| 摘要 |
<p>PURPOSE:To reduce power consumption by driving light sources at respective measurement points on a time-division basis when measurement is carried out at many points by using an optical fiber sensor. CONSTITUTION:A transmitter 16 generates a reference signal with a specific period. A multiplexer 17 drives light source driving circuits 8 on a time-division basis successively in response to this reference signal. Consequently, LEDs emit light in sequence on a time-division basis, respective physical quantity sensors 1 detect current variations of respective power transmission lines, and photodetecting circuits 9 receive signals indicating the current variations. Further, an optical fiber 5 compensates misdetection caused by variations in the quantities of input light to the physical quantity sensors 1 due to the flawing, bending, etc., of an optical fiber 6, some of received signals of the photodetecting circuits 9 are fed back to the light source driving circuits 9 through a light quantity control circuit 13 to control the DC components of the received signals to constant values. The output of the transmitter 16 and the outputs of the photodetecting circuits 9 are waveform-shaped and then summed up by an adding circuit 10, whose output is processed by a signal processing circuit 11 and displayed on a display circuit 12, so that the accident of a power transmission line is monitored.</p> |
