现代通信原理课件(英文版).ppt

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1、现代通信原理课件ChapterOne1IntroductionChapterOneWhy?InformationAgeInformationSuperhighway2Applicationmilitaryapplication;commonapplication;ChapterOne3Whatisacommunicationsystem?Communicationsystemsisusedtotransmitinformation.1.1Introduction4Keyconceptionsorwords(1

2、)Information;(2)Message;(3)Signal;(4)Waveforms1.1Introduction51JimesC.Maxwell（1864）2HeinrichHertz（1887）ClaudeE.Shannon(1948)4.Winner1.1Introduction6PerspectiveofcommunicationWireoptic-fiberandnetworkswireless1G->2G->3G->B3GWLAN;MIMOandMIMO-OFDM,UWB,optic–wi

3、relesscommunication1.1Introduction7Whatmustbeconsideredwhenyoudesignacommunicationsystem?1.Selectionoftheinformation-bearingwaveform2.Bandwidthandpowerofthewaveform3.Effectofsystemnoiseonthereceivedinformation4.Costofthesystem1.1Introduction81.2DigitalandAn

4、alogsourceandsystemThegenerationofcommunicationsystem9signalprocessorInanalogsystemitmaybeananaloglow-passfilter;Inhybridone,itmaybeanalog-to-digitalconverter(ADC)2)Functionofsignal-processingblockinhybridoneSourcecodingChannelcoding(addingparityandothers)3

5、)FunctionofCarrierCircuitsmodulationFunctionoftransmitter101）Classification:wireandwirelessWirechannelincludingtwisted-pairtelephoneline/Coaxialcables,waveguidesandfiber-opticcablesWirelesschannelhavingair,vacuumandseawater2)Note:Thegeneralprinciplesofdigit

6、alandanalogmodulationapplytoalltypesofchannels,althoughchannelcharacteristicsmayimposeconstraintsthatfavoraparticulartypeofsignalingChannel11Thereceivertakesthecorruptedsignalatthechanneloutputandconvertsittoabasebandsignalthatcanbehandledbythereceiverbaseb

7、andprocessor,andthenthereceiverbasebandprocessorestimatethesourceinformationandoutputtheestimationresultReceiver12Thegoalistodesigncommunicationsystemthattransmitinformationtothereceiverwithaslittledeteriorationaspossiblewhilesatisfyingdesignconstrainssucha

8、sallowabletransmittedenergy,allowablesignalbandwidthandcost.Indigitalsystemmeasureofdeteriorationistakentobebiterrorrate(BER),whileinanalogsystemtheperformancemeasureisusuallytakentobethesignal-to-nois