ellip_lowpass.asv

设计了巴特沃斯、车比雪夫I

%设计椭圆低通滤波器
fs=360;%采样频率，the Nyquist frequency (180 Hz)
fn=fs/2;
Wp=50/fn;Ws=100/fn;%分别为通带截止频率和阻带截止频率
Rp=3;As=60; %通带最大衰减Rp=3 dB;
                                                %阻带最小衰减As=60
[n,Wn]=ellipord(Wp,Ws, Rp,As)   
[b, a]=ellip(n,Rp,Rs,Wn);                    %
%[num,den]=bilinear(b,a,1000); 
sztitle=sprintf('% d阶椭圆低通滤波器', n);
freq(b,a,sztitle);