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通信专业英语.ppt


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通信专业英语.ppt
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MUNICATIONS课程名称:municationWorld161ThePrincipleofPCMUnit1ThePrincipleofPCMNEWWORDSANDPHRASESprinciplen.原理bedependenton依赖,取决于samplev.采样quantizev.量化,分层codev.编码n.码schemen.方案,设计,安排describevt.叙述,描述descriptionn.叙述,描述amplituden.幅,幅度binarya.二进制的minimumn.最小值,最小量1ThePrincipleofPCMUnit1ThePrincipleofPCMNEWWORDSANDPHRASEStheoreticala.理论上的repetitionn.重复,反复reexaminationn.再审查,重考maximumn.最大值reducevt.;vi.减少,缩小interchangey.互换,转换,相互影响methodn.方式.方法,evt.克服,打败,征服environmentn.环境,周围情况lightningn.电光,闪电,雷电strikev.击,敲,打sparkv.发火花,打火,闪光1ThePrincipleofPCMUnit1ThePrincipleofPCMNEWWORDSANDPHRASESignitionn.点火,点火装置signal-to-noiseratio信噪比satelliten.卫星terrestriala.地球的,地面的,parison比较起来,相对之下parameter[pə'ræmitə]n.参数,系数technicalparameter技术参数parameterestimation参数估计keyparameter关键参数1ThePrincipleofPCMUnit1ThePrincipleofPCMNEWWORDSANDPHRASESattenuationn.衰减,衰耗attenuationcoefficient衰减系数attenuationdistortion衰减失真inherenta.固有的,内在的assumevt.假设,假定decodern.解(译).编译码器1ThePrincipleofPCMUnit1ThePrincipleofPCMNEWWORDSANDPHRASESinterleavevt.交插,交错,插接appropriatea.适当的,合适的uniquea.惟一的,独特的uniquesolution唯一解Insomeways,eachofusislikeerveyperson;andinsomeways,eachofusisunique.urvi.再发生,再次发生1①PCMisdependentonthreeseparateoperations,sampling,quantizing,andcoding.②Manydifferentschemesforperformingthesethreefunctionshaveevolvedduringrecentyears,andweshalldescribethemainones.③Inthesedescriptionsweshallseehowaspeechchanneloftelephonequalitymaybeconveyedasaseriesofamplitudevalues,eachvaluebeingrepresented,thatis,coded,asasequenceof8binarydigits.PASSAGE1ThePrincipleofPCM1④Furthermore,weshallprovethataminimumtheoreticalsamplingfrequencyoforder6.8kilohertz(kHz)upyingtherange300Hzto3.4kHz.⑤Practicalequipments,however,normallyuseasamplingrateof8kHz,andif8-digitspersamplevalueareused,esrepresentedbyastreamofpulseswitharepetitionrateof64kHz.⑥Fig.1-1illustratesthesampling,quantizing,andcodingprocesses.PASSAGE1ThePrincipleofPCM 内容来自淘豆网www.taodocs.com转载请标明出处.