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.

Hi, I see a FFT functions in the Espressif DSP Library at :
https://docs.espressif.com/projects/esp-dsp/en/latest/esp-dsp-apis.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 ...