| 摘要 |
PROBLEM TO BE SOLVED: To attain a high withstand voltage between an input and an output circuits simply by setting a light-emitting and a light-detecting elements at end faces of an optical fiber to be integrally united with the optical fiber and using the unit. SOLUTION: An amplification signal from an amplification circuit 29 is supplied to a voltage-frequency conversion circuit (V/F) 30. A measurement signal, i.e., voltage signal is converted to a frequency signal and an output signal is supplied to a light- emitting element 31 such as a light-emitting diode or the like constituting an electooptic conversion element (E/O). The light from the light-emitting element 31 is converted to an electric signal by a light-detecting element 33 constituting an optoelectric conversion element (O/E) set at the side of an output circuit 26 via an optical fiber 32. An optical signal detected at the light-detecting element 32 is supplied to a frequency- voltage conversion circuit (F/V) 34 and converted to a voltage signal. Further, a control signal from a control part 42 is converted to an optical signal via a light-emitting element 44 of an E/O 43 and transmitted to a light-detecting element 46 of an O/E 47 via an optical fiber 45. The optical fiber of a length of approximately 4-5 cm is used, so that between an input and an output circuits can be easily turned to withstand high voltages. |
