HP-3780A-Manual 电路图.pdf

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1、 HP Archive This vintage Hewlett Packard document was preserved and distributed by www. Please visit us on the web ! On-line curator: Louis Taber RadioFans.CN 收音机爱 好者资料库 OPERATING MANUAL PATTERNGENERATOR/ ERRORDETECTOR 3780A .CJ-_0 ,-,:.-. u._-.,:JI!C-:_: 0 - _.;:.-:-. -.- 0oj .BINARYERROR rLSIGNAL

2、EXAMPLE 1showshow.single bit lostintransmission can resultintwocodeerrors and one binary error. CLOCK PATTERN GENERATOR RZBINARY GENERATED oooo OUTPUT HDB3CODED 1 1BITLOSTIN- TRANSMISSION-.-, o I- ooV ERROR DETECTOR RECEIVED HDB3 DECODED SIGNAL o000 CODE ERROR t-BINARY-+l. ERRORS EXAMPLE2 showshowa

3、single bit lostintransmission can result in one code error andtwobinary errors 9 10 15continuedfromPage8. PatternSe*tionThreemaximallengthpseudorandombinarysequences (PRSS)oflength511,32767and1048575bitsandfivefour bitrepetitivewordpatternsareproduceclbythegenerator. ThePRBSgeneratormayalsobeusedtog

4、eneraterandomreo petitivewordpanernsoflength9,15or20bits. Option001providesafrontpanelprogrammable,16bitword in placeofthefivefour-bitandrandomrepetitivewordpat terns. This can also providetwo8bitwordsalternatedbyan externalsignalappliedviathereafpanel. Upto999zeros canbeaddedoncepersequencetoalloft

5、he selectablepatterns. When ttle PABS/WORDswitchofthereceivinginstrument issettooneofthePABSpositions,orwhentheinternal SYSTEMATICERRORDETECTIONswitchA37S2issetto OFF,theerrordetectorautomaticallyrecognisesandrepro- ducesasynchronouserrorfreeversionofanyPRBSorWORD patternproducedbythegenerator.Thisi

6、ncludesPRBS butexcludesanypatterncontainingaddedzerosoralter- natingwords(Options001or003). InstrumentsaresuppliedwiththeinternalSYSTEMATIC ERRORDETECTIONswitch,A3752,settotheON position.InthismodethereferenceWORDofthereceiving instrumentcanbepresettooneofthefixed4bitwords,or withOptions001or003toth

7、e16bitword.Thisis achievedbysettingthePRBS/WORDswitchofthereceiving instrumenttotheappropriate4bitword,orwithOptions 001or003bysettingthePRBS/WORDswitchto16and selectingtheappropriatewordwiththeWORDSELECT switches.Systematicerrorsonthe4or16bitwordswill thenresultinsynclossatthereceivinginstrument. A

8、typicalexampleoftheuseofsystematicerrordetection inanendtondmeasurementis givenbelow: Ifthetransmittedword1100isrepeatedlyreceivedas1000 astheresultofasystematicfault,thenthefollowing resultswillbeobtainedwiththereceivinginstrument. PRBSlWORD switchsetting (receivinginstrument) 9,150r20 1000 1100 RE

9、SULT NOERRORSWORD-.- , NOERRORSWORD ERRORSSYNCLOSS., Data andClock Format An indication of receive pattern lockisgiven by LED lamps. A manual override ontheautomaticsyncisprovided which forces a syncloss;when released the instrument revertsto automaticsynchronisation. The generator testpatternmay be

10、 producedinbinaryRZor NRZ,orternary. HDB3orHDB2 formats. When operating inbinaryformata second binaryoutputisavailable whichis 6bits advanced onthemaindataoutput.Thereceiverdatain- putformat selectionisindependentofthegenerator controls. CLOCKorCLOCK may be selected independently on genera- toroutpu

11、tand receiver input. A choiceoftrigger thresholdisprovidedonclock anddata inputs allowingcontinuousorburstmodeoperation. Indica- tionofsignal triggeringisgivenbyLED lamps. Error CounterControloferrorcountertimebase may be internal over106, Controland Display 108or1010clock periods, manualviastart/st

12、oppushbuttons orexternal viatheprinteroutputconnector. Internal error counts are displayed as a scaled SER readingintheformX.Y x10-n. Errorcountsover a manually or externallycontrolled timebase are displayed as a scaled COUNT readingintheform X.Yx10+n. Frequency offsetisdisplayed as a fractionofthe

13、nominal centre frequencyintheformXVx10-nwhere n6usually. The display uses seven segment LED characters. Flags SelfCheck TriggerOutputs Indicationsofmeasurement gating,syncloss andcountover- flow are provided byLEDlamps. An indicationisalso givtln ifthelast measurement resultisbased on lessthan100err

14、ors. Note:Syncloss appliestobinarymeasurementsonly.Sync lossdoesnotapplytocodeerrorandfrequency offsetmeasurementsandthesyncloss flag istherefore inhibitedinthesemeasurementmodes. A fixed binary error rateof10-2may be injected intothe test patterninordertochecktheerrordetectorfunctions. This facilit

15、yismutually exclusive with zero add and also doesnotapplytocode error and frequency offset measure- ments. A triggeroutput,giving one transition per sequence, is avail- able from afrontpanel socketonthegenerator. Theoutput ismodified during zero addtoallow examinationofthezero blockorthpatternimmedi

16、ately following it on an oscillo- scope. The receiver section also provides a triggeroutput,(for PRBS only) givingonepulse per sequence, from a rear panel socket. 11 ErrorDetector Outputs 116 OPTIONS 12 Inadditiontoreceivertriggerandclockoutputs,thereare threeoutputswhichcanbeusedtoevaluateerrordist

17、ribu- tion.These are anerroroutputgiving one pulsepererror,a BCDprinteroutputand a pen recorderoutput. Option001 providesfrontpanelprogrammable16bitortwo 8bitwordsasdescribedinSection2-11. Option002provides small Siemensconnectorsonallexter- nal75ohmsinterfaces in placeofBNCconnectors. Option003isac

18、oni:linationofoptions001 and002. Option099deletesfrequencyoffsetgeneration. Options100-102providedifferentcrystalfrequenciestothose fittedinthestandardinstrumentasfollows:- STANDARD OPTION100 OPTION101 OPTION102 2048,8448and1536kHz 2048,8448and34368kHz 1544,6312and44736kHz 1544,6312and3152kHz 117 ME

19、ASUREMENT CONFIGURA TIONS Inthecaseofoptions101 and102,theHDB3/HDB2codec is replacedbyaB6ZS/B3ZScodec. Therearetwobasicmeasurementconfigurationsforthe 3780APatternGenerator/ErrorDetector,these areloop backandendtoend.Withloopback measurementsthe sameinstrumentisusedforbothsignalgeneration and measur

20、ement.Withendtoend measurementstwoinstru- ments are usedonetotransmitthetestpatternthrougha channelundertestandanotherattheremoteterminalto make measurements.Theitemundertestmaybe acomplete transmission systemorindividualsystemcomponents. Note:When theendtoendconfigurationisused theMEAS- UREMENTswit

21、chofthesendinginst(umentshould notbe settoFREOOFFSETasthiscouldintroduce jitteron thetransmittedsignal. TYPICAL CONFIGURATIONS 3780ALOOPt -0-:q 7 ITEM . UNDER - - - TEST (l=iii I DATA I DATA 3780A LOOPBACKCONFIGURAnON (USINGRECOVEREDCLOCK) 3780A 0- 0- ITEM 0_000 - - 7 l!Sf=: . UNDER . 0- - . - - - T

22、EST- - .-z-.-z-, I CLOCK II CLOCK I DATADATA END TO ENDCONFIGURATION 3780A3780A 0-:q - - ITEM -7_ . UNDER-. 0- - 0-:= - TEST lil1iilI.li: 88.=. I DATA II DATA I ENDTOENDCONFIGURATION (USINGRECOVEREDCLOCKI 13 1-18 ACCESSORIES 14 Unbalanced/Balanced converters, Model155088 The model155088isa 7S,Q unba

23、lanced to 11onbalanced impedance converter having a frequencyrange1 -10MHz. Thefollowing example shows a typical application of the converter for making loop back measurementsona 110,Q balanced test item. LOOP 3780A ITEM -._000_ -_DO UNDER 0-: TEST .-=- DATA DATA OUTPUT INPUT lS5088I 7SOHMS UN8ALANC

24、EDr 110 OHMSBALANCED l 15508BI MEASUREMENTSON A110OHMBALANCEDTESTITEM CablepreamplifierModel15509A. Themodel15509Aisa cablepreamplifierwith75ninput and25dBgain, designedtoprovideaninterfacebetween a monitoroutputpointandthe3780APattern Generatorl ErrorDetector.Thepowersupplyforthepreamplifieris avai

25、lablefromfrontpanel socketsonthemodel3780A.The followingexamplesshowtypicalapplicationsofthecable preamplifier. 2Mb!.INTERFACE MONITOR POINT75n 3780A U !e:J! -0- I -. . - - )-zJ 75nUNBALANCED SOURCE - B 1 750n 15509Ar, r-. 3780A MONITOR POINT 75n -i_ 82n -. ? 0-.:.: (1 rh JJ)-Z.l 75nUN8ALANCED SOURC

26、E MEASUREMENTSATAMONITORPOINTON A2Mb!.INTERFACE 34Mb!INTERFACE MEASUREMENTSATAMONITORPOINTON A34Mb!.INTERFACE 15 16 -9SPECIFICATIONS Note:Alltransitiontimesrelateto10-9096ofpulse height.AllpulseMdthsspecifiedat50%pulseheight. GENERATOR InternalClock ClockOffset ExternalClock CJockOutput Panerns Freq

27、uency: Accuracy: Stability: Format: Jitter: Range: Frequency: Impedance: Triggering: Sensitivity: Amplitude: Indicator: Polarity: Impedance: Amplitude: DCOffset: TransitionTimes: Overshoot: Protection: PRSS, WORD ZeroAdd: ErrorAdd: Three crystalclocks1536,2048and 8448kHz. Betterthan3ppmatambient. Ty

28、picallybetterthan12ppmaOe to550C. Typicallybetterthan5ppm/year ageing. Square wave.506%dutycycle. Lessthan0.5%ofperiod+150ps) pk-pk; Continuouslyvariableuptoatleast 50ppmaboutinstalled crystalfre. Quencies;offsetcanbedisplayedin receiver. 1kHz- 5OMHz. 75ohmsnominaltoground. Automaticorgroundthreshol

29、d switch.min.pulsewidth(30%of period+2ns). Betterthan500mVpk-pk. 5Vpk-pkmax.limits5V. LEDilluminatedifclocktransitions present. CLOCKorCLOCKswitch. 75 ohmsnominaltogrou 3V0.3Vpk-pk. Space OV, mark3V. Lessthan 4ns. Lessthan10%ofpulseamplitude. Open/shortcircuitprotected,max. voltage6Vshortterm. Maxim

30、allength 29_1.215_1.2X)_1 randomlyselectable9.15.20bitse- Quence. 0000.1000,1010. 1100.1111fixed words. 1-999 zeros, variableinunitsteps. maybeaddedonceper sequenceto anypattern;zeroblockoccursbefore longestrunofzerosinmaximal length PRSS. 10-2binaryerrorratemaybe added toanypattern(,0 consecutive e

31、rrors addedevery1000clockperiodsl. DataFormat DataOutput Binary: Ternary: Codes: Impedance: Amplitude: DCOffset: TransitionTimes: Overshoot: Protection: NAZorRZ(506%widthonin- ternalclockI. RZAMIorcoded(SO 6%widthon internalclock). HDB3orHDB2(rear panelswitchl. 75ohmsnominaltoground. Binary3V0.3Vpkp

32、k. Ternary 4_74V 0.47Vpk.pk. Binaryspace OV, mark3V. Ternary space OV, mark 2.37V. Ratio01+veto-vepulseamplitude 1.00.05. Lessthan 40s. Lessthan 10%01pulseamplitude. Open/shortcircuitprotected,max. voltage 6Vshort term. Format: Relative Delay: OCOfuet DelayDataOutputBinaryonly. 6bitsadvanced onmaind

33、ataoutput Binaryspace OV 0.3V,mark3V 0.3V. Otherspecificationsasformaindataoutput. ClocklDataPhasing TrtggerOutput RECEIVER DataInput NRZData: RZData: Format: Position: Width: Impedance: Amplitude: TransitionTimes: Overshoot: Protection: Rate: Impedance: Triggering: Sensitivity: Amplitude: Indicator

34、: Rising edgeofclocknominallyin middleofdata. Clock and datanominallycoincide. Square wavewithonetransitionper wordorsequenee. TransitionsnominallycoinCIdentwith startofwordorbeforefirstzeroof longest zeroblockon PRBS. Equaltowordorsequence length,but outputheldatzeroduringzero add 50ohmsnominaltogr

35、ound. , V min. pk-pk. Lessthan 5ns. Lessthan 10%ofpulse amplitude. Open/shortcircuitprotected,max. voltage 5Vshortterm. 1Kb!, - 50Mb!, 75ohms nominaltoground Choiceofnominalthreshold 2OOmV, BOOmV,orground;min.pulsewidth (30%ofperiod+20sl. Better than500mVpkpk. 5Vpkpkmax.limits5V. LEDilluminatedifdat

36、a transitions present. 17 DataFormat Clode.Recovery ExternalClock Ckx:k!DataPhasing Patterns Synchronisation Binary: Ternary: Codes: Frequency: Mode: Frequency: Polarity: Impedance: Triggering: Sensitivity: Amplitude: Indicator: RecoveredClock: ExternalClock: PRBS andWORD: Indicators: Mode: Sync Los

37、s: Manual: ResyncTime: 18 NRZorRZ RZAMIorcoded. HDB3orHDB2(rear panelswitch commonwithgenerator). Atthethree internal ratesofgene- rator(selection switchcommonwith generator). Operates on any datainputprovided there aretwoormoretransitions every20bits(data lossinhibitsclock recoverycircuit). 1kHz-50

38、MHz CLOCKorCLOCKswitch. 75 ohms nominaltoground. Automaticorground threshold switch (commonwithgenerator), min. pulse width(30%ofperiod+2ns). Betterthan5CXJmVpk-pk. 5Vpk-pkmax.limits5V. LEDilluminatedifclocktransitions present. Automaticphasing. Rising edgeofclockshouldbenomi- nallyinmiddleofdata pu

39、lse (tYpic- ally30$internaldelayofclockre- lativetodata betweeninputsandsam- plingpoind. Allpatterns producedbygenerator excluding added zeros and alternating words; receiver also recognises PReS. LEDindicationofpatternlockfor PRSS, PRSS,WOROandALLONES! ZEROS (indicatorsinhibitedduring sync loss and

40、 code errororfrequency offsetmeasurements). Automaticwithmanual override. Greater thanapprox.20,000errorsin 5CXJ,OOOclockperiods. Sync override via pushbuttonforcing a sync loss. Typicallylessthan500bits. MeasurementsModes:Binaryerrors.cocJeerrors, frequency offset. BINARYERRORS: Closedloopbit-by-bi

41、tdetectionon anypattern producedbygenerator excluding added zeros andalternating words_ DisplayBER CODEERRORS, .MI: HDB3, HDB2/B3ZS BBZS, FREQUENCY OFFSET, Method: Gating: Format: Range: Accuracy: Detectedonanypatternaccordingto thefollowingruleswhere0cspace , markV=bipolarviolation. Bipolarviolatio

42、nsare code errors. 01V.10V.llV.OOOOandOl00Vare cooeerrors. 1v.000and010Varecodeerrors. OVO.1YO. 1Vl.OOVl ando00oooare cocle errors(seeoptions)lOOOOOOVl andQOOOClOVOproducea single code error). Measurementoffractionaloffsetof generatorclockoutputfrominstalled crystal rates. Totalises errors over sele

43、cted gating period andautomaticallyscales the answer. 106,108or1010clock. periods. re- petitive. X.Y xlO-nLED 0.0 x10-94.0 x10-2(binary errors). 0.0 x10-9-+9.9x10-2(code err- ors over1010clocksl. 0.0 x10-+1.0 x10-0(code err- ors over108clocks). 0.0 x 10-51.0 x10-(code err- ors over106clocks). Indica

44、tiongivenifmeasurement re- sult basedonlessthan100errors. COUNTMethod: Gating: Format: Range: FREQ.Method, OFFSET Gating: Format: Range: Accuracy: Totalises errors over selected gating period. Manualstart/stoppushbuttonswit- ches. Externalcontrolviaprinterout- put. X.YxlO+nLEDwithautomatic roundu. 0

45、.0 x101-+9.9X108 Countsdeviationfrequencyover106 clockperiodsofinternalstandard crystal rate. Automatic. XYx 1O-nwithautomaticround-up Upto25kHzdeviationfromnominal crystal rate. 1countrelativetotheinternal standard clocks. 19 STRDBBERmaximumrefreshment rate 2 Hz. Displaycontinuouslyupjatedwith roun

46、d-up when measurement ends. Flags(LEDsl PrinterOutput (rearpanel) Gating: SyncLoss: Overflow: 100Errors: Format: Flags: PrintModes: PrintCommand: Indicatesmeasurementinprogress, willextinguishforatleast500ms between measurements. Indicates local pattern reference has lostsync,displayblanksandmeasure

47、- mentisterminated(SER)orhalted (COUNT);flag remainslitforat least 500ms(SEAlorheld(COUNT) untilmeasurementisterminated. iSynclossinhibitedduringcode err- orandfrequencyoffsetmeasure- mentsl. Indicatesinternalerrororfrequency count109.displayblanksand measurementisterminated(SEA)or hatted(COUNT);fla

48、gremainslitfor atleast500msISEA)orheld (COUNT)untilmeasurementister- minated. Indicateslessthan100errorscounted duringlasterrormeasurement(inhibi- tedduringfrequencyoffsetmeasure. ments). 8421 BCD 10columns BEAF*XY10-N COUNTF*XYl0+N FVfor100errors F1foroverflow F2forsync loss F 3forclockloss F4forda

49、ta loss BEA-printcommand givenonter minationofmeasurement. COUNTMAN-printcommandgiven onSTOP commandfromfrontpanel COUNTEXT-printcommandgiven onSTOP commandfromprinter TTLpulse.min.printcycletime 5OOms. signal no errors signal plus errors sync loss signal loss 10-8 10-7 10- 10- 10-4 10- 10-2 nd(9)only. IntheERRORADDpositionafixedbinaryerrorrate of10-2isintroducedintothegenerator sequenceby producing10consecutive errorsinevery1000cloc