| 摘要 |
PURPOSE:To miniaturize a repeater by sending pieces of fault monitoring information to a monitor station through one interposing line successively. CONSTITUTION:A current flowing through a laser diode is converted by a resistance R into a voltage V1, which is detected by a comparator 12. When the laser diode 12 varies, the detected voltage changes from V1 to V1'. When an optical PCM repeater is normal, a V2 is applied to a terminal 15 and when not, a V3 is inputted. The V3 is inputted to a transistor (TR) 17 as information with top priority among V1, V1-V1', V2, and V3. When the base voltage of the TR17 is (V1 or V1-V1')+(V2=0)+V3, information on the break of a repeater input signal is detected and when the V1 is normal, a normal state is detected; when it is greater than the V1 and less than the V1', a fault of the laser diode is detected. This detection information is converted by a V.F converter 18 into a frequency, which is transferred to a monitor station 21 via an interposing line 20. Consequently, the repeater is miniaturized. |
