| 摘要 |
PURPOSE: A card reader is provided to prevent a card from being approached unnecessarily by inducing a current at an inner coil of a fixed smart card to change a density of a magnetic flux continuously. CONSTITUTION: In a card reader having a signal processor(11) embedding a program fora signal process, a radio frequency module(12) for a radio communication, and a power supplier(14) for applying a driving power, a power controller(15) receives a driving power applied from the power supply part to control a strength of a current in time. A magnetic field generating coil(13) receives a current according to the control of the power controller to generate a density of a magnetic flux varied with time. When the density of the magnetic flux is large, the magnetic field generating coil(13) induces a current at an internal coil of a fixed smart card to drive an integrated circuit chip.
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