Digital Filtering Techniques for Broadband Beamforming

Abstract : Digital steering of broadband hydrophone arrays is studied from the viewpoint of digital filtering theory. Emphasis is placed on applications wherein the sampling frequency must be kept as low as possible, implying that accurate beamforming involves interpolating the signals' samples. Finite- impulse-response filters are shown to provide convenient means for digital interpolation. Standard techniques for implementing such filters are reviewed and applied to the design of beamforming algorithms. Estimates are derived for the computing time and for the amount of core memory required by digital computer realizations of time-domain and frequency-domain beamforming processors.