信息科学课后答案王朔中.docx

信息科学课后答案王朔中.docx

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信息科学课后答案王朔中

Unit1Exercises

（1）TranslatethefollowingsentencesintoChinese.

1.Aswithseriesresonance,thegreatertheresistanceinthecircuitthelowertheQand,accordingly,theflatterandbroadertheresonancecurveofeitherlinecurrentorcircuitimpedance.对于串联谐振，电路中的电阻愈大Q值就愈低，相应地线路电流或电路阻抗的谐振曲线也就愈平、愈宽。

2.Awirecarryingacurrentlooksexactlythesameandweighsexactlythesameasitdoeswhenitisnotcarryingacurrent.一根带电的导线其外表与重量都与不带电导线完全一样。

3.Clickmouseonthewaveformanddragittochangethepulserepetitionrate,ordirectlyenteranewvalueoftheperiodintheprovideddialoguebox,whilekeepingthepulsewidthunchanged.

在波形上点击鼠标并拖动来改变脉冲重复频率，或者在提供的对话框中直接输入新的周期值，而保持脉冲宽度不变。

4.Electronicsisthescienceandthetechnologyofthepassageofchargedparticlesinagas,inavacuum,orinasemiconductor.Pleasenotethatparticlemotionconfinedwithinametalonlyisnotconsideredelectronics.

电子学是一门有关带电粒子在气体、真空或半导体中运动的科学技术。

注意，在本书中粒子运动仅限于金属的情况不属于电子学。

5.Hardwaretechnologieshaveplayedvitalrolesinourabilitytouseelectronicpropertiestoprocessinformation,butsoftwareanddataprocessingaspectshavenotdevelopedatthesamespeed.

硬件技术在我们使用电子特性来处理信息的能力中一直起着重要作用，而软件及数字处理方面却没能与硬件同步发展。

6.However,inaproperlydesignedDCamplifiertheeffectoftransistorparametervariation,otherthanIco,maybepracticallyeliminatediftheoperationpointofeachstageisadjustedsothatitremainsinthelinearoperationrangeofthetransistorastemperaturevaries.

然而在设计得当的直流放大器中，若调节每一级的工作点使之在温度变化时保持在晶体管线性区，就能在实际上消除Ico以外的晶体管参数变化所造成的影响。

（2）Fillintheblankswiththemostappropriatechoice.

1.Amessagesignalcananyamplitudevaluebetween0andAvolts.

A.assumeB.useC.receiveD.accept

2.Eachtimeapositiveclockedgeoccurs,theflip-flopchangesstate,leadingtohalfasmanypulsesattheoutputtotheclockinput.

A.asB.comparedC.dueD.soas

3.Intheprevioussectionwediscussedsine-waveorCWmodulationsystemsinwhichthemodulatingsignal_______ofadigitalpulsetrain.

A.madeB.consistedC.containedD.got

4.Inthisbookweshallemphasizethelimitationsimposedontheinformationtransmittedbythesystemthroughwhichitwas_______andshallattemptsomecomparisonofdifferentsystems.

A.putB.traveledC.passedD.viewed

5.Thissignaleitherdoesnotchange,oritchanges______byanamountequivalenttooneormorequantumsteps.

A.interruptedlyB.rudelyC.abruptlyD.absolutely

6.Weshallonlybe_______withlogicalrepresentations,notabsolutevalues

A.interestedB.caringC.referredD.concerned

（3）Choosethephrasethatisclosestinmeaningtotheunderlinedpart.

1.Itisalltooeasywithlinearcircuits,whichappearrelativelysimplewhencomparedwithtoday’scomplexlogicarrangements,toignoredetailedperformanceparameterswhichcandrasticallyreducetheexpectedperformance.

A.whichhasbadinfluenceuponthesystemperformance

B.whichisimportanttoensurecircuitlinearity

C.whichispossibletoenhancethesystemperformance

D.whichiscrucialformaintainingthedesiredperformance

2.Thereforetherewillbeaslighttimedelay,duetothepropagationdelayoftheflip-flopsbetweenthetimeoneflip-flopchangesstateandthetimethenextonechangesstate,.,thechangeofstateripplesthroughthecounter,andthesecountersarethereforecalledripplecounters.

A.thestatechangeispropagatedthroughthecounterlikeripples

B.thestatechangescauseripplesinthecounter

C.passingthroughthecounter,thestateripplechanges

D.thestateofthecounterchangesduetoripples

3.Insteadoftriggeringoneachpulse,aphaselocktechniqueexaminestherelativephasebetweeneachoscillatorandmanyofitssyncpulsesandadjustsoscillatorfrequencysothattheaveragephasediscrepancyissmall.

A.checkseachoscillatorformanysyncpulses

B.checksthephaserelationshipbetweenindividualoscillatorsandacollectionofsyncpulses

C.looksattherelationsbetweenthephaseandthesyncpulses

D.examineswhetherthephaseisrelativetotheoscillatorandthesyncpulses

4.Bykeepingtheoffstateslightlybelowthreshold,thedelaybetweentheappliedelectricalpulseandtheresultingopticaloutputpulseisminimized;thisdelaymustindeednotbemorethanthebitintervalsothattheopticalpulsecanaccuratelyreproducetheinputsignal.

A.ensuringthatthesystemisoffthethresholdbyasmallmargin

B.maintainingthesystem’sshut-downstatesomewhatbelowaprescribedlevel

C.makingsurethesystemisbelowitsthresholdsothatthestateiskeptoff

D.keepingthesysteminashut-downstatethatisunderagivenlevelwithatinytolerance

5.Iftheoriginalsignaliswellbehaved,thelocaloscillatorwillneedverylittleinformationtobeabletotrack,andthatinformationcanbeobtainedbyaveragingforalongperiodoftime,therebyeliminatingnoisethatcouldbeverylarge.

A.theLOwillnotrequireanyinformationinordertokeeptracking

B.theLOwillmakeuseoftrackinginformationthatisscarceinthesystem

C.theLOwillrequiresomeinformation,butnotmuch,sothatthesystemcantrack

D.theLOwillusenoinformationotherthansomelittleonetomaintaintracking

6.Thethirdsectiondescribesquantizationschemesthattakeaccountofthecharacteristicsofspeech.

A.takemeasureofthespeechcharacteristics

B.takethespeechcharacteristicsintoconsideration

C.countthespeechcharacteristics

D.makeuseofthespeechcharacteristics

7.InaproperlydesignedDCamplifiertheeffectoftransistorparametervariationmaybepracticallyeliminatediftheoperatingpointofeachstageisadjustedsothatitremainsinthelinearoperationrangeofthetransistorastemperaturevaries.

A.theeffectivevariationofthetransistorparameters

B.theefforttochangetransistorparameters

C.thetransistorparametersthateffectivelychange

D.theresultscausedbytransistorparameterchanges

8.Stabilityandrepeatabilityarefundamentalattributesofdigitalcircuits,however,andthenecessaryaccuracycanbeobtainedinadigitalversionofthemodulatorbyanappropriatechoiceofwordlengthtorepresentthesignals.

A.byexpressingthesignalswithasuitablewordlength

B.byusingawordlongenoughtodescribethesignals

C.bychoosetocharacterizethesignalsintermsofwordlengthappropriately

D.byappropriatelyrepresentingthesignalstochoosealengthofwordsUnit2Exercises

（1）TranslatethefollowingsentencesintoChinese.

1.Ifanalogsignalsaretobetransmitteddigitally,theyfirsthavetobesampledataspecifiedrateandfurtherconvertedtodiscreteamplitudesamplesbyquantization.

2.如果要以数字方式传输模拟信号，首先必须以一定的频率对信号进行采样，然后通过量化进一步将它们转换为离散的幅度样本。

Linearfiltersamplifyorattenuateselectedspatialfrequencies,canachievesucheffectsassmoothingandsharpening,andusuallyformthebasisofre-samplingandboundarydetectionalgorithms.

3.线性滤波器放大或衰减选择的空间频率，能够实现像平滑和锐化这些效果，通常是重采样和边缘检测算法的基础。

Stabilityandrepeatabilityarefundamentalattributesofdigitalcircuits,however,andthenecessaryaccuracycanbeobtainedinadigitalversionofthemodulatorbyanappropriatechoiceofwordlengthtorepresentthesignals.

4.不过稳定性和可重复性是数字电路的基本性质，在数字式调制器中必要的精度可通过适当地选择代表信号的字长而获得。

Thefirstobservationismadeonthefundamentalrelationshipbetweenthenatureofsystemandtheperiodicityofitsfrequencyresponse:

acontinuoussystemhasanaperiodicfrequencyresponse,whileadiscretesystemhasaperiodicfrequencyresponse.

5.从系统性质和它频率响应的周期性之间的基本关系中首先可以看到：

连续系统有非周期性的频率响应，而离散系统有周期性的频率响应。

Themainfunctionofthereceiveristoextracttheinputmessagesignalfromthedegradedversionofthetransmittedsignalcomingfromthechannel.

接收器的主要功能是从由信道传输来的退化了的信号中提取出输入消息。

（2）Choosethewordorphrasethatisclosestinmeaningtotheunderlinedpart.

1.Roughlyspeaking,thetransistorcanbelikenedtoanelectronicallycontrolledvalvewherebyenergyappliedtooneconnectionofthevalveenablesenergytoflowbetweentwootherconnections.

A.related

B.linked

C.analogized

D.viewed

2.Whilethirdpartydesigntoolswereavailable,therewasnotaneffectivelinkfromthethirdpartydesigntoolstothelayoutandactualsemiconductorprocessperformancecharacteristicsofthevariousASICmanufacturers.

A.When

B.Although

C.As

D.Since

3.Thesesteps,implementedwithalevelofskillcommonintheindustry,almostalwaysproduceafinaldevicethatcorrectlyimplementstheoriginaldesign,unlessflawsarelaterintroducedbythephysicalfabricationprocess.

A.practicedusingskillsgenerallyavailableintheindustry

B.commonlyperformedatlevelsofskilledpersonnelintheindustry

C.realizedwiththeskillfulcommonlevelintheindustry

D.carriedoutbyskillscommonlyusedintheindustry

4.Asecondmajorstepwouldbetodevelopdesignspecificationsthatconsiderthefunctionalityofthehumanwiththesamedegreeofcarethathasbeengiventotherestofthesystem.

A.developdesignprocedurestoaccountforthehumanbehaviorandactivities

B.promotedesignarrangementsandtakethehumanfactorsintoconsideration

C.makeusedofdesignstepsthatrespectthehumanfunctionality

D.draftandeffectdesignrequirementsthattakeintoaccountthehumanfunctionality

5.Clickmouseonthewaveformanddragittochangethepulserepetitionrateordirectlyenteranewvalueoftheperiodintheprovideddialoguebox,keepingthepulsewidthunchanged.

A.simplytypeanewperiodvalueinthegivendialoguebox

B.directanentryforthenewperiodvaluetothedialoguebox

C.pointastraightforwardnewperiodvaluetothedialogueboxprovided

D.enteradirectiono