| 摘要 |
PROBLEM TO BE SOLVED: To simultaneously realize supply of power or a clock and two-way communication of serial data by only two contacts in a contact type data carrier system. SOLUTION: In a controller 1, an operation voltage Vout is made higher and amplitudes of clock pulse signals CK and ICK are made wider when a transmission signal TS1 is 'L', but the amplitudes are made shorter when the transmission signal TS1 is 'H'. In a data carrier device 2, signals CK and ICK are subjected to full wave rectification into the operation voltage by a rectifying circuit 21, and a reception signal RS2 is extracted by a second signal detection circuit 22. In the device 2, the impedance between contacts A and B is made lower and amplitudes of signals CK and ICK are made shorter when a transmission signal TS2 is 'L', but the amplitudes are made wider when the transmission signal TS2 is 'H'. In the controller 1, the change of the amplitude of the signal ICK is extracted as a reception signal RS1 by a first signal detection circuit 15.
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