sy33.m

来自「数字信号处理工具箱」· M 代码 · 共 22 行

N=33;alpha=(N-1)/2;k=0:N-1;wk=(2*pi/N)*k;
Hk=[ones(1,4),0.5,zeros(1,24),0.5,ones(1,3)];
angH=-alpha*(2*pi)/N*k;H=Hk.*exp(i*angH);
h=real(ifft(H,N));
[db,mag,pha,grd,w]=freqz_m(h,1);
[Hr,ww,a,L]=Hr_Type1(h);
subplot(2,2,1);
plot(ww/pi,Hr,wk(1:17)/pi,Hk(1:17),'o');
axis([0,1,-0.5,1.2]);
subplot(2,2,2);plot(w/pi,db);axis([0,1,-100,10]);grid
%过渡带设置2个采样点
N=34;alpha=(N-1)/2;k=0:N-1;wk=(2*pi/N)*k;
Hk=[ones(1,4),0.5925,0.1099,zeros(1,23),-0.1099,-0.5925,-ones(1,3)];
angH=-alpha*(2*pi)/N*k;H=Hk.*exp(i*angH);
h=real(ifft(H,N));
[db,mag,pha,grd,w]=freqz_m(h,1);
[Hr,ww,a,L]=Hr_Type2(h);
subplot(2,2,3);
plot(ww/pi,Hr,wk(1:17)/pi,Hk(1:17),'o');
axis([0,1,-0.5,1.2]);
subplot(2,2,4);plot(w/pi,db);axis([0,1,-100,10]);grid