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:
Apr. 11, 2000
Filed:
Mar. 05, 1997
U.S. Philips Corporation, New York, NY (US);
Abstract
Contactless transmission of information from a passive transponder to a base station takes place in known manner by load modulation in the transponder. The coils of resonant circuits in the base station and in the transponder are coupled to one another, both resonant circuits being tuned as well as possible to the carrier frequency of the base station so that the load modulation of the resonant circuit in the transponder influences the current in the resonant circuit of the base station. Because the two resonant circuits often are not tuned exactly to one another in practice and the transponder is also liable to be moved during the information transmission, it may occur that no signal is recovered by conventional demodulation in the base station. Therefore, according to the invention it is proposed to demodulate an imaginary component and a real component, or different combinations thereof, separately from the antenna signal in the base station and to combine these components by way of a logic circuit which provides notably mutual latching of the two channels. This enables more reliable recovery in the base station of the information transmitted by the transponder.