| 摘要 |
PURPOSE:To reduce the influence of an up direction signal noise by controlling the opening/closing of a switch part when detecting intermodulation distortion by a distortion detecting part. CONSTITUTION:When a terminator is connected to an unused distribution terminal 11, the intermodulation distortion generated at a constant frequency interval by a transmission signal generated from imperfect connection state between metal is detected, and a circuit part 13 which controls a switch circuit 7 to bracket a main line system from a distribution system is comprised. Therefore, when the intermodulation distortion at the constant frequency interval generation from the imperfect connection state between the metal by the terminator connected to the unrequired distribution terminal 11, the switch circuit 7 is immediately controlled, and the bracketing of the main line system from the distribution system can be performed. Thereby, it is possible to minimize the influence of the up signal noise on a main line by the intermodulation distortion. |
