OK, thanks, I will make a note in the javadocs.

----- Original Message ----
From: alkottke <alkottke@...>
To: jsci@yahoogroups.com
Sent: Friday, 25 August, 2006 5:23:42 PM
Subject: [jsci] Re: inverse Fourier Transform

Turns out it is easy to create a transfer function using the other
notation, just use the conjugate.

--- In jsci@yahoogroups.com, "alkottke" <alkottke@...> wrote:
>
> Hello,
>
> So I found out the issue. Matlab uses -2pi in the transform and 2pi
> in the inverse, whereas JSci uses 2pi in the transform and -2pi in the
> inverse transform. If I recall correctly, the difference between +/-
> 2pi is a matter of convention, but I don't know how to create a
> transfer function in the frequency domain when the -2pi convention is
> applied. Mathworld also uses the -2pi transform, 2pi inverse
> convention: http://mathworld.wolfram.com/FourierTransform.html
>
> --- In jsci@yahoogroups.com, Mark Hale <mj_hale@> wrote:
> >
> > Hi,
> >
> > As the data is increasing positive, increasing negative then you
> don't need the first initial sort, ie inverseTransform(data), if you
> want the output in sequential time order, then you need the last sort,
> ie sort(inverseTransform(data)).
> >
> > If you still have problems, send me some test data and a screen
> shot of the results in matlab.
> >
> > Regards,
> >
> > Mark
> >
> >
> > ----- Original Message ----
> > From: alkottke <alkottke@>
> > To: jsci@yahoogroups.com
> > Sent: Thursday, 24 August, 2006 8:22:58 PM
> > Subject: [jsci] inverse Fourier Transform
> >
> > I had some problems getting the inverse Fourier Transform to work. I
> > have a Fourier Amplitude Spectrum (FAS) that with increasing positive
> > frequencies, the Nyquist frequency, and the increasing negative
> > frequencies. I tried using sort(inverseTransform(sort(...))) to
> > compute the time history, but the results don't make any sense. I
> > also tried with and without the both of the sort() commands. Which is
> > appropriate?
> >
> > Right now I decided to use another FFT library because the results
> > that it produces match the results I compute using matlab. However, I
> > would like to use JSci to simplify the libraries.
> >
> > Can anyone explain to me how to properly use inverseTransform()?
> >
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
>







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