%program p311
wp=0.5*pi;
ws=0.66*pi;
width=ws-wp;%width of transition band
N=ceil(8*pi/width);%the length of the filter
if(rem(N,2))==0
    N=N+1;
end
Nw=N;%the length of the filter
wc=(wp+ws)/2;%cutoff freq.of the filter
n=0:N-1;
alpha=(N-1)/2;
m=n-alpha+0.00001;
hd=sin(wc*m)./(pi*m);
win=hanning(Nw);
h=hd.*win';
b=h;
freqz(b,1,512);