Network Analyzer Basics Author David Ballo Network Analyzer

Network Analyzer Basics Author: David Ballo Network Analyzer Basics DJB 12/96 na_basic. pre 1

Network analysis is not. . . Router Bridge Repeater Hub Your IEEE 802. 3 X. 25 ISDN switched-packet data stream is running at 147 MBPS with a -9 BER of 1. 523 X 10. . . Network Analyzer Basics DJB 12/96 na_basic. pre 2

Duplexers Diplexers Filters Couplers Bridges Splitters, dividers Combiners Isolators Circulators Attenuators Adapters Opens, shorts, loads Delay lines Cables Transmission lines Waveguide Resonators Dielectrics R, L, C's Low Integration High What types of devices are tested? Passive RFICs MMICs T/R modules Transceivers Receivers Tuners Converters Antennas Switches Multiplexers Mixers Samplers Multipliers Diodes Device type VCAs Amplifiers VCOs VTFs Oscillators Modulators VCAtten's Transistor s Active Network Analyzer Basics DJB 12/96 na_basic. pre 3

Device Test Measurement Model Complex 84000 RFIC test Ded. Testers VSA SA Harm. Dist. LO stability Image Rej. Gain/Flat. Compr'n Phase/GD AM-PM Isolation Rtn Ls/VSWR Impedance S-parameters Response tool VNA TG/SA SNA NF Mtr. NF Imped. An. Simple Param. An. Power Mtr. Det/Scope Intermodulation Distortion NF Full call sequence Pulsed S-parm. Pulse profiling BER EVM ACP Regrowth Constell. Eye LCR/Z I-V Measurement plane Absol. Power Gain/Flatness DC CW Simple Swept freq RF Swept power Noise 2 -tone Stimulus type Multitone Complex Pulsedmodulation Protocol Complex Network Analyzer Basics DJB 12/96 na_basic. pre 4

Agenda l l Why do we test components? What measurements do we make? è è l Network analyzer hardware è è è l Signal separation devices Broadband versus narrowband detection Dynamic range T/R versus S-parameter test sets Three versus four samplers Error models and calibration è l Smith chart review Transmission line basics Reflection and transmission parameters S-parameter definition Types of measurement error One- and two-port models Error-correction choices TRL versus TRL* Basic uncertainty calculations Typical measurements Advanced topics Network Analyzer Basics DJB 12/96 na_basic. pre 5

Why do we need to test components? Components often used as building blocks Need to verify specifications l Examples: èfilters to remove harmonics èamplifiers to boost LO power èmixers to convert reference signals l When used to pass communications signals, need to ensure distortionless transmission Linear networks èconstant amplitude èlinear phase / constant group delay l Nonlinear networks èharmonics, intermodulation ècompression ènoise figure l When absorbing power (e. g. an antenna), need to ensure good match Network Analyzer Basics DJB 12/96 na_basic. pre 6

Linear Versus Nonlinear Behavior A * Sin 360° * f ( t - t ) ° A Linear behavior: input and output frequencies are the same (no additional frequencies created) loutput frequency only undergoes magnitude and phase change l Time to Sin 360° * f * t A Time f 1 Input phase shift = to * 360° * f Frequency Output DUT Nonlinear behavior: f output frequency may undergo frequency shift (e. g. with mixers) ladditional frequencies created (harmonics, intermodulation) l 1 Frequency Time f 1 Frequency Network Analyzer Basics DJB 12/96 na_basic. pre 7

Criteria for Distortionless Transmission Linear Networks Linear phase over bandwidth of interest Phase Magnitude Constant amplitude over bandwidth of interest Frequency Network Analyzer Basics DJB 12/96 na_basic. pre 8

Magnitude Variation with Frequency F(t) = sin wt + 1 /3 sin 3 wt + 1 /5 sin 5 wt Time Magnitude Linear Network Frequency H Network Analyzer Basics DJB 12/96 na_basic. pre Frequency Network Analyzer Basics DJB 12/96 na_basic. pre 9

Phase Variation with Frequency F(t) = sin wt + 1 /3 sin 3 wt + 1 /5 sin 5 wt Linear Network Time Magnitude Time 0° Frequency -180° Frequency -360° Network Analyzer Basics DJB 12/96 na_basic. pre 10

Criteria for Distortionless Transmission Nonlinear Networks Saturation, crossover, intermodulation, and other nonlinear effects can cause signal distortion Time Frequency Network Analyzer Basics DJB 12/96 na_basic. pre 11

Example Where Match is Important KPWR FM 97 Wire and bad antenna (poor match at 97 MHz) results in 150 W radiated power KPWR FM 97 Proper transmission line and antenna results in 1500 W radiated power - signal is received about three times further! Good match between antenna and RF amplifier is extremely important to radio stations to get maximum radiated power Network Analyzer Basics DJB 12/96 na_basic. pre 12

The Need for Both Magnitude and Phase S 1. Complete characterization of linear networks 21 S 11 S S 22 4. 12 Time Domain Characterization Mag 2. Complex impedance needed to design matching circuits Time High Frequency Transistor Model 5. Vector Accuracy Enhancement Base 3. Complex values needed for device modeling Error Collector Measured Emitter Actual Network Analyzer Basics DJB 12/96 na_basic. pre 13

Agenda l l l Why do we test components? What measurements do we make? Network analyzer hardware Error models and calibration Typical measurements Advanced topics Network Analyzer Basics DJB 12/96 na_basic. pre 14

High-Frequency Device Characterization Lightwave Analogy Incident Transmitted Reflected Network Analyzer Basics DJB 12/96 na_basic. pre 15

Smith Chart Review . +j. X 90 o Polar plane 1. 0. 8. 6 0 ¥ +R . 4 + 180 - 0 -j. X o . 2 0 o ¥ Rectilinear impedance plane -90 o Constant X Z L = Zo G= Smith Chart maps rectilinear impedance plane onto polar plane Constant R 0 Z L = 0 (short) G= 1 ± 180 Z L= O G =1 (open) 0 O Smith Chart Network Analyzer Basics DJB 12/96 na_basic. pre 16

Power Transfer RS RL For complex impedances, maximum power transfer occurs when ZL = ZS* (conjugate match) Zs = R + j. X RL / R S ZL = Zs* = R - j. X Maximum power is transferred when RL = RS Network Analyzer Basics DJB 12/96 na_basic. pre 17

Transmission Line Review Low frequencies I Wavelength >> wire length l Current (I) travels down wires easily for efficient power transmission l Voltage and current not dependent on position l High frequencies Wavelength » or << wire (transmission line) length l Need transmission-line structures for efficient power transmission l Matching to characteristic impedance (Z 0) important for low reflection l Voltage dependent on position along line l is very Network Analyzer Basics DJB 12/96 na_basic. pre 18

Transmission Line Terminated with Zo Zs = Zo Zo = characteristic impedance of transmission line Zo V inc Vrefl = 0! (all the incident power is absorbed in the load) For reflection, a transmission line terminated in Zo behaves like an infinitely long transmission line Network Analyzer Basics DJB 12/96 na_basic. pre 19

Transmission Line Terminated with Short, Open Zs = Zo V inc Vrefl In phase (0 ) for oopen o Out of phase (180 ) for short For reflection, a transmission line terminated in a short or open reflects all power back to source Network Analyzer Basics DJB 12/96 na_basic. pre 20

Transmission Line Terminated with 25 W Zs = Zo ZL = 25 W V inc Vrefl Standing wave pattern does not go to zero as with short or open Network Analyzer Basics DJB 12/96 na_basic. pre 21

High-Frequency Device Characterization Incident Transmitted R B Reflected A TRANSMISSION REFLECTION Reflected Incident = SWR S-Parameters S 11, S 22 Reflection Coefficient G, r A Transmitted R Incident Return Loss Impedance, Admittance R+j. X, G+j. B = B R Group Delay Gain / Loss S-Parameters Transmission S 21, S 12 Coefficient T, t Insertion Phase Network Analyzer Basics DJB 12/96 na_basic. pre 22

Reflection Parameters Reflection Coefficient G Vreflected = = Vincident Return loss = -20 log(r), r r F = 0 ZL + ZO G Emax Emin No reflection (ZL = Zo) = ZL - ZO r Voltage Standing Wave Ratio Emax VSWR = Emin = 1+r 1 -r Full reflection (ZL = open, short) 1 ¥ d. B RL 0 d. B 1 VSWR ¥ Network Analyzer Basics DJB 12/96 na_basic. pre 23

Transmission Parameters V Incident V Transmitted DUT Transmission Coefficient = T = Insertion Loss (d. B) = - 20 Log VTransmitted V Incident V V Gain (d. B) = 20 Log V Trans V Inc Trans = tÐf = - 20 log t Inc = 20 log t Network Analyzer Basics DJB 12/96 na_basic. pre 24

Deviation from Linear Phase Use electrical delay to remove linear portion of phase response + Frequency Low resolution o o Phase 45 /Div (Electrical delay function) Deviation from linear phase Phase 1 /Div RF filter response Linear electrical length added yields Frequency High resolution Network Analyzer Basics DJB 12/96 na_basic. pre 25

What is group delay? Frequency w tg Group Delay Dw Phase Group Delay to f Df Group Delay (t g) Average Delay = = f w f f -d f dw -1 360 o Frequency * df df Deviation from constant group delay indicates distortion in radians/sec Average delay indicates transit time in degrees in Hz ( w = 2 p f ) Network Analyzer Basics DJB 12/96 na_basic. pre 26

Phase Why measure group delay? f f -d f dw Group Delay -d f dw f f Same p-p phase ripple can result in different group delay Network Analyzer Basics DJB 12/96 na_basic. pre 27

Low-Frequency Network Characterization H-parameters V 1 = h 11 I 1 + h 12 V 2 = h 21 I 1 + h 22 V 2 Y-parameters I 1 = y 11 V 1 + y 12 V 2 I 2 = y 21 V 1 + y 22 V 2 Z-parameters V 1 = z 11 I 1 + z 12 I 2 V 2 = z 21 I 1 + z 22 I 2 h 11 = V 1 I 1 V 2=0 (requires short circuit) h 12 = V 1 V 2 I 1=0 (requires open circuit) All of these parameters require measuring voltage and current (as a function of frequency) Network Analyzer Basics DJB 12/96 na_basic. pre 28

Limitations of H, Y, Z Parameters (Why use S-parameters? ) H, Y, Z parameters Hard to measure total voltage and current at device ports at high frequencies l Active devices may oscillate or self-destruct with shorts / opens l S-parameters Relate to familiar measurements reflection coefficient. . . ) l Relatively easy to measure l Can cascade S-parameters of multiple system performance l Analytically convenient l CAD programs èFlow-graph analysis (gain, loss, a 1 devices S 11 to. Reflected predict b 1 Transmitted b 2 DUT Port 2 Port 1 Transmitted è l S 21 Incident S 12 S 22 Reflected a 2 Incident b 1 = S 11 a 1 + S 12 a 2 b 2 = S 21 a 1 + S 22 a 2 Can compute H, Y, or Z parameters from S-parameters if desired Network Analyzer Basics DJB 12/96 na_basic. pre 29

Measuring S-Parameters a 1 Forward S Incident Z 0 S 11 b 1 S 21 = Transmitted Incident b 1 = a 1 b 2 = a 1 a 2 = 0 Z 0 S 12 = Transmitted Incident S 22 DUT Load Reflected Incident S 22 = a 1 = 0 b 1 Load DUT Reflected Incident S 11 = b 2 Transmitted 21 Incident b 1 = a 2 a 1 = 0 b 2 Reverse Reflected S 12 b 2 = a 2 Network Analyzer Basics DJB 12/96 na_basic. pre 30

Measuring Nonlinear Behavior Most common measurements: l Using a spectrum analyzer + source(s) harmonics, particularly second and third èintermodulation products resulting from two or more carriers l Using a network analyzer and power sweeps ègain compression RL 0 d. Bm èAM to PM conversion l Noise figure è 8563 A LPF SPECTRUM ANALYZER ATTEN 10 d. B / DIV 9 k. Hz - 26. 5 GHz DUT CENTER 20. 00000 MHz RB 30 Hz VB 30 Hz SPAN 10. 00 k. Hz ST 20 sec Network Analyzer Basics DJB 12/96 na_basic. pre 31

What is the difference between network and spectrum analyzers? Hard: getting (accurate) trace Easy: interpreting results . Easy: getting trace Hard: interpreting results Power Amplitude Ratio 8563 A Measures known signal Frequency Network analyzers: l l l measure components, devices, circuits, sub-assemblies contain source and receiver display ratioed amplitude and phase (frequency or power sweeps) SPECTRUM ANALYZER 9 k. Hz - 26. 5 GHz Measures unknown signals Frequency Spectrum analyzers: l l l measure signal amplitude characteristics (carrier level, sidebands, harmonics. . . ) are receivers only (single channel) can be used for scalar component test (no phase) with tracking gen. or ext. source(s) Network Analyzer Basics DJB 12/96 na_basic. pre 32

Agenda l l l Why do we test components? What measurements do we make? Network analyzer hardware Error models and calibration Typical measurements Advanced topics Network Analyzer Basics DJB 12/96 na_basic. pre 33

Generalized Network Analyzer Block Diagram Incident Transmitted DUT SOURCE Reflected SIGNAL SEPARATION INCIDENT (R) REFLECTED (A) TRANSMITTED (B) RECEIVER / DETECTOR PROCESSOR / DISPLAY H Network Analyzer Basics DJB 12/96 na_basic. pre 34

Source Supplies stimulus for system l Swept frequency or power l Traditionally NAs used separate source èOpen-loop VCOs èSynthesized sweepers l Most HP analyzers sold today have integrated, synthesized sources l Integrated, synthesized sources Network Analyzer Basics DJB 12/96 na_basic. pre 35

Signal Separation Measuring incident signals for ratioing 50 W 6 d. B l Splitter usually resistive ènon-directional èbroadband è 50 W 6 d. B l Main signal Coupled signal Coupler directional èlow loss ègood isolation, directivity èhard to get low freq performance è Network Analyzer Basics DJB 12/96 na_basic. pre 36

Signal Separation Separating incident and reflected signals l Coupler directional èlow loss ègood isolation, directivity èhard to get low freq performance è l Bridge used to measure reflected signals only èbroadband èhigher loss è Detector Test Port Network Analyzer Basics DJB 12/96 na_basic. pre 37

Forward Coupling Factor Coupling, forward -20 d. Bm. 01 m. W Source Z 0 -. 046 d. Bm. 99 m. W 0 d. Bm 1 m. W Example of 20 d. B Coupler Coupling Factor (d. B) = -10 log P coupling forward P incident Network Analyzer Basics DJB 12/96 na_basic. pre 38

Directional Coupler Isolation Coupling, reverse -50 d. Bm. 00001 m. W (Reverse Coupling Factor) this is an error signal during measurements Source Z 0 0 d. Bm 1 m. W -. 046 d. Bm. 99 m. W Example of 20 d. B Coupler "turned around" Isolation Factor (d. B) = -10 log Pcoupled reverse Pincident Network Analyzer Basics DJB 12/96 na_basic. pre 39

Directional Coupler Directivity (d. B) = 10 log Directivity = Pcoupled forward Pcoupled reverse Coupling Factor Isolation Directivity (d. B) = Isolation (d. B) - Coupling Factor (d. B) Example of 20 d. B Coupler with 50 d. B isolation: Directivity = 50 d. B - 20 d. B = 30 d. B Network Analyzer Basics DJB 12/96 na_basic. pre 40

Measuring Coupler Directivity the Easy Way 1. 0 (0 d. B) (reference) Good approximation for coupling factors ³ 10 d. B Coupler Directivity 35 d. B short Source . 018 (35 d. B) (normalized) Directivity = 35 d. B - 0 d. B = 35 d. B Source load Assume perfect load Network Analyzer Basics DJB 12/96 na_basic. pre 41

Interaction of Directivity with the DUT (Without Error Correctio 0 Device 30 Add in Phase 60 Device Frequency Directivity Return Loss Directivity Data Max DUT RL = 40 d. B Data Min Data = Vector Sum Directivity Cancel Data » 0 Network Analyzer Basics DJB 12/96 na_basic. pre 42

Directional Bridge l l 50 W l l 50 ohm load at test port balances the bridge - detector reads zero Extent of bridge imbalance indicates impedance Measuring magnitude and phase of imbalance gives complex impedance "Directivity" is difference between maximum and minimum balance Detector 50 W Test Port Network Analyzer Basics DJB 12/96 na_basic. pre 43

Incident Transmitted DUT Detector Types Reflected SOURCE SIGNAL SEPARATION INCIDENT (R) REFLECTED (A) TRANSMITTED (B) RECEIVER / DETECTOR Diode PROCESSOR / DISPLAY Scalar broadband (no phase information) DC RF AC Tuned Receiver RF IF = F LO ± F RF ADC / DSP IF Filter Scalar narrowband (magnitude only) Vector (magnitude and phase) LO Network Analyzer Basics DJB 12/96 na_basic. pre 44

Broadband Diode Detection Easy to make broadband l Inexpensive compared to tuned receiver l Good for measuring frequency-translating devices l Improve dynamic range by increasing power l Medium sensitivity / dynamic range l 10 MHz 26. 5 GHz Network Analyzer Basics DJB 12/96 na_basic. pre 45

Narrowband Detection - Tuned Receiver ADC / DSP Best sensitivity / dynamic range l Provides harmonic / spurious signal rejection l Improve dynamic range by increasing power, averaging l Trade off noise floor and measurement speed l 10 MHz decreasing IF bandwidth, or 26. 5 GHz Network Analyzer Basics DJB 12/96 na_basic. pre 46

Front Ends: Mixers Versus Sampler-based front end ADC / DSP S ADC / DSP Mixer-based front end Harmonic generator f frequency "comb" It is cheaper and easier to make broadband front ends using samplers instead of mixers Network Analyzer Basics DJB 12/96 na_basic. pre 47

Comparison of Receiver Techniques Broadband (diode) detection Narrowband (tuned- receiver) detection 0 d. B -50 d. B -100 d. B -60 d. Bm Sensitivity higher noise floor l false responses l < -100 d. Bm Sensitivity high dynamic range l harmonic immunity l Dynamic range = maximum receiver power - receiver noise floor Network Analyzer Basics DJB 12/96 na_basic. pre 48

Network Analyzer Basics DJB 12/96 na_basic. pre 49

Traditional Scalar Analyzer Traditional scalar system consists of processor/display and source Example: HP 8757 D l requires external detectors, couplers, bridges, splitters l good for low-cost microwave scalar applications RF R A B RF Detector Bridge Reflection R A DUT Detector Termination DUT Transmission Network Analyzer Basics DJB 12/96 na_basic. pre 50 B

Modern Scalar Analyzer Everything necessary for transmission and reflection measurements is internal! One-port (reflection) and response (transmission) calibrations Narrowband broadband detectors Large display Synthesized source Transmission/reflection test set Network Analyzer Basics DJB 12/96 na_basic. pre 51

Spectrum Analyzer / Tracking Generator RF in IF LO 8563 A SPECTRUM ANALYZER 9 k. Hz - 26. 5 GHz DUT Spectrum analyzer TG out DUT f = IF Tracking generator Key differences from network analyzer: l l l one channel -- no ratioed or phase measurements More expensive than scalar NA Only error correction available is normalization Poorer accuracy Small incremental cost if SA is already needed Network Analyzer Basics DJB 12/96 na_basic. pre 52

Modern Vector Analyzer Features: Synthesizer 15 MHz to 60 MHz MUX RF f Reference Test Set detector 300 k. Hz to 3 GHz Phase Lock DU T integrated source lsampler-based front end ltuned receiver lmagnitude and phase lvector-error correction l. T/R or S-parameter test sets l 996 k. Hz A S B S R S 4 k. Hz ADC CPU Display Digital Control Source Test Set Receiver Note: modern scalar analyzers like HP 8711/13 C look just like vector analyzers, but they don't display phase Network Analyzer Basics DJB 12/96 na_basic. pre 53

T/R Versus S-Parameter Test Sets Transmission/Reflection Test Set S-Parameter Test Set Source Transfer switch R R B A Port 1 Port 2 Fwd l l l Port 2 Port 1 Fwd DUT RF always comes out port 1 port 2 is always receiver response, one-port cal available B A l l l DUT Rev RF comes out port 1 or port 2 forward and reverse measurements two-port calibration possible Network Analyzer Basics DJB 12/96 na_basic. pre 54

Three Versus Four-Channel Analyzers Source Transfer switch R 1 R A A B B R 2 Port 1 Port 2 3 samplers 4 samplers l l cheaper l. TRL*, LRM* cal only lincludes: è HP 8753 D è HP 8720 D (std. ) more expensive ltrue TRL, LRM cal lincludes è HP 8720 D (opt. 400) è HP 8510 C Network Analyzer Basics DJB 12/96 na_basic. pre 55

Processor / Display Incident Transmitted DUT SOURCE Reflected SIGNAL SEPARATION H 50 MHz-20 GHz NETWORK ANALYZER ACTIVE CHANNEL ENTRY RESPONSE INCIDENT (R) REFLECTED (A) TRANSMITTED (B) STIMULUS R CHANNEL INSTRUMENT STATE RECEIVER / DETECTOR T HP-IB STATUS PROCESSOR / DISPLAY PORT 1 PORT 2 markers l limit lines l pass/fail indicators l linear/log formats l grid/polar/Smith charts l Network Analyzer Basics DJB 12/96 na_basic. pre 56 R L S

Internal Measurement Automation Simple: recall states More powerful: l Test sequencing available on HP 8753 / 8720 families èkeystroke recording èsome advanced functions è l IBASIC available on HP 8711 family èsophisticated programs ècustom user interfaces è ABCDEFGHIJKLMNOPQRSTUVWXYZ 0123456789 + - / * = < > ( ) & "" " , . / ? ; : ' [ ] 1 ASSIGN @Hp 8714 TO 800 2 OUTPUT @Hp 8714; "SYST: PRES; *WAI" 3 OUTPUT @Hp 8714; "ABOR; : INIT 1: CONT OFF; *WAI" 4 OUTPUT @Hp 8714; "DISP: ANN: FREQ 1: MODE SSTOP" 5 OUTPUT @Hp 8714; "DISP: ANN: FREQ 1: MODE CSPAN" 6 OUTPUT @Hp 8714; "SENS 1: FREQ: CENT 175000000 HZ; *WAI" 7 OUTPUT @Hp 8714; "ABOR; : INIT 1: CONT OFF; : INIT 1; *WAI" 8 OUTPUT @Hp 8714; "DISP: WIND 1: TRAC: Y: AUTO ONCE" 9 OUTPUT @Hp 8714; "CALC 1: MARK 1 ON" 10 OUTPUT @Hp 8714; "CALC 1: MARK: FUNC BWID" 11 OUTPUT @Hp 8714; "SENS 2: STAT ON; *WAI" 12 OUTPUT @Hp 8714; "SENS 2: FUNC 'XFR: POW: RAT 1, 0'; DET NBAN; *WAI" 13 OUTPUT @Hp 8714; "ABOR; : INIT 1: CONT OFF; : INIT 1; *WAI" 14 OUTPUT @Hp 8714; "DISP: WIND 2: TRAC: Y: AUTO ONCE" 15 OUTPUT @Hp 8714; "ABOR; : INIT 1: CONT ON; *WAI" 16 END Network Analyzer Basics DJB 12/96 na_basic. pre 57

HP Families of HF Vector Analyzers Microwave HP 8720 D family 40 GHz leconomical lfast, small ltest mixers, high- power amps l. S-parameter l RF HP 8712/14 C 3 GHz llow cost, fast lnarrowband broadband detection l. T/R test set only l HP 8510 C family l 110 GHz in coax pulse systems lantenna meas. l. Tx/Rx module test lhighest accuracy l 4 S-parameter display l HP 8753 D family 6 GHz l 52 C: T/R test set l 53 D: S-parameter lhighest RF accuracy l. Offset and harmonic RF sweeps l Network Analyzer Basics DJB 12/96 na_basic. pre 58

HP Families of LF Vector Analyzers LF HP E 5100 A/B HP 8751 A 300 MHz leconomical lfast, small ltest resonators, filters lparameter analysis l 500 MHz lfast list sweep limpedance matching l 4 trace display l Combination HP 4195 A 500 MHz lnetwork/spectrum/ impedance (option) l. DC output luser-defined functions l HP 4396 A 1. 8 GHz lnetwork/spectrum/ impedance (option) lfast, highest accuracy ltime-gated spectrum (option) l Network Analyzer Basics DJB 12/96 na_basic. pre 59

Agenda l l l Why do we test components? What measurements do we make? Network analyzer hardware Error models and calibration Typical measurements Advanced topics Why do we even need error-correction and calibration? It is impossible to make perfect hardware l. It would be extremely expensive to make hardware good enough to not require any error correction l Network Analyzer Basics DJB 12/96 na_basic. pre 60

Measurement Error Modeling Systematic errors l l l due to imperfections in the analyzer and test setup are assumed to be time invariant (predictable) can be characterized (during calibration process) and mathematically removed during measurements Random errors l l l vary with time in random fashion (unpredictable) cannot be removed by calibration main contributors: èinstrument noise (source phase noise, IF noise floor, etc. ) èswitch repeatability èconnector repeatability Drift errors l l l are due to instrument or test-system performance calibration has been done are primarily caused by temperature variation can be removed by further calibration(s) Errors: SYSTEMATIC Measured Data changing after a Unknown Device RANDOM DRIFT Network Analyzer Basics DJB 12/96 na_basic. pre 61

Systematic Measurement Errors R Directivity A B Crosstalk DUT Frequency response l l reflection tracking (A/R) transmission tracking (B/R) Source Mismatch Load Mismatch Six forward and six reverse error terms yields 12 error terms for two-port devices Network Analyzer Basics DJB 12/96 na_basic. pre 62

Types of Error Correction Two main types of error correction: l response (normalization) èsimple to perform èonly corrects for tracking errors èstores reference trace in memory, divided by memory l vector èrequires more standards èrequires an analyzer that can measure phase èaccounts for all major sources of systematic error then does data thru SHORT thru OPEN S 11 LOAD A S 11 M Network Analyzer Basics DJB 12/96 na_basic. pre 63

What is Vector-Error Correction? l l l Process of characterizing systematic error terms èmeasure known standards èremove effects from subsequent measurements. 1 -port calibration (reflection measurements) èonly 3 systematic error terms measured èdirectivity, source match, and reflection tracking Full 2 -port calibration (reflection and transmission measurements) 12 systematic error terms measured èusually requires 12 measurements on four known standards (SOLT) Some standards can be measured multiple times THRU is usually measured four times) Standards defined in cal kit definition file ènetwork analyzer contains standard cal kit definitions èCAL KIT DEFINITION MUST MATCH ACTUAL CAL KIT USED! è l l (e. g. , Network Analyzer Basics DJB 12/96 na_basic. pre 64

Reflection: One-Port Model l Ideal RF in l S 11 M S 11 A l Error Adapter If you know the systematic error terms, you can solve for the actual S-parameter Assumes good termination at port two if testing two-port devices If port 2 is connected to the network analyzer and DUT reverse isolation is low (e. g. , filter passband): èassumption of good termination is not valid ètwo-port error correction yields better results ED = Directivity 1 RF in ERT = Reflection tracking S 11 M ES ED S 11 A ES = Source Match S 11 M = Measured ERT S 11 M = ED + ERT S 11 A 1 - ES S 11 A = Actual To solve for S 11 A, we have 3 equations and 3 unknowns Network Analyzer Basics DJB 12/96 na_basic. pre 65

Before and After One-Port Calibration 0 2. 0 Data Before Error Correction Return Loss (d. B) 20 40 1. 01 Data After Error Correction 60 6000 VSWR 1. 1 1. 001 12000 Network Analyzer Basics DJB 12/96 na_basic. pre 66

Adapter Considerations reflection from adapter desired signal leakage signal r Coupler directivity = 40 d. B r total = adapter + Adapter DUT Termination r DUT has SMA (f) connectors APC-7 calibration done here Worst-case System Directivity 28 d. B 17 d. B 14 d. B Adapting from APC-7 to SMA (m) SWR: 1. 06 APC-7 to N (f) + N (m) to SMA (m) SWR: 1. 05 SWR: 1. 25 APC-7 to N (m) + N (f) to SMA (f) + SMA (m) to (m) SWR: 1. 05 SWR: 1. 25 SWR: 1. 15 Network Analyzer Basics DJB 12/96 na_basic. pre 67

Two-Port Error Correction Port 1 a 1 ED ES ERT ED = Directivity ES = Source Match ERT = Reflection Tracking l l Port 2 S 21 ETT A S 11 A b 1 l EX S 22 A EL b 2 Forward model a 2 S 12 A EL = Load Match ETT = Transmission Tracking EX = Isolation Notice that each actual S-parameter is a function of all four measured S-parameters Analyzer must make forward and reverse sweep to update any one S-parameter Luckily, you don't need to know these equations to use network analyzers!!! Network Analyzer Basics DJB 12/96 na_basic. pre 68

Crosstalk (Isolation) Crosstalk definition: signal leakage between ports l. Can be a problem with: è High-isolation devices (e. g. , switch in open position) è High-dynamic range devices (some filter stopbands) l. Isolation calibration è Adds noise to error model (measuring noise floor of system) è Only perform if really needed (use averaging) è if crosstalk is independent of DUT match, use two terminations è if dependent on DUT match, use DUT with termination on output l DUT Isolation cal when crosstalk is dependent on match of DUT LOAD Network Analyzer Basics DJB 12/96 na_basic. pre 69

Errors and Calibration Standards UNCORRECTED DUT RESPONSE 1 -PORT thru Convenient l. Generally not accurate l. No errors removed l Easy to perform l. Use when highest accuracy is not required l. Removes frequency response error Random (Noise, Repeatability) Drift SHORT OPEN LOAD DUT l Other errors: FULL 2 -PORT For reflection measurements l. Need good termination for high accuracy with two-port devices l. Removes these errors: Directivity Source match Reflection tracking thru l DUT Highest accuracy l. Removes these errors: Directivity Source, load match Reflection tracking Transmission tracking Crosstalk l Network Analyzer Basics DJB 12/96 na_basic. pre 70

ECal: Electronic Calibration 85060 series) (HP H Impedance States l achieved by shunting transmission line with PIN-diode switches in various combinations l 13 reflective states, from low to high reflection l two thru states plus one isolation state l programmable and highly repeatable l characterized by TRL-calibrated network analyzer Calibration l four known impedance states presented at each frequency (providing redundant information) l uses least-squares fit to calculate error terms l yields accuracy between SOLT and TRL HP 85062 A Electronic Calibration Module 0. 045 - 2 GHz 12 7 1 5 Example distribution of impedance states for reflection calibration at one frequency Network Analyzer Basics DJB 12/96 na_basic. pre 71

Calibration Summary Reflection Test Set (cal type) T/R (one-port) S-parameter SHORT (two-port) OPEN Reflection tracking l Directivity l Source match l Load match l LOAD Test Set (cal type) Transmission error can be corrected error cannot be corrected * HP 8711 C enhanced response cal can correct for source match during transmission measurements Transmission Tracking l Crosstalk l Source match l Load match T/R (response, isolation) S-parameter (two-port) l ( *) Network Analyzer Basics DJB 12/96 na_basic. pre 72

Reflection Example Using a One-Port Cal Analyzer port 2 match: 18 d. B (. 126) DUT 16 d. B RL (. 158) 1 d. B loss (. 891) Measurement uncertainty: -20 * log (. 158 +. 100) = 11. 4 d. B (-4. 6 d. B) -20 * log (. 158 -. 100) = 24. 7 d. B (+8. 7 d. B) . 158 (. 891)(. 126)(. 891) =. 100 Low-loss bidirectional devices generally require 2 -port calibration for low measurement uncertainty Network Analyzer Basics DJB 12/96 na_basic. pre 73

Transmission Example Using Response Cal RL = 18 d. B (. 126) RL = 14 d. B (. 200) Thru calibration (normalization) builds error into measurement due to source and load match interaction Calibration Uncertainty = (1 ± r r ) S L = (1 ± (. 200)(. 126) = ± 0. 22 d. B Network Analyzer Basics DJB 12/96 na_basic. pre 74

Transmission Example (continued) Source match = 14 d. B (. 200) DUT 1 d. B loss (. 891) 16 d. B RL (. 158) Load match = 18 d. B (. 126) 1 (. 126)(. 158) =. 020 (. 126)(. 891)(. 200)(. 891) =. 020 (. 158)(. 200) =. 032 Total measurement uncertainty: +0. 60 + 0. 22 = +0. 82 d. B -0. 65 - 0. 22 = - 0. 87 d. B Measurement uncertainty = 1 ± (. 020+. 032) = 1 ±. 072 = + 0. 60 d. B - 0. 65 d. B 75 Network Analyzer Basics DJB 12/96 na_basic. pre

Measuring Amplifiers with a Response Cal Source match = 14 d. B (. 200) DUT 16 d. B RL (. 158) Load match = 18 d. B (. 126) 1 (. 126)(. 158) =. 020 (. 158)(. 200) =. 032 Total measurement uncertainty: +0. 44 + 0. 22 = + 0. 66 d. B -0. 46 - 0. 22 = - 0. 68 d. B Measurement uncertainty = 1 ± (. 020+. 032) = 1 ±. 052 = + 0. 44 d. B - 0. 46 d. B Network Analyzer Basics DJB 12/96 na_basic. pre 76

Transmission Measurements using the Enhanced Response Calibration Uncertainty = (1 ± r r ) L S Effective source match = 35 d. B! Source match = 35 d. B (. 0178) DUT 1 d. B loss (. 891) 16 d. B RL (. 158) = (1 ± (. 0178)(. 126) = ±. 02 d. B Load match = 18 d. B (. 126) 1 Measurement (. 126)(. 158) =. 020 uncertainty =1± (. 126)(. 891)(. 0178)(. 891) =. 0018 (. 020+. 0018+. 0028) = 1 ±. 0246 (. 158)(. 0178) =. 0028 = + 0. 211 d. B - 0. 216 Total measurement uncertainty: 0. 22 +. 02 = ± 0. 24 d. B Network Analyzer Basics DJB 12/96 na_basic. pre 77

Calculating Measurement Uncertainty After a Two-Port Calibration DUT 1 d. B loss (. 891) 16 d. B RL (. 158) Corrected error terms: (8753 D 1. 3 -3 GHz Type-N) Directivity = 47 d. B Source match = 36 d. B Load match = 47 d. B Refl. tracking =. 019 d. B Trans. tracking =. 026 d. B Isolation = 100 d. B Reflection uncertainty 2 S 11 m = S 11 a ± (E D+ S 11 a E S+ S 21 a. S 12 a. E L+ S 11 a. E RT) =. 158 ± (. 0045+. 158 2*. 0158 +. 891 2*. 0045 +. 158*. 0022) =. 158 ±. 0088 = 16 d. B +0. 53 d. B, -0. 44 d. B Transmission uncertainty S 21 m = S 21 a ± (E I + S 11 a. E S+ S 22 a. E L+ S 21 a. S 12 E ) a E a TT S + L S 21 E 2 =. 891 ± (10 -6+. 158*. 0158 +. 158*. 0045 +. 891 *. 0158*. 0045 +. 891*. 003) =. 891 ±. 0059 = 1 d. B ± 0. 06 d. B Network Analyzer Basics DJB 12/96 na_basic. pre 78

Response versus Two-Port Calibration Measuring filter insertion loss CH 1 S 21&M log MAG CH 2 MEM log MAG Cor 1 d. B/ REF 0 d. B After 2 -port calibration After response calibration Uncorrected Cor x 2 1 START 2 000 MHz STOP 6 000 MHz 2 Network Analyzer Basics DJB 12/96 na_basic. pre 79

Thru-Reflect-Line (TRL) Calibration We know about Short-Open-Load-Thru (SOLT) calibration. . . What is TRL? l A two-port calibration technique l Good for noncoaxial environments (waveguide, fixtures, wafer probing) l Uses the same 12 -term error model as the more common SOLT cal l Uses practical calibration standards that fabricated and characterized l Two variations: TRL (requires 4 samplers) three samplers needed) l Other variations: Line-Reflect-Match (LRM), Thru-Reflect-Match (TRM), plus many others H are easily and TRL* (only Network Analyzer Basics DJB 12/96 na_basic. pre 80

Why Are Four Samplers Better Than Three? TRL* HP 8720 D Opt. 400 adds fourth sampler, allowing full TRL calibration l TRL* assumes the source and load match of a test port are equal forward and reverse measurements) èthis is only a fair assumption for a three-sampler network analyzer èTRL* requires ten measurements to quantify eight unknowns è l TRL (port symmetry between Four samplers are necessary for all the measurements required for a full TRL cal (fourteen measurements to quantify ten unknowns) èTRL and TRL* use identical calibration standards In noncoaxial applications: èTRL achieves better source match and load match correction than TRL* What about coaxial applications? èTRL* and SOLT calibration have about the same accuracy èCoaxial TRL is usually more accurate than SOLT but not commonly used è l l Network Analyzer Basics DJB 12/96 na_basic. pre 81

Calibrating Non-Insertable Devices When doing a thru cal, normally test ports mate directly l cables can be connected directly without an adapter l result is a zero-length thru What is an insertable device? l has same type of connector, but different sex on each port l has same type of sexless connector on each port (e. g. APC-7) What is a non-insertable device? l one that cannot be inserted in place of a zero-length thru l has same connectors on each port (type and sex) l has different type of connector on each port one port, coaxial on the other) What calibration choices do I have for non-insertable devices? l Use an uncharacterized thru adapter l Use a characterized thru adapter (modify cal-kit definition) l Swap equal adapters l Adapter removal (e. g. , waveguide on DUT Network Analyzer Basics DJB 12/96 na_basic. pre 82

Swap Equal Adapters Method Port 1 Adapter A Port 1 Port 2 DUT Accuracy depends on how well the adapters are matched loss, electrical length, match and impedance should all be equal 1. Transmission cal using adapter A. Port 2 Adapter B Port 2 2. Reflection cal using adapter B. Adapter B Port 2 3. Measure DUT using adapter B. Network Analyzer Basics DJB 12/96 na_basic. pre 83

Adapter Removal Calibration l l l In firmware of HP 8510 family Can be accomplished with E-Cal (HP 85060) and HP 8753/8720 families Uses adapter with same connectors as DUT Adapter's electrical length must be specified within 1/4 wavelength èadapters supplied with HP type-N, 3. 5 mm, and 2. 4 mm cal kits are already defined èfor other adapters, measure electrical length and modify cal-kit definition Calibration is very accurate and traceable See Product Note 8510 -13 for more details Port 1 DUT Port 2 Port 1 Cal Adapter Port 2 B 1. Perform 2 -port cal with adapter on port 2. Save in cal set 1. Adapter Port 2 B 2. Perform 2 -port cal with adapter on port 1. Save in cal set 2. Cal Set 1 Port 1 Cal Adapter Cal Set 2 [CAL] [MORE] [MODIFY CAL SET] [ADAPTER REMOVAL] Port 1 DUT Adapter Port 2 B 3. Use ADAPTER REMOVAL to generate new cal set. 4. Measure DUT without cal adapter. Network Analyzer Basics DJB 12/96 na_basic. pre 84

Agenda l l l Why do we test components? What measurements do we make? Network analyzer hardware Error models and calibration Typical measurements Advanced topics Network Analyzer Basics DJB 12/96 na_basic. pre 85

Frequency Sweep - Filter Test CH 1 S 21 log MAG 10 d. B/ CH 1 S 11 REF 0 d. B log MAG REF 0 d. B 5 d. B/ Cor Stopband rejection 69. 1 d. B START. 300 000 MHz STOP 400. 000 MHz CH 1 S 21 log MAG Cor CENTER 200. 000 MHz 1 d. B/ SPAN 50. 000 MHz REF 0 d. B Return loss 1 m 1: 4. 000 GHz -0. 16 d. B m 2 -ref: 2. 145 234 GHz 0. 00 d. B ref Insertion loss 2 Cor START 2 000 MHz x 2 1 STOP 6 000 MHz 2 Network Analyzer Basics DJB 12/96 na_basic. pre 86

Output Power (d. Bm) Power Sweep - Compression Saturated output power Compression region Linear region (slope = small-signal gain) Input Power (d. Bm) Network Analyzer Basics DJB 12/96 na_basic. pre 87

Power Sweep -Gain Compression CH 1 S 21 1 og MAG 1 d. B/ REF 32 d. B 30. 991 d. B 12. 3 d. Bm C 2 1 d. B compression: input power resulting in 1 d. B drop in gain l Ratioed measurement l Output power available (non-ratioed measurement) 0 0 IF BW 3 k. Hz START -10 d. Bm CW 902. 7 MHz SWP 420 msec STOP 15 d. Bm Network Analyzer Basics DJB 12/96 na_basic. pre 88

Power Sweep - AM to PM Conversion 1: Transmission Log Mag 2: Transmission /M Phase 1. 0 d. B/ 5. 0 deg/ Ref 21. 50 d. B Ref -115. 7 deg Ch 1: Mkr 1 -4. 50 d. Bm 20. 48 d. B Ch 2: Mkr 2 1. 00 d. B 0. 86 deg Use transmission setup with a power sweep l. Display phase of S 21 l. AM - PM = 0. 86 deg/d. B l 2 1 Start -10. 00 d. Bm CW 900. 000 MHz Stop 0. 00 d. Bm 1 Network Analyzer Basics DJB 12/96 na_basic. pre 89

Agenda l l l Why do we test components? What measurements do we make? Network analyzer hardware Error models and calibration Typical measurements Advanced topics è Time domain è Frequency-translating devices è High-power amplifiers è Multiport devices è In-fixture measurements è Crystal Resonators è Balanced-Cables Network Analyzer Basics DJB 12/96 na_basic. pre 90

Time-Domain Reflectometry (TDR) Analyze impedance versus time l Differentiate inductive and capacitive transitions l High-speed oscilloscope: èyields fast update rate è 200 m. V step typical l Network analyzer: èbroadband frequency sweep (often requires microwave VNA) èinverse FFT to compute time-domain èresolution inversely proportional to frequency span l non-Zo termination inductive transition Zo capacitive transition Network Analyzer Basics DJB 12/96 na_basic. pre 91

Time-Domain Gating l l TDR and gating can remove undesired reflections (a form of error correction) Only useful for broadband devices (a load or thru for example) Define gate to only include DUT CH 1 S 11&M log MAG 5 d. B/ REF 0 d. B Use two-port calibration PRm Cor CH 1 MEM Re PRm Cor RISE TIME 29. 994 ps 8. 992 mm 2 20 m. U/ REF 0 U 1: 48. 729 m. U 638 ps Gate 1: -45. 113 d. B 0. 947 GHz 2: -15. 78 d. B 6. 000 GHz 2: 24. 961 m. U 668 ps 1 3: -10. 891 m. U 721 ps 2 3 Thru in time domain CH 1 START 0 s STOP 1. 5 ns 1 Thru in frequency domain, with and without gating START. 050 000 GHz STOP 20. 050 000 GHz Network Analyzer Basics DJB 12/96 na_basic. pre 92

Time-Domain Transmission RF Input RF Output CH 1 S 21 log MAG 15 d. B/ REF 0 d. B Main Wave Surface Wave Leakage Triple Travel Cor CH 1 S 21 log MAG 10 d. B/ REF 0 d. B RF Leakage Triple Travel Cor Gate off Gate on START -1 us STOP 6 us Network Analyzer Basics DJB 12/96 na_basic. pre 93

Frequency-Translating Devices Medium-dynamic range measurements (35 d. B) R IN 2 1 ACTIVE CHANNEL ENTRY RESPONSE HP 8753 D start: MHz stop: MHz 900 650 FIXED LO: 1 GHz LO POWER: 13 d. Bm start: MHz stop: MHz R CHANNEL INSTRUMENT STATE STIMULUS Ref In 100 Reference Mixer R HP-IB STATUS 350 H Ref Out PROBE POWER FUSED 8753 D 30 KHz-3 GHz NETWORK ANALYZER PORT 1 PORT 2 L T RF 10 d. B S IF LO 10 d. B CH 1 CONV MEAS log MAG 10 d. B/ REF 10 d. B LO DUT 3 d. B Signal Generator START 640. 000 MHz STOP 660. 000 MHz High-dynamic range measurements Network Analyzer Basics DJB 12/96 na_basic. pre 94 Lowpass Filter

High-Power Amplifiers Preamp ACTIVE CHANNEL ENTRY RESPONSE Ref In STIMULUS INSTRUMENT STATE R CHANNEL R HP-IB STATUS H PROBE POWER FUSED 8753 D 30 KHz-3 GHz NETWORK ANALYZER PORT 1 PORT 2 HP 8753 D L T S Source Preamp AUT DUT R B A AUT +43 d. Bm max input (20 watts!) HP 8720 D Option 085 HP 85118 A High-Power Amplifier Test System Network Analyzer Basics DJB 12/96 na_basic. pre 95

Multiport Device Test Port 1 Port 2 Port 3 Port 2 Note: unused ports are terminated PR m Co r CH 1 S 21 CH 2 S 12 log MAG 10 10 d. B/ REF 0 REF d. B 0 d. B 1_ -1. 9248 1_ -1. 2468 d. B 839. 470 000 d. B MHz 1 Hl d Directional Coupler Multiport test sets: limprove throughput by reducing the number of connections to DUTs with more than 2 ports lallow simultaneous viewing of two paths (good for tuning duplexers) linclude mechanical or solid-state switches, 50 or 75 ohms ldegrade raw performance so calibration is a must (use two-port cals whenever possible) Duplexer Test - Tx-Ant and Ant-Rx 1 Test Set PAS S 1 880. 435 000 MHz PR m Co r 2 Hl d PAS S CH 1 START 775. 000 CH 2 MHz START 775. 000 MHz STOP 925. 000 000 MHz Network Analyzer Basics DJB 12/96 na_basic. pre 96

In-Fixture Measurements Measurement problem: coaxial calibration plane is not the same as the in-fixture measurement plane Measurement Plane Calibration Plane Fixture ED ES ET Error correction with coaxial calibration DUT Loss l Phase shift l Mismatch l Network Analyzer Basics DJB 12/96 na_basic. pre 97

Characterizing Crystal Resonators/Filters Ch 1 Z: R phase 40 / REF 0 1: 15. 621 U 31. 998 984 925 MHz Min Cor 1 START 31. 995 MHz SEG START DUT STOP POINTS STOP 32. 058 MHz POWER IFBW 1 31. 995 MHz 32. 008 MHz 200 0 d. Bm 200 Hz > 2 32. 052 MHz 32. 058 MHz 200 0 d. Bm 200 Hz END Example of crystal resonator measurement HP E 5100 A Network Analyzer Basics DJB 12/96 na_basic. pre 98

RF Balanced-Cable Measurements 280. 00 ohm 260. 00 ohm 240. 00 ohm 220. 00 ohm 200. 00 ohm 180. 00 ohm 160. 00 ohm 140. 00 ohm 120. 00 ohm 100. 00 ohm 80. 00 ohm 0. 01 MHz 0. 10 MHz 1. 00 MHz 1000. 00 MHz Example of characteristic impedance (Zc) measurement from 10 k. Hz to 500 MHz 0. 00 d. B -20. 00 d. B -40. 00 d. B -60. 00 d. B -80. 00 d. B -100. 00 d. B HP 4380 S RF Balanced-Cable Test System -120. 00 d. B -140. 00 d. B 0. 01 MHz 0. 10 MHz 1. 00 MHz 1000. 00 MHz Example of near-end crosstalk (NEXT) measurement Network Analyzer Basics DJB 12/96 na_basic. pre 99

Challenge Quiz 1. Can filters cause distortion in communications systems? A. Yes, due to impairment of phase and magnitude response B. Yes, due to nonlinear components such as ferrite inductors C. No, only active devices can cause distortion D. No, filters only cause linear phase shifts E. Both A and B above 2. Which statement about transmission lines is false? A. Useful for efficient transmission of RF power B. Requires termination in characteristic impedance for low VSWR C. Voltage is independent of position along line D. Used when wavelength of signal is small compared to length of line E. Can be realized in a variety of forms such as coaxial, waveguide, microstrip 3. Which statement about narrowband detection is false? A. Is only available in vector network analyzers B. Provides much greater dynamic range than diode detection C. Uses variable-bandwidth IF filters to set analyzer noise floor D. Provides rejection of harmonic and spurious signals E. Uses mixers or samplers as downconverters Network Analyzer Basics DJB 12/96 na_basic. pre 100

Challenge Quiz (continued) 4. Maximum dynamic range with narrowband detection is defined as: A. Maximum receiver input power minus the stopband of the device under test B. Maximum receiver input power minus the receiver's noise floor C. Detector 1 -d. B-compression point minus the harmonic level of the source D. Receiver damage level plus the maximum source output power E. Maximum source output power minus the receiver's noise floor 5. With a T/R analyzer, the following error terms can be corrected: A. Source match, load match, transmission tracking B. Load match, reflection tracking, transmission tracking C. Source match, reflection tracking, transmission tracking D. Directivity, source match, load match E. Directivity, reflection tracking, load match 6. Calibration can remove which of the following types of measurement error? A. Systematic and drift B. Systematic and random C. Random and drift D. Repeatability and systematic E. Repeatability and drift Network Analyzer Basics DJB 12/96 na_basic. pre 101

Challenge Quiz (continued) 7. Which statement about TRL calibration is false? A. Is a type of two-port error correction B. Uses easily fabricated and characterized standards C. Most commonly used in noncoaxial environments D. Is not available on the HP 8720 D family of microwave network analyzers E. Has a special version for three-sampler network analyzers 8. For which component is it hardest to get accurate transmission and reflection measurements when using an 8711 B scalar network analyzer? A. Amplifiers because output power causes receiver compression B. Cables because load match cannot be corrected C. Filter stopbands because of lack of dynamic range D. Mixers because of lack of broadband detectors E. Attenuators because source match cannot be corrected 9. Power sweeps are good for which measurements? A. Gain compression B. AM to PM conversion C. Saturated output power D. Power linearity E. All of the above Network Analyzer Basics DJB 12/96 na_basic. pre 102