| 摘要 |
A card reader is disclosed, which includes at least one low frequency transmission coil, at least one driving circuit, at least one coding circuit, at least one first main processor, at least one radio frequency transceiver circuit and at least one radio frequency antenna; the low frequency transmission coil, the driving circuit, the coding circuit, the first main processor, the radio frequency transceiver circuit and the radio frequency antenna are connected in series, wherein, the low frequency transmission link composed of the low frequency transmission coil, the driving circuit, and the coding circuit works in a frequency below a pre-selected maximal frequency f0 of system non-calibration work. The card reader transmits a preset low frequency alternating magnetic field signal with constant amplitude or constant differential amplitude; the amplitude value of the low frequency alternating magnetic field signal corresponds to a set physical communication distance, the amplitude error of the low frequency alternating magnetic field signal less than a preset error value dR. The card reader enables all mobile terminals with near field communication function to realize swiped transaction such as electronic payment without calibration. |
