| 摘要 |
PURPOSE:To obtain an optical receiver detecting the generation of an abnormal signal at the transient state caused in quickly attaching/detaching an optical transmission line by counting a pulse signal outputted from a photodetector and outputting a detection signal when the count reaches a predetermined value. CONSTITUTION:A photo diode 1 as a photodetector is connected to an optical fiber by an optical connector. The photodetector 1 converts an optical signal sent through the optical fiber into an electric signal, which is fed to an amplifier 2, which amplifies the signal and supplies the result to a comparator circuit 3. The comparator circuit 3 compares the output of the amplifier 2 with a predetermined threshold voltage to apply the threshold discrimination. In attaching/detaching an optical transmission line, the pulse signal outputted from the photodetector 1 is counted and when the count reaches a predetermined value, an attaching/detaching detection means 7 outputs a detection signal. Thus, the attachment/detachment of the optical coupling is momentarily sensed and the occurrence of an accident resulting in injury or death due to malfunction is evaded. |
