% 第四章: 例4.11:
%   z-平面函數:
% a)
b = [1,0]; a = [1, -0.9];
pzplotz(b,a); title('極點-零點圖');
text(0.85,-0.1,'0.9');text(0.01,-0.1,'0');pause,
print -deps fg0407.eps
% b)
[H,w]=freqz(b,a,100);
magH = abs(H);phaH = angle(H);
subplot(2,1,1),plot(w/pi,magH);grid
xlabel('');ylabel('幅度');
title('幅度響應')
subplot(2,1,2);plot(w/pi,phaH/pi);grid
xlabel('頻率 (單位:pi)');ylabel('相位 (單位:pi)');
title('相位響應'),
print -deps fg0408.eps
subplot