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LOCAL AND NATIONAL WARNING ALARM SYSTEM

  • US 3,701,024 A
  • Filed: 12/30/1970
  • Issued: 10/24/1972
  • Est. Priority Date: 12/30/1970
  • Status: Expired due to Term
First Claim
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1. A local and national alarm and information communication system comprising:

  • alarm signal generating means for supplying an alarm signal of a predetermined frequency to be broadcast by designated local and regional radio stations, receiving units for use by individuals in the system, each of said units including a first receiving means for receiving said alarm signal and audio signals broadcast by said designated local radio station and a second receiving means for receiving said alarm signal and audio signals broadcast by said designated regional radio station, first switching means connected to said first and second receiving means, said first switching means including a signal gate, means for supplying a reference voltage from said first receiving means to said signal gate, second switching means movable between a first and second position in response to reception of said alarm signal by a said receiving unit, said second switching means being connected to said signal gate and said signal gate being shiftable between a first position wherein signals are passed only from said first position wherein signals are passed only from said first receiving means to said second switching means when said local radio station is broadcasting and a second position in response to the absence of a broadcast signal from said local radio station wherein signals are passed only from said second receiving means to said second switching means, audio broadcasting means connected to said second switching means and operating to broadcast said alarm signal and information when said second switching means is in said second position.

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