Lesson FliFlo电子技术专业英语教程

Unit7DigitalLogicCircuit12/8/20221《电子技术专业英语教程》Lesson20Flip-FlopBackgroundsTexttour

LanguageinuseVocabularyStructureReading/writingtechniques12/8/20222《电子技术专业英语教程》Terminologymultivibrator

n.【计】多谐振荡器fieldeffecttransistor 【计】场效应晶体管shiftregister 移位寄存器 Backgrounds12/8/20223《电子技术专业英语教程》TexttourOutlineFlip-flopFlip-flop’sinventionSimpleflip-flopsClockedflip-flopsThetypeofflip-flopsSet–resetflip-flops(SRflip-flops)

Triggerflip-flops(Tflip-flops)JKflip-flopDflip-flop12/8/20224《电子技术专业英语教程》Flip-flopIndigitalcircuits,aflip-flopisatermreferringtoanelectroniccircuit(abistablemultivibrator)thathastwostablestatesandtherebyiscapableofservingasonebitofmemory.Today,thetermflip-flophascometomostlydenotenon-transparent(clockedoredge-triggered)devices,whilethesimplertransparentonesareoftenreferredtoaslatches;however,asthisdistinctionisquitenew,thetwowordsaresometimesusedinterchangeably.Aflip-flopisusuallycontrolledbyoneortwocontrolsignalsand/oragateorclocksignal.Theoutputoftenincludesthecomplementaswellasthenormaloutput.Asflip-flopsareimplementedelectronically,theyrequirepowerandgroundconnections.12/8/20225《电子技术专业英语教程》Flip-flop’sinventionThefirstelectronicflip-flopwasinventedin1918byWilliamEcclesandF.W.Jordan.ItwasinitiallycalledtheEccles-Jordantriggercircuitandconsistedoftwoactiveelements.Thenameflip-flopwaslaterderivedfromthesoundproducedonaspeakerconnectedtooneofthebackcoupledamplifiersoutputsduringthetriggerprocesswithinthecircuit.Thisoriginalelectronicflip-flop——asimpletwo-inputbistablecircuitwithoutanydedicatedclocksignalwastransparent,andthusadevicethatwouldbelabeledasa"latch"inmanycirclestoday.12/8/20226《电子技术专业英语教程》Simpleflip-flopsSimpleflip-flopscanbebuiltaroundapairofcross-coupledinvertingelements:vacuumtubes,bipolartransistors,fieldeffecttransistors,inverters,andinvertinglogicgateshaveallbeenusedinpracticalcircuits-perhapsaugmentedbysomegatingmechanism.Themoreadvancedclockeddevicesarespeciallydesignedforsynchronoussystems;suchdevicesthereforeignoreitsinputsexceptatthetransitionofadedicatedclocksignal.Thiscausestheflip-floptoeitherchangeorretainitsoutputsignalbaseduponthevaluesoftheinputsignalsatthetransition.Someflip-flopschangeoutputontherisingedgeoftheclock,othersonthefallingedge.12/8/20227《电子技术专业英语教程》Clockedflip-flopsClockedflip-flopsaretypicallyimplementedasmaster-slavedeviceswheretwobasicflip-flops(plussomeadditionallogic)collaboratetomakeitinsensitivetospikesandnoisebetweentheshortclocktransitions;theyneverthelessalsooftenincludeasynchronousclearorsetinputswhichmaybeusedtochangethecurrentoutputindependentoftheclock.12/8/20228《电子技术专业英语教程》Thetypeofflip-flopsFlip-flopscanbefurtherdividedintotypesthathavefoundcommonapplicabilityinbothasynchronousandclockedsequentialsystems:theSR("set-reset"),D("data"or"delay"),

T("trigger"),andJKtypesarethecommonones;allofwhichmaybesynthesizedfromothertypesbyafewlogicgates.Thebehaviorofaparticulartypecanbedescribedbywhatistermedthecharacteristicequation,whichderivesthe"next"(i.e.,afterthenextclockpulse)output,Qnext,intermsoftheinputsignal(s)and/orthecurrentoutput,Q.12/8/20229《电子技术专业英语教程》Set–resetflip-flops(SRflip-flops)ThefundamentallatchisthesimpleSRflip-flop,whereSandRstandforsetandresetrespectively.Itcanbeconstructedfromapairofcross-coupledNANDorNORlogicgates.ThestoredbitispresentontheoutputmarkedQ.SRFlip-FlopoperationCharacteristictableExcitationtableSRActionQ(t)Q(t+1)SRAction00Keepstate000xNochange01Q=00110Set10Q=11001Reset11Unstablecombination11x0Nochange12/8/202210《电子技术专业英语教程》Set––resetflip-flops(SRflip-flops)Normally,instoragemode,theSandRinputsarebothlow,andfeedbackmaintainstheQandoutputsinaconstantstate,withthecomplementofQ.IfSispulsedhighwhileRisheldlow,thentheQoutputisforcedhigh,andstayshighevenafterSreturnslow;similarly,ifRispulsedhighwhileSisheldlow,thentheQoutputisforcedlow,andstayslowevenafterRreturnslow.Figure20-1showsthesymbolforaSRlatch.Figure20-1ThesymbolforaSRlatch12/7/202211《电电子子技技术术专专业业英英语语教教程程》》Triggerflip-flops(Tflip-flops)IftheTinputishigh,theTflip-flopchangesstate("toggles")whenevertheclockinputisstrobed.IftheTinputislow,theflip-flopholdsthepreviousvalue.Thisbehaviorisdescribedbythecharacteristicequation:(or,withoutbenefitoftheXORoperator,theequivalent:)andcanbedescribedinatruthtable:TFlip-FlopoperationCharacteristictableExcitationtableTQQnextCommentQQnextTComment000holdstate000Nochange011holdstate110Nochange101toggle011Complement110toggle101Complement12/7/202212《电子技术术专业英语语教程》Triggerflip-flops(Tflip-flops)Figure20-2showsT-typeflip-flop.WhenTisheldhigh,thetriggerflip-flopdividestheclockfrequencybytwo;thatis,ifclockfrequencyis4MHz,theoutputfrequencyobtainedfromtheflip-flopwillbe2MHz.This'divideby'featurehasapplicationinvarioustypesofdigitalcounters.ATflip-flopcanalsobebuiltusingaJKflip-flop(J&KpinsareconnectedtogetherandactasT)orDflip-flop(TinputandQpreviousisconnectedtotheDinputthroughanXORgate).Figure20-2T-typeflip-flop12/7/202213《电子技术术专业英语语教程》JKflip-flopTheJKflip-flopaugmentsthebehavioroftheSRflip-flop(J=Set,K=Reset)byinterpretingtheS=R=1conditionasa"flip"ortogglecommand.Specifically,thecombinationJ=1,K=0isacommandtosettheflip-flop;thecombinationJ=0,K=1isacommandtoresettheflip-flop;andthecombinationJ=K=1isacommandtotoggletheflip-flop,i.e.,changeitsoutputtothelogicalcomplementofitscurrentvalue.SettingJ=K=0doesNOTresultinaDflip-flop,butrather,willholdthecurrentstate.TosynthesizeaDflip-flop,simplysetKequaltothecomplementofJ.TheJKflip-flopisthereforeauniversalflip-flop,becauseitcanbeconfiguredtoworkasanSRflip-flop,aDflip-flop,oraTflip-flop.NOTE:Theflipflopispositiveedgetriggered(ClockPulse)asseeninFigure20-3.Figure20-3JKflip-flop12/7/202214《电子技技术专业业英语教教程》JKflip-flopThecharacteristicequationoftheJKflip-flopis:andthecorrespondingtruthtableis:JKFlip-FlopoperationCharacteristictableExcitationtableJKQnextCommentQQnextJKComment00Qprevholdstate000xNochange010reset111xset101set10x1reset11toggle11x0Nochange12/7/202215《电子技技术专业业英语教教程》Dflip-flopTheQoutputalwaystakesonthestateoftheDinputatthemomentofarisingclockedge(orfallingedgeiftheclockinputisactivelow).ItiscalledtheDflip-flopforthisreason,sincetheoutputtakesthevalueoftheDinputorDatainput,andDelaysitbyoneclockcount.TheDflip-flopcanbeinterpretedasaprimitivememorycell,zero-orderhold,ordelayline.Figure20-4showsDflip-flop.Figure20-4Dflip-flop12/7/202216《电子技术专专业英语教程程》Dflip-flopTruthtable:clockDQQprevRisingedge00xRisingedge11xNonrisingxQprevTheseflipflopsareveryuseful,astheyformthebasisforshiftregisters,whichareanessentialpartofmanyelectronicdevices.TheadvantageoftheDflip-flopovertheD-typelatchisthatit"captures"thesignalatthemomenttheclockgoeshigh,andsubsequentchangesofthedatalinedonotinfluenceQuntilthenextrisingclockedge.Anexceptionisthatsomeflip-flopshavea'reset'signalinput,whichwillresetQ(tozero),andmaybeeitherasynchronousorsynchronouswiththeclock.12/7/202217《电子技术术专业英语语教程》VocabularyAcquisitionstimulusmarginevaluationancillarybriefStructureReading/writingtechniquesLanguageinuse12/7/202218《电子子技术术专业业英语语教程程》Vocabulary12/7/202219《电子子技术术专业业英语语教程程》AcquisitionindictionaryTheactofacquiring.获得，，取得得Somethingacquired,especiallyanadditiontoanestablishedcategoryorgroup.获得物物Theprocessoflocatingasatellite,guidedmissile,ormovingtargetsothatitstrackororbitcanbedetermined.搜索，，探测测12/7/202220《电子子技术术专业业英语语教程程》AcquisitionintextAnacquisitioninstrument––usuallyanoscilloscopeorlogicanalyser–isprobablythefirstthingthatcomestomindwhenyouthinkaboutmakingelectronicmeasurements.当进行行电子子测量量时，，人们们首先先想到到的很很可能能是一一件采采集仪仪器——通常是是示波波器或或逻辑辑分析析仪。。12/7/202221《电子子技术术专业业英语语教程程》Acquisitioninuseaircrafttargetacquisition空中目目标的的搜索索high-speeddataacquisition高速数数据采采集languageacquisition语言习习得techniqueacquisition技术引引进12/7/202222《电子子技术术专业业英语语教程程》StimulusindictionarySomethingcausingorregardedascausingaresponse.刺激因因素Anagent,anaction,oraconditionthatelicitsoracceleratesaphysiologicalorpsychologicalactivityorresponse.刺激物物12/7/202223《电子子技术术专业业英语语教程程》StimulusintextThetoolsetfordigitaldesigncharacterizationdiffersfromitscounterpartinanalog/mixedsignaldesign,butbothmustincludestimulusinstrumentsandacquisitioninstruments.Thesignalsource,orsignalgenerator,isthestimulussourcethatpairswithanacquisitioninstrumenttocreatethetwoelementsofacompletemeasurementsolution.用于数数字设设计特特性评评价的的测量量仪器器和用用于模模拟/混合信信号设设计的的测量量仪器器是不不一样样的，，但两两者一一定都都包含含激励励信号号产生生仪器器和信信号采采集仪仪器。。信号号源（（或信信号发发生器器）和和采集集仪器器是构构成一一个完完整测测量解解决方方案的的两大大基本本组成成部分分。12/7/202224《电子子技术术专业业英语语教程程》StimulusinuseunderthestimulusofthishopeLightisastimulustogrowthinplants.12/7/202225《电子技技术专业业英语教教程》MarginindictionaryAnedgeandtheareaimmediatelyadjacenttoit;aborder.边缘，边边界Theblankspaceborderingthewrittenorprintedareaonapage.空白Alimitinaconditionorprocess,beyondorbelowwhichsomethingisnolongerpossibleoracceptable:极限themarginofrealityhascrossedthemarginofcivilizedbehavior.12/7/202226《电子技术术专业英语语教程》MarginindictionaryAnamountallowedbeyondwhatisneeded:余地Ameasure,quantity,ordegreeofdifference:差数Theminimumreturnthatanenterprisemayearnandstillpayforitself.边际收益Theborderofaleaf.树叶的边缘缘12/7/202227《电子技术术专业英语语教程》MarginindictionaryIntelegraphy,ameasureoftheabilityofthereceivingapparatustocopywithtimingerrorsinthereceivedsignal.Inprinting,thespacesurroundingthetypearea,comprisinghead,tail,backandforedge.12/7/202228《电子技术术专业英语语教程》MarginintextTociteanotherexample,engineersmustcharacterizetheiremergingdesignstoensurethatthenewhardwaremeetsdesignspecificationsacrossthefullrangeofoperationandbeyond.Thisisknownasmarginorlimittesting.举另外一个个例子。为为了确保新新硬件在整整个操作范范围及该范范围之外满满足性能设设计要求，，工程师们们必须对即即将完成的的设计进行行特性评价价。这就是是所谓的““边缘测试试或极限测测试”。12/7/202229《电电子子技技术术专专业业英英语语教教程程》》Margininusebyacomfortablemargin以较较大大的的多多数数byanarrowmargin以微微弱弱多多数数bya...margin以...之之差差12/7/202230《电电子子技技术术专专业业英英语语教教程程》》Margininusebindingmargin装订订边边continentalmargin大陆陆边边缘缘currentmargin工作作电电流流范范围围,电电流流容容限限designmargin设计计余余量量errormargin误差差容容限限12/7/202231《电子子技术术专业业英语语教程程》Margininuselowlevelnoisemargin低电平平噪声声容限限magnitudemargin幅值裕裕度noisemargin噪声容容限,噪噪声安安全系系数nominalmargin标称容容限peakmargin峰值容容限12/7/202232《电子子技术术专业业英语语教程程》EvaluationindictionaryAprocesstodeterminewhetherornotanitemofhardwareorsoftwarecanperformaparticularrequiredfunctionortodeterminewhichoftwoormoreitemscanperformthefunctionbest.评价；；鉴定定Aprocesstoreduceanexpressiontoitssimplestformorasinglevalue.计算，，求值值12/7/202233《电子子技术术专业业英语语教程程》EvaluationintextAsignalsourceisnothinglessthanthecornerstoneofalmostanyinstrumentationsetupusedinhardwaredesign,debug,orevaluationprojects信号源源是用用于硬硬件设设计、、调试试、评评价工工程中中的几几乎任任何一一种测测量配配置的的基础础。12/7/202234《电子技技术专业业英语教教程》Evaluationinuseaccomplishmentevaluation学业成绩绩评定hazardevaluation危害评价价lossevaluation损耗估算算evaluationofdeterminants行列式的的求值12/7/202235《电子技技术专业业英语教教程》AncillaryindictionarySubordinate:从属的Auxilia