How the function "Bake sound to F-Curve" works?

Good evening.
I’m student and i write a diploma work about visualization music, that
can be create with Blender and scripts Python. So, I have the very important questions:
How the function “Bake sound to F-Curve” in a graph editor works ?
Is this the function use Fourier analysis (FFT, STFT) ?
Where I can find a code in Blender, which execute this function?