| 摘要 |
An electronic theft detection system has a transmitting antenna and a receiving antenna located on the floor and overhead of a passageway being monitored. The antennas have conductors extending along and crossways of the passageway in staggered arrangement to provide system sensitivity for different paths of egress and different planes of orientation of resonant circuits to be detected. The transmitting antenna consists of a plurality of overlapping loops connected in phase, whereas the receiving antenna consists of a plurality of overlapping loops connected with alternating phase to provide cancellation of extraneous electrical disturbances. |
