Apparatus for the surveillance of an electronic security element in an interrogation zone
US6064296A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 29, 1997 |
| Grant date | May 16, 2000 |
| Priority date | — |
| Expiry date | Sep 29, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2471
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The present invention is directed to an apparatus for the surveillance of an electronic security element in an interrogation zone. The apparatus includes a transmitting device emitting at least one periodic interrogation signal into the interrogation zone, with the interrogation signal causing the security element to deliver a characteristic signal, a receiving device receiving the characteristic signal, and a computing/control unit evaluating the signals r(s) received from the receiving device and producing an alarm when the presence of the security element is established. The apparatus improves the detection of articles equipped with electronically detectable security elements within an interrogation zone, in that the computing/control unit evaluates the received signal with respect to amplitude and phase (I component and Q component), that it detects and determines by approximation an interference signal (fd(s)) occurring in the received signal, and then it removes the interference signal (fd(s)) from the received signal (r(s)).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.