function?[TFSP]?=?STFT（DMfm）;

%?y:?input?signal????????????????????????????????輸入信號
%?D:?the?data?matrix:?D（:1）=t;?D（:2）=y;????
%?M:?the?lenght?of?the?FT?window?????????????????窗口長度
%?[0?fm]?The?Frequency?range?for?the?signal??????信號頻率范圍
%?SP:?the?spectogram?（short?time?fourier?transform）?of?D???D的短時傅里葉變換

%fm?%?the?maximum?freq?

t=D（:1）;y=D（:2）;
N=length（y）;

W=hanning（M）;
ye=zeros（N+M1）;
ye（M/2+1:M/2+N）=y;
%yea=hilbert（ye）;
dt=t（2）-t（1）;%?time?resolution
fs=1/dt;?%?the?sampling?frequency

df=fs/M;?%frequency?resolution
L=round（fm/df）;?%?the?index?of?the?max?freq.
f=[0:L-1]*df;

i=1;
while?i<=N
???
???s=ye（i:i+M-1）.*W;
??%?sa=hilbert（s）;
???
???S=fft（s）;
???B（:i）=S（1:L）;
???i=i+1;%?increase?by?one?（next?sample）
end

SP?=?（1/N）*abs（B.*B）;
SP?=?SP/max（max（SP））;?%?normalize?it
T??=?t;
F??=?f;



%?mesh（TFSP）
%?contour（TFSP）

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件????3911703??2011-08-19?15:33??STFT\I.mat

?????文件????1408454??2011-08-19?15:33??STFT\Q.mat

?????文件????????924??2011-09-15?11:17??STFT\STFT.m

?????文件????????870??2011-09-15?11:17??STFT\Test.m

?????文件????????506??2012-08-01?15:40??STFT\Test.rar

?????文件????????524??2011-09-16?19:52??STFT\Untitled.m

?????目錄??????????0??2012-08-01?15:40??STFT

-----------?---------??----------?-----??----

??????????????5322981????????????????????7