초록 ▼

Operation of similar electronic article surveillance (EAS) systems in proximity to each other may result in false alarms or system “shut-downs”as a result of signals transmitted from one system being detected in the receiver circuits of the other systems. This may especially occur with EAS systems i

Operation of similar electronic article surveillance (EAS) systems in proximity to each other may result in false alarms or system “shut-downs”as a result of signals transmitted from one system being detected in the receiver circuits of the other systems. This may especially occur with EAS systems in which the receivers are only activated during quiescent intervals between transmitted bursts, such that if the systems are unsychronized, the transmitted bursts of the one system may occur during the quiescent intervals of the other system. In the present invention, synchronization is effected by responding to RF detected during the quiescent intervals and preventing the transmitted bursts from occurring during the quiescent intervals of the other system.

대표청구항 ▼

An electronic article surveillance system comprising transmitting means for producing in an interrogation zone periodic interrogation signals having bursts of RF followed by quiescent intervals, receiving means for detecting during said quiescent intervals a signal generated by a marker in response

An electronic article surveillance system comprising transmitting means for producing in an interrogation zone periodic interrogation signals having bursts of RF followed by quiescent intervals, receiving means for detecting during said quiescent intervals a signal generated by a marker in response to said interrogation signals, and means responsive to radiated electromagnetic energy for synchronizing the production of bursts of RF by said transmitting means with bursts of RF from another like system, thereby preventing bursts of RF from said transmitting means from occurring during quiescent intervals of the interrogation signals of said another system so that such bursts cannot produce a false alarm or shut down a system as a result of being detected by the receiving means of said another system.