卷积码matlab程序

卷积编码程序：

function [output, len_tal] = cnv_encd(secrettext, encodetext)

g = [0 0 1 0 0 1 0 0; 0 0 0 0 0 0 0 1; 1 0 0 0 0 0 0 1; 0 1 0 0 1 1 0 1]; k0 = 1;

% 读入文本文件并计算文件长度

frr = fopen(secrettext, 'r');

[msg, len] = fread(frr, 'ubit1');

msg = msg';

% check to see if extra zero padding is necessary

if rem(length(msg), k0) > 0

msg = [msg, zeros(size(1:k0-rem(length(msg),k0)))];

end

n = length(msg)/k0; % 把输入比特按k0分组，n为所得的组数。

% check the size of matrix g

if rem(size(g, 2), k0) > 0

error('Error, g is not of the right size.');

end

% determine L and n0

L = size(g, 2)/k0;

n0 = size(g, 1);

% add extra zeros，以保证编码器是从全0开始，并回到全0状态。

u = [zeros(size(1:(L-1)*k0)), msg, zeros(size(1:(L-1)*k0))];

% generate uu, a matrix whose columns are the contents of conv. encoder at

% various clock cycles.

u1 = u(L*k0: -1 :1);

for i = 1:n+L-2

u1 = [u1, u((i+L)*k0:-1:i*k0+1)];

end

uu = reshape(u1, L*k0, n+L-1);

% determine the output

output = reshape(rem(g*uu, 2), 1, n0*(L+n-1));

len_tal = n0*(L + n - 1);

% write the output to the encodetext result = fopen(encodetext, 'w');

for i = 1:n0*(L+n -1)

fwrite(result, output(i), 'bit1'); end

fclose(result);