HP-202A-Manual-SNprefix-037 电路图.pdf

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1、HP Archive This vintage Hewlett Packard document was preserved and distributed by Pleasevisituson the web! Scanned by on-line curator: Tony Gerbic * For FREE Distribution Only * RadioFans.CN 收音机爱 好者资料库 HEWLETT-PACKARDCOMPANY 202A LOWFREQUENCY FUNCTION GENERATOR N o N RadioFans.CN 收音机爱 好者资料库 000113 O

2、PERATINGANDSERVICEMANUAL MODEL202A SERIALSPREFIXED:037- LOWFREQUENCY FUNCTIONGENERATOR CopyrightHEWLETT-PACKARDCOMPANY1959 1501 PAGE Mll.L ROAD,PALOALTO, CALIFORNIA.U.S.A. Printed:MAR1962 RadioFans.CN 收音机爱 好者资料库 TableofContents Listoflllustrations TABLEOFCONTENTS SectionPageSectionPage IGENERAL INFO

3、RMATION1-1 IV MAINTENANCE (contd) 1-1.General. . . . . .1-14-3.FunctionGenerator(bi-stablecir- cuitandintegrator). .4-2 4-4.SineSynthesizerandFunction IIOPERATING INSTRUCTIONS.2-1 Selector.4-2 2-1.Inspection2-1 4-5.OutputAmplifier4-3 . . . 4-6.SyncOut.4-3 2-2.ControlsandTerminals.2-1 . . 2-3.230-Vol

4、tOperation.2-1 4-7.TubeReplacement. .4-3 . 4-8.TubeReplacementChart4-4 2-4.Operation. .2-1 4-9.PowerSupplyRegulatorAdjustment.4-4 2-5.Single-EndedOutput2-2 2-6.BalancedOutput.2-2 4-10.TheoryofDCBalanceandDist DistortionAdjustments4-5 2-7.Sync.Out. . 2-2 4-11.DCBalanceandDistortion. Adjustments.,4-5

5、4-12.AdjustSquarewaveAmplitude4-8 IIIPRINCIPLESOF OPERATION.3-14-13.FrequencyRatioandCalibration 3-1.General3-1Procedure.4-8 3-2.Bi-StableCircuit.3-24-14.Replacementof R58Potentiometer4-8 3-3.LinearIntegrator.3-34-15.PerformanceCheck.4-8 3-4.SineSynthesizerandFunction4-16.Output Voltage andWaveform

6、SelectorSwitch.3-4Check4-8 3-5.OutputSystem.3-64-17.SyncPulseCheck4-10 3-6.SyncPulseOutput.3-74-18.Sine WaveDistortionCheck.4-10 3-7.PowerSupply .3-84-19.DialAccuracyCheck4-10 IV. MAINTENANCE. 4-1.General 4-2.PowerSupply. 4-1 4-1 4-1 VTABLEOFREPLACEABLEPARTS. 5-1.TableofReplaceableParts 5-1 5-2 4-6

7、4-13 4-14 4-15 PageFigure 4-1.MinimumDistortionandFrequency AdjustmentInstrumentation. . . 4-2.EffectofTriangleMaladjustmenton DistortionandFrequency. . . . . .4-7 4-3.PatternsShowingtheAdjustmentsof R49, R51, R60andR119toObtainMinimum DistortionandCorrectFrequency. .4-9 4-4.Output VoltageandSyncPul

8、seTestSetup.4-10 4-5.Sine WaveDistortionTestSetup . . . .4-10 4-6.DialAccuracyTestSetup4-10 4-7.Model 202A Top ViewCoverRemoved.4-12 4-8.Model 202ABottomView BottomPlateRemoved. . . . . . 4-9.FunctionGeneratorandAmplifier. 4-10.PowerSupply. LISTOFILLUSTRATIONS PageFigure 1-1.Model 202A LowFrequencyF

9、unction Generator. . . . . . . . . . .1-0 2-1.Single-EndedOutputConnections2-2 2-2.BalancedOutputConnections2-2 3-1.Model202AFunctionGenerator.3-1 3-2.DetailsofBi-StableCircuitand SwitchingSystem. . . . . . .3-2 3-3.GeneralizedMillerorFeedback Integrator. . . . . . . . . .3-3 3-4.SimplifiedLinearInt

10、egrator . .3-4 3-5.SineSynthesizerandFunctionSelector.3-5 3-6.50,Waveforms.3-5 3-7.OutputAmplifierSystemofModel202A.3-6 3-8.Sync OutputCircuitof Model 202A3-7 3-9.Model 202APowerSupply3-7 00011-2 iii Sect.IPage0 00011-2 Figure1-1.Model202A.LowFrequencyFunctionGenerator Table1-1.Specifications FREQUE

11、NCYRANGE: 0.098to1200cpsinfivedecaderangeswith wideoverlapateachdialextreme DIAL ACCURACY: Within2%from1.2to12ondial;3% from.8to1.2 FREQUENCYSTABILITY: Within1%includingwarm-updriftandline voltagevariationsof 10% OUTPUTWAVEFORMS: Sinusoidal,square,andtriangular.Selectedby panelswitch MAXIMUMOUTPUTVO

12、LTAGE: Atleast30voltspeak-to-peakacrossratedload (4000ohms)forallthreewaveforms.(10.6 voltsrmsforsinewave) FREQUENCYRESPONSE: ConstantwithinO.2 dboverentirefrequency rangeatratedoutputandload INTERNALIMPEDANCE: Approximately40ohmsovertheentirerange SINE WAVE DISTORTION: Lessthan1%onallrangesexceptX1

13、00.Less than2%rmson X100. 00011-2Sect. IPage1 SECTIONI GENERALINFORMATION 1-1GENERAL TheModel 202A LowFrequencyFunctionGenerator isacompact,convenient,andversatilesourceof transient-freetestvoltagesbetween.008 and 1200 cyclespersecond.Itisusefulforanygeneral purposelowfrequencytestingapplicationandi

14、s particularlyvaluable in thetestingofservosystems, geophysical equipment,vibrationandstabilitychar- acteristicsofmechanicalsystems,electro-medical equipment,andfortheelectricalsimulationof mechanicalphenomena.Threetypes of outputwave- formareavailable;sine,squareandtriangular. Also, a sync output p

15、ulseisavailableforexternaluse. TheModel 202A LowFrequencyFunctionGenerator containsa typeofrelaxationoscillatorthatispar- ticularlyadvantageousforthegenerationofverylow frequencies.Bothatriangularandasquarewave voltage function of timeareinherent in theoscillating system.Also,asinewavefunctionisprod

16、uced bysynthesisfromthetriangularwave. OutputamplitudeanddistortionareVirtuallyin- dependentofthefrequencyofoperation.Thistype ofoscillatingsystemininherentlyaconstantam- plitudedevicesothatnoA.V.C.system,withas- sociated delay in stabilizationafterfrequency changes, isrequired Thefrequencyrangefrom

17、.008to1200cyclesper secondiscoveredin 5bands.Thefrequencydial islinear. Theoutputsystemisadirect-coupledamplifier systemdesignedforeithersingleendedorbalanced output.Ithasgoodstabilitywithrespecttodirect currentintheoutput andverylowhumlevel.Both the FUNCTIONselectroswitchandthe AMPLITUDE controlare

18、soarrangedthatthecharacteristicsof theamplifierareindependent oftheirposition.The internalimpedance of the outputamplifierisapprox- imately40ohms,andtheunitisratedtodeliver atleast30voltspeak-to-peakto a 4000ohmload. Anegativepeaksyncpulseof10voltsinto a 2500 ohmloadisalsoprOVided.Ithasadurationofle

19、ss than5microsecondsandoccursatthecrestofthe sinewaveandatcorrespondingpositionswiththe otherfunctions. Table1-1.Specifications(Contd) OUTPUT SYSTEM: Canbeoperatedeitherbalancedorsingle- ended.Outputsystemisdirect-coupled;dc levelof outputvoltageremainsstableoverlong periodsoftime. HUMLEVEL: Lesstha

20、nO.5%atratedoutput. SYNC PULSE 10voltspeaknegative,lessthan5microseconds duration.Syncpulseoccursatcrestofsine wave andwithcorrespondingpositionsonother waveforms. WEIGHT: CabinetMount:Net42lbs RackMount:Net 37Ibs POWER: 115or230volts10%,50to1000cps,150watt DIMENSIONS:CabinetMount:20-3/4in. wide, 12

21、-3/4in.high,14-5/8in.deep. RackMount: TOP J. 2-1INSPECTION Aftertheinstrumentisunpacked, theinstrument should becarefullyinspectedfordamagereceived intransit.Ifany shipping damageisfound, follow theprocedureoutlined in theClaimforDamage in Shipment pageatthebackof theinstructionbook. 2-2CONTROLSANDT

22、ERMINALS RANGE Thisswitchisused toselectthedesiredfrequency range to becoveredby the frequency dial. FUNCTION Thisswitchisusedtoselectanyoneof thethree typesof outputwaveform. FREQUENCY Thisdialiscalibrateddirectlyincyclespersecond fortheXlfrequencyrangeof theoscillator.The knobjustbelow thedialescu

23、tcheonisdirectlycon- nectedtothe frequency varying element.The lower knobisamechanicalvernierforfineadjustment ofthefrequency. AMPLITUDE Thiscontroladjuststhe amplitudeoftheoscillator voltage admittedtotheamplifierand,therefore,the outputofthe instrument.Thiscontroliscalibrated from0to100inarbitrary

24、units. POWER Thistoggleswitchcontrolsthepowersuppliedto theinstrumentfromthepowerline. FUSE The fuseholder, whichislocated on the panel,con- tainsthepowerlinefuse.RefertotheTableof ReplaceablePartsforthecorrectfuse rating. Sect. II Page 1 SECTIONII OPERATINGINSTRUCTIONS OUTPUT Thisgroupconsistsofthr

25、eeterminals.The one markedGisconnecteddirectlyto theinstrument chassis.The othertwoterminals,verticallyaligned, aretheOUTPUTterminals.Withrespectto the groundterminaleachoftheseoutputshasequal magnitude of signal, but theyare180 0 out of phase witheachother.Theinternalimpedance between thetwoOUTPUT

26、terminalsisapproximately40ohms. SYNCOUT The Sync Outterminalsaresingle-endedandhave aninternalimpedance of about2,000ohms. PowerCable Thethree-conductorpowercableissuppliedwith athree-prongplug.Thethirdprongisaround off-setpinwhichprovidesachassisground.An adaptermaybe obtained topermituse ofthisplu

27、g withtwo-conductorreceptacles. 2-3230-VOLTOPERATION Thisinstrumentisshippedfromthefactorywith thepowertransformerprimariesconnectedin parallelfor115voperation,unlessotherwisespec- ified on theorder.If230v operationisdesired,the primarieswillhaveto beconnectedinseriesas shown inTransformerDetailson

28、the Schematic wiringdiagramofthePowerSupply Section. 2-4OPERATION Thefollowingstep-by-stepprocedureshouldbe usedasa guide whenoperatingthisinstrument. 1)TurnthePOWERswitchtoON.Allowthirty secondsforoscillationstostart.Theinstrument willoperatenearlywithinspecificationsaftera fewminuteswarm-up.Itwill

29、be withinspecifi- cationsafter30minutes. Sect.IIPage 2 2)Set theRANGEand FREQUENCYcontrolsforthe desiredfrequency.Thefrequencydialscalemust bemultipliedby themultiplyingfactorindicatedby the RANGEswitchsettingtoobtaintheoscillator frequency.Example:4 (ondialscale)x .1(multi- plyingfactorindicatedby

30、RANGEswitchsetting) =.4cycles/sec. 3)Set the FUNCTIONswitchforthedesiredoutput waveform. 4)Connect the equipmentundertestto the OUTPUT terminals. 5)Adjustthe AMPLITUDEControlforthedesired outputvoltage.Becausethefrequencyresponse isratedO.2 db, the output amplitudemaybemea- suredatanyconvenientfrequ

31、encyandtheoutput levelwillbecorrect(withintheselimits)forany otherfrequency. NOTES mustbe connected to one of the OUTPUTterminals, and thestrappedpairwill then be the groundsideof the output. 2-6BALANCEDOUTPUT Connect the two OUTPUT bindingpoststo the eqUip- mentbeingsupplied.TheGbindingpostmay then

32、beconnectedtothechassisoftheequipment beingdriven.Undertheseconditionstheinternal impedanceof the Model 202AfromeitherOUTPUT terminalto groundis7900 ohms inserieswith a 1J.Lf capacitor(C29).A maximum de voltage of 400volts maybeappliedbetweeneitherOUTPUTterminal andtheGterminalwithoutdamagingthe1J.L

33、f capacitor(C29).The40ohmsinternalimpedance (resistive)will shunt the impedanceexistingbetween thetwosignalinputsofthesystembeingdriven. Undercircumstanceswheretheconnectionplaces the Model 202Ainserieswith apathcarryingcur- rent,distortionof the Model 202A output willoccur ifgreaterthan10rnapeakcur

34、rentiscausedto flow throughtheModel 202A outputsystem. Whensmalloutputvoltagesarerequireditmaybe desirabletouseanexternalattenuator.Thisis becausethehumandnoiseintheoutputisnearly constantwithoutputamplitude. Tominimizedistortionintheoutputwaveform, alwaysusethelowestRANGEwhentheoverlap oftheFREQUEN

35、CYdialpermitsachoice. OUTPUT G EQUIPMENT BEING SUPPLIED groundorno signalpoint RO 2-5SINGLE-ENDEDOUTPUT TheterminalmarkedGisisolatedfromtheactual OUTPUTtenninals.Forsingle-endedoperationG EQUIPMENT BEING SUPPLIED OUTPUT RO Figure2-lSingle-Ended Output Connections Figure2-2.BalancedOutput Connections

36、 2-7SYNC.OUT TheSYNC.OUTisanegativepulseoflessthan 5microsecondsdurationandatleast10voltspeak amplitude.Itoccursononeofthesineandtri- angularcrestsandattheriseorfallof thesquare- wave.noccursatthepositivecrestswithrespect tooneoftheOUTPUTterminalsandatthenega- tivecrestoftheother.Therefore,itcanbe c

37、hanged by1800withrespecttotheoutputsystembyre- versingconnectionstothetwoOUTPUTterminals whichareotherwisecompletelyinterchangeable. TheSYNC. OUTterminalmarkedGisdirectly connectedtothechassis. 00011-2Sect.mPage1 SECTIONIII PRINCIPLESOFOPERATION 3-1GENERAL Figure3-1 depicts thegeneralscheme of theMo

38、del 202A and indicates the waveforms produced.Thebi- stablecircuitconsistsofaflip-flopcircuitcapable ofproducingasquare-waveoutputatpointA,pro- videditistriggeredatthepropertime.Thisis done by including in thebi-stablecirCUit, a two-way comparatorcircuitwhichproducesthepropertrig- gersforthe flip-fl

39、opwheneverthe switc.hingsignal becomes equal toeithertheplusswitchingreference ortheminusSWitchingreference.Thetriangular switchingsignalreturnedtothebi-stablecircuit isthatseenbetween pointsBandD.The conversion ofsquarewavetotriangularwavetakesplacein theintegratorunitwhichiscarefullydesignedto pro

40、duceanaccurateintegraloftheappliedsquare wave.Thebi-stablecircuitandlinearintegrator areloop coupled insuchamannerthattheresulting relaxationoscillatorissuitableforverylowfre- quencyoperation. The sinewave outputistakenfroma pointCbetween thetriangularvoltageatpointBandtheaverage levelatpointD.There

41、sistancebetweenBandC isfixed,andthenetworkbetweenCandDisa OM OM OM EO A B C +SWITCHINGREF. 8+ .1 J- -0 Q OUTPUT -0 .1 AMPLIFIER -:.Y BI-STABLELINEAR f-+-+-+- .-.,OIFREQ.1 L-+-+-+-.-+-._-4_+_-B- +REF. TRIANGLE BI-STABLE CIRCUIT Figure3-4.SimplifiedLinearIntegrator theaveragelevelof theoutputcanbeadju

42、stedto exactlythe voltage midway between thereference levels.This control thenservesadequately toadjust thetriangularwave balance which inturnequalizes theon-offtimeofthesquarewave.Thesignals appearingattheplatesofthefirsttubeV15,are 180 0 outofphaseandnearlyequalinmagnitude. Thesesignalsarealsovery

43、nearlythedifference betweentheinputsonthetwogrids.Sincthere isnosignalontheleftgrid,theonlysignalinto the amplifieristhltatthejunctionofRandC,which istheconditionoriginallyrequired.Thesecond stageisa push-pullamplifieremploying thesignals fromtheplatesofthepreviousstage.Againthe common cathoderesist

44、anceisveryhigh, butthere isverylittledegenerationofthepush-pullinput. Thegainofthesystemtochangescommontoboth gridsisaboutone-halfwhilethegain tovoltages appearingbetween the inputgridsissomethingover 250.FinallyCisfedbacktothesignalgridfrom the cathode of Vl7A whichis180 0 outofphasewith thesignali

45、nput. 3-4SINE SYNTHESIZERANDFUNCTION SELECTORSWITCH Thetriangularwavefromthelinearintegratoris connectedtoR94.IntheSINEposition of the FUNC- TIoNselectorswitch(S3)theotherendof R94is connectedtothesinesynthesizingdiodesandto R93B, onehalfofthedualAMPLITUDEpotentio- meter.Thesynthesizedsinewavesignal

46、appears asthedifferencesignalbetweenpointsCandD, but anerrorsignal whichappearsatD withrespect toB-alsoappearsatCwithrespecttoB-.This cOmplsite signalisappliedtoa differential amplifier in the output circuit. Theplusandminusswitchingreferencesinthe bi-stableunitareadjustedsothattheratioofthe triangu

47、larwave amplitudetothe conduction voltages ofthe synthesizer diodes producestheleastdistortion ofthesinewave.Thisadjustmentalsofixesthe averagevoltageatCandisequaltotheaverage oftheplusandminusswitchingreferences. Thecathodefollowerisusedasanisolationstage betweentheintegratorandthebi-stablecircuit.

48、 Thiscompletestheoscillatingloop withitsinherent productionofbothsquareandtr.iangular functions. ThedcvoltagesatD,andthecathodeofV4are adjustedtobetheaverageoftheplusandminus switching references.Since these voltagesareequal thereisno change inDClevelapplied to the Output AmplifierastheAMPLITUDEcont

49、rolisvaried. Sect.ITIPage5 R59R23R22 -,. BI-STABLE UNIT LINEAR INTEGRATOR R94 S38 S3C R63 S30 V4 f-375VDCREG f225VDCREG R54+-r R93B R93A R95 r- - - - - -_-I f-225VDCREG. S3A 80-.628 f-75VDC REG. TOOUTPUT AMPLIFIER f-75VDC REG. B- Figure3-5.SineSynthesizerandFunctionSelector (A)Waveformfromintegratoroutput toB-.Triangular regardlessof functionselectorposition. (B)WaveformfromtoB-withselectorswitchinsine position.Notedistortionespeciallyatp