www.pudn.com > 现代信号处理教程.rar > exa080401.m

%----------------------------------------------------------------------------------- 
% exa080401.m    for example 8.4.1 and fig8.4.2 
% 说明一个三通道滤波器组的频率响应 
% h0(n),h1(n): 来自文献 [Ngu89] 
%----------------------------------------------------------------------------------- 
 
clear; 
 
           h= [-0.0429753          -0.0927704           0.0429888   
                 0.0000139           0.0000008          -0.0000139 
                 0.1489104           0.0087654          -0.1489217 
                 0.2971954           0.0000226           0.2972354 
                 0.3537539           0.1864025          -0.3537496 
                 0.2672266          -0.0000020           0.2672007 
                 0.0870758          -0.3543303          -0.0870508 
                -0.0521155          -0.0000363          -0.0520909 
                -0.0875973           0.3564594           0.0875786 
                -0.0427096          -0.0000049          -0.0427067 
                0.0474530          -0.1931082          -0.0474452 
                0.0429618           0.0000230           0.0429677 
                0.0                 0.0                 0.0 
               -0.0232765          -0.0000026          -0.0232749 
               0.0000022           0.0                 0.0000022]; 
            h0=h(:,1); 
            h1=h(:,2); 
            h2=h(:,3); 
 
[H0,w]=freqz(h0,1,512,1); 
[H1,w]=freqz(h1,1,512,1); 
[H2,w]=freqz(h2,1,512,1); 
H00=20*log10(abs(H0+0.0000001)); 
H11=20*log10(abs(H1+0.0000001)); 
H22=20*log10(abs(H2+0.0000001)); 
plot(w,H00,'b-',w,H11,'k-',w,H22,'r-'); 
 
grid on; 
title('H0                                    H1                                H2'); 
ylabel('                dB'); 
hold on;