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

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.