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AssigneeCommissariat A L'Energie Atomique Et Aux Energie Alternatives
InventorsFlorian Pebay-Peyroula, Elisabeth Crochon, Jacques Reverdy, Thierry Thomas
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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.
1-16. (canceled)
A method for encoding contactless communication data from a transponder to a reader by load modulation, in the form of a set of modulation patterns, said method comprising selecting each pattern to be a succession of load levels of a predefined length used for physical encoding and to have a duration equal to the product of a carrier period and a number of carrier steps, to comprise a succession of at least two load levels, to have a minimum pulse width corresponding to a shortest duration in terms of number of carrier steps of a same load level in the pattern, and to have a retromodulation rate corresponding to a ratio between the retromodulation time and the duration of a pattern, wherein the number of patterns is greater than four, the minimum pulse widths of at least two patterns are different, and the retromodulation rates of at least two patterns are different.
An apparatus comprising a retromodulation device, the apparatus comprising a shunt transistor and an n-bit carrier frequency shift register, the shunt transistor being arranged in series with a load impedance at terminals of an antenna and having a gate connected to the n-bit carrier frequency shift register, the register having an input linked to a data line in parallel with patterns to be transmitted, each pattern being a succession of load levels of a predefined length used for the physical encoding, having a duration equal to the product of a carrier period and a number of carrier steps, comprising a succession of at least two load levels, having a minimum pulse width corresponding to a shortest duration in terms of number of carrier steps of a same load level in the pattern, and having a retromodulation rate corresponding to a ratio between the retromodulation time and the duration of a pattern, wherein the number of patterns is greater than four, the minimum pulse widths of at least two patterns are different, and the retromodulation rates of at least two patterns are different.
Dependencies are inferred from the claim text.