文档介绍：实验五基于MATLAB的IIRDF设计I一、实验目的练****并掌握脉冲响应不变法设计IIR数字滤波器的方法;练****并掌握双线性变换法设计IIR数字滤波器的方法;,、数字低通/高通/带通/带阻的幅频和相频特性图。低通指标:wp=,rp=ldB,ws=,rs=16dBo高通指标:wp=,rp=ldB,ws=,rs=30dBo带通指标:wp=],rp=ldB,ws=[],rs=30dBo带阻指标:wp=[],rp=ldB,ws=[],rs=30dBo低通:»Wp=*pi;Ws=*pi;Rp=l;Rs=16;Fs=1000;%数字滤波器指标%模拟滤波器设计wp=Wp*Fs;ws=Ws*Fs;Rp=7;Rs=16;%模拟滤波器指标:w=QT->Q=w*Fs[n,Wn]=buttord(wp,ws,Rp,Rs,'s');%阶次估计[z,p,k]=buttap(n);%模拟低通原型[b,a]=zp2tf(z,p,k);%零极点・>直接[b,a]=lp2lp(b,a,Wn);%低通・>低通(去归一化)[H,w]=freqs(b,a);figure(1)subplot(2,l,1),plot(w/2/pi,20*log10(abs(H)));gridxlabel(*Frequence(Hz)'),ylabel('Magnitude(dB)');subplot(2,1,2),plot(w/2/pi,angle(H)/pi*180);gridxlabel(*Frequence(Hz)'),ylabel('Phase(degress)');%冲激响应不变法设计数字滤波器figure(2)[bz,az]=impinvar(b,a,Fs);freqz(bz,az,256);%数字滤波器的直接设计figure(3)[n,wn]=buttord(Wp/pi,Ws/piRp,Rs)[b,al=butter(n,wn);freqz(b,a,256);n=3wn=*[LIh)二:me f=?mm -imenf=*r*aq■■cca<1刁》mnmeime•imeg-iuew(ss异p)aJd'2OOoo-50-1OO- 03 04 (xnrad/sample) 1-3OOoO-1OO-200O102 03 04 07 06NormalizedFrequency(xtirad/sample)09■6Oo-20- «ilizedFrequency(xtir^d/scirripie)-1OO-200O (xitrad/sampI高通:»wp=*pi;ws=*pi;rp=l;rs=30;Fs=2000;%Firstlytofinishfrequencyprewarping;