www.gusucode.com > MATLAB仿真技术与应用__的配套例题和习题的matlab源代码 > 第四章/example9.m

    %MATLAB program 4-9
% 10-order Analog filter design
clear all;
clc;
N=10; Rp=3; Rs=60;
[z,p,k]=ellipap(N,Rp,Rs);               %设计模拟原型低通滤波器
[A,B,C,D]=zp2ss(z,p,k);            
[At,Bt,Ct,Dt]=lp2lp(A,B,C,D,6*pi);       %模拟原型低通滤波器
%转换成所需的低通滤波
[b,a]=ss2tf(At,Bt,Ct,Dt);
figure;
[h,w]=freqs(b,a); 
mag = 20*log10(abs(h));
plot(w,mag);
grid;
[At1,Bt1,Ct1,Dt1]=lp2lp(A,B,C,D,40*pi);       %模拟原型低通滤波器
%转换成所需的高通滤波
[b1,a1]=ss2tf(At1,Bt1,Ct1,Dt1);
figure;
[h1,w1]=freqs(b1,a1); 
mag1 = 20*log10(abs(h1));
plot(w1,mag1);
grid;