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MICROWAVE INTRUSION DETECTING SYSTEM AND APPARATUS

  • US 3,733,602 A
  • Filed: 05/20/1971
  • Issued: 05/15/1973
  • Est. Priority Date: 05/20/1971
  • Status: Expired due to Term
First Claim
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1. A microwave system for detecting the passing of an object through a perimeter and identifying the location of such passing through comprising:

  • a pulse transmitter at one location for generating a series of RF pulses at a definite pulse repetition rate, at least one transponder at a second location spaced from said transmitter and defining a perimeter therewith, said transponder being adapted to receive said RF pulses from said transmitter and to generate and transmit RF pulses corresponding thereto, a receiver at said one location adapted to receive said RF pulses from said transponder, the pulse repetition time of said transmitter being greater than the range time of the transmitted RF pulse to said transponder and return to the receiver, and an indicating system at said receiver for giving one form of signal when one number of RF pulses is not received in response to a specified number of transmitted RF pulses and for giving a second form of signal when a second number of RF pulses is not received in response to the same specified number of transmitted RF pulses.

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