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1、5.1 设信源(1) 求信源熵H(X)；(2) 编二进制香农码；(3) 计算平均码长和编码效率。解：(1)(2)可用matlab函数dec2bin(a,n) a-小数，n长度xip(xi)pa(xi)ki码字x10.203000x20.190.23001x30.180.393011x40.170.573100x50.150.743101x60.10.8941110x70.010.99711111101)0.0 - 0.0000002)0.2*2 = 0.4 00.4*2 = 0.8 00.8*2 = 1.6 13)0.39 * 2 = 0.78 00.78 * 2 = 1.56 10.56 *
2、 2 = 1.12 14)0.99 * 2 = 1.98 10.98 * 2 = 1.96 10.96 * 2 = 1.92 10.92 * 2 = 1.84 10.84 * 2 = 1.68 10.68 * 2 = 1.36 10.36 * 2 = 0.72 0(3)5.2 对信源编二进制费诺码，计算编码效率。解：xip(xi)编码码字kix10.200002x20.19100103x30.1810113x40.1710102x50.15101103x60.11011104x70.011111145.3 对信源编二进制和三进制哈夫曼码，计算各自的平均码长和编码效率。解：二进制哈夫曼码：xip
3、(xi)编码码字kis61s50.610s40.391s30.350s20.261x10.20102x20.191112x30.1800003x40.1710013x50.1500103s10.111x60.1001104x70.01101114三进制哈夫曼码：xip(xi)编码码字kis31s20.540s10.261x10.2221x20.190002x30.181012x40.172022x50.150102x60.11112x70.0121225.4 设信源(1) 求信源熵H(X)；(2) 编二进制香农码和二进制费诺码；(3) 计算二进制香农码和二进制费诺码的平均码长和编码效率；(4)
4、 编三进制费诺码；(5) 计算三进制费诺码的平均码长和编码效率；解：(1)(2)二进制香农码：xip(xi)pa(xi)ki码字x10.5010x20.250.5210x30.1250.753110x40.06250.87541110x50.031250.9375511110x60.0156250.968756111110x70.00781250.98437571111110x80.00781250.992187571111111二进制费诺码：xip(xi)编码码字kix10.5001x20.2510102x30.125101103x40.06251011104x50.0312510111105x60.015625101111106x70.00781251011111107x80.0078125111111117(3)香农编码效率：费诺编码效率：(4)xip(xi)编码码字kix10.5001x20.25111x30.12520202x40.06251212x50.03125202203x60.01562512213x70.00781252022204x80.0078125122214(5)
