《数字信号处理》-张旭 IIR数字滤波器的设计

wp=2*fp/fs;Рwst=2*fst/fs;Рrp=3;Рas=35;Р[N,wn]=cheb1ord(wp,wst,rp,as);Р[b,a]=cheby1(N,rp,wn,'high');Р[h,w]=freqz(b,a,256);Рsubplot(321);plot(w/pi,abs(h));title('滤波器幅频响应');Рsubplot(322);plot(w/pi,angle(h));title('滤波器相频响应');Рf1=10;f2=300;Рt=[1:256];Рx=cos(2*pi*f1*t/fs)+sin(2*pi*f2*t/fs);РX=fft(x);Рsubplot(323);plot(abs(X));title('原函数幅频响应');Рsubplot(324);plot(angle(X));title('原函数相频响应');РH=X.*h';Рsubplot(325);plot(abs(H));title('处理后函数幅频响应');Рsubplot(326);plot(angle(H));title('处理后函数相频响应');Р6.3 实验3程序Рf1=100;Рf2=200;Рf3=400;Рf4=500;Рfs=5000;Рrp=3;Рwst1=2*f1/fs;Рwp1=2*f2/fs;Рwp2=2*f3/fs;Рwst2=2*f4/fs;Рws=[wst1,wst2];Рwp=[wp1,wp2];Рas=40;Р[N1,wn]=buttord(wp,ws,rp,as);Р[b,a]=butter(N1,wn);Р[h1,w1]=freqz(b,a,256);Рas=20;Р[N2,wn]=buttord(wp,ws,rp,as);Р[b,a]=butter(N2,wn);Р[h2,w2]=freqz(b,a,256);Рas=30;