Reply by robert bristow-johnson●February 24, 20092009-02-24
On Feb 22, 11:00�pm, "m26k9" <maduranga.liyan...@gmail.com> wrote:
> Sorry for bumping..anybody?
well, if i could more clearly understand what you're question is
about, i might try to answer.
r b-j
Reply by m26k9●February 23, 20092009-02-23
Sorry for bumping..anybody?
Reply by m26k9●February 19, 20092009-02-19
Hello,
I am in academia so my knowledge on FFT are limited to what I find in
basic DSP books. I have a question on scalable FFT. This is mainly regarded
to OFDMA where they supports different bin numbers, ranging from 128 to
2048.
Now my question is how this is implemented in a FFT hardware module. I
think different methods must be using by different manufactureres. But I am
interested in a standard/general approach.
For example, if I want to do a 4-point FFT on a 8-point FFT module, is the
output taken from the first stage, instead of the 2nd stage for the 8-point
case? I am considering a raidx-2 butterfly structure. The case is more
complicated when you have to support from 128~2048 range.
Specifically, I would like to know:
1) Are the twiddle factors changed dynamically to the required FFT
points?
2) If so are they usually stored in some memory and read in?
3) OR am I getting the whole scalable FFT thing wrongly?
Thank you.