%TCH/FS信道的外編碼
function u=T_FS_EX_EN(d)
%截短循環碼的外編碼
temp=zeros(1,53);
temp=d(1:50);
temp(51:53)=ones(1,3);
before=[0,0,0];
after=[0,0,0];
for i=1:53   %循環計算奇偶校驗位
   after(1)=mod(temp(i)+before(3),2);
   after(2)=mod(temp(i)+before(1)+before(3),2);
   after(3)=before(2);
   before=after;
end
p=after;  %得到三位校驗比特
%重排
u=zeros(1,189);
for k=0:90
    u(k+1)=d(2*k+1);
    u(185-k)=d(2*k+2);
end
u(92:94)=p(3:-1:1);
u(186:189)=zeros(1,4); %加尾比特
u(190:267)=d(183:260);