Detector for metallic objects in passages open to armed persons - has additional reception winding on each side of entrance to protected area for distinguishing between two objects

摘要

Transmission and reception windings (Tx,Rx) are connected by suitable amplifiers (A,D) to an analysis and control computer (LAC) which compares the signals. An additional reception winding (CC) is positioned on each side of the passage and connected to the computer by its own amplifier (Ac). The additional information supplied by the extra winding unifies the detection sensitivity in the passage area when an attempt is made to carry two metallic objects into the protected area simultaneously so that one of them may escape detection. ADVANTAGE - Device guarantees discrimination between small and large metallic objects passing at same time.