High-pass Filter

Use the High-pass option to apply a Fast-Fourier Transform High-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

Wavelength cutoff
(in ground units)

Wavelength cutoff value (in ground units) Enter 0 for an infinitely long wavelength (Default is 0).

Script Parameter: FFTHIGHP.WAVEL

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k₀ The cutoff wavenumber in cycles/ground_unit. All wavenumbers above this value are removed.

Ground_unit is the survey ground units used in your grid (eg. metre, feet etc.).

As with the band-pass filter, the low-pass filter is seldom used because the results usually suffer from Gibb's Phenomena (ringing).