Experiment 3 - High Amplifiers.

S. Levy, H. Moalem, D. Ackerman and Dr. H. Matzner. Febuary, 2009.

Contents

1Objectives 2

2 Prelab Exercise 2

3 Background Theory 2 3.1 The amplifier which we will use - Mini-Circuits amplifier ERA 3+ 3 − 3.2 General Definitions...... 3 3.3OperatingFrequencyRange...... 3

3.4 S21-Gain...... 4 3.5 S11 and S22 Input and Output SWR ...... 4 − 3.6 S12 ReverseIsolation...... 4 3.7GainFlatness...... − 4 3.8OutputPowerat1dBCompression...... 5 3.9 Dynamic Range of an Amplifier...... 6 3.10IntermodulationProducts...... 6 3.11NoiseFigure(NF)...... 8 3.11.1TheImportanceofNF...... 8 3.11.2NoiseFigureMeasurement-GainMethod...... 9

4 Experiment Procedure 10

4.1RequiredEquipment...... 10 4.2SParameters-SimulationandMeasurement...... 10 4.2.1 Simulation...... 10 4.2.2 Measurement...... 11 4.31dBCompressionPoint-SimulationandMeasurement...... 15 4.3.1 Simulation...... 15 4.3.2 Measurement...... 16 4.4 Third Order Intermodulation Products Point - Simulation and Measurement...... 17 4.4.1 Simulation...... 17

1 4.4.2 Measurement...... 18 4.5AbsoluteNoisePowerMeasurement...... 19 4.5.1 Measurement...... 19 4.6 Noise Figure of Cascade Amplifiers...... 20 4.6.1 Measurement...... 20 4.7DynamicRangeandMinimumDetectableSignal...... 21 4.8FinalReport...... 22

5 Appendix A - Data Sheet of the ERA-3+ Amplifier 22

1Objectives

Upon completion of this study, the student will become familiar with the fol- lowing topics: 1. Basic operation of the amplifier. 2. 1 dB compression point. 3. Third order intermodulation products. 4. Noise figure of an amplifier.

2 Prelab Exercise

1. Define the terms: ’dynamic range’, ’minimum detectable signal’, ’1 dB com- pression point’ and ’third order intercept point’. 2.Explainhowyouintendtomeasurethenoisefigure of a preamplifier using a , 50 Ω termination and another preamplifier. 3. Calculate the Minimum Detectable Signal (MDS) for B = 100 kHz, NF = 2.65 dB, G =22dB and SNR =5dB, according to the equation:

MDS [dBm]= 174 + 10 log B + NF [dB]+G [dB]+SNR[dB] − 3 Background Theory

The components which we have discussed so far in previous experiments have been primarily linear and passive, but any useful RF or microwave system, such as a receiver, will require some nonlinear and active components. Such devices include amplifiers, diodes and mixers, which can be used for detection, mixing, amplification and frequency conversion. An RF power amplifier is a type of electronic amplifier used to convert a low-power radio-frequency signal into a larger signal of significant power.

2 3.1 The amplifier which we will use - Mini-Circuits am-

plifier ERA 3+ − An industrial preamplifier which we will discuss later is shown in Figure 1.

C1 Input capacitor

Amplifier R1 ERA-3

R2 C2 Output capacitor

C3 Figure 1 - A preamplifier.

3.2 General Definitions Amplifier are classified by several attributes, namely: * Operating Frequency Range. *Gain. *GainFlatness. * Output Power at 1 dB Compression. * Input and Output SWR. *DynamicRange. * Noise Figure. * Intercept point.

3.3 Operating Frequency Range

The operating frequency range is the range of over which the ampli- fier will meet the specification parameters. The amplifier may perform beyond this frequency range (without any commitment).

3 Ω er. (1) fi er is fi er, the SWR er. fi fi 22 S er’s gain over the operating ned temperature within the fi | fi 21 S | . In general, SWR of a single stage gure. The SWR of an ampli Ω xed de fi fi 50 4 oss the operating frequency range. 12 )=10log er is measured by viewing the gain variation S ers are designed as close as possible to 50 fi fi dB 21 ( S G er’s actual impedance, Z, with respect to the desired Input and Output SWR erence between the minimum gain and the maximum fi ned as the ratio of the power measured at the output of ff fi − nes the isolation between input and output of an ampli fi 22 11 ),whichisinmostcases S atness of an ampli 0 fl Reverse Isolation Z and S − -Gain Figure 1: Figure 2 - Scattering parameters of an ampli er to the power provided to the input port. It is usually expressed in fi 12 21 11 atness describes the variation in an ampli er can be no greater than 2:1. When cascading such ampli fl fi The gain impedance ( the measure of an ampli impedance. However, thisto is simultaneously not achieve always a possible, good especially noise when attempting Gain 3.6 S Reverse isolation de Typically reverse isolation is twice the gain. 3.7 Gain Flatness 3.4 S Small signal gain isan de ampli and is typically measured acr 3.5 S Most RF and microwave ampli frequency range (see Figure 3) at any operating temperature range. and determining the di ampli could be about 2.5:1. gain recorded over the operation frequency range.

Gain (max) Gain variation (dB) Gain (min) Gain(dB)

Frequency Range Figure 3 - Gain flatness.

3.8 Output Power at 1 dB Compression The 1dB output compression point of an amplifier is defined as the output power level at which the gain degrades from the small signal gain by 1 dB. All active components have a linear dynamic range. This is the range over which the output power varies linearly with respect to the input power. As the output power increases to near its maximum, the device will begin to saturate. The point at which the saturation effects are 1 dB from linear is defined as the 1 dB compression point (see Figure 4). Because of the nonlinear relation between the input and output power at 1 dB compression, the following equation holds:

Pout = Pin + GLinear 1dB (2) 1dB 1dB −

1 dB Linear compression Region RFpower output RFInput power

Figure 4 - 1dB compression point.

5 3.9 Dynamic Range of an Amplifier Suppose that we have an amplifier which fulfill:

Pout =10Pin for a specified range of input power. When the input power increases, the amplifier is no longer a linear component and the output begins to saturate. When the input power decreases to zero, there is still an output power from in- ternal and external noise. This level of power caused by the amplifier’s internal noise is often called noise floor level of the component. Typical values can range from -60 dBm to -100 dBm over the bandwidth of the system, with lower values being obtainable with cooled components. A quantitative measure of the onset of saturation is called the ’1 dB compression point’, which is defined as the input power for which the output is 1 dB below the power of an ideal amplifier. If the input power is excessive, the amplifier can be destroyed. A typical graph of the behavior of this amplifier is shown in Figure 5.

Ideal amolifier

burn 1dBcompression out point point

small signal gain dynamic range

SNR output power(dBm) Noise level

Input power (dBm)

Figure 5 - Dynamic range.

3.10 Intermodulation Products The non-linear behavior of a component causes undesired output harmonics. In general, the voltage of a non-linear device is:

2 3 vout = a0 + a1vin + a2vin + a3vin + ... (3) For amplifier, the desired response is the linear. Higher order responses are undesired.

6 If the input of a component consists of a single frequency (or tone), for example vin =cosf1t, then the output voltage will consist of all harmonics mf1. where m is called the order of the harmonics. For an amplifier we need only order = 1, and the presence of higher harmonics is called harmonic . If an amplifier had a bandwidth of an octave or more, the second-order distortion product of a low-frequency signal could be in the passband of the amplifier. If the input to the system consist of two relatively closely, spaced frequencies (two-tones), say vin =cosf1t +cosf2t, the output spectrum will consist of all harmonics of the form mf1 + nf2,where m and n are positive or negative integers. The order of a given product is then defined as m + n . The v2 term | | | | in will produce harmonics at the frequencies 2f1,2f2,f1 f2 and f1 + f2,which are all second order products. These frequencies can be fi−ltered out, except the case of a broadband amplifier. 3 The vin term will lead to third-order products, such as 3f1, 3f2, 2f1+f2,which can be filtered, but 2f1 f2 and 2f2 f1 cannot be filtered even for a narrow- band system. These products,− which− result from mixing two input signals, are called the ’intermodulation distortion’. Hence these two products will set the 3 dynamic range or bandwidth of the amplifier. Higher powers than vin can also contribute to the intermodulation distortion, but generally these contributions are not dominant. These spurious signals are characterized with respect to the input signal by means of a theoretical tool called ’the intercept point’. This point is defined as the point where the linear curve of the input Vs. output power of the fun- damental signal would intersect with the linear curve of the spurious signal if saturation effects would not limit the output levels of these signals (see Figure 6). Since it is known that the second order spurious products (f2 f1) have a slope of 2:1 with respect to the fundamental input power, the value± of the spurs can be estimated if the input power (Pin) and the output second order intercept point are known. The relationship is as follows: A measure of the second or third-order intermodulation distortion is given by the intercept points. An example of a graph with interception points is given in Figure 6, for the frequencies f1 or f2. The amplifier will work well for a input power which is below the third interception point.

7 Third order 1 dB intercept compression point

small signal second order gain spurious product free dynamic range output power(dBm) output Noise level Input power(dBm) Figure6-IP3point.

3.11 NoiseFigure(NF) Noise figure represents the degradation in signal to noise ratio as the signal passes through a device or a system. F is the noise factor of the system and is calculated as: S /N F = in in (4) Sout/Nout

Where Sin/Nin and Sout/Nout are the input and output signal-to-noise ra- tios. Since all devices add a finite amount of noise to the signal, F is always greater than 1. Alternatively, noise figure may be defined in terms of dB units:

NF =10log F = Sin/Nin [dB] Sout/Nout [dB] (5) 10 − 3.11.1 The Importance of NF The increased in low noise preamplifier and other RF components usage leads to a need for reliable and inexpensive noise figure measurement systems. If no specialized equipment is available, the problem of measuring NF can be solved using modern spectrum analyzer as a noise power meter.

Why noise figure is important Noise figure is a key performance parameter in many RF systems. A low noise figure provides improved signal to noise ratio for analog receivers, and reduces bit error rate in digital receivers. As a parameter in a communications link budget, a lower receiver noise figure allows smaller antennas or lower transmitter power for the same system performance.

8 3.11.2 Noise Figure Measurement - Gain Method This method is based on direct noise measurement and is applied using the measurement setting, as shown in Figure 7, and pre-determining the gain of the DUT. Assuming Sin = Nin we get:

Sin/Nin Nout kTBG1G2 + Nadded Pmeasured Ftotal = = = = (6) Sout/Nout Sout kTBG1G2 kTBG1G2

Where FTotal - total noise factor of the DUT and the preamplifier. Pmeasured - noise power in Watts, displayed on the spectrum analyzer. B - noise bandwidth. G1 and G2 - linear gains of the DUT and preamplifier respectively. 23 1 k - Boltzmann constant (1.38 10− Joul Kelvin− ). · · T - temperature in Kelvin (room temp = 27 ◦C = 300 K). The noise factor of two cascading ampli£ fiers is: ¤

F2 1 Ftotal = F1 + − (7) G1

Where F1 and F2 - noise factors of the DUT and preamplifier respectively. If the NF of the preamplifier and gain of the DUT are known, one can calculate the noise factor of the DUT by:

F2 1 F1 = Ftotal − (8) − G1

preamplifier Spectrum analyzer DUT

50 Ohm G1 G2 termination

NF=? NF=known

Figure 7 - Equipment setting for gain method.

This measurement set-up is valid, when implementing the following rules:

The DUT is matched with the characteristic impedance, Z0. • In order to minimize the effect of the second amplifier,wehavetochoose • low noise amplifier, (minimum noise figure) while the gain of the DUT is sufficient large (see equation 7). The spectrum analyzer has the capability of measuring noise (the ability • to correct the bandwidth of the measurement and take into account the random nature of the noise).

9 Maximum accuracy could be achieved when Pmeasured DANL +10 dB • (DANL - ’Displayed Average Noise Level’ of the spectrum≥ analyzer).

The advantages of this method are:

Low price and measurement simplicity - only absolute power value read- • ing on spectrum analyzer, and minimum measuring set. It is possible to perform quick noise figure measurement in a wide frequency range, thanks to the sweeping capability of the spectrum analyzer. Output instability or other interference can be easily seen. • The major disadvantage of this method are:

The spectrum analyzer has the capability of measuring accurately only • very low noise signal (DANL < 120dBm). − The gain of the DUT should be at least 10 dB for reasonable accuracy. • This method requires that the gain of the DUT is known already. Also, • the accuracy of Noise Figure measured depends directly on the accuracy of the measured Gain.

4 Experiment Procedure

4.1 Required Equipment 1. Network analyzer. 2. RF power amplifier Mini-Circuit ERA 3+. 3. DC power supply. − 4. Two signal generators. 5. Attenuator.

4.2 S Parameters - Simulation and Measurement. 4.2.1 Simulation 1. Simulate the preamplifier Mini-circuit ERA 3+, accordingtoFigure1. −

10 S-PARAMETERS

S_Param SP1 Start=10 MHz Stop=1 GHz Step=1.0 MHz

Term Term Term2 Term1 va_mc_ZFL-1000LN_19930601 Num=2 Num=1 Amp1 Z=50 Ohm Z=50 Ohm

Figure 1 - S-parameter simulation.

2. Simulate all the S parameters (S11,S22,S21 and S12) of the preamplifier as a function of frequency. Frequency range 50MHz 1GHz. Save the data on magnetic media. −

4.2.2 Measurement For the old network analyzers 3. Set the power level of the network analyzer to -10 dBm by pressing POWER, Level, -10 dBm and set the frequency range to 50 MHz 1 GHz 4. Connect a coaxial cable− between port 1 and port 2 of the network analyzer, as shown in Figure 2 (If the network analyzer can’t reach to a power level of 10 dBm, than add an appropriate attenuator, as shown in Figure 5). Preform a− transmission calibration.

11

RF RF out IN

Coaxial cable Figure 2 - Transmission calibration, without attenuator. 5. Disconnect the coaxial cable from port 1 and connect the amplifier between port 1 and the coaxial cable, as shown in Figure 3. Connect the amplifier to a DC power supply of 12V. Measure S21 and S12. Save the data on magnetic media. Important: Pay attention to the polarity and to the input power level, otherwise you may blow up the amplifier!

Network Analyzer HP- 8714

RF RF OUT IN

ERA-3+

Figure 3 - Transmission measurement, without attenuator. 6. Disconnect the amplifier and the coaxial cable from the network analyzer and preform a reflection calibration. 7. Connect the IN port of the amplifier to port 1 of the network analyzer and the OUT port of the amplifier to a 50 Ω termination, as shown in Figure 4.

12 Measure S11 and S22. Save the data on magnetic media.

Network Analyzer HP- 8714

RF RF OUT IN

ERA-3+ Load 50Ω

Figure 4 - Reflection measurement, without attenuator.

Compare the measured result to the simulated result. Compare the measured SWR input, SWR output and gain to the data sheet (see appendix A).

For the new network analyzer 3. Set the power level of the network analyzer to -5 dBm by pressing Sweep Setup, Power, -5 dBm and set the frequency range to 50 MHz 1 GHz. 4. Connect a 6 dB attenuator− to port 1 of the network analyzer and a coaxial cable between the attenuator and port 2 of the network analyzer, as shown in Figure 5. Preform a transmission calibration.

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Network Analyzer HP-8714

RF OUT RF IN ttenuator At BPF 10.7 MHz 10.7

Figure 5 - Transmission calibration, with attenuator. 5. Disconnect the coaxial cable from the attenuator and connect the amplifier between the attenuator and the coaxial cable, as shown in Figure 6. Connect the amplifier to a DC power supply of 12V. Measure S21 and S12. Save the data on magnetic media. Important: Pay attention to the polarity and to the input power level, otherwise you may blow up the amplifier!

Network Analyzer HP- 8714

RF RF OUT IN

Attenuator ERA-3+

Figure 6 - Transmission measurement, with attenuator.

14 6. Disconnect the amplifier and the coaxial cable from the network analyzer and preform reflection calibration. 7. Connect the IN port of the amplifier to the attenuator and the attenu- ator connect to port 1 of the network analyzer. Connect the OUT port of the amplifier to a 50 Ω termination, as shown in Figure 7. Measure S11 and S22. Save the data on magnetic media.

Network Analyzer HP- 8714

RF RF OUT IN Attenuator

ERA-3+ Load 50Ω

Figure 7 - Reflection measurement, without attenuator. Compare the measured result to the simulated result. Compare the measured SWR input, SWR output and gain to the data sheet (see appendix A).

4.3 1 dB Compression Point - Simulation and Measure- ment. 4.3.1 Simulation 1. Simulate the preamplifier Mini-circuit ERA 3+, accordingtoFigure8. −

15 GAIN COMPRESSION HARMONIC BALANCE SWEEP PLAN XDB Sw eepPlan HarmonicBalance HB2 HB1 Sw pPlan1 Freq[1]=RFfreq Freq[1]=1.0 GHz Start=-30 Stop=10.0 Step=1.0 Lin= Order[1]=5 UseSw eepPlan= Order[1]=5 GC_XdB=1 Sw eepPlan= Sw eepVar="Pin" GC_InputPort=1 Reverse=no Sw eepPlan="Sw pPlan1" GC_OutputPort=2 Pout GC_InputFreq=1.0 GHz Term GC_OutputFreq=1.0 GHz P_1Tone Term2 GC_InputPow erTol=1e-3 PORT1 va_mc_ZFL-1000LN_19930601 Num=2 GC_OutputPow erTol=1e-3 Num=1 Amp1 Z=50 Ohm GC_MaxInputPow er=100 Var Z=50 Ohm Eqn VAR P=dbmtow (Pin) VAR1 Freq=RFfreq Hz RFfreq=1GHz Pin=- 5

Figure 8 - 1dB compression point simulation.

2. Draw the graph of the idealized linear power gain and the graph of the actual power curve. Do so by constructing the equations: Linear=Gain[1]+XDB1,HB1,HB1,HB,Pin Gain=dBm(XDB1,HB1,HB1,HB,Vout[1])-XDB1.HB1.HB.Pin Where ’Linear’ is the idealized linear power gain and ’Gain’ is the graph of the actual power curve. 3. Find the exact 1 dB point at the data display window by placing two markers, one marker on the linear curve and the other on the actual curve and turn on delta marker mode. What is the input power which result in a difference of 1dB between the markers? Save the data.

4.3.2 Measurement For the old network analyzers 4. Set up the network analyzer by pressing BEGIN, Amplifier and Transmission. Choose power sweep instead of fre- quency sweep by pressing SWEEP, Power Sweep. Choose Continuous Wave for only one frequency of 1GHz by pressing FREQ, CW, 1GHz.Setthepower sweep range to its maximum by pressing POWER, PwrSweepRange, -6 to Max(dBm),PriorMenu,Start,-6dBm,Stop,20dBm. 5. Connect a 20dB attenuator to the network analyzer with a coaxial ca- ble, as shown in Figure 5. Preform a transmission calibration and connect the amplifier between the attenuator and the coaxial cable, as shown in Figure 6. Connect the amplifier to a DC power supply of 12V.

For the new network analyzer 4. Set up the network analyzer by pressing

16 Meas, S21. Choose power sweep instead of frequency sweep by pressing Sweep Setup, Sweep Type, Power Sweep. Choose Continuous Wave for only one frequency of 1GHz by pressing Power, CW Freq, 1GHz. Set the power sweep range by pressing Start, -5 dBm, Stop, 10 dBm. 5. Connect a 10 dB attenuator to the network analyzer with a coaxial cable, as shown in Figure 5. Preform a transmission calibration and then connect the amplifier between the attenuator to the coax cable, as shown in Figure 6. Connect the amplifier to a DC power supply of 12 V . Important : Pay attention to the polarity and the input power level, other- wise you could blow up the amplifier! 6. A graph of the Pout/Pin versus Pin is displayed. Place a marker on the graph and find the Pin which result in a 1 dB drop in the Pout/Pin value. Save the data on magnetic media. According to the data sheet, the 1dB compression point at 1GHz is 12.53dBm. Compare your result to the theoretical.

4.4 Third Order Intermodulation Products Point - Simu- lation and Measurement. In this part of the experiment you will simulate and measure the IP3 of a preamplifier.

4.4.1 Simulation 1. Simulate the preamplifier according to Figure 9.

HARMONIC BALANCE

HarmonicBalance HB1 Freq[1]=1 GHz Freq[2]=999 MHz Order[1]=3 Order[2]=3

Attenuator BPF_Elliptic Attenuator P_1Tone ATTEN1 BPF1 ATTEN2 PORT2 Loss=3 dB Fcenter=1 GHz Loss=6 dB Num=2 VSWR=1 BWpass=100 MHzVSWR=1 Pout Z=50 Ohm Ripple=0.01 dB P=dbmtow(-15) PwrSplit2 Attenuator Attenuator BWstop=200 MHz va_mc_ZFL-1000LN_19930601 Term Freq=1 GHz PWR1 ATTEN5 ATTEN6 Astop=40 dB Amp1 Term3 S21=0.707 Loss=3 dB Loss=3 dB Num=3 S31=0.707 VSWR=1 VSWR=1 Z=50 Ohm

Attenuator BPF_Elliptic Attenuator P_1Tone ATTEN3 BPF2 ATTEN4 PORT1 Loss=3 dB Fcenter=999 MHz Loss=6 dB Num=1 VSWR=1 BWpass=100 MHzVSWR=1 Z=50 Ohm Ripple=0.01 dB P=dbmtow(-15) BWstop=200 MHz Freq=999 MHz Astop=40 dB

Figure 9 - IP3 simulation.

17 2. Drew a graph of Pout [dBm] as a function of frequency. Double click on the graph, go to ’Trace Options’ and change the selected type from ’Auto’ to ’Spectral’. Double click on the graph, go to ’Plot Options’ and set the frequency range to 990MHz-1010MHz. Save the data on magnetic media. A typical view of intermodulation products is shown in Figure 10.

IM,dBc=A Amplitude

2F!-F2F2 F1 2F2-F1 Frequency Figure 10 - Intermodulation products.

3. Calculated the IP3,using the formula IP3=P + A/2, where P is the output power of the fundamental signal (f1or f2). 4. Change the power of the input generators to -20dBm and drew the same graph as in paragraph 2. Save the data on magnetic media. Verify that the IP3 point has no major changes.

4.4.2 Measurement 5. Connect the system as indicated in Figure 11.

Sig. 3dB- 6dB BPF Gen.1 pad pad

Comb 3dB- DUT 3dB- Spectrum pad pad Analyzer iner

Sig. 3dB- 6dB BPF Gen.1 pad pad

Figure 11 - System configuration for an IP3 measurement..

18 6.SetSigGen.1tofrequency1000MHz and amplitude 15dBm. Set Sig Gen2. to frequency 999MHz and amplitude 15−dBm. Watch the fundamental and third order products on− the spectrum analyzer (set the spectrum to an average of 20). Save the data on magnetic media. 7. Fill in Table-1: Signal [dBm] 1storder freq.&Amp. 3rd order freq. &Amp. IP3 [dBm] -15 -20 Table-1 8. Compare your simulated result to your measured result of the IP3 and to the theoretical one.

4.5 Absolute Noise Power Measurement In this part of the experiment you will measure the noise floor of a spectrum analyzer.

4.5.1 Measurement 1. Connect a 50 Ω termination to the input of the spectrum analyzer, as shown in Figure 12.

Spectrum Analyzer Agilent-ESA Load 50Ω

Figure 12 - Measuring the noise floor of a spectrum analyzer.

2. Set the spectrum analyzer to center frequency of 100 MHz,spanof 1 kHz, average on and a reference level of 100 dBm. 3. Measure the noise floor of the spectrum− analyzer by using marker noise:

For the new spectrum analyzers Press Marker, More, Function, Marker Noise.

19 For the old spectrum analyzers Press MKR FCTN, MK NOISE, ON. Save the data on magnetic media.

4.6 Noise Figure of Cascade Amplifiers In this part of the experiment you will calculate the noise figure of one amplifier by measuring the noise figure of cascade amplifiers.

4.6.1 Measurement 1. Set the power level of the network analyzer to 10 dBm and the frequency range to 50 MHz 1 GHz. Connect a coaxial cable− between port 1 and port 2 of the network analyzer,− as shown in Figure 2 (If the network analyzer can’t reach to a power level of 10 dBm, than add an appropriate attenuator, as shown in Figure 5). Preform− a transmission calibration. 2. Connect two series amplifiers to the network analyzer (don’t forget the attenuator, if needed), as shown in Figure 13. Important: Pay attention to the polarity and to the input power level, otherwise you may blow up the amplifier!

Network Analyzer HP- 8714

RF RF OUT IN

ERA-3+ ERA-3+

Figure 13 - Measuring the gain of a cascade of two amplifiers.

3. Measure the linear gain (S11) of two cascade amplifiers (G1G2)at100 MHz. Save the data on magnetic media. 4. Connect two amplifiers in series, as shown in Figure 14.

20 Spectrum Analyzer Agilent-ESA

ERA-3+

ERA-3+ Load 50Ω

Figure 14 - Measuring noise figure of cascade amplifiers.

5. 2. Set the spectrum analyzer to center frequency of 100 MHz,spanof 100 kHz. Measure the noise power (in Watts) by the noise marker. 6. Calculate the noise figure of the first amplifier. 7. Compare your measured result of the NF to the theoretical one.

4.7 Dynamic Range and Minimum Detectable Signal 1. Connect the system as indicated in Figure 14.

21

Signal Generator Agilent 8648 Spectrum Analyzer ESA-E

515.000,00 MHz

ERA-3+

ZFL-1000LN

Figure 14 - Dynamic range and minimum detectable signal measurement.

2. Set the spectrum analyzer to center frequency 500 MHz,span100 kHz, attenuation 0 dB and average on. Set the signal generator to 500 MHz and an amplitude which is comparable to SNR of 5 dB. Verify that the calculated MDS (question 3 from the ’Prelab Exercise’) is within 3 dB of the measured MDS. 3. Calculate the dynamic range (DR) as:

DR [dB]=Pout_1dB [dB] MDS[dB] − 4.8 Final Report 1. Attach and explain all the graphs and simulation results. 2. Draw a graph of the output third order intercept point for the preamplifier mini-circuit ERA 3+ (see Figure 6 of the ’Background Theory’ part). − 5 Appendix A - Data Sheet of the ERA-3+ Am- plifier

Gain at 50 MHz - 22.97 dB. Gain at 1 GHz - 21.13 dB. 1 dB compression point at 50 MHz - 12.72 dBm. 1 dB compression point at 1 GHz - 12.53 dBm. IP3 at 50 MHz - 26.87 dBm. IP3 at 1 GHz - 27.45 dBm. NF at 100 MHz - 2.7 dBm. NF at 1 GHz - 2.6 dBm.

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