dframe_head.m

定义了通信中帧格式

function y = dframe_head(x,data_length,k,error_num)

backer_code(2,:) = [1 1 0 0 0 0 0 0 0 0 0 0 0];
backer_code(3,:) = [1 1 0 0 0 0 0 0 0 0 0 0 0];
backer_code(4,:) = [1 1 1 0 0 0 0 0 0 0 0 0 0];
backer_code(5,:) = [1 1 1 0 1 0 0 0 0 0 0 0 0];
backer_code(7,:) = [1 1 1 0 0 1 0 0 0 0 0 0 0];
backer_code(11,:) = [1 1 1 0 0 0 1 0 0 1 0 0 0];
backer_code(13,:) = [1 1 1 1 1 0 0 1 1 0 1 0 1];
temp_code = backer_code(k,1:k);
if sum(temp_code) == 0
   error('Input the Wrong Length of the Backer code')
end
framehead = [temp_code ~temp_code temp_code];
s = length(framehead);
m = length(x);
kk = 0;
if rem(m,data_length+s) > 0
    n=rem(m,data_length+s);
    x=[x,zeros(size(1:(data_length+s)-rem(m,data_length+s)))];
end
for i=1:(m-s+1)
    temp_flag = 0;
    temp_flag = xor(framehead,x(i:i+s-1));
    if sum(temp_flag) <= error_num        
        y(1+kk*data_length:data_length+kk*data_length) = x(i+s:i+s+data_length-1);
        kk=kk+1;
    end
end
compli = data_length+s-n;
y = y(1:(end-compli));