RFID transceiver device
First Claim
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1. An RFID transceiver device comprising:
- a local oscillation circuit that generates a local oscillation signal;
a demodulation circuit that demodulates a reception signal using the frequency of the local oscillation signal output from said local oscillation circuit;
a transmission circuit that modulates, amplifies and transmits a local oscillation signal output from said local oscillation circuit;
a duplexer that supplies to a transceiving antenna the transmission signal from said transmission circuit and branches the reception signal received by said transceiving antenna to said demodulation circuit; and
a delay circuit between said local oscillation circuit and said demodulation circuit, whereinthe amount of delay of said delay circuit is set to a magnitude corresponding to the path difference between the path of the leakage, via said duplexer into said demodulation circuit, of the transmission signal that is output from said local oscillation circuit for transmission, and the path of direct input of the local oscillation signal from said local oscillation circuit to said demodulation circuit.
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Abstract
An RFID transceiver device is capable of high sensitivity reception, by the reduction of noise, irrespective of the distance to the tag. The RFID transceiver device includes a delay circuit between a local oscillation circuit and a demodulation circuit, wherein the amount of delay of the delay circuit is set to a magnitude corresponding to the path difference between the path of leakage, via a duplexer into the demodulation circuit, of transmission signal output from the local oscillation circuit for transmission, and the path of direct input of the local oscillation signal from the local oscillation circuit to the demodulation circuit.
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Citations
5 Claims
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1. An RFID transceiver device comprising:
a local oscillation circuit that generates a local oscillation signal; a demodulation circuit that demodulates a reception signal using the frequency of the local oscillation signal output from said local oscillation circuit; a transmission circuit that modulates, amplifies and transmits a local oscillation signal output from said local oscillation circuit; a duplexer that supplies to a transceiving antenna the transmission signal from said transmission circuit and branches the reception signal received by said transceiving antenna to said demodulation circuit; and a delay circuit between said local oscillation circuit and said demodulation circuit, wherein the amount of delay of said delay circuit is set to a magnitude corresponding to the path difference between the path of the leakage, via said duplexer into said demodulation circuit, of the transmission signal that is output from said local oscillation circuit for transmission, and the path of direct input of the local oscillation signal from said local oscillation circuit to said demodulation circuit. - View Dependent Claims (2, 4, 5)
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3. An RFID transceiver device comprising:
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a local oscillation circuit that generates a local oscillation signal; a demodulation circuit that demodulates a reception signal using the frequency of the local oscillation signal output from said local oscillation circuit; a modulation circuit that modulates the local oscillation signal output from said local oscillation circuit; a duplexer that supplies to a transceiving antenna the transmission signal output from said modulation circuit and branches the reception signal received by said transceiving antenna to said demodulation circuit; and a path for supplying the transmission signal output from said modulation circuit as the local oscillation signal to said demodulation circuit, wherein the amount of delay on said path and the amount of delay on the path of the leakage of the transmitted carrier signal that is input to said demodulation circuit through said duplexer are set to the same magnitude.
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Specification