Metal detector integrated with a transducer detector for access control..

摘要

The system includes an audio frequency type metal detector(foi) acting as a receiver in a circuit which processes coded signal data transmitted at a frequency(foi+f) by a transducer card(3). This card(3) is activated by transmitter groups(Txi) of the metal detector. The card(3) activates a logic unit which permits the movement of authorised personnel through the controlled passage. The system also includes an active type transducer integrated on the card(3) with windings(L) terminated in high impedance circuits for the signals at frequency(foi).