% 2-D FIR filter design using fwind2
Hd = zeros(21,21);
Hd(:,8:14) = 1;
Hd(8:14,:) = 1;
colormap(gray);
imagesc(Hd);
figure();
h = fwind2(Hd, ones(21,21));
freqz2(h);
figure();
surf(h);