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Alarm system for sensing and vocally warning of an unauthorized approach towards a protected object or zone

  • US 4,987,402 A
  • Filed: 10/11/1989
  • Issued: 01/22/1991
  • Est. Priority Date: 01/21/1987
  • Status: Expired due to Term
First Claim
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1. A vocal alarm system coupled to an object to be protected, said alarm system comprising:

  • means for generating a radio frequency (RF) field within a protected area surrounding said object or zone;

    means for sensing an interference within said RF field of the type created by entry of a person within said RF field;

    synthetic voice generation means for generating a first vocal warning in response to the sensing of an interference within said RF field, said vocal warning providing audible instructions that alert the person that he or she has entered a protected are and that he or she must exit or leave the protected area in order to prevent an alarm from sounding; and

    alarm generation means responsive to said sensing means for sounding an alarm in the event the person has not left the protected area, as detected by said sensing means, within a specified time period subsequent to first sensing an interference within said RF field.

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