通信原理第3讲 信源编码：信息论部分ppt课件

1、12, () ,( ,) inX P XxXx xx1212,( )(),(),()ninXxxxP xP xP xP x( , )( )( )Xxa bp xp x1lLXXXX1XlLXXX1lLxxxx1121321121( )()() (|) (|)(|)LLLP xP xxP x P xx P xx xP xxx x1212,( ),(),()( )LLnLnaaaXP aP aP aP x11231( )()( ) () ()()( )LlLLiiP xP xxxP x P x P xP xP x1lnmmmmaaaa( )iI P x()( )( )iiH XE I P xE I

2、 P1()( )loglog( )( )iiiiI P XxI P xP xP x 11( )()logloglog( )log()( )()iiiiiiI P xI P yP xP yP xP y 1( )loglog( )( )1()loglog()()1(|)loglog(|)(|)1(|)loglog(|)(|)1()loglog()()iiiiiiiiiiiiiiiiiiiiiiiiI P xP xP xI P yP yP yI P xyP xyP xyI P yxP yxP yxI P x yP x yP x y 1()( )( )log( )niiiiH XE I P xP xP

3、 x 10.6930.301 bitNatDetmax()logHXn12()()()nP xP xP x1( ) () log()()log()mjjjjjH YE I P yEP yP yP y 11(|) (|) log(|)()log(|)nmjijiijjiijH Y XE I P yxEP yxP x yP yx 11(|) (|) log(|)()log(|)nmijijijijijH X YE I P xyEP xyP x yP xy 11(, ) () log()()log()nmijijijijijH X YE I P x yEP x yP x yP x y (, )()(

4、|)( )(|)H X YH XH Y XH YH X Y()(|)( )(|)H XH X YH YH Y X12121321121()(,)()(|)(|,)(|,)LLLH XH XXXH XH XXH XXXH XXXX121()(,)LLHXH XXXL12121020()lim(|,)()()()logLLLHXH XXXXHXH XHXN121()lim(|,)LLLHXH XXXX0()()HXHX0()()HXHX0()11()HXRHX (; )()(|)log( )log(|)log( )log(|)( )log( ;)(|)()(; )( )(|)log(;)(|)ii

5、iiiiiiiiiiiiiiI X YH XH X YEP xEP xyEP xP xyP xEE i x yP xyP yI X YH YH Y XEE i y xP yx(, )()(|)( )(|)H X YH XH Y XH YH X YLKnmLKnmLKnmloglogLKKnnmLm11()loglognHXnnn ()()HXH X22log()log()loglogKnKH XKmH XLmLmL2logKmL2logKRmL2()logRK Lm2()logKH XLm22()1()loglogH XKH XmLLm22()1()1()()log 2log 2H XKH X

6、KH XH XLLLLK L0, ( ,), 1,2, , 1,2,0, ijijijijxyd x ydinjmxy1111( ,) ( ,)( ) (|) ( ,)nmijijijnmijiijijdP x y d x yP x P yx d x yDd11(|):( ) (|) ( ,)nmDjiijiijijPP yxDdP x P yx d x y(|)jiP yx111111(; )()log()( ) (|)log(|)(|)( ) (|)log( ) (|)( ); (|)mnmjjijijijijnmjiijimijijijijiI X YP yP yP x P yxP yxP yxP x P yxP x P yxI P xP yx (|) P()min( ); (|)jiDijiP y xR DI P xP yx12sHTf( )sTt( )()sTskttkT1( )()sTsksffkfT2sHff( )( )( )() ()ssTsskx tx ttx kTtkT( )( )( )1( )()1()ssfskssksXfX ffX ffkfTX fkfT2sHff1,2( )0, H