In soapy power manual:

Crop: -o PERCENT, --overlap PERCENT percent of overlap when frequency hopping (incompatible with -k) -k PERCENT, --crop PERCENT percent of crop when frequency hopping (incompatible with -o)

I know the overlap,what means crop in FFT calculation?

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1 Answer 1


"to crop" means "to cut off at the end".

In the case of this program (which is a bit obscure), it is just used in one place, psd.result's source code:

    if self._crop_factor:
        crop_bins_half = round((self._crop_factor * self._bins) / 2)
        freq_array = freq_array[crop_bins_half:-crop_bins_half]
        pwr_array = pwr_array[crop_bins_half:-crop_bins_half]

So, instead of the full calculated PSD you just get a "cropped" version, centered around the middle.

  • $\begingroup$ Thanks for your answer.What's the scenario to use crop instead of overlap? $\endgroup$
    – kittygirl
    Mar 13, 2022 at 11:15
  • $\begingroup$ Can't tell you. I'd never use it. $\endgroup$ Mar 13, 2022 at 12:02

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