| 摘要 |
PURPOSE:To prevent collision between signals by dividing the time to pass a signal transmitted from a station through a star coupler into frames of constant length, and by dividing each frame into channels, and then by fixedly assigning channels to respective stations. CONSTITUTION:One frame of star coupler 9 is multiplexed into four in time-division mode. Further, it is wavelength-multiplexed by three wavelengths and composed of 12 channels 1-1-4-3. Then, those channels are fixedly assigned to stations S1-S4; for example, S1 has channel number 1-1, S2 2-2.... A received signal is branched by a branching filter into lambda1, lambda2 and lambda3, which are led to reception processing circuit 15. Further, a signal transmitted from the transmission processing part is applied to light transmitters 18, 19 and 20 which outputs optical signals of lambda1, lambda2 and lambda3 and a signal is composed by synthesizer 21 and sent to transmission line 10. |
