ex0306.m

数字信号处理（机械工业出版社）的源码

b = [0.0181,  0.0543, 0.0543,  0.0181];
a = [1.0000, -1.7600, 1.1829, -0.2781];
K = 200; 
[H,w] = freqresp(b,a,K);
magH = abs(H); angH = angle(H);
subplot(2,1,1); plot(w/pi,magH); grid on; axis([0,1,0,1])
xlabel('frequency in pi units'); ylabel('|H|');
title('Magnitude Response');
subplot(2,1,2); plot(w/pi,angH/pi); grid on
xlabel('frequency in pi units'); ylabel('Phase in pi Radians');
title('Phase Response');