Title: Method for modulating the amplitude of an antenna signal
Application Number: 00807943 Application Date: 2000.03.22
Publication Number: 1351778 Publication Date: 2002.05.29
Approval Pub. Date: 2005.03.09 Granted Pub. Date: 2005.03.09
International Classifi-cation: H03C1/36
Applicant(s) Name: Inside Technologies Address:
Inventor(s) Name: B. Charrat
Attorney & Agent: wang yong
Abstract:
    The invention relates to a method for modulating the amplitude of an antenna signal (Sa) applied to an inductive-type antenna circuit (10) by means of a control circuit (2) comprising binary ports (P1-P4) which can be provided with a high impedance and exhibit a non null internal resistance. According to the invention, the signal (Sp) ensuring that the antenna circuit (10) is supplied with electricity is delivered by at least two ports (P1-P4) of the control circuit and the amplitude of the antenna signal (Sa) is modulated by modifying the output state of at least one of the ports (P1-P4). The invention is particularly suitable for use with contactless chipcard readers.
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