matlab 小波去噪程序

load jzxh.txt

s1=jzxh;


fs=500000;  %采样频率
t=1:max(size(s1));
t=1000*t./fs;
t=t';
plot(s1),title('plot(s1)'),grid on;
%axis([0,51.2,-10000,10000]);
xlabel('时间（t）   单位：ms');
ylabel('电压（V)');
title('原始信号');

%小波分解
[c,l]=wavedec(s1,4,'sym6');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1 2 3 4]);
ca4=appcoef(c,l,'sym6',4);
a4=wrcoef('a',c,l,'sym6',4);
d4=wrcoef('d',c,l,'sym6',4);
d3=wrcoef('d',c,l,'sym6',3);
d2=wrcoef('d',c,l,'sym6',2);
d1=wrcoef('d',c,l,'sym6',1);
%不需要的系数置零
caa4=zeros(size(ca4));

%消噪后信号重构，并画图
cl=[caa4,cd4,cd3,cd2,cd1]