锁相技术译文翻译英文原文：AnOn-ChipAll-DigitalMeasurementCircuittoCharacterizePhase-LockedLoopResponsein45-nmSOI译文： 45纳米SOI全数字片上测量电路表征锁相环响应特性年级专业： 姓名： 学号： 2013 年 6 月 2 日英文中文AnOn-ChipAll-DigitalMeasurementCircuittoCharacterizePhase-LockedLoopResponsein45-nmSOIAbstractAnall-digitalmeasurementCircuit ,builtin45-nmSOI-CMOSenableson-chipcharacterizationofphase-lockedloop(PLL)responsetoaself-inducedphasestep. Thistechniqueallowsestimation ofPLLclosed-loopbandwidthandjitterpeaking.Thecircuitcan beusedtoplotstep-responsevs.time,measurestaticphaseerror, andobservephase-lockstatus.INTRODUCTIONManyapplicationssuchasPCIExpressrequireaPLLtoproducealow-jitterclockatagivenfrequencywhilemeetingstringentbandwidthandjitterpeakingrequirements.Process,voltage,andtemperature(PVT)variationsaswellasrandomdevicemismatchmakeitdifficulttoguaranteeanarrowrangeforPLLresponse.Forexample ,loopparameterssuchasVCOgain couldvarybymorethan2Xover PVTcorners.InFig.1,weseetheclosed-loopjittertransferfunctionsoftwoPLLswithidenticalreferenceclockandoutputfrequencies.OnePLLexhibitslargepeakingandlowbandwidthwhiletheothershowslittlepeakingbuthighbandwidth.Althoughdifferencesinthisexamplearemoreextremethanusual,similarbutsmallerdifferencesoftenresultfromPVTvariations. PLLresponseisoftenmeasuredonatestbenchusingsignalgenerators,oscilloscopes,and/orspectrumanalyzers.Forexample,thetransferfunctionsinFig.1wereautomaticallygeneratedbymodulatingthe100-MHzreferenceclockwithvariousfrequencieswhileobservingtheamplitudesoftheresultingoutputspurs.Suchmethods,whichmayrequiremanysecondstocomplete,motivatetheneedforfaster,lessexpensive,andpreferablyon-chiptechniquestocharacterizePLLresponse1-3.Fig.2showsthePLLoutputphasetransientresponsetoaninducedphasestep.Similartoothersecond-orderfeedbacksystems,thePLLtendstoovercorrect(orovershoot)asitworkstoeliminatetheinducedphaseerror.IfthePLLisunderdamped,asinthisexample,thePLLmayringseveraltimesbeforesettlingtoitsfinallockstate.AkeymetricinthePLLstep-responseiscrossover,definedhereasthe elapsedtimefrominputsteptoonsetofphaseovershoot.AnotherkeymetricisMaxOvershoot.It measuresthemaximumovercorrectioninthestepresponse.Transientsimulationsandclosed-formloopequations4showthatcrossoverisinverselyproportionaltothePLLs3dBclosed-loopbandwidth;thesmallercrossoveris,thehigherthebandwidth(Fig.3).Noticethatcrossoverislargelyindependentofthesizeofthephasestep.BothsimulationsandloopequationsalsopredictthatMaxOvershootisproportionaltothemaximumpeakingintheclosed-looptransferfunction;thelargerMaxOvershootis,thegreater thepeaking(Fig.4).Noticethatthemagnitudeoftheovershootisalsoproportionaltotheinputstepsize .Theserelationshipsbetweentime-andfrequency-domainbehaviorsallowustomakefasttime-domainmeasurementsandthenrelatetheresultsbacktofrequency-domainperformancespecifications. The circuit implementationpresentedinthispapershowsthatthePLLstepresponsemaybecapturedby anall-digital,on-chipfinitestatemachine,allowingforfastPLLcharacterization.SiliconresultsindicatethatthiscircuitcouldallowforPower-oncalibrationofthePLLbandwidthandpeakingforcompensationofprocessvariations.CIRCUITDESIGNThePLLundertest(Fig.5)isastandardinteger-Ncharge-pumpPLL.Theonlymodificationisthe additionofloopmeasurementcircuitry.Thefeedbackdivisor(N)isprogrammablefrom5to63，althoughN=8duringloopmeasurementtests.Thecharge-pumpcurrent,loop-filterresistance,andVCOgainareprogrammabletoallowforbandwidthandpeakingadjustmentsaswellasjitteroptimization.ThePLLbandwidthmaybeconfiguredfrom3to25MHzwhilethepeakingmaybevariedfrom4dB.TheVCOoperatesfrom1.6to5GHz.Theexpectedreferenceclockfrequency range is100to200MHz.Asimplewaytoinducethe requiredinputphasestepistoflipthepolarityofthereferenceclocksoitsphaseisadvancedbyhalfaclockcycle.Adisadvantagetothisapproachisthat themagnitudeofthephasestepisdependentonthereferenceclockdutycycle.Thisisundesirablebecauseovershoottestsrequire alargeandpredictableinputphasestep.Instead,thecircuitimplementationpresentedheremanipulatesthefeedbackdivisortoinduceaknownphasestep.Thecircuitthenautomaticallymeasuresthe resultingcrossoverandMaxOvershoot.Fig.6showsablockdiagram oftheloopmeasurementtestcircuit.Itincludesthreemainunits:control,crossoverdetector,a