a. ground, ionosphere, ground and back to ionosphere 20668. b. ground, ground, ionosphere, and ionosphere 20669. c. ionosphere, ionosphere, ground and ground 20670. d. ionosphere, ground, ionosphere and back to ground 20671. 20672. 118. What is the major cause of fading? 20673. a. phase difference 20674. b. topographic variation 20675. c. climate 20676. d. ionosphere variation 20677. 20678. 119. Where is the skip zone? 20679. a. between the sky and the first reflected wave 20680. b. between end of ground and first reflected wave 20681. c. between end of ground and farthest reflected wave 20682. d. between the end of sky to the farthest reflected wave 20683. 20684. 120. What wave is the same day or night? 20685. a. sky 20686. b. space 20687. c. direct 20688. d. ground 20689. 20690. 121. Why do HF communications system shift frequencies at different times of day? 20691. a. to take advantage of best reflected signals 20692. b. to conserve the energy used 20693. c. to create diversity 20694. d. to improve noise performance 20695. 20696. 122. Scatter transmission is used at what frequencies? 20697. a. EHF and VLF 20698. b. HF and VHF 20699. c. VHF and UHF 20700. d. ELF and VLF 20701. 20702. 123. Over what areas ducts often form? 20703. a. desert 20704. b. water 20705. c. forest 20706. d. mountain 20707. 20708. 124. Polarization named for ______component of the wave? 20709. a. static 20710. b. magnetic 20711. c. direction 20712. d. propagation 20713. 20714. 125. What polarization is employed in an AM broadcasting? 20715. a. horizontal 20716. b. parallel 20717. c. transverse 20718. d. vertical 20719. 20720. 20721. 20722. 20723. 20724. 20725. 20726. 20727. 20728. 20729. 20730. 20731. 20732. MULTIPLE CHOICE QUESTIONS IN 20733. DIGITAL AND DATA COMMUNICATIONS 20734. Electronics Systems and Technologies 20735. By 20736. Melvin C. Arceo 20737. 20738. 20739. 20740. 20741. 20742. 20743. 20744. ENCODED BY: 20745. GIRAO, Edward Joseph D. 20746. 1. It is defined as knowledge or intelligence that is communicated between two or more points. 20747. A. Carrier 20748. B. Sideband 20749. C. Information 20750. D. Broadband 20751. 2. What is the category of data transmission if the binary pulse is maintained for the entire bit time? 20752. A. Return to zero 20753. B. Bipolar 20754. C. Unipolar 20755. D. Non return to zero 20756. 3. Which medium is most widely used in LANs? 20757. A. Twin lead 20758. B. Fiber-optic cable 20759. C. Twisted pair 20760. D. Coax 20761. 4. These are used for transmission of PCM encoded time-division multiplexed digital signal 20762. A. I carriers 20763. B. E carriers 20764. C. A carriers 20765. D. T carriers 20766. 5. Which of the following is not a typical FDM application? 20767. A. telemetry 20768. B. stereo broadcasting 20769. C. telephone 20770. D. secure communications 20771. 6. A LAN device that use to interconnect two networks that use different protocols and formats 20772. A. Gateways 20773. B. Routers 20774. C. Bridges 20775. D. Hubs 20776. 7. A pulse modulation technique as the width of a constant amplitude pulse is varied proportional to the amplitude of the analog signal at the time the signal is sampled. 20777. A. Pulse Width Modulation 20778. B. Pulse Length Modulation 20779. C. Pulse Duration Modulation 20780. D. All of these 20781. 8. The FDM telephone systems accommodate many channels by 20782. A. Increasing the multiplexer size 20783. B. Using many final carriers 20784. C. Narrowing the bandwidth of each 20785. D. Using multiple levels of multiplexing 20786. 9. It is the transmittal of digitally modulated analog signals (carrier) between two or more points in a communications system. 20787. A. Digital Modulation 20788. B. Digital Transmission 20789. C. Digital Communications 20790. D. Pulse Modulation 20791. 10. Indicate which of the following systems is digital 20792. A. Pulse-position modulation 20793. B. Pulse-code modulation 20794. C. Pulse-width modulation 20795. D. Pulse-frequency modulation 20796. 11. Classification of protocol that interprets a frame of data as a group of successive bit combined into predetermined pattern of fixed length, usually 8 bits each. 20797. A. Character-oriented protocols 20798. B. Byte-oriented protocols 20799. C. Bit-oriented protocol 20800. D. Character and Byte-oriented protocols 20801. 12. Dividing the data block by a constant produces a remainder that is used for error detection. It is called the 20802. A. Vertical redundancy checking 20803. B. Horizontal redundancy checking 20804. C. Block check character 20805. D. Cyclic redundancy check 20806. 13. Which of the following is not a benefit of spread spectrum? 20807. A. Jam-proof 20808. B. Security 20809. C. Immunity to fading 20810. D. Noise proof 20811. 14. Converting analog signals to digital is done by sampling and ______. 20812. A. quantizing 20813. B. companding 20814. C. pre-emphasis 20815. D. mixing 20816. 15. It is a process of converting an infinite number of possibilities to a finite number of conditions 20817. A. Sampling 20818. B. Coding 20819. C. Quantization 20820. D. Aliasing 20821. 16. In T1, it is equal to the reciprocal of the sample rate 20822. A. Slot time 20823. B. Transmission time 20824. C. Frame time 20825. D. Bit rate 20826. 17. What is the final output of a multiplexer? 20827. A. Baseband 20828. B. Composite baseband 20829. C. Information 20830. D. Composite carrier 20831. 18. The baud rate 20832. A. is always equal to the bit transfer rate 20833. B. is equal to the twice the bandwidth of an ideal channel 20834. C. is not equal to the signaling rate 20835. D. is equal to one-half the bandwidth of an ideal channel 20836. 19. Bit errors in data transmission are usually caused by 20837. A. equipment failures 20838. B. typing mistakes 20839. C. noise 20840. D. Poor S/N ratio at receiver 20841. 20. A digital modulation technique which is a form of constant-amplitude angle modulation similar to standard frequency modulation except the modulating signal is binary signal that varies between two discreet voltage levels. 20842. A. QAM 20843. B. ASK 20844. C. PSK 20845. D. FSK 20846. 21. Start and stop bits, respectively, are 20847. A. Mark, space 20848. B. Space, mark 20849. C. Space, space 20850. D. Mark, mark 20851. 22. It is the processing of analog signals using digital methods and includes bandlimiting and signals with filters, amplitude equalization, and phase shifting 20852. A. Digital communications 20853. B. Digital signal processing 20854. C. Data communications 20855. D. Carrier recovery method 20856. 23. It is a network access method used primarily with LANs configured in a ring topology using either baseband or broadband transmission formats. 20857. A. Ethernet 20858. B. Token passing 20859. C. Token ring 20860. D. Token bus 20861. 24. A small telephone switching system that can be used as a LAN is called 20862. A. Ring 20863. B. WAN 20864. C. UART 20865. D. PBX 20866. 25. The most common method used for sampling voice signals in PCM systems. 20867. A. unnatural sampling 20868. B. flat top smpling 20869. C. natural sampling 20870. D. free sampling 20871. 26. In PCM, it converts the PAM samples to parallel PCM codes 20872. A. Analog-to-digital Converter 20873. B. Digital-to-analog Converter 20874. C. Pre-emphasis circuit 20875. D. Compander 20876. 27. The OSI layer that provides the control functions necessary to establish manage, and terminate the connections as required to satisfy the user request. 20877. A. Application layer 20878. B. Network layer 20879. C. Session layer 20880. D. Physical layer 20881. 28. In PAM demultiplexing, the receiver clock is derived from 20882. A. standard radio station WWW 20883. B. a highly accurate internal oscillator 20884. C. the PAM signal itself 20885. D. the 60-Hz power line 20886. 29. It is also known as digital modulation 20887. A. digital transmission 20888. B. digital sampling 20889. C. digital radio 20890. D. data transmission 20891. 30. Time-division multiplex 20892. A. can be used with PCM only 20893. B. combines five groups into a supergroup 20894. C. stacks 24 channels in adjacent frequency slots 20895. D. interleaves pulses belonging to different transmissions 20896. 31. It is a numerical indication of how efficiently a PCM code is utilized 20897. A. Coding efficiency 20898. B. Companding 20899. C. Pre-emphasis 20900. D. Dynamic Range 20901. 32. Type of PCM which is designed to take advantage of the sample-to sample redundancies in the typical speech waveform 20902. A. Single-bit PCM code 20903. B. Pulse code modulation 20904. C. Differential PCM 20905. D. Data modulation 20906. 33. The Basic Rate Interference (BRI) of ISDN has a total bit rate of ______20907. A. 192 kbps 20908. B. 148 kbps 20909. C. 64 kbps 20910. D. 1.544 Mbps 20911. 34. A form of angle-modulated, constant amplitude digital modulation similar to conventional phase modulation except its input is binary digital signal and there are limited number of output phase possible 20912. A. ASK 20913. B. PSK 20914. C. FSK 20915. D. QAM 20916. 35. The main circuit in a PSN generator is 20917. A. XOR 20918. B. Multiplexer 20919. C. Shift register 20920. D. Mixer 20921. 36. The circuit that performs demultiplexing in an FDM is _____ 20922. A. Op-amp 20923. B. Bandpass filter 20924. C. Discriminator 20925. D. Subcarrier oscillator 20926. 37. _____ defines how a user gets control of the channel so as to allow transmission. 20927. A. channel access 20928. B. collision detection 20929. C. collision avoidance 20930. D. carrier sense 20931. 38. The fastest LAN topology is 20932. A. ring 20933. B. bus 20934. C. star 20935. D. square 20936. 39. It is a theoretical expectation of the bit error rate in the system 20937. A. probability of errors 20938. B. error detection 20939. C. error control 20940. D. bit error rate 20941. 40. It is simply the data rate at which serial PCM bits are clocked out of the PCM encoder onto the transmission line. 20942. A. line speed 20943. B. baud rate 20944. C. output rate 20945. D. bit rate 20946. 41. A quantizing is _____ 20947. A. Multiplexer 20948. B. Demultiplexer 20949. C. A/D converter 20950. D. D/A converter 20951. 42. Refers to the rate of change of a signal on a transmission medium after encoding and modulation have occurred 20952. A. baud rate 20953. B. phase shift 20954. C. bit rate 20955. D. frequency deviation 20956. 43. The magnitude difference between adjacent steps in quantization is called _____ 20957. A. Quantum 20958. B. Step size 20959. C. Resolution 20960. D. Any of these 20961. 44. It is a set of rules implementing and governing an orderly exchange of data between layers of two devices, such as line control units and front-end processors. 20962. A. Data Link Protocol 20963. B. Network Protocol 20964. C. Pont to Point Protocol 20965. D. File Transfer Protocol 20966. 45. A signaling system in which each letter of the alphabet is represented by a different symbol is not used because 20967. A. it would be too difficult for an operator to memorize 20968. B. it is redundant 20969. C. noise would introduce too many errors 20970. D. too many pulses per letter are required 20971. 46. A modulation process that involves conversion of a waveform from analog to digital form by means of coding 20972. A. PDM 20973. B. PCM 20974. C. PLM 20975. D. PAM 20976. 47. What is the bandwidth required to transmit at a rate of 10 Mbps in the presence of a 28-Db S/N ratio? 20977. A. 1.075 MHz 20978. B. 10 MHz 20979. C. 5 MHz 20980. D. 10.75 MHz 20981. 48. The slope of the analog signal is greater than the delta modulator can maintain 20982. A. overload distortion 20983. B. granular noise 20984. C. slope overload 20985. D. peak limiting 20986. 49. A scheme in which several channels are interleaved and then transmitted together is known as 20987. A. frequency division multiplex 20988. B. time-division multiplex 20989. C. a group 20990. D. a supergroup 20991. 50. The best frequency demodulator is 20992. A. PLL discriminator 20993. B. Pulse-averaging discriminator 20994. C. Foster-Seeley discriminator 20995. D. Ratio detector 20996. 51. What property distinguishes digital radio systems from conventional analog communications system? 20997. A. the type of carrier used in transmission of data 20998. B. the nature of the modulating signal 20999. C. the type of modulation of data to be used 21000. D. the nature of the transmitter and receiver to be used 21001. 52. The circuit switch is a _____ switch. 21002. A. See-through 21003. B. Transparent 21004. C. Vague 21005. D. Opaque 21006. 53. A carrier recovery circuit is not needed with 21007. A. FSK 21008. B. BPSK 21009. C. DPSK 21010. D. QAM 21011. 54. The Hartley-Shannon theorem sets a limit on the 21012. A. the highest frequency that may be sent over a given channel 21013. B. maximum capacity of a channel with a given noise level 21014. C. maximum number of coding levels in a channel with a given noise level 21015. D. maximum number of quantizing levels in a channel of a given bandwidth 21016. 55. The phase relationship between signaling elements for BPSK is the optimum signaling format and occurs only when two binary signal levels are allowed and when one signal is the exact negative of the other 21017. A. Antipodal signaling 21018. B. Carrier recovery 21019. C. Squaring loop 21020. D. Phase referencing 21021. 56. Pulse-amplitude modulation signals are multiplexed by using 21022. A. Subcarrier 21023. B. Bandpass filters 21024. C. A/D Converters 21025. D. FET switches 21026. 57. It is the ratio of the transmission bit rate to the minimum bandwidth required for a particular modulation scheme. 21027. A. Bandwidth efficiency 21028. B. All of these 21029. C. Information density 21030. D. Spectral efficiency 21031. 58. Ethernet is a baseband transmission system designed by _____ 21032. A. Thomas Murray and Robert Metcalfe 21033. B. David Boggs and Thomas Murray 21034. C. Thomas Murray and Emile Baudot 21035. D. Robert Metcalfe and David Boggs 21036. 59. It is a system where the digital signals are placed directly on the coaxial cable. 21037. A. Broadband 21038. B. Baseband 21039. C. CSMA/CD 21040. D. Token ring 21041. 60. A basic group B 21042. A. occupies the frequency range from 60 to 108 kHz 21043. B. consists of erect channels only 21044. C. is formed at the group translating equipment 21045. D. consists of five supergroups 21046. 61. Which of the following is not primarily a type of data communications? 21047. A. telephone 21048. B. teletype 21049. C. telegraph 21050. D. CW 21051. 62. Packets which is self-contained and travels through the network independent of other packets of the same message by whatever means available. 21052. A. Packet 21053. B. Frame 21054. C. Datagram 21055. D. Data 21056. 63. Transmitting the data signal directly over the medium is referred to as 21057. A. baseband 21058. B. broadband 21059. C. ring 21060. D. bus 21061. 64. The main reason that serial transmission is preferred to parallel transmission is that? 21062. A. serial is faster 21063. B. serial requires only a single channel 21064. C. serial requires multiple channels 21065. D. parallel is too expensive 21066. 65. Which of the following is not a LAN? 21067. A. PBX system 21068. B. Hospital system 21069. C. Office building system 21070. D. Cable TV system 21071. 66. A modulation technique where data rates in excess of 56 kbps can be achieved over telephone circuits 21072. A. ASK 21073. B. Trellis code modulation 21074. C. GSK 21075. D. any of these 21076. 67. It is how the primary designates the secondary as a designation or recipient of data. 21077. A. Line turnaround 21078. B. Selection 21079. C. Line control 21080. D. Control protocol 21081. 68. It is the process of compressing and expanding and is a means of improving the dynamic range of a communications system. 21082. A. Pre-emphasis 21083. B. Filtering 21084. C. De-emphasis 21085. D. Companding 21086. 69. The supergroup pilot is 21087. A. applied at each multiplexing bay 21088. B. used to regulate the gain of individual repeaters 21089. C. applied at each adjustable equalizer 21090. D. fed in at a GTE 21091. 70. The time it takes to transmit one TDM frame is called _____ 21092. A. Slot time 21093. B. Frame time 21094. C. Transmission time 21095. D. any of these 21096. 71. It is the thermal noise power normalized to 1-Hz bandwidth 21097. A. power density ratio 21098. B. thermal noise 21099. C. noise power density 21100. D. ambient temperature noise 21101. 72. It is the procedure used to decide which device has the permission to transmit at any given time. 21102. A. Flow control 21103. B. Sequence control 21104. C. Line control 21105. D. Frame 21106. 73. Any rounded-off errors in the transmitted signal are reproduced when the code is converted back to analog in the receiver 21107. A. Aperture error 21108. B. Quantization error 21109. C. Aperture distortion 21110. D. Slope overload 21111. 74. The biggest disadvantage of PCM is 21112. A. its inability to handle analog signals 21113. B. the high error rate which is quantizing noise introduces 21114. C. its incompatibility with TDM 21115. D. the large bandwidths that are required for it 21116. 75. T1 stands for 21117. A. Transmission one 21118. B. Telecommunication one 21119. C. Telex one 21120. D. Transmission line one 21121. 76. Involves compression in the transmitter after the input pulse has been converted to a linear PCM code and then expansion in the receiver prior to PCM coding 21122. A. analog companding 21123. B. A-law companding 21124. C. digital companding 21125. D. u-law companding 21126. 77. Mark and space refer respectively to 21127. A. dot and dash 21128. B. message and interval 21129. C. binary 1 and binary 0 21130. D. on and off 21131. 78. Variation of biphase that is used for encoding SMPTE (Society of Motion Picture and Television Engineers) time code data and for recording on video tapes 21132. A. Biphase-M 21133. B. B8Z 21134. C. Manchester 21135. D. UPNRZ 21136. 79. Pulse-width modulation may be generated 21137. A. by differentiating pulse-position modulation 21138. B. with a monostable multivibrator 21139. C. by integrating the signal 21140. D. with a free-running multivibrator 21141. 80. The ISDN channel D designates _____ which contains control information. 21142. A. Data 21143. B. Flow 21144. C. Control 21145. D. Bearer 21146. 81. A transmission of binary data which involves the transmission of two non-zero voltage level 21147. A. Unipolar 21148. B. Polar 21149. C. Bipolar 21150. D. Nonreturn to Zero 21151. 82. Switching systems 21152. A. improve the efficiency of data transfer 21153. B. are not used in data systems 21154. C. require additional lines 21155. D. are limited to small data networks 21156. 83. It involves converting standard logic levels to a form more suitable to telephone transmission lines 21157. A. Transmission line encoding 21158. B. Physical line encoding 21159. C. Digital line encoding 21160. D. Multiplexing 21161. 84. The primary advantage of digital transmission 21162. A. economical 21163. B. reliability 21164. C. noise immunity 21165. D. efficiency 21166. 85. Part of the PCM system that prevents aliasing or foldover distortion 21167. A. Bandpass filter 21168. B. Anti-foldover distortion 21169. C. Anti-aliasing 21170. D. Any of these 21171. 86. It is defined as the process of transforming messages or signals in accordance with a definite set of rules. 21172. A. Quantizing 21173. B. Sampling 21174. C. Coding 21175. D. Decoding 21176. 87. The PCM code for each channel occupies a fixed time slot called 21177. A. Frame time 21178. B. Baud 21179. C. Transmission line 21180. D. Epoch 21181. 88. The building block of a parity or BCC generator is _____. 21182. A. Shift register 21183. B. XOR 21184. C. 2-to-4 level converter 21185. D. UART 21186. 89. An IC that contains A/D and D/A converters, companders, and parallel-to- serial converters is called a 21187. A. Codec 21188. B. Data converter 21189. C. Multiplexer 21190. D. Modem 21191. 90. Data Communications refers to the transmission of 21192. A. voice 21193. B. video 21194. C. computer data 21195. D. all of above 21196. 91. The number of amplitude, frequency, or phase changes that take place per second is known as the 21197. A. data rate in bits per second 21198. B. frequency of operation 21199. C. speed limit 21200. D. baud rate 21201. 92. The basic modulator and demodulator circuits in PSK are 21202. A. PLLs 21203. B. Balanced modulators 21204. C. Shift registers 21205. D. Linear summers 21206. 93. What is the result if the input of ADC is changing while performing vonersion? 21207. A. Aperture error 21208. B. Overload distortion 21209. C. Aliasing 21210. D. Aperture distortion 21211. 94. Information capacity is convenient to express as 21212. A. baud 21213. B. bits 21214. C. dot length 21215. D. bits per second or bps 21216. 95. Which medium is the least susceptible to noise? 21217. A. twin lead 21218. B. fiber-optic cable 21219. C. twisted pair 21220. D. coax 21221. 96. The RS-232 interface 21222. A. interconnects data sets and transmission circuits 21223. B. uses several different connectors 21224. C. permits custom wiring of signal lines to the connector pins as desired 21225. D. all of the above 21226. 97. The ISDN channel B designates _____ 21227. A. Bearer 21228. B. Data 21229. C. Control 21230. D. Flow 21231. 98. Data transmission of the character at a time with start and stop bits is known as what type of transmission? 21232. A. asynchronous 21233. B. serial 21234. C. synchronous 21235. D. parallel 21236. 99. Sampling technique that when the tops of the sample pulses retain their natural shape during the sample interval 21237. A. unnatural sampling 21238. B. flat top sampling 21239. C. natural sampling 21240. D. free sampling 21241. 100. A modem converts 21242. A. Analog signals to digital 21243. B. Digital signals to analog 21244. C. Digital signals to analog and vice-versa 21245. D. none of these 21246. 101. It is a large scale integration chip designed for use in telecommunication industry for private branch exchanges, central office switches, digital handsets and digital echo suppressors. 21247. A. Vocoder 21248. B. Modem 21249. C. Codec 21250. D. Muldem 21251. 102. What is the type of mastergroup used for low-capacity microwave systems? 21252. A. A600 21253. B. U600 21254. C. L600 21255. D. L400 21256. 103. An FDM hierarchy which is formed by frequency-division multiplexing five groups containing 12 channels each for a combined bandwidth of 240 kHz 21257. A. Supergroup 21258. B. Group 21259. C. Mastergroup 21260. D. Jumbogroup 21261. 104. The result whenever the sampling rate is less than the twice the highest audio frequency 21262. A. peak limiting 21263. B. overload distortion 21264. C. alias 21265. D. quantizing noise 21266. 105. The most critical and difficult part of receiving a direct-sequence spread spectrum is 21267. A. Frequency synthesis 21268. B. Synchronism 21269. C. PSN code generation 21270. D. Carrier recovery 21271. 106. An FDM hierarchy which is formed by frequency-division multiplexing 10 supergroups together for a combined capacity of 600 voice band message channels 21272. A. Supergroup 21273. B. Group 21274. C. Mastergroup 21275. D. Jumbogroup 21276. 107. It is the transmittal of digital signals between two or more points in a communications system. 21277. A. digital transmittal 21278. B. digitals communications 21279. C. digital radio 21280. D. data communications 21281. 108. It is logically equivalent to making telephone call through the DDD network except no direct end-to-end connection is made 21282. A. Normal call 21283. B. Completed call 21284. C. Logical call 21285. D. Virtual call 21286. 109. It is a proposed network designed by major telephone companies in conjunction with the ITU-T with the intent of providing worldwide telecommunications support for voice, data, video, and facsimile information within the same network. 21287. A. ISDN 21288. B. Broadband communications 21289. C. ATM 21290. D. Ethernet 21291. 110. Full duplex operation 21292. A. requires two pairs of cables 21293. B. can transfer data in both directions at once 21294. C. requires modem at both ends of the circuit 21295. D. all of these 21296. 111. The most widely used data communications code is 21297. A. Morse 21298. B. ASCII 21299. C. Baudot 21300. D. EBCDIC 21301. 112. Ten bit errors in two million transmitted. The bit error rate is −5 21302. A. 2× 10 −5 21303. B. 5×10 −6 21304. C. 5×10 −6 21305. D. 2× 10 21306. 113. It is a type of FSK where the mark and space frequencies are synchronized with the input binary rate 21307. A. QFSK 21308. B. GFSK 21309. C. CPFSK 21310. D. GSK 21311. 114. A form of digital modulation similar to PSK except the digital information is contained in both the amplitude and the phase of the transmitted carrier. 21312. A. ASK 21313. B. FSK 21314. C. QAM 21315. D. PSK 21316. 115. For a 16-PSK and a transmission system with a 10 kHz bandwidth, determine the maximum bit rate 21317. A. 40,000 bps 21318. B. 80,000 bps 21319. C. 20,000 bps 21320. D. 16,000 bps 21321. 116. It is an empirical record of a system’s actual bit error performance. 21322. A. probability of error 21323. B. error detection 21324. C. error control 21325. D. bit error rate 21326. 117. It is a function of the carrier-to-noise power ration and the number of possible encoding conditions used 21327. A. probability of error 21328. B. error detection 21329. C. error control 21330. D. bit error rate 21331. 118. It is used to compare two or more digital modulation systems that use different transmission rates, modulation scheme or encoding techniques 21332. A. Energy per bit-to-noise power density ratio 21333. B. Noise power density 21334. C. power density ratio 21335. D. carrier-to-noise ratio 21336. 119. Indicate which of the following is not a binary code. 21337. A. Morse 21338. B. Baudot 21339. C. CCITT-2 21340. D. ARQ 21341. 120. To permit the selection of 1 out of 16 equiprobable events, the number of bits required is 21342. A. 2 21343. B. log 16 base 10 21344. C. 8 21345. D. 4 21346. 121. The type of modulation most often used with direct-sequence spread spectrum is 21347. A. QAM 21348. B. SSB 21349. C. FSK 21350. D. PSK 21351. 122. Indicate the false statement. In order to combat noise, 21352. A. the channel bandwidth may be increased 21353. B. redundancy may be used 21354. C. the transmitted power may be increased 21355. D. the signaling rate may be reduced 21356. 123. Which of the following is not commonly used method of error detection? 21357. A. Parity 21358. B. BCC 21359. C. CRC 21360. D. redundancy 21361. 124. Quantizing noise occurs in 21362. A. time-division multiplex 21363. B. frequency-division multiplex 21364. C. pulse-code modulation 21365. D. pulse width modulation 21366. 125. In order to reduce quantizing noise, one must 21367. A. increase the number of standard amplitudes 21368. B. send pulses whose sides are more nearly vertical 21369. C. use an RF amplifier in the receiver 21370. D. increase the number of samples per second 21371. 126. Companding is used 21372. A. to overcome quantizing noise in PCM 21373. B. in PCM transmitters, to allow amplitude limiting in the receivers 21374. C. to protect small signals in PCM from quantizing distortion 21375. D. in PCM receivers, to overcome impulse noise 21376. 127. Transmitting data as serial binary words is called _____. 21377. A. digital communications 21378. B. quantizing 21379. C. PAM 21380. D. PCM 21381. 128. Emphasizing low-level signals and compressing higher-level signals is called 21382. A. quantizing 21383. B. companding 21384. C. pre-emphasis 21385. D. sampling 21386. 129. Which circuit is common to both frequency-hopping and direct-sequence spread spectrum transmitters? 21387. A. Correlator 21388. B. Frequency synthesizer 21389. C. PSN code generator 21390. D. Sweep generator 21391. 130. One of the most important aspect of any communication system because it’s costly and limited 21392. A. bandwidth 21393. B. equipments 21394. C. time 21395. D. personnel 21396. 131. It consist essentially of sampling analog information signals and then converting those samples into discreet pulses of transporting the pulses from a source to destination over a physical transmission medium 21397. A. pulse modulation 21398. B. amplitude modulation 21399. C. frequency modulation 21400. D. digital modulation 21401. 132. He is credited with inventing PCM in 1937 21402. A. N.S. Kapany 21403. B. A.H. Reeves 21404. C. E.H. Alpine 21405. D. A.C.S. Van Heel 21406. 133. Data communications uses 21407. A. analog methods 21408. B. digital methods 21409. C. either of these 21410. D. neither of these 21411. 134. An integrated circuit that performs the PCM encoding and decoding functions 21412. A. Codec 21413. B. Modem 21414. C. Muldem 21415. D. Digital-to-analog converter 21416. 135. A synchronous transmission usually begins with which character? 21417. A. SYN 21418. B. STX 21419. C. SOH 21420. D. ETB 21421. 136. A theorem that establishes the minimum sampling rate that can be used for a given PCM systems 21422. A. Nyquist sampling theorem 21423. B. Nyquist minimum bandwidth 21424. C. Nyquist minimum bandwidth 21425. D. Any of these 21426. 137. Sixteen different levels (symbols) are used to encode binary data. The channel bandwidth is 36 MHz. the maximum channel capacity is 21427. A. 187 Mbps 21428. B. 72 Mbps 21429. C. 288 Mbps 21430. D. 2.176 Gbps 21431. 138. Assigning PCM codes to absolute magnitudes 21432. A. Coding 21433. B. Quantizing 21434. C. Sampling 21435. D. Any of these 21436. 139. A popular PC protocol is 21437. A. Parity 21438. B. Xmodem 21439. C. CRC 21440. D. LRC 21441. 140. It is the ratio of the largest possible magnitude to the smallest possible magnitude that can be decoded by the digital-to-analog converter in the receiver 21442. A. Coding efficiency 21443. B. Companding 21444. C. Pre-emphasis 21445. D. Dynamic range 21446. 141. Devices used for digitizing speech signals only 21447. A. codec 21448. B. muldem 21449. C. vocoders 21450. D. modem 21451. 142. What is the minimum bandwidth required to transmit 56 kbps binary signal with no noise? 21452. A. 14 kHz 21453. B. 56 kHz 21454. C. 28 kHz 21455. D. 112 kHz 21456. 143. Type of PCM that uses single-bit PCM code to achieve digital transmission of analog signals 21457. A. Adaptive delta modulation 21458. B. Pulse code modulation 21459. C. Differential modulation 21460. D. Delta modulation 21461. 144. It is a delta modulation system where the step size of the Digital-to-Analog converter is automatically varied, depending on the analog input signal 21462. A. Adaptive delta modulation 21463. B. Pulse code modulation 21464. C. Differential modulation 21465. D. Delta modulation 21466. 145. A QAM modulator does not use _____ 21467. A. XNOR 21468. B. Bit splitter 21469. C. Balanced modulator 21470. D. 2-to-4 level converter 21471. 146. It is a form of phase-division multiplexing where two data channels modulate the same carrier frequency that is shifted 90 degrees in phase. 21472. A. PSK 21473. B. FSK 21474. C. QAM 21475. D. ASK 21476. 147. One eight0bit PCM code is called ______21477. A. FDM frame 21478. B. TDM time slot 21479. C. TDM frame 21480. D. FDM time slot 21481. 148. It is a communication system that uses digital pulse rather than analog signals to encode information 21482. A. Digital carrier system 21483. B. Digital baseband system 21484. C. Digital service system 21485. D. Digital broadband system 21486. 149. A special device that upgrades signals from one level to a higher level of the hierarchy in multiplexing 21487. A. Muldem 21488. B. Vocoder 21489. C. Modem 21490. D. Codec 21491. 150. A transmission of binary data which involves the transmission of only a single non-zero voltage level. 21492. A. Unipolar 21493. B. Polar 21494. C. Bipolar 21495. D. Nonreturn to zero 21496. 151. If the active time of the binary pulse is less than 100% of the bit time 21497. A. Non return to zero 21498. B. Bipolar 21499. C. Unipolar 21500. D. Return to zero 21501. 152. It is a popular type of line encoding that produces a strong timing component for clock recovery and does not cause wandering 21502. A. Digital biphase 21503. B. diphase 21504. C. Manchester code 21505. D. Any of these 21506. 153. Statistical TDMs are also called 21507. A. Intelligent TDMs 21508. B. Asynchronous TDM 21509. C. Stat mux 21510. D. Any of these 21511. 154. A chip that combines the codec and filter functions in the same LSI chip 21512. A. Monolithic 21513. B. Combo chip 21514. C. Film IC 21515. D. Hybrid chip 21516. 155. It is the basic building block of FDM hierarchy 21517. A. Character channel 21518. B. Broadband channel 21519. C. Message channel 21520. D. Information capacity 21521. 156. It is the next higher level in the FDM hierarchy above the basic message channel and consequently is the first multiplexing step for combining message channels 21522. A. Supergroup 21523. B. Group 21524. C. Mastergroup 21525. D. Jumbogroup 21526. 157. It is the modulating signal in a communications system 21527. A. Broadband 21528. B. Baseband 21529. C. Carrier 21530. D. Any of these 21531. 158. What type of mastergroup that can be further multiplexed and used for higher-capacity microwave radio systems? 21532. A. A600 21533. B. U600 21534. C. L600 21535. D. L400 21536. 159. It is essentially the same with FDM, where several signals are transmitted using different carriers, occupying non-overlapping bands of frequency and wavelengths. 21537. A. Time division multiplexing 21538. B. Wave division multiplexing 21539. C. Space division multiplexing 21540. D. Frequency division multiplexing 21541. 160. In order to separate channels in the TDM receiver, it is necessary to use 21542. A. AND gates 21543. B. bandpass filters 21544. C. differentiation 21545. D. integration 21546. 161. To separate channels in an FDM receiver, it is necessary to use 21547. A. AND gates 21548. B. bandpass filters 21549. C. differentiation 21550. D. integration 21551. 162. In FDM, multiple signals 21552. A. transmit at different times 21553. B. share a common bandwidth 21554. C. use multiple channels 21555. D. modulate one another 21556. 163. Frequency modulation in FDM usually accomplished with a 21557. A. reactance modulator 21558. B. varactor 21559. C. VCO 21560. D. PLL 21561. 164. Which of the following is not a common LAN medium? 21562. A. twin lead 21563. B. twisted pair 21564. C. fiber-optic cable 21565. D. coax 21566. 165. A mainframe computer connected to multiple terminals and PCs usually uses which configuration? 21567. A. bus 21568. B. ring 21569. C. star 21570. D. tree 21571. 166. How many voice channels are there in supermaster group? 21572. A. 300 21573. B. 900 21574. C. 3600 21575. D. 10800 21576. 167. In a PAM/TDM system, keeping the multiplexer and DEMUX channels step with one another is done by a 21577. A. clock recovery circuit 21578. B. sync pulse 21579. C. sampling 21580. D. sequencer 21581. 168. It is the process of volume compression before transmission and expansion after detection. 21582. A. pre-emphasis 21583. B. de-emphasis 21584. C. coding 21585. D. companding 21586. 169. Which of the following is correct? 21587. A. The bit rate may be greater than the baud rate 21588. B. The baud rate may be greater than the bit rate 21589. C. The bit and baud rate are always the same 21590. D. The bit and baud rates are not related 21591. 170. Function of data link protocol that coordinates the rate at which data are transported over a link and generally provides an acknowledgement mechanism that ensures that data are received in the destination. 21592. A. Flow control 21593. B. Line discipline 21594. C. Polling 21595. D. Selection 21596. 171. A classification of protocol, which is a discipline for a serial-by-bit information transfer over data communications channel. 21597. A. Message oriented 21598. B. Bit-oriented protocol 21599. C. Clock oriented protocol 21600. D. Asynchronous protocol 21601. 172. A LAN device that interconnects two or more device running identical internetwork protocols. 21602. A. Bridges 21603. B. Gateways 21604. C. Switches 21605. D. Routers 21606. 173. The magnitude of a quantum in quantization of PCM codes. 21607. A. Maximum decodable voltage 21608. B. Dynamic range 21609. C. Resolution 21610. D. Coding level 21611. 174. It comprises of either a single L600 mastergroup or up to three U600 mastergroups 21612. A. Message channel 21613. B. Radio channel 21614. C. Baseband channel 21615. D. Wide channel 21616. 175. It is a multiplexing system similar to conventional time-division multiplexing except that it was developed to be used with optical fibers 21617. A. SONET 21618. B. Frame relay 21619. C. ATM 21620. D. X.25 21621. 176. Higher order TDM levels are obtained by 21622. A. dividing pulse widths 21623. B. using the a-law 21624. C. using u-law 21625. D. forming supermastergroups 21626. 177. Results when the sample exceeds the highest quantization interval 21627. A. Overload distortion 21628. B. Quantization error 21629. C. Quantization noise 21630. D. Granular noise 21631. 178. The event which marked the start of the modern computer age was 21632. A. design of the ENIAC computer 21633. B. development of Hollerith code 21634. C. development of the transistor 21635. D. development of disk drives for data storage 21636. 179. A forward error correcting code corrects errors by 21637. A. requiring partial transmission of the entire signal 21638. B. requiring retransmission of the entire signal 21639. C. requiring no part of the signal to be transmitted 21640. D. using parity to correct the errors in all cases 21641. 180. The carrier used with a BPSK demodulator is 21642. A. Generated by an oscillator 21643. B. The BPSK signal itself 21644. C. Twice the frequency of the transmitted carrier 21645. D. Recovered from the BPSK signal 21646. 181. Digital signals 21647. A. do not provide a continuous set of values 21648. B. represent values as discrete steps 21649. C. can utilize decimal or binary systems 21650. D. all of these 21651. 182. Each signal in an FDM signal 21652. A. modulates the main carrier 21653. B. modulates the final carrier 21654. C. is mixed with all the others before modulation 21655. D. serves as a subcarrier 21656. 183. In digital modulation, if the information signal is digital and the amplitude of the carrier is varied proportional to the information signal. 21657. A. Quartenary Shift Keying (QAM) 21658. B. Phase Shift Keying (PSK) 21659. C. Frequency Shift Keying (FSK) 21660. D. Amplitude Shift Keying (ASK) 21661. 184. Slow speed modems 21662. A. FSK 21663. B. BPSK 21664. C. QPSK 21665. D. QAM 21666. 185. The data rate for IEEE 802.11b is _____. 21667. A. 10 Mbps 21668. B. 1.544 Mbps 21669. C. 2.048 Mbps 21670. D. 11 Mbps 21671. 186. Type of analog companding used in the United States and Japan 21672. A. log-PCM companding 21673. B. A-law companding 21674. C. u-law companding 21675. D. any of these 21676. 187. A rule of procedure that defines how data is to be transmitted is called 21677. A. handshake 21678. B. error-detection 21679. C. data specifications 21680. D. protocol 21681. 188. A longitudinal redundancy check produces 21682. A. block check character 21683. B. parity bit 21684. C. CRC 21685. D. error correction 21686. 189. Multiplexing is the process of 21687. A. Several signal sources transmitting simultaneously to a receiver on common frequency 21688. B. Sending the same signal over multiple channels to multiple destinations 21689. C. Transmitting multiple signals over multiple channels 21690. D. Sending multiple signals simultaneously over a single channel 21691. 190. What is the relationship of bit rate and baud in QPSK and 8-PSK? 21692. A. bit rate is greater than baud 21693. B. bit rate is always less than the baud 21694. C. bit rate is never greater than the baud 21695. D. bit rate is slightly less than the baud 21696. 191. A common method of achieving carrier recovery for BPSK 21697. A. Trellis code 21698. B. Bandwidth efficiency 21699. C. Squaring loop 21700. D. Carrier recovery 21701. 192. What is the relationship of bit rate and baud in FSK and PSK? 21702. A. greater than 21703. B. slightly greater than 21704. C. less than 21705. D. equal 21706. 193. The modulation used in FDM telephone system is 21707. A. AM 21708. B. FM 21709. C. SSB 21710. D. PSK 21711. 194. In digital modulation, a diagram which is similar to phasor diagram except that the entire phasor is not drawn and only the peaks of the phasor are shown 21712. A. constellation diagram 21713. B. Venn diagram 21714. C. phasor diagram 21715. D. schematic diagram 21716. 195. Digital signals may be transmitted over the telephone network if 21717. A. their speed is low enough 21718. B. they are converted to analog first 21719. C. they are ac instead of dc 21720. D. they are digital only 21721. 196. Most FDM telemetry system use 21722. A. AM 21723. B. FM 21724. C. SSB 21725. D. PSK 21726. 197. In TDM, multiple signals 21727. A. share a common bandwidth 21728. B. modulate subcarriers 21729. C. are sampled at high speeds 21730. D. take turns transmitting 21731. 198. It is highly theoretical study of efficient use of bandwidth to propagate information through electronic communications system 21732. A. information capacity 21733. B. data communications 21734. C. information theory 21735. D. information technology 21736. 199. Another name for parity is 21737. A. Vertical redundancy check 21738. B. Block check character 21739. C. Longitudinal redundancy check 21740. D. Cyclic redundancy check 21741. 200. It is the process of gathering data on some particular phenomenon without the presesnce of human monitors 21742. A. Telemetry 21743. B. Telecommand 21744. C. Telecommunications 21745. D. Remote control 21746. 201. A convenient technique for determining the effects of the degradations introduced into the pulses as they travel to the regenerator. 21747. A. Standing wave ratio 21748. B. Eye patterns 21749. C. Reflection coefficient 21750. D. Any of these 21751. 202. Spread spectrum stations sharing a band are identified by and distinguished from one another 21752. A. PSN code 21753. B. Frequency of operation 21754. C. Clock rate 21755. D. Modulation type 21756. 203. The ASCII code has 21757. A. 4 bits 21758. B. 5 bits 21759. C. 7 bits 21760. D. 8 bits 21761. 204. The first file transfer protocol designed to facilitate transferring data between two personal computers over the public switched telephone network 21762. A. X modem protocol 21763. B. Y modem protocol 21764. C. Z modem protocol 21765. D. BLAST 21766. 205. For a single-channel PCM system with a sample rate of 6000 samples per second and a seven-bit compressed PCM code, what is the line speed? 21767. A. 21,000 bps 21768. B. 42,000 bps 21769. C. 14,000 bps 21770. D. 12,000 bps 21771. 206. It is often used to compare the performance of one digital modulation technique to another 21772. A. Bandwidth efficiency 21773. B. Spectral efficiency 21774. C. Information density 21775. D. All of these 21776. 207. It is the process of extracting a phase-coherent reference carrier from a receiver signal 21777. A. Phase referencing 21778. B. Trellis code 21779. C. Squaring loop 21780. D. any of these 21781. 208. It is the measure of how much information can be propagated through a communication system and is a function of a bandwidth of the transmission line 21782. A. information theory 21783. B. information capacity 21784. C. information technology 21785. D. digital communications 21786. 209. In delta modulation, the modulator is sometimes called _____. 21787. A. continuous ADC 21788. B. tracking ADC 21789. C. variable slope ADC 21790. D. slope ADC 21791. 210. The code which provides for parity checks is 21792. A. Baudot 21793. B. ASCII 21794. C. CCITT-2 21795. D. EBCDIC 21796. 211. Form of multiplexing that constitutes propagating signals from different cables that sre contained within the same trench 21797. A. Wavelength division multiplexing 21798. B. Wave division multiplexing 21799. C. Space division multiplexing 21800. D. Frequency division multiplexing 21801. 212. For an 8-PSK system, operating with an information bit rate of 24 kbps, determine the bandwidth efficiency 21802. A. 8 bits/cycle 21803. B. 2 bits/cycle 21804. C. 3 bits/cycle 21805. D. 4 bits/cycle 21806. 213. Element of a PCM system that periodically samples the analog input signal and converts those samples to a multilevel PAM signal 21807. A. Bandpass filter 21808. B. Sample-and-hold circuit 21809. C. Analog-to-digital converter 21810. D. Digital-to-analog converter 21811. 214. It is the ratio of the average carrier power to the thermal noise power 21812. A. Signal-to-noise ratio 21813. B. Noise figure 21814. C. Noise factor 21815. D. Carrier-to-noise ratio 21816. 215. A form of switching which is hold and forward 21817. A. Packet switching 21818. B. Message switching 21819. C. Circuit switching 21820. D. Digital switching 21821. 216. It can be used to categorize the type of transmission 21822. A. Duty cycle 21823. B. Companding 21824. C. Coding efficiency 21825. D. Dynamic range 21826. 217. Type of multiplexing where multiple sources that originally occupied the same frequency spectrum are each converted to a different frequency band and transmitted simultaneously over a single transmission medium. 21827. A. FDM 21828. B. ATM 21829. C. TDM 21830. D. Spread spectrum 21831. 218. It is a solicitation sent from the primary to a secondary to determine if the secondary has data to transmit 21832. A. Selection 21833. B. Polling 21834. C. Error control 21835. D. Master control 21836. 219. Function of data link control that specifies the means of detecting and correcting transmission errors 21837. A. Error control 21838. B. Selection 21839. C. Protocol 21840. D. Synchronization 21841. 220. The Hartley law states that 21842. A. the maximum rate of information transmission depends on the channel bandwidth 21843. B. the maximum rate of information depends on the depth of modulation 21844. C. redundancy is essential 21845. D. only binary codes may be used 21846. 221. It represents the number of independent symbols that can be carried through a system in a given unit of time. 21847. A. information theory 21848. B. information capacity 21849. C. information technology 21850. D. digital communications 21851. 222. The Shannon-Hartley law 21852. A. refers to distortion 21853. B. defines the bandwidth 21854. C. describes signaling rates 21855. D. refers to noise 21856. 223. The most basic digital symbol used to represent information 21857. A. bit 21858. B. baud 21859. C. bits per second 21860. D. any of these 21861. 224. Function of data link protocol that coordinates hop-to-hop data delivery where a hop maybe a computer, a network controller or a network-connecting device such as router. 21862. A. Flow control 21863. B. Error control 21864. C. Line discipline 21865. D. Selection 21866. 225. Quadrature amplitude modulation is 21867. A. Amplitude modulation only 21868. B. QPSK only 21869. C. AM plus QPSK 21870. D. AM plus FSK 21871. 226. The most common modulation system used for telegraphy is 21872. A. frequency-shift keying 21873. B. two-tone modulation 21874. C. pulse-code modulation 21875. D. single-tone modulation 21876. 227. It is used to encode the minimum amount of speech information necessary to reproduce a perceptible message with a fewer bits that those needed by a conventional encoder/decoder 21877. A. codec 21878. B. muldem 21879. C. vocoders 21880. D. modem 21881. 228. It is the transmission of information in any form from one source to one or more destination 21882. A. Modulation 21883. B. Multiplexing 21884. C. Encoding 21885. D. Decoding 21886. 229. A form of switching which is stored and forward 21887. A. Packet switching 21888. B. Message switching 21889. C. Circuit switching 21890. D. Digital switching 21891. 230. In digital modulation, it is similar to standard amplitude modulation except there is only two amplitudes possible 21892. A. frequency shift keying 21893. B. quartenary amplitude modulation 21894. C. amplitude shift keying 21895. D. phase shift keying 21896. 231. The technique of using modulation and FDM to transmit multiple data channels of a common medium is known as 21897. A. baseband 21898. B. broadband 21899. C. ring 21900. D. bus 21901. 232. Which of the following is not a benefit of companding 21902. A. minimizes noise 21903. B. minimizes number of bits 21904. C. minimizes quantizing error 21905. D. minimizes signal bandwidth 21906. 233. Transmissions from multiple sources occur in the same facility but not at the same time 21907. A. Time Division Multiplexing 21908. B. Frequency Division Multiplexing 21909. C. Wave Division Multiplexing 21910. D. Space Division Multiplexing 21911. 234. A 9600-baud rate signal can pass over the voice grade telephone line if which kind of modulation is used? 21912. A. BPSK 21913. B. QPSK 21914. C. DPSK 21915. D. QAM 21916. 235. Indicate which of the following pulse modulation systems is analog 21917. A. PCM 21918. B. PWM 21919. C. Differential PCM 21920. D. Delta 21921. 236. The modulation system inherently most noise-resistant is 21922. A. SSB, suppressed carrier 21923. B. frequency modulation 21924. C. pulse-position modulation 21925. D. pulse-code modulation 21926. 237. It is simply the number of bits transmitted during one second and expressed in bits per second 21927. A. baud 21928. B. bits 21929. C. bit rate 21930. D. pulse repetition rate 21931. 238. It is the most prevalent encoding technique used for TDM signals 21932. A. PAM 21933. B. PLM 21934. C. PPM 21935. D. PCM 21936. 239. The characters making up the message in a synchronous transmission are collectively referred to as the data 21937. A. set 21938. B. sequence 21939. C. block 21940. D. collection 21941. 240. A virtual circuit which is logically equivalent to a two-point dedicated private-line circuit except slower 21942. A. Switched Virtual Circuit 21943. B. Permanent Virtual Circuit 21944. C. Switched Leased Circuit 21945. D. Permanent Leased Circuit 21946. 241. To a conventional narrowband receiver, a spread spectrum signal appears to be like 21947. A. Noise 21948. B. Fading 21949. C. A jamming signal 21950. D. An intermittent connection 21951. 242. It is a low-quality video transmission for use between non-dedicated subscribers 21952. A. Digital phone 21953. B. Picturephone 21954. C. Cameraphone 21955. D. Cellphone with camera 21956. 243. Pulse code modulation is preferred to PAM because of its 21957. A. resistance to quantizing errror 21958. B. simplicity 21959. C. lower cost 21960. D. superior noise immunity 21961. 244. A CRC generator uses which component? 21962. A. balanced modulator 21963. B. shift register 21964. C. binary adder 21965. D. multiplexer 21966. 245. A signaling element is sometimes called 21967. A. information 21968. B. data 21969. C. symbol 21970. D. intelligence 21971. 246. Which of the following words has the correct parity bit? Assume odd parity. The last bit is the parity bit. 21972. A. 1111111 1 21973. B. 1100110 1 21974. C. 0011010 1 21975. D. 0000000 0 21976. 247. It is a digital interface that provides the physical connection to the digital carrier network 21977. A. Modem 21978. B. Codec 21979. C. Muldem 21980. D. DSU/CSU 21981. 248. It is the only digitally encoded modulation technique that is commonly used for digital transmission 21982. A. PAM 21983. B. PCM 21984. C. PLM 21985. D. PPM 21986. 249. The most common circuit used for demodulating binary FSK signals 21987. A. phase locked loop 21988. B. Foster-Seeley discriminator 21989. C. varactor 21990. D. phase shift method 21991. 250. A digital modulation technique also known as “on-off” keying 21992. A. PSK 21993. B. FSK 21994. C. QUAM 21995. D. OOK 21996. 21997. 21998. 21999. 22000. 22001. 22002. 22003. 22004. 22005. MULTIPLE CHOICE QUESTIONS IN 22006. MISCELLANEOUS TOPICS 22007. Electronics Systems and Technologies 22008. By 22009. Melvin C. Arceo 22010. 22011. 22012. 22013. 22014. 22015. 22016. 22017. 22018. 22019. 22020. ENCODED BY: 22021. GIRAO, Edward Joseph D. 22022. 1. It is the provision of voice communication using Internet Protocol (IP) technology, instead of traditional circuit switched technology 22023. A. VOIP 22024. B. Bluetooth 22025. C. WIFI 22026. D. WIMAX 22027. 2. Bluetooth enabled electronic devices connect and communicate wirelessly through short-range, ad hoc networks known as _____. 22028. A. nanonet 22029. B. scatternet 22030. C. piconet 22031. D. netnet 22032. 3. Each device can simultaneously communicate with up to ______other devices with a single piconet. 22033. A. 8 22034. B. 5 22035. C. 10 22036. D. 7 22037. 4. The core specification version of Bluetooth that uses Enhanced Data Rate (EDR) 22038. A. Version 1.0 22039. B. Version 2.0 22040. C. Version 1.2 22041. D. Version 2.1 22042. 5. Bluetooth technology operates in the _____ band. 22043. A. ISM 22044. B. C band 22045. C. MSI 22046. D. Ku band 22047. 6. Bluetooth technology operates in the band 22048. A. 2.4 to 2.485 GHz 22049. B. 2.42 to 2.44 GHz 22050. C. 2.48 to 2.52 GHz 22051. D. 2.3 to 2.45 GHz 22052. 7. The hopping rate of Bluetooth is 22053. A. 1000 hops/sec 22054. B. 1600 hops/sec 22055. C. 1500 hops/sec 22056. D. 2500 hops/sec 22057. 8. Technology used by Bluetooth designed to reduce interference between wireless technologies sharing the 2.4 GHz spectrum 22058. A. AFH 22059. B. DSSS 22060. C. OFDM 22061. D. FHSS 22062. 9. The signal hops among ______frequencies at 1 MHz intervals to give a high degree of interference immunity 22063. A. 80 22064. B. 78 22065. C. 81 22066. D. 79 22067. 10. Class 3 radios used for Bluetooth technology have a range of up to 22068. A. 1 ft 22069. B. 2 ft 22070. C. 3 ft 22071. D. 4 ft 22072. 11. Class 2 radios used for Bluetooth most commonly found in mobile devices have a range of ______. 22073. A. 10 ft 22074. B. 20 ft 22075. C. 15 ft 22076. D. 30 ft 22077. 12. Class 1 radios used primarily in industrial use cases have a range of 22078. A. 100 meters 22079. B. 25 meters 22080. C. 10 meters 22081. D. 50 meters 22082. 13. Bluetooth technology uses ______of power. 22083. A. 2.6 mW 22084. B. 2.5 mW 22085. C. 2,8 mW 22086. D. 2.7 mW 22087. 14. What is the data rate used by Bluetooth technology using version 1.2 specification? 22088. A. 1 Mbps 22089. B. 2 Mbps 22090. C. 3 Mbps 22091. D. 4 Mbps 22092. 15. What is the data rate used by Bluetooth technology using version 2.0 + EDR specification? 22093. A. 1 Mbps 22094. B. 3 Mbps 22095. C. 2 Mbps 22096. D. 4 Mbps 22097. 16. Bluetooth technology has built-in security such as _____ bit encryption 22098. A. 64 22099. B. 16 22100. C. 32 22101. D. 128 22102. 17. The symbol rate for Bluetooth is 22103. A. 1 Mega symbol per sec 22104. B. 3 Mega symbol per sec 22105. C. 2 Mega symbol per sec 22106. D. 4 Mega symbol per sec 22107. 18. In satellite communications, for an angle of inclination 0f 63.4 degrees, the rotation of the line of apsides is ____ degrees 22108. A. 0 22109. B. 5 22110. C. 15 22111. D. 3 22112. 19. An international agreement initially mandated that all satellites placed in the Clarke or Geosynchronous orbit must be separated by at least 22113. A. 22,300 mi 22114. B. 3400 mi 22115. C. 1833 mi 22116. D. 5544 mi 22117. 20. The radiation pattern of earth coverage antennas of satellites have a beamwidth of approximately ______. 22118. A. 15 degrees 22119. B. 17 degrees 22120. C. 10 degrees 22121. D. 11 degrees 22122. 21. ______is a new nonvoice value added service that allows information to be sent and received across a mobile telephone network. 22123. A. WiFi 22124. B. Wimax 22125. C. GPRS 22126. D. HSCSD 22127. 22. Theoretical maximum speeds of up to _____ kbps are achievable with GPRS using all _____ timeslots at the same time. 22128. A. 64, 8 22129. B. 171.2, 8 22130. C. 128, 7 22131. D. 183.5, 7 22132. 23. It is the latest standard of MPEG under development that will support download and execution of multimedia applications. 22133. A. MPEG-21 22134. B. MPEG-A 22135. C. MPEG-7 22136. D. MPEG-E 22137. 24. A new standard line of MPEG standard called multimedia application format is _____. 22138. A. MPEG-A 22139. B. MPEG-C 22140. C. MPEG-B 22141. D. MPEG-D 22142. 25. MPEG standard on which such products as Digital Television set top boxes and DVD are based 22143. A. MPEG-1 22144. B. MPEG-4 22145. C. MPEG-2 22146. D. MPEG-7 22147. 26. MPEG standard on which such products as Video CD and MP3 are based 22148. A. MPEG-1 22149. B. MPEG-7 22150. C. MPEG-21 22151. D. MPEG-3 22152. 27. MPEG standard for multimedia for the fixed and mobile web 22153. A. MPEG-1 22154. B. MPEG-4 22155. C. MPEG-2 22156. D. MPEG-7 22157. 28. MPEG standard for description and search of audio and visual content. 22158. A. MPEG-1 22159. B. MPEG-7 22160. C. MPEG-21 22161. D. MPEG-3 22162. 29. The MPEG standard for the Multimedia Framework 22163. A. M3W 22164. B. MPEG-4 22165. C. MPEG-7 22166. D. MPEG-21 22167. 30. Coding of moving pictures and associated audio for digital storage media at up to about 1.5 Mbps. 22168. A. MPEG-3 22169. B. MPEG-2 22170. C. MPEG-4 22171. D. MPEG-1 22172. 31. Used in MPEG to remove spatial correlation. 22173. A. Discrete Shine Transform 22174. B. Discreet Cosine Transform 22175. C. Discreet Secant Transform 22176. D. Discreet Cosecant Transform 22177. 32. MPEG-4 builds on the proven success on one of the following fields 22178. A. Digital television 22179. B. Interactive multimedia 22180. C. Interactive graphics applications 22181. D. Any of these 22182. 33. The maximum effective power allowed for RFID is _____. 22183. A. 0.5 watt 22184. B. 3 watts 22185. C. 1 watt 22186. D. 0.25 watt 22187. 34. The use and operation of RFIDs shall be allowed in the following frequency bands except: 22188. A. 13.533-13.567 MHz 22189. B. 2446-2454 MHz 22190. C. 918-920 MHz 22191. D. 254-365 MHz 22192. 35. _____ are radio systems based on local area networking solutions that require higher data rates and consequently greater bandwidth for new multimedia applications spectrum requirements 22193. A. WIFI 22194. B. HiperLAN 22195. C. WIMAX 22196. D. VOIP 22197. 36. _____ refers to the determination of the position, velocity and/or other characteristics of an object, or the obtaining of information relating to these parameters, by means of the propagation properties of radio waves. 22198. A. position determination 22199. B. radio determination 22200. C. velocity determination 22201. D. range determination 22202. 37. Radio microphones has power of _____ mW or less. 22203. A. 20 22204. B. 40 22205. C. 30 22206. D. 50 22207. 38. _____ referred to as wireless microphones or cordless microphones, are small, low power, unidirectional transmitters designed to be worn on the body, or hand held, for the transmission of sound over short distances for personal use. 22208. A. directional microphone 22209. B. parabolic microphone 22210. C. radio microphone 22211. D. spy microphone 22212. 39. _____ are intended to carry data in suitable transporters, generally known as tags, and to retrieve data, by hand- or manine-readable means, at a suitable time and place to satisfy particular application needs. 22213. A. RFID 22214. B. HiperLan 22215. C. transponder tags 22216. D. bluetooth 22217. 40. _____ also referred to as dedicated short-range communications for transport information and control systems are systems providing data communication between two or more road vehicles and between road vehicles and the road infrastructure for various information-based travel and transport applications, including automatic toll-collection, route and parking guidance, collision avoidance and similar applications. 22218. A. RTTY 22219. B. TICS 22220. C. RTTT 22221. D. RSSD 22222. 41. _____ for use with implanted medical devices, like pacemakers, implantable defibrillators, nerve stimulators, and other types of implanted devices. 22223. A. MICS 22224. B. TICS 22225. C. AIDS 22226. D. PACER 22227. 42. What is the frequency band for biomedical devices? 22228. A. 40.66-40.70 MHz 22229. B. 13.90-14.40 MHz 22230. C. 50.44-51.09 MHz 22231. D. 32.10-33.89 MHz 22232. 43. The electric field intensity of biomedical devices? 22233. A. 1000 µV/m at 3m 22234. B. 10 µV/m at 3m 22235. C. 100 µV/m at 3m 22236. D. 1 µV/m at 3m 22237. 44. _____ refers to the use of radio communication devices for the transmission of signals to initiate, modify or terminate functions of equipment at a distance. 22238. A. telemetry 22239. B. wireless application 22240. C. telecommand 22241. D. radio beacon 22242. 45. The data rate used by IEEE 802.11b 22243. A. 11 Mbps 22244. B. 55 Mbps 22245. C. 54 Mbps 22246. D. 12 Mbps 22247. 46. The operating frequency of IEEE 802.11b 22248. A. 2.4 GHz 22249. B. 5.5 GHz 22250. C. 5 GHz 22251. D. 2.5 GHz 22252. 47. The operating frequency of IEEE 802.11a 22253. A. 2.5 GHz 22254. B. 5 GHz 22255. C. 5.5 GHz 22256. D. 2.1 GHz 22257. 48. The data rate of IEEE 802.11a 22258. A. 55 Mbps 22259. B. 53 Mbps 22260. C. 54 Mbps 22261. D. 50 Mbps 22262. 49. _____ is a standards-based wireless technology that provides high-throughput broadband connections over long distances. 22263. A. Wimax 22264. B. Wibro 22265. C. Wifi 22266. D. Winar 22267. 50. _____ is a wireless broadband technology being developed by the Korean telecoms industry. 22268. A. Wimax 22269. B. Wibro 22270. C. Wifi 22271. D. Winar 22272. 51. What is the operating frequency of Wibro? 22273. A. 2.1 GHz 22274. B. 2.3 GHz 22275. C. 2.2 GHz 22276. D. 2.4 GHz 22277. 52. What is the base station data throughout for Wibro? 22278. A. 30 to 50 Mbps 22279. B. 40 to 60 Mbps 22280. C. 50 to 70 Mbps 22281. D. 60 to 80 Mbps 22282. 53. The maximum radius for Wibro is ____. 22283. A. 2 km 22284. B. 3 km 22285. C. 4 km 22286. D. 5 km 22287. 54. _____ is a published specification set of high level communication protocols designed to use small, low-power digital radios based on the IEEE 802.15.4 standard for wireless personal area networks. 22288. A. bluetooth 22289. B. wpan 22290. C. zigbee 22291. D. wlan 22292. 55. In a Zigbee network, a single device that controls the network is called _____. 22293. A. master 22294. B. server 22295. C. coordinator 22296. D. pointer 22297. 56. Devices being controlled in a zigbee network are known as _____. 22298. A. end devices 22299. B. clients 22300. C. slaves 22301. D. beggars 22302. 57. The modulation scheme used by IEEE 802.11b 22303. A. OFDM 22304. B. CCK 22305. C. QPSK 22306. D. FDM 22307. 58. The modulation scheme used by IEEE 802.11a 22308. A. OFDM 22309. B. CCK 22310. C. QPSK 22311. D. FDM 22312. 59. The World Wide Web or WWW was invented in the year _____. 22313. A. 1991 22314. B. 1990 22315. C. 1989 22316. D. 1995 22317. 60. He invented the World Wide Web or WWW 22318. A. Karel Capek 22319. B. Tim Berners-Lee 22320. C. Jon Von Neumann 22321. D. Bill Gates 22322. 61. The number of satellites used by GLONASS 22323. A. 30 22324. B. 26 22325. C. 24 22326. D. 31 22327. 62. A 3G technology that delivers broadband-like data speeds to mobile devices. 22328. A. EDGE 22329. B. HSCSD 22330. C. VOIP 22331. D. 3GSM 22332. 63. ADSL has maximum distance of _____. 22333. A. 16,000 feet 22334. B. 8,000 feet 22335. C. 18,000 feet 22336. D. 12,000 feet 22337. 64. ______is an implementation of ADSL that automatically adjusts the connection speed to adjust for the quality of the telephone line. 22338. A. ADSL 22339. B. SDSL 22340. C. RADSL 22341. D. HDSL 22342. 65. A type of DSL that was developed to support exceptionally high-bandwidth applications such as High-Definition Television (HDTV). 22343. A. VDSL 22344. B. SDSL 22345. C. ADSL 22346. D. XDSL 22347. 66. A method for moving data over regular phone lines which is much faster than a regular phone connection and the wires coming into the subscriber’s premises are the same copper wires used for regular phone service. 22348. A. VOIP 22349. B. DSL 22350. C. Cable Internet 22351. D. POTS 22352. 67. What is the IEEE designation for Bluetooth? 22353. A. 802.15 22354. B. 802.14 22355. C. 802.10 22356. D. 802.16 22357. 68. The IEEE designation for wireless LAN 22358. A. 802.12 22359. B. 802.13 22360. C. 802.5 22361. D. 802.11 22362. 69. The IEEE designation for broadband wireless network 22363. A. 802.16 22364. B. 802.15 22365. C. 802.14 22366. D. 802.13 22367. 70. The file extension for jpeg 22368. A. .jpg 22369. B. .jpe 22370. C. .jfif 22371. D. any of these 22372. 71. In SMS, the number of characters being sent in the network is _____ when Latin alphabet is used. 22373. A. 80 22374. B. 160 22375. C. 65 22376. D. 100 22377. 72. In SMS, the number of characters being sent in the network is _____ when non-Latin alphabet is used. 22378. A. 50 22379. B. 60 22380. C. 70 22381. D. 80 22382. 73. It is an enhancement of data services of all current GSM networks, it allows you to access nonvoice services at 3 times faster 22383. A. GPRS 22384. B. HSCSD 22385. C. VOIP 22386. D. 3GSM 22387. 74. A language derived from HTML especially for wireless network characteristics. 22388. A. Delphi 22389. B. PHP 22390. C. Pearl 22391. D. WML 22392. 75. The founding father of the Internet 22393. A. Tim Burners-Lee 22394. B. Vinton Gray Cerf 22395. C. Jon Von Neumann 22396. D. Carel Kapek 22397. 76. What term is used by in asynchronous transfer mode (ATM) system to describe a byte? 22398. A. harmonic 22399. B. octet 22400. C. actave 22401. D. bit 22402. 77. The relative permittivity of silicon is _____ 22403. A. 11.7 22404. B. 1.17 22405. C. 1.18 22406. D. 11.8 22407. 78. One of the following is NOT classified as a Customer Premises Equipment (CPE) by the NTC. 22408. A. Automatic Teller Machine 22409. B. Videophone Terminal Equipment 22410. C. VSAT 22411. D. ISDN Terminal Equipment 22412. 79. Zigbee network layer supports the following topologies except: 22413. A. tree 22414. B. bus 22415. C. star 22416. D. mesh 22417. 80. An Internet Messaging service can be either _____. 22418. A. user-based or company based 22419. B. sender-based or receiver based 22420. C. network-based or device-based 22421. D. feature-based or attachment-based 22422. 81. The level of ____ within an IM program brings up the issue of privacy. 22423. A. users signed up 22424. B. advertising 22425. C. technology 22426. D. presence awareness 22427. 82. One reason behind the success of the Internet is the fact that it is built on _____. 22428. A. open standard 22429. B. user trust 22430. C. safe architecture 22431. D. solid ground 22432. 83. Which of the following is not an additional revenue opportunity offered by advance messaging services? 22433. A. electronic commerce 22434. B. advertising 22435. C. targeted marketing 22436. D. taxes 22437. 84. ADSL increases existing twisted-pair access capacity by _____. 22438. A. twofold 22439. B. threefold 22440. C. thirtyfold 22441. D. fiftyfold 22442. 85. What appears to be the practical limit for analog modems over a standard telephone? 22443. A. 33 kbps 22444. B. 28.8 kbps 22445. C. 24 kbps 22446. D. 19.2 kbps 22447. 86. Which of the parameters will need to be incorporated into next generation billing solutions to calculate new 3G charges? 22448. A. number of packets 22449. B. location 22450. C. quality of service 22451. D. any of these 22452. 87. Which of the following is not considered as 3G service? 22453. A. streaming video 22454. B. wireless voice 22455. C. interactive shopping 22456. D. on-line banking and stock trading 22457. 88. ATM timing requirements feature _____ elements. 22458. A. 3 22459. B. 4 22460. C. 32 22461. D. 64 22462. 89. All are required for broadband media services delivery over IP except: 22463. A. high bandwidth 22464. B. a broadband connection 22465. C. a narrowband connection 22466. D. DSL 22467. 90. All are network components for broadband media services except 22468. A. video server 22469. B. catv box 22470. C. set-top box 22471. D. video encoder 22472. 91. A Cable Modem Termination System (CMTS) provides an Ethernet network with a geographic reach of up to _____. 22473. A. 1 mile 22474. B. 10 miles 22475. C. 100 miles 22476. D. any of these 22477. 92. The upstream data channel specification requirement for cable modem feature which of the following? 22478. A. 64 and 256 QAM formats 22479. B. data rates from 320 kbps to 10 Mbps 22480. C. 6 MHz-occupied spectrum that coexists with other signals in the cable plant 22481. D. all of the above 22482. 93. DWDM enables different formats, such as ______, to be transmitted over the optical layer. 22483. A. IP and ATM 22484. B. ATM and SONET 22485. C. SONET and SDH 22486. D. all of the above 22487. 94. Future DWDM terminals will have the capacity to transmit _____ volumes of an encyclopedia in one second. 22488. A. 90 22489. B. 250 22490. C. 1500 22491. D. 90000 22492. 95. DWDM allows the transmission of _____ over the optical layer. 22493. A. voice and e-mail 22494. B. multimedia and video 22495. C. data 22496. D. all of the above 22497. 96. Which of the following is expected to take the largest share of the three DSL varieties? 22498. A. SDSL 22499. B. HDSL 22500. C. ADSL 22501. D. IDSL 22502. 97. Which of the following standards defines procedures and message sequences used for fax communications? 22503. A. T.10 22504. B. T.30 22505. C. T.37 22506. D. T.38 22507. 98. The _____ is a particular set of standards that allows the internetworking of products from different vendors. It usually embodies a fiber-optic ring that will permit transmission in both directions. 22508. A. local-area network (LAN) 22509. B. wide-area network (WAN) 22510. C. synchronous optical network (SONET) 22511. D. common channel signaling network 22512. 99. H.255 can be defined as _____. 22513. A. media stream control 22514. B. control signaling 22515. C. call signaling 22516. D. media stream transport 22517. 100. H.245 can be defined as _____. 22518. A. media stream control 22519. B. control signaling 22520. C. media stream transport 22521. D. registration and admission 22522. 101. H.323 can be defined as _____. 22523. A. multimedia services over B-ISDN 22524. B. multimedia services over guaranteed QoS networks 22525. C. multimedia services over packet networks 22526. D. multimedia services over SCN 22527. 102. H.320 can be defined as _____. 22528. A. multimedia services over B-ISDN 22529. B. multimedia services over guaranteed QoS networks 22530. C. multimedia services over packet networks 22531. D. multimedia services over ISDN 22532. 103. One of the major advances that result from implementing intelligent networks is that _____. 22533. A. computers no longer have control over the network 22534. B. wide-area service outages are much less likely 22535. C. services can be adapted to user needs more efficiently 22536. D. service providers are now limited to a single equipment provider 22537. 104. The development of the intelligent network places increased emphasis on a consistent _____. 22538. A. switch model 22539. B. network model 22540. C. intelligence model 22541. D. call model 22542. 105. How many layers are there to the PCS air resistance? 22543. A. 1 22544. B. 2 22545. C. 3 22546. D. 4 22547. 106. What is the maximum possible number of characters in a PCS message? 22548. A. 64 22549. B. 256 22550. C. 1021 22551. D. 239 22552. 107. Signaling units are broken up into units of how many bits? 22553. A. 8 22554. B. 16 22555. C. 32 22556. D. 64 22557. 108. Two digital signals whose transitions occur at almost the same rate are _____. 22558. A. asynchronous 22559. B. synchronous 22560. C. plesiochronous 22561. D. none of these 22562. 109. Which of the following are not basic SONET network elements? 22563. A. switch interference 22564. B. digital loop carrier 22565. C. service control point 22566. D. add/drop multiplexer 22567. 110. Higher-order SDH cross-connects route what entity? 22568. A. 1.5 Mbps 22569. B. ATM cells 22570. C. management data channels 22571. D. payload within 155 Mbps 22572. 111. Scrambling is used in SDH for which reason? 22573. A. to randomize the bit sequence for better transmission performance 22574. B. to reduce the power consumption of equipment 22575. C. to allow for upgrade to higher bit rates 22576. D. to prevent unauthorized access 22577. 112. FDMA allocated ____ users per channel. 22578. A. 1 22579. B. 3 22580. C. 6 22581. D. 10 22582. 113. The G.723.1 specification for audio codecs, recommended by the VoIP Forum, requires: 22583. A. 6.3 kbps 22584. B. 7.9 kbps 22585. C. 8.4 kbps 22586. D. 10.4 kbps 22587. 114. ITU’s H.320 standard defines the protocols for transporting voice, data and video over; 22588. A. PSTN 22589. B. ISDN networks 22590. C. the public internet 22591. D. GSM network 22592. 115. Which of the following is not a layer in the WAP gateway stack? 22593. A. WDP 22594. B. context manager 22595. C. TCP 22596. D. WSP 22597. 116. Queries to the HLR are performed to find the location of the serving MSC in _____. 22598. A. TDMA 22599. B. CDMA 22600. C. GSM 22601. D. all of the above 22602. 117. The SMSC delivers messages directly to the _____. 22603. A. HLR 22604. B. VLR 22605. C. MSC 22606. D. BSC 22607. 118. Which of the following pairs of technologies use IS-41? 22608. A. GSM and TDMA 22609. B. CDMA and GSM 22610. C. TDMA and CDMA 22611. D. all of the above 22612. 119. Which of the following technologies has significant advantages in medium- density and high-density population areas because it is capable of carrying higher levels of traffic, provides better voice quality, and can transmit data at higher rates? 22613. A. GSM 22614. B. PCS 22615. C. CT-2 22616. D. DECT 22617. 120. IS-41 is a standard currently being embraced by wireless providers because it encourages _____. 22618. A. increased network capabilities 22619. B. paging 22620. C. roaming 22621. D. all of the above 22622. 22623. 22624. 22625. 22626. 22627. 22628. 22629. 22630. 22631. 22632. 22633. 22634. 22635. 22636. 22637. 22638. 22639. 22640. 22641. 22642. 22643. MULTIPLE CHOICE QUESTIONS IN 22644. CELLULAR TELEPHONY 22645. Electronics Systems and Technologies 22646. By 22647. Melvin C. Arceo 22648. 22649. 22650. 22651. 22652. 22653. 22654. 22655. 22656. 22657. 22658. ENCODED BY: 22659. LAQUI, Louise Ruelyn J. 22660. Base station transmitter output power of Improved Mobile System (IMTS) 22661. 22662. A.100-W to 200-W range 22663. B. 200-W to 300-W range 22664. C. 150-W to 400-W range 22665. D. 300-W to 400-W range 22666. 22667. The chipping rate of WCDMA (UMTS) 22668. 22669. A. 3.84 Mcps 22670. B. 3.6484 Mcps 22671. C. 1.25 Mcps 22672. D. 1.22 Mcps 22673. 22674. A technique that divides the group of channels into smaller groupings or segments of mutually exclusive frequencies; cell sites, which are within the reuse distance is assigned their own segment of the channel group 22675. sectoring dualization partitioning segmentation 22676. 22677. The actual voice channel where mobile users communicate directly with other mobile or wireline subscriber through the base station 22678. control channel forward channel reverse channel voice channel 22679. 22680. Supervisory Audio Tones(SAT) have the following frequencies except: 22681. 5940 Hz 5970 Hz 6000 Hz 6030 Hz 22682. 22683. Each cell site contains a 22684. Repeater Control computer Direct-link to a branch exchange Touch-tone processor 22685. 22686. A class II mobile phone using AMPS has an ERP of 22687. -6dBW -4dBW 2dBW 6dBW 22688. 22689. The wideband designation in Wideband-CDMA (WCDMA) denotes a bandwidth of 22690. 2.5 MHz 3 MHz 4.5 MHz 5MHz 22691. 22692. An automobile travels at 60km/hr. Find the time between fades in the car uses a PCS phone at 1900 MHz. 22693. 2.4 ms 3.4 ms 4.7 ms 5.1 ms 22694. 22695. A cellular system is capable of coping with handoffs once every 2 minutes. Suppose this system is in the city with maximum car speeds of 65km/hr. What is the maximum cell radius for this urban system? 22696. 1.08 km 3 km 5 km 2 km 22697. 22698. How wide is the spectrum bandwidth of a single GSM carrier? 22699. 16 kHz 200 kHz 100 kHz 50 kHz 22700. 22701. Changing the time order of digital information before transmission to reduce the effect of burst errors in the channel. 22702. progression interleaving epoch raking 22703. 22704. The bandwidth of WCDMA is ___ times larger than GSM. 22705. 5 15 20 25 22706. 22707. It is the process in which the same set of frequencies can be allocated to more than one cell, provided that the cells are separated by a sufficient distance 22708. frequency reuse handoff clustering radio survey 22709. 22710. A connection is momentarily broken during the cell-to-cell transfer is called ______. 22711. hard handoff soft handoff medium handoff light handoff 22712. 22713. Transmission from mobile stations to the base stations is called 22714. forward link reverse link control link user link 22715. 22716. It is a database in the PCS network that stores information about the user, including home subscription information and what supplementary services the user is subscribed to. 22717. visitor location register home location register equipment identification register authentication register 22718. 22719. Determine the transmit power for a CDMA mobile unit that is receiving a signal from the base station at 100 dBm 22720. 12 dBm 24 dBm 36 dBm 14 dBm 22721. 22722. When transmitting digital information, voice transmission is inhibited, this is called ______. 22723. quieting muting blank-and-burst any of these 22724. 22725. A metropolitan area of 1000 square km is to be covered by cells with a radius of 2 km. How many cell sites would be required, assuming hexagonal cells? 22726. 72 73 74 75 22727. 22728. Refers to a land station in a maritime mobile services 22729. coast station maritime station coast earth station ship earth station 22730. 22731. Class of orthogonal spreading coded used in CDMA communication. 22732. Color code Walsh code PCS code CDMA 22733. 22734. In a spread spectrum system, the tendency for a stronger signals to interfere with the reception of weaker signals. 22735. near-far field near-far effect direct-sequence spread-spectrum 22736. 22737. Macrocells have base stations transmit power between _____. 22738. 3W to 7W 1W to 6W 2W to 8W 0.1W to 5W 22739. 22740. It is when the area of a cell, or independent component coverage areas of a cellular system, is further divided, thus creating more cell areas. 22741. cell splitting cell clustering cell partitioning cell sectoring 22742. 22743. It is when a mobile unit moves from one cell to another from one company's service area to another company's service area. 22744. roaming handoff handover paging 22745. 22746. It is a 34-bit binary code that represents the 10-digit telephone number 22747. electronic serial number system identification digital color code mobile identification number 22748. 22749. The bandwidth of WCDMA is __ times larger than CDMAone. 22750. 4 5 6 7 22751. 22752. Receive channel 22 is 870.66 MHz. Receive channel 23 is 22753. 870.36 MHz 870.63 MHz 870.96 MHz 870.69 MHz 22754. 22755. In mobile wireless communication, the radio equipment and the propagation path 22756. FSL air interface direct link mobile interface 22757. 22758. The signaling fone may be transmitted on the voice channel during a call in what frequency? 22759. 25 kHz 20 kHz 15 kHz 10 kHz 22760. 22761. Station in the mobile service not intended to be used while in motion. 22762. base station fixed station coast station land station 22763. 22764. In the GSM system, a "smart card" containing all user information, which is inserted into the phone before use. 22765. IMSI IMEI IMTS SIM 22766. 22767. Determine the number of channels per cluster of a cellular telephone area comprised of 10 clusters with seven cells in each cluster and 10 channels in each cell. 22768. 70 channels per cluster 700 channels per cluster 7000 channels per cluster 7 channels per cluster 22769. 22770. Determine the channel capacity if 7 macrocells with 10 channels per cell is split into 4 minicells 22771. 120 channels per area 360 channels per area 280 channels per area 460 channels per area 22772. 22773. Technique of spread spectrum that breaks message into fixed-size blocks of data with each block transmitted in sequence except on the different carrier frequency. 22774. spread spectrum time-division multiplexing frequency-hopping direct sequence 22775. 22776. A base and mobile is separated by 5 km. What is the propagation time for a signal traveling between them? 22777. 14.5 usec 18.9 usec 20.8 usec 16.7 usec 22778. 22779. A digital identification associated with a cellular system 22780. MIN ESN SAT SIM 22781. 22782. A new regulation issued by the National Telecommunications Commission providing for the guideline for mobile personal communication having a global coverage using satellite. 22783. NMT GMPCS GSM TACS 22784. 22785. The following are the typical cluster size except 22786. 3 7 12 15 22787. 22788. Provides a centralized administration and maintenance point for the entire network end interfaces with the public telephone network through the telephone wireline voice trunks and data links 22789. PSTN MTSO central offices MSC 22790. 22791. It is a digital telephone exchange located in the MTSO that is the heart of a telephone system 22792. mobile switching center electronic switching center gateway switching center electronic mobile switching center 22793. 22794. A database in the PCS network that stores information pertaining to the identification and type of equipment that exist in the mobile unit. 22795. visitor location register home location register equipment identification register authentication register 22796. 22797. When a signal from a mobile cellular unit drops below a certain level, what action occurs? 22798. The unit is "handed off" to a closer cell. The call is terminated. The MTSO increases power level. The cell site switches antenna. 22799. 22800. A method of transmitting data on AMPS cellular telephone voice channels that are temporary unused. 22801. cellular digital packet data digital color code control mobile attenuation code electronic serial code 22802. 22803. A vehicle travels through a cellular system at 100 km per hour. Approximately how often will handoffs occur if the cell radius is 10 km. 22804. 12 min 14 min 16 min 18 min 22805. 22806. In the GSM system, a telephone number that is unique to a given user, worldwide. 22807. IMTS IMEI IMSI SIM 22808. 22809. An area divided into hexagonal shapes that fit together to form a honeycomb pattern is called ______. 22810. cluster transport area cell area of responsibility 22811. 22812. Determine the channel capacity of a cellular telephone area comprised of twelve macrocell with ten channels per cell 22813. 12 channels per area 120 channels per area 1200 channels per area 12000 channels per area 22814. 22815. Transmission from base stations to mobile stations is called ____. 22816. forward link reverse link control link user link 22817. 22818. The output power of a cellular radio is controlled by the 22819. user or caller cell site called party MTSO 22820. 22821. EDGE channel size is about 22822. 250 kHz 200 kHz 150 kHz 100 kHz 22823. 22824. A switching facility connecting cellular telephone base stations to each other and to the public switched telephone network. 22825. MTSO MSC VLR AuC 22826. 22827. A radio land station in the land mobile service 22828. land station ship earth station base station mobile station 22829. 22830. Transmission of brief text messages, such as pages or e-mail, by cellular radio or PCS. 22831. SMS MMS paging raking 22832. 22833. The point when the cell reaches maximum capacity occurs when the number of subscribers wishing to place a call at any given time equals the number of channels in the cell 22834. saturation blocking traffic maximum traffic load any of these 22835. 22836. In IS-41 standard, it is a process where the mobile unit notifies a serving MTSO of its presence and location through a base station controller. 22837. dependent registration autonomous registration air interface BTS to BSC interface 22838. 22839. Cellular telephones use which operation? 22840. simplex half-duplex full-duplex triplex 22841. 22842. A receiver capable of receiving several versions of the same signal with different arrival times and combining the received versions into a single signal with better quality 22843. scanners rake receivers mobile subscriber unit mobile stations 22844. 22845. In CMTS, the most important database for GSM is ____. 22846. VLR HLR BTS AUC 22847. 22848. In CMTS, the number of duplex voice channels for AMPS is ____. 22849. 676 285 395 790 22850. 22851. A geographic cellular radio coverage area containing three of more group of cells 22852. cluster cell radio channel MSC/VLR area 22853. 22854. A flawless cell-to-cell transfer is called ____. 22855. hard handoff soft handoff heavy handoff light handoff 22856. 22857. The bit length of System Identification (SID) 22858. 32 15 10 8 22859. 22860. The RF power output of a transmitter in a cellular mobile telephone system authorized by NTC for use in the Philippines. 22861. 20.5 dBm 31.5 dBm 34.8 dBm 22.1 dBm 22862. 22863. A class III mobile phone using AMPS has an ERP of 22864. 4 W 1.6 W 600 mW 1.4 W 22865. 22866. ____ is measuring the propagated field strength over the projected service area. 22867. radio monitoring radio sounding radio survey none of these 22868. 22869. Transmission of data in two directions on a channel by using different time slots for each directions. 22870. time-division multiplexing time-division multiple access time-division duplexing time-division 22871. 22872. When the cluster size is reduced with a constant cell size, what happens to the total channel capacity? 22873. decreases increases stays constant depends on the number of cell cites 22874. 22875. The transfer of a mobile unit from one base station's control to another base station's control 22876. handoff paging roaming dualization 22877. 22878. What is the frequency deviation of AMPS? 22879. 12 kHz 6 kHz 3 kHz 18 kHz 22880. 22881. The bit length of Digital Color Code (DCC) 22882. 2 3 4 5 22883. 22884. A transmit channel has a frequency of 837.6 MHz. The receive channel frequency is 22885. 729.6 MHz 837.6 MHz 867.6 MHz 882.6 MHz 22886. 22887. A frequency-hopping spread-spectrum system hops to each of 100 frequencies every 10 seconds. How long does it spread on each frequency? 22888. 0.2 sec/hop 0.4 sec/hop 0.3 sec/hop 0.1 sec/hop 22889. 22890. What is the transmission rate of a GSM cellular system? 22891. 128 kbps 240 kbps 64 kbps 270 kbps 22892. 22893. A card with an embedded integrated circuit that can be used for functions such as storing subscriber information for a PCS system. 22894. smart card SIM Intelligent card Credit card 22895. 22896. It is a means of avoiding full-cell splitting where the entire area would otherwise need to be segmented into smaller cells. 22897. segmentations dualization sectoring splitting 22898. 22899. A channel used for transferring control and diagnostic information between mobile users and a central cellular telephone switch through the base stations. 22900. forward channel voice channel control channel reverse channel 22901. 22902. It is the provision of voice communication using internet protocol technology, instead of traditional circuit switched technology. 22903. WAP GPRS VOIP WIFI 22904. 22905. Determine the total number of channel capacity of a cellular telephone area comprised of 10 clusters with seven cells in each cluster and 10 channels in each cell. 22906. 7 channels 70 channels 700 channels 7000 channels 22907. 22908. Technique used in spread spectrum that adds a high-bit rate pseudorandom code to a low bit rate information signal to generate a high-bit rate pseudorandom signal closely resembling noise that contains both the original data signal and pseudorandom noise. 22909. direct-sequence frequency-division multiplexing frequency hopping CDMA 22910. 22911. Refers to the first generation of local loop system in telecommunication technology 22912. TACS DECT Analog cellular GSM 22913. 22914. An information sent by the base station in a cellular radio system set the power level of the mobile transmitter. 22915. cellular digital packet data digital color code control mobile attenuation code electronic serial code 22916. 22917. A 32-bit binary code permanently assigned to each of the mobile unit 22918. supervisory audio tone station class mark electronic serial number visitor location register 22919. 22920. It serves as central control for all users within that cell 22921. base stations antennas transceivers mobile subscriber units 22922. 22923. What modulation technique is used by Advanced Mobile Phone System (AMPS) 22924. WBFM VSB NBFM FSK 22925. 22926. A database in the PCS network that stores information about subscribers in a particular MTSO serving area 22927. international mobile subscriber identification visitor location register home location register authentication register 22928. 22929. In cellular phone, a memory location that stores the telephone number(s) to be used on the system. 22930. EPROM UVPROM EEPROM NAM 22931. 22932. A province in the Philippines has an area 2000 sq. kms. It has to be covered by a cellular mobile telephone service using cells with a radius of 3 kms. Assuming hexagonal cells, find the number of cell sites needed. 22933. 100 500 166 145 22934. 22935. The modulation technique used by GSM cellular system. 22936. QAM Phase Shift Keying Gaussian Minimum Shift Keying Frequency Shift Keying 22937. 22938. Microcells have base stations transmit power between ____. 22939. 0.4W to 0.7W 1W to 6W 0.5W to 8W 0.1W to 1W 22940. 22941. Determine the receive carrier frequencies for AMPS channel 3 and channel 991 22942. 870.09 MHz and 869.04 MHz 879.09 MHz and 859.04 MHz 869.09 MHz and 870.04 MHz 869.04 MHz and 870.09 MHz 22943. 22944. Decreasing co-channel interference while increasing capacity by using directional antenna is called ____. 22945. clustering splitting partitioning sectoring 22946. 22947. Soft handoff normally takes ____ of time delay. 22948. 400 ms 300 ms 200 ms 100 ms 22949. 22950. Component of a cellular telephone network that manages each of the radio channels at each site. 22951. base station controllers base transceiver stations mobile switching center mobile telephone switching center 22952. 22953. The bit length of Station Class Mark (SCM). 22954. 4 5 8 10 22955. 22956. The master control center for a cellular telephone system is the 22957. Cell site MTSO Central office Branch office 22958. 22959. The maximum frequency deviation of an FM cellular transmitter is 22960. 6 kHz 12 kHz 30 kHz 45 kHz 22961. 22962. A receiver channel has a frequency is 872.4 MHz. to develop an 82.2 MHz IF, the frequency synthesizer must apply an local oscillator signal of ____ (The local oscillator is usually higher than the receive frequency) 22963. 790.2 MHz 827.4 MHz 954.6 MHz 967.4 MHz 22964. 22965. A class I mobile phone using AMPS has an ERP of 22966. 6 dBW 2 dBW -2 dBW -6 dBW 22967. 22968. A mobile telephone service using trunked channels but not cellular nature 22969. IMTS MTSO IMSI IMEI 22970. 22971. The GSM cellular radio system uses GMSK in a 200-kHz, with a channel data rate of 270.833 kbps. Calculate the frequency shift between mark and space in kHz? 22972. 135.4165 153.6514 315.4651 513.1654 22973. 22974. A cellular system is capable of coping with a handoffs once every 2 minutes. What is the maximum cell radius if the system must be capable of working with cars traveling at highway speed of 120 km/hr? 22975. 3 km 1 km 4 km 6 km 22976. 22977. Radio communication operation service between mobile and land stations or between mobile stations. 22978. land mobile land mobile satellite service mobile service maritime mobile service 22979. 22980. A multiple access technique used in GSM cellular system. 22981. FDMA CDMA TDMA TACS 22982. 22983. This is the Nordic analog mobile radio telephone system originally used in Scandinavia 22984. NMT GSM PCN PCS 22985. 22986. The combination of the mobile cellular phone and the cell-site radio equipment is known as 22987. forward link base transceiver station air interface base station controller 22988. 22989. The duplex frequency of GSM 22990. 40 MHz 80 MHz 120 MHz 30 MHz 22991. 22992. The channel separation of GSM channel 22993. 270 kHz 200 kHz 120 kHz 60 kHz 22994. 22995. The number of control channels for AMPS 22996. 25 23 21 19 22997. 22998. The modulation technique used audio signal for TACS 22999. FM FSK TFSK QAM 23000. 23001. Speech coding rate for GSM 23002. 80 kbps 25 kbps 21 kbps 13 kbps 23003. 23004. Number of channels for GSM 23005. 333 666 124 248 23006. 23007. It is a database that contains information about the identity of mobile equipment that prevents calls from stolen, unauthorized, or defective mobile stations. 23008. Equipment Identity Register Authentication Center Home Location Register Visitor Location Register 23009. 23010. It provides all the control functions and physical links between the MSC and BTS 23011. OSS OMC MSC BSC 23012. 23013. It is the functional entity from which the operator monitors and controls the mobile communication system. 23014. Operation and Maintenance System Mobile Switching Center Gateway Mobile Switching Center Operation and Support System 23015. 23016. A node in the switching system of GSM that provides integrated voice, fax and data messaging. 23017. Gateway Mobile Switching Center Mobile Service Node GSM Internetworking Unit Message Center 23018. 23019. It is a node in the switching system of GSM that handles mobile intelligent network services. 23020. Message Center Gateway Mobile Switching Center Mobile Service Unit Mobile Switching Center 23021. 23022. The modulation scheme used for NADC 23023. NFSK Quarterwavelength Shifted QPSK GFSK Trellis coding 23024. 23025. 23026. 23027. 23028. 23029. 23030. 23031. 23032. 23033. MULTIPLE CHOICE QUESTIONS IN 23034. SATELLITE COMMUNICATIONS 23035. Electronics Systems and Technologies 23036. By 23037. Melvin C. Arceo 23038. 23039. 23040. 23041. 23042. 23043. 23044. 23045. 23046. 23047. ENCODED BY: 23048. LAQUI, Louise Ruelyn J. 23049. It is a celestial body that orbits around a planet. 23050. 23051. Primary body 23052. Satellite 23053. Heavenly bodies 23054. Quasars 23055. 23056. It is a position and timing service that is available to all GPS users on a continuous, worldwide basis with no direct charge. 23057. 23058. PPI 23059. PPS 23060. SPS 23061. SSP 23062. 23063. The geometric shape of a non-circular orbit of a satellite is ____. 23064. 23065. Ellipse 23066. Parabolic 23067. Hyperbolic 23068. Paraboloid 23069. 23070. The circuit that provides channelization in a transponder is the 23071. 23072. Mixer 23073. Local oscillator 23074. Bandpass filter 23075. HPA 23076. 23077. The three axes referred to the three-axis attitude stabilization are; except 23078. 23079. Pitch 23080. Yaw 23081. Roll 23082. Speed 23083. 23084. A ground station is operating to a geostationary satellite at a 5 degrees angle of elevation. Calculate the round-trip time between ground station to satellites in a geostationary orbit. 23085. 23086. 456.45 ms 23087. 275.58 ms 23088. 137.79 ms 23089. 126.89 ms 23090. 23091. The escape velocity of the earth is approximately 23092. 23093. 30,000 km/hr 23094. 25,000 mi/hr 23095. 35,000 m/s 23096. 25,000 km/hr 23097. 23098. A satellite radio repeater is called ____. 23099. 23100. Repeater 23101. Transponder 23102. Satellite 23103. Mixer 23104. 23105. Calculate the angle of declination for an antenna using a polar mount at a latitude of 45 degrees. 23106. 23107. 3.2 degrees 23108. 1.3 degrees 23109. 4.2 degrees 23110. 6.81 degrees 23111. 23112. The time transfer accuracy used with reference to the Universal Transmitter Mercator Grid is ____. 23113. 23114. UTC 23115. UTMG 23116. GMT 23117. UTM 23118. 23119. It is caused by the inertia of the satellite balanced by the earth’s gravitational pull. 23120. 23121. Centrifugal force 23122. Centripetal force 23123. Speed 23124. Earth’s rotation 23125. 23126. In satellites, it includes control mechanism that support the payload operation. 23127. 23128. Bus 23129. Payload 23130. Ground segment 23131. Space segment 23132. 23133. A satellite transmitter operates at a 4 GHz with a transmitter power of 7W and an antenna gain of 40 dBi. The receiver has antenna gain of 30 dBi, and the path length is 40,000 km. calculate the signal strength at the receiver. 23134. 23135. -88 dBm 23136. -98 dBm 23137. -77 dBm 23138. -79.8 dBm 23139. 23140. The satellite subsystem that monitors and controls the satellite is the 23141. 23142. Propulsion system 23143. Power subsystem 23144. Communications subsystem 23145. Telemetry, tracking, and command subsystems 23146. 23147. Standard positioning service has time transfer accuracy to Universal Transfer Mercator Grid within ____. 23148. 23149. 140 nanoseconds 23150. 340 nanoseconds 23151. 230 nanoseconds 23152. 530 nanoseconds 23153. 23154. A satellite remains in orbit because the centrifugal force caused by its rotation around the Earth is counterbalanced by Earth’s ____. 23155. 23156. Centripetal force 23157. Inertia 23158. Gravitational pull 23159. Speed 23160. 23161. A TVRO installation for use with C-band satellite (download frequency at 4 GHz), has a diameter of about 3.5 meters and an efficiency of 60%. Calculate the gain. 23162. 23163. 41 dB 23164. 19 dB 23165. 29 dB 23166. 9 dB 23167. 23168. Which of the following is not a typical output from the GPS receiver? 23169. 23170. Latitude 23171. Speed 23172. Altitude 23173. Longitude 23174. 23175. The law that states that a satellite will orbit a primary body following an elliptical path. 23176. 23177. 1st law of Kepler 23178. 2nd law of Kepler 23179. 3rd law of Kepler 23180. 4th law of Kepler 23181. 23182. Telephone communication takes place between two earth stations via a satellite that is 40,000 km from each station. Suppose Bill, at station 1, asks a question and Sharon, at station 2, answers immediately, as soon as she hears the question. How much time elapses between the end of Bill’s question and the beginning of Sharon’s reply, as heard by Bill? 23183. 23184. 0.26 sec 23185. 3.2 sec 23186. 0.52 sec 23187. 1.6 sec 23188. 23189. In GPS, it is accomplished by manipulating navigation message orbit data (epsilon) and/or the satellite clock frequency (dither). 23190. 23191. Selective availability 23192. Reverse error notification 23193. Forward error notification 23194. Two dimensional reporting 23195. 23196. The modulation normally used with digital data is 23197. 23198. AM 23199. FM 23200. SSB 23201. QPSK 23202. 23203. Kepler’s 2nd law is known as 23204. 23205. Law of gravity 23206. Law of areas 23207. Newton’s law of motion 23208. Harmonic law 23209. 23210. A receiving antenna with a gain of 40 dB looks at a sky with a noise temperature of 15 K. the loss between the antenna and the LNA input, due to the feedhorn is 0.4 dB, and the LNA has a noise temperature of 40K. Calculate the G/T? 23211. 23212. 13.4 dB 23213. 39 dB 23214. 20.6 dB 23215. 11.2 dB 23216. 23217. The operational satellites of Navstar GPS are revolving around Earth in ____ orbital planes. 23218. 23219. 4 23220. 3 23221. 5 23222. 6 23223. 23224. Kepler’s 3rd law is also known as 23225. 23226. Law of gravity 23227. Law of areas 23228. Newton’s law of motion 23229. Harmonic law 23230. 23231. The basic technique used to stabilize a satellite is 23232. 23233. Gravity-forward motion balance 23234. Spin 23235. Thruster control 23236. Solar panel orientation 23237. 23238. Calculate the length of the path to a geostationary satellite from an earth station where the angle of elevation is 30 degrees. 23239. 23240. 55 x 10^3 km 23241. 13 x 10^3 km 23242. 23 x 10^3 km 23243. 39 x 10^3 km 23244. 23245. Navstar GPS is a ____. 23246. 23247. LEO 23248. MEO 23249. HEO 23250. GEO 23251. 23252. The satellite is orbiting in the same direction as the Earth’s rotation and at angular velocity greater than that of the Earth. 23253. 23254. Retrograde 23255. Synchronous 23256. Posigrade 23257. Asynchronous 23258. 23259. Find the orbital period of the satellite in a circular orbit 500 km above the Earth’s surface 23260. 23261. 1.6 hrs 23262. 3.2 hrs 23263. 2.4 hrs 23264. 6.4 hrs 23265. 23266. Satellite orbiting in the opposite direction as the Earth’s rotation and at angular velocity less than that of the Earth 23267. 23268. Asynchronous 23269. Synchronous 23270. Posigrade 23271. Retrograde 23272. 23273. A transponder that demodulates the baseband signals and then demodulates a carrier is known as ____ transponder. 23274. 23275. Single-conversion 23276. Double-conversion 23277. Regenerative 23278. Degenerative 23279. 23280. Low Earth Orbit (LEO) satellite orbits around the earth at a height of approximately ____. 23281. 23282. 3000 miles 23283. 1000 miles 23284. 575 miles 23285. 370 miles 23286. 23287. Power amplification in a transponder is usually provided by 23288. 23289. klystron 23290. TWT 23291. Transistor 23292. Magnetron 23293. 23294. Which of the following clocks is developed for Galileo satellite? 23295. 23296. Cesium Atomic Frequency Standard 23297. Rubidium Atomic Frequency Standard 23298. Ruby Atomic Frequency Standard 23299. Hydrogen Frequency Standard 23300. 23301. Master control station of GPS is located in ____. 23302. 23303. Colorado 23304. California 23305. Alaska 23306. New York 23307. 23308. Medium Earth Orbit (MEO) satellite orbits around the earth at a height approximately ____. 23309. 23310. 3,000 miles to 6,000 miles 23311. 4,000 miles to 8,000 miles 23312. 6,000 miles to 12,000 miles 23313. 8,000 miles to 10,000 miles 23314. 23315. A satellite stays in orbit because the following two factors are balanced 23316. 23317. Satellite weight and speed 23318. Gravitational pull and inertia 23319. Centripetal force and speed 23320. Satellite weight and the pull of the moon and sun 23321. 23322. A ____ circuit in the transponder performs the frequency conversion. 23323. 23324. HPA 23325. Mixer 23326. Local oscillator 23327. LPA 23328. 23329. Geosynchronous satellites are high-altitude earth-orbit satellites with heights about ____. 23330. 23331. 22,300 miles 23332. 21,000 miles 23333. 8,000 miles 23334. 10,400 miles 23335. 23336. The input circuit to a transponder is the ____. 23337. 23338. BPF 23339. HPA 23340. LPA 23341. Any of these 23342. 23343. The access scheme used by GPS 23344. 23345. FDMA 23346. OFDMA 23347. TDMA 23348. CDMA 23349. 23350. The point in an orbit which is located farthest from earth 23351. 23352. Perigee 23353. Apogee 23354. Line of apsides 23355. Point of shoot 23356. 23357. Using very narrow beamwidth antennas to isolate signals on the same frequency is known as ____. 23358. 23359. Spatial isolation 23360. Footprint 23361. Frequency reuse 23362. Boresight 23363. 23364. The point in an orbit which is located closest to Earth 23365. 23366. Point of shoot 23367. Apogee 23368. Line of apsides 23369. Perigee 23370. 23371. The most popular satellite frequency range is 4 to 6 GHz and is called the ____ band. 23372. 23373. C 23374. L 23375. Ka 23376. Ku 23377. 23378. All satellites rotate around the earth in an orbit that forms a plane that passes through the center of gravity of earth called ____. 23379. 23380. Focus 23381. Geocenter 23382. Orbit 23383. Center 23384. 23385. In satellite communications, the type of modulation used in voice and video signals is 23386. 23387. AM 23388. FM 23389. SSB 23390. QPSK 23391. 23392. In satellite communications, type of orbit which is virtually all orbits except those travel directly above the equator or directly over the North or the South poles. 23393. 23394. Equatorial orbit 23395. Polar orbit 23396. Geosynchronous orbit 23397. Inclined orbit 23398. 23399. A common up-converter and down-converter IF insatelite communications is 23400. 23401. 36 MHz 23402. 40 MHz 23403. 70 MHz 23404. 500 MHz 23405. 23406. It is the angle between the earth’s equatorial plane and the orbital plane of the satellite measured counterclockwise. 23407. 23408. Angle of elevation 23409. Angle of azimuth 23410. Angle of inclination 23411. Angle of tetrahedron 23412. 23413. Which of the following types of HPA is not used in earth stations? 23414. 23415. TWT 23416. Klystron 23417. Transistors 23418. Magnetron 23419. 23420. Galileo satellite’s mass is ____. 23421. 23422. 880 kg 23423. 675 kg 23424. 900 kg 23425. 540 kg 23426. 23427. The point where a polar or inclined orbit crosses the equatorial plane traveling from north to south 23428. 23429. Ascending node 23430. Line of nodes 23431. Descending node 23432. Diagonal nodes 23433. 23434. The receive GCE system in an earth station performs what function/s 23435. 23436. Modulation and multiplexing 23437. Up conversion 23438. Demodulation and demultiplexing 23439. Down conversion 23440. 23441. The term generally associated with the table showing the position of a heavenly body on the number of dates in a regular sequence. 23442. 23443. Astronomical almanac 23444. Smith 23445. Ephemeris 23446. Space reporting 23447. 23448. The point where a polar or inclined orbit crosses the equatorial plane traveling from south to north. 23449. 23450. Ascending node 23451. Descending node 23452. Diagonal node 23453. Inclined node 23454. 23455. The line joining the ascending and descending node is called ____. 23456. 23457. Line of apsides 23458. Line of nodes 23459. Line of shoot 23460. Any of these 23461. 23462. When the satellite rotates in an orbit directly above the equator, usually in circular pattern. This type of orbit is called ____. 23463. 23464. Polar orbit 23465. Synchronous orbit 23466. Geosynchronous satellite 23467. Equatorial orbit 23468. 23469. The Navstar GPS satellite system was declared fully operational as of ____. 23470. 23471. April 17, 1995 23472. April 24, 1995 23473. April 27, 1995 23474. April 10, 1995 23475. 23476. The HPAs in most satellites are 23477. 23478. TWTs 23479. Vacuum tubes 23480. Klystrons 23481. Magnetrons 23482. 23483. The physical location of a satellite is determined by its 23484. 23485. Distance from the earth 23486. Latitude and longitude 23487. Reference to the stars 23488. Position relative to the sun 23489. 23490. When the satellite rotates in a path that takes it over the north and south poles in an orbit perpendicular to the equatorial plane. This type of orbit is called ____. 23491. 23492. Inclined orbit 23493. Polar orbit 23494. Geosynchronous orbit 23495. Diagonal orbit 23496. 23497. The azimuth angles and the angle of elevation is collectively known as ____. 23498. 23499. Antennas look angles 23500. Antennas see angles 23501. Antennas keep angles 23502. Antennas satellite angles 23503. 23504. The point on the surface of the Earth directly below the satellite. 23505. 23506. Satellite point 23507. Latitude 23508. Longitude 23509. Subsatellite point 23510. 23511. It is the vertical angle formed between the direction of travel of an electromagnetic wave radiated from an earth station antenna pointing directly toward a satellite and the horizontal plane. 23512. 23513. Angle of depression 23514. Angle of inclination 23515. Angle of elevation 23516. Angle of azimuth 23517. 23518. The unique number used to encrypt the signal from that of the GPS satellite. 23519. 23520. SV 23521. UV 23522. PRN 23523. ESN 23524. 23525. The minimum acceptable angle of elevation 23526. 23527. 6 degrees 23528. 4 degrees 23529. 5 degrees 23530. 7 degrees 23531. 23532. It is the horizontal angular distance from a reference direction either the southern or northern most point of the horizon. 23533. 23534. Angle of elevation 23535. Latitude 23536. Longitude 23537. Azimuth 23538. 23539. It is defined as the horizontal pointing angle of an earth station antenna. 23540. 23541. Angle of inclination 23542. Azimuth angle 23543. Latitude 23544. Longitude 23545. 23546. Determines the farthest satellite away that can be seen looking east or west of the earth station’s longitude 23547. 23548. Radio horizon 23549. Optical horizon 23550. Terrestrial limits 23551. Limits of visibility 23552. 23553. The spatial separation of a satellite is between ____. 23554. 23555. 3 to 6 degrees 23556. 1 to 2 degrees 23557. 5 to 8 degrees 23558. 8 to 16 degrees 23559. 23560. The geographical representation of a satellite antenna’s radiation pattern is called a ____. 23561. 23562. Field intensity 23563. Footprint 23564. Radiation propagation 23565. Polarization 23566. 23567. The GPS satellite identification which is assigned according to the order of the vehicle’s launch. 23568. 23569. SV 23570. EV 23571. PRN 23572. ESN 23573. 23574. The smallest beam of a satellite that concentrates their power to very small geographical areas. 23575. 23576. Hemispherical beam 23577. Global beam 23578. Spot beam 23579. Any of these 23580. 23581. Satellite’s radiation pattern that typically target up to 20% of the Earth’s surface. 23582. 23583. Hemispherical beam 23584. Global beam 23585. Spot beam 23586. Any of these 23587. 23588. The key electronic component in a communications satellite is the 23589. 23590. Telemetry 23591. Command and Control system 23592. On-board computer 23593. Transponder 23594. 23595. The radiation pattern that has a satellite’s antenna beamwidth of 17 degrees and are capable of covering approximately 42% of the earth’s surface. 23596. 23597. Hemispherical beam 23598. Earth beam 23599. Spot beam 23600. Any of these 23601. 23602. The first active satellite 23603. 23604. Moon 23605. Sputnik I 23606. Score 23607. Echo 23608. 23609. Sputnik I transmitted telemetry information for 23610. 23611. 1 week 23612. 21 days 23613. 15 days 23614. 30 days 23615. 23616. The US counterpart of Sputnik I 23617. 23618. Syncom 23619. Telstar 23620. Echo 23621. Explorer I 23622. 23623. Explorer I lasted for ____. 23624. 23625. 5 months 23626. 6 months 23627. 12 months 23628. 2 months 23629. 23630. Navstar GPS satellite grouping that can operate continuously for 180 days between uploads from the ground. 23631. 23632. Block III 23633. Block IIa 23634. Block II 23635. Block IIR 23636. 23637. It was the first artificial satellite used for relaying terrestrial communications 23638. 23639. Score 23640. Explorer I 23641. Sputnik I 23642. Syncom I 23643. 23644. Which of the following satellite rebroadcast President Eisenhower’s 1958 Christmas message? 23645. 23646. Telstar I 23647. Telstar II 23648. Echo 23649. Score 23650. 23651. The satellite or space segment of Navstar GPS is consist of ____ operational satellites. 23652. 23653. 30 23654. 24 23655. 14 23656. 20 23657. 23658. It was the first satellite to accomplish transatlantic transmission. 23659. 23660. Courier 23661. Echo 23662. Telstar 23663. Syncom 23664. 23665. It is the first transponder-type satellite 23666. 23667. Telstar I 23668. Sputnik I 23669. Syncom 23670. Courier 23671. 23672. The first active satellite to simultaneously receive and transmit radio signals. 23673. 23674. Telstar I 23675. Telstar II 23676. Intelsat 23677. Syncom 23678. 23679. The satellite communications channel in a transponder are defined by the 23680. 23681. LNA 23682. Bandpass filter 23683. Mixer 23684. Input signals 23685. 23686. The satellite that was damaged by radiation from a newly discovered Van Allen Belts and consequently lasted for two weeks. 23687. 23688. Telstar I 23689. Telstar II 23690. Intelsat 23691. Syncom 23692. 23693. As the height of a satellite orbit gets lower, the speed of the satellite 23694. 23695. Increases 23696. Decreases 23697. Remains the same 23698. None of the above 23699. 23700. The satellite that was lost in space in its first attempt to place it in a geosynchronous orbit. 23701. 23702. Syncom I 23703. Telstar I 23704. Telstar II 23705. Courier 23706. 23707. Intelsat I which was the first commercial telecommunications satellite is called ____. 23708. 23709. Domsat 23710. Molniya 23711. Early bird 23712. Courier 23713. 23714. Block II Navstar GPS satellites can operate for approximately ____ between the receiving updates and corrections from the control segment of the system. 23715. 23716. 5.5 days 23717. 3.5 days 23718. 6 days 23719. 7 days 23720. 23721. The angle of inclination of a satellite in polar orbit is nearly ____. 23722. 23723. 45 degrees 23724. 90 degrees 23725. 30 degrees 23726. 60 degrees 23727. 23728. It is the time it takes earth to rotate back to the same constellation 23729. 23730. Revolution 23731. Rotation 23732. Sidereal period 23733. Year 23734. 23735. Satellites with orbital pattern like Molniya are sometimes classified as 23736. 23737. LEO 23738. MEO 23739. GEO 23740. HEO 23741. 23742. The process of maneuvering a satellite within a preassigned window is called 23743. 23744. Satellite keeping 23745. Station controlling 23746. Station keeping 23747. Satellite controlling 23748. 23749. Navstar GPS satellite grouping capacble of detecting certain error conditions, then automatically transmitting a coded message indicating that it is out of service. 23750. 23751. Block I 23752. Block IIa 23753. Block II 23754. Block IIR 23755. 23756. Galileo Satellites has a lifespan of ____. 23757. 23758. > 12 years 23759. > 15 years 23760. > 20 years 23761. > 25 years 23762. 23763. The height of a satellite in a synchronous equatorial orbit is 23764. 23765. 100 mi 23766. 6800 mi 23767. 22,300 mi 23768. 35,860 mi 23769. 23770. An orbit that is 36,000 km away from the geocenter of the earth is called 23771. 23772. Geosynchronous orbit 23773. Clarke orbit 23774. Clarke belt 23775. Any of these 23776. 23777. The main function of a communications satellite is as 23778. 23779. Repeater 23780. Reflector 23781. Beacon 23782. Observation platform 23783. 23784. Navstar GPS grouping intended to be used only for self testing. 23785. 23786. Block I 23787. Block III 23788. Block II 23789. Block IIR 23790. 23791. It is the direction of maximum gain of the earth station antenna 23792. 23793. Footprint 23794. Boresight 23795. Angle of elevation 23796. Angle of azimuth 23797. 23798. A circular orbit around the equator with 24-h period is called 23799. 23800. Elliptical orbit 23801. Geostationary orbit 23802. Polar orbit 23803. Transfer orbit 23804. 23805. A classification of satellite that uses the angular momentum of its spinning body to provide roll and yaw stabilization. 23806. 23807. Roll stabilizer satellite 23808. Yaw stabilizer satellite 23809. Spinner stabilizer satellite 23810. Three-axis stabilizer satellite 23811. 23812. Most satellites operate in which frequency band? 23813. 23814. 30 to 300 MHz 23815. 300 MHz to 3 GHz 23816. 3 to 30 GHz 23817. Above 300 GHz 23818. 23819. The method of assigning adjacent channels different electromagnetic polarization is called 23820. 23821. Frequency reuse 23822. Polarization 23823. Multi-accessing 23824. Interference 23825. 23826. It implies that more than one user has an access to one or more radio channels 23827. 23828. Co-channel interference 23829. Satellite multi-accessing 23830. Frequency reuse 23831. Diversity 23832. 23833. The main power sources for a satellite are 23834. 23835. Batteries 23836. Solar cells 23837. Fuel cells 23838. Thermoelectric generators 23839. 23840. A type of satellite’s multiple-accessing method that allows all users continuous and equal access of the entire transponder bandwidth by assigning carrier frequencies on a temporary basis using statistical assignment process. 23841. 23842. TDMA 23843. FDMA 23844. DAMA 23845. CDMA 23846. 23847. Batteries are used to power all satellite subsystems 23848. 23849. All the time 23850. Only during emergencies 23851. During eclipse periods 23852. To give the solar arrays a rest 23853. 23854. The highly accurate timing clocks onboard the GPS satellite. 23855. 23856. Plutonium clocks 23857. Cesium atomic clocks 23858. Hydrogen clocks 23859. Fossil clocks 23860. 23861. It is defined as the art or science of plotting, ascertaining, or directing the course of movement. 23862. 23863. Ranging 23864. Detection 23865. Navigation 23866. Driving 23867. 23868. Galileo satellite system is positioned in ____. 23869. 23870. 5 circular orbits 23871. 3 circular orbits 23872. 2 circular orbits 23873. 6 circular orbits 23874. 23875. The maximum height of an elliptical orbit is called the 23876. 23877. Perigee 23878. Apex 23879. Zenith 23880. Apogee 23881. 23882. The most ancient and rudimentary method of navigation is ____. 23883. 23884. Wandering 23885. Celestial navigation 23886. Piloting 23887. Radio navigation 23888. 23889. The jet thrusters are usually fired to 23890. 23891. Main attitude 23892. Put the satellite into transfer orbit 23893. Inject the satellite into the geosynchronous orbit 23894. Bring the satellite back to earth 23895. 23896. A method of navigation where direction and distance are determined from precisely timed sightings of celestial bodies, including the stars and the moon. 23897. 23898. Electronic navigation 23899. Heavenly navigation 23900. Radio navigation 23901. Celestial navigation 23902. 23903. Navstar satellite takes approximately ____ hours to orbit Earth. 23904. 23905. 20 23906. 6 23907. 12 23908. 18 23909. 23910. A method of navigation where it fixes a position or direction with respect to familiar, significant landmarks such as railroad tracks, water towers, barns, mountain peaks and bodies or water. 23911. 23912. Dead reckoning 23913. Radio navigation 23914. Wandering 23915. Piloting 23916. 23917. How can multiple earth stations share a satellite on the same frequencies? 23918. 23919. Frequency reuse 23920. Multiplexing 23921. Mixing 23922. They can’t 23923. 23924. A navigation technique that determines position by extrapolating a series of measured velocity increments. 23925. 23926. Piloting 23927. Wandering 23928. Radio navigation 23929. Dead reckoning 23930. 23931. A geostationary satellite 23932. 23933. Is motionless in space (except for its gain) 23934. Is not really stationary at all, but orbits the Earth within a 24-hr period 23935. Appears stationary over the Earth’s magnetic pole 23936. Is located at a height of 35,800 km to ensure global coverage 23937. 23938. The average elevation of Navstar GPS satellite is ____ statue miles above the Earth. 23939. 23940. 6724 23941. 7689 23942. 5978 23943. 9476 23944. 23945. Most commercial satellite activity occurs in which band(s) 23946. 23947. L 23948. C and Ku 23949. X 23950. S and P 23951. 23952. Indicate the correct statement regarding satellite communications 23953. 23954. If two earth stations do not face a common satellite, they should communicate via a double-satellite hop. 23955. Satellites are allocated so that it is impossible for two earth stations not to face the same satellite. 23956. Collocated earth stations are used for frequency diversity. 23957. Satellite earth station must have as many receive chains as there are carriers transmitted to it. 23958. 23959. Satellite used for intercontinental communications are known as 23960. 23961. Comsat 23962. Domsat 23963. Marisat 23964. Intelsat 23965. 23966. Identical telephone numbers in different parts of the country are distinguished by their 23967. 23968. Language digits 23969. Access digits 23970. Area codes 23971. Central office codes 23972. 23973. The GPS satellites has an angle of elevation at the ascending node of ____ with respect to the equatorial plane. 23974. 23975. 30 degrees 23976. 55 degrees 23977. 50 degrees 23978. 45 degrees 23979. 23980. Telephone traffic is measured 23981. 23982. With echo cancellers 23983. By the relative congestion 23984. In terms of the grade of service 23985. In erlangs 23986. 23987. Indicate which of the following is not a submarine cable 23988. 23989. TAT-7 23990. INTELSAT V 23991. ATLANTIS 23992. CANTAT 2 23993. 23994. The typical bandwidth of a satellite band is 23995. 23996. 36 MHz 23997. 40 MHz 23998. 70 MHz 23999. 500 MHz 24000. 24001. The operational satellites of Navstar GPS are revolving around Earth in orbital planes are approximately ____ degrees apart with ____ satellites in each plane. 24002. 24003. 60, 4 24004. 30, 5 24005. 50, 5 24006. 40, 3 24007. 24008. Indicate which of the following is an American domsat system 24009. 24010. INTELSAT 24011. TELSTAR 24012. COMSAT 24013. INMARSAT 24014. 24015. Which of the following is not usually a part of a transponder? 24016. 24017. LNA 24018. Mixer 24019. Modulator 24020. HPA 24021. 24022. Who is the oldest man in space? 24023. 24024. John Glenn 24025. Neil Armstrong 24026. Yuri Gagarin 24027. Edwin Aldrin 24028. 24029. It refers to the satellite orientation with respect to the earth. 24030. 24031. Satellite’s attitude 24032. Satellite position 24033. Satellite location 24034. Satellite orbit 24035. 24036. Precise positioning service has time transfer accuracy to UTC within 24037. 24038. 100 nanoseconds 24039. 300 nanoseconds 24040. 200 nanoseconds 24041. 400 nanoseconds 24042. 24043. The fully deployed Galileo satellite system consists of ____ satellites. 24044. 24045. 27 operational + 3 active spares 24046. 26 operational + 4 active spares 24047. 28 operational + 2 active spares 24048. 25 operational + 5 active spares 24049. 24050. Galileo satellite is ____. 24051. 24052. Medium Earth Orbit (MEO) 24053. Low Earth Orbit (LEO) 24054. Geosynchronous Earth Orbit (GEO) 24055. Highly Elliptical Orbit (HEO) 24056. 24057. Galileo satellites are at circular planes at ____ altitude above Earth. 24058. 24059. 23,500 mi 24060. 36,500 km 24061. 35,800 mi 24062. 23,222 km 24063. 24064. Galileo satellites are inclined at the orbital planes of ____ with reference to the equatorial plane. 24065. 24066. 64 degrees 24067. 17 degrees 24068. 56 degrees 24069. 34 degrees 24070. 24071.

24072. 24073. 24074. 24075. 24076. 24077. 24078. 24079. 24080. 24081. 24082. 24083. 24084. 24085. 24086. 24087. 24088. 24089. 24090. 24091. 24092. 24093. MULTIPLE CHOICE QUESTIONS IN 24094. ANTENNA 24095. Electronics Systems and Technologies 24096. By 24097. Melvin C. Arceo 24098. 24099. 24100. 24101. 24102. 24103. 24104. 24105. 24106. 24107. 24108. 24109. ENCODED BY: 24110. LORENZO, Luer Breech B. 24111. It is a metallic conductor system capable of radiating and capturing electromagnetic energy. transmission lines antenna waveguides load 24112. 24113. A directional antenna with two or more elements is known as folded dipole ground plane loop array 24114. 24115. The ratio of the focal length to the diameter of the mouth of the parabola is called _____. aperture focal point foci major axis 24116. 24117. The impedance of a dipole is about 50-ohm 73-ohm 93-ohm 300-ohm 24118. 24119. A special type if transmission lint that consists of a conducting metallic tube through which high-frequency electromagnetic energy is propagated. medium microstrip stripline waveguide 24120. 24121. Calculate the angle of declination for an antenna using a polar mount at a latitude of 45 degrees. 3.2 degrees 1.3 degrees 4.2 degrees 6.81 degrees 24122. 24123. 24124. 24125. The cone angle of the flare angle of a conical horn antenna is approximately 55 degrees 45 degrees 40 degrees 50 degrees 24126. 24127. Electrical energy that has escaped into free space in the form of transverse electromagnetic waves radio waves frequency signal wavelength 24128. 24129. The length of the ground plane vertical at 146 MHz is 1.6 ft. 1.68 ft. 2.05 ft. 3.37 ft. 24130. 24131. Using a small reflector to beam waves to the larger parabolic reflector is known as focal feed horn feed cassegrain feed coax feed 24132. 24133. The plane parallel to the mutually perpendicular line in the electric and magnetic fields is called _____ wavefront point source isotropic source rays 24134. 24135. What is the beamwidth of a parabolic antenna with a diameter of 5 meters and an operating frequency to 10 GHz? 0.5 degrees 0.675 degrees 0.348 degrees 3.48 degrees 24136. 24137. 24138. The horizontal radiation pattern of a dipole is a circle figure of eight clover leaf narrow beam 24139. 24140. The size of the antenna is inversely proportional to _____ frequency power radiation resistance wavelength 24141. 24142. A popular half-wavelength antenna is the ground plane end-fire collinear dipole 24143. 24144. Calculate the gain of a parabolic antenna using a 2.5-m radius dish operating at 10 GHz. 166.673 dB 83.7 dB 52.2 dB 45.6 dB 24145. 24146. It is the ratio of the radiated to the reflected energy radiation resistance radiation efficiency radiation constant radiation antenna 24147. 24148. The feed mechanism in a parabolic antenna that radiates the electromagnetic energy primary antenna reflectors secondary antenna focal point 24149. 24150. 24151. 24152. 24153. 24154. It is a polar diagram representing field strengths or power densities at various angular relative to an antenna sidelobe front lobe radiation pattern radiation constant 24155. 24156. For a transmit antenna with a radiation resistance of 72 ohms, an effective antenna resistance of 8 ohms, a directivity gain of 20 and an input power of 100W, determine the antenna gain. 12.55 dB 10.43 dB 11.21 dB 9.78 dB 24157. 24158. The radiation pattern plotted in terms of electric field strength or power density absolute radiation pattern relative radiation pattern absolute front lobe pattern absolute sidelobe pattern 24159. 24160. Calculate the characteristic impedance of a quarter-wavelength section used to connect a 300-ohm antenna to a 75-ohm line 150 ohms 120 ohms 130 ohms 110 ohms 24161. 24162. Plots of field strength or power density with respect to the value at a reference point absolute frontlobe pattern relative radiation pattern relative frontlobe pattern relative radiation pattern 24163. 24164. What must be the height nof a vertical radiator one-half wavelength high if the operating frequency is 1100 kHz? 120 m 136 m 115 m 124 m 24165. 24166. Lobes adjacent to the front lobe diagonal lobes side lobes front lobes back lobes 24167. 24168. Lobes in a directional exactly opposite of the front lobe side lobes adjacent lobes front lobes back lobes 24169. 24170. Calculate the efficiency of an antenna that has a radiation resistance of 73 ohms and an effective dissipation resistance of 5 ohms. 98.3 % 93.6 % 90.7 % 95.5 % 24171. 24172. The line bisecting the major lobe, or pointing from the center of the antenna in the direction of maximum radiation is called _____. line of shoot diagonal shoot bisecting shoot antenna shoot 24173. 24174. The ammeter connected at the base of a Marconi antenna has a certain reading. If this reading is increased 2.77 times, what is the increase in output power? 3.45 1.89 2.35 7.67 24175. 24176. Refers to a field pattern that is close to the antenna induction field far field radiation capture field 24177. 24178. A half-wave dipole is driven a 5-W signal at 225MHz. A receiving dipole 100 km. Calculate the received power into a 73-ohm receiver. 23.5 pW 7.57 pW 5.64 pW 1.26 pW 24179. 24180. It is the resistance that, if it replaced the antenna, would dissipate exactly the same amount of power that the antenna radiates. directivity gain antenna efficiency radiation resistance antenna resistance 24181. 24182. What is the effective radiated power of a television broadcast station if the output of the transmitter is 1000W, antenna transmission line loss is 50W, and the antenna power gain is 3. 1250 W 2370 W 2130 W 2850 W 24183. 24184. It is the ratio of the power radiated by an antenna to the sum of the power radiated and the power dissipated. radiation resistance coupling resistance antenna efficiency antenna beamwidth 24185. 24186. It is the ratio of the power radiated by the antenna to the total input power. antenna efficiency reflection coefficient standing wave ratio radiation resistance 24187. 24188. 24189. 24190. 24191. 24192. If a 500-kHz transmitter of a constant power produces field strength of 100 µV/m at a distance of 100 mil from the transmitter, what would be the field strength at a distance of 200 mi from the transmitter? 45µV/m 100 µV/m 50 µV/m 35 µV/m 24193. 24194. An antenna that transmits or receives equally well in all directions is said to be ______. omnidirectional bi-directional unidirectional quadsidirectional 24195. 24196. It is the ratio of the power density radiated in a particular direction to the power density radiated to the same point by a reference antenna, assuming both antennas are radiating the same amount of power. power gain directive gain total gain system gain 24197. 24198. If the field intensity of 25 mV/m develops 2.7 V in a certain antenna, what is its effective height? 110 m 100 m 98 m 108 m 24199. 24200. The magnetic field of an antenna is perpendicular to the earth. The antenna’s polarization ______. is vertical is horizontal is circular cannot be determined from the information given 24201. 24202. 24203. 24204. 24205. If the power of a 500-kHz transmitter is increased from 150W to 300W, what would be the percentage change in field intensity at a given distance from the transmitter? 141 % 150 % 100 % 133 % 24206. 24207. It is the same with directive gain except that the total power fed to the antenna is used and the antenna efficiency is taken into account. system gain power gain directive gain total gain 24208. 24209. A ship-radio telephone transmitter operates on 2738 kHz. At a certain point distant from the transmitter, the 2738-kHz signal is measured field at 147 mV/m, the second harmonic field at the same decibels, how much has the harmonic emission been attenuated below the 2738-kHz fundamental? 43.2 dB 51.2 dB 35.1 dB 25.1 dB 24210. 24211. It is the equivalent power that an isotropic antenna would have to radiate to achieve the same power density in the chosen direction at a given point as another antenna. EIRP ERP IRL RSL 24212. 24213. When energy is applied to the antenna at a point of high-circulating current. voltage-fed antenna power-fed antenna current-fed antenna impedance-fed antenna 24214. 24215. 24216. 24217. 24218. For a transmitter antenna with a power gain of 10 and an input power of 100W, determine the EIRP in watts. 30 dBW 40 dBW 50 dBW 20 dBW’ 24219. 24220. If the energy is applied at the geometrical center of antenna, the antenna is said to be ______. center-fed end-fed quarterwave-fed halfwave-fed 24221. 24222. For a transmit antenna with a power gain of 10 and an input power of 100W, determine the power density at a point 10 km from the transmit antenna 0.574 µW/m2 0.796 µW/m2 1.24 µW/m2 0.981 µW/m2 24223. 24224. For a transmit antenna with a radiation resistance of 72 ohms, an effective antenna resistance of 8 ohms, a directive gain of 20 and an input power of 100W, determine the antenna efficiency. 90 % 96 % 98 % 96 % 24225. 24226. The field surrounding the antenna do not collapse their energy back into the antenna but rather radiate it out into space. induction field near field radiation field magnetic field 24227. 24228. 24229. 24230. 24231. For receive power density of 10µW/m2 and a receive antenna with a capture area of 0.2 m2, determine the captured power. 0.5 µW 2 µW 1 µW 1.5 µW 24232. 24233. The property of interchangeability for the transmitting and receiving operations is known as _____. efficiency accuracy reciprocity polarization 24234. 24235. The length of a doublet at 27 MHz is _____. 8.67 ft. 17.3 ft. 18.2 ft. 34.67 ft. 24236. 24237. Refers to the orientation of the electric field radiated from an antenna. efficiency beamwidth polarization accuracy 24238. 24239. At frequencies below 2 MHz, what type of antenna is usually used? Marconi antenna Hertzian antenna Herzt antenna Elementary doublet 24240. 24241. The angular separation between two half-power points in the major lobe of the antenna’s plane radiation pattern. bandwidth polarization efficiency beamwidth 24242. 24243. 24244. Hertz antenna are predominantly used with frequencies above 3 MHz 4 MHz 5 MHz 2 MHz 24245. 24246. Defined as the frequency range over which antenna operation is satisfactory. beamwidth channel bandwidth baseband 24247. 24248. One of the following is not a omnidirectional antenna. half-wave dipole log-periodic discone marconi 24249. 24250. The point on the antenna where the transmission line is connected is called _____. center feed end feed feedpoint voltage feed 24251. 24252. A popular vertical antenna is the _____. collinear dipole ground plane broadside 24253. 24254. The discone antenna is a useful direction-finding antenna used as a radar receiving antenna circularly polarized like other circular antennas useful as a UHF receiving antenna 24255. 24256. 24257. 24258. 24259. 24260. The feedpoint presents and ac load to the transmission line called antenna output impedance antenna input impedance feedpoint impedance center feed impedance 24261. 24262. A helical antenna is used for satellite tracking because of its circular polarization maneuverability broad bandwidth good front to back ratio 24263. 24264. The simplest type of antenna elementary doublet half-wave dipole quarterwave dipole 5/8 wavelength dipole 24265. 24266. Zoning is used with a dielectric antenna in order to reduce the bulk of the lens increase the bandwidth of the lens permit pin-point focusing correct the curvature of the wavefront from a horn that is too short 24267. 24268. It is an electrically short dipole. short dipole quarterwave dipole half-wave dipole yagi antenna 24269. 24270. Cassegrain feed is used with parabolic reflector to increase the gain of the system increase the bandwidth of the system reduce the size of the main reflector allow the feed to be placed at a convenient point 24271. 24272. 24273. 24274. 24275. 24276. The half-wave dipole is generally referred to as ______. Yagi antenna Hertzian antenna Marconi antenna Hertz antenna 24277. 24278. Top loading is sometimes used with an antenna in order to increase its effective height bandwidth beamwidth input capacitance 24279. 24280. What is the directivity of a Hertz antenna? 1.64 2.18 2.15 1.75 24281. 24282. The standard reference antenna for the directive gain is the _____. infinitesimal dipole isotropic antenna elementary doublet half-wave dipole 24283. 24284. An antenna which is one-quarter wavelength long, mounted vertically with the lower end either connected directly to ground or grounded through the antenna coupling network. loop antenna hertzian antenna monopole antenna turnstile antenna 24285. 24286. An antenna that is circularly polarized is the helical small circular loop parabolic reflector Yagi-Uda 24287. 24288. 24289. 24290. 24291. It is a wire structure placed below the antenna and erected above the ground. ground plane counterpoise ground lines top hat 24292. 24293. Which of the following terms does not apply to the Yagi-Uda array good bandwidth parasitic elements folded dipole high gain 24294. 24295. It effectively cancels out the capacitance component of the antenna input impedance. ground plane top hat loading coil shunt capacitance 24296. 24297. Indicate which of the following reasons for the use of an earth mat with antennas is false: impossibility of a good ground conduction provision of an earth for the antenna protection of personnel working underneath improvement of the radiation pattern of the antenna 24298. 24299. A metallic array that resembles a spoke wheel placed at the top of an antenna, it increases the shunt capacitance to ground reducing the overall antenna capacitance. loading coil top loading series capacitance series inductors 24300. 24301. Indicate the antenna that is not wideband; discone folded dipole helical Marconi 24302. 24303. 24304. 24305. 24306. It is formed when two or more antenna elements are combined to form a single antenna. antenna elements antenna arrays driven elements parasitic elements 24307. 24308. One of the following is not a reason for the use of an antenna coupler: to make the antenna look resistive to provide the output amplifier with the correct load impedance to discriminate against harmonics to prevent reradiation of local oscillators 24309. 24310. It is an individual radiator, such as half or quarter-wave dipole antenna element antenna array reflector director 24311. 24312. Indicate which of the following reasons for using counterpoise with antennas is false: impossibility of a good ground connection protection of personnel working underneath provision of an earth for the antenna rockiness of the ground itself 24313. 24314. Type of antenna element that is directly connected to the transmission lines and receives from or is driven by the source. driven array parasitic array driven element parasitic element 24315. 24316. Which of the following antennas is best excited from a waveguide? biconical horn helical discone 24317. 24318. 24319. 24320. 24321. Type of antenna element that is not connected to the transmission lines. parasitic array driven array parasitic array parasitic element 24322. 24323. One of the following is very useful as a multiband HF receiving antenna. This is the: conical horn folded dipole log-periodic square loop 24324. 24325. A parasitic element that is longer than the driven element from which it receives energy. driven element director parasitic element reflector 24326. 24327. One of the following consists of nonresonant antennas. rhombic antenna folded-dipole antenna end-fire antenna broadside antenna 24328. 24329. A parasitic element that is shorter than its associated driven element. redirector director reflector parasitic element 24330. 24331. An ungrounded antenna near the ground. acts as a single antenna near the ground is unlikely to need an earth mat acts as an antenna array must be horizontally polarized 24332. 24333. 24334. 24335. 24336. It is a non resonant antenna capable of operating satisfactory over a relatively wide bandwidth, making it ideally suited for HF transmission. turnstile antenna loop antenna rhombic antenna discone antenna 24337. 24338. A wide-bandwidth multielement driven array is the _____. end-fire log-periodic yagi collinear 24339. 24340. It is a linear array antenna consisting of a dipole and two or more parasitic elements: one reflector and one director. broadside antenna end-fire antenna yagi-uda antenna phased array antenna 24341. 24342. An antenna which is consists of a cone that is truncated in a piece of circular waveguide. pyramidal horn antenna circular horn antenna rectangular horn antenna conical horn antenna 24343. 24344. Which antenna has a unidirectional radiation pattern and gain? dipole ground plane yagi collinear 24345. 24346. An antenna formed by placing two dipoles at right angles to each other, 90 degrees out of phase. discone antenna turnstile antenna bicone antenna 5/8 wavelength shaped 24347. 24348. 24349. The radiation pattern of collinear and broadside antennas is _____. omnidirectional bi-directional unidirectional clover-leaf shaped 24350. 24351. What is the bandwidth ratio of log-periodic antenna? 10:1 5:1 20:1 1:10 24352. 24353. Which beam width represents the best antenna directivity 7 degrees 12 degrees 19 degrees 28 degrees 24354. 24355. It is a ration of the highest to the lowest frequency over which n antenna will satisfactoru operate. channel ratio bandwidth ratio reflection ratio dynamic range 24356. 24357. An antenna has a power gain of 15. The power applied to the antenna is 32 W. The effective radiated power is ______. 15 W 32 W 120 W 480 W 24358. 24359. It is simply a single-turn coil of wire that is significantly shorter than one wavelength and carries RF current. turnstile antenna loop antenna rhombic antenna long-wire antenna 24360. 24361. 24362. A coax has an attenuation of 2.4 dB per 100 ft. The attenuation of 275 ft. 2.4 dB 3.3 dB 4.8 dB 6.6 dB 24363. 24364. It is a group of antennas or group of antenna arrays that when connected together, function as a simple whose beamwidth and direction can be changed electronically withour having to physically move any of the individual antennas or antenna elements within the array. end fire antenna broadside antenna phased array antenna log-periodic antenna 24365. 24366. Conductors in multielement antennas that do not receive energy directly from the transmission line are known as ______. parasitic element driven element the boom receptor 24367. 24368. It is a broad VHF or UHF antenna that is suited for applications for which radiating circular rather than horizontal or vertical polarized electromagnetic waved are required discone antenna bicone antenna log-periodic antenna helical antenna 24369. 24370. Mode of propagation of helical antennas where electromagnetic radiation is in the direction at right angles to the axis of the helix. normal mode axial mode helix mode helical mode 24371. 24372. 24373. 24374. 24375. Mode of propagation of helical antennas where radiation of the antenna in the axial direction and produces a broadband relatively directional pattern helical mode normal mode axial mode helix mode 24376. 24377. In a Yagi antenna, maximum direction of radiation is toward the director driven element reflector sky 24378. 24379. It is defined as the ratio of the antenna maximum gain in the forward direction to its maximum gain in its backward direction. side-to-back ratio front-to-side ratio back-to-side ratio front-to-back ratio 24380. 24381. The horizontal radiation pattern of a vertical dipole is a _____. figure of eight circle narrow beam clover leaf 24382. 24383. An antenna that provides extremely high gain and directivity and very popular for microwave radio and satellite communications link helical antenna parabolic antenna hyperbolic antenna log-periodic antenna 24384. 24385. Part of a parabolic antenna that houses the primary antenna which radiates electromagnetic waves toward the reflector. feed mechanism focal point center feed feed antenna 24386. It is a passive device that simply reflects the energy radiated by the feed mechanism into a concentrated, highly directional emission in which the individual waved are all in phase with each other. director parabolic segment reflector feed mechanism 24387. 24388. The energy near the edge of the parabolic dish that does not reflect but rather is diffracted around the edge of the dish. spillover corona dissipated power copper loss 24389. 24390. Determines the angular aperture of the reflector, which indirectly determines how much the primary radiation is reflected by the parabolic dish. numerical aperture V number aperture number aperture angle 24391. 24392. For a 2-m diameter parabolic reflector with 10W of power radiated by the feed mechanism operating at 6 GHz with transmit antenna efficiency of 55 % and an aperture efficiency of 55 % determine the beamwidth. 1.25 degrees 2.25 degrees 1.5 degrees 1.75 degrees 24393. 24394. Type of lead mechanism where the primary radiating source is located just behind a small opening at the vertex of the paraboloid rather than at the focus. cassegrain feed center feed horn feed antenna feed 24395. 24396. 24397. 24398. 24399. Discone radiation pattern is omnidirectional unidirectional figure of eight bi-directional 24400. 24401. Which is properly terminated antenna? dipole marconi hertz rhombic 24402. 24403. An example of a Marconi antenna is _____. quarter wave vertical tower collinear yagi rhombic 24404. 24405. At the ends of a half-wave antenna, what values of current and voltage exist compared to the remainder of the antenna? minimum voltage and maximum current minimum voltage and minimum current equal voltage and current maximum voltage and minimum current 24406. 24407. Radiation resistance is the ratio of ______. radiated power to antenna center current radiated power to the square of the antenna center current voltage to any point of the antenna square of voltage to thesquare of current at any point in the antenna 24408. 24409. Consists of basic antenna connected to a transmission line plus one or more additional conductors parasitic array directors driven array reflectors 24410. 24411. 24412. 24413. Which of the following is not a driven array yagi broadside collinear end fire 24414. 24415. What is used to determine phase difference between two broadcast antennas? a phase monitor a frequency monitor an amplitude monitor a power monitor 24416. 24417. In antennas, which gives more forward gain? reflector driven element parasitic element director 24418. 24419. Which of the following is longer? director reflector driven element parasitic element 24420. 24421. Which is closer to the driven element? parasitic element driven element director reflector 24422. 24423. How much do they differ in length from a half-wavelength? 5% 10% 15% 20% 24424. 24425. 24426. 24427. 24428. 24429. How much move feed-point impedance does a folded-dipole have than normal dipole? two times as much three times as much four times as much five times as much 24430. 24431. How is it possible to produce 70-ohm twin lead? by folding more parasitic element by manufacturing by increasing the radiation resistance by increasing the length of the antenna 24432. 24433. With similar size parabolic, plane reflector, and corner-reflector beams, which has greates gain? plane reflector parabolic corner-reflector beam V-beam 24434. 24435. With similar size, which has the narrowest lobes? parabolic V-beam corner-reflector beam plane reflector 24436. 24437. Why would the wires of V beam be closer together when used on higher frequencies? main lobe lays further to wire main lobe lays closer to wire secondary lobes closer to wire secondary lobes further to wire 24438. 24439. How is the V-beam made unidirectional? impedance terminated capacitive terminated inductive terminated resistor terminated 24440. 24441. 24442. 24443. 24444. Why might a rhombic be better than a V-beam? it is resistor terminated more acreage needed less acreage needed it is unidirectional 24445. 24446. Why is it usual rhombic nor frequency-sensitive? unidirectional terminated with its characteristic impedance less acreage required main lobe is greater than back lobe 24447. 24448. In what direction is the null of small diameter loop in relation to the plane of the loop? 45 degrees angle 180 degrees angle 360 degrees angle 90 degrees angle 24449. 24450. When is a loop unidirectional? when horizontal when vertical when circular when unidirectional 24451. 24452. Why are verticals sometimes top-loaded? to resonate on high frequency to decrease the electrical length to resonate on low frequency to look better 24453. 24454. Why is pi-network superior to direct coupling to an antenna? reduce harmonic radiation better frequency response better radiation of energy reduce power dissipation 24455. 24456. 24457. 24458. 24459. 24460. Why might L networks be used between an antenna and transmission line? step impedance up step impedance down better radiation of energy reduce power radiation 24461. 24462. Why are antenna ammeters often shorted out or disconnected from the antenna expect when readings are desired? to replace it with dummy not to interfere with transmission for proper reception of signals to protect from lightning 24463. 24464. Device to split transmission line current to two or more antenna towers splitter coupler isolator phasor circuit 24465. 24466. What method can be used to determine the feed-point impedance of a vertical antenna? resistance substitution impedance matching dissipated resistance measurement grounding the antenna 24467. 24468. In what unit is field intensity measured/ volts amperes watts/m mV/m 24469. 24470. How fast does low-frequency field strength attenuate? directly proportional to distance inversely proportional to distance directly proportional to time inversely proportional to time 24471. 24472. 24473. 24474. Under what condition might a harmonic of a transmission be heard at a distant point when the fundamental cannot be? when the carrier is weak when fundamental is too weak when harmonics are weak when the harmonics are amplified 24475. 24476. Field gain can be measured in ______. volts dB ohms both volts and dB 24477. 24478. What is involved in the ERP of an antenna? input power times field gain input power squared times field gain output power times field gain output power squared times field gain 24479. 24480. Why do ground radials assure constant feed-point impedance? virtual ground constant in any weather ensure strength of signals produce a signal image creates good ground 24481. 24482. What feed requirements must be met to produce a circular radiation pattern when using two crossed dipoles? feed 180degrees apart electrically feed 45 degrees apart electrically feed 360 degrees apart electrically feed 90 degrees apart electrically 24483. 24484. A section which would be a complete antenna by itself bay reflector paraboloid hyperboloid 24485. 24486. 24487. In what range of frequencies are most omnidirectional horizontally polarized antennas used? VHF and UHF HF and VHF UHF and HF LF and MF 24488.

24489. 24490. 24491. 24492. 24493. 24494. 24495. 24496. 24497. 24498. 24499. 24500. 24501. 24502. 24503. 24504. 24505. 24506. 24507. 24508. 24509. 24510. MULTIPLE CHOICE QUESTIONS IN 24511. MICROWAVE COMMUNICATIONS 24512. Electronics Systems and Technologies 24513. By 24514. Melvin C. Arceo 24515. 24516. 24517. 24518. 24519. 24520. 24521. 24522. 24523. 24524. ENCODED BY: 24525. LORENZO, Luer Breech B. 24526. IF repeaters are also called heterodyne receiver mixer/receiver radio receiver FM receiver 24527. 24528. It is the difference between the nominal output power of a transmitter and the minimum input power required by a receiver RSL IRL system gain FSL 24529. 24530. A phenomenon whereby the frequency of a reflected of a reflected signal is shifted if there is relative motion between the source and reflecting object. Doppler effect Hall effect Marconi effect Maxwell effect 24531. 24532. A ferrite is a nonconductor with magnetic properties an intermetallic compound with particularly good conductivity an insulator which heavily attenuates magnetic fields a microwave semiconductor invented by Faraday 24533. 24534. The primary purpose of the helix in a traveling-wave tube is to prevent the electron beam from spreading in the long tube reduce the axial velocity of the RF field ensure the broadband operation reduce the noise figure 24535. 24536. The attenuator is used in the travelling-wave tube to help bunching prevent oscillations prevent saturation increase the gain 24537. 24538. 24539. 24540. A magnetron is used only as amplifier oscillator mixer frequency multiplier 24541. 24542. A backward-wave oscillator is based on the rising-sun magnetron crossed-field amplifier coaxial magnetron traveling-wave tube 24543. 24544. Stripline and microstrip transmission lines are usually made with coax parallel lines twisted pair PCBs 24545. 24546. Which of the following is not a microwave tube? Traveling-wave tube Cathode-ray tube Klystron Magnetron 24547. 24548. Indicate which is not true. Compared with other types of radar, phased array radar has the following advantages very fast scanning ability to track and scan simultaneously circuit simplicity ability to track many targets simultaneously 24549. 24550. Given the frequency and dimensions of 5 GHz and 7 cm by 9 cm respectively, the beam of the pyramidal horn is about ______. 27 degrees 53 degrees 60 degrees 80 degrees 24551. 24552. 24553. The diameter of a parabolic reflector should be at least how many wavelengths at the operating frequency? 1 2 5 10 24554. 24555. A type of microwave repeater where the received RF carrier is down-converted to an IF frequency, amplified filtered and further demodulated to baseband. RF repeater IF repeater baseband repeater radio repeater 24556. 24557. In order to reduce cross-sectional dimensions, the waveguide to use is circular ridged rectangular flexible 24558. 24559. Indicate which one of the following applications or advantages of radar beacons is false: target identification navigation very significant extension of the maximum range more accurate tracking enemy targets 24560. 24561. Refers to more than one transmission path or method of transmission available between transmitter and a receiver. diversity polarization efficiency accuracy 24562. 24563. A solution to the “blind speed” problem is to change the Doppler frequency vary the RF use monopulse use MTI 24564. 24565. 24566. A direct path that exist between the transmit and receive antennas LOS direct waves space waves terrestrial waves 24567. 24568. The function of the quartz delay line in an MTI radar is to help in subtracting a complete scan from the previous scan match the phase of the coho and the stalo match the phase of the coho and the output oscillator delay a sweep so that the next sweep can be subtracted from it 24569. 24570. Type of diversity where it modulates two different RF carrier frequencies with the same IF intelligence, then transmitting both RF signals to a given destination. polarization diversity quad diversity space diversity frequency diversity 24571. 24572. The coho in MTI radar operates at the intermediate frequency transmitted frequency received-frequency pulse operation frequency 24573. 24574. Which type of diode does not ordinarily operate with reverse bias? Varactor IMPATT Snapp-off Tunnel 24575. 24576. What happens when a horn antenna is made longer? gain increases beam width decreases bandwidth increases bandwidth decreases 24577. 24578. 24579. 24580. 24581. A pyramidal horn used at 5 GHz has an aperture that is 7 cm by 9 cm. The gain is about 10.5 dB 11.1 dB 22.6 dB 35.8 dB 24582. 24583. Type of diversity where the output of the transmitter is fed to two or more antennas that are physically separated by an appreciable wavelengths quad diversity wavelength diversity space diversity hybrid diversity 24584. 24585. The Doppler effect is used in (indicate the false statement) moving-target plotting on the PPI the MTI system FM radar CW radar 24586. 24587. A type of diversity where a single RF carrier is propagated with two different electromagnetic polarization. space diversity wavelength diversity polarization diversity hybrid diversity 24588. 24589. The A scope displays the target position and range the target range, but not position the target position, but not range neither range nor position, but only velocity 24590. 24591. The glass tube of a TWT may be coated with aquadag to help focusing provide attenuation improve bunching increase gain 24592. 24593. Type of diversity which consists of a standard frequency diversity path where the two transmitter/receiver pair at one end of the path are separated from each other and connected to different antennas that are vertically separated as in space diversity quad diversity wavelength diversity space diversity hybrid diversity 24594. 24595. The biggest disadvantage of CW Doppler radar is that it does not give the target velocity it does not give the target range a transponder is required at the target it does not give the target position 24596. 24597. The combination of the frequency, space, polarization and receiver diversity into one system hybrid diversity quad diversity space diversity wavelength diversity 24598. 24599. If the target cross section is changing, the best system for accurate tracking in lobe switching sequential lobing conical switching monopulse 24600. 24601. The multicavity klystron is not good low-level amplifier because of noise has a high repeller voltage to ensure a rapid transmit time is not suitable for pulse operation needs a long transmit time through the buncher cavity to ensure current modulation 24602. 24603. An arrangement that avoids a service interruption during periods of deep fades or equipment failures. service switching arrangement protection switching arrangement interruption switching arrangement equipment switching arrangement 24604. 24605. A type of attenuator where attenuation is accomplished by insertion of a thin card of resistive material through a slot in the top of a waveguide flap attenuator vane attenuator slot attenuator directional coupler 24606. 24607. After a target has been acquired, the best scanning system for tracking is nodding spiral conical helical 24608. 24609. A duplexer is used to couple two different antennas to a transmitter without mutual interference to allow the one antenna to be used for reception or transmission without mutual interference to prevent interference between two antennas when they are connected to a receiver to increase the speed of pulses in pulsed radar 24610. 24611. Type of protection switching arrangement where each working radio channel has a dedicated backup or spare channel hot swap hot backup hot standby hot diversity 24612. 24613. If a return echo arrives after the allocated pulse interval, it will interfere with the operation of the transmitter the receiver might be overloaded it will not be received the target will appear closer than it really is 24614. 24615. Points in the microwave system baseband signals either originate or terminate terminator terminal stations terminating equipment terminal equipment 24616. 24617. A half wavelength, closed section of a waveguide that acts as a parallel resonant circuit is known as _____. half-wave section cavity resonator LCR circuit directional couple 24618. 24619. Decreasing the volume of a cavity causes its resonant frequency to increase decrease remains the same drop to zero 24620. 24621. The IF bandwidth of a radar receiver is inversely proportional to the pulse width pulse repetition frequency pulse interval the target will appear closer than it really is 24622. 24623. Which of the following devices are not being used in microwave power amplifier? klystron tubes traveling wave tubes IMPATT magnetron 24624. 24625. Which is not true? A high PRF will make the returned echoes easier to distinguish from noise make the target tracking easier with conical scanning increase the maximum range have no effect on the range resolution 24626. 24627. It is a unidirectional device often made up of ferrite material used in conjunction with a channel-combining network to prevent the output from interfering with the output of another transmitter circulator magic tee isolator rat race 24628. 24629. Which is not true about the following: Flat-topped rectangular pulses must be transmitted in radar to allow a good minimum range make the returned echoes easier to distinguish from the noise prevent frequency changes in the magnetron allow accurate range measurements 24630. 24631. The power that leaks out of the back and sides of the transmit antenna interfering with the signal entering with the signal entering the input of a nearby receive antenna. ringaround ringabout roundabout turnaround 24632. 24633. Which of the following is not true: The radar cross section of a target depends on the frequency used may be reduced by special coating of the target depends on the aspect of a target, if this nonspherical is equal to the actual cross-sectional area for small targets 24634. 24635. It is a general term applied to the reduction in signal strength at the input to a receiver fading attenuation absorption ghosting 24636. 24637. Indicate which of the following cannot be followed by the word “waveguide” elliptical flexible coaxial ridged 24638. 24639. If the ratio of the antenna diameter to the wavelength in a radar system is high, this will result in (indicate the false statement) large maximum range good target discrimination difficult target acquisition increased capture area 24640. 24641. 24642. High-power TWTs are replacing what in microwave amplifiers? MESFETs Magnetrons Klystrons IMPATT diodes 24643. 24644. The most widely used microwave antenna is a half-wave dipole quarter-wave probe single loop horn 24645. 24646. Applies to propagation variables in the physical radio path which affect changes in path loss between the transmitter at one station and its normal receiver at the other station. ghosting absorption attenuation fading 24647. 24648. If the antenna diameter in a radar system is increased by a factor of 4, the maximum range will be increased by a factor of square root of 2 2 4 8 24649. 24650. If the peak transmitted power in a radar system is increased by a factor of 15, the maximum range will be increased by a factor of 2 4 8 16 24651. 24652. Varactor and step-recovery diodes are widely used in what type of circuit? amplifier oscillator frequency multiplier mixer 24653. 24654. It is defined as line loss incurred by an electromagnetic wave as it propagates in a straight line through a vacuum with no absorption or reflection of energy from nearby objects. IRL FSL RSL Eb/No 24655. 24656. For proper operation, a magnetron must be accompanied by a cavity resonator strong electric field permanent magnet high dc voltage 24657. 24658. A police radar speed trap functions at a frequency of 1.024 GHz in direct line with your car. The reflected energy from your car is shifted 275 Hz in frequency. Calculate the speed in miles per hour? 60 mph 70 mph 80 mph 90 mph 24659. 24660. It is the ratio of the wideband carrier to the wideband noise power carrier to noise ratio signal to noise ratio energy per bit per noise density ratio noise figure 24661. 24662. What is the duty cycle of a radar pulse if the pulse width is 1µs, the pulse repetition rate is 900, and the average power is 18 W? 0.09 % 0.99 % 0.90 % 1.00 % 24663. 24664. A microwave tube amplifier uses an axial magnetic field and a radial electric field. This is the reflex klystron coaxial magnetron traveling-wave magnetron CFA 24665. Figure of merit used to indicate how much the signal-to-noise ratio deteriorates as a signal passes through a circuit or series of circuits noise factor signal to noise ratio carrier to noise ratio dynamic range 24666. 24667. What is the peak power of a radar pulse if the pulse width is 1µs, the pulse repetition rate is 900, and the average power is 18 W? 10 kW 15 kW 20 kW 30 kW 24668. 24669. The point where the antenna is mounted with respect to the parabolic reflector is called the focal point center locus tangent 24670. 24671. The operating frequency of klystron and magnetrons is set by the cavity resonators DC supply voltage inputsignal frequency Number of cavities 24672. 24673. Using a small reflector to beam waves to the larger parabolic reflector is known as focal feed horn feed cassegrain feed coax feed 24674. 24675. If the noise figures and gains of each of the amplifiers in cascade is 3 dB and 10 dB respectively. What is the total noise figure? 2.12 dB 3.24 dB 1.24 dB 4.23 dB 24676. 24677. 24678. One of the following is unlikely to be used as a pulsed device multicavity klystron BWO CFA TWT 24679. 24680. Calculate the maximum ambiguous range for a radar system with PRT equal to 400µs. 13.8 mi 43.5 mi 16.4 mi 32.8 mi 24681. 24682. When electromagnetic waves are propagated in a waveguide they travel along the broader walls of the guide they are reflected from the walls but do not travel along them they travel through the dielectric without the walls they travel along all four walls of the waveguide 24683. 24684. What is the distance in nautical miles to a target if it takes 123 µs for a radar pulse to travel from the radar antenna to the target, back to the antenna, and be displayed on the PPI scope? 10 nmi 5 nmi 20 nmi 15 nmi 24685. 24686. Waveguides are used mainly for microwave signals because they depend on straight-line propagation which applies to microwaves only losses would be too heavy at lower frequencies there are no generators powerful enough to excite them at lower frequencies they would be too bulky at lower frequencies 24687. 24688. Calculate the coupling of a directional coupler that has 70 mW into the main guide and 0.35 mW out the secondary guide. 13 dB 23 dB 33 dB 10 dB 24689. 24690. 24691. 24692. The wavelength of a wave in a waveguide is greater than in free space depends only on the waveguide dimensions and the free space wavelength is inversely proportional to the phase velocity is directly proportional to the group velocity 24693. 24694. A rectangular waveguide is 1 cm by 2 cm. Calculate the cutoff frequency 3.5 GHz 15 GHz 7.5 GHz 4 GHz 24695. 24696. The main difference between the operation of transmission liners and waveguides is that the latter is not distributed, like transmission lines the former can use stubs and quarter-wave transformers, unlike the latter transmission lines use the principal mode of propagation, and therefore do not suffer from low-frequency cut-off terms such as impedance matching and standing-wave ratio cannot be applied to waveguides 24697. 24698. The useful power of the transmitter that is contained in the radiated pulses is termed as ______. rms power rated power peak power average power 24699. 24700. In radars, echoes that are produced when the reflected beam is strong enough to make a second trip double range echoes double frequencies echoes second return echoes second time around echoes 24701. 24702. Indicate the false statement. Compared with equivalent transmission lines, 3 GHz waveguides are less lossy can carry higher powers are less bulky have lower attenuation 24703. The range beyond which targets appear as second return echoes is called maximum range maximum unambiguous range maximum usable range any of these 24704. 24705. When a particular mode is excited in a waveguide, there appears an extra electric component, in the direction of propagation. The resulting mode is transverse electric transverse magnetic longitudinal transverse-electromagnetic 24706. 24707. In radars, echoes that arrive after the transmission of the next pulse are called _____. second return echoes second time around echoes multiple time around echoes any of these 24708. 24709. When electromagnetic waves are reflected at an angle from a wall, their wavelength along the wall is the same as the free space the same as the wavelength perpendicular to the wall shortened because of the Doppler effect greater than in the actual direction of propagation 24710. 24711. A radar mile is equivalent to 2000 mi 2000 m 2000 yd 2000 km 24712. 24713. As a result of reflections from a plane conducting wall, electromagnetic waves acquire an apparent velocity of light in space velocity of propagation normal velocity group velocity phase velocity 24714. 24715. 24716. In radars, the time between pulses is called ______. rest time duration time delay time propagation time 24717. 24718. Indicate the false statement. When the free-space wavelength of a signal equals the cutoff wavelength of the guide the group velocity of the signal becomes zero the phase velocity of the signal becomes infinite the characteristic impedance of the guide becomes infinite the wavelength within the waveguide becomes infinite 24719. 24720. In radars, the duration of the pulse is duty cycle pulse width pulse amplitude pulse cycle 24721. 24722. A signal propagated in a waveguide has a full wave electric intensity change between two further walls, and no component of the electric field in the direction of propagation. The mode is TE11 TE10 TM22 TE20 24723. 24724. In radars, the number of the pulses transmitted per second is called pulse repetition frequency pulse repetition time pulse repetition phase pulse number of repetition 24725. 24726. Which of the following is incorrect? The dominant mode of propagation is preferred with rectangular waveguides because it leads to the smallest waveguide dimensions the resulting impedance can be matched directly to coaxial lines it is easier to excite than other modes propagation of it without any spurious generation can be ensured 24727. It is a mean of employing radio waves to detect and locate objects such as aircraft, ships and land masses. detectors radars repeaters beacons 24728. 24729. A choke flange may be used to couple two waveguides to help the alignment of the waveguides because it is simpler than any other join to compensate for discontinuities at the join to increase the bandwidth of the system 24730. 24731. The resonant frequency of a cavity may be varied by changing any of these parameters except: cavity volume cavity inductance cavity capacitance cavity resistance 24732. 24733. In order to couple two generators to a waveguide system without coupling them to each other, which could not be use? rat-race E-plane T hybrid ring magic T 24734. 24735. A type of tee so-named because of the side arms shunting the E field for the TE modes, which is analogous to voltage in the transmission lines magic tee rat tee series tee shunt tee 24736. 24737. Which one of the following waveguide tuning components is not easily adjustable? screw stub iris plunger 24738. 24739. What type of waveguide is widely used? circular ridged flexible rectangular 24740. 24741. A piston attenuator is a vane attenuator waveguide below cutoff mode filter flap attenuator 24742. 24743. Waveguides act as _____. low-pass filter bandpass filter high-pass filter band-stop filter 24744. 24745. Cylindrical cavity resonators are not used with klystron because they have a Q that is too low a shape whose resonant frequency is too difficult to calculate harmonically related resonant frequencies too heavy losses 24746. 24747. In waveguides, if no component of the E field is in the direction of propagation the mode is said to be TE TM TEM TME 24748. 24749. A directional coupler with three or more holes is sometimes used in preference to the two-hole coupler because it is more efficient to increase coupling of the signal to reduce spurious mode generation to increase the bandwidth of the system 24750. 24751. 24752. 24753. The smallest free-space wavelength that is just unable to propagate in the waveguide cutoff wavelength cutoff frequency cutoff waveguide length cutoff phase 24754. 24755. It is the minimum frequency of waves that can propagate through the waveguide cutoff frequency cutoff wavelength cutoff phase cutoff waveguide length 24756. 24757. A common application of magnetrons is in Radar Satellites Two-way radio TV sets 24758. 24759. In waveguides, it is the velocity at which the wave changes phase waveguide velocity group velocity phase velocity total velocity 24760. 24761. The maximum power that may be handled by a ferrite component is limited by the curie temperature saturation magnetization line width gyromagnetic resonance 24762. 24763. In waveguides, it is the velocity at which the wave propagates phase velocity group velocity total velocity waveguide velocity 24764. 24765. 24766. 24767. 24768. 24769. A PIN diode is a metal semiconductor point-contact diode a microwave mixer diode often used as a microwave detector suitable for use as a microwave switch 24770. 24771. A common omnidirectional microwave antenna is the horn parabolic reflector helical bicone 24772. 24773. The output of a helical antenna is vertically polarized horizontally polarized circularly polarized linearly polarized 24774. 24775. For some applications, circular waveguides may be preferred to rectangular ones because of the smaller the cross section needed at any frequency lower attenuation freedom from spurious modes rotation of polarization 24776. 24777. A helical antenna is made up of a coil and a director reflector dipole horn 24778. 24779. In a klystron amplifier, velocity modulation of the electron beam is produced by the collector catcher cavity cathode buncher cavity 24780. 24781. 24782. 24783. 24784. Increasing the diameter of a parabolic reflector causes which of the following: decreased beamwidth increased gain none of the above decreased beamwidth and increased gain 24785. 24786. For low attenuation, the best transmission medium is flexible waveguide ridged waveguide rectangular waveguide coaxial line 24787. 24788. Low-power Gunn diodes are replacing Reflex klystron TWTs Magnetrons Varactor diodes 24789. 24790. One of the reasons why vacuum tubes eventually fail at microwave frequencies is that their noise figure increases transmit time becomes too short shunt capacitive reactances becomes too large series inductance reactances becomes too small 24791. 24792. A rectangular waveguide has a width of 1 inch and a height of 0.6 inch. Its cutoff frequency is 2.54 GHz 3.0 GHz 5.9 GHz 11.8 GHz 24793. 24794. The TWT is sometimes preferred to the multicavity klystron amplifier, because the former is more efficient has a greater bandwidth has a higher number of modes produces higher output power 24795. 24796. The most common cross section of a waveguide is a square circle triangle rectangle 24797. 24798. The cavity magnetron uses strapping to prevent mode jumping prevent cathode back-heating ensure bunching improve the phase-focusing effect 24799. 24800. Signal propagation in a waveguide is by electrons electric and magnetic fields holes air pressure 24801. 24802. The dominant mode in most waveguides is TE 0,1 TE 1,2 TM 0,1 TM 1,1 24803. 24804. Periodic permanent-magnet focusing is used with TWTs to allow pulsed operation improve electron bunching avoid the bulk of electromagnet allow coupled-cavity operation at the highest frequencies 24805. 24806. A popular microwave mixer diode is the Gunn Varactor Hot carrier IMPATT 24807. 24808. 24809. 24810. 24811. A magnetron whose oscillating frequency is electronically adjustable over a wide range is called a coaxial magnetron dither-tune magnetron frequency-agile magnetron VTM 24812. 24813. The main benefit of using microwave is lower-cost equipment sampler equipment greater transmission distances more spectrum space for signals 24814. 24815. Which diode is a popular microwave oscillator? IMPATT Gunn Varactor Schottly 24816. 24817. Which of the following is not a disadvantage of microwave? higher cost equipment line-of-sight transmission conventional components are not usable circuits are more difficult ro analyze 24818. 24819. Which of the following is a microwave frequency? 1.7 MHz 750 MHz 0.98 MHz 22 GHz 24820. 24821. In a TWT, the electron beam, is density-modulated by a Permanent magnet Modulation transformer Helix Cavity resonator 24822. 24823. 24824. 24825. 24826. Which of the following is not a common microwave application? radar mobile radio telephone spacecraft communications 24827. 24828. Indicate the false statement. Transit time in microwave tubes will be reduced if the electrodes are brought closer together a higher node current is used multiple or coaxial loads are used the anode voltage is made larger 24829. 24830. Coaxial cable is not widely used for long microwave transmission lines because of its high loss high lost large size excessive radiation 24831. 24832. The main advantage of the TWT over a klystron for microwave amplification is lower cost smaller size higher power wider bandwidth 24833. 24834. A magnetic field is used in the cavity magnetron to prevent anode current in the absence of oscillations ensure that the oscillations are pulsed help in focusing the electron beam, thus preventing spreading ensure that the electrons will orbit around the cathode 24835. 24836. A waveguide has a cutoff frequency of 17 GHz. Which of the signals will not be passed by the waveguide? 15 GHz 18 GHz 22 GHz 25 GHz 24837. 24838. 24839. 24840. When the electric field in a waveguide is perpendicular to the direction of wave propagation, the mode is said to be vertical polarization transverse electric horizontal polarization transverse magnetic 24841. 24842. The TWT is sometimes preferred to the magnetron as a radar transmitter output tube because it is capable of longer duty cycle a more efficient amplifier more broadband less noisy 24843. 24844. A magnetic field is introduced into a waveguide by a probe dipole stripline capacitor 24845. 24846. A reflex klystron is used as a/n amplifier oscillator mixer frequency multiplier 24847. 24848. Indicate the false statement: Manganese ferrite may be used as a circulator isolator garnet phase shifter 24849. 24850. Indicate the false statement. Klystron amplifiers may use intermediate cavities to prevent oscillations that occur in two-cavity klystron increase the bandwidth of the device improve the power gain increase the efficiency of the klystron 24851. 24852. 24853. What are limits of microwaves? 1 – 25,000 GHz 1 – 50,000 GHz 1 – 75,000 GHz 1 – 100,000 GHz 24854. 24855. The following transmission lines are used for microwave frequencies, except: waveguide twin lead coax stripline 24856. 24857. How much must a waveguide be? over a half-wave over a quarterwave over a wavelength over three-fourths of a wavelength 24858. 24859. How high must a waveguide be? over a wavelength over a quarter wave over a half wave over two wavelengths 24860. 24861. What is the designation of the lowest-frequency microwave band? V band X band Ku band L band 24862. 24863. What is the designation of the highest-frequency microwave band? R band Ka band V band L band 24864. 24865. 24866. 24867. 24868. 24869. What is reduced by using choke flanges? refraction reflection absorption cancellation 24870. 24871. What is the name of the microwave transmission line that is used in printed circuits? microstrip coax twin lead twisted pair 24872. 24873. Where is the resistive load placed in a directional coupler? front end of the primary front end of the secondary back end of the primary back end of the secondary 24874. 24875. One of the following is a type of bolometer calorimeter thermocouple barreter carreter 24876. 24877. Why are bolometers not used to detect modulation? thermal sluggishness inefficiency less accurate less precise 24878. 24879. The advantage of a resonant cavity over a hairpin tank? lesser Q wider bandwidth higher Q efficiency 24880. 24881. 24882. 24883. 24884. 24885. What type of coupling is used between a waveguide and a waveguide wavemeter? loop antenna quarterwave antenna hole E probe 24886. 24887. Which microwave tube has a repeller? TWT Klystron Magnetron BWO 24888. 24889. Which microwave tube has a series of cavities? magnetron klystron TWT BWO 24890. 24891. Which microwave tube has a helix klystron magnetron multicavity klystron BWO 24892. 24893. Which microwave tube has a horseshoe magnet? magnetron klystron TWT BWA 24894. 24895. What is the advantage of a gridless klystron power input gain attenuator power output 24896. 24897. 24898. 24899. 24900. 24901. Which vacuum tube do you think oscillate at the highest frequency Magnetron Gunn Klystron BWO 24902. 24903. How would a balun be used to change 200 ohms to 50 ohms? use a higher turns ratio use a higher frequency reverse it use low frequency 24904. 24905. How could a balun change 100 ohms to 900 ohms use 3:1 turns ratio use 1:3 turns ratio use 9:1 turns ratio use 1:9 turns ratio 24906. 24907. How high a frequency can transistor generate? above 10 GHz above 5 GHz above 2 GHz above 7.8 GHz 24908. 24909. What is the microwave application of a varactor? mixer frequency multiplier demodulator demultiplexer 24910. 24911. What diode does better than varactor in microwave frequencies? step recovery tunnel PIN Gunn 24912. 24913. 24914. 24915. 24916. 24917. The following diodes can generate microwave AC except: Tunnel LSA IMPATT Magnetron 24918. 24919. For what are PIN diodes used in microwave? mixers modulators oscillators amplifier 24920. 24921. What is the other name for LSA diodes? negative resistance bulk-effect tunneling effect time-space 24922. 24923. What is the advantage of LSA over a Gunn Diode? more efficient higher power less noise higher frequency 24924. 24925. What is wrong with the term Gunn Diode? not a gun not a semiconductor not a diode should be spelled with single “n” 24926. 24927. What is important property do ferrites have which is used as a switch? faraday rotation resonance absorption magnetic properties high curie temperature 24928. 24929. 24930. 24931. 24932. 24933. Which is used in circulators? resonance absorption magnetic properties ion resonance faraday rotation 24934. 24935. What is the advantage of using a circulator with two transmitter and two receivers? many antennas less interference easy coupling one antenna only 24936. 24937. To what must the fourth port be connected in a tunnel diode amplifier? resistor inductor capacitor impedance 24938. 24939. To what must the third port be connected in a multiplexer circulator reflecting short circuit absorbing short circuit reflecting open circuit absorbing open circuit 24940. 24941. What does radar mean? radio detection and range radio direction and radiation radio direction and range range direction radiation 24942. 24943. In what distance unit are marine radars calibrated? statute miles kilometers nautical miles feet 24944. 24945. 24946. 24947. 24948. 24949. What time unit is the equivalent of a radar mile? 12.3 microseconds 6.8 microseconds 4.5 microseconds 7.1 microseconds 24950. 24951. In what frequency band does marine radar operate? 9.5 GHz S band 3 GHz X band 9.5 GHz Ku band 3 GHz S band 24952. 24953. To what two circuits would a radar timer circuit feed signals? modulator and mixer amplifier and circulator modulator and circulator amplifier and modulator 24954. 24955. What is the target display on a CRT called? crosshair blip center spot round 24956. 24957. What is the main bang on a PPI radar set? blip center spot bearing round 24958. 24959. What is the ability to separate adjacent equidistant targets called? bearing resolution narrow bandwidth high frequency shorter wavelength 24960. 24961. 24962. 24963. 24964. 24965. What is the approximate rotational rate of a radar antenna? 20 rpm 5 rpm 25 rpm 10 rpm 24966. 24967. How is radar CRTs differ from TV? square round rectangular trapezoidal 24968. 24969. What circuits make up the radar transmitter? multivibrator trapezoidal oscillator sinewave generator blocking oscillator 24970. 24971. What type of oscillator determines the PRR? blocking pulse square blocking or pulse 24972. 24973. What other circuit might be used as an oscillator that determines the PRR? trapezoidal generator unbalanced multivibrator bistablemultivibrator sinewave generator 24974. 24975. Why are hydrogen-gas thyratrons used in radar? fast-ionize cheaper accurate efficient 24976. 24977. 24978. 24979. 24980. 24981. What is the other name for a pulse-forming network in radars? tuned circuit oscillators delay line capacitive circuits 24982. 24983. What determines the PRR in odd-time radar sets? tuned circuit frequency oscillator frequency spark gap speed MOPA transmitter time 24984. 24985. What is used to carry RF energy from magnetron to antenna in a radar set? helix parallel wireline coax waveguide 24986. 24987. What is the method of illuminating a parabolic reflector with RF? horn cassegrain helix coax 24988. 24989. How would a radar reflector be parabolic-shaped circularly vertically horizontally none of these 24990. 24991. In what way are radar emissions similar to microwave ovens? can transmit can receive can cook can transceiver 24992. 24993. 24994. 24995. 24996. 24997. To what tube is a dc keep-alive voltage applied? Oscillator Transmit-Receive Mixer Circulator Isolator 24998. 24999. In radar, if the mixer diode burns out, what are replaced? tube mixer antenna diode 25000. 25001. What is the cavity between magnetron and mixer cavity called? ATR TR Transmit Receive 25002. 25003. Radar receivers use what Ifs 20 MHz and lower 10 MHz and higher 30 MHz or higher 10 MHz and lower 25004. 25005. What kind of local oscillators does a radar receiver use? klystron magnetron LSA TWT 25006. 25007. What solid-state types might be used as a radar receiver? Gunn diode Tunnel diode Hot carrier diode Step recovery diode 25008. 25009. 25010. 25011. 25012. 25013. What does an ATR tube aid? transmitting receiving both transmitting and receiving neither transmitting and receiving 25014. 25015. To what is the AFC voltage applied in a klystron? cathode grid plate any of these 25016. 25017. Sea return is the control that desentisizes a radar receiver for _____ 5 – 10 microseconds 15 – 20 microseconds 10 – 15 microseconds 20 – 25 microseconds 25018. 25019. In radars, how is blooming prevented? limit modulation video signal limit the carrier signal limit the audio signal 25020. 25021. How is brilliance controlled in radars? audio gain IF gain RF gain video gain 25022. 25023. How is sensitivity limited in radars? RF gain video gain audio gain IF gain 25024. 25025. 25026. 25027. 25028. 25029. How much intensifying pulse is used in radars? Just enough to produce light flicker on screen should be high to produce light flicker on screen should be low to produce light flicker on screen any amount of intensifying pulse will do 25030. 25031. If echo signals are developed as negative pulses, to what part of the CRT would they be fed in radar? anode grid cathode 2nd grid 25032. 25033. What starts the range-marker circuit ringing in radars? intensifying pulse IF gain AC signal Carrier signal 25034. 25035. Why is a selsyn pair not too successful for radar antenna synchronization? constant lead angle variable lag angle constant lag angle variable lead angle 25036. 25037. What is fed to the rotor of a selsyn motor? power-line AC DC source A pulsating DC None 25038. 25039. What is fed to the rotor selsyn generator? none power-line AC DC source A pulsating DC 25040. 25041. 25042. 25043. What is fed to a control transformer rotor? A pulsating DC power-line AC DC source none 25044. 25045. What is used to indicate the bow of the ship on the CRT? tail flash body flash heading flash none 25046. 25047. When is an echo box used on ships? testing only direction finding auto alarm ship detection 25048. 25049. What qualification must a person have before he is eligible to make repairs to a radar set? NTC endorsement repair license repair endorsement radar endorsement 25050. 25051. What is the advantage of using Doppler radar? shows only moving target shows stationary target shows both moving and stationary target produce blips with stationary targets 25052. 25053. How would Doppler radar give speed indications? adjust output burst correct RF carrier output switch amplitude detector calibrate discriminator output 25054. 25055. 25056. 25057. 25058. 25059. What is another application of Doppler radar? distance between radar and stationary target ground speed indicator ground missile indicator enemy base station 25060. 25061. Why are signal nulls used in Radio Direction Finders work? sharper than maximums sharper than minimums duller than maximums duller than minimums 25062. 25063. How many are signal nulls in one loop rotation Radio Direction Finders? 3 4 5 2 25064. 25065. Under what conditions do the horizontal portions of a loop pick up difference currents in RDF? ground waves sky waves space waves direct waves 25066. 25067. The method of balancing a loop used in RDF? Capacitor to ground Capacitor to sense antenna Sense antenna to one side of loop Any of these 25068. 25069. For what are unidirectional readings used in loops for RDF? resolve a 180 degrees ambiguity resolve a 90 degrees ambiguity resolve a 360 degrees ambiguity resolve a 270 degrees ambiguity 25070. 25071. 25072. 25073. 25074. What kind of antenna is a sense antenna used in RDF? circular vertical horizontal any of these 25075. 25076. In RDF, what happens to a radio wave path as it moves outward across a coastline as less than 90 degrees? bends away from the shore travels along the shore bends towards shore travels across the shore 25077. 25078. What is the result of antenna effect in RDF? rotated 90 degrees nulls shift decreases land effect coastline refraction 25079. 25080. What is the result of re-radiation of signals in RDF? great circle error non-opposite minimums polarization errors nulls shifted 25081. 25082. What causes night effect in direction finding? ground plus space wave sky plus space wave ground plus sky waves ground wave alone 25083. 25084. At what time of the day is direction finder bearings least accurate sunset sunrise mid-day sunset and sunrise 25085. 25086. 25087. 25088. 25089. At what angles are quadrantal errors maximum in direction finding 45 degrees 90 degrees 180 degrees 270 degrees 25090. 25091. How are quadrantal errors corrected? 330 degrees 360 degrees 315 degrees 215 degrees 25092. 25093. How is it that none of the 120-550 kHz ADF circuits are tuned to the desired station? narrowband amplifiers broadband amplifiers IF amplifiers Mixers 25094. 25095. What is the only hand-tuned circuit in the ADF? 3125-kHz signal local oscillator 4125-kHz signal local oscillator 2182-kHz signal local oscillator 2230-kHz signal local oscillator 25096. 25097. What forms the error signal that actuates the ADF servo-motor? 75-Hz carrier 114-Hz carrier 114-Hz sideband 75-Hz sideband 25098. 25099. Which ADF antenna is used for manual operation? parabolic antenna loop antenna half-wave dipole helical antenna 25100. 25101. 25102. 25103. 25104. 25105. Which ADF antenna is used for simple receive operation? loop antenna sense antenna quarterwave antenna parabolic antenna 25106. 25107. What is heard by earphones in the ADF? 3 kHz beat 1 kHz beat 2 kHz beat 5 kHz beat 25108. 25109. If two bearing are determined from a radio beacon or station over a period of a few minutes, what else must be known to determine the ship’s position? speed elapses time ship’s course any of these 25110. 25111. What important point regarding-loop RDF system maintenance? insulation at top of loop clean moving contacts oil bearing of loop any of these 25112.

25113. 25114. 25115. 25116. 25117. 25118. 25119. 25120. 25121. 25122. 25123. 25124. MULTIPLE CHOICE QUESTIONS IN 25125. TELEPHONY AND FACSIMILE 25126. Electronics Systems and Technologies 25127. By 25128. Melvin C. Arceo 25129. 25130. 25131. 25132. 25133. 25134. 25135. 25136. 25137. ENCODED BY: 25138. RIVERA, Billy Joe S.

25139. 1. The simplest and most straightforward form of telephone service is called 25140. 25141. Public switch telephone network 25142. Mobile telephone switching office 25143. Plain and old telephone service 25144. Central office service 25145. 25146. 2. ______are local telephone switches equipped with SS7-compatible software and terminating signal links 25147. 25148. A. switching points 25149. B. service points 25150. C. point codes 25151. D. service switching points 25152. 25153. 3. A PABX is normally connected to the central office via an interface device called 25154. 25155. A. branch exchange unit 25156. B. subscriber loop unit 25157. C. foreign exchange unit 25158. D. local exchange unit 25159. 25160. 4. The most widely used fax standard is 25161. 25162. A. group 1 25163. B. group 2 25164. C. group 3 25165. D. group 4 25166. 25167. 5. The modern Touch-tone telephone is called 25168. 25169. A. 600-type telephone set 25170. B. 2500-type telephone set 25171. C. 2800-type telephone set 25172. D. 1500-type telephone set 25173. 25174. 6. Signals that provides call status information, such as busy or ringback signals 25175. 25176. A. supervising 25177. B. hybriding 25178. C. controlling 25179. D. ringing 25180. 25181. 7. A signal sent back to the calling party at the same time the ringing signal is sent to the called party 25182. 25183. A. busy signal 25184. B. ringing signal 25185. C. ringback signal 25186. D. dial tone 25187. 25188. 8. It is comprised of two or more facilities, interconnected in tandem, to provide a transmission path between a source and a destination 25189. 25190. A. telephone line 25191. B. telephone set 25192. C. telephone circuit 25193. D. telephone trunk 25194. 25195. 9. The drum diameter of a facsimile machine is 90.2 mm and the scanning pitch is 0.2 mm per scan. Find the index of cooperation according to CCITT 25196. 25197. A. 451 25198. B. 2.22 x 10^-3 25199. C. 1417 25200. D. 144 25201. 25202. 10. It is the ratio in dB of the power of a signal at that point to the power the same signal would be 0-dBm at any point in the transmission system 25203. 25204. A. data level 25205. B. baseband level 25206. C. voice level 25207. D. transmission level 25208. 25209. 11. It is an indirect method of evaluating the phase delay characteristics of the circuit 25210. 25211. A. phase delay distortion 25212. B. envelope delay distortion 25213. C. non-linear distortion 25214. D. linear distortion 25215. 25216. 12. It is characterized by high-amplitude peaks of short duration having an approximately flat frequency response 25217. 25218. A. crosstalk 25219. B. interference 25220. C. impulse noise 25221. D. drop out 25222. 25223. 13. It is the presence of one or more continuous, unwanted tones within the message channels, the tones are often caused by crosstalk or cross modulation between adjacent channels in a transmission system due to system nonlinearities. 25224. 25225. A. multiple-frequency interference 25226. B. single-frequency interference 25227. C. co-channel interference 25228. D. desensitizing 25229. 25230. 14. That portion of the local loop that is strung between the poles 25231. 25232. A. aerial 25233. B. distribution cable 25234. C. feeder cable 25235. D. twisted-pair 25236. 25237. 15. It is the primary cause of attenuation and phase distortion on a telephone circuit 25238. 25239. A. local line 25240. B. local loop 25241. C. subscriber loop 25242. D. any of these 25243. 25244. 16. It is simply the frequency response of a transmission medium referenced to a 1004-Hz test tone 25245. 25246. A. attenuation distortion 25247. B. differential gain 25248. C. 1004-Hz deviation 25249. D. any of these 25250. 25251. 17. The time delay measured in angular units, such as degrees or radians is called ______25252. 25253. A. propagation time 25254. B. phase delay 25255. C. holding time 25256. D. system delay time 25257. 25258. 18. It is a communications term that indicates the presence of a signal power comparable to the power of an actual message transmission 25259. 25260. A. dynamic range 25261. B. loaded 25262. C. node 25263. D. reference 25264. 25265. 19. It is any device used to originate and terminate calls and to transmit and receive signals into and out of the telephone network 25266. 25267. A. instrument 25268. B. station equipment 25269. C. station 25270. D. any of these 25271. 25272. 20. Exchanges connected directly to the local loops are called ______25273. 25274. A. central office 25275. B. local exchange 25276. C. exchange offices 25277. D. any of these 25278. 25279. 21. It provides functionality of communicating with the voice switch by creating the packets or signal units necessary for transmission over the SS7 network 25280. 25281. A. switching points 25282. B. service points 25283. C. point codes 25284. D. service switching points 25285. 25286. 22. In a 4-wire telephone set connection, (used to connect telephone set to central office switching) the green coded wire is used ______25287. 25288. A. as ground wire 25289. B. to transmit the signal 25290. C. to receive the signal from the far end 25291. D. as a spare or for special purpose applications 25292. 25293. 23. A technique where the called subscriber is served by any other central office, the switching equipment will have to transfer the digit dialed to the called switching equipment. 25294. 25295. A. loop signaling 25296. B. step-by-step switching 25297. C. interoffice calling 25298. D. duplex signaling 25299. 25300. 24. Electromagnetic coupling between two or more physically interconnected transmission media is what type of crosstalk? 25301. 25302. A. coupling crosstalk 25303. B. transmission crosstalk 25304. C. linear crosstalk 25305. D. non-linear crosstalk 25306. 25. The number of dedicated lines used to interconnect 100 parties 25307. 25308. A. 99 lines 25309. B. 1250 lines 25310. C. 4950 lines 25311. D. 3450 lines 25312. 25313. 26. Class of switching office which is the local exchange where the subscriber loops terminated and received dial tone. 25314. 25315. A. Class 5 25316. B. Class 4C 25317. C. Class 3 25318. D. Class 1 25319. 25320. 27. The maximum intelligibility of voice frequency is between 25321. 25322. A. 2000 and 3000 Hz 25323. B. 1000 and 3000 Hz 25324. C. 2500 and 4000 Hz 25325. D. 1000 and 2500 Hz 25326. 25327. 28. It is the state of the telephone when it is idle. 25328. 25329. A. on-hook 25330. B. off-hook 25331. C. semi-hook 25332. D. hook-in 25333. 25334. 29. Type of loop signaling which is widely used in new switching systems to supervise trunks between two central offices. 25335. 25336. A. battery and ground pulsing 25337. B. reverse battery signaling 25338. C. loop pulsing 25339. D. duplex signaling 25340. 25341. 30. Printed documents to be transmitted by fax are converted into a baseband electrical signal by the process of 25342. 25343. A. reflection 25344. B. scanning 25345. C. modulation 25346. D. light variations 25347. 25348. 31. The transmission speed of group 4 fax is 25349. A. 4800 baud 25350. B. 9600 baud 25351. C. 56 kbps 25352. D. 192 kbps 25353. 25354. 32. It is a distortion formed if SSB is used where the information bandwidth is greater than half of the carrier frequency. 25355. 25356. A. near-far effect 25357. B. hauffman effect 25358. C. kendall effect 25359. D. herringbone effect 25360. 25361. 33. It is simply an unshielded twisted pair transmission line consisting of two insulated conductors twisted together. 25362. 25363. A. local loop 25364. B. local line 25365. C. subscriber loop 25366. D. any of these 25367. 25368. 34. It is an audible signal comprised of two frequencies: 350 Hz and 440 Hz 25369. 25370. A. dial tone 25371. B. ringback signal 25372. C. busy tone 25373. D. call waiting tone 25374. 25375. 35. It enables the destination station of a telephone call to display the name of the telephone number of the calling party before the telephone is answered. 25376. 25377. A. conference call 25378. B. call wait 25379. C. call forwarding 25380. D. caller id 25381. 25382. 36. The largest cable used in a local loop, usually 3600 pair of copper wires placed underground or in conduit. 25383. 25384. A. feeder cable 25385. B. distribution cable 25386. C. drop wire 25387. D. drop-wire cross-connect cables 25388. 25389. 37. A weighting technique that assumes a perfect receiver only, therefore its weighting curve corresponds to the frequency response of the ear only. 25390. A. relative noise weighting 25391. B. above relative noise weighting 25392. C. C-message noise weighting 25393. D. psophometric noise weighting 25394. 25395. 38. The difference between the absolute delays of all frequencies. 25396. 25397. A. relative phase delay 25398. B. phase delay distortion 25399. C. absolute phase delay 25400. D. phase distortion 25401. 25402. 39. A special type of line conditioning that sets the minimum requirements for signal-to-noise ratio a nonlinear distortion. 25403. 25404. A. A-type line conditioning 25405. B. B-type line conditioning 25406. C. C-type line conditioning 25407. D. D-type line conditioning 25408. 25409. 40. It is a form of incidental phase modulation – a continuous uncontrolled variations in the zero crossings of a signal. 25410. 25411. A. crosstalk 25412. B. co-channel interference 25413. C. phase jitter 25414. D. spikes 25415. 25416. 41. A type of crosstalk which is a direct result of nonlinear amplification in analog communications system 25417. 25418. A. linear crosstalk 25419. B. transmittance crosstalk 25420. C. nonlinear crosstalk 25421. D. coupling crosstalk 25422. 25423. 42. The operator of the telephone instrument 25424. 25425. A. subscriber 25426. B. destination 25427. C. source 25428. D. terminal 25429. 25430. 43. It is a system of sensors, switches and other electronic and electrical devices that allow subscriber to give instructions directly to the switch without having to go through the operator. 25431. 25432. A. manual switching system 25433. B. automated switching system 25434. C. common switching system 25435. D. crossbar switching system 25436. 25437. 44. Toll offices are connected to other toll offices with ______25438. 25439. A. intertoll trunks 25440. B. intratoll trunks 25441. C. interoffice trunks 25442. D. intraoffice trunks 25443. 25444. 45. The highest ranking office in the DDD network in term of size of the geographical area served and the trunk options available. 25445. 25446. A. End office 25447. B. Sectional center 25448. C. Regional center 25449. D. Toll center 25450. 25451. 46. He invented the automatic line selector, which led to the automatic telephone system. 25452. 25453. A. Alexander Bain 25454. B. Alexander Graham Bell 25455. C. Thomas Edison 25456. D. Almon Strowger 25457. 25458. 47. It allows customers to change to a different service and still keep the same phone number 25459. 25460. A. changing 25461. B. porting 25462. C. transporting 25463. D. portability 25464. 25465. 48. By definition, speech power is equal to v.u. reading minus ______25466. 25467. A. 1.8 dB 25468. B. 4 dB 25469. C. 1.4 dB 25470. D. 3 dB 25471. 25472. 49. When the telephone set is in the ______state, a direct current from the central office (CO) flows through the transmitter and receiver of the handset. 25473. 25474. A. on-hook 25475. B. off-hook 25476. C. semi-hook 25477. D. hook-in 25478. 25479. 50. Type of loop signaling which involves opening and closing the loop to dial to or through the central office. 25480. 25481. A. ear and mouth 25482. B. duplex 25483. C. loop pulsing 25484. D. interoffice calling 25485. 25486. 51. When the image at the receiving end of a facsimile transmission is elongated vertically, 25487. 25488. A. the transmitter IOC is less than the receiver IOC 25489. B. the transmitter IOC is greater than the receiver IOC 25490. C. the transmitter IOC is equal to the receiver IOC 25491. D. the IOC is not a factor 25492. 25493. 52. In FM fax, the frequencies for black and white are 25494. 25495. A. 1500 and 2300 Hz 25496. B. 2200 and 1500 Hz 25497. C. 1300 and 2400 Hz 25498. D. 1070 and 1270 Hz 25499. 25500. 53. It is a measure of the faithful reproduction of scanned prints in a facsimile communications. 25501. 25502. A. fidelity 25503. B. contrast 25504. C. legibility 25505. D. chroma 25506. 25507. 54. The feedback signals that help prevent the speaker from talking too loudly. 25508. 25509. A. busy tone 25510. B. ringback tone 25511. C. dial tone 25512. D. sidetone 25513. 25514. 55. It is the exchange of signaling messages between switching machines 25515. 25516. A. loop signaling 25517. B. station signaling 25518. C. interoffice signaling 25519. D. pulse signaling 25520. 25521. 56. A signal sent from the switching machine back to the calling station whenever the system cannot complete call because of equipment unavailability. 25522. 25523. A. busy tone 25524. B. call waiting tone 25525. C. fax tone 25526. D. congestion tone 25527. 25528. 57. The final length of cable pair that terminates at the SNI 25529. 25530. A. aerial 25531. B. drop wire 25532. C. distribution cable 25533. D. cross-connect cables 25534. 25535. 58. It is the difference in circuit gain experienced at a particular frequency with respect to the circuit gain of a reference frequency. 25536. 25537. A. dynamic range 25538. B. absorption distortion 25539. C. attenuation distortion 25540. D. selective fading 25541. 25542. 59. In telephone systems, a special type of line conditioning that pertains to line impairments for which compensation can be made with filters and equalizers. 25543. 25544. A. A-line conditioning 25545. B. B-line conditioning 25546. C. C-line conditioning 25547. D. D-line conditioning 25548. 25549. 60. An envelope delay distortion test on a basic telephone channel indicated that an 1800-Hz carrier experienced the minimum absolute delay of 400 us. The maximum envelope delay for a basic telephone channel is 1750 us within the frequency range 800 Hz to 2600 Hz. What is the maximum envelope delay? 25550. 25551. A. 2150 microsec 25552. B. 2550 microsec 25553. C. 3000 microsec 25554. D. 3400 microsec 25555. 25556. 61. In SS7 signaling points, codes that are carried in signaling messages exchanged between signaling points to identify the source and destination of each message 25557. 25558. A. signaling points 25559. B. service points 25560. C. switching points 25561. D. point codes 25562. 25563. 62. Stage of the step-by-step switching system that is composed of switches to complete the connection to the called subscriber. 25564. 25565. A. line equipment 25566. B. switch train 25567. C. connectors 25568. D. switching network 25569. 25570. 63. ______is the switching system that is a branch of the local central office. 25571. 25572. A. local exchange 25573. B. branch exchange 25574. C. subscriber loop 25575. D. line 25576. 25577. 64. Most fax printers are of which type? 25578. 25579. A. Impact 25580. B. Thermal 25581. C. Electrosensitive 25582. D. Laser xerographic 25583. 25584. 65. Aside from tip and ring used in local loops the third wire when used is called ______. 25585. 25586. A. reserve 25587. B. sleeve 25588. C. ground 25589. D. none of these 25590. 25591. 66. Acknowledgement and status signals that ensure the process necessary to set up and terminate a telephone call are completed in an orderly and timely manner, 25592. 25593. A. call progress tones and signals 25594. B. call waiting tones and signals 25595. C. incoming call tones and signals 25596. D. call termination tones and signals 25597. 25598. 67. POCSAG stands for 25599. 25600. A. Post Office Code Standardization Advisory Group 25601. B. Post Office Code System Advisory Group 25602. C. Paging Operation Code Standardization Advisory Group 25603. D. Paging Operation Code System Advisory Group 25604. 68. The location where individual cable pairs within a distribution cable are separated and extended to the subscriber’s location on a drop wire 25605. 25606. A. feeder cable and distribution cable 25607. B. drop wire and aerial cable 25608. C. distribution cable and drop-wire cross-connect cables 25609. D. distribution cable and aerial cable 25610. 25611. 69. In telephone systems, a special type of line conditioning that specifies the maximum limit for attenuation distortion and envelope delay distortion. 25612. 25613. A. A-line conditioning 25614. B. B-line conditioning 25615. C. C-line conditioning 25616. D. D-line conditioning 25617. 25618. 70. A the receiver, the phase difference at the different carrier frequencies is called ______. 25619. 25620. A. envelope delay distortion 25621. B. phase delay 25622. C. envelope delay 25623. D. propagation time 25624. 25625. 71. It is a sudden, random changes in the phase of the signal. They are classified as temporary variations in the phase of the signal lasting longer than 4 ms. 25626. 25627. A. phase hits 25628. B. phase jitter 25629. C. interference 25630. D. distortion 25631. 25632. 72. Circuits that are designed and configured for their use only and often referred to as private circuits or dedicated circuits. 25633. 25634. A. switched circuits 25635. B. leased circuits 25636. C. virtual circuits 25637. D. switched virtual circuits 25638. 25639. 73. It is a programmable matrix that allows circuits to be connected to one another. 25640. 25641. A. circuit switch 25642. B. tap switch 25643. C. equipment switch 25644. D. cross switch 25645. 25646. 74. Interstate long distance telephone calls require a small telephone office called ______. 25647. 25648. A. sectional office 25649. B. regional office 25650. C. toll office 25651. D. end office 25652. 25653. 75. A call that cannot be completed because the necessary trunk circuits or switching paths are not available. 25654. 25655. A. blocking 25656. B. holding 25657. C. storing 25658. D. none of these 25659. 25660. 76. A mandate that requires all telephone companies to support the porting of telephone number. 25661. 25662. A. national number portability 25663. B. regional number portability 25664. C. local number portability 25665. D. sectional number portability 25666. 25667. 77. The connection between the telephone and the central office’s switching equipment. 25668. 25669. A. subscriber loop 25670. B. relay circuits 25671. C. line sensors 25672. D. supervisory relay 25673. 25674. 78. An exact reproduction of a document or picture provided at the receiving end. 25675. 25676. A. television 25677. B. telecommunication 25678. C. facsimile transmission 25679. D. mobile communication 25680. 25681. 79. What type of graphics are commonly transmitted by radio fax? 25682. 25683. A. Newspaper text 25684. B. Architectural drawings 25685. C. Cable movies 25686. D. Satellite weather photos 25687. 25688. 80. It is comprised of a transmitter, receiver, an electrical network for equalization, associated circuitry to control sidetone levels and to regulate signal power and necessary signaling circuitry. 25689. 25690. A. telephone 25691. B. television 25692. C. facsimile 25693. D. computer 25694. 25695. 81. Early paging system uses what modulation technique? 25696. 25697. A. pulse modulation 25698. B. amplitude modulation 25699. C. phase modulation 25700. D. frequency modulation 25701. 25702. 82. A device that serves as a demarcation point between local telephone company responsibility and subscriber responsibility for telephone service. 25703. 25704. A. standard network interface 25705. B. subscriber line interface card 25706. C. system network architecture 25707. D. network interface card 25708. 25709. 83. It is the actual time required for a particular frequency to propagate from a source to a destination through a communications channel. 25710. 25711. A. relative phase delay 25712. B. phase delay distortion 25713. C. absolute phase delay 25714. D. phase distortion 25715. 25716. 84. It is a sudden, random change in the gain of the circuit resulting in a temporary change in the signal level. 25717. 25718. A. spikes 25719. B. gain hits 25720. C. jitter 25721. D. echo 25722. 25723. 85. A typical echo suppressor suppresses the returned echo by how much? 25724. 25725. A. 10 dB 25726. B. 30 dB 25727. C. 45 dB 25728. D. 60 dB 25729. 25730. 86. In telephony, functions that supply and interpret control and supervisory signals needed to perform the operation 25731. 25732. A. calling functions 25733. B. maintenance functions 25734. C. signaling functions 25735. D. transmission functions 25736. 25737. 87. It is a central location where subscribers are interconnected, either temporarily or on a permanent basis. 25738. 25739. A. central offices 25740. B. exchange offices 25741. C. exchanges 25742. D. any of these 25743. 25744. 88. It is simply a path between two subscribers and is comprised of one or more switches, two local loops or possibly one or more trunk circuits. 25745. 25746. A. way 25747. B. route 25748. C. path 25749. D. mode 25750. 25751. 89. It defines the procedures and protocols necessary to exchange information over the PSTN using a separate digital signaling network to provide wireless and wireline telephone call setup, routing and control. 25752. 25753. A. any of these 25754. B. common channel signaling system no. 7 25755. C. SS7 25756. D. C7 25757. 90. In a 4-wire telephone set connection, (used to connect telephone set to central office switching) the red coded wire is used ______. 25758. 25759. A. as ground wire 25760. B. to transmit the signal 25761. C. to receive the signal from the far end 25762. D. as a spare or for special purpose applications 25763. 25764. 91. The connection between two central offices 25765. 25766. A. line 25767. B. trunk 25768. C. loop 25769. D. signaling 25770. 25771. 92. In facsimile, the length of time required to transmit a document 25772. A. propagation time 25773. B. transmission rate 25774. C. holding time 25775. D. transmission time 25776. 25777. 93. It is a combination of passive components that are used to regulate the amplitude and frequency response of the voice signals. 25778. 25779. A. equalizer circuit 25780. B. balanced transformer 25781. C. balanced modulator 25782. D. hybrid network 25783. 25784. 94. A signal that is sent from the switching machine back to the calling station whenever the called telephone number is off-hook. 25785. 25786. A. dial tone signal 25787. B. ringback signal 25788. C. busy signal 25789. D. off-hook signal 25790. 25791. 95. A smaller version of the feeder cable containing less wire pairs. 25792. 25793. A. aerial 25794. B. drop wire 25795. C. feeder cable 25796. D. distribution cable 25797. 25798. 96. It is a parameter equivalent to TLP except that it is used as a reference for data transmission. 25799. 25800. A. transmission level point 25801. B. data level point 25802. C. voice level point 25803. D. baseband transmission point 25804. 25805. 97. He developed the first instrument that transmitted music over a wire 25806. 25807. A. Philipp Reis 25808. B. Antonio Meucci 25809. C. Thomas Edison 25810. D. Almon Strowger 25811. 25812. 98. It is used to convert two-wire circuits to four-wire circuits which is similar to hybrid coil found in standard telephone sets. 25813. 25814. A. balanced transformer 25815. B. hybrid circuits 25816. C. balanced modulator 25817. D. hybrid transformers 25818. 25819. 99. A switchboard with four digits can accommodate how many telephone numbers? 25820. 25821. A. 1,000 25822. B. 10,000 25823. C. 100,000 25824. D. 9999 25825. 25826. 100. The trunk circuits that are terminated in tandem switches are called 25827. 25828. A. tie trunks 25829. B. tandem trunks 25830. C. office trunks 25831. D. exchange trunks 25832. 25833. 101. The class of switching office that provides service to small groups of class 4 offices within a small area of state. 25834. 25835. A. Class 1 25836. B. Class 4 25837. C. Class 2 25838. D. Class 3 25839. 25840. 102. A device used to measure speech volume 25841. 25842. A. volume unit meter 25843. B. volume milliammeter 25844. C. volume pulse meter 25845. D. volume intensity meter 25846. 25847. 103. The communications between two or three central offices is called 25848. 25849. A. interoffice link 25850. B. trunk 25851. C. interoffice calling 25852. D. loop 25853. 25854. 104. In telephony, the -48V dc voltage was used rather than ac voltages because 25855. 25856. A. to prevent power supply hum 25857. B. to allow service to continue in the event of power outage 25858. C. because people are afraid of ac 25859. D. all of these 25860. 105. Category of signaling message that indicates a request of service, such as going off-hook or ringing in the destination telephone 25861. 25862. A. dial tone 25863. B. signaling 25864. C. supervising 25865. D. alerting 25866. 25867. 106. Occurs in coherent SSBSC systems, such as those using frequency division multiplexing when the received carrier is not reinserted with the exact phase relationship to the received signal as the transmit carrier possessed. 25868. 25869. A. phase delay distortion 25870. B. phase jitter distortion 25871. C. phase intercept distortion 25872. D. all of these 25873. 25874. 107. It is simply the dedicated cable facility used to connect an instrument at a subscriber’s station to the closest telephone office. 25875. 25876. A. subscriber lines 25877. B. local loops 25878. C. subscriber loops 25879. D. any of these 25880. 25881. 108. A telephone call completed within a single local exchange is called 25882. 25883. A. intraoffice call 25884. B. intraexchange call 25885. C. intraswitch call 25886. D. any of these 25887. 25888. 109. Type of Class 4 toll center usually had only outward operator service or perhaps no operator service at all. 25889. 25890. A. Class 2 25891. B. Class 4P 25892. C. Class 1 25893. D. Class 3 25894. 25895. 110. In a 4-wire telephone set connection, (used to connect telephone set to office central switching) the yellow coded wire is used ______. 25896. 25897. A. as ground wire 25898. B. to transmit the signal 25899. C. to receive the signal from the far end 25900. D. as a spare or for special purpose applications 25901. 25902. 111. When the image at the receiving end of a facsimile transmission us elongated horizontally, 25903. 25904. A. the transmitter IOC is less than the receiver IOC 25905. B. the transmitter IOC is greater than the receiver IOC 25906. C. the transmitter IOC is equal to the receiver IOC 25907. D. the IOC is not a factor 25908. 25909. 112. It is a special balanced transformer used to convert a two-wire circuit into a four-wire circuit and vice-versa. 25910. 25911. A. equalizer circuit 25912. B. balanced transformer 25913. C. balanced modulator 25914. D. hybrid network 25915. 25916. 113. It is a method originally used to transfer digits in the telephone set to the local switch. 25917. 25918. A. tone dialing 25919. B. dial pulsing 25920. C. battery and ground pulsing 25921. D. reverse battery pulsing 25922. 25923. 114. It is the time required to propagate a change in an AM envelope through a transmission medium 25924. 25925. A. envelope delay distortion 25926. B. phase delay 25927. C. envelope delay 25928. D. propagation time 25929. 25930. 115. It is the primary source of transmission errors in data circuits 25931. 25932. A. impulse noise 25933. B. crosstalk 25934. C. gain hits 25935. D. interference 25936. 25937. 116. It eliminates the echo by electrically subtracting it from the original signal rather than disabling the amplifier in the return circuit. 25938. 25939. A. echo suppressors 25940. B. echo limiters 25941. C. echo cancellers 25942. D. any of these 25943. 117. In telephony, functions that involve the actual transmission of a subscriber’s messages and any necessary control signals. 25944. 25945. A. transmission functions 25946. B. signaling functions 25947. C. maintenance functions 25948. D. calling functions 25949. 25950. 118. The first computer-controlled central office switching system used in PSTN 25951. 25952. A. No.7 ESS 25953. B. No.2 ESS 25954. C. No.5 ESS 25955. D. No. 1 ESS 25956. 25957. 119. It is an exchange without a local loops connected to it 25958. 25959. A. double office 25960. B. tandem office 25961. C. exchange office 25962. D. local office 25963. 25964. 120. The 5-class switching hierarchy is a ______scheme that establishes an end-to-end route mainly through trial and error. 25965. 25966. A. interleaved switching 25967. B. progressive switching 25968. C. point-to-point switching 25969. D. step-by-step switching 25970. 25971. 121. The frequency range of maximum voice energy is between 25972. 25973. A. 150 and 300 Hz 25974. B. 300 and 3400 Hz 25975. C. 250 and 500 Hz 25976. D. 100 and 300 Hz 25977. 25978. 122. The oldest of the automatic switching system 25979. 25980. A. manual switching 25981. B. step-by-step 25982. C. common control 25983. D. Electronic 25984. 25985. 123. Group 3 fax used which modulation? 25986. 25987. A. QAM 25988. B. FSK 25989. C. Vestigial sideband AM 25990. D. FM 25991. 25992. 124. Signals that provides information in the form of announcements, such as number changed to another number, a number no longer in service, and so on 25993. 25994. A. addressing 25995. B. ringing 25996. C. controlling 25997. D. supervising 25998. 25999. 125. The switch closure in an off-hook condition causes a range of dc current to flow on the loop, what is that range of current? 26000. 26001. A. 23 mA to 50 mA 26002. B. 15 mA to 30 mA 26003. C. 10 mA to 20 mA 26004. D. 20 mA to 80 mA 26005. 26006. 126. These are unused sections of cables that are connected in shunt working cable pair, such as a local loop. They are used for party lines to connect to the same local loop. 26007. 26008. A. cross-connect loop 26009. B. drop wire tap 26010. C. bridge tap 26011. D. wire tap 26012. 26013. 127. The time delay encountered by a signal as it propagates from a source to a destination is called ______. 26014. 26015. A. propagation time 26016. B. phase delay 26017. C. holding time 26018. D. system delay time 26019. 26020. 128. It is the decrease in gain of more than 12 dB lasting longer than 4 ms and is a characteristics of temporary open circuit conditions and are generally caused by deep fades in radio facilities or by switching delays. 26021. 26022. A. echo 26023. B. jitter 26024. C. gain hits 26025. D. dropouts 26026. 26027. 129. It is similar to the local loop except that it is used to interconnect two telephone offices. 26028. 26029. A. trunk lines 26030. B. subscriber loop 26031. C. local lines 26032. D. subscriber lines 26033. 26034. 130. Calls that are placed between two stations that are connected to different local exchanges. 26035. 26036. A. interoffice calls 26037. B. interswitch calls 26038. C. interexchange calls 26039. D. any of these 26040. 26041. 131. ______is defined as a momentary on-hook condition that causes loop making and breaking from the telephone set dialer toward the central office. 26042. 26043. A. dial tone 26044. B. dial pulsing 26045. C. on-hook 26046. D. off-hook 26047. 26048. 132. In facsimile technology, it is a number derived from the width-height ratio. 26049. 26050. A. numerical aperture 26051. B. scanning spot 26052. C. index of cooperation 26053. D. cut-off frequency 26054. 26055. 133. In RJ-11, the RJ stands for 26056. 26057. A. Recommended Jack 26058. B. Released Jack 26059. C. Registered Jack 26060. D. Radio Jack 26061. 26062. 134. A cross-connect point used to distribute the larger feeder cable into smaller distribution cables 26063. 26064. A. SLIC 26065. B. serving area interface 26066. C. LATA 26067. D. cross-connect cabinet 26068. 26069. 135. The process used to improve a basic telephone channel is called 26070. 26071. A. line turnaround 26072. B. line conditioning 26073. C. line sensing 26074. D. line improvement 26075. 26076. 136. In telephony, functions that identify and connect subscribers to a suitable transmission path 26077. 26078. A. transmission functions 26079. B. signaling functions 26080. C. switching functions 26081. D. calling functions 26082. 26083. 137. The telephone switching plan that allows a certain degree of route selection when establishing a phone call. 26084. 26085. A. NPA 26086. B. switching hierarchy 26087. C. toll hierarchy 26088. D. interoffice hierarchy 26089. 26090. 138. It provides access to the SS7 network access to databases used by switches inside and outside of the network, and transfer of SS7 messages to other signaling points within the network. 26091. 26092. A. point codes 26093. B. signaling points 26094. C. service points 26095. D. switching points 26096. 26097. 139. The connection between the subscriber and his own particular central office. 26098. 26099. A. trunk 26100. B. line 26101. C. signaling 26102. D. pulsing 26103. 140. It is a measure of how well we can distinguish closely spaced objects or identify small items on a print. 26104. 26105. A. resolution 26106. B. legibility 26107. C. contrast 26108. D. hue 26109. 26110. 141. It is the exchange of signaling messages over local loops between stations and telephone company switching machines 26111. A. loop signaling 26112. B. station signaling 26113. C. interoffice signaling 26114. D. pulse signaling 26115. 26116. 142. Modern paging system uses what modulation technique? 26117. 26118. A. FSK and QPSK 26119. B. PSK and QAM 26120. C. ASK and FSK 26121. D. FSK and PSK 26122. 26123. 143. The talker hears a returned portion of the signal as an echo, what is the round-trip time of delay for an echo to quite annoying? 26124. 26125. A. 15 msec 26126. B. 25 msec 26127. C. 35 msec 26128. D. 45 msec 26129. 26130. 144. When subscriber initiates a long distance calls, the local exchange connects the caller to the toll office through a facility called ______. 26131. 26132. A. interoffice toll trunk 26133. B. intraoffice toll trunk 26134. C. interoffice exchange trunk 26135. D. intraoffice exchange trunk 26136. 26137. 145. Range of speech power 26138. 26139. A. 100 – 1000 uW 26140. B. 10 – 100 uW 26141. C. 10 – 1000 uW 26142. D. 1000 – 10000 uW 26143. 26144. 146. Which resolution produces the best quality fax? 26145. 26146. A. 96 lpi 26147. B. 150 lpi 26148. C. 200 lpi 26149. D. 400 lpi 26150. 26151. 147. Facsimile standards are set by the 26152. 26153. A. FCC 26154. B. DOD 26155. C. CCITT 26156. D. IEEE 26157. 26158. 148. Telephone set component placed directly across the tip and ring to alert the designation party of an incoming call 26159. 26160. A. transmitter 26161. B. receiver 26162. C. ringer 26163. D. dialer 26164. 26165. 149. The reference frequency of a typical voice-band circuit is typically around ______. 26166. 26167. A. 1500 Hz 26168. B. 1300 Hz 26169. C. 1700 Hz 26170. D. 1800 Hz 26171. 26172. 150. The most versatile and popular crossbar switch was ______. 26173. 26174. A. #4YB 26175. B. 5#YB 26176. C. #5XB 26177. D. #5ZB 26178. 26179. 151. A telephone service that uses a common 800 area code regardless of the location of the destination. 26180. 26181. A. wide area telephone service 26182. B. local area telephone service 26183. C. metropolitan area telephone service 26184. D. personal area telephone service 26185. 26186. 152. A device that combines the transmitter and the receiver to operate over the same wire pair. 26187. 26188. A. balancing network 26189. B. diaphragm 26190. C. hybrid 26191. D. relay 26192. 26193. 153. Group 2 fax that uses fax standard is 26194. 26195. A. SSB 26196. B. FSK 26197. C. Vestigial sideband AM 26198. D. PSK 26199. 154. A signal sent from the central office to a subscriber whenever there is an incoming call 26200. 26201. A. busy signal 26202. B. ringing signal 26203. C. ringback signal 26204. D. dial tone 26205. 26206. 155. It is defined as the optimum level of a test tone on a channel at some point in a communications system. 26207. 26208. A. transmission level point 26209. B. data level point 26210. C. voice level point 26211. D. baseband transmission point 26212. 26213. 156. A type of crosstalk which is caused by inadequate control of the frequency response of the transmission system, poor filter design, or poor filter performance. 26214. 26215. A. single-channel crosstalk 26216. B. transmittance crosstalk 26217. C. linear crosstalk 26218. D. coupling crosstalk 26219. 26220. 157. Class of switching office that could provide service to geographical regions varying in size from part of the state to all of several states, depending on population density. 26221. 26222. A. sectional center 26223. B. end office 26224. C. regional center 26225. D. toll center 26226. 26227. 158. By definition, speech power is equal to v.u. reading minus 1.4 dB plus log of N, where N is 26228. 26229. A. The number of lines used 26230. B. The number of transmitters used 26231. C. The number of persons speaking 26232. D. The number of listeners listening 26233. 26234. 159. The most commonly used light sensor in a modern fax machine is a 26235. 26236. A. Phototube 26237. B. Phototransistor 26238. C. Liquid-crystal display 26239. D. Charged coupled device 26240. 26241. 160. Systems that are simplex wireless communications systems designed to alert subscribers of awaiting messages 26242. 26243. A. paging 26244. B. searching 26245. C. texting 26246. D. calling 26247. 26248. 161. It can be defined as any disturbance created in a communications channel by signals in other communications channel. 26249. 26250. A. crosstalk 26251. B. interference 26252. C. hits 26253. D. jitter 26254. 26255. 162. Type of Class 4 toll center which provides human operators for both outward and inward calling service. 26256. 26257. A. Class 4P 26258. B. Class 5 26259. C. Class 4C 26260. D. Class 1 26261. 26262. 163. A type of signaling was developed as an alternative to loop signaling. 26263. 26264. A. ear and mouth 26265. B. duplex 26266. C. loop pulsing 26267. D. interoffice calling 26268. 26269. 164. Signals that provide the routing information, such as calling and called numbers. 26270. 26271. A. routing 26272. B. calling 26273. C. controlling 26274. D. addressing 26275. 26276. 165. Phase jitters occur at what frequency? 26277. 26278. A. less than 300 Hz 26279. B. more than 300 Hz 26280. C. more than 400 Hz 26281. D. more than 300 Hz but less than 400 Hz 26282. 26283. 166. 10 or more subscribers connected in a central office exchange using same local loop 26284. A. wire tapping 26285. B. party lines 26286. C. eaves dropping lines 26287. D. monitor lines 26288. 26289. 167. He designed and built the first transmitter and receiver for a telephone set. 26290. 26291. A. Alexander Graham Bell 26292. B. Alexander Bain 26293. C. Antonio Meucci 26294. D. Philipp Reis 26295. 26296. 168. If a switching machine is set to accept pulses at a rate of 10 pulses per second with a 60% break, find the make interval of the switch. 26297. 26298. A. 60 ms 26299. B. 100 ms 26300. C. 40 ms 26301. D. 25 ms 26302. 26303. 169. How many point-to-point links are required to connect 50 telephones together? 26304. 26305. A. 2255 26306. B. 1225 26307. C. 2250 26308. D. 1552 26309. 26310. 170. The first commercial switchboard was installed in 26311. 26312. A. Connecticut 26313. B. Boston 26314. C. Pennsylvania 26315. D. Washington 26316. 26317. 171. Where is a fax scanner found? 26318. 26319. A. at the end of fax signals 26320. B. at origin of fax signals 26321. C. at receive end of fax system 26322. D. at the input of a fax transmitter 26323. 26324. 172. What is the standard scanning LPI rates? 26325. 26326. A. 120 26327. B. 25 26328. C. 400 26329. D. 195 26330. 26331. 173. What tone is used to start fax? 26332. 26333. A. 400 Hz 26334. B. 100 Hz 26335. C. 300 Hz 26336. D. 500 Hz 26337. 26338. 174. What tone is used to stop fax? 26339. 26340. A. 450 Hz 26341. B. 500 Hz 26342. C. 150 Hz 26343. D. 250 Hz 26344. 26345. 175. What tones carry map information using facsimile? 26346. 26347. A. 1300 Hz and 2400 Hz 26348. B. 2400 Hz and 2500 Hz 26349. C. 1200 Hz and 2400 Hz 26350. D. 1500 Hz and 2300 Hz 26351. 26352. 176. The following frequencies are developed using 1.8 kHz used for scanner in facsimile, except: 26353. 26354. A. 300 Hz 26355. B. 100 Hz 26356. C. 450 Hz 26357. D. 60 Hz 26358. 26359. 177. To what is the output of a scanner fed in fax? 26360. 26361. A. transmitter 26362. B. receiver 26363. C. mixer 26364. D. oscillator 26365. 26366. 178. Basically, in facsimile, what is a scanner helix? 26367. 26368. A. clear sided drum with one turn scratch 26369. B. clear sided drum with two turn scratch 26370. C. opaque sided drum with one turn scratch 26371. D. opaque sided drum with two turn scratch 26372. 26373. 179. A recorder helix in facsimile? 26374. A. insulated drum with one turn wire 26375. B. opaque drum with one turn scratch 26376. C. clear sided with one turn wire 26377. D. insulated drum with one turn scratch 26378. 26379. 180. In fax, the following are scanner signals where the switcher switch in except: 26380. 26381. A. 300 Hz 26382. B. phasing signal 26383. C. 90 Hz 26384. D. map signals 26385. 26386. 181. With what type transmitter is fax transmitted on HF? 26387. 26388. A. AM 26389. B. FM 26390. C. PM 26391. D. SSB 26392. 26393. 182. With what type transmitter is fax transmitted on VHF? 26394. 26395. A. FM 26396. B. PM 26397. C. SSB 26398. D. AM 26399. 26400. 183. The helix wire forms one end of the circuit of facsimile; what forms the other? 26401. 26402. A. insulated wire 26403. B. drum 26404. C. blade 26405. D. transmit circuit 26406. 26407. 184. What emf is required across the circuit in facsimile to form a dark spot? 26408. 26409. A. 40 V 26410. B. 60 V 26411. C. 25 V 26412. D. 70 V 26413. 26414. 185. In a facsimile recorder what is used to make 1,500-Hz ac stronger than 2300 Hz? 26415. 26416. A. non-linear slope filter 26417. B. linear slope filter 26418. C. active slope filter 26419. D. passive slope filter 26420. 186. In a recorder of facsimile, what is used to generate 60-Hz ac? 26421. 26422. A. 3.0 kHz oscillator and logic gates 26423. B. 2.4 kHz mixer and logic gates 26424. C. 3.0 kHz oscillator and logic divider 26425. D. 2.4 kHz oscillator and logic divider 26426. 26427. 187. If the tuning meter reads full scale, what would this indicate in facsimile? 26428. 26429. A. 1300 signal 26430. B. 2400 signal 26431. C. 1400 signal 26432. D. 1500 signal 26433. 26434. 188. If the tuning meter reads midscale, what would this indicate in facsimile? 26435. 26436. A. average 26437. B. mistuned 26438. C. peak 26439. D. minimum 26440. 26441. 189. If the tuning meter reads low-scale, what would this indicate in facsimile? 26442. 26443. A. 1500 signal 26444. B. 1700 signal 26445. C. 2300 signal 26446. D. 2400 signal 26447. 26448. 190. Why is the blade an endless loop in facsimile? 26449. 26450. A. wears faster 26451. B. wears slower 26452. C. wears average speed 26453. D. never wears 26454. 26455. 191. What should bring the left margin of the map to the left side of the paper in the recorder of facsimile? 26456. 26457. A. map signals 26458. B. phasing signals 26459. C. automatic switch 26460. D. 90 Hz 26461. 26462. 26463. 26464. 26465. 26466. 26467. 26468. 26469. MULTIPLE CHOICE QUESTIONS IN 26470. FIBER OPTICS 26471. Electronics Systems and Technologies 26472. By 26473. Melvin C. Arceo 26474. 26475. 26476. 26477. 26478. 26479. 26480. 26481. 26482. 26483. 26484. ENCODED BY: 26485. RIVERA, Billy Joe S. 26486. 1. A device that was constructed from mirrors and selenium detectors that transmitted sound waves over a beam of light. 26487. 26488. A. lightphone 26489. B. photophone 26490. C. cameraphone 26491. D. walletphone 26492. 26493. 2. Which fiber-optic system is better? 26494. 26495. A. 3 repeaters 26496. B. 8 repeaters 26497. C. 11 repeaters 26498. D. 20 repeaters 26499. 26500. 3. What is the frequency limit of a copper wire? 26501. 26502. A. approximately 0.5 MHz 26503. B. approximately 1.0 MHz 26504. C. approximately 40 GHz 26505. D. none of the above 26506. 26507. 4. They were granted patents for scanning and transmitting television images through uncoated fiber cables. 26508. 26509. A. Baird and Hansel 26510. B. Bockham and Kao 26511. C. Kapron and Keck 26512. D. Maiman and Schawlow 26513. 26514. 5. The product of the bit rate and distance of a fiber-optic system is 2 Gbits-km/s. What is the maximum rate at 5 km? 26515. 26516. A. 100 Mbits/s 26517. B. 200 Mbits/s 26518. C. 400 Mbits/s 26519. D. 1000 Gbits/s 26520. 26521. 6. Approximately what is the frequency limit of the optical fiber? 26522. 26523. A. 20 MHz 26524. B. 1 MHz 26525. C. 100 MHz 26526. D. 40 GHz 26527. 26528. 7. They experimented with light transmission cables through bundle of fibers and lead to the development of flexible fiberscope. 26529. 26530. A. Townes, Schawlow and Kao 26531. B. Maiman, Kao and Bockham 26532. C. Maurer, Kapron and Keck 26533. D. Van Heel, Hopkins and Kapany 26534. 26535. 8. Photodiodes operate properly with 26536. 26537. A. forward bias 26538. B. reverse bias 26539. C. neither forward nor reverse bias 26540. D. either forward or reverse bias 26541. 26542. 9. He coined the term “fiber optics” in 1956. 26543. 26544. A. Kapany 26545. B. Kao 26546. C. Bockham 26547. D. Keck 26548. 26549. 10. They wrote a paper describing how it was possible to use stimulated emission for amplifying light waves (laser) as well as microwaves (maser). 26550. 26551. A. Theodore Maiman 26552. B. KC Kao and GA Bockham 26553. C. Charles Townes and Arthur Schawlow 26554. D. Kapron, Keck and Maurer 26555. 26556. 11. The scientist who built the first optical maser 26557. 26558. A. Charles Townes 26559. B. GA Bockham 26560. C. Theodore Maiman 26561. D. ACS Van Heel 26562. 26563. 12. A single fiber can handle as many voice channels as 26564. 26565. A. a pair of copper conductors 26566. B. a 1500-pair cable 26567. C. a 500-pair cable 26568. D. a 1000-pair cable 26569. 26570. 13. They proposed a new communication medium using cladded fiber cables. 26571. 26572. A. Kao and Bockham 26573. B. Maiman, Kao and Bockham 26574. C. Kapron, Keck and Maurer 26575. D. Maiman and Schawlow 26576. 26577. 14. An incident ray can be defined as 26578. 26579. A. a light ray reflected from a flat surface 26580. B. a light directed toward a surface 26581. C. a diffused light ray 26582. D. a light ray that happens periodically 26583. 26584. 15. Developed an optical fiber with losses less that 2 dB/km 26585. 26586. A. Kao and Bockham 26587. B. Maiman, Kao and Bockham 26588. C. Maiman and Schawlow 26589. D. Kapron, Keck and Maurer 26590. 26591. 16. The band of light frequencies that are too high to be seen by the human eye. 26592. 26593. A. Ultraviolet 26594. B. Visible light 26595. C. Infrared 26596. D. Yellow 26597. 26598. 17. Which of the following is the fastest light sensor? 26599. 26600. A. PIN photodiode 26601. B. Photovoltaic diode 26602. C. Photodiode 26603. D. Avalanche photodiode 26604. 26605. 18. Range of infrared 26606. 26607. A. 360 nm to 440 nm 26608. B. 670 nm to 10^3 nm 26609. C. 110 nm to 240 nm 26610. D. 770 nm to 10^6 nm 26611. 26612. 19. The term dispersion describes the process of 26613. 26614. A. separating light into its component frequencies 26615. B. reflecting light from a smooth surface 26616. C. the process by which light is absorbed by an uneven rough surface 26617. D. light scattering 26618. 20. The band of light frequencies to which human eye will respond 26619. 26620. A. Infrared 26621. B. Visible light 26622. C. Ultraviolet 26623. D. Cosmic ray 26624. 26625. 21. Laser light is very bright because it is 26626. 26627. A. pure 26628. B. white 26629. C. coherent 26630. D. monochromatic 26631. 26632. 22. Which of the following is the fastest light sensor? 26633. 26634. A. PIN photodiode 26635. B. Photovoltaic diode 26636. C. Photodiode 26637. D. Avalanche photodiode 26638. 26639. 23. Range of wavelength of visible light 26640. 26641. A. 670 nm to 10^3 nm 26642. B. 440 nm to 540 nm 26643. C. 110 nm to 240 nm 26644. D. 390 nm to 770 nm 26645. 26646. 24. The band of light frequencies that are too low to be seen by the human eye 26647. 26648. A. Infrared 26649. B. X-rays 26650. C. Visible 26651. D. Ultraviolet 26652. 26653. 25. Which of the following terms best describes the reason that light is refracted at different angles? 26654. 26655. A. Photon energy changes with wavelength 26656. B. Light is refracted as a function of surface smoothness 26657. C. The angle is determined partly by a and b 26658. D. The angle is determined by the index of the materials 26659. 26660. 26. Range of wavelengths of ultraviolet 26661. 26662. A. 670 nm to 10^3 nm 26663. B. 440 nm to 540 nm 26664. C. 110 nm to 240 nm 26665. D. 10 nm to 390 nm 26666. 26667. 27. Single frequency light is called 26668. 26669. A. pure 26670. B. intense 26671. C. coherent 26672. D. monochromatic 26673. 26674. 28. The coating in a fiber helps protect fiber from moisture, which reduces the possibility of the occurrence of a detrimental phenomenon called 26675. 26676. A. static fatigue 26677. B. mechanical fatigue 26678. C. stress fatigue 26679. D. coating fatigue 26680. 26681. 29. The term critical angle describes 26682. 26683. A. the point at which light is refracted 26684. B. the point at which light becomes invisible 26685. C. the point at which light has gone from the refractive mode to the reflective mode 26686. D. the point at which light has crossed the boundary layers from one index to another 26687. 26688. 30. The ratio of the speed of light in air to the speed of light in another substance is called 26689. 26690. A. speed factor 26691. B. index of reflection 26692. C. index of refraction 26693. D. speed gain 26694. 26695. 31. The three essential types of fiber commonly used today except: 26696. 26697. A. Plastic core and cladding 26698. B. Plastic core and glass cladding 26699. C. Glass core and glass cladding (SCS) 26700. D. Glass core and plastic cladding (PCS) 26701. 26702. 32. What phenomenon will result if the glass fiber is exposed to long periods of high humidity? 26703. 26704. A. stress fatigue 26705. B. core corrosion 26706. C. stress corrosion 26707. D. cladding corrosion 26708. 33. The law that states “When visible light of high frequency electromagnetic radiation illuminates a metallic surface, electrons are emitted” is known as ______. 26709. 26710. A. Einstein law of photon 26711. B. Marconi’s law 26712. C. Maxwell’s law 26713. D. Plank’s law 26714. 26715. 34. Both LEDs and ILDs operate correctly with 26716. 26717. A. forward bias 26718. B. reverse bias 26719. C. neither forward nor reverse bias 26720. D. either forward or reverse bias 26721. 26722. 35. Any energy above the ground state is called ______. 26723. 26724. A. normal state 26725. B. above-ground state 26726. C. excited state 26727. D. spontaneous state 26728. 26729. 36. The process of decaying from one energy level to another energy level is called ______. 26730. 26731. A. Spontaneous emission 26732. B. Excited emission 26733. C. Absorption 26734. D. Any of these 26735. 26736. 37. The process of moving from one energy level to another is called ______. 26737. 26738. A. Spontaneous emission 26739. B. Excited emission 26740. C. Absorption 26741. D. Spontaneous decay 26742. 26743. 38. Most fiber optic light sources emit light in which spectrum? 26744. 26745. A. visible 26746. B. infrared 26747. C. ultraviolet 26748. D. X-ray 26749. 26750. 39. A packet of energy which is equal to the difference between the two energy levels. 26751. 26752. A. Photons 26753. B. Electronvolt 26754. C. Quantum 26755. D. Quanta 26756. 26757. 40. It is the science of measuring only light waves that are visible to the human eye. 26758. 26759. A. Radiometry 26760. B. Photometry 26761. C. Ophthalmology 26762. D. Optometry 26763. 26764. 41. The refractive index number is 26765. 26766. A. a number which compares the transparency of a material with that of air 26767. B. a number of assigned by the manufacturer to the fiber in question 26768. C. a number which determines the core diameter 26769. D. a term describing core elasticity 26770. 26771. 42. It is a science of measuring light throughout the entire electromagnetic spectrum 26772. 26773. A. Radiometry 26774. B. Photometry 26775. C. Ophthalmology 26776. D. Optometry 26777. 26778. 43. Which light emitter is preferred for high-speed data in a fiber-optic system? 26779. 26780. A. incandescent 26781. B. LED 26782. C. neon 26783. D. laser 26784. 26785. 44. Light intensity is generally described in terms of ______and measured in ______. 26786. 26787. A. Luminous flux density; Lumens per unit area 26788. B. Luminous flux intensity; Lumens per unit area 26789. C. Luminous flux density; Lumens per unit volume 26790. D. Luminous flux intensity; Lumens per unit volume 26791. 26792. 45. In radiometric terms, it measures the rate at which electromagnetic waves transfer light energy 26793. 26794. A. Optical radiation 26795. B. Optical impedance 26796. C. Optical illusion 26797. D. Optical power 26798. 46. It is described as the flow of light energy past a given point in a specified time 26799. 26800. A. Optical radiation 26801. B. Optical impedance 26802. C. Optical illusion 26803. D. Optical power 26804. 26805. 47. The term single mode and multimode are best described as 26806. 26807. A. a number of fibers placed into fiber-optic cable 26808. B. the number of voice channels each fiber can support 26809. C. the number of wavelengths each fiber can support 26810. D. the index number 26811. 26812. 48. Optical power is sometimes called ______. 26813. 26814. A. Radiant emission 26815. B. Radiant power 26816. C. Radiant flux 26817. D. Radiant optics 26818. 26819. 49. In refraction that occurs in air/glass interfaces, among the visible light, which is bent the most? 26820. 26821. A. red 26822. B. violet 26823. C. yellow 26824. D. green 26825. 26826. 50. Fiber-optic cables with attenuation of 1.8, 3.4, 5.9 and 18 dB are linked together. The total loss is 26827. 26828. A. 7.5 dB 26829. B. 19.8 dB 26830. C. 29.1 dB 26831. D. 650 dB 26832. 26833. 51. In refraction that occurs in air/glass interfaces, among the visible light, which is the bent the least? 26834. 26835. A. violet 26836. B. blue 26837. C. red 26838. D. orange 26839. 26840. 52. Ratio of the velocity of propagation of a light ray in free space to the velocity of propagation of a light ray in free space in a given material. 26841. 26842. A. refractive index 26843. B. standing wave ratio 26844. C. velocity factor 26845. D. propagation velocity 26846. 26847. 53. It is the angle at which the propagating ray strikes the interface with respect to the normal. 26848. 26849. A. refracted angle 26850. B. incident angle 26851. C. reflected angle 26852. D. critical angle 26853. 26854. 54. It is the angle formed between the propagating ray and the normal after the ray has entered the second medium. 26855. 26856. A. angle of incidence 26857. B. angle of reflection 26858. C. propagation angle 26859. D. angle of refraction 26860. 26861. 55. Between silicon and gallium arsenide, which has the greatest index of refraction? 26862. 26863. A. Gallium arsenide 26864. B. Neither of silicon nor gallium arsenide 26865. C. Silicon 26866. D. They are equal 26867. 26868. 56. A fiber-optic cable has a loss of 15dB/km. The attenuation in a cable 1000 ft long is 26869. 26870. A. 4.57 dB 26871. B. 9.3 dB 26872. C. 24 dB 26873. D. 49.2 dB 26874. 26875. 57. Medium 1 is a glass (n1=1.5) and medium 2 is an ethyl alcohol (n2=1.36). For an angle of incidence of 30 degrees, determine the angle of refraction. 26876. 26877. A. 44.5 degrees 26878. B. 14.56 degrees 26879. C. 33.47 degrees 26880. D. 75 degrees 26881. 26882. 58. The minimum angle of incidence at which the light ray may strike the interface of two media and result in an angle of refraction of 90 degrees or greater. 26883. 26884. A. optimum angle 26885. B. angle of refraction 26886. C. refracted angle 26887. D. critical angle 26888. 26889. 59. The higher the index number 26890. 26891. A. the higher the speed of light 26892. B. the lower the speed of light 26893. C. has no effect on the speed of light 26894. D. the shorter the wavelength propagation 26895. 26896. 60. The maximum angle in which external light rays may strike the air/glass interface and still propagate down the fiber. 26897. 26898. A. Acceptance cone half-angle 26899. B. Acceptance cone 26900. C. Critical angle 26901. D. Angle of incidence 26902. 26903. 61. It is the figure of merit used to measure the magnitude of the acceptance angle. 26904. 26905. A. acceptance angle 26906. B. numerical aperture 26907. C. index profile 26908. D. refractive index 26909. 26910. 62. The effect of a large magnitude of the numerical aperture 26911. 26912. A. The amount of external light the fiber will accept is greater. 26913. B. The amount of external light the fiber will accept is less. 26914. C. The amount of modal dispersion will be less. 26915. D. The amount of chromatic dispersion will be greater. 26916. 26917. 63. Only one path for light rays to take down the fiber 26918. 26919. A. Multimode 26920. B. Step-index 26921. C. Single mode 26922. D. Graded index 26923. 26924. 64. More than one path for light rays to take down the fiber 26925. 26926. A. Multimode 26927. B. Step-index 26928. C. Single mode 26929. D. Graded index 26930. 26931. 65. The three major groups of the optical system are 26932. 26933. A. the components, the data rate and the response time 26934. B. the source, the link and the receiver 26935. C. the transmitter, the cable and the receiver 26936. D. the source, the link and the detector 26937. 26938. 66. Infrared light has a wavelength that is 26939. 26940. A. less than 400 nm 26941. B. more than 700 nm 26942. C. less than 700 nm 26943. D. a little over 400 nm 26944. 26945. 67. How many modes possible with a multimode step-index with a core diameter of 50 um, a core refractive index of 1.6, a cladding refractive index of 1.584, and a wavelength of 1300 nm. 26946. 26947. A. 456 26948. B. 213 26949. C. 145 26950. D. 372 26951. 26952. 68. It is a graphical representation of the magnitude of the refractive index across the fiber. 26953. 26954. A. mode 26955. B. index profile 26956. C. numerical aperture 26957. D. refractive index 26958. 26959. 69. A type of index profile of an optical fiber that has a central core and outside cladding with a uniform refractive index 26960. 26961. A. multimode 26962. B. graded index 26963. C. step-index 26964. D. single mode 26965. 26966. 70. A type of index of an optical fiber that has no cladding and whose central core has a non-uniform refractive index. 26967. 26968. A. graded index 26969. B. multimode 26970. C. single mode 26971. D. step-index 26972. 26973. 71. Results in reduction in the power of light wave as it travels down the cable. 26974. 26975. A. power loss 26976. B. absorption loss 26977. C. resistive loss 26978. D. heat loss 26979. 26980. 72. Which of the following is not a factor in cable light loss? 26981. 26982. A. reflection 26983. B. absorption 26984. C. scattering 26985. D. dispersion 26986. 26987. 73. It is analogous to power dissipation to copper cables, impurities in the fiber absorb the light and covert it to heat. 26988. 26989. A. power loss 26990. B. absorption loss 26991. C. resistive loss 26992. D. heat loss 26993. 26994. 74. It is caused by valence electrons in the silica material from which the fiber are manufactured. 26995. 26996. A. ion resonance absorption 26997. B. infrared absorption 26998. C. ultraviolet absorption 26999. D. visible light absorption 27000. 27001. 75. It is a result of photons of light that are absorbed by the atoms of the glass core molecule. 27002. 27003. A. ion resonance absorption 27004. B. infrared absorption 27005. C. ultraviolet absorption 27006. D. visible light absorption 27007. 27008. 76. It is caused by hydroxide ions in the material 27009. 27010. A. visible light absorption 27011. B. infrared absorption 27012. C. ultraviolet absorption 27013. D. ion resonance absorption 27014. 77. Which type of fiber-optic cable has the least modal dispersion? 27015. 27016. A. single-mode step-index 27017. B. multimode step-index 27018. C. single-mode graded-index 27019. D. multimode graded-index 27020. 27021. 78. For a single mode optical cable with 0.25dB/km loss, determine the optical power 100km from a 0.1-mW light source. 27022. 27023. A. -45 dBm 27024. B. -15 dBm 27025. C. -35 dBm 27026. D. -25dBm 27027. 27028. 79. Light rays that are emitted simultaneously from an LED and propagated down an optical fiber do not arrive at the far end of the fiber at the same time results to 27029. 27030. A. intramodal dispersion 27031. B. pulse length dispersion 27032. C. modal dispersion 27033. D. wavelength dispersion 27034. 27035. 80. Chromatic dispersion can be eliminated by ______. 27036. 27037. A. using a monochromatic light source 27038. B. using a very small numerical aperture fiber 27039. C. using a graded-index fiber 27040. D. using a very sensitive photodetector 27041. 27042. 81. Type of bend that occurs as a result of differences in thermal contraction rates between the core and the cladding material. 27043. 27044. A. Macrobending 27045. B. Microbending 27046. C. Quad bending 27047. D. Constant-radius bending 27048. 27049. 82. These bends are caused by excessive pressure and tension and generally occur while fiber are bent during handling or installation. 27050. 27051. A. microbending 27052. B. macrobending 27053. C. constant-radius bending 27054. D. kinks 27055. 27056. 83. As light is coupled in a multiport deflective device, the power is reduced by 27057. 27058. A. 1.5 dB 27059. B. 0.1 dB 27060. C. 0.5 dB 27061. D. 0.001 dB 27062. 27063. 84. It is caused by the difference in the propagation time of light rays that take different paths down the fiber. 27064. 27065. A. modal dispersion 27066. B. microbending 27067. C. Rayleigh scattering 27068. D. chromatic dispersion 27069. 27070. 85. How can modal dispersion reduced entirely? 27071. 27072. A. Use a graded index fiber 27073. B. Use a single-mode fiber 27074. C. Use a monochromatic light source 27075. D. Use a very sensitive light detector 27076. 27077. 86. It indicates what signal frequencies can be propagated through a given distance of fiber cable. 27078. 27079. A. Bandwidth Distance Product 27080. B. Pulse width dispersion 27081. C. Rise time 27082. D. Cutoff frequency 27083. 27084. 87. For a 300-m optical fiber cable with a bandwidth distance product of 600 MHz-km, determine the bandwidth. 27085. 27086. A. 5 GHz 27087. B. 1 GHz 27088. C. 2 GHz 27089. D. 3 GHz 27090. 27091. 88. For an optical fiber 10 km long with a pulse spreading constant of 5 ns/km, determine the maximum digital transmission rates using Return to Zero (RZ) and Nonreturn to Zero (NRZ). 27092. 27093. A. 5 Mbps and 10 Mbps 27094. B. 10 Mbps and 5 Mbps 27095. C. 10 Mbps and 20 Mbps 27096. D. 20 Mbps and 10 Mbps 27097. 27098. 89. What is the spectral width of a standard LED? 27099. 27100. A. 20 to 40 nm 27101. B. 30 to 50 nm 27102. C. 10 to 30 nm 27103. D. 40 to 60 nm 27104. 27105. 90. What is the spectral width of an ILD? 27106. 27107. A. 0.1 nm to 1 nm 27108. B. 2 nm to 5 nm 27109. C. 1 nm to 3 nm 27110. D. 3 nm to 4 nm 27111. 27112. 91. When connector losses, splice losses and coupler losses are added, what is the limiting factor? 27113. 27114. A. source power 27115. B. fiber attenuation 27116. C. connector and splice loss 27117. D. detector sensitivity 27118. 27119. 92. A pn-junction diode emits light by spontaneous emission 27120. 27121. A. LED 27122. B. APD 27123. C. PIN 27124. D. Zener diode 27125. 27126. 93. Which type of fiber optic cable is best for very high speed data? 27127. 27128. A. single-mode step-index 27129. B. multimode step-index 27130. C. single-mode graded-index 27131. D. multimode graded-index 27132. 27133. 94. A measure of conversion efficiency of a photodetector. 27134. 27135. A. Efficiency 27136. B. Responsivity 27137. C. Dark current 27138. D. Spectral response 27139. 27140. 95. The leakage current that flows through a photodiode with no light input 27141. 27142. A. dark voltage 27143. B. dark impedance 27144. C. dark power 27145. D. dark current 27146. 27147. 96. The time it takes a light induced carrier travel across the depletion region of the semiconductor. 27148. 27149. A. dispersion 27150. B. response time 27151. C. irradiance 27152. D. transit time 27153. 27154. 97. The range of wavelength values that a given photodiode will respond. 27155. 27156. A. spectral response 27157. B. permeance 27158. C. dark current 27159. D. reluctance 27160. 27161. 98. The term responsivity as it applies to a light detector is best described as 27162. 27163. A. the time required for the signal to go from 10 to 90 percent of maximum amplitude 27164. B. the ratio of the diode output current to the input optical power 27165. C. the ratio of the input power to output power 27166. D. the ratio of output current to input current 27167. 27168. 99. The minimum optical power a light detector can receive and still produce a usable electrical output signal. 27169. 27170. A. light responsivity 27171. B. light sensitivity 27172. C. light collectivity 27173. D. illumination 27174. 27175. 100. Type of lasers that uses a mixture of helium and neon enclosed in glass tube. 27176. 27177. A. gas lasers 27178. B. solid lasers 27179. C. semiconductor lasers 27180. D. liquid lasers 27181. 27182. 101. Type of lasers that use organic dyes enclosed in glass tube for an active medium. 27183. 27184. A. liquid lasers 27185. B. plasma lasers 27186. C. neon lasers 27187. D. ruby lasers 27188. 27189. 102. A popular light wavelength fiber-optic cable is 27190. 27191. A. 0.7 micrometer 27192. B. 1.3 micrometer 27193. C. 1.5 micrometer 27194. D. 1.8 micrometer 27195. 27196. 103. Type of lasers that use solid, cylindrical crystals such as ruby 27197. 27198. A. solid lasers 27199. B. ILD 27200. C. gas lasers 27201. D. liquid lasers 27202. 27203. 104. Type of lasers that are made from semiconductor ph-junctions commonly called ILDs 27204. 27205. A. semiconductor lasers 27206. B. liquid lasers 27207. C. plasma lasers 27208. D. gas lasers 27209. 27210. 105. Which of the following is not a common application of fiber-optic cable? 27211. 27212. A. computer networks 27213. B. long-distance telephone system 27214. C. closed-circuit TV 27215. D. consumer TV 27216. 27217. 106. Total internal reflection takes place if the light ray strikes the interface at an angle with what relationship to the critical angle? 27218. 27219. A. less than 27220. B. greater than 27221. C. equal to 27222. D. zero 27223. 27224. 107. Loss comparisons between fusion splices an mechanical splices 27225. 27226. A. 1:10 27227. B. 10:1 27228. C. 20:1 27229. D. 1:20 27230. 27231. 108. The operation of a fiber-optic cable is based on the principle of 27232. A. refraction 27233. B. reflection 27234. C. dispersion 27235. D. absorption 27236. 27237. 109. Which of the following is not a common type of fiber-optic cable? 27238. 27239. A. single-mode step-index 27240. B. multimode graded-index 27241. C. single-mode graded-index 27242. D. multimode step-index 27243. 27244. 110. Cable attenuation is usually expressed in terms of 27245. 27246. A. loss per foot 27247. B. dB/km 27248. C. intensity per mile 27249. D. voltage drop per inch 27250. 27251. 111. Which cable length has the highest attenuation? 27252. 27253. A. 1 km 27254. B. 2 km 27255. C. 95 ft 27256. D. 500 ft 27257. 27258. 112. The mechanical splice is best suited for 27259. 27260. A. quicker installation under ideal condition 27261. B. minimum attenuation losses 27262. C. field service conditions 27263. D. situations in which cost of equipment is not a factor 27264. 27265. 113. The upper pulse rate and information-carrying capacity of a cable is limited by 27266. 27267. A. pulse shortening 27268. B. attenuation 27269. C. light leakage 27270. D. modal dispersion 27271. 27272. 114. The core of a fiber-optic cable is made of 27273. 27274. A. air 27275. B. glass 27276. C. diamond 27277. D. quartz 27278. 115. The core of fiber-optic cable is surrounded by 27279. 27280. A. wire braid shield 27281. B. Keviar 27282. C. cladding 27283. D. plastic insulation 27284. 27285. 116. The speed of light in plastic compared to the speed of light in air is 27286. 27287. A. less 27288. B. more 27289. C. the same 27290. D. zero 27291. 27292. 117. Which of the following is not a major benefit of a fiber-optic cable? 27293. 27294. A. immunity from interference 27295. B. no electrical safety problems 27296. C. excellent data security 27297. D. lower cost 27298. 27299. 118. EMD is best described by which statement? 27300. 27301. A. 70 percent of the core diameter and 70% of the fiber NA should be filled with light. 27302. B. 70 percent of the fiber diameter and 70% of the cone of acceptance should be filled with light. 27303. C. 70 percent of input light should be measured at the output. 27304. D. 70 percent of the unwanted wavelengths should be attenuated by the fiber. 27305. 27306. 119. The main benefit of light wave communications over microwaves or any other communications media are 27307. 27308. A. lower cost 27309. B. better security 27310. C. wider bandwidth 27311. D. freedom from interface 27312. 27313. 120. Which of the following is not a part of the optical spectrum? 27314. 27315. A. infrared 27316. B. ultraviolet 27317. C. visible color 27318. D. x-rays 27319. 27320. 121. The wavelength of a visible extends from 27321. 27322. A. 0.8 to 1.6 um 27323. B. 400 to 750 nm 27324. C. 200 to 660 nm 27325. D. 700 to 1200 nm 27326. 27327. 122. Single-mode step-index cable has a core diameter in the range of 27328. 27329. A. 100 to 1000 micrometer 27330. B. 50 to 100 micrometer 27331. C. 2 to 15 micrometer 27332. D. 5 to 20 micrometer 27333. 27334. 123. Refraction is the 27335. 27336. A. bending of light 27337. B. reflection of light waves 27338. C. distortion of light waves 27339. D. diffusion of light waves 27340. 27341. 124. Which of the following cables will have the highest launch power capability? 27342. 27343. A. 50/125/0.2 27344. B. 85/125/0.275 27345. C. 62.5/125/0.275 27346. D. 100/140/0.3 27347. 27348. 125. Which type of fiber-optic cable is the most widely used? 27349. 27350. A. single-mode step-index 27351. B. multimode step-index 27352. C. single-mode graded index 27353. D. multimode graded index 27354. 27355. 126. The term power budgeting refers to 27356. 27357. A. the cost of cable, connectors, equipment and installation 27358. B. the loss of power due to defective components 27359. C. the total power available minus the attenuation losses 27360. D. the comparative costs of fiber and copper installations 27361. 27362. 127. It refers to the abrupt of change in refractive index from core to clad 27363. 27364. A. step index 27365. B. graded index 27366. C. semi-graded index 27367. D. half step index 27368. 27369. 27370. 27371. 27372. MULTIPLE CHOICE QUESTIONS IN 27373. AMPLITUDE MODULATION 27374. Electronics Systems and Technologies 27375. By 27376. Melvin C. Arceo 27377. 27378. 27379. 27380. 27381. 27382. 27383. 27384. 27385. ENCODED BY: 27386. SANTOLLO, Dan Alvin 27387. 1. The process of impressing a low frequency information signals onto a high- frequency carrier signal is called _____. 27388. a. demodulation 27389. b. oscillation 27390. c. modulation 27391. d. amplification 27392. 2. A silicon varactor diode exhibits a capacitance of 200pF at zero bias. If it is in parallel with a 60-pF capacitor and a 200-uH inductor, calculate the range of resonant frequency as the diode varies through a reverse bias of 3 to 15V. 27393. a. 679kHz to 2.13MHz 27394. b. 966kHz to 1.15MHz 27395. c. 355kHz to 3.12MHz 27396. d. 143 kHz to 4.53MHz 27397. 3. A process where the received signal is transformed into its original form. 27398. a. demodulation 27399. b. damping 27400. c. amplification 27401. d. oscillation 27402. 4. It is the process of changing the amplitude of a relative high frequency carrier signal in proportion with the instantaneous value of the modulating signal. 27403. a. frequency modulation 27404. b. digital modulation 27405. c. phase modulation 27406. d. analog modulation 27407. 5. Most of the power in an AM signal is in the 27408. a. carrier 27409. b. upper sideband 27410. c. lower sideband 27411. d. modulating signal 27412. 6. Amplitude modulation is the same as 27413. a. linear mixing 27414. b. analog multiplexing 27415. c. signal summation 27416. d. multiplexing 27417. 7. The shape of the amplitude-modulated wave is called ______. 27418. a. sidebands 27419. b. modulating signal 27420. c. envelope 27421. d. carrier signal 27422. 8. In a diode modulator, the negative half of the AM wave is supplied by 27423. a. tuned circuit 27424. b. transformer 27425. c. capacitor 27426. d. inductor 27427. 9. It is a term used to describe the amount of amplitude change present in an AM waveform. 27428. a. coefficient of modulation 27429. b. any of these 27430. c. depth of modulation 27431. d. modulation index 27432. 10. When the modulation index in an AM wave is greater than one it will cause ______. 27433. a. any of these 27434. b. splatter 27435. c. overmodulation 27436. d. buck-shot 27437. 11. The ideal value of modulation index in AM. 27438. a. 1 27439. b. 0 27440. c. 100 27441. d. infinity 27442. 12. When the amplitude of the information in an AM modulator is equal to zero, what is the value of the modulation index? 27443. a. 1 27444. b. 0 27445. c. 100 27446. d. infinity 27447. 13. Amplitude modulation can be produced by 27448. a. having the carrier vary a resistance 27449. b. having the modulating signal vary a capacitance 27450. c. varying the carrier frequency 27451. d. varying the gain of the amplifier 27452. 14. When the modulation index is equal to zero, the total transmitted power is equal to ______. 27453. a. one of the sidebands 27454. b. carrier 27455. c. double sidebands 27456. d. an AM wave 27457. 15. When the modulation takes place prior to the output element of the final stage of the transmitter, prior to the collector of the output transistor in a transistorized transmitter, this is called ______. 27458. a. high-level modulation 27459. b. low-level modulation 27460. c. zero-modulation 27461. d. constant modulation 27462. 16. A circuit that monitors the received signal level and sends a signal back to the RF and IF amplifiers to adjust their gain automatically. 27463. a. automatic phase control 27464. b. automatic gain control 27465. c. automatic frequency control 27466. d. automatic volume control 27467. 17. When the modulation takes place in the final element of the final stage where the carrier signal is at its maximum amplitude, it is called _____. 27468. a. constant modulation 27469. b. zero-modulation 27470. c. low-level modulation 27471. d. high-level modulation 27472. 18. If a superheterodyne receiver is tuned to a desired signal at 1000kHz and its conversion (local) oscillator is operating at 1300kHz, what would be the frequency of an incoming signal that would possibly cause image reception? 27473. a. 1600 kHz 27474. b. 2300 kHz 27475. c. 1250 kHz 27476. d. 3420 kHz 27477. 19. When modulation requires a much higher amplitude modulating signal to achieve a reasonable percent modulation, this is called 27478. a. high-level modulation 27479. b. low-level modulation 27480. c. zero-modulation 27481. d. constant modulation 27482. 20. Amplitude modulators that vary the carrier amplitude with the modulating signal by passing it through an attenuator work on principle of 27483. a. rectification 27484. b. resonance 27485. c. variable resistance 27486. d. absorption 27487. 21. A circuit which function is to raise the amplitude of the source signal to a usable level while producing minimum nonlinear distortion adding as little thermal noise as possible. 27488. a. power amplifier 27489. b. non-linear amplifier 27490. c. buffer amplifier 27491. d. preamplifier 27492. 22. A circuit that has a low-gain, high-input impedance linear amplifier which is used to isolate the oscillator from the high-power amplifiers. 27493. a. power amplifier 27494. b. bandpass filter 27495. c. signal driver 27496. d. buffer amplifier 27497. 23. With high-level transmitters, which of the following is not a primary function of the modulator circuit? 27498. a. it provides the capacity necessary for modulation to occur 27499. b. it serves as a final amplifier 27500. c. it serves as a frequency up-converter 27501. d. it serves as a mixer 27502. 24. It is a form of amplitude distortion introduced when positive and negative alternations in the AM modulated signal are not equal. 27503. a. phase shift 27504. b. carrier shift 27505. c. amplitude variations 27506. d. frequency shift 27507. 25. A carrier is simultaneously modulated by two sine waves with modulation indices of 0.3 and 0.4, the total modulation index 27508. a. is 1 27509. b. cannot be calculated unless the phase relations are known 27510. c. is 0.5 27511. d. is 0.7 27512. 26. The component used to produce AM AT very high frequencies is a 27513. a. varactor 27514. b. thermistor 27515. c. cavity resonator 27516. d. PIN diode 27517. 27. It is also known as upward modulation 27518. a. carrier shift 27519. b. amplitude variations 27520. c. frequency shift 27521. d. phase shift 27522. 28. Also known as downward modulation 27523. a. carrier shift 27524. b. amplitude variations 27525. c. frequency shift 27526. d. phase shift 27527. 29. It is a form of amplitude modulation where signals from two separate information sources modulate the same carrier frequency at the same time without interfering with each other. 27528. a. QPSK 27529. b. QUAM 27530. c. PSK 27531. d. FSK 27532. 30. A receiver has a dynamic range of 81 dB. It has 0.55nW sensitivity. Determine the maximum allowable input signal. 27533. a. 59 mW 27534. b. 69 mW 27535. c. 79 mW 27536. d. 88 mW 27537. 31. The information sources modulate the same carrier after it has been separated into two carrier signals are at 90 degrees out of phase with each other. 27538. a. QPSK 27539. b. QUAM 27540. c. PSK 27541. d. FSK 27542. 32. Demodulating quadrature AM signal requires a carrier recovery circuit to reproduce the original carrier frequency and phase and two balanced modulators to actually demodulate the signals. This is called ______. 27543. a. asynchronous detection 27544. b. quadrature demodulation 27545. c. synchronous detection 27546. d. quadrature detection 27547. 33. Quadrature amplitude modulation is also known as ______. 27548. a. phase division multiplexing 27549. b. phase division modulation 27550. c. phase amplitude multiplexing 27551. d. phase angle modulation 27552. 34. Amplitude modulation generated at a very low voltage or power amplitude is known as 27553. a. high-level modulation 27554. b. low-level modulation 27555. c. collector modulation 27556. d. minimum modulation 27557. 35. It is the first stage of the receiver and is therefore often called the receiver front end. 27558. a. mixer 27559. b. RF section 27560. c. local oscillator 27561. d. IF stage 27562. 36. In an SSB transmitter, one is most likely to find a 27563. a. class C audio amplifier 27564. b. tuned modulator 27565. c. class B RF amplifier 27566. d. class A RF output amplifier 27567. 37. The section of the receiver than down-converts the received RF frequencies to intermediate frequencies. 27568. a. RF section 27569. b. local oscillator 27570. c. power amplifier 27571. d. mixer 27572. 38. The circuit that demodulates the AM wave and converts it to the original information signal. 27573. a. power amplifier 27574. b. local oscillator 27575. c. detector 27576. d. IF section 27577. 39. A collector modulator has a supply voltage of 48V. The peak-to-peak amplitude of the modulating signal for 100 percent modulation is 27578. a. 24V 27579. b. 48V 27580. c. 96V 27581. d. 120V 27582. 41. The noise reduction ratio achieved by reducing the bandwidth is called 27583. a. dynamic range 27584. b. noise figure 27585. c. bandwidth efficiency 27586. d. bandwidth improvement 27587. 42. It is the minimum RF signal level that can be detected at the input to the receiver and still produce a usable demodulated information signal. 27588. a. selectivity 27589. b. sensitivity 27590. c. Q-factor 27591. d. bandwidth 27592. 43. For ideal AM, which of the following is true 27593. a. m = 0 27594. b. m = 1 27595. c. m < 1 27596. d. m > 1 27597. 46. It is defined as the difference in decibels between the minimum input level necessary to discern the signal and the input level that will overdrive the receiver and produce distortion. 27598. a. dynamic range 27599. b. noise figure 27600. c. bandwidth efficiency 27601. d. bandwidth improvement 27602. 47. It is the input power range over which the receiver is useful. 27603. a. dynamic range 27604. b. noise figure 27605. c. bandwidth efficiency 27606. d. bandwidth improvement 27607. 48. It is defined as the output power when the RF amplifier response is 1-dB less than the ideal linear gain response. 27608. a. 1-dB compression point 27609. b. 1-dB threshold point 27610. c. 1-dB shoot-off point 27611. d. 1-dB pinch-off point 27612. 49. It is the measure of the ability of a communications system to produce, at the output of the receiver, an exact replica of the original source information. 27613. a. sensitivity 27614. b. threshold 27615. c. selectivity 27616. d. fidelity 27617. 50. A SSB signal generated around a 200-kHz carrier. Before filtering, the upper and lower sidebands are separated by 200 Hz. Calculate the filter Q required to obtain 40- dB suppression. 27618. a. 1500 27619. b. 1900 27620. c. 2500 27621. d. 2000 27622. 51. The predominant cause of phase distortion. 27623. a. overmodulation 27624. b. buffering 27625. c. filtering 27626. d. clipping 27627. 52. It is the total phase shift encountered by a signal and can generally be tolerated as long as all frequencies undergo the same amount of phase delay. 27628. a. differential phase shift 27629. b. absolute phase shift 27630. c. relative phase shift 27631. d. integrated phase shift 27632. 53. ______occurs when different frequencies undergo different phase shifts and may have a detrimental effect on the complex waveform. 27633. a. differential phase shift 27634. b. absolute phase shift 27635. c. relative phase shift 27636. d. integrated phase shift 27637. 54. What is the minimum AM signal needed to transmit information 27638. a. carrier plus sidebands 27639. b. carrier only 27640. c. one sideband 27641. d. both sidebands 27642. 55. The circuit that recovers the original modulating information from an AM signal is known as a 27643. a. modulator 27644. b. demodulator 27645. c. mixer 27646. d. crystal set 27647. 56. ______occurs when the amplitude-versus-frequency characteristics of a signal at the output of a receiver cover from those in the original information signal. 27648. a. frequency distortion 27649. b. digital distortion 27650. c. phase distortion 27651. d. amplitude distortion 27652. 57. The circuit used to produced modulations called 27653. a. modulator 27654. b. demodulator 27655. c. variable gain amplifier 27656. d. multiplexer 27657. 58. It is the result pf non-uniform gain in amplifiers and filters. 27658. a. harmonic distortion 27659. b. amplitude distortion 27660. c. frequency distortion 27661. d. phase distortion 27662. 59. It is a result of harmonic and intermodulation distortion and is caused by non- linear amplification. 27663. a. amplitude distortion 27664. b. phase distortion 27665. c. harmonic distortion 27666. d. frequency distortion 27667. 60. The most commonly used amplitude demodulator is the 27668. a. diode mixer 27669. b. balanced modulator 27670. c. envelope detector 27671. d. crystal filter 27672. 61. It is a special case of intermodulation distortion and a predominant cause of frequency distortion. 27673. a. second-order intercept distortion 27674. b. phase distortion 27675. c. third-order intercept distortion 27676. d. first-order intercept distortion 27677. 62. A display of signal amplitude versus frequency is called the 27678. a. time domain 27679. b. frequency spectrum 27680. c. amplitude modulation 27681. d. frequency domain 27682. 63. It is a parameter associated with frequencies that fall within the passband of the filter. 27683. a. coupling loss 27684. b. diffusion loss 27685. c. insertion loss 27686. d. filter loss 27687. 64. A circuit that generates the upper and lower sidebands but no carrier is called 27688. a. amplitude modulator 27689. b. diode detector 27690. c. class C amplifier 27691. d. balanced modulator 27692. 65. Vestigial sideband modulation (C3F) is normally used for 27693. a. HF point-to-point communications 27694. b. monaural broadcasting 27695. c. TV broadcasting 27696. d. stereo broadcasting 27697. 66. It is generally defined as the ratio of the power transferred to a load with a filter in the circuit to the power transferred to a load without a filter. 27698. a. distortion loss 27699. b. insertion loss 27700. c. filter loss 27701. d. harmonic loss 27702. 67. The modulation index of an AM wave is changed from 0 to 1. The transmitted power is 27703. a. unchanged 27704. b. halved 27705. c. doubled 27706. d. increased by 50 percent 27707. 68. The inputs to a balanced modulator are 1MHz and a carrier of 1.5 MHz. The outputs are 27708. a. 500kHz and 1.5MHz 27709. b. 2.5MHz and 1.5MHz 27710. c. 1.5MHz and 500kHz 27711. d. 500kHz and 2.5MHz 27712. 69. It is an indication of the reduction the signal-to-noise ration as a signal propagates through the receiver. 27713. a. noise figure 27714. b. equivalent noise temperature 27715. c. noise factor 27716. d. signal-to-noise ratio 27717. 70. Types of receivers where the frequencies generated in the receiver and used for demodulation are synchronized to oscillator frequencies generated in the transmitter. 27718. a. coherent 27719. b. asynchronous 27720. c. non-coherent 27721. d. none of these 27722. 71. Types of receiver where either no frequencies are generated in the receiver of the frequencies used for demodulation are completely independent form the transmitter's carrier frequency. 27723. a. synchronous 27724. b. coherent 27725. c. asynchronous 27726. d. any of these 27727. 72. A widely used balanced modulator is called the ______. 27728. a. diode bridge circuit 27729. b. full-wave bridge rectifier 27730. c. lattice modulator 27731. d. balanced bridge modulator 27732. 73. Non-coherent detection is also known as ______. 27733. a. frequency detection 27734. b. noise detection 27735. c. phase detection 27736. d. envelope detection 27737. 74. It is one of the earliest type of AM receiver 27738. a. TRF 27739. b. transistorized 27740. c. superhet 27741. d. Armstrong 27742. 75. Which of the following is not true about the disadvantages of tuned radio frequency receiver? 27743. a. their bandwidth is inconsistent and varies with center frequency when tuned over a wide range of input frequencies 27744. b. it is unstable due to the large number of RF amplifiers all tuned to the same center frequency 27745. c. their gains are not uniform over a very wide frequency range 27746. d. it is very complex to construct 27747. 76. In a diode ring modulator, the diode acts like 27748. a. variable resistors 27749. b. switches 27750. c. rectifiers 27751. d. variable capacitors 27752. 77. It means to mix two frequencies together in a non-linear device or to translate on frequency to another using non-linear mixing. 27753. a. oscillation 27754. b. heterodyne 27755. c. modulation 27756. d. amplification 27757. 78. An AM transmitter antenna current is measured with no modulation and found to be 2.6 amperes. With modulation, the current rises to 2.9 amperes. The percentage modulation is 27758. a. 35% 27759. b. 70% 27760. c. 42% 27761. d. 89% 27762. 79. Its primary purpose is to provide enough initial bandlimiting to prevent a specific unwanted radio frequency from entering the receiver. 27763. a. detector 27764. b. predetector 27765. c. preselector 27766. d. mixer 27767. 80. It function is to reduce the noise bandwidth of the receiver and provides initial step 27768. toward reducing the overall receiver bandwidth to the minimum bandwidth required to pass the information signals. 27769. a. preselector 27770. b. detector 27771. c. mixer 27772. d. predetector 27773. 81. The output of a balanced modulator is 27774. a. AM 27775. b. FM 27776. c. SSB 27777. d. DSB 27778. 82. What is the first active device encountered by the received signal in the receiver? 27779. a. mixer 27780. b. RF amplifier 27781. c. local oscillator 27782. d. detector 27783. 83. The IF section is also known as 27784. a. bandpass filters 27785. b. IF strip 27786. c. IF filter 27787. d. intermediate filters 27788. 84. The detector in an AM receiver is known as 27789. a. audio detector 27790. b. power detector 27791. c. first detector 27792. d. amplitude limiter 27793. 85. A carrier of 880kHz is modulated by a 3.5 kHz sine wave. The LSB and USB are, respectively 27794. a. 873 and 887kHz 27795. b. 876.5 and 883.5kHz 27796. c. 883.5 and 876.5kHz 27797. d. 887 and 873kHz 27798. 86. The most commonly used filter in SSB generators uses 27799. a. LC networks 27800. b. mechanical resonators 27801. c. crystals 27802. d. RC networks and op-amps 27803. 87. Its purpose of the detector section is to convert the IF signals back to the original source information. 27804. a. mixer 27805. b. audio amplifier 27806. c. converter 27807. d. detector 27808. 88. It means that the two adjustments are mechanically tied together so that a single adjustment will change the center frequency of the preselector, at the same time, change the oscillator frequency. 27809. a. high-side injecting 27810. b. low-side injecting 27811. c. gang tuning 27812. d. local oscillator tracking 27813. 89. In a low-level AM system, amplifiers following the modulated stage must be 27814. a. linear devices 27815. b. harmonic devices 27816. c. class C amplifiers 27817. d. nonlinear devices 27818. 90. When the local oscillator is tuned above the radio frequency, it is called 27819. a. local oscillator tracking 27820. b. low-side injection 27821. c. gang tuning 27822. d. high-side injection 27823. 91. The equivalent circuit of a quartz us a 27824. a. series resonant circuit 27825. b. parallel resonant circuit 27826. c. none of these 27827. d. series and parallel resonant circuit 27828. 92. It is the ability of the local oscillator in a receiver to oscillate either above or below the selected radio frequency carrier by an amount equal to the intermediate frequency throughout the entire radio frequency brand. 27829. a. tracking 27830. b. mixing 27831. c. heterodyning 27832. d. tuning 27833. 93. The difference between the actual local oscillator frequency and the desired frequency is called ______. 27834. a. mixing error 27835. b. gang error 27836. c. tracking error 27837. d. quantizing error 27838. 94. What technique is used to prevent tracking error? 27839. a. using RLC circuit 27840. b. using tuned circuit 27841. c. using three-point tracking 27842. d. using ganged capacitors 27843. 95. a crystal lattice filter has a crystal frequencies pf 27.5 and 27.502MHz. The bandwidth is approximately 27844. a. 2kHz 27845. b. 3kHz 27846. c. 27.501MHz 27847. d. 55.502MHz 27848. 96. ______is any frequency other than selected radio frequency carrier that, if allowed to enter a receiver and mix it with local oscillator, will produce a cross- product frequency that is equal to the intermediate frequency 27849. a. image frequency 27850. b. intermediate frequency 27851. c. aliasing frequency 27852. d. ghost 27853. 97. It is a equivalent to a second radio frequency that will produce an IF that will interfere with the IF from the desired radio frequency. 27854. a. aliasing frequency 27855. b. image frequency 27856. c. interference 27857. d. intermediate frequency 27858. 98. An SSB generator has a sideband filter centered at 3.0MHz. The modulating signal is 3kHz. To produce both upper and lower sidebands, the following carrier frequencies must be produced: 27859. a. 2.7 and 3.3MHz 27860. b. 3.3 and 3.6MHz 27861. c. 2997 and 3003kHz 27862. d. 3000 and 3003kHz 27863. 99. It is a numerical measure of the ability of the preselector to reject the image frequency. 27864. a. image frequency rejection ratio 27865. b. noise figure 27866. c. numerical aperture 27867. d. signal-to-noise ratio 27868. 100. ______occurs when a receiver picks up the same station at two nearby points on the receiver tuning dial. 27869. a. spurious pointing 27870. b. under coupling 27871. c. double spotting 27872. d. optimal coupling 27873. 101. In the phasing method of SSB generation, one sideband is cancelled due out to 27874. a. phase shift 27875. b. sharp selectivity 27876. c. carrier suppression 27877. d. phase inversion 27878. 102. It is caused by poor front-end selectivity or inadequate image frequency rejection. 27879. a. optimal coupling 27880. b. double spotting 27881. c. spurious pointing 27882. d. under coupling 27883. 103. It is a high-gain, low noise, tuned amplifier that, when used is the first active encountered by the receiver signal. 27884. a. mixer 27885. b. local oscillator 27886. c. RF amplifier 27887. d. detector 27888. 104. It is a high performance microwave receiver at the input stage. In the RF section of optimize their noise figure. 27889. a. high-power amplifier 27890. b. low noise amplifier 27891. c. buffer amplifier 27892. d. local oscillator 27893. 105. A balanced modulator used to demodulates a SSB signal is called 27894. a. transponder 27895. b. product detector 27896. c. converter 27897. d. modulator 27898. 106. Which of the following is not the other name of a balanced modulator? 27899. a. balanced mixer 27900. b. product detector 27901. c. product modulator 27902. d. none of these 27903. 107. ______amplifiers are relatively high gain tuned amplifiers that are very similar to RF amplifiers, except that it operates over a relatively narrow, fixed frequency band. 27904. a. IF amplifiers 27905. b. low-noise amplifiers 27906. c. buffer amplifiers 27907. d. high-power amplifier 27908. 108. Type of tuned circuit where both the primary and secondary sides of the transformer are tuned tank circuits 27909. a. RLC tuned circuit 27910. b. double-tuned circuit 27911. c. single-tuned circuit 27912. d. LC tuned circuit 27913. 109. Frequency translation is done with a circuit called ______. 27914. a. summer 27915. b. multiplier 27916. c. filter 27917. d. mixer 27918. 110. Low noise RF amplifiers use what type biasing? 27919. a. class A 27920. b. class B 27921. c. class AB 27922. d. class C 27923. 111. Its purpose is to down-convert the incoming radio frequencies to intermediated frequencies. 27924. a. local oscillator 27925. b. RF amplifier 27926. c. detector 27927. d. mixer 27928. 112. It is a non-linear amplifier similar to modulator, except that the output is turned to different between the RF and local oscillator frequencies. 27929. a. RF amplifier 27930. b. local oscillator 27931. c. mixer 27932. d. detector 27933. 113. Mixing for frequency conversion is the same as 27934. a. rectification 27935. b. AM 27936. c. linear summing 27937. d. filtering 27938. 114. The most common technique used for coupling IF amplifiers 27939. a. resistive coupling 27940. b. inductive coupling 27941. c. capacitive coupling 27942. d. direct coupling 27943. 115. When the modulation index of an AM wave doubled, the antenna current is also doubled. The AM system being used is 27944. a. single-sideband, full carrier (H3E) 27945. b. vestigial sideband (C3F) c. single sideband, suppressed carrier (J3E) 27946. d. double sideband, full carrier (A3E) 27947. 116. The ability of a coil to induce a voltage within its own windings is called 27948. a. mutual inductance 27949. b. coefficient coupling 27950. c. self- inductance 27951. d. inductance 27952. 117. If the carrier of a 100 percent modulated AM wave is suppressed the precentage power saving will be 27953. a. 50 27954. b. 150 27955. c. 100 27956. d. 66.66 27957. 118. The ability of one coil to induce a voltage in another coil is called ______. 27958. a. coefficient coupling 27959. b. mutual inductance 27960. c. inductance 27961. d. self-inductance 27962. 119. Which of the following cam be used as a mixer? 27963. a. balanced modulator 27964. b. FET 27965. c. diode modulator 27966. d. all of the above 27967. 120. It is the ratio of the secondary flux to primary flux 27968. a. Q factor 27969. b. coefficient coupling 27970. c. self-inductance 27971. d. coefficient of modulation 27972. 121. Type of coupling where the secondary voltage is relatively low and the bandwidth is narrow. 27973. a. tight coupling 27974. b. optimum coupling 27975. c. loose coupling 27976. d. critical coupling 27977. 122. An AM signal, transmitted information is contained within the 27978. a. carrier 27979. b. modulating signal 27980. c. sidebands 27981. d. envelope 27982. 123. Typer of coupling which has high gain and a broad bandwidth 27983. a. optimum coupling 27984. b. tight coupling 27985. c. double coupling 27986. d. loose coupling 27987. 124. It is the point where the reflected resistance is equal to primary resistance and the Q of the primary tank circuit is halved and the bandwidth doubled. 27988. a. critical coupling 27989. b. tight coupling 27990. c. loose coupling 27991. d. optimum coupling 27992. 125. The desired output from a mixer is usually selected with a 27993. a. phase-shift circuit 27994. b. crystal filter 27995. c. resonant circuit 27996. d. transformer 27997. 126. It is caused by the reactive element of the reflected impedance being significant enough to change the resonant frequency of the primary tuned circuit. 27998. a. optimum coupling 27999. b. critical coupling 28000. c. double peaking 28001. d. flux linkage 28002. 127. IF transformers come as specially designed tuned circuits in groundable metal packages called ______. 28003. a. IF cans 28004. b. IF container 28005. c. IF strip 28006. d. IF tetrapack 28007. 128. The AM detector is sometimes called ______. 28008. a. first detector 28009. b. third detector 28010. c. second detector 28011. d. fourth detector 28012. 129. The mixer is sometimes called ______. 28013. a. first detector 28014. b. third detector 28015. c. second detector 28016. d. fourth detector 28017. 130. The two inputs to a mixer are the signal to be translated and a signal from 28018. a. modulator 28019. b. filter 28020. c. antenna 28021. d. local oscillator 28022. 131. AM demodulator is commonly called ______. 28023. a. phase detector 28024. b. peak detector 28025. c. frequency detector 28026. d. transistor detector 28027. 132. A type of detector that detects the shape of the input envelope 28028. a. peak detector 28029. b. phase detector 28030. c. diode detector 28031. d. shape detector 28032. 133. The ratio of the peak modulating signal voltage to the peak carrier voltage is referred to as 28033. a. voltage ratio 28034. b. decibels 28035. c. modulation index 28036. d. mix factor 28037. 134. A circuit that automatically increases the receiver gain for weak RF input levels and automatically decreases the receiver gain when a strong RF signal is received. 28038. a. automatic volume control 28039. b. automatic frequency control 28040. c. automatic gain control 28041. d. automatic phase control 28042. 135. Which is not a type of AGC? 28043. a. simple AGC 28044. b. forward AGC 28045. c. delayed AGC 28046. d. complex AGC 28047. 136. The value Vmax and Vmin as read from AM wave on an oscilloscope are 3.0 and 2.8. The percentage of modulation is 28048. a. 10 percent 28049. b. 41.4 percent 28050. c. 80.6 percent 28051. d. 93.3 percent 28052. 137. Amplitude modulation is used for broadcasting because 28053. a. it is more noise immune than other modulation systems 28054. b. compared to other systems it requires less transmitting power 28055. c. its use avoids receiver complexity 28056. d. no other modulation system can provide the necessary bandwidth for high fidelity 28057. 138. Type of AGC that prevents the AGC feedback voltage from reaching the RF or IF amplifiers until the RF level exceeds a predetermined magnitude. 28058. a. forward AGC 28059. b. delayed AGC 28060. c. complex AGC 28061. d. simple AGC 28062. 139. A circuit with a purpose to quiet a receiver in the absence of a received signal. 28063. a. automatic gain control 28064. b. automatic frequency control 28065. c. squelch circuit 28066. d. automatic volume control 28067. 140. A section of a audio stage of a receiver that removes sporadic, high amplitude noise transients of short duration, such as impulse noise. 28068. a. squelch circuit 28069. b. clampers 28070. c. clippers 28071. d. peak detector 28072. 141. A circuit that detects the occurrence of a high-amplitude, short duration noise spike then mutes the receiver by shutting off a portion of the receiver of the duration of the pulse. 28073. a. squelch circuit 28074. b. limiter 28075. c. clamper 28076. d. blanking circuit 28077. 142. The opposite modulation is 28078. a. reverse modulation 28079. b. downward modulation 28080. c. unmodulation 28081. d. demodulation 28082. 143. For good imag-frequency rejection, what is the desired value of the intermediate frequency? 28083. a. relatively low IF 28084. b. very low IF 28085. c. relatively high IF 28086. d. very high IF 28087. 144. With high-gain selective amplifiers that are stable and easily neutralized. what is the desired value of intermediate frequency? 28088. a. low IF 28089. b. medium IF 28090. c. high IF 28091. d. very high IF 28092. 145. It is defined as the ratio of the demodulated signal level at the output receiver to the RF signal level at the input to the receiver. 28093. a. received signal level 28094. b. figure of merit 28095. c. effective radiated power 28096. d. net receiver gain 28097. 146. It is the process of modifying the characteristic of one signal in accordance with some characteristic of another signal. 28098. a. multiplexing 28099. b. mixing 28100. c. modulation 28101. d. summing 28102. 147. The imaginary line on the carrier waveform of the amplitude modulated signal is called ______. 28103. a. sidebands 28104. b. envelope 28105. c. spurious emission 28106. d. information 28107. 148. Indicate the false statement regarding the advantages of the phase cancellation method of obtaining SSB over the filter method is false: 28108. a. more channel space available 28109. b. transmitter circuits must be stable, giving better spectrum 28110. c. the signal is more noise resistant 28111. d. much less power is required for the same signal strength 28112. 149. Indicate which one of the following advantages of the phase cancellation method of obtaining SSB over the filter method is false: 28113. a. switching from one sideband to the other simpler 28114. b. it is possible to generated SSB at any frequency 28115. c. SSB with lower audio frequencies present can be generated. 28116. d. There are more balanced modulators, therefore the carrier is suppressed better 28117. 150. The most commonly used filters is SSB generation are 28118. a. mechanical 28119. b. RC 28120. c. LC 28121. d. low-pass 28122. 152.One of the following cannot be used to remove the unwanted sideband in SSB. This is the 28123. a. filter system 28124. b. phase-shift method 28125. c. third method 28126. d. balanced modulator 28127. 153. R3E modulation is sometimes used to 28128. a. allow the receiver to have a frequency synthesizer 28129. b. simplify the frequency stability problem in reception 28130. c. reduce the power that must be transmitted 28131. d. reduce the bandwidth required for transmission 28132. 154. To provide two or more voice circuits with the same carrier, it is necessary to use 28133. a. ISB 28134. b. carrier reinsertion 28135. c. SSB with pilot carrier 28136. d. Lincomplex 28137. 155. A type of AGC is similar to conventional AGC except that the receive signal is monitored closer to the front end of the receiver and the correction voltage is fed forward to the IF amplifiers 28138. a. ISB 28139. b. delayed AGC 28140. c. complex AGC 28141. d. simple AGC 28142. 156. Having an information signal change some characteristics of a carrier signal is called 28143. a. multiplexing 28144. b. modulation 28145. c. duplexing 28146. d. linear mixing 28147. 157. A circuit that compensates for minor variations in the received RF signal level 28148. a. automatic volume control 28149. b. automatic frequency control 28150. c. automatic gain control 28151. d. automatic phase control 28152. 158. Which of the following is not true about AM? 28153. a. the carrier amplitude varies 28154. b. the carrier frequency remains constant 28155. c. the carrier frequency changes 28156. d. the information signal amplitude changes the carrier amplitude 28157. 159. A modulator circuit performs what mathematical operation on its two inputs? 28158. a. addition 28159. b. multiplication 28160. c. division 28161. d. square root 28162. 160. If m is greater than 1, what happens? 28163. a. normal operation 28164. b. carrier drops to 0 28165. c. information signal is distorted 28166. 161. The outline of the peaks of a carrier has the shape of modulating signal and is called ______. 28167. a. trace 28168. b. wave shape 28169. c. envelope 28170. d. carrier variation 28171. 162. Overmodulation occurs when 28172. a. Vm > Vc 28173. b. Vm < Vc 28174. c. Vm = Vc 28175. d. Vm = Vc = 0 28176. 163. The new signal produced by modulation are called ______. 28177. a. spurious emission 28178. b. harmonics 28179. c. intermodulation products 28180. d. sidebands 28181. 164. An AM signal has a carrier power of 5W, the percentage of modulation is 80 pecent. The total power sideband is ______. 28182. a. 0.8 W 28183. b. 1.6 W 28184. c. 2.5 W 28185. d. 4.0 W 28186. 165. For 100 percent modulation, what percentage of power is in each sideband 28187. a. 25 percent 28188. b. 33.3 percent 28189. c. 50 percent 28190. ` d. 100 percent 28191. 166. An AM transmitter has a percentage of modulation of 88, the carrier power is 440 W. The power in one sideband is 28192. a. 85 W 28193. b. 110 W 28194. c. 170 W 28195. d. 610 W 28196. 167. An AM signal without the carrier is called ______. 28197. a. SSB 28198. b. vestigial sidebands 28199. c. FM signal 28200. d. DSB 28201. 168. It is a form of amplitude modulation in which the carrier is transmitted at full power, but only one of the sidebands is transmitted. 28202. a. SSBFC 28203. b. SSBSC 28204. c. SSBRC 28205. d. ISB 28206. 169. With single-sideband full carrier, 100% modulation would mean a carrier power of how many percent of the total transmitted power? 28207. a. 80% 28208. b. 20% 28209. c. 50% 28210. d. 40% 28211. 170. It is a form of amplitude modulation in which the carrier is suppressed and one of the sidebands removed 28212. a. SSBFC 28213. b. ISB 28214. c. vestigial sideband 28215. d. SSBSC 28216. 171. It is a form of amplitude modulation in which one sideband is totally removed and the carrier voltage is reduced to approximately 10% of its unmodulated amplitude 28217. a. inderpendent sideband 28218. b. SSBFC 28219. c. SSBRC 28220. d. SSBSC 28221. 172. It is a form of amplitude modulation in which a single carrier frequency is independently modulated by two different modulating signal. 28222. a. vestigial sideband 28223. b. DSBFC 28224. c. independent sideband 28225. d. SSBFC 28226. 173. It is a form of amplitude modulation in which the carrier and one complete sideband are transmitted, but only part of the second sideband is transmitted. 28227. a. independent sideband 28228. b. vestigial sideband 28229. c. DSBFC 28230. d. SSBSC 28231. 174. It is the rms power developed at the crest of the modulation envelope of SSBSC. 28232. a. carrier power 28233. b. total transmitted power 28234. c. sideband power 28235. d. peak envelope power 28236. 175. Which of the following is not true about single-sideband transmission? 28237. a. power is conserved 28238. b. selective fading is eliminated 28239. c. bandwidth is conserved 28240. d. tuning is easy 28241. 176.A circuit that produces a double sideband suppressed carrier signal is called ______. 28242. a. filter 28243. b. mixer 28244. c. demodulator 28245. d. balanced modulator 28246. 177. A balanced modulator is sometimes called ______. 28247. a. balanced ring modulator 28248. b. balanced resistor modulator 28249. c. balanced lattice modulator 28250. d. any of these 28251. 178. A type of filter that receives electrical energy, converts it to mechanical vibrations and then converts the vibrations back to electrical energy at its output. 28252. a. crystal filter 28253. b. mechanical filter 28254. c. LC filter 28255. d. SAW filter 28256. 179. A type of filter that uses acoustic energy rather than electromechanical energy to provide excellent performance for precise bandpass filtering. 28257. a. SAW filter 28258. b. RC filter 28259. c. mechanical filter 28260. d. crystal filter 28261. 180. The difference between the IF and the BFO frequencies is called ______. 28262. a. information signal 28263. b. beat frequency 28264. c. carrier signal 28265. d. heterodyned signal 28266. 181. It is a circuit which is a narrowband PLL that tracks the pilot carrier in the composite SSBRC receiver signal and uses the recovered carrier to regenerate coherent local oscillator frequencies in the synthesizer. 28267. a. beat frequency oscillator 28268. b. mechanical filter 28269. c. local oscillator 28270. d. carrier recovery circuit 28271. 182. A system that provides narrowband voice communications for land mobile services with nearly the quality achieved with FM systems and do it using less than one- third the bandwidth. 28272. a. SSBSC 28273. b. DSBFC 28274. c. ACSSB 28275. d. SSBAC 28276. 183. It is a process of combining transmissions from more than one source and transmitting them over a common facility such as metallic or optical fiber cable or a radio-frequency channel. 28277. a. buffering 28278. b. modulation 28279. c. multiplexing 28280. d. demultiplexing 28281. 184. It is an analog method of combining two or more analog sources that originally occupied the same frequency band in such a manner that the channels do not interfere with each other. 28282. a. ATM 28283. b. FDM 28284. c. TDM 28285. d. WDM 28286. 185. It is a multiplexing method that uses double-sideband suppressed-carrier transmission to combine two information sources into a single composite waveform. 28287. a. QM 28288. b. WDM 28289. c. TDM 28290. d. FDM 28291. 186. Single-sideband transmitters are rated in ______. 28292. a. rms power 28293. b. dc power 28294. c. average power 28295. d. peak envelope power 28296. 187. In an SSB transmitter, one is most likely to find a ______. 28297. a. class C audio amplifier 28298. b. tuned modulator 28299. c. class B RF amplifier 28300. d. class A RF output amplifier 28301. 188. Indicate in which one of the following only one sideband is transmitted: 28302. a. H3E 28303. b. A3E 28304. c. B8E 28305. d. C3F 28306. 189. One of the following cannot be used to remove the unwanted sideband in SSB. This is the 28307. a. filter system 28308. b. phase-shift method 28309. c. third method 28310. d. balanced modulator 28311. 190. R3E modulation is sometimes used to 28312. a. allow the receiver to have a frequency synthesizer 28313. b. simplify the frequency stability problem in reception 28314. c. reduce the power that must be transmitted 28315. d. reduce the bandwidth required for transmission 28316. 191. To provide two or more voice circuits with the same carrier, it is necessary to use 28317. a. ISB 28318. b. carrier reinsertion 28319. c. SSB with pilot carrier 28320. d. Lincomplex 28321. 192. The main advantage of SSB over standard AM or DSB is 28322. a. less spectrum is used 28323. b. simpler equipment is used 28324. c. less power is consumed 28325. d. a higher modulation percentage 28326. 193. In SSB, which sideband is the best to use? 28327. a. upper 28328. b. lower 28329. c. neither 28330. d. depends upon the use 28331. 194. The output of an SSB transmitter with a 3.85 MHz carrier and a 1.5 kHz sine wave modulating tone is 28332. a. a 3.8485 MHz sine wave 28333. b. a 3.85 MHz sine wave 28334. c. 3.85, 3.8485 and 3.8515 MHz sine waves 28335. d. 3848.5 and 3851.5 MHz sine waves 28336. 195. An SSB transmitter produces a 400 V peak to peak signal across a 52 ohm antenna load. The PEP output is 28337. a. 192.2 W 28338. b. 384.5 W 28339. c. 769.2 W 28340. d. 3077 W 28341. 196. The output power of SSB transmitter is usually expressed is terms of 28342. a. average power 28343. b. RMS power 28344. c. peak to peak power 28345. d. peak envelope power 28346. 197. An SSB transmitter has a PEP rating of 1 kilowatts. The average output power is in the range of 28347. a. 150 to 450 W 28348. b. 100 to 300 W 28349. c. 250 to 333 W 28350. d. 3 to 4 kW 28351. 198. In amplitude modulation technique, the unmodulated carrier is referred to as having___.. 28352. a. 100% modulation 28353. b. 0% modulation 28354. c. 50% modulation 28355. d. overmodulated 28356. 199. What is the process in radio communication where the information or intelligent signal is at lower frequency is put unto higher radio frequency for transmission to receiving station? 28357. a. detection 28358. b. mixing 28359. c. modulation 28360. d. demodulation 28361. 200. Which of the following signals is suppressed by balanced modulator circuit? 28362. a. 1st IF signal 28363. b. carrier signal 28364. c. harmonics 28365. d. 2nd IF signal 28366. 28367. 28368. 28369. 28370. 28371. 28372. 28373. 28374. 28375. 28376. 28377. MULTIPLE CHOICE QUESTIONS IN 28378. ANGLE MODULATION 28379. Electronics Systems and Technologies 28380. By 28381. Melvin C. Arceo 28382. 28383. 28384. 28385. 28386. 28387. 28388. 28389. 28390. 28391. 28392. ENCODED BY: 28393. SANTOLLO, Dan Alvin 28394. 1. He developed the first successful FM radio system 28395. a. B.E.Alpine 28396. b. N.S. Kapany 28397. c. E.H. Armstrong 28398. d. A.C.S. Van Heel 28399. 2. Results whenever the phase angle of sinusoidal wave is varied with respect to time 28400. a. angle modulation 28401. b. digital modulation 28402. c. amplitude modulation 28403. d. pulse modulation 28404. 3. In the spectrum of a frequency -modulated wave 28405. a. the carrier frequency disappears with a large modulation index 28406. b. the amplitude of any sideband depends on the modulation index 28407. c. the total number of sidebands depends on the modulation index 28408. d. the carrier frequency cannot disappear 28409. 4.What is the frequency swing of an FM broadcast transmitter when modulated 60% 28410. a. 60 kHz 28411. b. 45 kHz 28412. c. 30 kHz 28413. d. 25 kHz 28414. 5. Varying the frequency of a constant -amplitude carrier directly proportional to the amplitude to the modulating signal at a rate equal to the frequency of the modulating signal 28415. a. amplitude modulation 28416. b. angle modulation 28417. c. phase modulation 28418. d. frequency modulation 28419. 6. The amount of frequency deviation from the carrier center frequency in an FM transmitter is proportional to what characteristic of the frequency signal? 28420. a. amplitude 28421. b. frequency 28422. c. phase 28423. d. shape 28424. 7. It is a modulation where the angle of a wave carrier is varied from its reference value 28425. a. amplitude modulation 28426. b. angle modulation 28427. c. analog modulation 28428. d. digital modulation 28429. 8. Both FM and PM are types of what kind of modulation? 28430. a. amplitude 28431. b. phase 28432. c. angle 28433. d. duty cycle 28434. 9. Varying the phase of a constant amplitude carrier displacement proportional to the amplitude of the modulating signal at a rate equal to the frequency of the modulating signal. 28435. a. amplitude modulation 28436. b. angle modulation 28437. c. phase modulation 28438. d. frequency modulation 28439. 10. The difference between phase and frequency modulation 28440. a. is purely theoretical because they are the same in practice 28441. b. is too great to make the two systems compatible 28442. c. lies in the poorer audio responses of phase modulation 28443. d. lies in the different definitions of the modulation index 28444. 11. The relative angular displacement of the carrier phase in radians with respect to the reference phase is called ______. 28445. a. phase deviation 28446. b. carrier deviation 28447. c. frequency deviation 28448. d. information deviation 28449. 12. If the amplitude of the modulating signal decreases, the carrier deviation 28450. a. increases 28451. b. decreases 28452. c. remains constant 28453. d. goes to zero 28454. 13. On an FM signal, maximum deviation occurs at what point on the modulating signal? 28455. a. zero-crossing points 28456. b. peak positive amplitudes 28457. c. peak negative amplitude 28458. d. both peak positive and negative amplitudes 28459. 14. The amount of oscillator frequency increase and decrease around the carrier frequency is called ______. 28460. a. frequency deviation 28461. b. phase shift 28462. c. intelligence frequency 28463. d. baseband 28464. 15. The relative displacement of the carrier frequency in hertz in respect to its unmodulated value is called ______. 28465. a. frequency deviation 28466. b. phase deviation 28467. c. information deviation 28468. d. carrier deviation 28469. 16. A pre-emphasis circuit provides extra noise immunity by 28470. a. boosting the bass frequencies 28471. b. amplifying the higher audio frequencies 28472. c. preamplfying the whole audio band 28473. d. converting the phase modulation to FM 28474. 17. It is the instantaneous change in phase of the carrier at a given instant of time and indicates how much phase of the carrier is changing with respect to its reference phase. 28475. a. instantaneous frequency 28476. b. instantaneous frequency deviation 28477. c. instantaneous phase 28478. d. instantaneous phase deviation 28479. 18. Calculate the amount of frequency deviation caused by a limited noise spike that still cause an undesired phase shift of 35 degrees when the input frequency is 5kHz. 28480. a. 2.40kHz 28481. b. 3.05kHz 28482. c. 1.29kHz 28483. d. 4.45kHz 28484. 19. Which of the following determines the rate of carrier deviation? 28485. a. intelligence frequency 28486. b. frequency deviation 28487. c. carrier frequency 28488. d. broadband frequency 28489. 20. It is the precise phase of the carrier at a given instant of time 28490. a. instantaneous phase deviation 28491. b. instantaneous phase 28492. c. instantaneous frequency deviation 28493. d. instantaneous frequency 28494. 21. In PM, a frequency shift occurs while what characteristic of the modulating signal is changing? 28495. a. shape 28496. b. phase 28497. c. frequency 28498. d. amplitude 28499. 22. In FM, it is a device that in which amplitude variations are derived in response to frequency or phase variations 28500. a. detector 28501. b. discriminator 28502. c. demodulator 28503. d. receiver 28504. 23. Maximum frequency deviation of a PM signal occurs at 28505. a. zero-crossing points 28506. b. peak positive amplitudes 28507. c. peak negative amplitude 28508. d. peak positive and negative amplitude 28509. 24. Since noise phase-modulates the FM wave, as the noise sideband frequency approaches the carrier frequency, the noise amplitude 28510. a. remains constant 28511. b. is decreased 28512. c. is increased 28513. d. is equalized 28514. 25. It is the instantaneous change in frequency of the carrier and is defined as the first time derivative of the phase deviation 28515. a. instantaneous frequency 28516. b. instantaneous frequency deviation 28517. c. instantaneous phase 28518. d. instantaneous phase deviation 28519. 26. Since noise phase- modulates the FM wave, as the noise sideband frequency approaches the carrier frequency, the noise amplitude 28520. a. remains constant 28521. b. is decreased 28522. c. is increased 28523. d. is equalized 28524. 27. It is the precise frequency of the carrier at a given instant of time is defined as the first time derivative of the instantaneous phase. 28525. a. instantaneous frequency 28526. b. instantaneous frequency deviation 28527. c. instantaneous phase 28528. d. instantaneous phase deviation 28529. 28. It is the output-versus-input transfer functions for modulators which give the relationship between the output parameter changes in respect to specified changes in the input signal. 28530. a. frequency deviation 28531. b. deviation sensitivity 28532. c. transconductance curve 28533. d. phase deviation 28534. 29. When the modulating frequency is doubled, the modulation index is halved, and the modulating voltage remains constant. The modulation system is 28535. a. amplitude modulation 28536. b. phase modulation 28537. c. frequency modulation 28538. d. any of the above 28539. 30. In PM, carrier frequency deviation is not proportional to: 28540. a. modulating signal amplitude 28541. b. carrier amplitude and frequency 28542. c. modulating signal frequency 28543. d. modulator phase shift 28544. 31. To compensate for increases in carrier frequency deviation with an increase in modulating signal frequency, what circuit is used between the modulating signal and phase modulator? 28545. a. low-pass filter 28546. b. high-pass filter 28547. c. phase shifter 28548. d. bandpass filter 28549. 32. Indicate which one of the following is not an advantage of PM over AM: 28550. a. better noise immunity is provided 28551. b. lower bandwidth is required 28552. c. the transmitted power is more useful 28553. d. less modulating power is required 28554. 33. With phase modulation, the maximum frequency deviation occurs during what value of the modulating signal? 28555. a. positve peak value 28556. b. rms value 28557. c. negative peak value 28558. d. zero crossings 28559. 34. With frequency modulation, maximum frequency deviation occurs _____ of the modulation signal. 28560. a. positive peak value 28561. b. both positive and negative peak value 28562. c. negative peak value 28563. d. zero crossings 28564. 36. With phase modulation, peak phase deviation is called ______. 28565. a. modulation index 28566. b. frequency deviation 28567. c. phase deviation 28568. d. instantaneous phase 28569. 37. The FM produced by PM is called 28570. a. FM 28571. b. PM 28572. c. indirect FM 28573. d. indirect PM 28574. 38. In a broadcast superheterodyne receiver, the 28575. a. local oscillator operates below the signal frequency 28576. b. mixer input must be tuned to the signal frequency 28577. c. local oscillator frequency is normally double the OF 28578. d. RF amplifier normally works at 455kHz above the carrier frequency 28579. 39. If the amplitude of the modulating signal applied to a phase modulator is constant, the output signal will be 28580. a. zero 28581. b. the carrier frequency 28582. c. above the carrier frequency 28583. d. below the carrier frequency 28584. 40. To prevent overloading of the last IF amplifier in the receiver, one should use the 28585. a. squelch 28586. b. variable sensitiivity 28587. c. variable selectivity 28588. d. double conversion 28589. 41. The peak-to-peak frequency deviation is sometimes called ______. 28590. a. phase deviation 28591. b. peak phase deviation 28592. c. carrier swing 28593. d. instantaneous frequency 28594. 42. A 100MHz carrier is deviated 50 kHz by 4kHz signal. The modulation index is 28595. a. 5 28596. b. 8 28597. c. 12.5 28598. d. 20 28599. 43. With angle modulation, it is defined as the ratio of the frequency deviation actually produced to the maximum frequency deviation allowed by law stated in percent form. 28600. a. modulation index 28601. b. percent modulation 28602. c. frequency deviation 28603. d. phase deviation 28604. 44. In a broadcast FM system, the input S/N = 4. Calculate the worst case S/N at the output if the receiver's internal noise effect is negligible. 28605. a. 19.8:1 28606. b. 21.6:1 28607. c. 23:1 28608. d. 15:1 28609. 45. It is a circuit in which the carrier is varied in such a way that its instantaneous phase is proportional to the modulating signal. 28610. a. frequency modulators 28611. b. amplitude modulators 28612. c. phase modulators 28613. d. mixers 28614. 46. In a ratio detector 28615. a. the linearity is worse than in a phase discriminator 28616. b. stabilization against signal strength variations is provided 28617. c. the output is twice that obtainable from the similar phase discriminator 28618. d. the circuit is the same as in a discriminator, except that the diodes are reversed 28619. 47. The maximum deviation of an FM carrier is 2kHz by a maximum modulating signal of 400Hz. The deviation ratio is 28620. a. 0.2 28621. b. 5 28622. c. 8 28623. d. 40 28624. 48. The unmodulated carrier is a single-frequency sinusoid commonly called ______. 28625. a. unrest frequency 28626. b. rest frequency 28627. c. frequency-modulated frequency 28628. d. carrier frequency 28629. 49. It is a circuit in which the carrier is varied in such a way that its instantaneous phase is proportional to the integral of the modulating signal 28630. a. phase modulator 28631. b. phase deviator 28632. c. amplitude deviator 28633. d. frequency modulator 28634. 50. The typical squelch circuit 28635. a. cuts off an audio amplifier when the carrier is absent 28636. b. eliminates the RF interference when the signal is weak 28637. c. cuts off an IF amplifier when the AGC is maximum 28638. d. cuts off an IF amplifier when the AGC is minimum 28639. 51. Frequency modulators are also known as ______. 28640. a. phase deviators 28641. b. frequency deviators 28642. c. phase modulators 28643. d. amplitude deviators 28644. 52. A 70 kHz carrier has a frequency deviation of 4 kHz with a 1000Hz signal. What is the bandwidth of the FM signal? 28645. a. 4kHz 28646. b. 7kHz 28647. c. 10 kHz 28648. d. 28 kHz 28649. 53. The controlled oscillator synthesizer is sometimes preferred to the direct one because 28650. a. it is simpler piece of equipment 28651. b. its frequency stability is better 28652. c. it does not require crystal oscillators 28653. d. it is relatively free of spurious frequencies 28654. 54. A system with a differentiator followed by an FM modulator is called 28655. a. PM modulator 28656. b. FM modulator 28657. c. PM demodulator 28658. d. FM demodulator 28659. 55. The image frequency of a superheterodyne receiver 28660. a. is created within the receiver itself 28661. b. is due to insufficient adjacent channel rejection 28662. c. is not rejected by the IF tuned circuits 28663. d. is independent of the frequency to which the receiver is tuned 28664. 56. A system with FM demodulator followed by an integrator 28665. a. PM modulator 28666. b. PM demodulator 28667. c. FM modulator 28668. d. FM demodulator 28669. 57. A system with an integrator followed by a PM modulator 28670. a. PM modulator 28671. b. FM modulator 28672. c. PM demodulator 28673. d. FM demodulator 28674. 58. An FM transmitter has a maximum deviation of 12kHz and a maximum modulating frequency of 12 kHz. The bandwidth by Carson's rule is 28675. a. 24kHz 28676. b. 33.6kHz 28677. c. 38.8kHz 28678. d. 48kHz 28679. 59. A system with PM demodulator followed by a differentiator 28680. a. PM modulator 28681. b. FM modulator 28682. c. PM demodulator 28683. d. FM demodulator 28684. 60. A receiver has poor IF selectivity. It will therefore also have poor 28685. a. blocking 28686. b. double-spotting 28687. c. diversity reception 28688. d. sensitivity 28689. 61. Three point tracking is achieved with 28690. a. variable selectivity 28691. b. the padder capacitor 28692. c. double spotting 28693. d. double conversion 28694. 62. He mathematically proved that for a given modulating signal frequency a frequency-modulated wave cannot be accommodated in a narrower bandwidth than an amplitude modulated wave. 28695. a. R.C. Alpine 28696. b. E.H. Armstrong 28697. c. J.R. Carson 28698. d. J.J. Thomson 28699. 63. The maximum allowed deviation of the FM sound signal in TV is 25 kHz. If the actual deviation is 18kHz, the percent modulation is 28700. a. 43 percent 28701. b. 72 percent 28702. c. 96 percent 28703. d. 139 percent 28704. 64. The local oscillator of a broadcast receiver is tuned to a frequency higher than the incoming frequency 28705. a. to help the image frequency rejection 28706. b. to permit easier tracking 28707. c. because otherwise an intermediate frequency could not be produced 28708. d. to allow adequate frequency coverage without switching 28709. 65. Which of the following is not a major benefit of FM over AM? 28710. a. greater efficiency 28711. b. noise immunity 28712. c. capture effect 28713. d. lower complexity and cost 28714. 66. Low-index FM systems are also known as ______. 28715. a. wideband FM 28716. b. narrowband FM 28717. c. commercial FM 28718. d. medium FM 28719. 67. For high-index signal, a method of determining the bandwidth is called ______approach 28720. a. quasi-stationary 28721. b. quasi-movement 28722. c. quasi-deviation 28723. d. any of these 28724. 68. When a receiver has a good blocking performance, this means that 28725. a. it does not suffer from double-spotting 28726. b. its image frequency rejection is poor 28727. c. it is unaffected by AGC derived from a nearby transmission 28728. d. its detector suffers from burnout 28729. 69. He established a general rule to estimate the bandwidth for all angle- modulated system regardless of the modulation index. 28730. a. R.C. Alpine 28731. b. E.H. Armstrong 28732. c. J.R. Carson 28733. d. J.J. Thomson 28734. 70. An AM receiver uses a diode detector for demodulation. This enables it satisfactority to receive 28735. a. single-sideband, suppressed carrier 28736. b. single-sideband, reduced carrier 28737. c. independent sideband 28738. d. single-sideband, full carrier 28739. 71. The primary disadvantage of FM is its 28740. a. higher cost and complexity 28741. b. excessive use of spectrum space 28742. c. noise susceptibility 28743. d. lower efficiency 28744. 72. A rule that approximates the bandwidth necessary to transmit an angle- modulated wave as twice the sum of the peak frequency deviation and the highest modulating frequency. 28745. a. Carson's rule 28746. b. Shannon's rule 28747. c. Hartley's law 28748. d. Hartley-Shannon law 28749. 73. It is the worst case modulation index and is equal to the maximum peak frequency deviation divided by the maximum modulating signal frequency 28750. a. peak phase deviation 28751. b. frequency deviation 28752. c. deviation ratio 28753. d. signal to noise ratio 28754. 74. The receiver circuit that rids FM noise is the 28755. a. modulator 28756. b. demodulator 28757. c. limiter 28758. d. low-pass filter 28759. 75. The phenomenon of a strong FM signal dominating a weaker signal on a common frequency is referred to as the 28760. a. capture effect 28761. b. blot out 28762. c. quieting factor 28763. d. domination syndrome 28764. 76. The highest side frequencies form one channel are allowed to spill over into adjacent channels producing an interference known as ______. 28765. a. co-channel interference 28766. b. adjacent channel interference 28767. c. splatter 28768. d. overmodulation 28769. 77. A pre-emphasis is usually a ______. 28770. a. high-pass filter 28771. b. band-stop filter 28772. c. low-pass filter 28773. d. bandpass filter 28774. 78. Frequency modulation transmitters are more efficient because their power is increased by what type of amplifier? 28775. a. class A 28776. b. class B 28777. c. class C 28778. d. all of the above 28779. 79. Noise interferes mainly with modulating signals that are 28780. a. sinusoidal 28781. b. non-sinusoidal 28782. c. low frequencies 28783. d. high frequencies 28784. 80. A de-emphasis is usually a ______. 28785. a. high pass filter 28786. b. band-stop filter 28787. c. low-pass filter 28788. d. bandpass filter 28789. 81. A pre-emphasis is a ______. 28790. a. integrator 28791. b. differentiator 28792. c. either integrator or differentiator 28793. d. neither integrator or differentiator 28794. 82. A de-emphasis is a ______. 28795. a. integrator 28796. b. differentiator 28797. c. either integrator or differentiator 28798. d. neither integrator or differentiator 28799. 83. Pre-emphasis circuit boost what modulating frequencies before modulation? 28800. a. high frequencies 28801. b. mid-range frequencies 28802. c. low frequencies 28803. d. all of the above 28804. 84. The primary disadvantage of direct PM 28805. a. relatively unstable LC oscillators must be used to produce carrier frequency which prohibits using crystal oscillators 28806. b. relatively high frequency deviations and modulation indices are easily obtained due to the fact that the oscillators are inherently unstable. 28807. c. crystal oscillators are inhrently stable and therefore more difficult for them to achieve high phase deviations and modulation indices 28808. d. carrier oscillator is isolated form the actual modulator circuit and therefore can be stable source. 28809. 85. It is an angle modulation in which the frequency of the carrier is deviated by the modulating signal 28810. a. direct PM 28811. b. PM 28812. c. indirect FM 28813. d. any of these 28814. 86. One of the following is a method of performing frequency up conversion 28815. a. heterodyning 28816. b. amplification 28817. c. modulation 28818. d. none of these 28819. 87. A pre-emphasis circuit is a 28820. a. low-pass filter 28821. b. high-pass filter 28822. c. phase shifter 28823. d. bandpass filter 28824. 88. Pre emphasis is compensated for the receiver by a 28825. a. phase inverter 28826. b. bandpass filter 28827. c. high-pass filter 28828. d. low-pass filter 28829. 89. A circuit that compares the frequency of the noncrystal carrier oscillator to a crystal reference oscillator and then produces a correction voltage proportional to the difference between the two frequencies 28830. a. AFC 28831. b. squelch circuit 28832. c. AGC 28833. d. heterodyning circuit 28834. 90. A frequency selective device whose output voltage is proportional to the difference between the input frequency and its resonant frequency 28835. a. modulator 28836. b. squelch circuit 28837. c. frequency discriminator 28838. d. FM transmitters 28839. 91. Allows FM receiver to differentiate between two signals received with the same frequency but different amplitudes 28840. a. flywheel effect 28841. b. amplitude limiting 28842. c. noise immunity 28843. d. capture effect 28844. 92. If an FM transmitter employs one doubler, one tripler, and one quadrupler, what is the carrier frequency swing when the oscillator frequency swing is 2kHz? 28845. a. 24 kHz 28846. b. 48 kHz 28847. c. 14 kHz 28848. d. 12 kHz 28849. 93. The cut-off frequency of pre-emphasis and de-emphasis circuits is 28850. a. 1 kHz 28851. b. 2.122 kHz 28852. c. 5 kHz 28853. d. 75 kHz 28854. 94. Which of the following is not a disadvantage of angle modulation? 28855. a. wide bandwidth 28856. b. complex 28857. c. high cost 28858. d. less noise 28859. 95. In FM receivers, which of the following rejects the image frequency? 28860. a. preselector 28861. b. detector 28862. c. IF amplifier 28863. d. mixer 28864. 96. In FM receivers, which of the following provides most gain and selectivity of the receiver? 28865. a. detector 28866. b. RF amplifier 28867. c. local oscillator 28868. d. IF amplifier 28869. 97. Another name for Voltage Variable Capacitor is 28870. a. PIN diode 28871. b. varactor diode 28872. c. snap diode 28873. d. hot carrier diode 28874. 98. The depletion region in a junction diode forms what part of a capacitor? 28875. a. plates 28876. b. leads 28877. c. package 28878. d. dielectric 28879. 99. Which of the following removes the information from the modulated wave in FM receivers? 28880. a. amplifiers 28881. b. mixer 28882. c. speakers 28883. d. discriminator 28884. 100. The final IF amplifier in FM receivers is sometimes called ______. 28885. a. tuned amplifier 28886. b. limiter 28887. c. passband filter 28888. d. any of these 28889. 101. ______are frequency-dependent circuits designed to produce an output voltage that is proportional to the instantaneous frequency at its output 28890. a. PM receivers 28891. b. PM demodulators 28892. c. FM demodulators 28893. d. FM receivers 28894. 102. Increasing the reverse bias on a varactor diode will it cause its capacitance to 28895. a. decrease 28896. b. increase 28897. c. remains the same 28898. d. drop to zero 28899. 103. The capacitance of a varactor diode is in what general range? 28900. a. pF 28901. b. nF 28902. c. uF 28903. d. F 28904. 104. Which of the following is the simplest form of tuned-circuit frequency discriminator? 28905. a. Foster-Seeley discriminator 28906. b. Ratio detector 28907. c. slope detector 28908. d. PLL detector 28909. 105. It is simply two single-ended slope detectors connected in parallel and fed 180 degrees out phase. 28910. a. Foster-Seeley discriminator 28911. b. quadrature detector 28912. c. balanced slope generator 28913. d. PLL detector 28914. 106. The frequency change in crystal oscillator produced by a varactor diode is 28915. a. zero 28916. b. small 28917. c. medium 28918. d. large 28919. 107. A phase modulator varies the phase shift of the 28920. a. carrier 28921. b. modulating signal 28922. c. modulating voltage 28923. d. sideband frequency 28924. 108. Which of the following tuned-circuit frequency discriminator is relatively immune to amplitude variations in its input signal? 28925. a. ratio detector 28926. b. slope detector 28927. c. balanced slope detector 28928. d. quadrature detector 28929. 109. In FM demodulators, it is also called coincidence detector 28930. a. quadrature demodulator 28931. b. PLL demodulator 28932. c. Foster-Seely discriminator 28933. d. ratio detector 28934. 110. The widest phase variation is obtained with ______. 28935. a. RC low-pass filter 28936. b. RC high-pass filter 28937. c. LR low-pass filter 28938. d. LC resonant circuit 28939. 111. An FM receiver provides 100dB of voltage gain prior to the limiter. Calculate the receiver's sensitivity if the limiter's quieting for an FM receiver is 300mV? 28940. a. 4.5 uV 28941. b. 3.0 uV 28942. c. 2.1 uV 28943. d. 1.3 uV 28944. 112. The small frequency change produced by a phase modulator can be increased by using ______. 28945. a. amplifier 28946. b. mixer 28947. c. frequency multiplier 28948. d. frequency divider 28949. 113. In FM receiver, limiters produce a constant-amplitude output of all signals above a prescribed minimum input level called ______. 28950. a. threshold voltage 28951. b. capture level 28952. c. quieting level 28953. d. any of these 28954. 114. The inherent ability of FM to diminish the effects of interfering signals is called ______. 28955. a. capture effect 28956. b. noise suppression 28957. c. adjacent channel rejection 28958. 115. A crystal oscillator whose frequency can be changed by an input voltage is called ______. 28959. a. VCO 28960. b. VXO 28961. c. VFO 28962. d. VHF 28963. 116. Which oscillators are preferred for carrier generators because of their good frequency stability? 28964. a. LC 28965. b. RC 28966. c. LR 28967. d. crystal 28968. 117. Which of the following frequency demodulators requires an input limiter? 28969. a. Foster-Seely discriminator 28970. b. Pulse-averaging discriminator 28971. c. quadrature detector 28972. d. PLL 28973. 118. Provides a slight automatic control over the local oscillator circuit and compensates for its drift that would otherwise cause a station to become detuned. 28974. a. AGC 28975. b. AFC 28976. c. VVC 28977. d. VCO 28978. 119. ______of an FM receiver is the maximum dB difference signal strength between two received signals necessary for the capture effect to suppress the weaker signal. 28979. a. capture effect 28980. b. capture gain 28981. c. capture ratio 28982. d. capture loss 28983. 120. When two limiter stages are used, there is called ______. 28984. a. double limiting 28985. b. two-time limiting 28986. c. reserve limiting 28987. d. ratio limiting 28988. 121. Which discriminator averages pulses in a low-pass filter? 28989. a. ratio detector 28990. b. PLL 28991. c. quadrature detector 28992. d. pulse-averaging discriminator 28993. 122. Which of the frequency demodulator is considered the best overall? 28994. a. ratio detector 28995. b. PLL 28996. c. quadrature 28997. d. pulse-averaging discriminator 28998. 123. One of the prominent advantage of FM over PM is 28999. a. FM requires frequency multipliers to increase the modulation index and frequency deviation to useful levels 29000. b. the voltage controlled oscillators of FM can be directly modulated and produce outputs with high frequency deviations and high modulation 29001. c. the modulation index of FM is independent of the modulating signal frequency 29002. d. FM offers better signal-to-noise performance than PM 29003. 124. What special speaker is used for low frequency? 29004. a. baffle 29005. b. base 29006. c. tweeter 29007. d. woofer 29008. 125. Each speaker assembly at the receiver reproduces exactly the same information 29009. a. monophonic 29010. b. multiphonic 29011. c. stereophonic 29012. d. any of these 29013. 126. In a pulse averaging discriminator, the pulse are produced by a(n) 29014. a. astable multivibrator 29015. b. zero-crossing detector 29016. c. one-shot 29017. d. low-pass filter 29018. 127. A reactance modulator looks like a capacitance of 35pF in parallel with the oscillator-tuned circuit whose inductance is 50 uH and capacitance is 40 pF. What is the center frequency of the oscillator prior to FM? 29019. a. 1.43 MHz 29020. b. 2.6 MHz 29021. c. 3.56 MHz 29022. d. 3.8 MHz 29023. 128. The frequency of an SCA channel subcarrier is ______. 29024. a. 38 kHz 29025. b. 15 kHz 29026. c. 67 kHz 29027. d. 53 kHz 29028. 129. The L-R stereo channel in FM broadcasting is between 29029. a. 50 Hz to 15 kHz 29030. b. 60 kHz to 74 kHz 29031. c. 23 kHz to 53 kHz 29032. d. 20 Hz to 20 kHz 29033. 130. An FM demodulator that uses a differential amplifier and tuned circuits to convert frequency variations into voltage variations is the 29034. a. quadrature detector 29035. b. Foster-Seeley discriminator 29036. c. differential peak detector 29037. d. phase-locked loop 29038. 131. The output amplitude of the phase detector in a quadrature detector is proportional to 29039. a. pulse width 29040. b. pulse frequency 29041. c. input amplitude 29042. d. the phase shift value at center 29043. 132. The output to a PLL is 2MHz. In order for the PLL to be locked. The VCO output must be 29044. a. 0 MHz 29045. b. 1 MHz 29046. c. 2 MHz 29047. d. 4 MHz 29048. 133. With stereo transmission, the maximum frequency deviation is 29049. a. 75 kHz 29050. b. 15 kHz 29051. c. 25 kHz 29052. d. 3 kHz 29053. 134. The L + R stereo channel occupies ______. 29054. a. 50 Hz to 15 kHz 29055. b. 60 kHz to 74 kHz 29056. c. 23 kHz to 53 kHz 29057. d. 20 Hz to 20 kHz 29058. 135. The band of frequencies over which a PLL will acquire or recognize an input signal is called the 29059. a. circuit bandwidth 29060. b. capture range 29061. c. band of acceptance 29062. d. lock range 29063. 136. The three primary frequency bands are allocated by FCC for two-way FM radio communications except: 29064. a. 132 MHz to 174 MHz 29065. b. 450 MHz to 470 MHz 29066. c. 806 MHz to 947 MHz 29067. d. 1026 MHz to 1035 MHz 29068. 137. The maximum frequency deviation for two-way transmitters is typically 29069. a. 25 kHz 29070. b. 5 kHz 29071. c. 75 kHz 29072. d. 3 kHz 29073. 138. Decreasing the input frequency to be locked PLL will cause the VCO output to 29074. a. decrease 29075. b. increase 29076. c. remains constant 29077. d. jump to the free-running frequency 29078. 139. The range of frequencies over which a PLL will track input signal variations is known as the 29079. a. circuit bandwidth 29080. b. capture range 29081. c. band of acceptance 29082. d. lock range 29083. 140. The maximum modulating signal frequency for two-way transmitter is typically 29084. a. 3 kHz 29085. b. 5 kHz 29086. c. 15 kHz 29087. d. 75 kHz 29088. 141. Over a narrow range of frequencies, the PLL acts like a 29089. a. low-pass filter 29090. b. bandpass filter 29091. c. tunable oscillator 29092. d. frequency modulator 29093. 142. The output of a PLL frequency demodulator is taken from the 29094. a. low-pass filter 29095. b. VCO 29096. c. phase detector 29097. d. none of these 29098. 143. The primary advantage of FM over AM 29099. a. capture effect 29100. b. noise immunity 29101. c. FM can use class C amplifiers 29102. d. FM is more efficient 29103. 144. The usual cutoff frequency of pre-emphasis and de-emphasis in broadcast FM? 29104. a. 50 Hz 29105. b. 75 Hz 29106. c. 2122 Hz 29107. d. 3183 Hz 29108. 145. The maximum deviation for narrowband FM? 29109. a. 2500 29110. b. 5 29111. c. 1.67 29112. d. 75 29113. 146. Which of the following is best frequency demodulator in use? 29114. a. Foster-Seeley discriminator 29115. b. ratio detector 29116. c. slope detector 29117. d. PLL 29118. 147. The range of frequencies over which the PLL will capture an input signal is known as ______. 29119. a. lock range 29120. b. capture range 29121. c. bandwidth 29122. d. sidebands 29123. 148. Type of FM demodulator that is widely used in TV audio demodulators 29124. a. ratio detector 29125. b. quadrature detector 29126. c. PLL 29127. d. pulse-averaging discriminator 29128. 149. A variation of Foster-Seeley discriminator widely used in oldr TV receiver designs 29129. a. ratio detector 29130. b. PLL 29131. c. quadrature detector 29132. d. crosby modulator 29133. 150. The range of frequencies over which a PLL will track an input is called 29134. a. lock range 29135. b. capture range 29136. c. track range 29137. d. driving range 29138. 151. What is the maximum deviation for monoaural TV sound 29139. a. 25 kHz 29140. b. 75 kHz 29141. c. 50 kHz 29142. d. 125 kHz 29143. 152. What is the maximum deviation for stereo TV sound? 29144. a. 25 kHz 29145. b. 75 kHz 29146. c. 50 kHz 29147. d. 125 kHz 29148. 153. In FM stereo broadcasting, the L + R signal 29149. a. double-sideband modulates a subcarrier 29150. b. modulates the FM carrier 29151. c. frequency modulates a subcarrier 29152. d. is not transmitted 29153. 154. In FM stereo broadcasting, the L - R signal 29154. a. double-sideband modulates a subcarrier 29155. b. modulates the FM carrier 29156. c. frequency modulates a subcarrier 29157. 155. The SCA signal if used in FM broadcasting is transmitted via 29158. a. a 19 kHz subcarrier 29159. b. a 38 kHz subcarrier 29160. c. a 67 kHz subcarrier 29161. d. the main FM carrier 29162. 156. Which of the following is considered as an indirect method of generating FM? 29163. a. reactance modulator 29164. b. balanced modulator 29165. c. varactor diode modulation 29166. d. armstrong system 29167. 157. In an FM system, if the modulation index is doubled by halving the modulating frequency, what will be the effect on the maximum deviation? 29168. a. remains the same 29169. b. doubles 29170. c. decrease by 1/2 29171. d. increase by 1/4 29172. 158. Determine from the following the common use of DSB in broadcast and telecommunication. 29173. a. satellite communications 29174. b. FM/TV stereo 29175. c. two-way communications 29176. d. telephone systems 29177. 159. Phase modulation emission type 29178. a. F3F 29179. b. G3E 29180. c. F3E 29181. d. F3C 29182. 160. The range of frequencies over which a PLL will cause the input of the VCO signals to remain synchronized is known as the ______range. 29183. a. capture 29184. b. lock 29185. c. acquisition 29186. d. any of these 29187. 161. If the PLL input is zero, the VCO will operate at its ______frequency. 29188. a. free-running 29189. b. natural 29190. c. operating 29191. d. any of these 29192. 162. Since a PLL will only respond to signals over a narrow frequency range, it acts likes a ______. 29193. a. low-pass filter 29194. b. high-pass filter 29195. c. bandpass filter 29196. d. bandstop filter 29197. 163. In a PLL demodulating an FM signal, the VCO output is an exact reproduction of the ______. 29198. a. modulating signal 29199. b. carrier signal 29200. c. carrier amplitude 29201. d. VCO output 29202. 164. In a PLL demodulating an FM signal, the VCO output is an exact reproduction of the ______. 29203. a. FM input 29204. b. VCO input 29205. c. modulating signal 29206. d. error signal 29207. 165. After the IF stages have been aligned, the next state to align in FM receiver is 29208. a. local oscillator 29209. b. limiter stage 29210. c. RF amplifier 29211. d. mixer stage 29212. 166. The modulation system used for telegraphy is 29213. a. frequency-shift keying 29214. b. two-tone modulation 29215. c. purse-code modulation 29216. d. single-tone modulation 29217. 167. What is emission F3F? 29218. a. Facsimile 29219. b. RTTY 29220. c. modulated CW 29221. d. television 29222. 168. What is a frequency discriminator? 29223. a. a circuit for filtering two closely adjacent signals 29224. b. a circuit for detecting FM signals 29225. c. an FM generator 29226. d. an automatic bandswitching circuit 29227. 169. Type of radio communication transmission utilizing frequency modulation technique 29228. a. television video 29229. b. broadcasting in 535-1606 kHz 29230. c. single sideband HF transmission 29231. d. television audio 29232. 170. Why was FM first developed? 29233. a. to compete with AM 29234. b. to overcome noise 29235. c. to increase listeners 29236. d. to supplement AM 29237. 171. To what feature of the modulating tone is FM deviation proportional? 29238. a. amplitude 29239. b. frequency 29240. c. phase 29241. d. phase shift 29242. 172. Which of the following is not a basic filed of FM? 29243. a. broadcast 29244. b. TV video 29245. c. mobile communications 29246. d. amateur radio 29247. 173. Under what condition would a 1 kHz AF signal produce a single pair of FM sidebands? 29248. a. wideband 29249. b. broadcast FM 29250. c. TV audio FM 29251. d. narrowband FM 29252. 174. What deviation is considered 100% for FM broadcast stations? 29253. a. 75 kHz 29254. b. 220 kHz 29255. c. 270 kHz 29256. d. 75 kHz or 220 kHz 29257. 175. In FM broadcasting, what is the highest required modulating frequency? 29258. a. 75 kHz 29259. b. 50 kHz 29260. c. 25 kHz 29261. d. 15 kHz 29262. 176. In FM broadcasting, what is the lowest required modulating frequency? 29263. a. 50 Hz 29264. b. 30 Hz 29265. c. 10 Hz 29266. d. 5 Hz 29267. 177. What is the disadvantage of slope detection of FM> 29268. a. no discrimination against noise 29269. b. less AF distortion 29270. c. less AF out 29271. d. no filtering of carrier 29272. 178. What is the unction of the dc that comes out of the dc amplifier in a PLL- type FM detector? 29273. a. carrier signal 29274. b. filter signal 29275. c. error signal 29276. d. phase signal 29277. 179. What is the function of the dc that comes out of the dc amplifier in a PLL- type FM detector? 29278. a. oscillators 29279. b. AF signal 29280. c. RF signal 29281. d. carrier signal 29282. 180. Why should discriminators be tuned for a straight characteristic S-curve? 29283. a. less AF distortion 29284. b. greater AF out 29285. c. less RF out 29286. d. less RF distortion 29287. 181. What band for high-Q coils be more desirable for stagger-tuned-type discriminator transformer? 29288. a. wide 29289. b. intermediate 29290. c. interfacing 29291. d. narrow 29292. 182. In a Foster-Seeley circuit, the AF output voltage is ______. 29293. a. varying DC 29294. b. varying AC 29295. c. steady DC 29296. d. steady AC 183. In a stagger-tuned discriminator, the AF output voltage is ______. 29297. a. varying DC 29298. b. varying AC 29299. c. steady DC 29300. d. steady AC 29301. 184. In a ratio detector, the AF output voltage is 29302. a. steady AC 29303. b. varying AC 29304. c. steady DC 29305. d. varying DC 29306. 185. In a gated-beam detector, the AF output voltage is ______. 29307. a. steady DC 29308. b. varying AC 29309. c. varying DC 29310. d. steady AC 29311. 186. Which of the following discriminator circuits require limiters ahead of them? 29312. a. quadrature detector 29313. b. foster-seeley discriminator 29314. c. slope detector 29315. d. stagger-tuned 29316. 187. Which of the following discriminator circuits provide an automatic gain control voltage? 29317. a. ratio detector 29318. b. balanced slope detector 29319. c. quadrature detector 29320. d. stagger-tuned detector 29321. 188. Which of the following discriminator circuits has its diodes in series? 29322. a. ratio 29323. b. quadrature detector 29324. c. round-travis detector 29325. d. slope detector 29326. 189. To what frequency must the gated-beam quadrature circuit be tuned in a TV receiver? 29327. a. 10.7 MHz 29328. b. 455 kHz 29329. c. 70 MHz 29330. d. 4.5 MHz 29331. 190. To what frequency must the gated-beam quadrature circuit be tuned in an FM broadcast receiver? 29332. a. 4.3 MHz 29333. b. 10.7 MHz 29334. c. 11 MHz 29335. d. 4.8 MHz 29336. 192. With what FM detectors would AGC be an advantage? 29337. a. foster-seeley detector 29338. b. ratio detector 29339. c. quadrature detector 29340. d. phase-locked loop 29341. 193. What is the reason for using pre-emphasis? 29342. a. increase amplitude 29343. b. reduce carrier shift 29344. c. amplify RF signal 29345. d. reduce noise reception 29346. 194. What are the two types of stages in an FM receiver that differ from those in an AM receiver? 29347. a. limiting IF and detectors 29348. b. oscillators and IF amplifiers 29349. c. mixers and RF amplifiers 29350. d. local oscillators and mixers 29351. 195. What special circuits are used in a squelch system that can follow changing noise levels? 29352. a. noise amplifiers 29353. b. rectifier 29354. c. dc amplifier 29355. d. any of these 29356. 196. Why might FM be better than AM for mobile ______. 29357. a. better coverage 29358. b. not affected by solar cycles 29359. c. reduce flutter 29360. d. not absorbed by ionosphere 29361. 197. What is the order of circuit alignment in an FM receiver? 29362. a. discriminator, limiters, IF, mixer and RF 29363. b. RF, limiters, IF, mixer and discriminator 29364. c. limiters, mixer, RF, discriminator and IF 29365. d. RF, mixer, RF, IF, limiters and discriminator 29366. 198. What is the another name for the reactance-tube modualtor? 29367. a. Crosby 29368. b. Foster-Seeley 29369. c. Round Travis 29370. d. Messier 29371. 199. What effect would be produced if a small inductance were used in plasce of the 50 pF capacitance in the reactance-tube modulator? 29372. a. the circuit becomes resistive 29373. b. reactance modulator looks like an inductive circuit 29374. c. reactance modulator looks like Xc 29375. d. any of these 29376. 200. The following are significant circuits in the AFC system except: 29377. a. crystal 29378. b. mixer 29379. c. IF 29380. d. filter 29381. 201. Besides the reactance-tube modulator, what is another method of producing direct FM? 29382. a. armstrong modulator 29383. b. voltage variable capacitor 29384. c. impeadance modulator 29385. d. slug indicator 29386. 202. What is the advantage of PM? 29387. a. can use crystal oscillator 29388. b. uses more multistage 29389. c. less selective fading 29390. d. simplicity 29391. 203. What was the first broadcast FM system called? 29392. a. Arc transmitter 29393. b. MOPA 29394. c. Armstrong 29395. d. crystal 29396. 204. Why are limtiers used in FM transmitters? 29397. a. any of these 29398. b. clip noise peaks 29399. c. prevent overdrive of discriminators 29400. d. prevent overdeviation 29401. 205. Why are limiters used in FM receivers? 29402. a. provide better noise performance 29403. b. clip noise peaks 29404. c. prevent overdrive of discriminators 29405. d. any of these 29406. 206. What signals might feed into an FM broadcast station audio control console? 29407. a. microphones 29408. b. turntables 29409. c. remote lines 29410. d. any of these 29411. 29412. 29413. 29414. 29415.

29416.

29417.

29418.