Commissariat a L'energie Atomique

Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Elisabeth Crochon

Jacques Reverdy

Thierry Thomas

Sylvain Bacquet

Florian Pebay-Peyroula

François Dehmas

François Vacherand

Gérard Robert

Fran&ccedil;ois Vacherand

Olivier Savry

Francois Dehmas

Mathieu Des Noes

G&eacute;rard Billiot

Ricardo Malherbi Martins

Yann Têtu

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.

Data transfer system and associated management method

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.

Method for the phase modulation of a carrier signal transmitted from a transmitter to a contactless transponder, and device for implementing same

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 (T), 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.

Method for encoding contactless communication data from a transponder to a reader via charge modulation, in the form of a set of patterns and device for implementing same

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*&#x3c0;, 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.

Device for the secure contactless data exchange between a reader and a card

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

Two-level demodulation method and device

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.

Contactless privacy protection device

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.

Flat plate antenna with a rotating field, comprising a central loop and eccentric loops, and system for identification by radiofrequency

The invention relates to a method for demodulating information emitted by amplitude modulation by a reader () to a transponder () comprising:

Multi-level demodulation method and device

A device and method for estimating a phase reference or a phase shift of a Swith respect to another reference signal S.

Device and method for detecting the phase of a signal

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.

Method and system of information exchange between an interrogator device and transponder devices that takes into account the level of ambient noise

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

System comprising a plurality of devices that can be addressed by radio frequency, and method for addressing by activation of a transparent mode

A method of information transmission from an interrogator system to portable objects. The information is transmitted through ternary amplitude modulation and positional pulse coding. A frame is made up of a Start Of Frame (SOF) marker made up of two like-polarity pulses, patterns that transmit binary symbols and are composed of two opposite-polarity pulses, and lastly an End Of Frame (EOF) marker that is made up only of a single pulse. The present invention is notably intended for interrogating radio frequency (RFID) tags.

Method for transmitting data from an interrogating device to portable objects

This method of identification between an interrogation system () such as an arch and labels (E) placed on objects to be identified and called upon to pass through the interrogation field () functions by the sending of control signals from the interrogator () to the labels (E) so that the latter transmit their codes. The known interrogation mode in which the codes are supplied bit by bit and the labels responding simultaneously are inhibited in turn so that only one is active and identified at any one time, is preceded by an identification test during which all the labels send their code at one go all at the same time, which allows immediate identification if only one label is present. When a label has been identified, the interrogator () isolates it in order to exchange particular information with it.

Method and device for remote identification

Multiple read method and system for a set of tags bearing distinct ID codes

The invention relates to a method and system for reading a dynamic set of tags present in the electromagnetic field of a polling device, consisting in updating cyclically a list of tags present in the electromagnetic field and minimizing the time for checking the presence of tags already identified, by assigning to each of these tags a sequence number whose binary size is significantly smaller than that of the ID code and that allows to realize a &ldquo;call&rdquo; of the tags present by enumeration.

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Poisat, France

Elisabeth Crochon