| 摘要 |
<p>The present invention relates to a vehicle transponder (1) comprising an active radio unit (8), an antenna (2), a wake-up unit (9) and a power directing means (3, 21, 22) which has a first port (4, 4', 4"), a second port (5, 5', 5") and a third port (6, 6', 6"), where the power directing means (3, 21, 22) is arranged to direct power from the first port (4, 4', 4") to the second port (5, 5', 5") and/or the third port (6, 6', 6"). The antenna (2) is connected to the first port (4, 4', 4") and the second port (5, 5', 5') is connected to the radio unit (8). Furthermore, the third port (6, 6', 6") is connected both to a power detection port (10) at the radio unit (8) and to the wake-up unit (9), such that during a first mode of operation, a part of a signal that is transmitted from the radio unit (8) to the antenna (2) is coupled from the second port (5, 5', 5") to the third port (6, 6', 6") and further fed to the power detection port (10). The degree of signal that is coupled from the second port (5, 5', 5") to the third port (6, 6', 6") is dependent on the connection properties between said second port (5, 5', 5") and third port (6, 6', 6").</p> |
