Non-contact IC card, terminal for use with the non-contact IC card and non-contact IC card system having the non-contact IC card and the terminal
First Claim
1. A non-contact IC card comprising:
- receiving means including first and second receiving sections wherein the first receiving section has a first detection threshold for detecting a received signal having a strength exceeding the first detection threshold, the second receiving section has a second detection threshold for detecting a received signal having a strength exceeding the second detection threshold, and the first detection threshold is higher than the second detection threshold;
a demodulation circuit connected to the receiving means for demodulating a received signal detected by one of the first and second receiving sections and producing demodulated signals;
selection means for selectively connecting the first and second receiving sections to the demodulation circuit; and
control means for controlling data processing by the non-contact IC card and for controlling the selection means, the control means receiving the demodulated signals from the demodulation circuit and controlling the selection means to connect the first receiving section to the demodulation circuit and, upon detection of a trigger signal by the first receiving section, disconnecting the first receiving section and connecting the second receiving section for detecting a data signal including data for processing by the control means.
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Accused Products
Abstract
A non-contact IC card, a non-contact IC card terminal and a non-contact IC card system for performing data communication between the IC card and the terminal by using electromagnetic waves are arranged so that the IC card can reliably receive data transmitted from the terminal once the IC card is started up by a startup signal from the terminal. A selection circuit, under the control of a CPU selects a receiving amplifier having a smaller amplification factor in a startup step for receiving the startup signal and a receiving amplifier having a larger amplification factor in a data communication step for exchanging data signals. The sensitivity with which the data signal is received is thereby increased relative to the sensitivity with which data signals are received.
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Citations
17 Claims
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1. A non-contact IC card comprising:
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receiving means including first and second receiving sections wherein the first receiving section has a first detection threshold for detecting a received signal having a strength exceeding the first detection threshold, the second receiving section has a second detection threshold for detecting a received signal having a strength exceeding the second detection threshold, and the first detection threshold is higher than the second detection threshold; a demodulation circuit connected to the receiving means for demodulating a received signal detected by one of the first and second receiving sections and producing demodulated signals; selection means for selectively connecting the first and second receiving sections to the demodulation circuit; and control means for controlling data processing by the non-contact IC card and for controlling the selection means, the control means receiving the demodulated signals from the demodulation circuit and controlling the selection means to connect the first receiving section to the demodulation circuit and, upon detection of a trigger signal by the first receiving section, disconnecting the first receiving section and connecting the second receiving section for detecting a data signal including data for processing by the control means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A terminal for triggering and exchanging data with a non-contact IC card comprising:
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receiving means for detecting a reply signal from a non-contact IC card in response to a trigger signal transmitted by the terminal and for receiving data signals from the non-contact IC card; a demodulation circuit connected to the receiving means for demodulating reply and data signals received from the non-contact IC card to produce demodulated signals; a modulation circuit for modulating data and trigger signals;
transmitting means including first and second transmitting sections wherein the first transmitting section produces data signal having a first electromagnetic energy, the sound transmitting section produces a trigger signal having a second electromagnetic energy, and the first electromagnetic energy is larger than the second electromagnetic energy;selection means for selectively connecting the first and second transmitting sections to the modulation circuit; and control means for controlling data processing of data signals received from the non-contact IC card and for controlling the selection means, the control means receiving the demodulated signals from the demodulation circuit and controlling the selection means to connect the second transmitting section to the modulation circuit to transmit a trigger signal and, upon detection of a reply signal from an IC card, disconnecting the second transmitting section from the modulation circuit and connecting the first transmitting section to the modulation circuit for transmitting data signals. - View Dependent Claims (10, 12, 13, 14, 15, 16)
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11. The terminal according to claim wherein;
- the first and second transmitting sections include an amplifier for amplifying signals received from the modulation circuit, the amplifier including first and second resistors for changing amplification by the amplifier, the first resistor having a smaller resistance than the second resistor.
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17. A non-contact IC card system comprising:
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a terminal and non-contact IC card wherein the non-contact IC card includes; first receiving means including first and second receiving sections wherein the first receiving section has a first detection threshold for detecting a received signal having a strength exceeding the first detection threshold, the second receiving section has a second detection threshold for detecting a received signal having a strength exceeding the second detection threshold, and the first detection threshold is higher than the second detection threshold; a first demodulation circuit connected to the first receiving means for demodulating a received signal detected by one of the first and second receiving sections and producing first demodulated received signals; first selection means for selectively connecting the first and second receiving sections to the first demodulation circuit; and first control means for controlling data processing by the non-contact IC card and for controlling the first selection means, the first control means receiving the demodulated received signals from the first demodulation circuit and controlling the first selection means to connect the first receiving section to the first demodulation circuit and, upon detection of a trigger signal by the first receiving section, disconnecting the first receiving section and connecting the second receiving section for detecting a data signal including data for processing by the non-contact IC card; an oscillator for producing an oscillation signal; a first modulation circuit for modulating the oscillation signal to produce first modulated signals; and a first transmitting antenna connected to the first modulation circuit for transmitting the first modulated signals wherein, upon detection of a trigger signal by the first receiving section, the control means connects the oscillation signal to the first modulation circuit for generation of a reply signal supplied to the transmitting antenna for transmission to a terminal generating the trigger and data signals; and the terminal includes; second receiving means for detecting a reply signal from the non-contact IC card in response to a trigger signal transmitted by the terminal and for receiving data signals from the non-contact IC card; a second demodulation circuit connected to the second receiving means for demodulating reply and data signals received from the non-contact IC card and producing second demodulated received signals; a second modulation circuit for modulating data and trigger signals; transmitting means including first and second transmitting sections wherein the first transmitting section produces data signals having a first electromagnetic energy, the second transmitting section produces a trigger signal having a second electromagnetic energy, and the first electromagnetic energy is larger than the second electromagnetic energy; second selection means for selectively connecting the first and second transmitting sections to the second modulation circuit; and second control means for controlling data processing of data signals received from the non-contact IC card and for controlling the second selection means, the second control means receiving the second demodulated received signals from the second demodulation circuit and controlling the second selection means to connect the second transmitting section to the second modulation circuit to transmit a trigger signal and, upon detection of a reply signal from an IC card, disconnecting the second transmitting section from the second modulation circuit and connecting the first transmitting section to the second modulation circuit for transmitting data signals.
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Specification