TechnicalEnglishUnit6PartIForInformationandDigitalAudioCompressionMPEGAudioLayer3CommunicationEngineeringNewWordsNewWords1advent到来，来临sampler样品multitude多数，大众amultitudeof…种种的，众多的WiththeadventoftheInternet,thereisadesireformoreandalbum照相簿，歌曲集amplitude幅度，广阔unsignedband未签约的乐队promote推销，促进moreinformationtobetransmittedacrossphonelines.Audioprecision精度，精确的stereo立体声rip撕，拉，劈royalty版税，庄严，王权informationisoneformthatisincreasinglydownloaded,beitmegabyte兆字节modem调制解调器clout权力，影响，力量spell拼写，迷住asamplerforaband’salbum,aradioprogram,orsoundasimperative势在必行的psycho-acoustic心理声学的advocate提倡者，拥护者stem阻止，堵住partofavideo.1Asbandwidthinatelephonewireislimited,pitch音调，程度threshold门限，阈值rival对手lax宽松的，不严格的thishasledtoaneedforinformation(includingaudio)tobemono单一，单声道bitrate比特率compressed.音频信息是一种愈来愈多被下载的编码比特字，比特码HuffmanencodingHuffmanbitcode（多媒体）形式，无论是乐队的唱片underestimate低估minority少数选曲，无线电节目，还是视频伴音。mainstream主流genre流派，类型3451222Thetraditionalmethodofstoringdigitalaudio,usedinCDsTheprecisionoftheamplitudeisdeterminedbythenumberofWhenweknowthesethreethings,thememoryusedbecomesanddigitalTV,samplestheamplitudeofthesoundasetbitsusedtostoretheamplitude.Sothebandwidth(ormemory)simpletocalculate:2numberoftimespersecond,andrecordsthis.2consumedbytheaudiosignalisdependentonthreefactors:Memory=Frequency×BitDepth×Time.thenumberofsamplestakenpersecond(Frequency),thethenumberofsamplestakenpersecond(Frequency),theAdditionally,ifthesignalisinstereo,thenthismustbenumberofbitsusedtostoretheamplitude(BitDepth)andthe用于CD和数字电视中存储数字音频doubledastwosignalsareinfactused.的传统方法是每秒抽取并记录一定lengthofthesignal(Time).次数的声音幅度值。如果信号是立体声的，内存就每秒钟的采样次数（频率），用于乘以二，因为立体声实际上用存储幅度的比特位数（比特深度）了两个信号以及信号的长度（时间）678334ThecodecThisequationcanbeusedtodemonstratewhytransmittingAstandard56kbpsmodemwouldtake84,672,000/57344=Thehumanearcanonlyhearalimitedrangeoffrequencies.high-qualityaudioacrosstheInternetrequirescompression.1477secondsorabout25minutes!25minutesisalongtimetoThecodecthereforeremovesallsoun