| 摘要 |
PURPOSE:To freely constitute and change groups of satellite earth stations, by controlling frequency of time division multiplex satellite transmission lines used by each satellite earth station from a central satellite earth station. CONSTITUTION:Frequencies of time division multiplex satellite transmission lines to be used by satellite earth stations 1,2...n, are stored in memories of a central satellite earth station C in advance. At the initial set or at a failure taken place, each satellite earth station uses a common frequency f0 and gives inquiry to the said central satellite earth station C via a satellite S. The station C receives the signal in the said frequency f0, then informs a control signal including the frequency number to be used by each satellite station by using a frequency f0'. In changing a frequency used at present by a certain satellite earth station, the content of memory in the said station C is changed and transmits the frequency change signal to the satellite earth station by using the frequency in use. |
