摘要 |
An article theft detection system for identifying which of two adjacent passageways a protected article passes. Each passageway is provided with spaced apart interrogation and receiver antennas, but a single receiver antenna services both passageways. Multiplexing is used to energize the interrogation antennas in alternate sequence. The single receiver antenna is connected to a single receiver whose output is connected through switches, synchronized with the interrogation multiplexing, to separate alarms for each passageway.
|