| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical communication system where a light source of a slave station is not required. <P>SOLUTION: A Manchester coding circuit 20 of a master station 10 encodes downlink data by using a Manchester code. An optical transmitter 22 converts an output of the circuit 20 into an optical signal, and gives its output light to an optical demultiplexer 30 of the slave station 16 via an optical fiber 12. The optical demultiplexer 30 divides the received light into two, applies the one to an optical receiver 32 and the other to an optical modulator 38. The optical receiver 32 converts an output light of the optical demultiplexer 30 into an electric signal, which is fed to a Manchester decoding circuit 34. The circuit 34 extracts a clock from an output of the optical receiver 32 to decode downlink data. A timing adjustment circuit 36 adjusts a timing of uplink data depending on the clock signal from the circuit 34. The optical modulator 38 applies ON/OFF modulation to other output light of the optical demultiplexer 30 according to an output from the circuit 36 and outputs the result to an optical fiber 14. An optical receiver 24 of the master station 10 converts the optical signal from the optical fiber 14 into an electric signal and gives the signal to a demodulation circuit 26. The demodulation circuit 26 demodulates the uplink data from the output of the optical receiver 24. <P>COPYRIGHT: (C)2003,JPO |
