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:
Oct. 23, 2001
Filed:
May. 07, 2001
Gerhard Nebel, Immenstadt, DE;
Volker Güngerich, München, DE;
Andreas Blum, München, DE;
Uwe Weder, Au, DE;
Dierk Eichner, München, DE;
Robert Reiner, Neubiberg, DE;
Gerhard Schraud, Mehring, DE;
Infineon Technologies AG, Munich, DE;
Abstract
A method for demodulating a voltage which has been ASK modulated by changing the amplitude between a low level and a high level, in particular for use during contactless data transmission from a card reader/writer to a smart card, is described. The method is distinguished, in that, in an initialization phase, a first mean value is produced from the high voltage level and a stored partial voltage derived therefrom in order to detect a change to a low voltage level. The change to the low voltage level represents a start value and is detected by a subsequent comparison of the modulated voltage with the first mean value. In a subsequent demodulation phase, a second mean value is produced from the detected low voltage level and the high voltage level in order to demodulate the modulated voltage by comparing the modulated voltage with the second mean value.