Does anyone have a clue as to why -using mscohere- the coherence becomes exactly one for all frequencies if nfft is set to about 190-200. I know it's standard practice to set it to a number that is a power of 2. I tried with 1024, and all I got was a bunch of NaN. So I started with low numbers, and the coherence seem to have plausible numbers until I hit the 190 mark. I'm completely baffled. Looking forward to hearing from you.

  • $\begingroup$ how many input points? $\endgroup$ – Stanley Pawlukiewicz Apr 18 at 11:57
  • $\begingroup$ I'm experimenting with 120 data points $\endgroup$ – Fede C Apr 18 at 12:40
  • $\begingroup$ you should have hundreds of points per bin. $\endgroup$ – Stanley Pawlukiewicz Apr 18 at 12:43
  • $\begingroup$ it's funny how they don't write that in the textbooks. In other words, you're saying whatever result I get (when I get numerical results) is rubbish? $\endgroup$ – Fede C Apr 18 at 12:58
  • $\begingroup$ I forgot to mention, I bootstrap the series, precisely because the sample size is very small. I suppose that doesn't change things? $\endgroup$ – Fede C Apr 18 at 12:59

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