Alarm-equipped electronic article surveillance system
First Claim
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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Accused Products
Abstract
An alarm-equipped electronic article surveillance system which is easy to handle, which provides against the triggering of false alarm, and which reliably surveys articles of interest against theft. The system comprises a signal transmitter device located close to the gates of access to an area of interest, and a plurality of tags each attached to an article of merchandise under surveillance. The signal transmitter device includes a signal generator for generating a modulated signal by modulating a carrier frequency signal with a modulation signal, a signal transmitter for transmitting the modulated signal, and a transmitting antenna. The plurality of tags each include a receiving antenna, a signal receiver for selectively receiving the modulated signal, a frequency selector for selecting the modulation signal out of the modulated signal, an alarm generator operable for generating an output indicative of an alarm condition, and an alarm negator for negating the operation of the alarm generator.
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Citations
23 Claims
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1. An alarm-equipped electronic article surveillance system comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A tag for attaching to an article of merchandise in an alarm-equipped electronic article surveillance system, said tag comprising:
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a receiving antenna; a signal receiver for selectively receiving a first signal generated by a signal transmitter device; 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, said alarm negator including a light receiving element for receiving an optical control signal, said alarm negator negates the operation of said alarm generator in response to receiving said optical control signal. - View Dependent Claims (12, 13, 14, 15)
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16. A tag for attaching to an article of merchandise in an alarm-equipped electronic article surveillance system, said tag comprising:
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a receiving antenna; a signal receiver for selectively receiving a first signal generated by a signal transmitter device; 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, said alarm negator includes a heat exchanger plate and a heat sensing element contacting the heat exchanger plate, wherein the alarm negator circuit negates the operation of said alarm generator in response to a heat source from a tag control unit contacting the heat exchanger plate to raise the temperature of the heat exchange plate as sensed by the heat sensing element. - View Dependent Claims (17, 18)
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19. A tag for attaching to an article of merchandise in an alarm-equipped electronic article surveillance system, said tag comprising:
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a receiving antenna; a signal receiver for selectively receiving a modulated signal transmitted by a signal transmitter device, said modulated signal generated by modulating a carrier frequency signal with a modulation signal having a frequency; 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. - View Dependent Claims (20, 21, 22, 23)
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Specification