| 摘要 |
PURPOSE:To obtain a compact communication system which has a high transmission speed and a large capacity and easily discriminates the absence state of a light beam, by generating a clock signal by using a ternary signal generated by a clock signal after converting a transmitted signal into a CMI code. CONSTITUTION:A CMI encoder 1 converts a transmitted signal into a CMI code, which is modulated by a modulating circuit 2 into a ternary signal consisting of positive and negative pulses. In a circuit 3, a light emitting element converts the input into a light signal. A circuit 4 demodulates the received light signal into its positive and negative pulses, and a demodulating circuit 5 converts the CMI code into a pulse signal. Then, a CMI decoder 6 generates a demodulated signal and a demodulated clock signal. On the other hand, a photodetecting circuit 4 finds the average value of a photo-detected signal and on the basis of the average value, a fault of a transmission line is detected by a circuit 7 to output a transmission line monitor signal. |
