Accession Number : ADD014700

Title :   Intruder Target Monitoring Sonar Alarm System.

Descriptive Note : Patent, Filed 26 Aug 69, patented 25 Sep 90,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Murphree, Francis J

Report Date : 25 Sep 1990

Pagination or Media Count : 11

Abstract : This patent discloses a system for detecting the presence of intruder targets in an area under sonar surveillance and in which the number of normal targets may vary, including the processing of gated time sample receiver signals through a first monitoring circuit having a counter and comparator means to develop output signals representing deviation of actual time sample count from a normal reference count, and through a second monitoring circuit including additional counter and count trigger means for developing an alarm signal responsive to continued deviation of actual count from reference count over several actual counts in a time sequence of counts such that normal variation of target number will not produce an alarm signal. (R.H.)

Descriptors :   *COUNTING METHODS, *INTRUSION, *MONITORING, *PATENTS, *RECEIVERS, *SONAR, *TARGETS, *WARNING SYSTEMS, CIRCUITS, GATES(CIRCUITS), OCEAN SURVEILLANCE, OUTPUT, PROCESSING, SEQUENCES, SIGNALS, TIME, TRIGGER CIRCUITS, VARIATIONS

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE