Communication between electromagnetic transponders
AssigneeSTMicroelectronics S.r.l.
InventorsPierre Rizzo, Jerome Conraux
Life of this patent
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Abstract
An electromagnetic transponder intended to draw the power necessary to its operation of from a field radiated by a terminal of transmission of a carrier at a first supply frequency and to back-modulate the received signal at the rate of a sub-carrier at a second frequency lower than the first one, and comprising means capable of demodulating and decoding signals modulated by said sub-carrier, as well as a system of communication between such transponders.
Claims20
An electromagnetic transponder intended to draw power necessary to its operation from a field radiated by a terminal of transmission of a carrier at a first frequency, and to back-modulate a received signal at a rate of a sub-carrier at a second frequency lower than the first one, comprising means capable of demodulating and decoding signals modulated by said sub-carrier.
A system of contactless and wireless communication between at least two electromagnetic transponders having no independent power supply, wherein each transponder comprises means capable of drawing power necessary to a supply of its circuits from an electromagnetic field at a first frequency radiated by at least one read/write terminal, and means for demodulating and decoding signals transmitted by another transponder in modulation of a sub-carrier at a second frequency.
A transponder, comprising:
- a first circuit to receive a first signal having a first frequency and to provide power from the first signal;
- a second circuit coupled to the first circuit to receive a second signal having a second frequency;
- a third circuit coupled to the first circuit and coupled parallel to the second circuit to receive a third signal having a third frequency, the third signal being received from another transponder;
- and
- a fourth circuit coupled to the second and third circuits to respectively process the demodulated second and third signals.
A method for a transponder, the method comprising:
- receiving a first signal having a first frequency and providing power from the first signal;
- receiving a second signal having a second frequency and demodulating the received second signal;
- receiving a third signal having a third frequency from another transponder and distinguishing the received third signal from the second signal and demodulating the received third signal;
- and
- processing the demodulated second or third signals.
A system for a transponder, the system comprising:
- a means for receiving a first signal having a first frequency and providing power from the first signal;
- a means for receiving a second signal having a second frequency and demodulating the received second signal;
- a means for receiving a third signal having a third frequency from another transponder and distinguishing the received third signal from the second signal and demodulating the received third signal;
- and
- a means for processing the demodulated second or third signals.
Dependencies are inferred from the claim text.