CODEWITHSUNDEEP
signal-processingfft
Rad'Val
Rad'Val

Reputation: 9231

Estimate the fundamental frequency using cepstral analysis

Wrote a frequency domain pitch detection algorithm in C and now I'm trying to estimate the fundamental frequency. I have the maximum magnitude bin from the Fourier Transform, but that can also be an harmonic not necessary F0. I read somewhere that it is possible to estimate F0 using cepstral analysis. So, here are the steps I follow:

  1. Take time domain buffer x, make a windowed copy w.
  2. FTTw = FFT(w)
  3. a = Log of square magnitude of FTTw
  4. FTTa = FFT(a)
  5. b = square magnitude of FTTa
  6. Estimate fundamental using b

I'm having trouble with the last step (6). The magnitudes in b are pretty high and I'm not sure I fully understand what they represent (quefrencies?) and most of all how can I estimate the fundamental based on them.

Any advice is welcome! Thanks!

Upvotes: 1

Views: 2416

Answers (1)

Paul R
Paul R

Reputation: 212979

The location of the peak in the cepstrum (on the quefrency axis) tells you the pitch period of your original signal. The magnitude of the peak is not particularly important.

Upvotes: 1

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