Capacitive modulation in a electromagnetic transponder

摘要

The transponder is of the type having an oscillating circuit (L2,C2) in front of a rectifier circuit (13) designed to produce a continuous voltage (Va) to an electronic circuit (17). The circuit (17) includes means for emitting digital data codes. The transponder has two capacitive modulation circuits (C2,K1; C4,K2) respectively associated with each end terminal of an inductive part (L2) of the oscillating circuit. A reference terminal of each modulating circuit is connected to a reference voltage (15) of the electronic circuit supply