Results 131 to 140 of about 1,058 (187)
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The Journal of the Acoustical Society of America, 1989
A cylindrical array employs rectangular planar array segments which extend in the axial direction when assembled on a cylindrical conducting plate having flat longitudinal portions to which the planar array segments are attached. Each planar array segment comprises two columns of planar transducer elements with each column extending in the axial ...
Stanley L. Ehrlich, George G. Gray
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A cylindrical array employs rectangular planar array segments which extend in the axial direction when assembled on a cylindrical conducting plate having flat longitudinal portions to which the planar array segments are attached. Each planar array segment comprises two columns of planar transducer elements with each column extending in the axial ...
Stanley L. Ehrlich, George G. Gray
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Sonar array signal processing for sparse linear arrays
ISSPA '99. Proceedings of the Fifth International Symposium on Signal Processing and its Applications (IEEE Cat. No.99EX359), 2003Acoustic signals which propagate through the ocean have wavefronts which can differ significantly from the "planar wavefronts" assumed in array signal processing. In this paper we investigate the performance of the the minimum variance distortionless response (MVDR) beamformer and the previously introduced Fourier integral method (FIM), when applied to
I. S. D. Solomon +2 more
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A novel beamformer for circular sonar arrays
ICASSP '81. IEEE International Conference on Acoustics, Speech, and Signal Processing, 2005A new Beamformer (BF) technique using Linear Deltamodulation (DM) on the spatially sampled circular array sensor signals is presented. In this method, the FIR-type of beam-former implementation for circular arrays results in an extremely simplified hardware which does away with multipliers and retains basically adders.
Rajendar Bahl, P. V. Indiresan
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Thinned array transducer for sonar
The Journal of the Acoustical Society of America, 1983The thinned arrayed transducer for a sonar system includes an array of sonar elements mounted in rows (layers) and columns (staves) on a structure, preferably cylindrical, to form a checkerboard pattern wherein the spacing between adjacent elements in the rows and the columns is equal to or greater than λm /2, where λm is the wavelength of the signal ...
Eugene E. Hill +2 more
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The Journal of the Acoustical Society of America, 1988
A transducer array which includes backing and an acoustic window separated by a plurality of elongated parallel rail members having notches in the sidewalls thereof. Notches in adjacent rail members accommodate a stave member which carries a plurality of transducer elements. A stave member may be placed in the notch and slid into position from which it
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A transducer array which includes backing and an acoustic window separated by a plurality of elongated parallel rail members having notches in the sidewalls thereof. Notches in adjacent rail members accommodate a stave member which carries a plurality of transducer elements. A stave member may be placed in the notch and slid into position from which it
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Sonar array measurement facility
The Journal of the Acoustical Society of America, 1982DED has developed a facility for the accurate calibration of towed line sonar arrays which is small and noise immune enough that it can be installed at any site requiring such measurements. The facility consists of a series of cylindrical transducers submerged in a water tank.
Frederick Reitz, Melvin Main
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The Journal of the Acoustical Society of America, 1991
A mobile sonar surveillance system having a fully populated circular shapedorizontal receiving array steered in edgefired directions with overlapping coverage of beams. The array has a plurality of hydrophones randomly spaced and mounted on a series of parallel lines in the same horizontal plane and is suitable for towing by a single small ship.
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A mobile sonar surveillance system having a fully populated circular shapedorizontal receiving array steered in edgefired directions with overlapping coverage of beams. The array has a plurality of hydrophones randomly spaced and mounted on a series of parallel lines in the same horizontal plane and is suitable for towing by a single small ship.
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The Directivity of Sonar Receiving Arrays
The Journal of the Acoustical Society of America, 1970General expressions are developed for determining the beam patterns and directivity index of arbitrary configurations of hydrophones and results given in the special case of a cylindrical shell array. The limiting case of a continuous distribution of hydrophones is considered and integral relationships are derived for volume and shell distributed array.
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The Journal of the Acoustical Society of America, 1984
A sonar array wherein the capacitance associated with the hydrophones of the array are utilized as shunt elements in an artificial transmission line in order to form an acoustic beam. Series inductance elements to the transmission line are variable with d.c.
Kenneth W. Groves, John D. Lea
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A sonar array wherein the capacitance associated with the hydrophones of the array are utilized as shunt elements in an artificial transmission line in order to form an acoustic beam. Series inductance elements to the transmission line are variable with d.c.
Kenneth W. Groves, John D. Lea
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Parametric array Doppler sonar
IEEE Journal of Oceanic Engineering, 1977A Doppler sonar technique capable of measuring ground speed and distance traveled at extreme ocean depths is described. The technique uses nonlinear acoustic effects to create the narrow beams required. Performance estimates are calculated and parameters for a test system chosen.
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