Adaptation of the transmission power of an electromagnetic transponder reader
First Claim
1. A terminal for generating an electromagnetic field adapted to cooperating with at least one transponder when the at least one transponder is within said electromagnetic field and including an oscillating circuit adapted to receiving a high frequency A.C. excitation voltage, including:
- means for maintaining a constant phase relationship between a signal in the oscillating circuit and a reference signal;
means for determining an instantaneous information relative to an instantaneous magnetic coupling between the transponder and the terminal; and
means for adapting a power of the electromagnetic field according to at least said instantaneous information.
1 Assignment
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Accused Products
Abstract
A terminal for generating an electromagnetic field adapted to cooperating with at least one transponder when the latter enters its field and including an oscillating circuit adapted to receiving a high-frequency A.C. excitation voltage, circuitry for regulating the signal phase in the oscillating circuit with respect to a reference value, circuitry for determining an instantaneous information relative to the magnetic coupling between the transponder and the terminal, and circuitry for adapting the electromagnetic field power according to at least said present information.
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Citations
36 Claims
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1. A terminal for generating an electromagnetic field adapted to cooperating with at least one transponder when the at least one transponder is within said electromagnetic field and including an oscillating circuit adapted to receiving a high frequency A.C. excitation voltage, including:
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means for maintaining a constant phase relationship between a signal in the oscillating circuit and a reference signal;
means for determining an instantaneous information relative to an instantaneous magnetic coupling between the transponder and the terminal; and
means for adapting a power of the electromagnetic field according to at least said instantaneous information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A terminal for generating an electromagnetic field, the terminal being adapted to cooperate with a transponder when the transponder is within the electromagnetic field, the terminal comprising:
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an oscillating circuit; and
a phase regulating circuit to maintain a constant phase relationship between a current in the oscillating circuit and a reference signal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of controlling a power of an electromagnetic field generated by an oscillating circuit of a terminal adapted to cooperate with a transponder when the transponder is within the electromagnetic field, the method comprising an act of:
(A) maintaining a constant phase relationship between a current in the oscillating circuit and a reference signal. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
Specification