Reader-writer terminal device for contactless IC card, communication system and contactless data carrier
First Claim
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1. A reader-writer terminal device for a contactless IC card, comprising:
- a transmission circuit configured to transmit a command to the IC card via an antenna; and
a receiving circuit configured to receive a transmission signal from the IC card, the receiving circuit has an amplifying circuit to amplify a reception signal, lowers an impedance of an impedance element which is disposed in the amplifying circuit and to which the reception signal is applied, and mutes an input signal into the amplifying circuit during a command transmission period in which the transmission circuit transmits the command.
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Abstract
A transmission circuit transmits a command to a contactless IC card. A receiving circuit receives a transmission signal from the IC card and an amplifying circuit in the receiving circuit amplifies the reception signal. An impedance element to which the reception signal is applied is provided at a preliminary stage of the amplifying circuit. The impedance element is controlled so that the impedance thereof is lowered, and an input signal to be input into the amplifying circuit is muted.
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Citations
18 Claims
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1. A reader-writer terminal device for a contactless IC card, comprising:
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a transmission circuit configured to transmit a command to the IC card via an antenna; and a receiving circuit configured to receive a transmission signal from the IC card, the receiving circuit has an amplifying circuit to amplify a reception signal, lowers an impedance of an impedance element which is disposed in the amplifying circuit and to which the reception signal is applied, and mutes an input signal into the amplifying circuit during a command transmission period in which the transmission circuit transmits the command. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A communication system, comprising:
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a contactless IC card configured to receive a command and transmits a response; and a reader-writer terminal device including a transmission circuit configured to transmit the command to the IC card via an antenna, and a receiving circuit configured to receive a transmission signal from the IC card, the receiving circuit has an amplifying circuit to amplify a reception signal, lowers an impedance of an impedance element which is disposed in the amplifying circuit and to which a reception signal is applied, and mutes an input signal into the amplifying circuit during a command transmission period in which the transmission circuit transmits the command. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A contactless data carrier, comprising:
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a reader-writer terminal device including a transmission circuit configured to transmit a command via an antenna, and a receiving circuit configured to receive a reception signal received at the antenna, the receiving circuit has an amplifying circuit to amplify the reception signal, lowers an impedance of an impedance element which is disposed in the amplifying circuit and to which the reception signal is applied, and mutes an input signal into the amplifying circuit during a command transmission period in which the transmission circuit transmits the command; and a contactless IC card which is connected to the antenna, receives the command via the antenna and transmits a response corresponding to the command from the antenna. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification