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，i.e.，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。

enteradirectionofanewperiodvaluetopro