Evaluation of the number of electromagnetic transponders in the field of a reader
First Claim
1. A terminal for generating a high-frequency electromagnetic field by means of an oscillating circuit, adapted to cooperating with at least one transponder when said transponder enters this field, and including:
- means for regulating a signal phase in the oscillating circuit with respect to a reference value; and
means for evaluating, based on a measurement of a current in the oscillating circuit, a minimum number of transponders present in the field.
1 Assignment
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Accused Products
Abstract
A terminal for generating a high-frequency electromagnetic field by an oscillating circuit, adapted to cooperating with at least one transponder when the transponder enters this field, and a method for establishing a communication between the devices, including circuitry for regulating the signal phase in the oscillating circuit with respect to a reference value and circuitry for evaluating, based on a measurement of the current in the oscillating circuit, the minimum number of transponders present in the field.
52 Citations
8 Claims
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1. A terminal for generating a high-frequency electromagnetic field by means of an oscillating circuit, adapted to cooperating with at least one transponder when said transponder enters this field, and including:
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means for regulating a signal phase in the oscillating circuit with respect to a reference value; and
means for evaluating, based on a measurement of a current in the oscillating circuit, a minimum number of transponders present in the field. - View Dependent Claims (2, 3, 4, 5)
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- 6. A method for establishing at least one communication between a terminal generating a high-frequency magnetic field and an electromagnetic transponder, including periodically sending a request sequence until at least one transponder entering the field sends an acknowledgement, and of evaluating, based on a measurement of a current in an oscillating circuit of the terminal, a minimum number of transponders likely to be present in the field.
Specification