program_9_3.m

《数字信号处理：基于计算机的方法（第三版）》资源下载第三部分。 著者： （美）米特拉著 作译者： 孙洪等译 ISBN号： 7-121-02652-X 出版日期： 2006-06 出版

% Program 9_3
% Design of IIR Butterworth Bandpass Filter
%
Wp = input('Passband edge frequencies = ');
Ws = input('Stopband edge frequencies = ');
Rp = input('Passband ripple in dB = ');
Rs = input('Minimum stopband attenuation = ');
[N,Wn] = buttord(Wp, Ws, Rp, Rs);
[b,a] = butter(N,Wn);
[h,omega] = freqz(b,a,256);
gain = 20*log10(abs(h));
plot (omega/pi,gain);grid;
xlabel('\omega/\pi'); ylabel('Gain, dB');
title('IIR Butterworth Bandpass Filter');