|Title||Performance comparisons of frequency-difference and conventional beamforming|
|Publication Type||Journal Article|
|Year of Publication||2017|
|Authors||Douglass A.S, Song HC, Dowling D.R|
|Journal||Journal of the Acoustical Society of America|
|Type of Article||Article|
|Keywords||blind deconvolution; source localization|
Frequency-difference beamforming [ Abadi, Song, and Dowling (2012b). J. Acoust. Soc. Am. 132, 3018-3029] is an unconventional beamforming method for use with sparse receiver arrays. It involves beamforming a quadratic product of complex field amplitudes, P(omega(2))P*(omega(1)), at the difference frequency, omega(2)-omega(1), instead of beamforming the complex field amplitude P(omega) at frequencies omega within the signal bandwidth. Frequency-difference beamforming is readily implemented with ordinary transducer array recordings of non-zero bandwidth signals. Results for, and comparisons of, frequency-difference beamforming from simulations and experiments are reported herein. In particular, spherical-wave beamforming is investigated using 15 and 165 kHz pulse signals in a 1.07-m-diameter water tank with a linear array having 14 elements spaced 5.08 cm apart. Here, frequency-difference beamforming using the high-frequency pulses provides comparable results to conventional beamforming at 15 kHz. Plane-wave beamforming is investigated using 11.232.8 kHz frequency-sweep signals broadcast 3 km through a 106-m-deep ocean sound channel to a vertical array having 16 elements spaced 3.75m apart. Here, frequency difference beamforming in the 1.7-2.3 kHz difference frequency band provides results comparable to conventional beamforming in this band. (C) 2017 Acoustical Society of America.