电子信息工程专业英语教程（第5版） 试卷与答案 试卷A

PAGEPagePAGE1ofNUMPAGES5TechnicalEnglishTestforElectronicInformationEngineeringDepartment____________Class___________Name____________Section123TotalScoreSECTION1Fillintheblankswithproperterms(30minutes).1真值表6基带信号2信噪比7寻址模式3采样保持电路8色度信号4混叠9软件无线电5时隙10声卡11DAC16CCD12CPU17PCB13RTOS18AWG14DFT19RISC15LCD20DMMSECTION2TranslatethefollowingpassagesintoChinese(40minutes).Digitalsignalprocessingtaskscanbeperformedbyallprocessors.Specializeddigitalsignalprocessors(DSPs),however,performthesetasksmostefficientlyandmostquickly.WhiletraditionalprocessorsfollowtheVonNeumannarchitecturemodel,whichassumesasharedsinglememorytobeusedforbothprograminstructionsanddata,DSPsusetheHarvardormodifiedHarvardarchitecture,whichincludesmultipleprogramanddatamemories,alongwithmultiplebusestoaccessthem.ThebasicservicesthattheIMT-2000networkissupposedtoprovidetoitsusersare:1.High-qualityvoicetransmission.2.Messaging(replacinge-mail,fax,SMS,chat,etc.).3.Multimedia(playingmusic,viewingvideos,films,television,etc.).4.Internetaccess(Websurfing,includingpageswithaudioandvideo).TheimagesensoremployedbymostdigitalcamerasisaCCD.Somelow-endcamerasuseCMOStechnology.WhileCMOSsensorswillalmostcertainlyimproveandbecomemorepopularinthefuture,theyprobablywon'treplaceCCDsensorsinhigher-enddigitalcameras.Makesurethecamerahastherightresolutionforyourneeds.Ifyouaregoingtotakesnapshotsande-mailthemtofriends,thenyoudon'tneedanythingmorethan640x480pixelresolution.Buyingtheresolutionthatyouneedletsyousavemoney(andharddiskspace).Ontheotherhand,ifyouwanttoprintenlargedversionsofyourphotos,you'llneeda2-megapixelor3-megapixelcamera.SECTION3Readthefollowingpassagesandanswerquestions(30minutes).PassageoneCD-qualityaudiorequiresatransmissionbandwidthof1.411Mbps.Clearly,substantialcompressionisneededtomaketransmissionovertheInternetpractical.Forthisreason,variousaudiocompressionalgorithmshavebeendeveloped.ProbablythemostpopularoneisMPEGaudio,whichhasthreelayers(variants),ofwhichMP3(MPEGaudiolayer3)isthemostpowerfulandbestknown.LargeamountsofmusicinMP3formatareavailableontheInternet,notallofitlegal,whichhasresultedinnumerouslawsuitsfromtheartistsandcopyrightowners.MP3belongstotheaudioportionoftheMPEGvideocompressionstandard.Audiocompressioncanbedoneinoneoftwoways.InwaveformcodingthesignalistransformedmathematicallybyaFouriertransformintoitsfrequencycomponents.Theamplitudeofeachcomponentisthenencodedinaminimalway.Thegoalistoreproducethewaveformaccuratelyattheotherendinasfewbitsaspossible.Theotherway,perceptualcoding,exploitscertainflawsinthehumanauditorysystemtoencodeasignalinsuchawaythatitsoundsthesametoahumanlistener,evenifitlooksquitedifferentonanoscilloscope.Perceptualcodingisbasedonthescienceofpsychoacoustics—howpeopleperceivesound.MP3isbasedonperceptualcoding.Thekeypropertyofperceptualcodingisthatsomesoundscanmaskothersounds.Imagineyouarebroadcastingalivefluteconcertonawarmsummerday.Thenallofasudden,acrewofworkmennearbyturnsontheirjackhammersandstarttearingupthestreet.Noonecanhearthefluteanymore.Itssoundshavebeenmaskedbythejackhammers.Fortransmissionpurposes,itisnowsufficienttoencodejustthefrequencybandusedbythejackhammersbecausethelistenerscannothearthefluteanyway.Thisiscalledfrequencymasking—theabilityofaloudsoundinonefrequencybandtohideasoftersoundinanotherfrequencybandthatwouldhavebeenaudibleintheabsenceoftheloudsound.Infact,evenafterthejackhammersstop,theflutewillbeinaudibleforashortperiodoftimebecausetheearturnsdownitsgainwhentheystartandittakesafinitetimetoturnitupagain.Thiseffectiscalledtemporalmasking.Answerthefollowingquestionswithin50words.Q1:Whyisaudiocompressionneeded?Q2:Whatismp3?Q3:Whatdoesthewordpsychoacousticsmean?Q4:Whatistheaimofwaveformcoding?Q5:Whatisperceptualcoding?PassageTwoAlthoughover50yearsold,thestandardtelevisionsignalisstilloneofthemostcommonwaytotransmitanimage.Figure1showshowthetelevisionsignalappearsonanoscilloscope.Thisiscalledcompositevideo,meaningthatthereareverticalandhorizontalsynchronization(sync)pulsesmixedwiththeactualpictureinformation.Thesepulsesareusedinthetelevisionreceivertosynchronizetheverticalandhorizontaldeflectioncircuitstomatchthevideobeingdisplayed.Eachsecondofstandardvideocontains30completeimages,commonlycalledframes.Avideoengineerwouldsaythateachframecontains525lines,thetelevisionjargonforwhatprogrammerscallrows.Thisnumberisalittledeceptivebecauseonly480to486oftheselinescontainvideoinformation;theremaining39to45linesarereservedforsyncpulsestokeepthetelevision'scircuitssynchronizedwiththevideosignal.Determinethefollowingstatementistrue(T)orfalse(F):No.T/FStatementQ6:()Thetermcompositevideoisanaliasofstandardtelevisionsignal.Q7:()Therearemorethanonemethodsforvideotransmissionmentionedinthispassage.Q8:()Thecompositevideoisacombinationofframes,pictureinformationandsyncpulses.Q9:()Thenumber30frames/secondisalittledeceptive.Q10:()ThesyncpulsesareusedtocontrolthedeflectioncircuitsintheTVreceivers.题号A卷答案1.01Truthtable1.02SNR：Signal-to-NoiseRatio1.03Sampleandholdcircuit1.04Aliasing1.05Timeslot1.06Basebandsignal1.07Addressingmode1.08Chrominancesignal1.09Softwareradio1.10Soundcard1.11数模转换器1.12中央处理单元1.13实时操作系统1.14离散傅立叶变换1.15液晶显示器1.16电荷耦合器件1.17印刷电路板1.18任意波形产生器1.19精简指令集计算机1.20数字万用表2.01所有处理器都可以完成数字信号处理任务。然而，专用数字信号处理器完成数字信号任务的效率和速度都是最好的。传统的处理器遵循冯诺依曼结构模型，该结构模型采用一个单一的共享存储器，同时存储程序指令和数据；而数字信号处理器使用的是哈佛结构或改进哈佛结构，该结构包含多个程序和数据存储器以及访问这些存储器的多套总线。2.02IMT-2000网络提供给用户的基本业务有：1高质量的语音传输；2.消息（取代电子邮件、传真、短信、聊天等）3.多媒体（播放音乐，观看录像，电影，电视等）4.互联网访问（网上冲浪，包括含音、视频的网页）2.03多数数码相机采用的图像传感是一种电荷耦合器件（CCD）。一些低端相机采用CMOS技术。尽管将来CMOS传感器一定会提高性能，并将更流行。然而，在高端数码相机中，CMOS传感器不太可能替代CCD传感器