EP 0541480 B1 19960724 - Label detection for an electronic surveillance system
Title (en)
Label detection for an electronic surveillance system
Title (de)
Detektionsvorrichtung für Warendiebstahlsicherungsetiketten
Title (fr)
Dispositif de détection d'étiquettes de surveillance électronique
Publication
Application
Priority
- CH 109892 A 19920403
- CH 244692 A 19920804
- CH 318591 A 19911031
Abstract (en)
[origin: EP0541480A1] The device for detecting labels (21) which serve to protect goods (20) against theft and which are provided with an electric resonant circuit with a resonant frequency in the MHz range comprises a plurality of pairs of transmitting and receiving antennas (8-13) which in each case delimit passages (5-7) which are to be kept under surveillance. Electromagnetic waves whose frequency is swept in sweep cycles beyond the pre-defined resonant frequency of the labels are in each case radiated by the transmitting antennas (8, 10, 12) of the pairs. The sweep cycles of all pairs are synchronised with one another. A receiving circuit (17-19) which detects the presence of a label is connected to the receiving antenna (9, 11, 13) of each pair. To simplify installation, it is proposed according to the invention that the RF oscillations radiated via the transmitting antennas as electromagnetic waves are generated by decentralised RF generators (14-16) in each case individually assigned to the transmitting antennas and that the sweep cycles are synchronised with one another using a synchronisation signal with at least one frequency in the LW range which is generated in a central unit (22) and fed to the RF generators. <IMAGE>
IPC 1-7
IPC 8 full level
G08B 13/22 (2006.01); G08B 13/24 (2006.01)
CPC (source: EP US)
G08B 13/2414 (2013.01 - EP US); G08B 13/2471 (2013.01 - EP US); G08B 13/2477 (2013.01 - EP US); G08B 13/2488 (2013.01 - EP US)
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 0541480 A1 19930512; EP 0541480 B1 19960724; AT E140813 T1 19960815; DE 59206809 D1 19960829; JP 2821068 B2 19981105; JP H0620165 A 19940128; US 5337040 A 19940809
DOCDB simple family (application)
EP 92810789 A 19921015; AT 92810789 T 19921015; DE 59206809 T 19921015; JP 27725392 A 19921015; US 95999192 A 19921013