%采樣頻率
fs=10000;
%軸承外環(huán)故障信號(hào)
fid=fopen('bearingout.dat','r');%故障
N=1024;
xdata=fread(fid,N,'int16');
fclose(fid);
xdata=(xdata-mean(xdata))/std(xdata,1);

%時(shí)域波形
figure(1);
plot(1:N,xdata);
xlabel('時(shí)間 t/n');
ylabel('電壓 V/v');

%db10小波進(jìn)行4層分解
%一維小波分解
[c,l] = wavedec(xdata,4,'db10');

%重構(gòu)第1～4層細(xì)節(jié)信號(hào)
d4 = wrcoef('d',c,l,'db10',4);
d3 = wrcoef('d',c,l,'db10',3);
d2 = wrcoef('d',c,l,'db10',2);
d1 = wrcoef('d',c,l,'db10',1);

%顯示細(xì)節(jié)信號(hào)
figure(2)
subplot(4,1,1);
plot(d4,'LineWidth',2);
ylabel('d4');
subplot(4,1,2);
plot(d3,'LineWidth',2);
ylabel('d3');
subplot(4,1,3);
plot(d2,'LineWidth',2);
ylabel('d2');
subplot(4,1,4);
plot(d1,'LineWidth',2);
ylabel('d1');
xlabel('時(shí)間 t/s');

%第1層細(xì)節(jié)信號(hào)的包絡(luò)譜
y=hilbert(d1);
ydata=abs(y);
y=y-mean(y);
nfft=1024;
p=abs(fft(ydata,nfft));
figure(3);
plot((0:nfft/2-1)/nfft*fs,p(1:nfft/2));
xlabel('頻率 f/Hz');
ylabel('功率譜 P/W');