FFT , IFFT and DSPlib

Started by Curl December 4, 2001
Hello ..
I'm not a C programmer, and i have little experience in this langage. I'd
like to ask a question to people who use the dsp library.

To perform an FFT followed by an Inverse FFT, I implement in assembly
language a "packing fft algorithm"
The input, x(n), is a 2N real sequence
Here are the steps for this algorithm :
1) Bit reverse
2) Complex FFT (on N points)
3) "unpacking" (N points complex spectrum -> 2N point complex spectrum )
At this point i have X(k) the spectrum of x(n)
4) "packing" (2N points complex spectrum -> N point complex spectrum )
5) Bit reverse
6) Complex IFFT (or conjugate+complex FFT+conjugate) on N points
At this point i'm back with x(n)

It works.. (I have still problems since it is 16 bits precision, but that's
not the point)

I'd like to do the same thing in C language..What are the steps in C :
1) cbrev and 2) rfft to get X(k) .. and then ??

Thank you...