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:1002-6886(2005)05-0001-03matlab(,130022):(1982),,2004,,:2005-4-12:MATLAB,,,MATLAB,wigner2ville:wigner2villematlabApplicationandStudyofMatlabonTime2frequencyAnalysisofSignalDAIHuan2yaoAbstract:ThesoftwareofMATLABhasgotextensiveapplicationinseveralresearchesrealm.Amongthem,itsfrequencychartanalysisanddesignfunctionofthefilterwiththeanalysisisverystrong,makearithmeticdigitalsignalhandledtobecomeverybrief,intuitionistic.Thistextintroducedtime2frequencyanalysisfoundationtheoriesandsomeapplied,makeuseoftheMATLABlanguagetoconstructakindoftimeandfrequencydensityfunction,aimsatexplainingsignalcontainingfrequencyweightanditsevolvecharacteristicbywigner2villedistribute.Keywords:time2frequencyanalysis;wigner2villedistribute;matlab;analyticssignal1,,,,,,,WD,WDchirp,,,(),,WD,MATLABMATLABSimu2link,,22.1STFT[8],,,,,,,,,,,,,,,,,,,,(1):STFTx(n,w)=m=-x(m)w(n-w)e-jwm(1):w(n),;x(n),n,n,n,(n,w)2.2:WD(WignerDistribution)f(t)WD:Wf(t,w)=f(t+2)f3(t-2)e-jwtd()(2)WDx(,t)=12-m=+X(+2)X3(-2)ejtd()(3),f(t)s(t),-+WVD,,(Cross-terms)(Artifacts)WD:,WD;1,WD,,,3STFTWD3.1STFTMATLAB::x(t)=ejkt2,:k=6,0T5,:fc=kT=30,fS=4fc,N=TfS=600,,STFTWD,:k=4;T=5;fc=k3T;fs=43fc;Ts=1/fs;N=T/Ts;x=zeros(1,N);t=0:N-1;x=exp(j3k3pi3(t3Ts).^2);subplot(2,2,1);plot(t3Ts,real(x));X=fft(x);X=fftshift(X);subplot(2,2,2);plot((t-N/2)3fs/N,abs(X));Nw=20;L=Nw/2;Tn=(N-Nw)/L+1;nfft=32;TF=zeros(Tn,nfft);fori=1:Tnxw=x((i-1)310+1:i310+10);temp=fft(xw,nfft);temp=fftshift(temp);TF(i,:)=temp;endsubplot(2,2,3);fnew=((1:nfft)-nfft/2)3fs/nfft;tnew=(1:Tn)3L3Ts;[F,T]=meshgrid(fnew,tnew);mesh(F,T,abs(TF));subplot(2,2,4);contour(F,T,abs(TF));x(t)=2cos(jkt2),k=4,0T5,:fc=kT=30,fS=4fcN=TfS=400,,,,,,,,,,,3.2WDMATLABwigner-villex(t)=exp(jkt2),:k=6,0T4;:fc=kT=24;:fS=4fc;N=TfS=384,,WD,k=6,,fcFFT,,fS=2fc,,WD,,fS=4fc,,220055,,WD4[7],,Wigner(STFT)Wigner,,,,,Wigner,,STFTWigner,,,(spectrogram,STFT)WignerSTFT,,-,WignerSTFT,STFT,,LFM,,,,x1(t),x1(t):f1(t)f2(t),1(t)2(t),A1A2,A2A1,x(t):x(t)=x1(t)+x2(t)=A1exp[j21(t)]+A2exp[j22()][5]=A1cos[21(t)]+jA1sin[21(t)]+A2cos[22(t)]+jA2sin[21(t)](4)={A1cos[21(t)]+A2cos[22(t)]}+j{A1sin[21(t)]+A2sin[22(t)]}x(t)f(t):f(t)=ddttan-1A1cos[21(t)]+A2cos[22(t)]A1sin[21(t)]+A2sin[22(t)]=ddttan-1A1A2cos[21(t)]+cos[22(t)]A1A2sin[21(t)]+sin[22(t)](5)A2A1,A1A20,:f(t)ddttan-1cos[22(t)]sin[21(t)]f2(t)(6),,,,4,,,-,,-;,,Wigner,,,,,1..1998,13,2,,.Wigner.,200143,,..,1997(1)4,,..,2001(1)5,,..2000(4)6,..,200327,..19976Vol.19No.38,,..20029..,199410..,20013