| 摘要 |
PURPOSE:To shorten the time when an optical transmission line is disabled, by lighting a laser diode after the operation of optical transmitter and receiver becomes normal at a power-on time and extinguishing the laser diode just after power-off. CONSTITUTION:An input signal 1 from the optical transmission line is bisected by an accessory 2, and one is allowed to pass as it is, and the other is sent to a processing part 10 through an optical receiver 4. At the power-on time, a power-on detection signal 13 is sent to a timer 12 and the timer 12 sends an output signal 14 to an AND circuit 17 after the latency time required for the normal operation of an optical transmitter 7 and the optical receiver 4. At the power-off time, the power-off detection signal 13 is outputted to the AND circuit 17 just after power-off detection, and a LD switch circuit 16 is driven by an LD bias driving signal 15 outputted as the result of AND between signals 13 and 14. |
