| 摘要 |
PROBLEM TO BE SOLVED: To facilitate the transmission of a digital signal by preventing frequency deviations from occurring in local signals of a node and a center. SOLUTION: A local oscillation signal generated by the local oscillator circuit 4 of either a node 1 or a center 2 is made a local oscillation signal of a self- station, also the local oscillation signal is transmitted to an optical fiber 3 between the node 1 and the center 2 as it is or after processing, and the unprocessed or processed local oscillation signal is received by the node 1 and the center 2 of some other station as its local oscillation signal. Either the node 1 or the center 2 uses reference frequency signal to make a local oscillation signal generated by a PLL oscillator circuit 5 as a local oscillation signal of a self-station and transmits the reference frequency signal to the fiber 3 between the node 1 and the center 2 as it is or after processing, and the unprocessed or processed reference frequency signal is received by the mode 1 and the center 2 of the other station to make it a reference frequency signal of its PLL oscillator circuit 6. |
