| 摘要 |
PURPOSE: To provide simple design and a reasonable cost and also to eliminate the use of an optical switch by providing an optical fiber coupler, cancelling, amplifying and reproduction means and a delay means. CONSTITUTION: A transmission channel and a reception channel are connected to one optical transmission medium ST, a high level crosstalk is provided between ports connected to the transmission channel and the reception channel and the optical fiber coupler CFA for generating an echo signal EC in the reception channel from a test signal which is transmitted to the transmission channel during a transmission period is provided. The cancelling, amplifying and reproducing means OEA and REG for cancelling the transmission of the echo signal EC of the transmission channel when a data signal is transmitted to the optical transmission medium ST, amplifying the echo signal EC when the test signal is transmitted to the transmission channel and executing reproduction into an amplified echo signal are provided. The delay means RE for delaying the amplified echo signal and transmitting it to the receiving means of a line device in the reception period of half-duplex transmission is provided. Thus, simple design and the reasonable cost are provided and also the optical switch is not used. |
