function aa=a_mid_1()
w=4; M=1;p=128;
lm=p+w-1;


amid1(1:128,1)=midamble_1;

for i=1:M
   amid(1:128,i)=amid1(1:128,i);
   amid(129:lm,i)=0;
end;

for i=1:w-1
   for j=i*M+1:(i+1)*M
      amid(1:i,j)=0;
      if j==(i+1)*M
         amid(i+1:p+i,j)=amid1(1:128,M);
      else 
         amid(i+1:p+i,j)=amid1(1:128,mod(j,i*M));
      end;
      
      if i~=w-1
         amid(p+i+1:lm,j)=0;
      end;
      
   end;
   
end;
aa=amid;