-周期图法的功率谱估计

MatlabMatlabMatlabxnx0x1…xn-110)()(NnnjjNenxeX2102)(1)(1)(ˆNnnjjNenxNeXNP1Matlabt=0:0.001:0.6y=sin2*pi*50*t+sin2*pi*120*tx=y+randnsizetN=lengthx%nfft=1024%Xk=fftxnfftPxx=absXk.^2/Nindex=0roundnfft/2-1k=index*N/nfft%Hzplot_Pxx=10*log10Pxxindex+1%dBplotkplot_Pxxxlabel'Hz'ylabel'dB'title''gridonM.S.NxnLMLiMnnjimenxMLP120)(1ˆ2Matlab%t=0:0.001:0.6y=sin2*pi*50*t+sin2*pi*120*tx=y+randnsizetN=lengthx%n=1:1:N%Fs=1000%nfft=512%window=boxcar30noverlap=0p=0.9%psd[Pxx]=psdxnfftFswindownoverlappindex=0roundnfft/2-1k=index*Fs/nfftplot_Pxx=10*log10Pxxindex+1%dBplotkplot_Pxxxlabel'Hz'ylabel'dB'title''gridonP.O.LiMnnjimenxMULP120)(1ˆnnU)(ωn3WelchMatlab%t=0:0.001:0.6y=sin2*pi*50*t+sin2*pi*120*tx=y+randnsizetN=lengthx%n=1:1:N%Fs=1000%100nfft=512%%window=hamming25window=boxcar100noverlap=20range='half'%psd[Pxxf]=pwelchxwindownoverlapnfftFsrangeplot_Pxx=10*log10Pxx%dBplotfplot_Pxxxlabel'Hz'ylabel'dB'title'welch'gridon4Matlab%t=0:0.001:0.6y=sin2*pi*50*t+sin2*pi*120*tx=y+randnsizetN=lengthx%n=1:1:N%Fs=1000%100nfft=512%%window=hamming25window=boxcar100noverlap=20range='half'%psdnw=3.5p=0.99[PxxPxxcf]=pmtmxnwnfftFspplot_Pxx=10*log10Pxx%dBplotfplot_Pxxxlabel'Hz'ylabel'dB'title''gridon8[9]“”“”“”[1].[M].:,2005[2][]·.[J].,1988,(9)[3].[J].,2012,(4)[4].[J].,2009,(29)[5].[J].,2008,(1)[6].[J].,2012,(1)[7].[J].,2011,(36)[8].[J].,2012,(1)[9].[J].,2005,(9)[]2WelchWelch[1].[M].:,2002[2],.MATLAB[M].:,2004[3],.MATLAB6[J].,2005,10(3):1-5[4],.[J].,2005,(3)[]1965—PowerspectrumEstimationBasedonPeriodogramHUANGYing(SuzhouInstituteofTrade&Commerce,Suzhou,Jiangsu215009,China)Abstract:Spectralestimationisanimportantpartofdigitalsignalprocessing.Thispaperstudiedthebasicperioddiagrammethod,andrealizedsomeimprovedmethodsonMatlab.Keywords:SpectralEstimation;Periodogram;Matlab