| 摘要 |
PROBLEM TO BE SOLVED: To provide a vehicle detector device of fail safe capable of detecting a vehicle in every signal system. SOLUTION: On-vehicle signals Ft1 to Ftn of frequency in accordance with a signal system are transmitted from an on-vehicle antenna 11. A receiving coil 21 of a ground device 2 receives the on-vehicle signals Ft1 to Ftn. A check signal supply circuit 22 supplies check signals Fc1 to Fcn to the receiving coil 21. A level of the check signals Fc1 to Fcn is lower than that of the on-car signals Ft1 to Ftn. A check signal detector circuit 23 includes frequency selector circuits 231 to 23n independent of each other for each on-vehicle signal Ft1 to Ftn and check signal Fc1 to Fcn. The frequency selector circuit 231 to 23n applies suppression to the on-vehicle signals Ft1 to Ftn and the check signals Fc1 to Fcn, to detect the check signals Fc1 to Fcn. |
