发明名称 |
Modulation, demodulation and antenna coupling circuits used in IC card reading/writing apparatus, and method of supplying power to the IC card |
摘要 |
A modulator used in an IC card reader/writer includes a phase variation detector for detecting a varying point of the phase of a modulated signal, a signal processing circuit for modifying the modulated signal for a half period at the phase varying point to have a frequency and amplitude twice those of the modulated signal, a first Miller integrator for integrating the modified signal to produce a triangular wave signal, and a second Miller integrator for integrating the triangular wave signal to produce a sinusoidal wave signal having a continuous phase. A demodulator used in the reader/writer includes a sync control circuit which controls a carrier sync signal generation circuit thereby to control the phase of a carrier sync signal in response to the discrimination as to whether the carrier sync signal is in lead-phase or lag-phase relative to the signal modulated based on binary phase shift keying (BPSK). A control data signal and non-modulated carrier wave sent from the reader/writer to the IC card are converted into power for use by the IC card.
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申请公布号 |
US5898738(A) |
申请公布日期 |
1999.04.27 |
申请号 |
US19970863044 |
申请日期 |
1997.05.23 |
申请人 |
MITSUBISHI DENKI KABUSHIKI KAISHA |
发明人 |
NAGATA, YOSHISHIGE;TAKAHIRA, KENICHI |
分类号 |
H02J7/00;G06K7/00;G06K7/10;H02J17/00;H04B1/40;H04B7/26;H04L27/18;H04L27/20;H04L27/22;H04L27/233;(IPC1-7):H04L27/14;H04L27/16 |
主分类号 |
H02J7/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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