通信专业英语ppt.ppt

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1、ENGLISHONTELECOMMUNICATIONS课程名称：通信专业外语UNIT1ThePrincipleofPCM1234UNIT5IntroductiontoOpticalFiberCommunicationUNIT4InternetUNIT2AsynchronousSerialDataTransmission567UNIT10GSMUNIT8CellularMobileTelephoneSystemUNIT7WDMUNIT11CircuitSwitchingandPacketSwitchin

2、g11UNIT16CurrentSituationandtheFutureIntheTelecommunicationWorld161ThePrincipleofPCMUnit1ThePrincipleofPCMNEWWORDSANDPHRASESprinciplen.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．

3、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，手段overcomevt．克服，打败，征服environmentn．环境，周围情况

4、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，大地的bycomparison比较起来，相对之下parameter[pə'ræmitə]n．参数，系数technicalparameter技术参数

5、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)码器codecn．编译码器1ThePrincipleofPCMUnit1ThePrin

6、cipleofPCMNEWWORDSANDPHRASESinterleavevt．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.reoccurvi．再发生，再次发生1①PCMisdependentonthreeseparateoperations,sampling,quantizing,andc

7、oding.②Manydifferentschemesforperformingthesethreefunctionshaveevolvedduringrecentyears,andweshalldescribethemainones.③Inthesedescriptionsweshallseehowaspeechchanneloftelephonequalitymaybeconveyedasaseriesofamplitudevalues,eachvaluebeingrepresented,that

8、is,coded,asasequenceof8binarydigits.PASSAGEThePrincipleofPCM1④Furthermore,weshallprovethataminimumtheoreticalsamplingfrequencyoforder6.8kilohertz(kHz)isrequiredtoconveyavoicechanneloccupyingtherange300Hzto3.4kHz.⑤Practicalequipme