_信息论之父Shannon的经典之作:《通信的数学理论》.pdf

_信息论之父Shannon的经典之作:《通信的数学理论》.pdf

ID:50220958

大小:982.97 KB

页数:55页

时间:2020-03-12

_信息论之父Shannon的经典之作:《通信的数学理论》.pdf_第1页
_信息论之父Shannon的经典之作:《通信的数学理论》.pdf_第2页
_信息论之父Shannon的经典之作:《通信的数学理论》.pdf_第3页
_信息论之父Shannon的经典之作:《通信的数学理论》.pdf_第4页
_信息论之父Shannon的经典之作:《通信的数学理论》.pdf_第5页
资源描述:

《_信息论之父Shannon的经典之作:《通信的数学理论》.pdf》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库

1、ReprintedwithcorrectionsfromTheBellSystemTechnicalJournal,Vol.27,pp.379–423,623–656,July,October,1948.AMathematicalTheoryofCommunicationByC.E.SHANNONINTRODUCTIONHErecentdevelopmentofvariousmethodsofmodulationsuchasPCMandPPMwhichexchangebandwidthforsignal-to-noiser

2、atiohasintensifiedtheinterestinageneraltheoryofcommunication.ATbasisforsuchatheoryiscontainedintheimportantpapersofNyquist1andHartley2onthissubject.Inthepresentpaperwewillextendthetheorytoincludeanumberofnewfactors,inparticulartheeffectofnoiseinthechannel,andthesav

3、ingspossibleduetothestatisticalstructureoftheoriginalmessageandduetothenatureofthefinaldestinationoftheinformation.Thefundamentalproblemofcommunicationisthatofreproducingatonepointeitherexactlyorap-proximatelyamessageselectedatanotherpoint.Frequentlythemessageshave

4、meaning;thatistheyrefertoorarecorrelatedaccordingtosomesystemwithcertainphysicalorconceptualentities.Thesesemanticaspectsofcommunicationareirrelevanttotheengineeringproblem.Thesignificantaspectisthattheactualmessageisoneselectedfromasetofpossiblemessages.Thesystemm

5、ustbedesignedtooperateforeachpossibleselection,notjusttheonewhichwillactuallybechosensincethisisunknownatthetimeofdesign.Ifthenumberofmessagesinthesetisfinitethenthisnumberoranymonotonicfunctionofthisnumbercanberegardedasameasureoftheinformationproducedwhenonemessa

6、geischosenfromtheset,allchoicesbeingequallylikely.AswaspointedoutbyHartleythemostnaturalchoiceisthelogarithmicfunction.Althoughthisdefinitionmustbegeneralizedconsiderablywhenweconsidertheinfluenceofthestatisticsofthemessageandwhenwehaveacontinuousrangeofmessages,wew

7、illinallcasesuseanessentiallylogarithmicmeasure.Thelogarithmicmeasureismoreconvenientforvariousreasons:1.Itispracticallymoreuseful.Parametersofengineeringimportancesuchastime,bandwidth,numberofrelays,etc.,tendtovarylinearlywiththelogarithmofthenumberofpossibilitie

8、s.Forexample,addingonerelaytoagroupdoublesthenumberofpossiblestatesoftherelays.Itadds1tothebase2logarithmofthisnumber.Doublingthetimeroughlysquaresthenu

当前文档最多预览五页,下载文档查看全文

此文档下载收益归作者所有

当前文档最多预览五页,下载文档查看全文
温馨提示:
1. 部分包含数学公式或PPT动画的文件,查看预览时可能会显示错乱或异常,文件下载后无此问题,请放心下载。
2. 本文档由用户上传,版权归属用户,天天文库负责整理代发布。如果您对本文档版权有争议请及时联系客服。
3. 下载前请仔细阅读文档内容,确认文档内容符合您的需求后进行下载,若出现内容与标题不符可向本站投诉处理。
4. 下载文档时可能由于网络波动等原因无法下载或下载错误,付费完成后未能成功下载的用户请联系客服处理。