The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 16, 2000
Filed:
Sep. 29, 1997
Terry Clancy, Bensheim-Zell, DE;
David Stocks, Royston, GB;
Esselte Meto International GmbH, Heppenheim, DE;
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)).