| 摘要 |
An optical repeater provided in an up line (66a) and a down line (66b), the optical repeater includes a first circuit (1, 60a) related to the up line, and a second circuit (2, 60b) related to the down line. Each circuit includes an optical receive/decision circuit (1, 2), a command extraction circuit (61a, 61b), a command detection circuit (63a, 63b), a command switch (64a, 64b) and a supervisory circuit (65a, 65b). Each circuit also includes a noise component processing circuit (62a, SWa, 62b, SWb) which extracts, from the electrical signal, a noise component within a predetermined frequency range excluding a frequency (f1) of the command signal and determines whether or not the optical signal is input to the optical receive/decision circuit on the basis of the noise component and which prevents the noise component passing through the command extracting circuit from being directly applied to the command detecting circuit when it is determined that no the optical input is input to the optical receive/decision circuit. Each circuit further includes an output circuit which converts the data signal and a supervisory signal into an optical output which is transferred to a corresponding one of the up line and the down line. |
