| 摘要 |
PURPOSE:To eliminate overload oscillation, attenuation of a current, distortion of a waveform, etc., and to easily search a laying position of a cable, by supplying a DC current in the direction opposite to a regular feed current, and superposing a low frequency AC current on its DC current. CONSTITUTION:A flow direction of a DC current I' indicated with an arrow Y is a-current, that is to say, a direction opposite to a regular direction. In short, to a Zener diode ZD, the flow is conducted in the conducting direction based on a diode characteristic. As a result, the working resistance becomes about 1-10OMEGA to suppress attenuation of a current to a very small value. Since the flow is conducted in the direction opposite to the regular direction, an amplifier AMP does not become an operating state, an overload phenomenon is not generated, and the casue of deterioration of repeaters R1-Rn is eliminated. The working resistance of the diode ZD is small, almost all AC current that are supplied flow to the diode ZD, a supplied current which is made to flow to the ZD increases, and an AC magnetic field can be formed up to an apogee. In this way, loss on the transmission line can be reduced, and deterioration at a repeating point can be prevented. |
