| 摘要 |
PROBLEM TO BE SOLVED: To enable a vehicle position to be detected without changing a constant oscillation frequency even in the case of G aspect with the same resonance frequency as the constant oscillation frequency allocated thereto. SOLUTION: Amplification circuits 11 to 14 are made cascade connections and compose a multistage amplification circuit. An on-vehicel piece 2 is provided by a pair of coils 21, 22 connected together facing the ground. The coil 21 is connected to the output side of the multistage amplification circuit, while the coil 22 is connected to the input side of the multistage amplification circuit and compose a return circuit with respect to the multistage amplification circuit. The multistage amplification circuits 11 to 14 and the on-vehicle piece 2 compose an oscillation circuit constantly oscillating at a set constant oscillation frequency fo. A lever judgment circuit 3 is connected to the output side of the amplification circuit 12 positioned more to this side than the last stage of the multistage amplification circuit and outputs a position detection signal S1 corresponding to the output change of the amplification circuit 12. |
