%設計一個巴特沃思高通濾波器
fp=0.5;fs=0.1;
rp=3;rs=40;
Fs=250;
wp=2*pi*fp/Fs;
ws=2*pi*fs/Fs;
Fs=Fs/Fs; 
wap=tan(wp/2);
was=tan(ws/2);
[n,wn]=buttord(wap,was,rp,rs,'s');
[z,p,k]=buttap(n);
[b,a]=zp2tf(z,p,k);
[bt,at]=lp2hp(b,a,wap);
[bz,az]=bilinear(bt,at,Fs/2);
[hg,w]=freqz(bz,az,2048,Fs*2000);%高通濾波
%plot(w,abs(hg));

%設計一個巴特沃思低通濾波器
wp1=25*2*pi; 
ws1=16*2*pi; 
rp1=3; 
rs1=40; 
%fs=250; 
[n1,wn1]=buttord(wp1,ws1,rp1,rs1,'s') 
[z1,p1,k1]=buttap(n1); 
[b0,a0]=zp2tf(z1,p1,k1); 
[b1,a1]=lp2lp(b0,a0,wn1); 
[hd,wd]=freqs(b1,a1); 
%subplot(211) 
plot(wd/(2*pi),abs(hd));grid on;

y=load('D:\zhangyaohua\張要花的數據\右腳收縮壓3\you2.txt');
subplot(211);
plot(y);
grid;

%11點平均
e_out = eleven_avg(y);
% subplot(222)
% plot(e_out);
% grid;

%加載高通濾波器
N=length(e_out);
%size(e_out)
nfft=2048;
X1=fft(e_out,nfft)/2048;
XYG=X1.*abs(hg');
%size(X1)
%size(y)
xyg1=real(ifft(XYG));

%加載低通濾波器
X2=fft(xyg1,nfft)/2048;
XYG1=X2.*abs(hg');
xyg2=real(ifft(XYG1));

% 繪制高通后波形
% subplot(223);
% plot(xyg1*10^3);
% grid on ;

%繪制低通后波形
subplot(212);
plot(xyg2*10^6);
grid on ;