摘要 |
An information processing device of the invention has an antenna circuit, and a reader/writer device provided with a received signal generating circuit, a microcomputer, a transmitted signal generating circuit, a level detecting circuit, and a D/A converter. The received signal generating circuit is connected to the microcomputer and the antenna circuit, the transmitted signal generating circuit is connected to the microcomputer and the antenna circuit, the D/A converter is connected to the microcomputer and the antenna circuit, the level detecting circuit is connected to the microcomputer and the antenna circuit, and the antenna circuit has an antenna, a resonant capacitor, and a variable capacitor.
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