Carrier frequency variation for device detection in near-field communications
First Claim
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1. A method of operating a near-field communications (NFC) device comprising an NFC antenna, a matching network coupled to the NFC antenna, and a transmitter coupled to the matching network, the method comprising:
- applying a signal from the transmitter to the matching network;
varying a frequency of the signal;
measuring a parameter while varying the frequency of the signal;
identifying a first peak value of the parameter;
comparing the first peak value to a threshold to determine whether another NFC device is present; and
initiating a communication protocol with the other NFC device in response to a determination that the first peak value satisfies the threshold.
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Abstract
A near-field communications (NFC) device includes an NFC antenna, a matching network coupled to the NFC antenna, and a transmitter coupled to the matching network. The transmitter applies a signal to the matching network and varies a frequency of the signal. A parameter is measured while varying the frequency of the signal. A peak value of the parameter is identified and compared to a threshold. A communication protocol is initiated in response to a determination that the peak value satisfies the threshold.
22 Citations
22 Claims
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1. A method of operating a near-field communications (NFC) device comprising an NFC antenna, a matching network coupled to the NFC antenna, and a transmitter coupled to the matching network, the method comprising:
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applying a signal from the transmitter to the matching network; varying a frequency of the signal; measuring a parameter while varying the frequency of the signal; identifying a first peak value of the parameter; comparing the first peak value to a threshold to determine whether another NFC device is present; and initiating a communication protocol with the other NFC device in response to a determination that the first peak value satisfies the threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A near-field communications (NFC) device, comprising:
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an NFC antenna; a matching network coupled to the NFC antenna; a transmitter, coupled to the matching network, to provide a signal to the matching network; one or more processors; and memory storing one or more programs configured to be executed by the one or more processors, the one or more programs comprising; instructions to vary a frequency of the signal; instructions to measure a parameter while varying the frequency of the signal; instructions to identify a first peak value of the parameter; instructions to compare the first peak value to a threshold to determine whether another NFC device is present; and instructions to initiate a communication protocol with the other NFC device in response to a determination that the first peak value satisfies the threshold. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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22. A near-field communications (NFC) device, comprising:
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an NFC antenna; a matching network coupled to the NFC antenna; a transmitter, coupled to the matching network, to provide a signal to the matching network and to vary a frequency of the signal; means for measuring a parameter while varying the frequency of the signal; means for identifying a first peak value of the parameter; means for comparing the first peak value to a threshold to determine whether another NFC device is present; and means for initiating a communication protocol with the other NFC device in response to a determination that the first peak value satisfies the threshold.
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Specification