//Design of FIR Filter using Frquency Sampling Technique
//Low Pass Filter Design
//Cutoff Frequency Wc = pi/2
//M =  Filter Lenth = 7
clear;
clc;
M = 7;
N = ((M-1)/2)+1
wc = %pi/2;
for k =1:M
  w(k) = ((2*%pi)/M)*(k-1);
  if (w(k)>=wc)
    k-1
    break
  end
end
for i = 1:k-1
  Hr(i) = 1;
  G(i) = ((-1)^(i-1))*Hr(i);
end
for i = k:N
  Hr(i) = 0;
  G(i) = ((-1)^(i-1))*Hr(i);
end
h = zeros(1,M);
for n = 1:M
  for k = 2:N
    h(n) = G(k)*cos((2*%pi/M)*(k-1)*((n-1)+(1/2)))+h(n);
  end
 h(n) = (1/M)* (G(1)+2*h(n));
end
[hzm,fr]=frmag(h,256);
hzm_dB = 20*log10(hzm)./max(hzm);
plot(2*fr,hzm_dB)
xtitle('Frequency Response of LPF with Normalized cutoff =0.5','Normalized Frequency W ------>','Magnitude Response H(w)---->');
xgrid(1);