Bandpass (BPAS)

Use the Bandpass option to apply a bandpass filter.

Bandpass Filter dialog options

Long wavelength cutoff	The long wavelength cutoff in ground unit. See illustration, this parameter is equivalent to k0-1.
Short wavelength cutoff	The short wavelength cutoff in ground unit. See illustration, this parameter is equivalent to k1-1.
Pass Reject	Pass or reject the defined band; The default is to pass the band.

Application Notes

The bandpass filter (BPAS) can be used to pass or reject a range of wavelengths contained in the data. However, applying such a simple cutoff filter operator to an energy spectrum almost invariably introduces a significant amount of oscillation (also known as Gibbs’ Phenomenon). This filter is present for the sake of completeness. We recommend that you use a tapered filter such as the Butterworth filter (BTWR).

Bandpass Filter

Where:

k0	Low wavenumber cutoff in cycles/ ground unit.
k1	High wavenumber cutoff in cycles/ground unit.

Wavenumber domain variable definition

k	Wavenumber domain increment, used to depict a radially symmetrical variable.	where: np is the number of points cs is the cell size
u	X component in the wavenumber domain.	k = 2π ( i μ+j ν )
v	Y component in the wavenumber domain.
r	Radial component in the wavenumber domain.	also 2πk
θ	Polar component in the wavenumber domain.

Ground_unit is the survey ground units as defined in your grid (e.g. metre or feet). Ground units may be left undefined.