firhp.asv

滤波器的MATLAB实现程序 内附多个源代码

clc
clear all
close all
T1=0.1095;
T2=0.598;
N=61;
alpha=(N-1)/2;
l=0:N-1;wl=(2*pi/N)*l;
Hrs=[zeros(1,22),T1,T2,ones(1,14),T2,T1,zeros(1,21)];
Hdr=[0 0 1 1];
wdl=[0  0.75 0.75 1];
k1=0:floor((N-1)/2);k2=floor((N-1)/2)+1:N-1;
angH=[-alpha*(2*pi)/N*(k1),alpha*(2*pi)/N*(N-k2)];
Hdk=Hrs.*exp(j*angH);
h=real(ifft(Hdk,N));
[H,w]=freqz(h,[1],1000,'whole');
H=(H(1:501))';
w=(w(1:501))';
mag=abs(H);
db=20*log10((mag+eps)/max(mag));
pha=angle(H);
M=length(h);
L=(M-1)/2;
a=[h(L+1) 2*h(L:-1:1)];
n=[0:L];
ww=[0:500]'*pi/500;
Hr=sin(ww*n)*a';

figure
subplot(221);plot(wl/pi+1/N,Hrs,'.',wdl,Hdr);
axis([0 1 -0.1 1.1]);
title('Bandpass')
grid
subplot(222);stem(l,h,'k');grid;
title('impulse response')
subplot(223);plot(ww/pi,Hr,'k',wl/pi+1/N,Hrs,'.');
axis([0 1 -0.1 1.1]);
title('amplitude response')
grid
subplot(224);plot(w/pi,db,'k');
title('Magnitude response')
grid
axis([0 1 -100 10]);