Reader/writer and communication method thereof
First Claim
1. A reader/writer performing radio communication with a radio communication terminal in close proximity thereto, comprising:
- an antenna for transmitting a carrier wave of a predetermined frequency and receiving a composite wave of said carrier wave and a modulated signal of a signal having the frequency identical to that of said carrier wave transmitted from said radio communication terminal;
a demodulating unit for demodulating the composite wave received by said antenna;
a judging unit for judging whether a null state has occurred when said radio communication terminal is in close proximity; and
a carrier-wave control unit having an auxiliary antenna provided in the proximity of said antenna for reducing a component of said carrier wave input into said demodulating unit by wirelessly transmitting a signal of a reverse phase to said carrier wave from the auxiliary antenna when said judging unit judges that the null state has occurred.
4 Assignments
0 Petitions
Accused Products
Abstract
A reader/writer is provided. The reader/writer performing radio communication with a radio communication terminal in close proximity thereto, includes: an antenna which transmits a carrier wave of a predetermined frequency and which receives a composite wave of the carrier wave and a modulated signal of the carrier wave transmitted from the radio communication terminal; a demodulating unit which demodulates the composite wave received by the antenna; a judging unit which judges whether or not it is difficult to detect a modulated component included in the composite wave received by the antenna when the radio communication terminal is in close proximity; and a carrier-wave control unit which reduces a component of the carrier wave input into the demodulating unit when the judging unit judges that it is difficult to detect the modulated component.
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Citations
6 Claims
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1. A reader/writer performing radio communication with a radio communication terminal in close proximity thereto, comprising:
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an antenna for transmitting a carrier wave of a predetermined frequency and receiving a composite wave of said carrier wave and a modulated signal of a signal having the frequency identical to that of said carrier wave transmitted from said radio communication terminal; a demodulating unit for demodulating the composite wave received by said antenna; a judging unit for judging whether a null state has occurred when said radio communication terminal is in close proximity; and a carrier-wave control unit having an auxiliary antenna provided in the proximity of said antenna for reducing a component of said carrier wave input into said demodulating unit by wirelessly transmitting a signal of a reverse phase to said carrier wave from the auxiliary antenna when said judging unit judges that the null state has occurred. - View Dependent Claims (2, 3)
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4. A communication method of a reader/writer performing radio communication with a radio communication terminal in close proximity thereto, comprising:
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transmitting a carrier wave of a predetermined frequency; receiving a composite wave of said carrier wave and a modulated signal of said carrier wave transmitted from said radio communication terminal; demodulating said composite wave received; judging whether a null state has occurred when said radio communication terminal is in close proximity; and wirelessly transmitting a signal of a reverse phase to said carrier wave from an auxiliary antenna when judged that the null state has occurred.
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5. A reader/writer performing radio communication with a radio communication terminal in close proximity thereto, comprising:
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an antenna for transmitting a carrier wave of a predetermined frequency and receiving a composite wave of said carrier wave and an amplitude-modulated signal of a signal having the frequency identical to that of said carrier wave transmitted from said radio communication terminal; a demodulating unit for demodulating the composite wave received by said antenna; a judging unit having a resistor for judging whether a null state has occurred based on voltages at both ends of a resistor to which said composite wave received is supplied when said radio communication terminal is in close proximity; and a carrier-wave control unit for reducing a component of said carrier wave input into said demodulating unit when said judging unit judges that the null state has occurred. - View Dependent Claims (6)
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Specification