| 摘要 |
PURPOSE:To aways acquire the hourly synchronization between a master timepiece in a master station and slave timepieces in slave stations without affecting the action of remote supervisory and control by switching a circuit to a backup transmission line for a remote supervisory and controlling equipment and inserting a time code generator for hourly synchronization and a time code decoder. CONSTITUTION:In the master station 0 an arithmetic processing circuit CPU0 isolates switching circuits CT01, CT02,... from code transmission circuits S01, S02,... through an output circuit DO02 at a time when the circuit CPU0 completes the transmission of changeover control commands for receiving a time code(at most an estimation of 0.5 sec is sufficient in consideration of different signal transmission speeds). The isolated circuits CT01,... are connected to the time code generator TG. After the switching, time codes that the time code generator TG outputs are modulated by modulator circuits M01, M02,... and they are transmitted to the slave stations 1, 2... through down lines L12d, L22d,... in the backup transmission line. Since in the slave station 1 the switching circuit CT1 is connected to the side of the time code decoder TD1, the output of a demodulator circuit D12 is handed to the time code decoder TD1, thereby receiving the time code. |
