Accession Number : AD0746690

Title :   An Octave Bandwidth Constant Beamwidth Underwater Receiving Array.

Descriptive Note : Technical memo.,

Corporate Author : TEXAS UNIV AUSTIN ELECTRONICS RESEARCH CENTER

Personal Author(s) : Holden,Robert J. ; Hixson,E. L.

Report Date : MAY 1972

Pagination or Media Count : 62

Abstract : A method for providing a constant beamwidth over an octave frequency bandwidth for an acoustical array is presented. This is accomplished by designing an array of the desired characteristics at lower band limit and a half scale model that will have the identical characteristics at twice that frequency. The outputs of these arrays are combined after filtering. The filter responses are derived by imposing the constant beamwidth constraints. Such an array was implemented to cover the octave 10 to 20 KHz. Two 5-element broadside arrays were combined but because of redundancy only 7 elements were required. Because of poor element frequency response and nonuniformity, the on-axis frequency response was not flat over the octave. However, the measured beamwidth was 20 plus or minus 1 degrees for a design value of 20.8 degrees. (Author)

Descriptors :   (*SONAR RECEIVERS, SONAR ARRAYS), PIEZOELECTRIC TRANSDUCERS, LOW PASS FILTERS, HIGH PASS FILTERS, CIRCUITS, PERFORMANCE(ENGINEERING)

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE