Abstract: A method for managing a data transfer system includes recovering energy at peripheral devices, and wireless transfer recovered energy to a base by synchronizing RF signals transmitted by double-loop antennas. Synchronizing includes implementing a listening phase to detect a radio-frequency signal transmitted by said central base, and either sending an RF signal that is synchronous with the detected signal or transmitting a signal at a predetermined frequency depending on whether an RF signal is detected at the base. The method includes, in response to receiving a signal from the peripheral device at that frequency, causing the base to recover the received signal and to re-transmit at the predetermined frequency to the peripheral devices. This signal synchronization enables simultaneous energy transfer from peripheral devices to the central base while avoiding mutually destructive effects between said signals.

Abstract: A method for phase modulation of a carrier signal from a transmitter to a contactless transponder in which data is coded as consecutive symbols, each corresponding to a predefined number of carrier cycles, and in which a symbol time is at least two cycles of the carrier signal includes, at the transmitter, spreading a phase jump of a symbol in relation to a preceding symbol over a first part of the symbol time. The establishment of the phase jump is completed in the first part of the symbol time. The periods of the cycles are constant during a second part of the symbol time.

Abstract: The invention relates to a method for encoding contactless communication data from a transponder to a reader via charge modulation, in the form of a set of modulation patterns, each modulation pattern being a series of charge levels of a predefined length used for physical encoding, having a duration of n carrier periods (Tc), including a series of at least two charge levels, having a minimum pulse width (w) corresponding to the shortest duration of a single charge level in the pattern, and having a retromodulation rate (t) corresponding to the ratio between the retromodulation time and the duration of a pattern, characterized in that the number (k) of patterns is greater than four, the minimum pulse widths (w) of at least two patterns are different, and the retromodulation rates (t) of at least two patterns are different. The invention also relates to a device for implementing the method.

Abstract: A transponder of a contactless data exchange system includes a unit to receive and transmit data provided with at least one first antenna loop and at least one second antenna loop in order to carry out a coupling with a reader. The transponder includes a phase shifter to shift a signal coming from the second loop by a phase shift of K*?, K being an odd integer greater than 0, to produce a phase shifted signal. The transponder includes an adder, to add a signal coming from said first loop and the phase shifted signal to produce a sum signal. The transponder also includes a unit to authorize or prevent a data transmission, depending on the sum signal. A reader of a contactless data exchange system includes a data sending/receiving unit provided with at least one antenna loop, at least one other antenna loop, and a phase shifter.

Abstract: A method for phase modulation of a carrier signal from a transmitter to a contactless transponder in which data is coded as consecutive symbols, each corresponding to a predefined number of carrier cycles, and in which a symbol time is at least two cycles of the carrier signal includes, at the transmitter, spreading a phase jump of a symbol in relation to a preceding symbol over a first part of the symbol time. The establishment of the phase jump is completed in the first part of the symbol time. The periods of the cycles are constant during a second part of the symbol time.

Abstract: The invention relates to a method for encoding contactless communication data from a transponder to a reader via charge modulation, in the form of a set of modulation patterns, each modulation pattern being a series of charge levels of a predefined length used for physical encoding, having a duration of n carrier periods (TC), including a series of at least two charge levels, having a minimum pulse width (w) corresponding to the shortest duration of a single charge level in the pattern, and having a retromodulation rate (t) corresponding to the ratio between the retromodulation time and the duration of a pattern, characterized in that the number (k) of patterns is greater than four, the minimum pulse widths (w) of at least two patterns are different, and the retromodulation rates (t) of at least two patterns are different. The invention also relates to a device for implementing the method.

Abstract: A method for managing a data transfer system includes recovering energy at peripheral devices, and wireless transfer recovered energy to a base by synchronizing RF signals transmitted by double-loop antennas. Synchronizing includes implementing a listening phase to detect a radio-frequency signal transmitted by said central base, and either sending an RF signal that is synchronous with the detected signal or transmitting a signal at a predetermined frequency depending on whether an RF signal is detected at the base. The method includes, in response to receiving a signal from the peripheral device at that frequency, causing the base to recover the received signal and to re-transmit at the predetermined frequency to the peripheral devices. This signal synchronization enables simultaneous energy transfer from peripheral devices to the central base while avoiding mutually destructive effects between said signals.

Abstract: The invention relates to a method for demodulating information emitted by amplitude modulation with two levels by a reader (2) to a transponder (4), comprising a step to determine if this symbol is identical to or is different from the previous symbol, after each symbol.

Abstract: A privacy protection method designed to prevent or authorize a communication between a reader and an RFID label situated in an efficiency zone. In the method a) there is permanent detection of possible variation of an ambient magnetic field in one or more frequency bands allocated to the RFID labels, and b) in the event of detection of an instantaneous variation of the local magnetic field and in the absence of inhibition, a parameter value of a magnetic circuit is modified so that the instantaneous value of the local magnetic field is modified.

Abstract: The invention relates to a contactless data exchange system provided with a transponder comprising: a unit for receiving and transmitting data provided with at least one first antenna loop (110a, 210a) and at least one second antenna loop (110b, 210b) in order to carry out a coupling with a reader (2), means (216, 224a, 224b, 115, 116) pour authorising or preventing the data transmission according to the phase shift (??) between a first signal received by the first loop and a second signal received by the second loop.

Abstract: An antenna includes a central loop and four adjacent coplanar eccentric loops. The central loop creates a magnetic field that is essentially perpendicular to the antenna. The centres of gravity of the four eccentric loops are essentially located on the periphery of the central loop and the eccentric loops are supplied in such a way as to predominantly create a rotating field in a plane parallel to the plane of the antenna. The eccentric loops can be associated in pairs of non-adjacent loops in such a way as to generate electromagnetic fields of opposite phases in the respective pair. In this way, the two loops of a pair can be connected such that the same current flows through them in opposite trigonometric directions. A radiofrequency generator can supply first and second excitation signals alternately on two outputs, respectively to the central loop and to the eccentric loops.

Abstract: The invention relates to a method for demodulating information emitted by amplitude modulation by a reader (2) to a transponder (4) comprising: a step to compare variations of a slaving voltage (Vc) of the transponder (4) with threshold values, and to transform the result of this comparison into an authorized modulation level skip value, a step to add this skip to a previous first modulation level to determine a second modulation level.

Abstract: The invention relates to a method for exchanging information by inductive coupling or without contact between a reader (2) and a transponder (4), comprising a number of demodulation steps, by the transponder, of a transmission signal coming from the reader, each demodulation step being associated with: a detection of a jump of a parameter of the transmission signal, of a first state to a second state among a set of stable states that the parameter of the transmission signal is capable of adopting; a comparison of the magnitude of the jump and/or of the direction of the jump, at one or more predetermined threshold values; an association with the magnitude of the jump and/or with the direction of the jump, at a value independent of the first state, and; a detection of a stabilization at the second state before another demodulation. The invention also relates to a device for carrying out said method.

Abstract: A device and method for estimating a phase reference or a phase shift of a S1 with respect to another reference signal S0.

Abstract: A method and apparatus of information exchange between an interrogator device and a plurality of transponder devices are disclosed. Each of the transponder devices is equipped with a different binary identification code and is located in the magnetic field of the interrogator device, consisting in modifying the duration of the signals and/or the waveform of the signals transmitted by each transponder device according to the ratio between the signal transmitted by the transponder device and the ambient electromagnetic noise.

Abstract: A privacy protection method designed to prevent or authorize a communication between a reader and an RFID label situated in an efficiency zone. In the method a) there is permanent detection of possible variation of an ambient magnetic field in one or more frequency bands allocated to the RFID labels, and b) in the event of detection of an instantaneous variation of the local magnetic field and in the absence of inhibition, a parameter value of a magnetic circuit is modified so that the instantaneous value of the local magnetic field is modified.

Abstract: Each device (1a, 1b, 1c) comprises a processing circuit connected to a first antenna (4), designed to be coupled to an external antenna (3, 5), and a second antenna (5) designed to be coupled to an antenna (4) of a higher-ranking device (1). The system comprises a reading unit and devices (1) having a predetermined ranking. The first antenna (4a) of the rank one device (1a) is coupled to an antenna (3) of the reading unit. Addressing by the reading unit of a device (1c) ranking higher than one is performed by means of the associated lower-ranking devices (1a, 1b). A device (1a1) of predetermined ranking is associated with a sub-set (8a) of higher-ranking devices (1b11, 1b12) so as to form a hierarchical tree structure.

Abstract: A method for secured communication between a transmitter (10) and a receiver (1) in which a range of power levels transmitted by the transmitter (10) a range of frequencies inside which the transmission will occur, (10) are known or detectable by the receiver (1), the method including transmission by the receiver (1) of a power supply signal for the transmitter characterized in that the receiver (I) transmits for at least the whole duration of the transmission, a noise signal which buries the transmission signal, the receiver (1) subtracts from the received signal, the noise signal in order to obtain a useful signal. The invention also includes a receiving device operating according to the method.

Abstract: An antenna includes a central loop and four adjacent coplanar eccentric loops. The central loop creates a magnetic field that is essentially perpendicular to the antenna. The centres of gravity of the four eccentric loops are essentially located on the periphery of the central loop and the eccentric loops are supplied in such a way as to predominantly create a rotating field in a plane parallel to the plane of the antenna. The eccentric loops can be associated in pairs of non-adjacent loops in such a way as to generate electromagnetic fields of opposite phases in the respective pair. In this way, the two loops of a pair can be connected such that the same current flows through them in opposite trigonometric directions. A radiofrequency generator can supply first and second excitation signals alternately on two outputs, respectively to the central loop and to the eccentric loops.

Abstract: Each device (1a, 1b, 1c) comprises a processing circuit connected to a first antenna (4), designed to be coupled to an external antenna (3, 5), and a second antenna (5) designed to be coupled to an antenna (4) of a higher-ranking device (1). The system comprises a reading unit and devices (1) having a predetermined ranking. The first antenna (4a) of the rank one device (1a) is coupled to an antenna (3) of the reading unit. Addressing by the reading unit of a device (1c) ranking higher than one is performed by means of the associated lower-ranking devices (1a, 1b). A device (1a1) of predetermined ranking is associated with a sub-set (8a) of higher-ranking devices (1b11, 1b12) so as to form a hierarchical tree structure.