in fact I didn't learn that
i'm still learning many things in a very short time and i was told to
make an FFT... then I found the FFT function on VisualDSP++, called
dit and it worked ;)
Mark Borgerding <mark@borgerding.net> wrote in message news:<UslGc.186055$DG4.167479@fe2.columbus.rr.com>...
> Luis Fernando wrote:
> > Hello
> >
> > FFT can convert a given number of samples from time domain to
> > frequency domain.
> > Ok... what about the inverse?
> >
> > Basically I'd like to have something like that:
> >
> > input -> FFT -> "something" -> output
> > with input = output
>
>
> You are describing an inverse FFT.
> ifft( fft( x ) ) == x
>
> The mathematics are almost exactly the same as the forward FFT.
>
> I'm curious. How did you learn about the FFT without being exposed to
> the inverse FFT?
>
>
> -- Mark
Reply by Luis Fernando●July 6, 20042004-07-06
yes
of course that's a test ;)
spam@dspdimension.com (Stephan M. Bernsee) wrote in message news:<42c34ef.0407052023.24174d2a@posting.google.com>...
> Well, the FFT is invertible - just use the iFFT. But since in your
> application input = output, there is probably no reason to use it at
> all...?
>
> --smb
Reply by Stephan M. Bernsee●July 6, 20042004-07-06
Well, the FFT is invertible - just use the iFFT. But since in your
application input = output, there is probably no reason to use it at
all...?
--smb
wavebox@wavebox.com.br (Luis Fernando) wrote in message news:<fb78d2e7.0407051418.72ae4004@posting.google.com>...
> Hello
>
> FFT can convert a given number of samples from time domain to
> frequency domain.
> Ok... what about the inverse?
>
> Basically I'd like to have something like that:
>
> input -> FFT -> "something" -> output
> with input = output
>
> I think I could do that generating sinusoides on the
> frequency/amplitude given by FFT and summing them, but it probably
> will be very slow
>
> Any ideas?
>
> thanks
Reply by Luis Fernando●July 6, 20042004-07-06
now I found something called IFT that probably do what I asked ;)
trying to work with it...
Reply by Mark Borgerding●July 5, 20042004-07-05
Luis Fernando wrote:
> Hello
>
> FFT can convert a given number of samples from time domain to
> frequency domain.
> Ok... what about the inverse?
>
> Basically I'd like to have something like that:
>
> input -> FFT -> "something" -> output
> with input = output
You are describing an inverse FFT.
ifft( fft( x ) ) == x
The mathematics are almost exactly the same as the forward FFT.
I'm curious. How did you learn about the FFT without being exposed to
the inverse FFT?
-- Mark
Reply by Luis Fernando●July 5, 20042004-07-05
Hello
FFT can convert a given number of samples from time domain to
frequency domain.
Ok... what about the inverse?
Basically I'd like to have something like that:
input -> FFT -> "something" -> output
with input = output
I think I could do that generating sinusoides on the
frequency/amplitude given by FFT and summing them, but it probably
will be very slow
Any ideas?
thanks