香农编码 ·例：有一单符号离散无记忆信源 X X2 X3 X4 X5 0.40.30.20.050.05 。X1(00) X1(00) X2(01) x2(01) X3(101) X3(10) 。X4(11100) ·X4(110) X5(11101) X5(111) H(X)1.95 7= =78% H(X)1.95 2.5 7= =92.9% 2.1 11 • 例: 有一单符号离散无记忆信源 1 2 3 4 5 ( ) 0.4 0.3 0.2 0.05 0.05 X x x x x x p x              香农编码 x1 (00) x2 (01) x3 (101) x4 (11100) x5 (11101) ( ) 1.95 78% 2.5 H X K     ( ) 1.95 92.9% 2.1 H X K     x1 (00) x2 (01) x5 (111) x3 (10) x4 (110)