Method for detecting the eventual presence of an object by a contactless reader, and corresponding reader
First Claim
1. A method, comprising:
- transmitting, by an antenna of a first communication device, a magnetic field on a carrier signal comprising a modulated sub-carrier, the modulated sub-carrier being a sub-carrier of the carrier signal modulated by a first data sequence, the modulated sub-carrier being non-detectable by a second communication device;
receiving, on the antenna of the first communication device and in response to the transmitting, a resultant signal;
demodulating, in the first communication device and using a demodulation signal having a frequency of the sub-carrier, the resultant signal, the demodulating generating a second data sequence from the resultant signal;
correlating the first data sequence and the second data sequence; and
detecting a potential presence of the second communication device or an absence of the second communication device based upon a result of the correlating.
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Accused Products
Abstract
A method can be used for detecting a potential presence of an object by a reader capable of mutually communicating via a contactless communications protocol. An antenna of the reader transmits a magnetic field on a carrier signal having a sub-carrier modulated by a first data sequence. The modulated sub-carrier is non-interpretable by the object. The antenna of the reader receives a signal resulting from the transmission. The reader demodulates the sub-carrier of the resulting signal so as to extract a second data sequence from the resulting signal. The first data sequence and second data sequence are correlated and the potential presence or absence of the object is determined based upon the result of the correlating.
15 Citations
20 Claims
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1. A method, comprising:
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transmitting, by an antenna of a first communication device, a magnetic field on a carrier signal comprising a modulated sub-carrier, the modulated sub-carrier being a sub-carrier of the carrier signal modulated by a first data sequence, the modulated sub-carrier being non-detectable by a second communication device; receiving, on the antenna of the first communication device and in response to the transmitting, a resultant signal; demodulating, in the first communication device and using a demodulation signal having a frequency of the sub-carrier, the resultant signal, the demodulating generating a second data sequence from the resultant signal; correlating the first data sequence and the second data sequence; and detecting a potential presence of the second communication device or an absence of the second communication device based upon a result of the correlating. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for detecting a potential presence or an absence of an object by a reader, the method comprising:
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modulating, by the reader, a sub-carrier by a first data sequence to generate a modulated sub-carrier; transmitting, by an antenna of the reader, a magnetic field on a carrier signal having the modulated sub-carrier, the modulated sub-carrier being non-detectable by the object and non-interpretable by the object as being a transmission of information from the reader, wherein the modulated sub-carrier has a frequency corresponding to a reference frequency associated with a contactless communications protocol; receiving, on the antenna of the reader and in response to the transmitting, a resultant signal; demodulating, in the reader, the resultant signal using a demodulation signal having the reference frequency to generate a second data sequence from the resulting signal; correlating the first data sequence with the second data sequence; and detecting the potential presence or the absence of the object based upon a result of the correlating. - View Dependent Claims (11, 12, 13)
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14. A reader, capable of communicating with an object by a contactless communications protocol via an antenna, the reader comprising:
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a modulator configured to modulate a sub-carrier by a first data sequence to generate a modulated sub-carrier, the modulated sub-carrier being non-detectable by the object; a transmitter configured to transmit, via the antenna, a magnetic field on a carrier signal comprising the modulated sub-carrier; a receiver configured to receive a resultant signal on the antenna in response to transmission of the magnetic field; a demodulator configured to demodulate the resultant signal using a demodulation signal having a frequency of the sub-carrier to generate a second data sequence; a correlator configured to perform a correlation between the first data sequence and the second data sequence; and an analysis circuit configured to detect a potential presence of the object or an absence of the object based upon on a result of the correlation. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification