小波分析在matlab中实现的具体步骤
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发布时间：2022-04-30 00:42
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时间：2022-06-27 10:36
%利用db5小波对信号进行7层分解
%生产正弦信号
clc;close all;clear all;
N=1000;
t=1:N;
sig1=sin(0.3*t);
%生成三角形波形
sig2(1:500)=((1:500)-1)/500;
sig2(501:N)=(1000-(501:1000))/500;
figure(1);
subplot(211);
plot(t,sig1,'linewidth',2);
xlabel('样本序号 N');
ylabel('幅值A');
subplot(212);
plot(t,sig2,'linewidth',2);
xlabel('样本序号 N');
ylabel('幅值A');
%叠加信号
x=sig1+sig2+randn(1,N);
figure(2);
plot(t,x,'linewidth',2);
xlabel('样本序号 N');
ylabel('幅值A');%一维小波分解
[c,l]=wavedec(x,7,'db5');%重构第1-7层*近系数
a7=wrcoef('a',c,l,'db5',7);
a6=wrcoef('a',c,l,'db5',6);
a5=wrcoef('a',c,l,'db5',5);
a4=wrcoef('a',c,l,'db5',4);
a3=wrcoef('a',c,l,'db5',3);
a2=wrcoef('a',c,l,'db5',2);
a1=wrcoef('a',c,l,'db5',1);%显示*近系数
figure(3)
subplot(711)
plot(a7,'linewidth',2);
ylabel('a7');
subplot(712)
plot(a6,'linewidth',2);
ylabel('a6');
subplot(713)
plot(a5,'linewidth',2);
ylabel('a5');
subplot(714)
plot(a4,'linewidth',2);
ylabel('a4');
subplot(715)
plot(a3,'linewidth',2);
ylabel('a3');
subplot(716)
plot(a2,'linewidth',2);
ylabel('a2');
subplot(717)
plot(a1,'linewidth',2);
ylabel('a1');
xlabel('样本序号 N');%重构第1-7层细节系数
d7=wrcoef('d',c,l,'db5',7);
d6=wrcoef('d',c,l,'db5',6);
d5=wrcoef('d',c,l,'db5',5);
d4=wrcoef('d',c,l,'db5',4);
d3=wrcoef('d',c,l,'db5',3);
d2=wrcoef('d',c,l,'db5',2);
d1=wrcoef('d',c,l,'db5',1);
%显示细节系数
figure(4)
subplot(711)
plot(d7,'linewidth',2);
ylabel('d7');
subplot(712)
plot(d6,'linewidth',2);
ylabel('d6');
subplot(713)
plot(d5,'linewidth',2);
ylabel('d5');
subplot(714)
plot(d4,'linewidth',2);
ylabel('d4');
subplot(715)
plot(d3,'linewidth',2);
ylabel('d3');
subplot(716)
plot(d2,'linewidth',2);
ylabel('d2');
subplot(717)
plot(d1,'linewidth',2);
ylabel('d1');
xlabel('样本序号 N');
