短时傅立叶变换matlab仿真程序Word下载.docx

短时傅立叶变换matlab仿真程序Word下载.docx

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fN=8000;

n=10000;

t=0:

1/fN:

（n-1）/fN;

Generatesignals<

sig1=sin（2*pi*500*t）;

sig2=sin（2*pi*1000*t）/2;

puls=zeros（size（t））;

puls（2100）=10;

puls（2132）=10;

x=sig1+sig2+puls;

windowwidth<

win1=12.8*fN/1000;

%12.8ms102.4points

win2=6.4*fN/1000;

%6.4ms51.2points

win3=3.2*fN/1000;

%3.2ms25.6points

steppinglength<

stepping1=16;

stepping2=32;

stepping3=64;

nfftpoints<

nfft=min（256,length（x））;

painting（TimeFrequencyAnalysis）<

%----->

1.Hammingwindows,differentwindowwidth<

-----------

figure

（1）

subplot（311）;

specgram（x,nfft,fN,hanning（round（win3）））;

xlabel（'

time（ms）'

）

ylabel（'

frequency（kHz）'

title（'

STFTTime-FrequencyMap,Hammingwindows,windowwidth3.2ms'

subplot（312）;

specgram（x,nfft,fN,hanning（round（win2）））;

STFTTime-FrequencyMap,Hammingwindows,windowwidth6.4ms'

subplot（313）;

specgram（x,nfft,fN,hanning（round（win1）））;

STFTTime-FrequencyMap,Hammingwindows,windowwidth12.8ms'

%-------------------------------------

2.Gausswindow,differentwindowwidth<

figure

（2）

specgram（x,nfft,fN,gausswin（round（win3）））;

STFTTime-FrequencyMap,Gausswindow,windowwidth3.2ms'

specgram（x,nfft,fN,gausswin（round（win2）））;

STFTTime-FrequencyMap,Gausswindow,windowwidth6.4ms'

specgram（x,nfft,fN,gausswin（round（win1）））;

STFTTime-FrequencyMap,Gausswindow,windowwidth12.8ms'

%---------------------------------------

%------>

3.Hammingwindows,differentsteppinglength<

figure（3）

specgram（x,nfft,fN,hanning（round（win1））,stepping1）;

STFTTime-FrequencyMap,Hammingwindows,windowwidth12.8ms,steppinglength16'

specgram（x,nfft,fN,hanning（round（win1））,stepping2）;

STFTTime-FrequencyMap,Hammingwindows,steppinglength32'

specgram（x,nfft,fN,hanning（round（win1））,stepping3）;

STFTTime-FrequencyMap,Hammingwindows,windowwidth12.8ms,steppinglength64'

4.Gausswindow,differentsteppinglength<

figure（4）

specgram（x,nfft,fN,gausswin（round（win1））,16）;

STFTTime-FrequencyMap,Gausswindow,windowwidth12.8ms,steppinglength16'

specgram（x,nfft,fN,gausswin（round（win1））,32）;

STFTTime-FrequencyMap,Gausswindow,windowwidth12.8ms,steppinglength32'

specgram（x,nfft,fN,gausswin（round（win1））,64）;

STFTTime-FrequencyMap,Gausswindow,windowwidth12.8ms,steppinglength64'