| 摘要 |
PURPOSE:To execute communication between terminal stations by providing an optical branch to an optical fiber near a star coupler and a delay circuit at each terminal station to detect separately only signals of other stations even if the signals collide with each other. CONSTITUTION:A preamble signal 10 passes through an optical fiber 3-1-1, and is branched at an optical branch 4-1-1, one is fed to an optical fiber 3-1-2 via a delay circuit 5-1, and the other is divided by the star coupler 2 and returned again to the optical fiber 3-1-2 of the own station. The waveform of the transmitted preamble signal 10 returned via the optical fiber 3-1-2 is received as a flat DC signal as shown by 11 in Fig. 2. Since the own station detects separately only the signals of the other stations even when the other stations transmit their signals and collision takes place, because the preamble transmission signal of the own station is detected as a DC component when the signal is returned to the own station in such a way, accordingly the collision is detected. |
