| 摘要 |
<p>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.</p> |
