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Emergency Radio Warning System

  • US 3,864,674 A
  • Filed: 12/18/1972
  • Issued: 02/04/1975
  • Est. Priority Date: 12/18/1972
  • Status: Expired due to Term
First Claim
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1. An emergency radio warning system comprising:

  • a sensor operable upon an emergency condition;

    means operated by the sensor in response to an emergency condition for generating and transmitting a radio signal having a predetermined frequency;

    means for modulating the generating and transmitting means with an identification signal having one or more simultaneously generated frequencies selected from a group of four frequencies in accordance with an identifying binary coded decimal digit;

    said modulating means including one or more oscillator circuits, each having in circuit a tuning fork filter resonant at a respective selected frequency;

    means for receiving the modulAted radio signal and detecting the identification signal;

    said receiving and detecting means including four tuning fork filters resonant at the respective four frequencies; and

    means responsive to the identification signal for displaying the decimal digit corresponding to the detected identification signal to indicate the location of the emergency condition.

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