| 摘要 |
PROBLEM TO BE SOLVED: To provide a sensor insertable into a narrow space and accurately detecting an electric field value of an electromagnetic wave having an optional wave length including an electromagnetic wave of a low frequency. SOLUTION: This sensor has a pair of hollow detecting conductors 10a and 10b, a signal taking-out coaxial cable 12 for inserting a tip part inside the signal taking-out side detecting conductor 10b, a compensating coaxial cable 14 having a characteristic equal to the signal taking-out coaxial cable 12 and inserted inside the tip side detecting conductor 10a, a differential amplifier 16 for supplying a differential signal of the detecting conductors 10a and 10b to the signal taking-out cable 12 and a reversing amplifier 18 for supplying output to the compensating coaxial cable 14 by reversing the output of the differential amplifier 16, and has a signal analyzing system 60 for simultaneously comparing and displaying signals from two sensors of a subterranean electric field detecting sensor 30 and a ground electric field detecting sensor 40 by analyzing a frequency, and surely captures the electromagnetic wave originated in the ground. COPYRIGHT: (C)2004,JPO
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