On Jun 28, 5:18*pm, "BobW" <nimby_GIMME_SOME_S...@roadrunner.com>
wrote:
> I'm using a microcontroller (dsPIC30F3013) to do an FFT on some "real" data
> (from a microphone) and I don't have enough internal RAM to get the
> frequency resolution I need.
>
> I found a forum entry by Rick Lyons as follows:
>
> -quote-
> Does the dsPIC33 allow you to perform
> 512-point FFT on complex-valued input
> samples? *If so, there's a way to perform
> a 1024-point *real-input* FFT using
> a 512-point complex FFT routine.
> [-Rick-]
> -end quote-
>
> The FFT routine I have available does take a complex input (two sixteen bit
> words), and the existing code merely stuffs zeroes into the imaginary part
> of each complex input.
>
> So, can anyone tell me what the trick is for allowing this complex-input FFT
> to be more efficient with real input data such that I can effectively cutin
> half the input record length I need to use.
>
> Thanks in advance.
>
> Bob
> --
> == All google group posts are automatically deleted due to spam ==

Google is your friend. Try searching on 'real FFT' - the 3rd entry for
me is this which seems useful:

http://www.engineeringproductivityto...T0001/PT10.HTM

Eric