clear Fs=1000, n=0:1/Fs:I; xn=cos(2*pi*40*n)+3*cos(2*pi*100*n)+randn(size(n)): n=1024: window=boxcar(100),%矩形窗 window1-hamming((100,%海明窗 window2-blackma ckman窗 noverlap=20,%数据无重叠 range-halP,%频率间隔为0Fs/2,只计算一半的频率 [Pxx.f]-pwelch(xn.window.noverlap.nffi.Fs.range). plot_Pxx=10*log10(Pxx): plot Pxx1=10*log10(Pxx1): plot_Pxx2=l0*logl0(Pxx2) figure(1) plot(fplot_Pxx)方 pause figure(2) plot(fplot Pxx1): pause. figure(3) plot(fplot_Pxx2):clear; Fs=1000; n=0:1/Fs:1; xn=cos(2*pi*40*n)+3*cos(2*pi*100*n)+randn(size(n)); nfft=1024; window=boxcar(100); %矩形窗 window1=hamming(100); %海明窗 window2=blackman(100); %blackman 窗 noverlap=20; %数据无重叠 range='half'; %频率间隔为[0 Fs/2]，只计算一半的频率 [Pxx,f]=pwelch(xn,window,noverlap,nfft,Fs,range); [Pxx1,f]=pwelch(xn,window1,noverlap,nfft,Fs,range); [Pxx2,f]=pwelch(xn,window2,noverlap,nfft,Fs,range); plot_Pxx=10*log10(Pxx); plot_Pxx1=10*log10(Pxx1); plot_Pxx2=10*log10(Pxx2); figure(1) plot(f,plot_Pxx); pause; figure(2) plot(f,plot_Pxx1); pause; figure(3) plot(f,plot_Pxx2);