System for remote information interchange between a portable object and a station

Abstract

The station, in particular a terminal, comprises an oscillator (OS) having a feedback loop (1) and a station inductor element (L10) suitable for conferring a working frequency to the oscillator which varies relative to a rest frequency. The station also includes a station processor connected to the oscillator and capable of processing variations in the working frequency of the oscillator. The portable object, in particular a memory card, includes an electronic circuit which is switchable between an inactive state and an active state in which it sets up a resonant circuit tuned on a frequency which is distinct from the rest frequency while remaining suitable for being coupled inductively with the feedback loop (1) at the rest frequency. The portable object also includes an object processor capable of switching the electronic circuit as a function of the information to be transmitted to the station. The variation in the operating frequency of the oscillator as induced in this way by the switching enables the station processor to deduce the information.

Dependencies are inferred from the claim text.