c713.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

%bandstop Filter


Wp=[60 260];Ws=[100 150];Gp=-2.2;Gs=-20;

% Butterworth


[N,Wn]=buttord(Wp,Ws,-Gp,-Gs,'s')
[num,den]=butter(N,Wn,'stop','s')

% Cheby1

%[N,Wn]=cheb1ord(Wp,Ws,-Gp,-Gs,'s');
%[num,den]=cheby1(N,-Gp,Wn,'stop','s')

% Cheby2

%[N,Wn]=cheb2ord(Wp,Ws,-Gp,-Gs,'s');
%[num,den]=cheby2(N,-Gs,Wn,'stop','s')


% Elliptic

%[N,Wn]=ellipord(Wp,Ws,-Gp,-Gs,'s');
%[num,den]=ellip(N,-Gp,-Gs,Wn,'stop','s')



w=0:1:1000; w=w';
[mag,phase,w]=bode(num,den,w);
plot(w,mag)