| 摘要 |
PURPOSE:To measure the distance to a rupture point, etc., accurately at any time by calculating the time difference between the pulse transmission time of an ultrasonic wave and the reception time of its reflected wave. CONSTITUTION:A timing signal outputted from a timing circuit 11 is transmitted from one terminal of an optical fiber cable 7 to be measured through a high-frequency signal driving circuit 2, directional coupler 3, matching circuit 4, transducer 5, and connector 6. If these is a rupture point on the cable 7, a reflected wave is generated at this rupture point, and this reflected wave is passed through the connector 6, transducer 5, circuit 4, and coupler 3, amplified 8, and inputted to an arithmetic circuit 9. A high-frequency signal outputted from the circuit 2 is inputted to the circuit 9, and the distance to the rupture point is computed 9 from the time difference between the high-frequency signal and high- frequency signal of the reflected wave reflected at the rupture point and the second velocity in the optical fiber and displayed on a display device 10. Thus, the distance to the rupture point is measured accurately all the time. |
