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Intrusion detection system and a method therefor

  • US 4,882,567 A
  • Filed: 09/29/1988
  • Issued: 11/21/1989
  • Est. Priority Date: 09/29/1988
  • Status: Expired due to Term
First Claim
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1. An intrusion detection system comprisinga first passive detecting means for detecting the presence of an intruder in a volume of space and for generating a first signal in response to the detection of said intruder;

  • a second detecting means for detecting the presence of said intruder in said volume of space and for generating a second signal in response to the detection of said intruder;

    a timing means for receiving said first signal and for generating a control signal after a period of delay in response to said first signal;

    a signal switch means for receiving said control signal and for activating said second detecting means by supplying power thereto in response to said control signal; and

    logic means for receiving said first and said second signals and for producing an alarm signal in response thereto, said alarm signal indicative of the detection of the presence of said intruder in said volume of space.

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