| 摘要 |
PROBLEM TO BE SOLVED: To prevent a long time interruption of services by line disconnection when a changeover of a transmission line is executed by absorbing on a parent station device side a transmission delay time difference by a difference in an optic transmission passage of an optic PDS system in which a light transmission and reception part adapts a redundant structure. SOLUTION: On a transmission side, in order to match delay times of 0 system and 1 system, when a transmission timing of a down signal is switched to a transmission line on an Ncmin side in which delay data are small, basing on an Ncmax , in which the delay data are larger, as a reference, the down signal, a delay time difference on the transmission side is adjusted by delaying the down signal for a delay control time Tn /2 at a down delay control part 110 and transmitting it. On a reception side, a transmission is performed, basing on the Ncmax , in which delay data of a transmission timing of plural slave station devices are large, as a reference. Then, when a changeover to a transmission line on the Ncmin side in which the delay data are small is executed, a transfer delay time difference by a difference of a light transmission passage is absorbed on the parent station device side by delaying an up signal for the delay control time Tn /2 at an up delay control part 111 and receiving it. |
