Method for synchronization between systems
First Claim
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1. A method for synchronizing the operation of a plurality of EAS systems, comprising:
- receiving in said plurality of EAS systems an single RF synchronization signal from a remote source;
detecting a time difference between said RF syncyronization signal and zero crossing of at least one of a power line current and voltage and storing said difference in a memory;
in response to receiving said RF synchronization signal, transmitting in each of said EAS systems a synchronized exciter pulse for exciting a remotely located identification marker; and
a predetermined time after transmitting said exciter pulse, enabling in each of said EAS systems a receiver for detecting a characteristic response of said indentification marker.
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Abstract
An apparatus for synchronized operation of a plurality of EAS systems. The system includes two or more EAS systems. Each EAS system has a receiver for receiving the same RF synchronization signal sent from a remote source, a transmitter for transmitting a marker exciter pulse and an exciter pulse receiver. The transmitter and exciter pulse receiver of each of the EAS systems are selectively enabled a predetermined time after receiving the RF synchronization signal so that all EAS systems in a localized area can be synchronized with one another.
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Citations
20 Claims
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1. A method for synchronizing the operation of a plurality of EAS systems, comprising:
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receiving in said plurality of EAS systems an single RF synchronization signal from a remote source;
detecting a time difference between said RF syncyronization signal and zero crossing of at least one of a power line current and voltage and storing said difference in a memory;
in response to receiving said RF synchronization signal, transmitting in each of said EAS systems a synchronized exciter pulse for exciting a remotely located identification marker; and
a predetermined time after transmitting said exciter pulse, enabling in each of said EAS systems a receiver for detecting a characteristic response of said indentification marker. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An apparatus for synchronized operation of a plurality of EAS systems, comprising:
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a plurality of EAS system, each having a receiver for receiving a same RF synchronization signal sent from a remote source, a transmitter for transmitting an exciter pulse for exciting an indentification marker in response to said receiver receiving said RF synchronization signal, an exciter pulse receiver enable a predetermined time after transmitter transmits said exciter pulse receiver enabled a predetermined time after said transmitter transmits said exciter pulse, for detecting a characteristic response of said indentification marker, and a local power line zero crossing detector and a difference detector for detecting a time difference between said RF synchronization signal and a zero crossing of at least one of a power line current and voltage. - View Dependent Claims (13, 14, 15, 16, 18, 19)
14.The apparatus according to claim 12, wherein said remote source is a second EAS system. -
14. The apparatus according to claim 12, wherein said RF synchronization signal is triggered by a zero crossing of at least one of a power line current and voltage.
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15. The apparatus according to claim 12, wherein said remote source is a satellite.
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16. The apparatus according to claim 12, wherein said remote source is a geographically remote radio transmitter.
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18. The apparatus according to claim 12, wherein said RF synchronization signal is a local timing signal.
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19. The apparatus according to claim 12, wherein said RF synchronization signal received by said EAS system is encoded.
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17. The apparatus according to claim 17, wherein the remote source transmits an absolute timing signal.
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20. A method for synchronized operation of a plurality of EAS systems comprising:
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receiving in each said plurality of EAS systems a same RF synchronization signal;
processing said RF synchronization signal in each of said plurality of EAS systems to determine a time offset relative to a predetermined angle of at least one of a power line voltage and current for each said EAS systems;
storing in each said EAS system a time offset in a memory location; and
transmitting in each of said EAS systems an exciter pulse for exciting a remotely located identification marker in accordance with said time offset.
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Specification