Accession Number : ADD005196

Title :   Scanner.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON D C

Personal Author(s) : Holzschuh,Jack E

Report Date : 22 May 1978

Pagination or Media Count : 19

Abstract : The scanner delays the outputs of an array of hydrophones so that sound arriving from a particular angle with respect to the array axis will add in phase from all the hydrophones and give a large output. The output of each hydrophone is first amplified, then phase shifted. The output of the phase shifter is then added to the amplified output from the next hydrophone and this output is then phase shifted again. Using this technique requires that all the phase shifters have the same linear rate of change of phase shift versus time, and therefore, a variation of either the resistance or the reactance of a circuit or both. One means to get the required linear time rate of change of phase shift involves a change of reactance in a small toroid coil which has two windings: a control winding and an inductance winding. As d-c current increases in the control winding, it decreases the permeability of the core, thereby decreasing the inductance of the inductance winding. This decrease in inductance then gives the required change in reactance. (Author)

Descriptors :   *Patent applications, *Scanners, *Hydrophones, Phase shift, Naval research

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE