| 摘要 |
PURPOSE:To make easy the identification whether failed parts in optical communication is at optical fiber or transmission and reception circuit, by means of the input to the reception circuit for the photo detector without optical fiber for the transmission side laser light. CONSTITUTION:When the switch 10 is selected to the position a, the information from the transmission circuit 1 is converted into optical signal with the laser 2 and fed via the optical fiber 3 and received at the reception circuit 7 from the photo detector 5 and the amplifier 6. When the switch 10 is selected to the position b, the backward optical output from the laser 2 is directly or via the half mirror branched and picked up to the optical output for monitor. This is fed to the monitoring photo detector 8 and inputted to the reception circuit 7 via the amplifying circuit 9. By inspecting the communication state in two paths as mentioned above, the discovery of failed parts can be made easy. |
