| 摘要 |
<p>PURPOSE:To suppress the lowering of detection accuracy and increase detectable distance by transmitting the magnetic field output by a transmission means with the same frequency as that of remaining vibration. CONSTITUTION:Near the buried pipe, a resonance part 2 is attached. A probe device 6 is scanned along with the ground surface 7 and when an antenna coil 8 approaches above a marker antenna coil 5, a resonance body 3 starts vibration owing to the excitation signal (magnetic field) transmission part 8a. If a transmission reception switching part 10b switches to the reception part 9a side, the excitation signal from the coil 8b terminates. Just after the termination of the excitation signal, excitation current remains in the excitation part 2 and is input to a coil 8b, received with a reception part 9a and the buried position of the buried pipe 1 is detected. By the way, when there is a shift between the frequency of the output magnetic field and that of the resonance signal 1 received with the reception part 9a, the output frequency of the transmission part 8a is corrected and changed to the same as the resonance frequency.</p> |
