| 摘要 |
<p>PURPOSE:To decrease the magnetic field intensity based on the noise signal impressed to a detecting coil and to improve S/N and reliability by inserting the detecting coil into a conductor ring and disposing the coil in this state to face the magnetic field generated in the object placed underground. CONSTITUTION:An AC current is supplied from an oscillator 8 which is a power source to the object A placed underground and the output of the oscillator 8 is introduced to a phase detector 7c of an inference circuit section 7. Further, the detecting coil 7 of the fluxmeter 1 is inserted into the conductor ring 9 consisting of a normal conductor and is so disposed in this state that the ring 9 is opened at top and bottom. A minus current is passed in the coil 2 by the incoming of the external magnetic flux and this magnetic flux is detected by the fluxmeter 1. The magnetic field generated by the ring 9 eventually decreases the magnetic flux in the ring 9 when the magnetic flux having the frequency to the extent of allowing the flow of a stationary induced current is impressed to the ring 9 at this time. The intensity of the magnetic field based on the noise impressed on the coil 2 is then decreased and the noise quantity included in the output of the fluxmeter 1 is decreased.</p> |
