examp16_11.m

《小波分析理论与Matlab7实现例程》一书里面各章节的源码

clf;
clear;
%调入含突变点的信号
load nearbrk;
x=nearbrk;
N=length(x);
t=1:N;
figure(1);
plot(t,x,'LineWidth',2);xlabel('时间 t/s');ylabel('幅值 A');
%一维小波分解
[c,l] = wavedec(x,5,'db2');
%重构第5层逼近系数
a5 = wrcoef('a',c,l,'db2',5);
%重构第1～5层细节系数
d5 = wrcoef('d',c,l,'db2',5);
d4 = wrcoef('d',c,l,'db2',4);
d3 = wrcoef('d',c,l,'db2',3);
d2 = wrcoef('d',c,l,'db2',2);
d1 = wrcoef('d',c,l,'db2',1);
%显示重构系数和细节系数
figure(2)
subplot(6,1,1);plot(d5,'LineWidth',2);ylabel('d5');
subplot(6,1,2);plot(d4,'LineWidth',2);ylabel('d4');
subplot(6,1,3);plot(d3,'LineWidth',2);ylabel('d3');
subplot(6,1,4);plot(d2,'LineWidth',2);ylabel('d2');
subplot(6,1,5);plot(d1,'LineWidth',2);ylabel('d1');
subplot(6,1,6);plot(a5,'LineWidth',2);ylabel('a5');
xlabel('时间 t/s');