| 摘要 |
The invention discloses a device (5, 6) for transmitting and receiving digital data by electromagnetic induction, comprising a coil (LR), a circuit (10, 40) for limiting a tension induced (Vc) in the coil (LR), switching on when the induced tension is higher than a threshold (VD), demodulating means (20, 20') for receiving the data and, for transmitting the data, and means (IMT, 30, 40) for causing the coil (LR) to fluctuate. The limiter circuit (10, 40) of the invention comprises means (D1-D5, T3) for adjusting the switching threshold (VD) of the limiter circuit at a low level (VDa) during the reception of data and at a high level (VDb) during the transmission of data, and the demodulating means comprise a current demodulator (20) arranged for demodulating the amplitude of a limiting current (Ip) occurring when the limiter circuit is switched on. The invention is useful for contactless chip card and for electronic labels. |
