FIG. F-11. f,k plot. (a) The region passed by array, frequency, and velocity filters is cross-hatched. Radial lines through the origin represent constant apparent velocity Va (Va=f/k=ω/κ). (b) Data beyond the Nyquist wavenumber fN (determined by discrete spatial sampling) wraps around (aliases) and may get mixed up with the signal. In wraparound, data to the right of +kN continues rightward from –kN, where KN is the Nyquist wavenumber.