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Police radar signal detection circuitry for a police radar warning receiver

  • US 4,750,215 A
  • Filed: 06/24/1986
  • Issued: 06/07/1988
  • Est. Priority Date: 06/24/1986
  • Status: Expired due to Term
First Claim
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1. A receiver adapted to distinguish between pulsed and continuous signals from a fixed frequency source and pulsed and continuous signals from a variable frequency source, the receiver comprising:

  • oscillator means for generating an oscillator signal which is swept in frequency between a first frequency and a second frequency;

    mixer means for mixing said oscillator signal with received pulsed and continuous signals to provide IF signals;

    discriminator means which is responsive to said IF signals for generating output signals having a voltage level which varies relative to a threshold voltage;

    first circuit means which is responsive to said output signals for providing evaluation signals which are alternatively in either a first state or a second state at a given time, said state being indicative of the voltage level of said output signal relative said threshold voltage at said given time; and

    second circuit means which is responsive to said evaluation signals for indicating that the received signals are from a fixed frequency source when said evaluation signals are in only said first state throughout a first predetermined time interval and are in only said second state throughout a third predetermined time interval, said third time interval begining a second predetermined time interval after said first time interval ends.

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