Antenna signal amplitude modulation method
AssigneeInside Technologies
InventorBruno Charrat
Life of this patent
Estimating the term…
Abstract
A method for modulating the amplitude of an antenna signal applied to an inductive-type antenna circuit by a control circuit having binary ports that can be set to high impedance and with a non-zero internal resistor. The signal providing the electric power supply of the antenna circuit is delivered by at least two ports of the control circuit, and the amplitude of the antenna signal is modulated by changing the output state of at least one of the ports. Particularly applied to contactless smart card readers.
Claims8
Method for modulating the amplitude of the antenna signal of an inductive antenna circuit comprising a coil, by means of a control circuit comprising binary ports that can be set to high impedance state and with a non-zero internal resistor, characterised in that the antenna circuit is electrically powered by at least two ports of the control circuit, and in that it comprises steps of:
- setting the ports providing the electric supply of the antenna circuit to “1”, to supply the antenna circuit at full power level, and
- changing the state of at least one of the ports providing the electric supply of the antenna circuit, to modulate the amplitude of the antenna signal.
Dependencies are inferred from the claim text.