c126.m

matlab例程MATLAB 6.x版的内建数据类型（Built-in data type）就有5种以上

Wp=0.15;Ws=0.1;Gp=-1;Gs=-6.3;T=pi/100;

% Digital Highpass Butterworth

%[n,Wn]=buttord(Wp,Ws,-Gp,-Gs);
%[b,a]=butter(n,Wn,'high')

% Digital Highpass Cheby1

%[n,Wn]=cheb1ord(Wp,Ws,-Gp,-Gs);
%[b,a]=cheby1(n,-Gp,Wn,'high')


% Digital Highpass Cheby2


[n,Wn]=cheb2ord(Wp,Ws,-Gp,-Gs);
[b,a]=cheby2(n,-Gs,Wn,'high')


% Digital Highpass Elliptic

%[n,Wn]=ellipord(Wp,Ws,-Gp,-Gs);
%[b,a]=ellip(n,-Gp,-Gs,Wn,'high')




W=0:.01:pi;W=W';
T=pi/100;
 W=0:.01:pi;W=W';
          H=freqz(b,a,W);
          w=W/T;
          mag=abs(H);
          phase=180/pi*unwrap(angle(H));
          subplot(2,1,1);
          plot(w,mag);grid;
          subplot(2,1,2);
          plot(w,phase);grid