![](https://csdnimg.cn/release/download_crawler_static/22826256/bg7.jpg)
f=(0:length(Xn1)-1)*f/length(Xn1);w=f*2*pi;
H=freqs(b,a,w);
%高通滤波器
function [H,f]=keshegaotonglvboqi(wp,ws,Rp,As,Xn1)
T=0.001;
fs=1/T;
[N,Wc]=buttord(wp,ws,Rp,As,'s');
[b,a]=butter(N,Wc,'high','s');
f=(0:length(Xn1)-1)*fs/length(Xn1);w=f*2*pi;
H=freqs(b,a,w);
%带阻滤波器
function [H,f]=keshedaizulvboqi(wp,ws,p,s,Xn1)
T=0.001;
f=1/T;
[N,Wc]=buttord(wp,ws,p,s,'s');
[b,a]=butter(N,Wc,'stop','s');
f=(0:length(Xn1)-1)*f/length(Xn1);w=f*2*pi;