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Radar intrusion detection system

  • US 4,952,939 A
  • Filed: 02/16/1989
  • Issued: 08/28/1990
  • Est. Priority Date: 02/16/1989
  • Status: Expired due to Term
First Claim
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1. An intrusion detection system comprising:

  • means transmitting an r.f. signal formed from a continuous wave modified by phase changes at selected instants;

    means providing a code sequence to control the selected instants;

    means receiving a portion of the transmitted signal which may have been modified by the presence of a target; and

    means mixing the received signal with a delayed replica of the transmitted signal to establish a detection zone external to the space between the antennas, the delay establishing the range of the detection zone;

    whereby the system provides an enhanced response relating to objects in the detection zone.

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