| 摘要 |
PURPOSE:To eliminate occurrence of momentary interruption by implementing alternate control between a main reference station being a time reference of a time division multiple access frame and a sub reference station while keeping a relative time location of each reference synchronization burst signal. CONSTITUTION:A carrier recovery signal 11, a clock recovery signal 12, a synchronization word 13, a reference station status control signal 14, and a synchronization control and line control signal 15 are located in this order in a reference synchronization burst signal 10 used for reference station alternate control, and a code '0' is used in the main reference station state and a code '1' is used in the sub reference station state for the signal 14. When any fault takes place in a 1st reference station 2 being the main reference station at present, the level of the signal 14 in a 1st reference synchronization burst signal 21 changes from '0' into '1' and the level of the signal 14 in a 2nd reference synchronization burst signal 22 changes from '1' into '0' to change the state of the reference station. Then a signal 22 being a time reference signal of a time division multiple access frame is outputted from a 2nd reference station 3 being the main reference station. |
