cepstrum

Wikipedia article: https://en.wikipedia.org/wiki/Cepstrum

• Mangling of the word "spectrum"
• Computing it consists of 3 steps:
  • transform signal from time domain into frequency domain (FFT)
  • take logarithm of the spectrum yielded by FFT
  • transformation to [quefrency] domain

"Sometimes called the "spectrum of a spectrum""

"The cepstrum can be seen as information about the rate of change in the different spectrum bands"

• Wikipedia article

^ These are very helpful for understanding this thing.

Ah, I see. This is like derivatives and higher-order functions. We're lifting things up and operating on them in these higher/more abstract representations and then converting them back.