Transponder positioning aid
First Claim
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1. A method to assist a user positioning an electromagnetic transponder with respect to a terminal, comprising:
- calculating by the terminal a first ratio relating a first coupling factor between the electromagnetic transponder and the terminal to a selected optimum coupling factor, the selected optimum coupling factor based on a first resistive load value;
storing the calculated first ratio;
controlling a variable capacitance circuit of the terminal with control information generated by a phase interval detection circuit, the phase interval detection circuit arranged to receive data representative of current flowing through a measurement element of the terminal, the current flowing through the measurement element of the terminal corresponding to a current coupling factor between the electromagnetic transponder and the terminal;
calculating by the terminal a current ratio relating the current coupling factor between the electromagnetic transponder and the terminal to the selected optimum coupling factor;
comparing by the terminal said current ratio with said first ratio; and
controlling at least one output data element according to said comparison.
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Abstract
A method for assisting with positioning of an electromagnetic transponder by a user with respect to a terminal, wherein: a current value of a ratio of the current coupling factor between the transponder and the terminal to an optimum coupling factor with a first resistive load value is calculated and stored; the current value is compared with a previous value of this ratio, stored in a previous iteration; and data elements intended for the user are controlled according to the comparison.
64 Citations
19 Claims
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1. A method to assist a user positioning an electromagnetic transponder with respect to a terminal, comprising:
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calculating by the terminal a first ratio relating a first coupling factor between the electromagnetic transponder and the terminal to a selected optimum coupling factor, the selected optimum coupling factor based on a first resistive load value; storing the calculated first ratio; controlling a variable capacitance circuit of the terminal with control information generated by a phase interval detection circuit, the phase interval detection circuit arranged to receive data representative of current flowing through a measurement element of the terminal, the current flowing through the measurement element of the terminal corresponding to a current coupling factor between the electromagnetic transponder and the terminal; calculating by the terminal a current ratio relating the current coupling factor between the electromagnetic transponder and the terminal to the selected optimum coupling factor; comparing by the terminal said current ratio with said first ratio; and controlling at least one output data element according to said comparison. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A terminal arranged for communication with an electromagnetic transponder, comprising:
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a control circuit; an antenna circuit; a modulator to encode data in a high frequency signal under direction of the control circuit, the data communicated via the antenna for reception by the electromagnetic transponder; and a phase regulation feedback circuit arranged to provide measurement information representative of a coupling factor between the terminal and the electromagnetic transponder, the phase regulation feedback circuit including; a variable capacitance circuit series coupled to the antenna; a measurement element series coupled to the variable capacitance; and a phase interval detection circuit arranged to receive data representative of current flowing through the measurement element, the phase interval detection circuit arranged to provide control information to the variable capacitance; wherein the terminal is arranged to; iteratively calculate a ratio relating the coupling factor to a reference coupling factor, the reference coupling factor based on a reference load value; store each calculated ratio; compare a current ratio with an earlier calculated ratio; and control an output data element according to said comparison. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A phase regulation feedback circuit arranged to provide measurement information representative of a coupling factor between a terminal and an electromagnetic transponder, comprising:
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a variable capacitance element coupleable to a control circuit and an antenna circuit; a measurement element series coupled to the variable capacitance element; and a phase interval detection circuit arranged to receive data representative of current flowing through the measurement element, the current flowing through the element representative of the coupling factor, the phase interval detection circuit further arranged to direct control information to the variable capacitance element based on a calculated ratio relating the coupling factor to a reference coupling factor. - View Dependent Claims (17, 18, 19)
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Specification