Research/Patents/US 4959817
US 4959817

INTUDER TARGET MONITORING SONAR ALARM

Assignee

Filed

Aug 26, 1969

Granted

Sep 25, 1990

Location

Abstract

A system for detecting the presence of intruder targets in an area under ar 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.

Source: Google Patents

35 USC §181 Secrecy Order

Imposed

Mar 12, 1982

Rescinded

May 23, 1990

Duration

8 years, 2 months

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Back to patent indexSource: USPTO 35 USC §181 secrecy order records