function?[ts]?=?inverse_st（st）?
%?Returns?the?inverse?of?the?Stockwell?Transform?of?the?REAL_VALUED?timeseries.?
%?Code?by?Robert?Glenn?Stockwell.?
%?Reference?is?“Localization?of?the?Complex?Spectrum:?The?S?Transform“?
%?from?IEEE?Transactions?on?Signal?Processing?vol.?44.?number?4?April?1996?pages?998-1001.?
%?
%-------Inputs?Needed------------------------------------------------?
%???
%??S-Transform?matrix?created?by?the?st.m?function?
%-------Optional?Inputs?------------------------------------------------?
%?none?
%-------Outputs?Returned------------------------------------------------?
%?
%?ts?????-a?REAL-VALUED?time?series?
%--------Additional?details-----------------------?
%???Copyright?（c）?by?Bob?Stockwell?
%???$Revision:?1.0?$??$Date:?2004/10/10??$?
?
%?sum?over?time?to?create?the?FFT?spectrum?for?the?positive?frequencies?
stspe?=?sum（st2）;?
?
%?get?st?matrix?dimensions??
[nfreqntimes]?=?size（st）;?
if?rem（ntimes?2）?~=?0?
????%?odd?number?of?points?so?nyquist?point?is?not?aliased?so?concatenate?
????%?the?reversed?spectrum?to?create?the?negative?frequencies?
????%?drop?the?DC?value?
????negspe?=?fliplr（stspe（2:nfreq）‘）;?
else?
?????%?even?number?of?points?
?????%?therefore?drop?the?first?point?（DC）?and?the?last?point?（aliased?nyqusit?freq）?
?????negspe?=?fliplr（stspe（2:nfreq-1）‘）;?
end?
?
%?using?symmetry?of?FFT?spectrum?of?a?real?signal?recreate?the?negative?frequencies?from?the?positie?frequencies?
?fullstspe?=?[conj（stspe‘）??negspe];?????
?
%?the?time?series?is?the?inverse?fft?of?this?
ts?=?ifft（fullstspe）;?
%?and?take?the?real?part?the?imaginary?part?will?be?zero.?
ts?=?real（ts）;?
?

?屬性????????????大小?????日期????時間???名稱
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?????文件??????14070??2009-09-28?15:36??st.m

?????文件???????1677??2009-09-28?15:35??inverse_st.m

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