| 摘要 |
Embodiments of the present invention relates to a vehicle transponder comprising an active radio unit, an antenna, a wake-up unit and a power directing means which has a first port, a second port and a third port, where the power directing means is arranged to direct power from the first port to the second port and/or the third port. The antenna is connected to the first port and the second port is connected to the radio unit. Furthermore, the third port is connected both to a power detection port at the radio unit and to the wake-up unit, such that during a first mode of operation, a part of a signal that is transmitted from the radio unit to the antenna is coupled from the second port to the third port and further fed to the power detection port. |
