We go whereyou go with lab qualityspectrum analysis.

492/492P Spectrum Analyzers

Lab quality you can get a handle on.

Fully calibrated inamplitude and frequency.Crt readout of parameters.Reference level, center fre-quency, vertical scale factor,frequency span, frequencyrange, resolution bandwidth,and rf attenuation are dis-played right on the screenfor easy reference andphotographic documenta-tion. Convenient bezel iden-tification of crt parameters.Programmable control set-tings and signal display in-formation are available viaGPIBinthe492R80 dB dynamic range.Wide frequency range.50 kHz to 21 GHz internallyand to 60 GHz with Tektronixcalibrated externalwaveguide mixers. Opera-tion to 220 GHz with com-mercially available externalwaveguide mixers.Automatic modes.Wide range of options.Goes where you go.With its portable form factorand single-handle carry, the492 moves easily around thelab or systems test area, fitsunder an airplane seat, orgoes out with you on a fieldcall.Environmentalized perMIL-T-28800B.

Copyright ©1980, Tektronix, Inc. All rights reserved.

Full programmability.492P model provides IEEE488 compatibility via GPIBinterface bus. Allows fullprogramming of all signal-affecting front-panel controlsettings and processing ofstored spectrum displays.Digital storage and signalprocessing.SAVE A, B MINUS SAVE A,MAX HOLD, and AVERAGEmodes. Lets you compare,subtract, save maximumvalues, or noise average(smooth) your spectrumdisplays.Microprocessor aidedease of operation.Simple three-knob operationperforms your measure-ments quickly and easily:

1-Set center frequency,2-Set span/div,3-Set reference level.

Automatic control on mostoften used functions.Power-on initiates inputprotection and normalstart-up settings.Input protection.Freedom from spuriousresponses.Internal calibrated YIG pre-selector available with Op-tion 01. Eliminates harmonicmixing products and im-ages, and increasesdynamic range for harmonicmeasurements in the micro-wave range.

A spectrum analyzer with unmatchedconvenience and capability.In one compact package.

Simple to use.Operation of the 492 is aseasy as 1 (set the input ref-erence level), 2 (set thecenter frequency), and 3(set the frequency span).

Most-used functions areautomatically controlled.Setting the reference levelautomatically selects theproper // gain and rf attenu-ation. Setting the span/divautomatically selects theproper resolution and scantime. These preprogrammedcontrols of interrelated func-tions save you time andsimplify your measurementtask.

The center frequency con-trol with constant tuning rate(CTR) provides smooth fre-quency adjustment with justone knob regardless of thespan being used. CTRallows the operator to posi-tion a signal more quicklyand more precisely than aconventional tuning system.

Digital storage and signalprocessing.Digital storage allows forflicker-free, easy to interpretdisplays that may be held inmemory as long as instru-ment power is on.Available as Option 02,digital storage and signal

processing enhance the492's performance andease of operation.VIEW A, VIEWS modes —Contents of the selectedmemory are displayed. All

stored displays are updatedcontinually (except withSAVE A mode). A and Bmemories can be combinedfor high resolution (1000point) storage.

SAVE A mode.

SAVE A mode — The spec-trum stored in memory A isdisplayed. If VIEWS modeis selected at the same time,memory A and B are bothdisplayed simultaneously forcomparison (data viewed inmemory B is updated con-tinuously).

B MINUS SAVE A mode —SAVE A is automatically ac-tivated and the algebraicdifference of the continu-ously updated contents ofmemory B and the storedcontents of memory A isdisplayed. Positive andnegative differences aredisplayed above and belowan internally selectable zeroreference screen position.

MAX HOLD mode.

MAX HOLD mode —thememory stores the highestamplitude signal detectedfor each frequency display,allowing you to maintain andmonitor maximum values.This feature is especiallyuseful in measuring signaldrift and stability, in record-ing peak amplitudes, and inlogging the presence ofrandom signals.

AVERAGE mode — Move-able cursor sets the level ofsignal peak detection or av-eraging. All signals abovethe cursor are peak de-tected and then digitallystored; all signals below thecursor are averaged beforestorage.

Portable form factor.Compact size and lightweight combine to offer un-matched portability in a lab-oratory quality analyzer. The492 can easily be moved inthe design lab or systemstest area — or wherever elseyou need it. It even fits underan airplane seat.Wide frequency range.The 492 offers unequalledfrequency coverage. From50 kHz to 220 GHz, withamplitude calibratedwaveguide mixers to60 GHz available from Tek-tronix. A broader range thanany laboratory analyzer andwith the performance youneed to handle tough labo-ratory measurements.

Wide frequency range.

Programmability/IEEE(GPIB) compatibility.The programmability andinterface bus capabilityavailable with the 492P pro-vide added measurementversatility.Repetitive or large quantitydata collection with consis-tent and rapid results ismade easy, as is recordingof data in hard copy form.Automated testing andmonitoring are also possi-ble. The GPIB interface en-ables full program control offront panel settings and ofspecial modes like12 dB/div and "smart" func-tions. When an externalcontroller is used, auto-mated data correction andanalysis can enhance re-sults and make possiblecomplex measurementssuch as total harmonic dis-tortion and power spectraldensity.

Amplitude resolution of0.25 dB.High amplitude accuracy ispossible through 0.25 dBsteps, an improvement overthe well-known if substitutiontechnique. Superfine 0.25dB control increments pro-vide 0.05 dB per 0.25 dBstep accuracy. This per-formance increase isachieved without a separatevernier control.

?

!

FINE

492P makes spectrum analysisautomatic. And easy.

Two instruments in one.The 492P is a fully program-mable version of the 492Spectrum Analyzer. It incor-porates all of the 492's labquality performance andease of use features whenused as a manual instrument.Push the "Reset to Local"

GPIB ADDRESS

1

button and the 492P be-comes a 492—with operationfrom the front panel. But, mostimportant, the 492P opensthe way to automated spec-trum analysis and documen-tation via its IEEE-488 (GPIB)interface.This versatility makes the492P useful in many applica-tions in the lab, factory orfield.With or without a controller.Switches on the rear panelselect the mode of operationas a GPIB instrument. In thenormal TALKER/LISTENERmode, the 492P listens to andexecutes commands from aGPIB controller. All importantfront panel settings can be

LF OR EOITALK ONLYLISTEN ONLY

EOI————- • '

operated remotely. Somefunctions are controlled withmore detail through the busthan possible from the frontpanel. For example, SPANcan be set with two digit pre-cision anywhere within therange of the instrument,making possible specialspans such a 4.8 kHz per div.Also, via the GPIB, the verticalscale may be set for 1 to 15dB per division in 1 dB incre-ments. When requested, the492P will report instrumentsettings, internal status ordata from its display.For field use where a con-troller is not available, the492P can be set to the TALKONLY or LISTEN ONLYmodes. In the TALK ONLYmode, it outputs waveformsand front panel settings in afixed format for data loggingto a digital tape, such as theTektronix 4924. In the LISTENONLY mode, the 492P be-comes a display for waveformdata sent on the bus and willrespond to commands formeasurement setup.

When used with the Tektronix 4052 Graphic Computing Systemcontroller and 4631 Hard Copy Unit, the 492P can provide testresults in both graphic and numeric form for the evaluation ofmicrowave signal sources.

Easy to use.The 492P is designed forease of operation via theGPIB, just as the 492 isdesigned for front paneloperational ease. Most com-mands for program controlare simply abbreviations ofthe front panel nomenclature.For example, to set centerfrequency, send the ASCIIcharacters "FREQ 5.2 GHz."To query the center fre-quency, send "FREQ?" Theresponse is "FREQ 5.2 E+ 09!'The 492P's high levelcommand language and thesimilarity of commands andresponses simplify pro-gramming and make pro-gram listings easily readablefor editing.Automated setup.The 492P is not only anobedient servant under pro-gram control, but smartenough to do many things onits own. For example, it willprovide all of its settings withone command. Just send"SET?" You'll get back a blockof characters listing all of thefront panel and internal set-tings. Store this response inthe controller or on a tape file.To return the 492P to theoriginal measurement condi-tion, send the same charac-

ters back to the analyzer. Toinitialize the 492P to its"power on" settings, send"INirInternal processingsimplifies programming.The 492P's power reducesprocessing time and easesthe software developmenttask. For example, the 492Pcan identify all signal peaksabove a specified amplitudethreshold and the maximumand minimum points on thedisplay waveform.Having identified a point ofinterest in its digital storagememory, the 492P can thenperform certain operationsautomatically. It can tune tocenter a signal on the dis-play before narrowing thespan. Send the command,"CENSIG" and it's doneautomatically. Another com-mand, "TOPSIG" automati-cally changes the sensitivityso the signal peaks at the topof the screen reference level.The display now reads di-rectly in dB below the signalpeak and assures an onscreen display for precisionamplitude measurements.

Programmable 492P saves time andsimplifies your job

A UHF TV signal with multiburst test pattern is acquired by the492P Programmable Spectrum Analyzer, sent via the GPIB indigital form and then displayed on the 4052 Graphic System.

FREO SPAN/DIVS3BKHZ/

VERT DISPLAY RF ATTEN FREQ RANGE RES BANDWIDTHI0DB/ 20DB 0-1.8 100 KHZ

The same spectrum displayed above is drawn by the 4052using the Tektronix 4662 Interactive Digital Plotter for highresolution documentation.

Automated signal tracking.Keeping a drifting signal onscreen in a narrow frequencyspan per division is no longertroublesome. With the internalprocessing functions and theability to repetitively executeinstructions in its input buffer,the 492P can track driftingsignals with virtually no helpfrom the controller.Auto peaking.Automatic peaking providesgreatest accuracy whenmeasuring at widely differingfrequencies using the op-tional internal preselector filter(1.8-21 GHz). Send "PEAKAUTO" from the controller tothe 492P and an internalroutine automatically adjuststhe preselector tracking formaximum signal response.Enhanced datapresentation via GPIB.Displayed waveforms can beoutputted from digital storageto a calculator, computer, ordata storage device such asa tape or disc file. The datamay be graphed on a digitalplotter, lower left, or displayedon the screen of a controllersuch as the BASIC-languageprogrammable Tektronix 4052Graphic System, top left.Mathematical operationssuch as calibration and cor-rection of the original datacan be performed in the con-troller. Data can be combinedfrom several different fre-quency spans to make a

composite plot. Raw data canbe converted into differentunits such as micro-volts ordBc. The two-way communi-cation ability of the 492Ppermits a real time compari-son of a controller-generatedspectrum, or set of limits, andan incoming signal on the492R The computationalpower of the controller canbe used to solve complexanalytical measurementssuch as total harmonic distor-tion, photos at top of page 9(facing) or power spectraldensity.

Full programmabilitycompletes the task.Complete automation of theentire measurement savestime and eliminates manyoperator errors or inconsis-tencies. Also, some pro-grammed measurementsmay be made more preciselyand thoroughly than bymanual methods. For a totalharmonic distortion meas-urement, for example, theanalyzer can be controlled totune each harmonic fre-quency separately, permittingan enlarged high resolutiondisplay of the signal peaks,lower left, page 9. After thepeak amplitude is measured,the span can be widened andthe analyzer tuned to find thenext harmonic. Internal pro-cessing greatly simplifies thecontrolling program andspeeds the measurement.

A 100 MHz signal and its harmonics displayed on the 492P witha ful l screen span of 500 MHz.

FREQUENCY

1.0E+82.0E+33.0E+84.0E+85.8E+86.8E+87.0E+88.0E+8

AMPLITUDE DBM

-2B.8-25.64-34.96-33.16-28.32-37.64-39.B8-33-43.56

RELATIVE DB

-4.84-14.16-17.36-7.52-16.84-18.28-14.2-22.76

TOTAL HARMONIC DISTORTION EQUALS 80 PERCENT

DO YOU MAHT TO DO ANOTHER ANALYSIS (YES OR H0>?

Automated total harmonic distortion test results computed bythe Tektronix 4052 and outputted on the Tektronix 4631 HardCopy Unit.

Full programmability allows tuning to each harmonic frequencyand measuring the signal peak with high amplitude resolution.Internal processing commands in the 492P greatly simplify thismeasurement.

Put it to work.With the programmable 492Pon your measurement team,repetitive measurements canbe done the same way everytime. Your throughput willincrease—and your confi-dence in results. And, theinternal processing and highlevel programming languagemake software developmentfaster. You get high power re-sults with easy programming.

When you look at the totalperformance capability of the492R you'll recognize itsvalue: Ease of operation bothas a programmable andmanual instrument. Wide fre-quency range. The versatilityto go where you go. Into thelab for automated testing; intothe field for data collection.

Check the specs and see.

Frequency RelatedFrequency Range — 50 kHz to21 GHz with internal mixer, to220 GHz with external mixers. Op-tion 08 deletes coverage above21 GHz (calibrated mixers to60 GHz available from Tektronix).Frequency Accuracy — ±0.2% or5 MHz, whichever is greater, +20%of span/div.Frequency Readout Resolution— Within 1 MHz.Frequency Span per Division —10 kHz to 200 MHz plus zero andfull band max span, down to 500 Hzwith Option 03 in 1-2-5sequence.Frequency Span Accuracy —±5% of span/div, measured overcenter eight divisions.Resolution Bandwidth @ 6 dBPoints — 1 MHz to 1 kHz (100 Hzfor Option 03) in decade stepswithin ±20%, manually or auto-matically selected.Resolution Shape Factor(60/6 dB) — 7.5; maximum.

Spurious ResponsesResidual (no input signal) —-100 dBm or less referenced toinput mixer for fundamentalconversion.Harmonics — At least -60 dBc forfull screen signal in the Min Distor-tion mode to 21 GHz. At least -100dBc for preselected Option 01.1.7to 21 GHz.Intel-modulation — 3rd orderproducts at least -70 dB downfrom two full screen signals withinany frequency span in the Min Dis-tortion mode. At least -100 dBdown for two signals spaced morethan 100 MHz apart from 1.7 to 21GHz for preselected Option 01.L.O. Emissions (referenced toinput mixer)— 10 dBmmaximum; -70 dBm maximum forOption 01.Stability(after 2 hour warm-up)Residual FM—1 kHz peak-to-peakfor 2 ms time duration, improves to(50 Hz) for 20 ms with phaselockOption 03.Long Term Drift: 200 kHz/hour un-phaselocked, 25 kHz/hour phase-locked for fundamental mixing.Noise Sidebands — At least75 dBc @ 30X resolution offset(70 dBc for 100 Hz resolution) forfundamental mixing.

Amplitude RelatedReference Level Range —-123 dBm to +40 dBm (+30 dBmmaximum safe input) for 10 dB/divand 2 dB/div log modes. 20 nV/divto 2 V/div (1 W maximum safe input)in the linear mode.Reference Level Steps —10 dB, 1dB, and 0.25 dB for relative level (A)measurements in log mode. 1-2-5sequence and 1 dB equivalent in-crements in LIN mode.Reference Level Accuracy —Amplitude change of 0.25 dB±0.05 dB, 1 dB ±0.2dB,10dB

±0.5 dB; to a maximum of ±1.4 dBfor 60 dB and ±2 dB for 90 dB ref-erence level change when gainchange and attenuation do notoffset each other.Display Dynamic Range — 80 dB@ 10 dB/div, 16 dB @ 2 dB/div and

8 divisions linear.Display Amplitude Accuracy —±1 dB/10 dB to maximum of±2 dB/80 dB; ±0.4 dB/2 dB tomaximum of ±1 dB/16 dB; ±5% offull screen in LIN mode.*Resolution Bandwidth GainVariation— ±0 5dB

SENSITIVITY AND FREQUENCY RESPONSEAverage Noise Levelfor 1 kHz Resolution

Frequency Range

50kHz-1.8GHz'50kHz-4.2GHz'1.7-5. 5 GHz3.0-7.1 GHz5.4-18GHZ

15-21 GHz100MHz-18GHz"'

MixingNumber (n)

11113

3

NoPreselection

-115dBm-115dBm-115 dBm-115dBm-100 dBm

-95 dBm

With Tektronix optional high per1

18-26 GHz26-40 GHz40-60 GHz

61010

-100dBm-95 dBm-95 dBm

PreselectedOption 01

-110dBm-110dBm-110dBm-110dBm-95 dBm(12GHz)-90 dBm(18 GHz)-85 dBm

formance wavei

Frequency ResponseWith 10dB Attenuation

NoPreselection

±2,5dB±1.5dB±1.5dB±2.5dB

±3.5dB±3.5dB

guide mixers

±3dB±3dB±3dB

PreselectedOption 01

±1.5dB

±2.5dB±2.5dB±3.5dB

±5.0dB*"±4 5dB

"Low frequency end performance does not include effects due to zero Hz feedthrough."Flatness and accuracy specifications do not apply to the 30, 40, 50, and 60dBr/

attenuator positions between 19 and 20 GHz.** Includes frequency band switching error of 1 dB maximum.

10

Input CharacteristicsInternal Mixer — Type N femaleconnector, VSWR 1.45 to 18 GHz,and 3.5 to 21 GHz, with 10 dB ormore attenuation.Optimum Level forLinear Operation —-30 dBm referenced to mixer.1 dB Compression Point —-28 dBm from 1.7 to 2 GHz for Op-tion 01; otherwise -10 dBm.Maximum Safe Input Level —+13 dBm without Option 01,+30 dBm (1 W) with Option 01,zero rf attenuation.Attenuator Power Limit —+30 dBm (1 W) continuous, 75 Wpeak for 1 /us or less pulse widthand 0.001 maximum duty factor.

Output CharacteristicsCalibrator——20 dBm ±0.3 dB,100 MHz ±0.01%.1st L.O.—+7.5 dBm @ 50ftnominal.2nd L.O.——16 dBm @ 50ftnominal.Vertical Out—0.5 V ±5%/div, 1 kftnominal.Horizontal Out—0.5 V ± 10%/div, 1kft nominal.

Pen Lift —TTL, 5 V nominal.IF Out— -15 dBm nominal for fullscreen, -30 dBm display; 10 MHz,50ft.GPIB Control — IEEE 488 input/output control for 492 P

MiscellaneousSweep Time — 20 /xs to 5 s/div(10 s/div in auto) in 1-2-5 sequence.Crt Readout — Reference level,center frequency, frequency range,vertical display mode, frequencyspan/div, resolution bandwidth, andrf attenuation.Crt — 8 x 1 0 cm, P31 Phosphor.Power — 90 to 132 VAC, 180 to250 VAC, 48 to 440 Hz, 210 W maxwith all options.Environmental Characteristics —Per MIL-T-28800B type III, class 3,style C.Configuration—Portable, 20 kg(44 Ib) (all options), 17.5 x 32.7 x49.9 cm (6.9 x 12.9 x 19.7 in) withouthandle or cover.

"Flatness and accuracy specifications donot apply to the 30, 40, 50, and 60 dBrfattenuator positions between 19 and20 GHz.

Interpretingthe specifications

Low-End Frequency Performance.Frequency Drift.

Low-End FrequencyPerformance.Typical low-end frequencyperformance for the 492 isshown opposite in figure 1.Unlike many spectrumanalyzers with microwavemeasurement capability, the492 is specified for mea-surements down to 50 kHz.Resolution filter shape,phase noise sideband per-formance, input mixer cou-pling, and zero hertz localoscillator feedthrough canall contribute to limitinglow-end frequency per-formance.The 492 low-end frequencyspecification is 50 kHz. Thisis based on the fact that, fora basic 492, 50 kHz corre-sponds to center screen atthe narrowest available fre-quency span of 10 kHz/div.By comparison, aphaselocked 492 (with Op-tion 03), set at 100 Hz reso-lution; has a center fre-quency capability of 2.5 kHz(500 Hz/div).

Performance below 50 kHz isaffected by local oscillatorphase noise, input couplingand the zero hertz feed-through. Practical per-formance is limited toapproximately 5 kHz.

Note that, at 50 kHz, thenoise level is degraded toapproximately -90dBmfora 1 kHz resolution bandwidthdue to noise sidebandsaround the zero Hz feed-through.The zero Hz signal also lim-its the ability to set a smallsignal (e.g., -80 dBm) to fullscreen in 2 dB/div. Theseeffects are not significant atfrequencies above 1 MHz,and they can be circum-vented by using the Aamplitude mode.Frequency Drift.The relationship betweenlong-term, medium-term,and short-term frequencydrift for the 492 is illustratedin figure 2.Spectrum analyzer fre-quency drift is primarilycaused by changes in tem-perature and manifests itselfas a shift in signal displayfrequency even though inputsignal frequency remainsconstant. The apparentchange in frequency de-pends on several factors,including instrument tem-perature at turn-on, en-vironmental temperature,time since turn-on, whetheror not the 492 is phase-locked, the mixing harmonicnumber, and the period oftime over which the meas-urement is made.

-40

-60

o•o-80

-100

-120

1001 10Frequency (kHz)

Typicaf low end frequency performance for the 492 with Option 01(see text for explanation.)Figure 1

1000

/

turrwarr

/

-on-i-up—— 1

^

+*

/v JVW;VV-

>s

ta-^-

^vshc

resi

••nedk>rm c

rtterdual

m s

rift

m-M

^^

Dngt

S

3rm czer<

\

rift) drift

^v

line

*•— .

TimeRepresentative drift characteristics of modern spectrum analyzers.Figure 2

11

Interpreting the specifications

10,000

1,000

100Q

uc

10

1 1

nul; live drift

Ion 3 teim d r rr inut

specified two-hour warm-upperiod.Total cumulative drift afterthe two-hour warm-up isabout 5 MHz. At this point,the 492 has reached thelong-term drift specificationof 200 kHz/hr. The instru-ment should be recalibratedafter warm-up to maintainaccuracy.Frequency Drift DuringWarm-Up fora Phaselocked492 (Option 03).Adding phaselock (Option03) to a 492 helps minimizedrift. The first local oscillatoris stabilized (automatic at 50kHz/div at fundamentalconversion unless manuallyoverridden), leaving only

20 40 100 120 14060 80Time (Minutes)

Typical long term turn-on drift characteristics for an unphase-locked 492 starting at room temperature (fundamental mixing.Multiply by mixing N number for higher mixing products).Figure 3

Frequency Drift DuringSpecified Warm-Up Time.Because of the thermal na-ture of frequency drift, the492's behavior depends to agreat extent on externaltemperature conditions asthey affect the internal tem-perature of the instrument. A492 that has been out in thecold before warm-up maydrift more than one that hasbeen in the laboratory.Frequency Drift DuringWarm-Up For AnUnphaselocked 492.Turn-on drift as a function oftime is caused by environ-

12

mental changes. Becausethe 492 is designed to oper-ate in a wide variety of envi-ronments, drift is a more im-portant consideration for the492 than for a spectrumanalyzer designed for labuse only.For a typical unphaselocked492 starting out at roomtemperature, frequency driftduring the first half hour ofwarm-up is about 4 MHz, asshown in figure 3.The cumulative drift speci-fications shown in figure 3represent a slope of severalhundred kHz/min at turn-on,down to a few kHz after the

drift caused by the secondlocal oscillator. The secondoscillator is not affected byhigher mixing product mul-tiplication, and so drift is in-dependent of input fre-quency.Furthermore, 492 phaselockstabilization offers theequivalent of infinite hold-inrange, so that the first localoscillator will not break lockas it drifts. When phase errorvoltage reaches a prede-termined maximum, the tunevoltage is reset to maintainlock.A phaselocked 492 (Option03) starting at room temper-ature changes frequency byno more than 500 kHz in the

1,000

ulat ve c rift

Icngt:rrr nutf:

drift

40 100 120 14060 80Time (Minutes)

Typical long term turn-on drift characteristics for a phaselocked492 (with Option 03) starting at room temperature.Figure 4

Resolution Bandwidth.Harmonics and Intermodulation.

-60+-H-

Figure 5

first two hours. After thetwo-hour warm-up, the in-strument drifts a maximumof 25 kHz/hr — a specifica-tion that is almost ten timesbetter than without phase-lock. These specificationsrepresent an approximatedrift of 10 kHz/min at turn-onand 400 Hz/min after twohours, as shown in figure 4.Medium-Term Drift. Aphaselocked 492 (with Op-tion 03) exhibits excellentmedium-term drift at 100Hz/sec. An unphaselocked492 will exhibit medium-termdrift of about 2 kHz/sec.Medium-term drift is randomback and forth movement ofthe displayed signal afterthe instrument has warmedup.Incidental FM (Short-TermDrift), A phaselocked 492exhibits 50 Hz incidental fm,and a basic 492 exhibits1 kHz peak-to-peak. Inci-

dental fm (caused byshort-term drift) takes placein a very short time — oftenin milliseconds, at the mostin seconds — and it must bemeasured in a very shorttime as well.Resolution Bandwidth.492 resolution bandwidthsare specified at the 6 dBdown points. This specifica-tion represents the spacingof two equal amplitude sig-nals that can be well re-solved, as illustrated infigure 5.Depending on the applica-tion, other bandwidths maybe of interest: for example,3 dB, random noise, andimpulse bandwidths. Formost measurements, 492random noise and impulsebandwidths are approxi-mately equal to the 6 dBbandwidth, and the 3 dBbandwidth is approximately0.75 of the 6 dB bandwidth.Typical approximations aregiven in table 1.

Specified 6 dBResolutionBandwidth

±20%

100 Hz1 kHz10kHz100kHz1 MHz

Typical3dB

Bandwidth

75 Hz750 Hz7.5kHz75kHz750 kHz

TypicalImpulse

Bandwidth

100 Hz1 kHz9.5kHz100kHz800kHz"-

TypicalRandom

NoiseBandwidth

100 Hz1 kHz9.5kHz100kHz1 MHz*

*The pulse stretcher must be activated to achieve full impulse bandwidth at 1 MHz resolution setting.Table 1.

Harmonics andIntermodulation.The 492 specifications forharmonics and intermodula-tion are based on a-30 dBm rf signal level atthe first mixer. The followingworst-case specificationsrelate to the level referencedto the rf signal (in dBc):Harmonic Products —-60dBcThird-Order Intermodu-lation — -70dBcThe distortion-tree dynamicrange for any input level canbe computed from the inter-cept point equation:I = _A_ + S, where

N-1I = Intercept point in dBm.A = Distortion level relativeto input carriers in dB.N = Distortion order numbers.S = Input signal level to themixer in dBm*For second-harmonic distortion,I = 60_ + (-30) = +30 dBm.

2-1For third-order distortion,I = 70_ + (-30) = +5 dBm.

3-1

Optimal distortion-freedynamic range occurs whenthe distortion productsequal the sensitivity noiselevel (n) in dBm.For the 492 with preselectorat 100 Hz resolution, n =-118 dBm for fundamentalconversion. Thus,S0 = (N-1) I +n

N= (2)5 +(-118) = -36 dBm,

and

N= (2) (123) =82 dBc.

3Best distortion-free dynamicrange for closely spacedsignals is 82 dB. Inter-modulation dynamic rangereaches 100 dB for signalspacings greater than100 MHz for the 1.7 to21 GHz frequency range.

"Input level to the mixer is spectrum analyzerinput level lessrf attenuator level. Thus, a+10 dBm input with 30 dB of rf attenuation isa mixer input level of +10-30 = -20 dBm.

13

Interpreting the specifications

m•o

-30-40-50-60-70

pn

-90

-110-120

1 M

10k

100

coa

HzE

Hzd

Hzb

x ir

W

W

W

put

r

r_r^

\

i J-

J^k

— 1~

vavfuidipttt

i

; --»-

resolution bandwidth filterthat exhibits 1.1 MHzbandwidth at 80 dB down.Phase noise sidebands arethe limiting factor closer in.Figure 8 shows the samesignal with a 1 kHz resolutionbandwidth filter.

Note that the phase noisesideband pedestal breaksout at 70 dB down, droppingto 75 dB down at 20 kHzoffset from the carrier. Thisallows easy observation ofclose-in sidebands 10 kHzout and 70 dB down.

1 10Input Frequency (GHz)

Sensitivity showing average noise level fora preselected492 (Option 01).Figure 6

100

Sensitivity.Sensitivity for a preselected492 (Option 01) is shown infigure 6.Note that, although a non-preselected 492 has 5 dBlower input loss, and there-fore 5 dB better sensitivity,the spurious-free dynamicrange of the preselected in-strument is superior.Sensitivity is specified interms of the smallest ob-servable signal, and istherefore determined byspectrum analyzer internalnoise level. Noise level de-pends on resolution band-width and local oscillatormixing multiplicationnumber. (Refer to figure 6.)

Dynamic Range.On-screen dynamic range ofthe 492 is 80 dB at a verticaldisplay scale factor of10dB/div.Intermodulation distortiondynamic range for signalsspaced closer than 100 MHzis consistent with on-screendynamic range at 80 dB.For small signals or modula-tion components next to alarge carrier, the dynamicrange can be considerablygreater. Limiting factors areresolution bandwidth filtershape, phase noise side-band characteristics, andinput overload capability.For resolution bandwidthswider than 10 kHz, filtershape is the limiting factor.Figure 7 shows a 100 kHz

100

76

50

75

50

25

II

1 __

.

;

:

t

i l l .

MHz

, ,V, , , , , ..L..I._I •

80 d

-...<--! .1 1

Be

i

IEF

-10

-20

-30

-40

-20

-30

-<0

^50

-60

-70

i i

IDG

dB

Figure 7

14

Sensitivity.Dynamic Range.

Amplitude Accuracy.Reference Level.

Figure 8

Figure 9 shows typical filtershape, phase noise side-bands, and sensitivity fac-tors for fundamental mixingon a preselected 492 (Op-tion 01).

Amplitude Accuracy.The amplitude reference forthe 492 is a -20dBm,100 MHz calibrator. Theamplitude accuracy of thissignal is ±0.3dB. Factorsaffecting measurement ac-curacy depend on input sig-nal frequency and amplitudeas follows.

Frequency response perband.The frequency response forthe first band is referencedto the 100 MHz calibrationpoint.A band-to-band referenceerror of 1 dB must be addedto the per-band frequencyresponse specificationswhen the instrument is oper-ating outside the first band.Amplitude measurementerror resulting from fre-quency response dependson the frequency of the in-coming signal.* Approxi-mately ±1 dB is contributedby the preselector (Option01), and the remainder iscontributed by other inputcircuits.

-10-20-30-40-50-60-70-80-90

-100-110-120-130-140 1 1,00010 100

Offset Frequency (kHz)Typical filter shape, phase noise sidebands, and sensitivity factorsfor fundamental mixing on a preselected 492 (Option 01).Figure 9

10,000

"Flatness and accuracy specifications dcnot apply to the 30, 40, 50, and 60 dB rfattenuator positions between 19 and20 GHz.

A nonpreselected 492 hasalmost 1 dB better amplitudeaccuracy.Amplitude Display.An amplitude display errorof0.4dB/2dB, 1 dB/10dB,and 2 dB/80dB occurswhen signal display ampli-tude is not at the full screenreference level.Reference Level.Gain/attenuation errors areintroduced when the refer-ence level is changed fromthe -20 dBm calibratorlevel.Absolute reference level indBm can be changed in1 dB and 10 dB steps.Reference level change er-rors are ±0.2dB/1 dB,±0.5 dB/10 dB accumulat-ing to ±1.4dB/60dB, and±2 dB/90dB. This erroranalysis is worst case, pro-

viding gain and attenuationare not switched in simul-taneously. This is normallyprevented by the 492's au-tomatic reference levelmode.A -20 dBm calibration levelshould preclude having toswitch gain and attenuationtogether.A10 dB minimum rf inputattenuation setting duringcalibration allows for smallsignals that require someattenuation to provide goodimpedance match. The useralso has the option of cali-brating at -20 dB and zerodB attenuation by activatingthe MIN NOISE control.

15

Interpretingthe specifications

Relative Reference Level Steps.

0

„ 2Qut 4to•a+l 6

8

10

=1-80

-2n

ff

4

dBm

rlBm

sign;

sinn

1--4-i

ji

Relative Reference LevelSteps.The 0.25 dB steps are ena-bled in the 2 dB/div verticalmode when "Fine" steps areselected. These steps areused for accurate relativeamplitude difference mea-surements. The total mea-surement range is 50 dB,with an accuracy of0.05 dB/0.25dB,0.4dB/2dB,1 dB/10dB,and 2 dB/50 dB.

Typical accuracy limits ineach band for a preselected492 are summarized in table2. Worst case accuracylimits including band-to-band error of 1 dB are illus-trated in figures 10 and 11.

0 2 4 6 8 10 12 14 16 18 20 22 24 26Measurement Frequency (GHz)

Cumulative maximum absolute amplitude measurement error as afunction of signal amplitude and frequency for a preselected 492(Option 01) assuming calibration using the internal -20 dBm 100 MHzreference.Figure 10

OdB'ref level ciang

FrequencyResponse

Frequency Range ±dB Max.

50kHz-1.8GHz1.7GHz-5.5GHz3.0GHz-7.1 GHz5.4GHz-18.0GHz15.0 GHz-21.0 GHz18.0GHz-26.5 GHz**26.5GHz-40.0GHz40.0 GHz-60.0 GHz

1.52.52.53.55.0333

IF Gain*Variation±dB Max.

0.50.50.50.50.50.50.50.5

CalibratorOutput

±dBMax.

0.30.30.30.30.30.30.30.3

Total±dB Max.

2.33.33.34.35.83.83.83.8

"10 dB steps over a 70 dB range"Using optional accessory high performance mixers

Achievable amplitude accuracy for a preselected 492 is shown above.Table 2.

10

50 d 3 ref evel ;han je

2 4 6 8 10 12 14 16 18 20 22 24 26Frequency Difference (GHz)

Cumulative maximum error in measurement of relative amplitude oftwo signals as a function of reference level change and frequencyseparation, fora pre-selected 492 (Option 01).Figure 11

16

Option Configurations

Two basic models of spec-trum analyzer are available,the 492 Spectrum Analyzerand the 492P ProgrammableSpectrum Analyzer. You canorder either model with anycombination of the availableperformance options andoptional accessories to con-figure the instrument for yourrequirements.The 492P is fully compatiblewith the IEEE-488 interfacebus (GPIB) and can be op-erated through any control-ler capable of interfacingthrough the bus, especiallythe Tektronix 4050 Seriessystems. All important frontpanel controls functiondigitally and can be oper-ated by the controller. Thus,the 492P not only transmitsdata to the controller, butmay be programmed by thatcontroller. A remote/localswitch on the 492P frontpanel provides for local,manual control of theanalyzer, overriding pro-gram control.The front panel may also belocked out by the controllerfor testing situations inwhich the possibility of localcontrol might invalidatemeasurement results.For general use spectrumanalysis, optimum perform-ance may be obtained withthe inclusion of Options 01,02, and 03.

Option 01 — InternalPreselection.With this option, internallygenerated image and har-monic mixing spurious re-sponses are effectivelyeliminated. This results in adisplay that is much easierto interpret. In the frequencyrange of 50 kHz to 1.7 GHz,a low-pass filter is used tolimit spurious responses. Inthe range of 1.7 GHz to21 GHz, a tracking YIG pre-selector is used. Internalcalibrated preselection re-duces the requirement toexamine each signal to ver-ify authenticity.Measurement capability isenhanced with Option 01 byan increase in dynamicrange from 80 dB in thebasic analyzer to 100 dB (forsignals separated by 100MHz). This is because theautomatic tracking pre-selector rejects signals out-side its bandwidth by 70 dBor more.Option 01 also includesa limiterto provide +30dBm input protection to thefirst mixer up to 1.7 GHz.Above 1.7 GHz the inputmixer is protected by thepreselector.

Option 02 —DigitalStorage.Spectra may be digitized with500 point resolution and heldin one of two memories, A orB—or in a 1000 point mem-ory created by combining Aand B. Once in memoryspectra may be displayedwith a bright flicker free trace,making prolonged viewing orphotography easy—espe-cially for single sweep or slowsweep speeds. Digital stor-age also adds several internaldata processing features:Digital averaging — Data ateach frequency point inmemory is summed and di-vided by the number ofsamples at that frequency.Peak Detection — Data ateach frequency point iscontinuously updated withpeak-detected values.Digital cursor — An adjust-able cursor allows theoperator to obtain a com-bined peak/average display— data above the cursor isshown peak-detected, databelow the cursor is aver-aged.With MAX HOLD mode, thehighest amplitude attained ateach of the 1000 points dur-

ing successive sweeps isstored and displayed. Thismode is useful for measuringpeak-to-peak drift over a timeinterval or in making sweptresponse measurements offilters without a trackingsource.With SAVE A mode, one sig-nal is stored in the A memoryfor later examination. This in-formation is not updated andis useful in instances of latercomparison with other signalinformation. In the B MINUSSAVE A mode, the A signal isstored and not updated, thenarithmetically subtracted fromthe B signal, which may becontinually updated. Thismode is most useful for com-paring signals such as in pro-duction test comparison of asignal with a standard, or forcalibrating frequency re-sponse uncertainty out of ameasurement.

17

Ordering Information

With the AVERAGE mode,the display is divided by ahorizontal cursor. Above themoveable cursor, signalsare peak detected and dis-played. Below the cursor,signals are averaged. Av-eraging is useful for appli-cations in which signalsmust be analyzed in thepresence of high noiselevels. The trace smoothingthat occurs through av-eraging simplifies theprocess.Digital averaging and videofiltering may be used jointlyor independently dependingon the nature of the signal.

In addition, with digital stor-age, slowly swept signals areeasy to observe and photo-graph, and do not requireintensity or other display re-adjustments.Option 03 — FrequencyStabilization/100 HzResolution.With this option, phase-locked local oscillatorstabilization provides ex-ceptional display stabilityand low noise sidebands,

and results in less frequencydrift and less residual fm.Thus, the 492 user can ob-serve and measure charac-teristics of lower modulationfrequencies. As part of Op-tion 03, improved resolution(100 Hz) and narrow span of500 Hz/Div. provide in-creased measurementcapability for close insideband analysis. Thespecial purity of cleanoscillators may thus bemeasured directly at micro-wave frequencies. The 492retains its one knob centerfrequency control with Con-stant Tuning Rate(CTR)even with phaselock.Option 03 is recommendedwhen the 492 will be used atspans less than 50 kHz perdivision, and is required forspans of less than 10 kHzper division. Phaselock oc-curs automatically and is afunction of the setting of thespan/div control. For con-venience in operating theanalyzer in fixed tuned re-ceiver (zero span) mode,phaselock may be deacti-vated by a front panelcontrol.Option 08 — DeleteExternal Mixer Capability.Option 08 deletes externalmixer capability for extend-ing frequency range above21 GHz.

18

Option 20 — General Pur-pose 12.5 GHz to 40 GHzWaveguide Mixer Set.This option extends the op-erational upper frequency ofthe 492 or 492P to 40 GHz.The actual waveguide rangeis 12.5 to 40 GHz. This op-tion package, designed toprovide economical use ofthe analyzer at frequenciesabove 21 GHz, consists ofthree waveguide mixers anda connecting coaxial cable.Option 21 — High Per-formance 18 GHz to40 GHz WaveguideMixer Set.This option consists of twowaveguide mixers and acoaxial cable, and extendsthe operational upper fre-quency of the 492 or 492P to40 GHz. The actual wave-guide range is 18 to 40 GHz,and the mixers are designedso that, in operation with theanalyzer, the system is cali-brated in amplitude, flat-ness, and sensitivity.Option 22 — High Per-formance 18 GHz to60 GHz WaveguideMixer Set.This option consists of threewaveguide mixers and aconnecting coaxial cable,and extends the operationalupper frequency of the 492or 492P to 60 GHz. The ac-tual waveguide range is 18to 60 GHz, and the mixersare designed so that, in op-eration with the analyzer, thesystem is calibrated inamplitude, flatness, andsensitivity.

Combined options.The basic 492 SpectrumAnalyzer or the basic 492PProgrammable SpectrumAnalyzer may be ordered withmany combinations of op-tions and optional acces-sories. The prices are additive(except for one delete option,Option 08, which deletes ex-ternal mixer capability). Notethat the standard accessoriesare listed only once (with thebasic 492), but that one set isincluded with either spectrumanalyzer.Also listed with the 492P arethe companion 4052 GraphicComputing System Controller,4631 Hard Copy Unit, 4662Interactive Digital Plotter and4924 Digital Cartridge TapeDrive.492 Spectrum Analyzer $18,500.00

Including the following listed stand-ard accessories: Diplexer Assem-bly (015-0385-00); 50 fi CoaxialCable, N to N Connectors, 6 foot (1)(012-0114-00); 50 n Coaxial Cable,BNC to BNC Connectors', 18 inch(1) (012-0076-00); Adapter, N Maleto BNC Female (1) (103-0045-00);CRT Mesh Filter (1) (378-0726-01);Fuse 2 A, Fast Blow (1) (159-0021-00); Fuse 4 A Fast Blow (2)(159-0017-00); Power Cord, 115-V(1) (161-0118-00); Cord Clamp (1)(343-0170-00); CRT Light Filter,Blue (1) (378-0115-00); CRT LightFilter, Amber (1) (378-0115-00);CRT Light Filter, Gray (1) (378-0115-02); CRT Visor (1) (016-0653-00); Operator's Manual (1);Operator's Handbook (1);Service Manual, Volume 1 (1); andService Manual, Volume 2 (2).

492P Programmable SpectrumAnalyzer . . . . . . . . . . . . . $22,500.00Including Programmers Manualand the listed standard 492accessories.

4052 Graphic Computing SystemController . . . . . . . . . . . . $10,950.004631 Hard Copy Unit . . $ 4,850.004662 Interactive DigitalPlotter . . . . . . . . . . . . . . . $ 4,495.004924 Digital Cartridge TapeDrive . . . . . . . . . . . . . . . . $ 2,695.00

Option OrderingInformation.Option 01—InternalPreselection . . . . . . . Add $3,800.00Provides calibrated preselectedfiltering of input to first mixer foreach frequency band.Option 02—DigitalStorage Add $1,700.00Provides multiple memory displaystorage with SAVE A, MAX HOLD, BMINUS SAVE A, display average,and storage bypass.Option 03—FrequencyStabilization/100 HzResolution . . . . . . . . Add $3,250.00Provides first local oscillator stabili-zation by phaselocking the oscil-lator to an internal reference. Alsoprovides 100 Hz resolution.Option 08—Delete External MixerCapability . . . . Subtract $1,250.00Deletes internal switching frontpanel connector and external di-plexer to connect and use externalwaveguide mixers.Option 20—General-Purpose 12.5to 40 GHz Waveguide MixerSet Add $520.00Includes three mixers (12.4 to 18GHz, 18 to 26.5 GHz, and 26.5 to40 GHz) and attaching hardware toextend the 492 upper frequency.Option 21—High Performance 18to 40 GHz Waveguide MixerSet Add 1,970.00Includes two mixers (18 to 26.5 GHzand 26.5 to 40 GHz) and attachinghardware to extend the 492 upperfrequency.Option 22—High Performance 18to 60 GHz Waveguide MixerSet Add $3,220.00Includes three mixers (18 to 26.5GHz, 26.5 to GHz, and 40 to 60GHz) and attaching hardware toextend the 492 upper frequency.

Optional AccessoriesThe following listed accessories areoptional with all models and config-urations of the 492 system, and maybe ordered in any combination.General Purpose 12.5 to 40 GHzWaveguide Set(016-0656-00) . . . . . . . . . $ 550.0012.4 to 18 GHz Mixer(119-0097-00) . . . . . . . . . 150.0018.0 to 26.5 GHz Mixer(119-0098-00) . . . . . . . . . 190.0026.5 to 40 GHz Mixer(119-0099-00) . . . . . . . . . 220.00Cable (012-0748-00) . . . 20.00Case (004-1651-00) . . . . 35.00High Performance 18 to 40 GHzWaveguide Mixer Set(016-0662-00) . . . . . . . . . $2,005.0018 to 26.5 GHz Mixer(016-0631-01) . . . . . . . . . 975.0026.5 to 40 GHz Mixer(016-0632-01) . . . . . . . . . 975.00Cable (012-0649-00) . . . 25.00Case (004-1651-00) . . . . 35.00High Performance 18 to 60 GHzWaveguide Mixer Set(016-0657-00) . . . . . . . . . $3,255.0018 to 26.5 GHz Mixer(016-0631-00) . . . . . . . . . 925.0026.5 to 40 GHz Mixer(016-0632-00) . . . . . . . . . 925.0040 to 60 GHz Mixer(016-0634-01) . . . . . . . . . 1,250.00Cable (012-0649-00) . . . 25.00Case (004-1651-00) . . . . 35.00Microwave Comb Generator(067-0885-00) . . . . . . . . . $1,800.00C-5C Camera . . . . . . . . . 425.00TV Trigger Synchronizer(015-0261-00) . . . . . . . . . 360.00Hard Case (transit)(016-0658-00) . . . . . . . . . 495.00Soft Case (016-0659-00) 125.00Note: The 492 Spectrum Analyzer

system is compatible with allTektronix C50 Seriescameras.

19

For the address of your nearestTektronix Field Office, contact:

U.S.A., Asia, Australia, Central & SouthAmerica, JapanTektronix, IncP.O. Box 1700Beaverton, OR 97075Phone: 800/547-1512Oregon only 800/644-9051503/644-0161Telex: 910-467-8708Cable: TEKTRONIXEurope, Africa,Middle EastTektronix International, Inc.European Marketing CentrePostbox8271180 AV AmstelveenThe NetherlandsTelex: 18312CanadaTektronix Canada Inc.P.O. Box 6500Barrie, Ontario L4M 4V3Phone: 705/737-2700Tektronix Distributors to serve youaround the world:Argentina, Australia, Austria, Belgium,Bolivia, Brazil, Canada, Chile, Colombia,Costa Rica, Denmark, East Africa, Ecuador,Egypt, El Salvador, Federal Republic ofGermany, Finland, France, Greece, HongKong, Iceland, India, Indonesia, Iraq, Israel,Italy, Ivory Coast, Japan, Jordan, Korea,Kuwait, Lebanon, Malaysia, Mexico,Morocco, The Netherlands, New Zealand,Norway, Pakistan, Panama, Peru,Philippines, Portugal, Republic of SouthAfrica, Saudi Arabia, Singapore, Spain,Sri Lanka, Sudan, Surinam, Sweden,Switzerland, Syria, Taiwan, Thailand,Turkey, Tunisia, United Kingdom, Uruguay,Venezuela, Zambia.

Copyright © 1980, Tektronix, Inc. All rightsreserved. Printed in U.S.A. Tektronix prod-ucts are covered by U.S. and foreign pa-tents, issued and pending. Information inthis publication supersedes that in all pre-viously published material. Specificationand price change privi leges reserved.TEKTRONIX, TEK, SCOPE-MOBILE, and&jl are registered trademarks of Tektronix,Inc. TELEQUIPMENT is a registeredtrademark of Tektronix U.K. Limited. Forfurther information, contact: Tektronix, Inc.,P.O. Box 500, Beaver ton, OR 97077.Phone: 503-644-0161; TWX 910-467-8708;Cable: Tektronix. Subsidiaries and distrib-utors worldwide.

Performanceworth the

___name

TektronixCOMMITTED TO EXCELLENCE

5/80