I have a PDM data input from the MEMS microphone on the Pynq-Z1 development board. My eventual goal is to take the FFT of the audio samples and display the frequency bins on some LED.
I am struggling to understand what exactly is needed to convert the PDM signal to an acceptable input for the FFT. I have seen some videos explaining converting the PDM to PCM by applying a low pass FIR and then decimating the sampling rate.
Is this needed for my hobby project? Can I just average the PDM samples ( 0 to 1 ) over chunks of time T, to give a really simple idea of the amplitude at that time, and then feed these samples to the FFT?
How much do I need to process my PDM? I am very weak in the area of DSP.
Any help much appreciated.