| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an optical CT applied apparatus (underground line trouble zone determining apparatus and the like) capable of preventing any malfunction caused by stress such as vibration, bending or the like applied to an optical fiber transmission channel contained in an optical CT. <P>SOLUTION: A fundamental wave extracting filter 11 for extracting a fundamental wave component from an output of the optical CT 1, and a system trouble determination processing section 12 for determining the presence or absence of a system trouble based on the extracted fundamental wave component are disposed in the apparatus. Furthermore, a low-frequency wave component which is generated when the stress is applied to the optical fiber transmission channel, and is superimposed on the output of the optical CT, is extracted by using a low-frequency wave extracting filter 13. Then a ratio of the low-frequency wave component/fundamental wave component is obtained by using a content ratio determining section 14. If the ratio is equal to or more than a threshold, the output level of the content ratio determining section is made high. In such the state of stress occurrence, the output of the fundamental wave extracting filter is made large, whereby the system trouble determination processing section has a risk of making an incorrect determination, but the output level of an AND element 16 is kept low, thereby preventing the malfunction. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
