Wireless EAS Synchronization Using Master Timing Source
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Solution Overview
Problem
Existing electronic article surveillance (EAS) systems face challenges in synchronizing multiple interrogation devices across independent AC power sources, leading to potential interference and the need for a method to share data such as alarm information and people counters without increasing complexity.
Innovation Solution
A wireless synchronization system using a synchronization master radio and phase-locked loops (PLLs) to synchronize data transmission and reception among remote EAS units, allowing for communication via wireless or wired media, and employing repeaters to extend the network coverage and enable data transfer during designated periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple independent AC power sources are used to provide power to multiple EAS systems, then the system can operate in locations without reliable AC power (e.g., using independent generators), but the multiple independent AC power sources cannot be used to synchronize the EAS systems, leading to potential interference among the systems
Solution Approach 1:
The patent introduces a master timing source as an intermediary device that generates a synchronization signal to coordinate multiple EAS systems powered by independent AC sources. This master timing source acts as a mediator that translates unsynchronized power sources into synchronized operation, preventing interference while maintaining the ability to operate with independent power sources.
2Reliability
If a master timing source is used to synchronize EAS systems, then interference among multiple EAS systems is reduced, but the system complexity increases due to the need for additional synchronization infrastructure
Solution Approach 1:
The master timing source is designed to perform multiple functions: it not only provides timing synchronization for EAS systems but also can serve as a communication node and can be integrated with existing power distribution infrastructure. This multi-functionality reduces the need for separate dedicated synchronization infrastructure, thereby reducing overall system complexity.
3Reliability
If EAS systems use periodic interrogation signal transmission followed by listening periods, then tags can respond to interrogation signals, but the systems cannot communicate data such as alarm information and people counters without adding complexity and inefficiency
Solution Approach 1:
The patent combines the data communication function with the existing periodic interrogation signal transmission by modulating data onto the interrogation signals or utilizing the listening periods for bidirectional communication. This merging of functions allows alarm information and people counter data to be transmitted using the existing signal structure, avoiding the need for separate communication protocols and reducing overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively synchronizes multiple EAS units across diverse power sources, reducing interference and enabling efficient data communication, allowing for coordinated operation and alert generation without adding complexity to the interrogation function.
Implementation Method 1
Each of the remote EAS units includes a phase-locked loop synchronized to the master synchronization signal
Implementation Method 2
magneto-acoustic EAS systems operate by periodically transmitting an interrogation signal which stimulates the magneto-acoustic tag to induce a responsive signal
Data Source
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AI summary
A method and system are provided for synchronizing a plurality of electronic article surveillance ("EAS") units and providing wireless data transfer by the EAS units. The invention generates a master synchronization signal, transmits the master synchronization signal to the plurality of EAS units and applies the master synchronization signal to trigger a synchronization packet reception period. A beginning of a wireless data transfer period is calculated and initiated based on the triggering of the synchronization packet reception period.