Band-pass Filter

Use the Band-pass option to apply a Fast-Fourier Transform Band Pass filter to a channel.

The filter option is available with the following extensions and menus:

  • Geophysics: 1D FFT > 1D Filtering
  • Gravity and Terrain Correction: Moving Platform Gravity  > Apply Single FFT Filter

Band-pass filter options

Short wavelength cutoff
(in ground units)

Short Wavelength cutoff value.(in ground units) (Default is 0.1).

Script Parameter: FFTBANDP.SHORTW

Long cutoff ->
Enter 0 for infinite value

Long Wavelength cutoff value. Enter 0 to have an Infinite cutoff wavelength.(in ground units) (Default is 1).

Script Parameter: FFTBANDP.LONGW

Pass or Reject Defined Band

Select "Pass" or "Reject" the defined band (default is Pass).

Script Parameter: FFTBANDP.PASS

Application Notes

This filter can be used to pass or reject a range of wavenumbers from the data. However, applying such a simple cutoff filter to an energy spectrum almost invariably introduces a significant amount of ringing (otherwise known as Gibb's Phenomena). We recommend that you use a smoother filter such as the Butterworth filter.

Band-pass Filter

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Parameters:

k0 Low wavenumber cutoff in cycles/ground_unit.

k1 High wavenumber cutoff in cycles/ground_unit.

0/1 If 1, pass the defined band. Otherwise, reject the defined band. The default is to pass the band.