m=load('A.txt'); N=length(m); for i=1:N-1 ; q(i,1)=m(i,1); end; d=q'; s1=d; change=1000; [c,l] = wavedec(d,3,'db4'); %提取小波分解后的低频系数 ca3=appcoef(c,l,'db4',3); %提取各层小波分解后的高频系数 cd3=detcoef(c,l,3); cd2=detcoef(c,l,2); cd1=detcoef(c,l,1); %对信号强制消噪 cdd3=zeros(1,length(cd3));%第三层高频系数 cd3 全置 0 cdd2=zeros(1,length(cd2));%第二层高频系数 cd2 全置 0 cdd1=zeros(1,length(cd1));%第一层高频系数 cd1 全置 0 c1=[ca3,cdd3,cdd2,cdd1];%构建新的系数矩阵 s2=waverec(c1,l,'db4')%分解新的结构 %[thr,sorh,keepapp]=ddencmp('den','wv',d); %s2=wdencmp('gbl',c,l,'db4',4,thr,sorh,keepapp); %subplot(413) %plot(1:change,s2(1:change)); %title('默认软阈值消噪后信号') figure(1) subplot(9,2,1) plot(1:change,s1(1:change)) title('原始信号') ylabel('S1') subplot(9,2,2) plot(1:change,s2(1:change)) title('强制消噪后信号') ylabel('S2') 

wpt=wpdec(s1,3,'db1','shannon'); %plot(wpt); %重构第三层 8 个节点小波系数 s130=wprcoef(wpt,[3,0]); s131=wprcoef(wpt,[3,1]); s132=wprcoef(wpt,[3,2]); s133=wprcoef(wpt,[3,3]); s134=wprcoef(wpt,[3,4]); s135=wprcoef(wpt,[3,5]); s136=wprcoef(wpt,[3,6]); s137=wprcoef(wpt,[3,7]); %计算第三层 8 个节点小波能量 s10=norm(s130); s11=norm(s131); s12=norm(s132); s13=norm(s133); s14=norm(s134); s15=norm(s135); s16=norm(s136); s17=norm(s137); %计算方差 st10=std(s130); st11=std(s131); st12=std(s132); st13=std(s133); st14=std(s134); st15=std(s135); st16=std(s136); st17=std(s137); disp('正常信号的特征向量'); snorm1=[s10,s11,s12,s13,s14,s15,s16,s17]; std1=[st10,st11,st12,st13,st14,st15,st16,st17]; %显示三层个节点小波系数 subplot(9,2,3);plot(1:change,s130(1:change));ylabel('S130'); subplot(9,2,5);plot(1:change,s131(1:change));ylabel('S131'); subplot(9,2,7);plot(1:change,s132(1:change));ylabel('S132'); subplot(9,2,9);plot(1:change,s133(1:change));ylabel('S133'); subplot(9,2,11);plot(1:change,s134(1:change));ylabel('S134'); 

subplot(9,2,13);plot(1:change,s135(1:change));ylabel('S135'); subplot(9,2,15);plot(1:change,s136(1:change));ylabel('S136'); subplot(9,2,17);plot(1:change,s137(1:change));ylabel('S137');