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Alarm-equipped electronic article surveillance system

  • US 5,808,548 A
  • Filed: 04/04/1996
  • Issued: 09/15/1998
  • Est. Priority Date: 04/10/1995
  • Status: Expired due to Fees
First Claim
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1. An alarm-equipped electronic article surveillance system comprising:

  • a signal transmitter device located close to the gates of access to an area of interest; and

    a tag for attachment to an article of merchandise under surveillance;

    said signal transmitter device including a signal generator for generating a modulated signal by modulating a carrier frequency signal with a modulation signal having a frequency, a signal transmitter for transmitting said modulated signal, and a transmitting antenna;

    said tag includes a receiving antenna, a signal receiver for selectively receiving said modulated signal, a frequency selector for selecting said modulation signal out of said modulated signal, an alarm generator operable for generating an output indicative of an alarm condition, and an alarm negator for negating the operation of said alarm generator in response to receiving a control signal having a frequency, wherein said frequency of said control signal is the same frequency as said frequency of said modulation signal.

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