实验7clearall;wp1=0.2*pi;ws1=0.3*pi;Rp=1;Rs=10;Fs=1;wp2=2*Fs*tan(wp1/2);ws2=2*Fs*tan(ws1/2);[N,Wn]=buttord(wp2,ws2,Rp,Rs,'s');[Z,P,K]=buttap(N);[Bap,Aap]=zp2tf(Z,P,K);[b,a]=lp2lp(Bap,Aap,Wn);[bz,az]=bilinear(b,a,Fs);[H,W]=freqz(bz,az,64);subplot(2,1,1);plot(W/pi,abs(H));xlabel('ƵÂÊ');ylabel(&