Check out https://en.m.wikipedia.org/wiki/Short-time_Fourier_transform https://en.m.wikipedia.org/wiki/Short-time_Fourier_transform This is the "Fourier transf

Check out https://en.m.wikipedia.org/wiki/Short-time_Fourier_transform https://en.m.wikipedia.org/wiki/Short-time_Fourier_transform This is the "Fourier transform" that is most often used, in practice in computing. A longer window length gives lower frequency resolution, but longer latency.