Synchronization of electronic article surveillance systems having metal detection
A method and system are provided for minimizing metal detection signal interference by dividing a standard EAS system metal detection burst timeslot into a plurality of timeslots per burst in order to minimize triggering metal detection false alarm signals between adjacent metal detection systems. The method and system include synchronizing a plurality of metal detection systems by generating a signal having a predefined time duration and segmenting the signal into multiple timeslots per signal. A selected timeslot that is assigned to each of the plurality of metal detection systems is stored and the system performs metal detection using the assigned timeslot.
1. A method of synchronizing metal detection among a plurality of electronic article surveillance (EAS)/metal detection systems by using segmented metal detection burst windows, each metal detection burst window being segmented into multiple timeslots, the method comprising:
receiving an assignment to one of the multiple timeslots;
storing the assigned timeslot; and
synchronizing metal detection by performing metal detection within the assigned timeslot.
2. The method according to claim 1 , wherein the metal detection burst window has a duration substantially equal to a duration of an EAS burst window.
3. The method according to claim 2 , wherein the metal detection burst window is substantially 1.6 ms in duration, the multiple timeslots each are a duration of less than substantially 1.6 ms.
4. The method according to claim 1 , further comprising synchronizing an EAS burst window, EAS receiving window and metal detection burst window of each one of the plurality of EAS/metal detection systems based on a zero crossing point.
5. The method according to claim 1 , wherein each EAS/metal detection system is assigned a different timeslot.
6. The method according to claim 1 , wherein the number of timeslots in each metal detection window is based on a user selection.
7. The method according to claim 1 , wherein the number of timeslots in each metal detection window is based on a number of EAS/metal detection systems to be synchronized.
8. An electronic article surveillance (EAS)/metal detection system having metal detection that is synchronized with metal detection of at least one other EAS/metal detection system by using segmented metal detection burst windows, each metal detection burst window being segmented into multiple timeslots, the system comprising:
a memory; and
a processor configured to:
receive an assignment of one of the multiple timeslots;
cause the memory to store the assigned timeslot; and
perform metal detection within the assigned timeslot.
9. The system according to claim 8 , wherein the metal detection burst window has a duration substantially equal to a duration of an EAS burst window.
10. The system according to claim 9 , wherein the metal detection burst window is 1.6 ms in duration.
11. The system according to claim 10 , the multiple timeslots each are a duration of less than substantially 1.6 ms.
12. The system according to claim 8 , wherein the processor is further configured to select a number of timeslots to segment the metal detection burst window into multiple timeslots.
13. The system according to claim 12 , wherein the processor is further configured to enable a user to manually select the number of timeslots.
14. The system according to claim 12 , wherein the processor selects the number of timeslots based on a number of metal detection systems to be synchronized.
15. A method of synchronizing metal detection in a plurality of electronic article surveillance (EAS)/metal detection systems by using segmented metal detection burst windows, the method comprising:
synchronizing an EAS burst window, an EAS receive window and a metal detection burst window of each EAS/metal detection system based on a signal crossing point, each metal detection burst window being segmented into multiple timeslots, each one of the plurality of EAS/metal detection systems being assigned a respective one of the multiple time slots;
storing, at each EAS/metal detection system, the corresponding assigned timeslot; and
synchronizing metal detection among the plurality of EAS/metal detection systems by performing metal detection, at each EAS/metal detection system, within the corresponding assigned timeslot.
16. The method according to claim 15 , wherein synchronizing the EAS burst window of each EAS/metal detection system at the crossing point includes synchronizing based on at least one of a line power signal and a timing reference.
17. The method according to claim 15 , wherein the metal detection burst window has a duration substantially equal to a duration of EAS burst window.
18. The method according to claim 16 , wherein the metal detection burst window is substantially 1.6 ms in duration.
19. The method according to claim 17 , wherein each of the multiple timeslots are less than substantially 1.6 ms in duration.
20. The method according to claim 15 , wherein the number of timeslots in each metal detection window is based on a number of EAS/metal detection systems to be synchronized.