FFT - iFFT

[kheber]

Hi, I see a FFT functions in the Espressif DSP Library at :
https://docs.espressif.com/projects/esp ... s.html#fft

However, it is unclear which functions are forward or backward FFT / iFFT. The documentation is very unhelpful and there are no examples given.

Can anyone provide application examples of FFT / iFFT?

Thank you

[tommeyers]

Where have you looked? What did you find? (Google.com ?)

Tom

[bobolink]

For complex numbers you can use the FFT for the IFT:
ift = conjugate, fft, conjugate, scale
Check a math book for details.

[kheber]

That's an idea; thank you. It requires unanticipated work and it should be in ASM to be fully optimized. Most other DSP suppliers have already solved that problem and written a proper iFFT for their libraries.