電子信息工程專業(yè)英語(yǔ)教程（第5版） 試卷與答案 試卷A

PAGEPagePAGE1ofNUMPAGES5TechnicalEnglishTestforElectronicInformationEngineeringDepartment____________Class___________Name____________Section123TotalScoreSECTION1Fillintheblankswithproperterms(30minutes).1真值表6基帶信號(hào)2信噪比7尋址模式3采樣保持電路8色度信號(hào)4混疊9軟件無(wú)線電5時(shí)隙10聲卡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.題號(hào)A卷答案1.01Truthtable1.02SNR：Signal-to-NoiseRatio1.03Sampleandholdcircuit1.04Aliasing1.05Timeslot1.06Basebandsignal1.07Addressingmode1.08Chrominancesignal1.09Softwareradio1.10Soundcard1.11數(shù)模轉(zhuǎn)換器1.12中央處理單元1.13實(shí)時(shí)操作系統(tǒng)1.14離散傅立葉變換1.15液晶顯示器1.16電荷耦合器件1.17印刷電路板1.18任意波形產(chǎn)生器1.19精簡(jiǎn)指令集計(jì)算機(jī)1.20數(shù)字萬(wàn)用表2.01所有處理器都可以完成數(shù)字信號(hào)處理任務(wù)。然而，專用數(shù)字信號(hào)處理器完成數(shù)字信號(hào)任務(wù)的效率和速度都是最好的。傳統(tǒng)的處理器遵循馮諾依曼結(jié)構(gòu)模型，該結(jié)構(gòu)模型采用一個(gè)單一的共享存儲(chǔ)器，同時(shí)存儲(chǔ)程序指令和數(shù)據(jù)；而數(shù)字信號(hào)處理器使用的是哈佛結(jié)構(gòu)或改進(jìn)哈佛結(jié)構(gòu)，該結(jié)構(gòu)包含多個(gè)程序和數(shù)據(jù)存儲(chǔ)器以及訪問(wèn)這些存儲(chǔ)器的多套總線。2.02IMT-2000網(wǎng)絡(luò)提供給用戶的基本業(yè)務(wù)有：1高質(zhì)量的語(yǔ)音傳輸；2.消息（取代電子郵件、傳真、短信、聊天等）3.多媒體（播放音樂(lè)，觀看錄像，電影，電視等）4.互聯(lián)網(wǎng)訪問(wèn)（網(wǎng)上沖浪，包括含音、視頻的網(wǎng)頁(yè)）2.03多數(shù)數(shù)碼相機(jī)采用的圖像傳感是一種電荷耦合器件（CCD）。一些低端相機(jī)采用CMOS技術(shù)。盡管將來(lái)CMOS傳感器一定會(huì)提高性能，并將更流行。然而，在高端數(shù)碼相機(jī)中，CMOS傳感器不太可能替代CCD傳感器