function output=training_ds(train_l,input)
%該程序將輸入序列擴頻后在其前面加入了訓練序列
%train_l: the length of training series
%pn     :  pn code
%input  : information data
input=2*input-1;
if train_l<=0
   error('Error,train_l is not of the right size.')
end
if length(input)~=1*5
   %error('Error,length of input is not of the right size.')
end
pn=[1 1 1 1 1 -1 -1 1 1 -1 1 -1 1];

xt=[1 -1];

if rem(train_l,2)>0
   temp=xt'*ones(1,train_l/2-1);
   training=reshape(temp,1,train_l-1);
   training=[training,1];
else
   temp=xt'*ones(1,train_l/2);
   training=reshape(temp,1,train_l);
end


temp=pn'*input;
data=reshape(temp,1,length(input)*length(pn));
output=[training,data];