EP 0670562 A1 19950906 - Resonant tag label detection system and method utilizing multiple frequency response.
Title (en)
Resonant tag label detection system and method utilizing multiple frequency response.
Title (de)
Detektionssystem mit Resonanzetikette und Antwortverfahren mit mehreren Frequenzen.
Title (fr)
Système de détection avec étiquette résonante et méthode de réponse à fréquence multiple.
Publication
Application
Priority
US 20406694 A 19940301
Abstract (en)
A security system and method for detecting unauthorized removal of items at an exit from a control area. The system includes labels applied to the items, the labels including a plurality of circuit elements, each circuit element being responsive to a different frequency. The labels are modifiable from an initial condition in which all of the circuit elements are actively responsive to their respective frequencies, to a live condition in which at least one but not all of the circuit elements is deactivated and rendered non-responsive to its respective frequency. The labels are also modifiable from the live condition to a dormant condition in which at least one additional circuit element is deactivated and rendered non-responsive to its respective frequency. Different frequencies are generated at the exit of the monitored area, to which said plurality of circuit elements are responsive so as to induce frequency responses by the circuit elements which remain activated. A control unit is responsive to the frequency responses generated by labels in the live condition for generating a control signal.
IPC 1-7
IPC 8 full level
G01V 3/00 (2006.01); G01V 3/12 (2006.01); G01V 15/00 (2006.01); G07C 11/00 (2006.01); G08B 13/24 (2006.01); G09F 3/00 (2006.01)
CPC (source: EP)
G08B 13/242 (2013.01); G08B 13/2437 (2013.01); G08B 13/2445 (2013.01); G08B 13/2448 (2013.01); G08B 13/2482 (2013.01)
Citation (search report)
- [A] US 5081445 A 19920114 - GILL PETER L [US], et al
- [A] EP 0463233 A2 19920102 - CHECKPOINT SYSTEMS INC [US]
- [A] DE 3344782 A1 19840614 - TAKEDA SHIGEKAZU
- [A] US 3967161 A 19760629 - LICHTBLAU GEORGE JAY
Designated contracting state (EPC)
AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE
DOCDB simple family (publication)
EP 0670562 A1 19950906; CN 1129333 A 19960821; JP H0883384 A 19960326
DOCDB simple family (application)
EP 95850044 A 19950228; CN 95103215 A 19950301; JP 4216795 A 19950301