hammingfir.m

用MATLAB实现FIR滤波器

clear all;
N=10;
b1=fir1(N,0.25,boxcar(N+1));
b2=fir1(N,0.25,hamming(N+1));
M=128;
h1=freqz(b1,1,M);
h2=freqz(b2,1,M);
t=0:10;
subplot(2,2,1)
stem(t,b2,'.');hold on;
plot(t,zeros(1,11));grid;
f=0:0.5/M:0.5-0.5/M;
M1=M/4;
for k=1:M1
    hd(k)=1;
    hd(k+M1)=0;
    hd(k+2*M1)=0;
    hd(k+3*M1)=0;
end
subplot(2,2,2)
plot(f,abs(h1),'b-',f,abs(h2),'g-',f,hd,'-');grid;