clear all
close all;
load ecgdata.txt;
y=ecgdata(:,1);
n=(0:0.004:1000)';

y=y(1:1:1000);
n=n(1:1:1000);
subplot(3,1,1)
%subplot(2,4,1)
plot(n,y);
title('心電信號(hào)')

wn=0.3;
N=3;
[b,a]=butter(N,wn,'low');
m=filter(b,a,y);
subplot(3,1,2)
%subplot(2,4,2)
plot(n,m);
title('巴特沃思濾波');

[c,l]=wavedec(m,2,'rbio6.8');
a4=wrcoef('a',c,l,'rbio6.8',2);
subplot(3,1,3)
%subplot(2,4,3)
plot(n,a4);
title('小波濾波');