% Chapter 07: Example 7.12 Differentiator design - Hamming window % M = 21; alpha = (M-1)/2; n = 0:M-1; hd = (cos(pi*(n-alpha)))./(n-alpha); hd(alpha+1)=0; w_ham = (hamming(M))'; h = hd .* w_ham; [Hr,w,P,L] = Hr_Type3(h); % plots subplot(1,1,1); subplot(2,2,1); stem(n,hd); title('Ideal Impulse Response') axis([-1 M -1.2 1.2]); xlabel('n'); ylabel('hd(n)') subplot(2,2,2); stem(n,w_ham);title('Hamming Window') axis([-1 M 0 1.2]); xlabel('n'); ylabel('w(n)') subplot(2,2,3); stem(n,h);title('Actual Impulse Response') axis([-1 M -1.2 1.2]); xlabel('n'); ylabel('h(n)') subplot(2,2,4);plot(w/pi,Hr/pi); title('Amplitude Response');grid; xlabel('frequency in pi units'); ylabel('slope in pi units') axis([0 1 0 1]); set(gca,'XTickMode','manual','XTick',[0,0.2,0.4,0.6,0.8,1]) set(gca,'YTickMode','manual','YTick',[0,0.2,0.4,0.6,0.8,1])
