According to the FOURIER THEOREM, periodic sound may be shown to consist of SINE WAVEs in the HARMONIC SERIES, where the Fourier coefficients give the AMPLITUDE and PHASE angle of each component.

He’s using a Fast Fourier Transform routine crafted in C ... with just a bit of noticeable lag between the sound and the waveform representation on the graphic LCD. We found his notes about ...

Thus after identifying maxima they zoom in and perform a Fourier transform to spot the wideband burst. It’s all done in Python, and the pleasant surprise is how straightforward to understand it ...