发明授权
US6052055A Portable electronic object for remote information exchange 有权
便携式电子对象进行远程信息交换

Portable electronic object for remote information exchange
摘要:
A memory card, capable of remotely exchanging information with a terminal by modulating a magnetic field generated by said terminal, includes a voltage limiter (LMT) with an input terminal (BE) for receiving, during the transmission of information between the terminal and the card, an amplitude modulated voltage (VNR) with a time-varying average voltage level (NM). A primary transistor (TZ1) is connected between the input terminal and ground. Diodes (D1. . . DN) are series connected between the input terminal (BE) and ground and between the input terminal (BE) and the gate of the primary transistor (TZ1), wherein the threshold voltages of the diodes and primary transistor define a limit value for the input voltage. A capacitor (C) is connected between the primary transistor gate and ground. A resistive array (RD, TR) is connected between the capacitor and ground, and forms, with the capacitor, a resistive/capacitive array with a time constant selected so as to be comprised between the time variation period of the average voltage level and the amplitude modulation period.
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