DOCSLIB.ORG

AM Radio Receiver (Part II) ENGN/PHYS 207—Fall 2019

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Assignment # 5: Escape from the Deserted Island AM radio receiver (part II) ENGN/PHYS 207|Fall 2019 Figure 1: Escape the deserted island. Build an AM radio to receive AM radio transmissions from your rescue crew! Image credit: 30seconds.com Circuits You'll Build • AM radio receiver: tuner + demodulator. The main objective of this lab is to complete the design, construction, and proof-of-concept testing of your very own person AM radio receiver. You'll turn your radio into a message that holds the key to your being rescued from being marooned on a distant, deserted island. Skills and Concepts You'll Learn • Construction of capacitors and inductors • RC low pass filter (smoother) • Diodes as rectifiers • Amplifiers (voltage gain!): Become acquainted with wiring op-amp circuits. 1 1 Tuning Circuit: LC resonance The objective of this assignment is to build a full, working AM radio receiver|a real working radio to tune into music, talk shows, sports, etc! This Circuit journey begins back at Lab 4. Complete section 4 of Lab 4 (if you haven't already), in which you build, test, analyze the tuner of the AM radio. The tuner section allows you to listen into one specific radio station. Once that is complete, time to build the demodulator! 2 AM radio receiver: Demodulation Figure 2: Principle of Amplitude Modulated radio transmission. The amplitude of the carrier wave is modulated according to the audio signal envelope. Image credit: Horowitz and Hill. The Art of Electronics, 3rd ed. As we've discussed in class, Amplitude Modulated radio transmission works by forming an audio frequency envelope around the AM carrier wave (Figure 2). Watch this excellent explanation of quick AM radio theory of operation. The fundamental job of the AM demodulator circuitry is to recover the audio frequency waveform (thick trace in Figure 2 from the AM signal (\modulated radiofrequency carrier" in Figure 2). The carrier wave frequency for the AM band in the United States spans 560 kHz to 1.2 MHz. These are high frequency oscillations compared to audio content concentrated frequency band of 20 Hz - 5 kHz (bass to treble). The higher the ratio of the carrier frequency to the audio content, the more precisely the audio encoding will be. 2 Figure 3: Block diagram of the AM radio receiver. In brief, we tune into a certain AM station (1), amplify the signal (2), recover the audio waveform (3), and plug into an audio amplifier/speaker (4) 3 AM Radio System Overview Before plunging ahead, let's check out Figure 3, which shows a block diagram of an AM radio receiver. This is the 30,000 ft overview of the system. There 4 functional block indicated: 1. LC resonator: tunes into a specific station. It selects one station's AM frequency to listen to. 2. Carrier Wave Amplifier: provides voltage gain to boosts the amplitude of the original signal. 3. Diode rectifier + RC smoother: recovers the audio waveform. Rectifier grabs the positive swings in oscillation, RC smoother mathematically approximates the AM envelope. 4. Buffer Amplifier : allows us to connect audio playback device (speaker) downstream without affecting the circuit upstream. 4 Amplify the AM carrier wave We'll study amplifiers more formally in the coming weeks. Spoiler alert: They are used to amplify small signals to have an amplitude that is larger and easier to use. For instance, say the incoming radio wave has an amplitude of 100 mV = 0.1 V. And let's say we want to amplify that wave to an amplitude of 3V. Then we need an amplifier with a voltage gain of 3V/0.1V = 30. Easily done with an op-amp! 4.1 Op-amps: what's inside the proverbial black box First let's take a quick look at op-amps in practice. Study Figure 4. The 8 electrical contacts extending out of the integrated circuit (IC). They offer easy connections two separate amplifiers, labeled \1" and \2" accordingly. The amplifier is an active element|it must be powered to work. Power connections labeled Vcc+ and Vcc− are shared by both amplifiers. External resistors must be added to complete any op-amp design. Today, we'll build a classic non-inverting amplifier. 3 Figure 4: TL082 op-amp (A) and pinout (B). There are 8 individual electrical contacts{just in time for Halloween! Spider decorations, anyone? Note carefully the half-circle at the \top" of the IC that serves as an orientation mark. Just to the left of this mark is pin 1, as indicated in (B). ICs often show a small dot next to pin 1, as is the case for the particular TL082 package shown in (A). 4.2 Non-inverting Amplifier Speaking of a non-inverting amp, check out Figure 5. To get a first taste of op-amps, we'll wire up this circuit and quickly look at the input and output to understand how it functions. But first, we interrupt this broadcast for an public safety announcement! Figure 5: Non-inverting amplifier configurations. The voltage gain of non-inverting amplifier is Gv = 1 + Rf =Ri: Power connections are ±9 V. First, do NOT power up the op-amp circuits until they are fully wired. Otherwise you run the risk of having something mis-wired, which can lead to a nicely toasted op-amp. The corollary is that you should always power down your circuit before unwiring it and returning components to the bins. Also, you'll quickly notice that the pins extending from the chip are easily bent. When the pins are bent, getting the chip into and out of your board can be a pain. So, take care of your chip, be careful not to bend the pins. Use a small screwdriver to gently wedge underneath the IC then gently rock it free. Easy does it. 4 And we now return to our regular programming... 1. Build the non-inverting amplifier shown in Fig. 5. Use Rf ≈ 5 kΩ, Ri ≈ 500Ω, and R3 ≈ Rf jjRi. For Vin, use a 0.2 V p-p, 100 kHz sine wave. For power supply connections, use±Vcc = ±9 V. Display the input and output voltage sinusoids Vin and Vout simultaneously on the oscilloscope. Carefully sketch what you see. 2. Measure and report the voltage gain. We'll learn in a few weeks that the voltage gain is given by a simple ratio: Gv = 1 + Rf =Ri: How did your measured voltage gain compare to the theoretical value? 3. What is the phase relationship between the input and output? 4.3 AM carrier wave amplifier Now it is time to integrate the non-inverting amp into your AM radio! The job of the amplifier is to boost the signal output from your LC resonator to an amplitude that is compatible with the downstream diode, which requires ≈ 0:6−0:7 V to \turn on." So the voltage gain of the amplifier should be sufficient to achieve an amplifier output signal of ≥ 2 V amplitude (4 V pk-pk). 2 V leaves a little headroom to make sure your diode can go into forward conduction at about 0.6 V. Your task is to choose suitable resistors and build a non-inverting amplifier with an appropriate voltage gain for your AM radio system. For instance, if you previously measured the output signal of your LC resonator is, say, 100 mV, then you need to amplify by a factor of ×20 such that your amplifier outputs ≥ 2V signal. In your design, make sure to use a TL082 variety of op-amp. You should know that there are many amplifier models out there|picking out an op-amp is sort of like picking out a car. The TL082 is a speedy little guy with a high gain-bandwidth product. We need a fast amplifier to handle the radio frequency signals in this case. The gain-bandwidth product specifies the maximum voltage gain that be achieved at a certain frequency. GBW = (maximum voltage gain achievable) × (signal frequency) So let's say we've got a carrier wave at a frequency of 100 kHz and we want to amplify by a factor of ×20. This implies a gain-bandwidth product of GBW = 100kHz × 20 = 2 MHz. The TL082 is spec'd for a 4 MHz gain-bandwidth, so it will be fast enough! 5 5 Buffer Zone: Last stage amplifier Figure 6: Buffer Amplifier. Vout = Vin. The last section of the AM radio is a buffer amplifier built around the \second half" of the TL082 op-amp (remember: there are 2 op-amps in every little 8-leg package). The buffer is shown in Figure 6. We'll see in the coming weeks that for the buffer Vout = Vin. In other words, the buffer’s voltage gain is 1. And you immediately object \What a waste{that's no amplification at all!". Fair enough, my Circuits friends. However, the magic is that this configuration prevents current from being siphoned away from the smoother circuit upstream. This ensures the smoother actually, well, smooths the signal regardless of what it connected further downstream of the buffer. Go ahead and build this little puppy standalone|don't connect it to any of the other AM radio building blocks yet. Verify using your oscilloscope and function generator that, in fact, Vout = Vin. 6 6 Smooth move: Demodulation with Diode rectifier and RC smoother Recall that the job of the diode and RC smoother is to extract the audio signal from the AM waveform. We'll play a few fun circuits tricks (treats?) to do this in a two-step process.
Recommended publications
  • Valve Biasing

    Valve Biasing

    VALVE AMP BIASING Biased information How have valve amps survived over 30 years of change? Derek Rocco explains why they are still a vital ingredient in music making, and talks you through the mysteries of biasing N THE LAST DECADE WE HAVE a signal to the grid it causes a water as an electrical current, you alter the negative grid voltage by seen huge advances in current to flow from the cathode to will never be confused again. When replacing the resistor I technology which have the plate. The grid is also known as your tap is turned off you get no to gain the current draw required. profoundly changed the way we the control grid, as by varying the water flowing through. With your Cathode bias amplifiers have work. Despite the rise in voltage on the grid you can control amp if you have too much negative become very sought after. They solid-state and digital modelling how much current is passed from voltage on the grid you will stop have a sweet organic sound that technology, virtually every high- the cathode to the plate. This is the electrical current from flowing. has a rich harmonic sustain and profile guitarist and even recording known as the grid bias of your amp This is known as they produce a powerful studios still rely on good ol’ – the correct bias level is vital to the ’over-biased’ soundstage. Examples of these fashioned valves. operation and tone of the amplifier. and the amp are most of the original 1950’s By varying the negative grid will produce Fender tweed amps such as the What is a valve? bias the technician can correctly an unbearable Deluxe and, of course, the Hopefully, a brief explanation will set up your amp for maximum distortion at all legendary Vox AC30.
  • Radio Communications in the Digital Age

    Radio Communications in the Digital Age

    Radio Communications In the Digital Age Volume 1 HF TECHNOLOGY Edition 2 First Edition: September 1996 Second Edition: October 2005 © Harris Corporation 2005 All rights reserved Library of Congress Catalog Card Number: 96-94476 Harris Corporation, RF Communications Division Radio Communications in the Digital Age Volume One: HF Technology, Edition 2 Printed in USA © 10/05 R.O. 10K B1006A All Harris RF Communications products and systems included herein are registered trademarks of the Harris Corporation. TABLE OF CONTENTS INTRODUCTION...............................................................................1 CHAPTER 1 PRINCIPLES OF RADIO COMMUNICATIONS .....................................6 CHAPTER 2 THE IONOSPHERE AND HF RADIO PROPAGATION..........................16 CHAPTER 3 ELEMENTS IN AN HF RADIO ..........................................................24 CHAPTER 4 NOISE AND INTERFERENCE............................................................36 CHAPTER 5 HF MODEMS .................................................................................40 CHAPTER 6 AUTOMATIC LINK ESTABLISHMENT (ALE) TECHNOLOGY...............48 CHAPTER 7 DIGITAL VOICE ..............................................................................55 CHAPTER 8 DATA SYSTEMS .............................................................................59 CHAPTER 9 SECURING COMMUNICATIONS.....................................................71 CHAPTER 10 FUTURE DIRECTIONS .....................................................................77 APPENDIX A STANDARDS
  • History of Radio Broadcasting in Montana

    History of Radio Broadcasting in Montana

    University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 1963 History of radio broadcasting in Montana Ron P. Richards The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Let us know how access to this document benefits ou.y Recommended Citation Richards, Ron P., "History of radio broadcasting in Montana" (1963). Graduate Student Theses, Dissertations, & Professional Papers. 5869. https://scholarworks.umt.edu/etd/5869 This Thesis is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. THE HISTORY OF RADIO BROADCASTING IN MONTANA ty RON P. RICHARDS B. A. in Journalism Montana State University, 1959 Presented in partial fulfillment of the requirements for the degree of Master of Arts in Journalism MONTANA STATE UNIVERSITY 1963 Approved by: Chairman, Board of Examiners Dean, Graduate School Date Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number; EP36670 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMT Oiuartation PVUithing UMI EP36670 Published by ProQuest LLC (2013).
  • En 303 345 V1.1.0 (2015-07)

    En 303 345 V1.1.0 (2015-07)

    Draft ETSI EN 303 345 V1.1.0 (2015-07) HARMONISED EUROPEAN STANDARD Radio Broadcast Receivers; Harmonised Standard covering the essential requirements of article 3.2 of the Directive 2014/53/EU 2 Draft ETSI EN 303 345 V1.1.0 (2015-07) Reference DEN/ERM-TG17-15 Keywords broadcast, digital, radio, receiver ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N° 348 623 562 00017 - NAF 742 C Association à but non lucratif enregistrée à la Sous-Préfecture de Grasse (06) N° 7803/88 Important notice The present document can be downloaded from: http://www.etsi.org/standards-search The present document may be made available in electronic versions and/or in print. The content of any electronic and/or print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any existing or perceived difference in contents between such versions and/or in print, the only prevailing document is the print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the current status of this and other ETSI documents is available at http://portal.etsi.org/tb/status/status.asp If you find errors in the present document, please send your comment to one of the following services: https://portal.etsi.org/People/CommiteeSupportStaff.aspx Copyright Notification No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm except as authorized by written permission of ETSI.
  • Maintenance of Remote Communication Facility (Rcf)

    Maintenance of Remote Communication Facility (Rcf)

    ORDER rlll,, J MAINTENANCE OF REMOTE commucf~TIoN FACILITY (RCF) EQUIPMENTS OCTOBER 16, 1989 U.S. DEPARTMENT OF TRANSPORTATION FEDERAL AVIATION AbMINISTRATION Distribution: Selected Airway Facilities Field Initiated By: ASM- 156 and Regional Offices, ZAF-600 10/16/89 6580.5 FOREWORD 1. PURPOSE. direction authorized by the Systems Maintenance Service. This handbook provides guidance and prescribes techni- Referenceslocated in the chapters of this handbook entitled cal standardsand tolerances,and proceduresapplicable to the Standardsand Tolerances,Periodic Maintenance, and Main- maintenance and inspection of remote communication tenance Procedures shall indicate to the user whether this facility (RCF) equipment. It also provides information on handbook and/or the equipment instruction books shall be special methodsand techniquesthat will enablemaintenance consulted for a particular standard,key inspection element or personnel to achieve optimum performancefrom the equip- performance parameter, performance check, maintenance ment. This information augmentsinformation available in in- task, or maintenanceprocedure. struction books and other handbooks, and complements b. Order 6032.1A, Modifications to Ground Facilities, Order 6000.15A, General Maintenance Handbook for Air- Systems,and Equipment in the National Airspace System, way Facilities. contains comprehensivepolicy and direction concerning the development, authorization, implementation, and recording 2. DISTRIBUTION. of modifications to facilities, systems,andequipment in com- This directive is distributed to selectedoffices and services missioned status. It supersedesall instructions published in within Washington headquarters,the FAA Technical Center, earlier editions of maintenance technical handbooksand re- the Mike Monroney Aeronautical Center, regional Airway lated directives . Facilities divisions, and Airway Facilities field offices having the following facilities/equipment: AFSS, ARTCC, ATCT, 6. FORMS LISTING. EARTS, FSS, MAPS, RAPCO, TRACO, IFST, RCAG, RCO, RTR, and SSO.
  • Bias Circuits for RF Devices

    Bias Circuits for RF Devices

    Bias Circuits for RF Devices Iulian Rosu, YO3DAC / VA3IUL, http://www.qsl.net/va3iul A lot of RF schematics mention: “bias circuit not shown”; when actually one of the most critical yet often overlooked aspects in any RF circuit design is the bias network. The bias network determines the amplifier performance over temperature as well as RF drive. The DC bias condition of the RF transistors is usually established independently of the RF design. Power efficiency, stability, noise, thermal runway, and ease to use are the main concerns when selecting a bias configuration. A transistor amplifier must possess a DC biasing circuit for a couple of reasons. • We would require two separate voltage supplies to furnish the desired class of bias for both the emitter-collector and the emitter-base voltages. • This is in fact still done in certain applications, but biasing was invented so that these separate voltages could be obtained from but a single supply. • Transistors are remarkably temperature sensitive, inviting a condition called thermal runaway. Thermal runaway will rapidly destroy a bipolar transistor, as collector current quickly and uncontrollably increases to damaging levels as the temperature rises, unless the amplifier is temperature stabilized to nullify this effect. Amplifier Bias Classes of Operation Special classes of amplifier bias levels are utilized to achieve different objectives, each with its own distinct advantages and disadvantages. The most prevalent classes of bias operation are Class A, AB, B, and C. All of these classes use circuit components to bias the transistor at a different DC operating current, or “ICQ”. When a BJT does not have an A.C.
  • Chapter 4 BJT BIASING CIRCUIT Introduction – Biasing the Analysis Or Design of a Transistor Amplifier Requires Knowledge of Both the Dc and Ac Response of the System

    Chapter 4 BJT BIASING CIRCUIT Introduction – Biasing the Analysis Or Design of a Transistor Amplifier Requires Knowledge of Both the Dc and Ac Response of the System

    Chapter 4 BJT BIASING CIRCUIT Introduction – Biasing The analysis or design of a transistor amplifier requires knowledge of both the dc and ac response of the system. In fact, the amplifier increases the strength of a weak signal by transferring the energy from the applied DC source to the weak input ac signal The analysis or design of any electronic amplifier therefore has two components: •The dc portion and •The ac portion During the design stage, the choice of parameters for the required dc levels will affect the ac response. What is biasing circuit? Biasing: Application of dc voltages to establish a fixed level of current and voltage. Purpose of the DC biasing circuit • To turn the device “ON” • To place it in operation in the region of its characteristic where the device operates most linearly . •Proper biasing circuit which it operate in linear region and circuit have centered Q-point or midpoint biased •Improper biasing cause Improper biasing cause •Distortion in the output signal •Produce limited or clipped at output signal Important basic relationship IECB= II + I β = C I B IE =+≅ (β 1) IIBC VVVCB= CE − BE Operating Point •Active or Linear Region Operation Base – Emitter junction is forward biased Base – Collector junction is reverse biased Good operating point •Saturation Region Operation Base – Emitter junction is forward biased Base – Collector junction is forward biased •Cutoff Region Operation Base – Emitter junction is reverse biased BJT Analysis DC AC analysis analysis Calculate gains of the Calculate the DC Q-point amplifier
  • High Frequency (HF)

    High Frequency (HF)

    Calhoun: The NPS Institutional Archive Theses and Dissertations Thesis Collection 1990-06 High Frequency (HF) radio signal amplitude characteristics, HF receiver site performance criteria, and expanding the dynamic range of HF digital new energy receivers by strong signal elimination Lott, Gus K., Jr. Monterey, California: Naval Postgraduate School http://hdl.handle.net/10945/34806 NPS62-90-006 NAVAL POSTGRADUATE SCHOOL Monterey, ,California DISSERTATION HIGH FREQUENCY (HF) RADIO SIGNAL AMPLITUDE CHARACTERISTICS, HF RECEIVER SITE PERFORMANCE CRITERIA, and EXPANDING THE DYNAMIC RANGE OF HF DIGITAL NEW ENERGY RECEIVERS BY STRONG SIGNAL ELIMINATION by Gus K. lott, Jr. June 1990 Dissertation Supervisor: Stephen Jauregui !)1!tmlmtmOlt tlMm!rJ to tJ.s. eave"ilIE'il Jlcg6iielw olil, 10 piolecl ailicallecl",olog't dU'ie 18S8. Btl,s, refttteste fer litis dOCdiii6i,1 i'lust be ,ele"ed to Sapeihil6iiddiil, 80de «Me, "aial Postg;aduulG Sclleel, MOli'CIG" S,e, 98918 &988 SF 8o'iUiid'ids" PM::; 'zt6lI44,Spawd"d t4aoal \\'&u 'al a a,Sloi,1S eai"i,al'~. 'Nsslal.;gtePl. Be 29S&B &198 .isthe 9aleMBe leclu,sicaf ,.,FO'iciaKe" 6alite., ea,.idiO'. Statio", AlexB •• d.is, VA. !!!eN 8'4!. ,;M.41148 'fl'is dUcO,.Mill W'ilai.,s aliilical data wlrose expo,l is idst,icted by tli6 Arlil! Eurse" SSPItial "at FRIis ee, 1:I.9.e. gec. ii'S1 sl. seq.) 01 tlls Exr;01l ftle!lIi"isllatioli Act 0' 19i'9, as 1tI'I'I0"e!ee!, "Filill ell, W.S.€'I ,0,,,,, 1i!4Q1, III: IIlIiI. 'o'iolatioils of ltrese expo,lla;;s ale subject to 960616 an.iudl pSiiaities.
  • Prof. K Radhakrishna Rao Lecture 2 Role of Analog Signal Processing

    Prof. K Radhakrishna Rao Lecture 2 Role of Analog Signal Processing

    Analog Circuits and Systems Prof. K Radhakrishna Rao Lecture 2 Role of Analog Signal Processing in Electronic Products – Part 1 1 Structure of an electronic product 2 Electronic Products o Process analog signals and digital data o This involve transmission and reception of signals and data o It is generally necessary to code signal and data to transmit over channels o Transmission can be over wires or wireless o Processing and storage are efficient in digital form o Several human interface technologies are available 3 Products considered o Radio Receiver o Modem o Cell Phone o ECG 4 Radio Receiver o AM Receiver o FM Receiver 5 Radio waves are classified as o Low frequency (LF): 30 kHz – 300 kHz, o Medium frequency (MF): 300 kHz – 3 MHz, o High frequency (HF): 3 MHz – 30 MHz, o Very high frequency (VHF): 30 MHz – 300 MHz, o Ultra high frequency (UHF): 300 MHz – 3 GHz, o Super high frequency (SHF): 3 GHz – 30 GHz, o Extremely high frequency (EHF): 30 GHz to 300 GHz. 6 Radio broadcasting o one-way wireless transmission over radio waves to reach a wide audience o takes place in MF (300 kHz – 3 MHz), HF (3 MHz – 30 MHz) and VHF (30 MHz – 300 MHz) regions 7 Major modes of radio broadcasting o Sine wave (single tone) represented by Vtp sin(ωφ+ ) PM (Analog) where φ = phase in radians PSK (Digital) QPSK( Digital) FM (Analog) ω = frequency in rad/sec FSK (Digital) AM, DSB (Analog) V = peak magnitude in volts p ASK (Digital) 8 AM broadcasting o Amplitude of the carrier signal is varied in response to the amplitude of the signal to be transmitted o Amplitude modulation is done by a unit called mixer (nothing but a multiplier) which produces an output output=+( Vpc V pm sinωω m t )sin c t Vpm where ωm is the modulating frequency = m is known as the Vpc ω is the carrier frequency c modulation index.
  • Kidsdictionary.Pdf

    Kidsdictionary.Pdf

    Access Charges: This is a fee charged by local phone companies for use of their networks. Amplitude Modulation (AM) that's the "AM" Band on your Radio: A signaling method that varies the amplitude of the carrier frequencies to send information. The carrier frequency would be like 910 (kHz) AM on your AM dial. Your radio antenna receives this signal and then decodes it and plays the song. Analog Signal: A signaling method that modifies the frequency by amplifying the strength of the signal or varying the frequency of a radio transmission to convey information. Bandwidth The amount of data passing through a connection over a given time. It is usually measured in bps (bits-per- second) or Mbps. Broadband Broadband refers to telecommunication in which a wide band of frequencies is available to transmit information. More services can be provided through broadband in the same way as more lanes on a highway allow more cars to travel on it at the same time. Broadcast To transmit (a radio or television program) for public or general use. In other words, send out or communicate, especially by radio or television. Cable A strong, large-diameter, heavy steel or fiber rope. The word history of cable derives from Middle English, from Old North French, from Late Latin capulum, lasso, from Latin capere, meaning to seize. Calling Party Pays A billing method in which a wireless phone caller pays only for making calls and not for receiving them. The standard American billing system requires wireless phone customers to pay for all calls made and received on a wireless phone.
  • Transistor Biasing

    Transistor Biasing

    Transistor Biasing Transistor Biasing is the process of setting a transistors DC operating voltage or current conditions to the correct level so that any AC input signal can be amplified correctly by the transistor Transistor Biasing- S.Gayathri Priya 1 Need for Biasing A transistors steady state of operation depends a great deal on its base current, collector voltage, and collector current and therefore, if a transistor is to operate as a linear amplifier, it must be properly biased to have a suitable operating point. Establishing the correct operating point requires the proper selection of bias resistors and load resistors to provide the appropriate input current and collector voltage conditions. Transistor Biasing- S.Gayathri Priya 2 Q Point The correct biasing point for a bipolar transistor, either NPN or PNP, generally lies somewhere between the two extremes of operation with respect to it being either “fully-ON” or “fully- OFF” along its load line. This central operating point is called the “Quiescent Operating Point”, or Q-point for short. Transistor Biasing- S.Gayathri Priya 3 BJT Biasing methods The various types of biasing methods are: • Fixed Bias • Collector to base bias • Voltage divider bias Transistor Biasing- S.Gayathri Priya 4 Fixed Bias The transistors base current, IB remains constant for given values of Vcc, and therefore the transistors operating point must also remain fixed.Hence referred as fixed biasing Transistor Biasing- S.Gayathri Priya 5 Fixed Bias This two resistor biasing This type of transistor network is used to establish biasing arrangement is also the initial operating region of beta dependent biasing as the transistor using a fixed the steady-state condition of current bias.
  • The MOS Tetrode Transistor Is Studied in This Project

    The MOS Tetrode Transistor Is Studied in This Project

    AN ABSTRACT OF THE THESIS OF Thawee Limvorapun for the Master of Science (Name) (Degree) in Electrical and Electronics Engineering (Major) 4; -- 7 -- presented on . (Date) Title: THE MOS TETROD.° mr""TcTcm"" Redacted for Privacy Abstract approved: James C. Lodriey The MOS tetrode transistor is studied in this project. This device is ideally suited for high frequency and switching application. In effect it is the solid state analogy of a multigrid vacuum tube performing a very useful multigrid function. A new structure is developed for p-channel 10 ohm-cm. silicon substrate of (111) crystal orientation. This structure consists of an aluminum con- trol gate G1 buried in the pyrolytic SiO2, or E-gun evapo- ration SiO with thermal oxide for the control gate in- 2' sulator. An offset gate G2 produces another channel L2 and causes a longer pinchoff region in the device. The drain breakdown can be maximized so as to approach bulk breakdown as the result of the redistribution of the surfacefield. is very low, ap- The Miller feedback capacitance CGl-D proaching values similar to those of the vacuum pentodes. This paper describes the design, artwork, pyrolytic SiO and E-gun evaporation SiO process. The V-I 2 2 characteristics, dynamic drain resistance, capacitance, small signal equivalent circuit and large signal limitation, and drain breakdown voltage are also discussed. THE MOS TETRODE TRANSISTOR by Thawee Limvorapun A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Master of Science June 1973 APPROVED: Redacted for Privacy Associa e rofessor of Electrical andEleC-E-Anics Engineering in charge of major Redacted for Privacy Head of Department of Electrical and Electronics Engineering Redacted for Privacy Dean of Graduate School Date thesis is presented 6- 7- 7 2 Typed by Erma McClanathan for Thawee Limvorapun ACKNOWLEDGMENTS I wish to express my sincere appreciation to my advisor, Professor James C.