| 摘要 |
PURPOSE:To reduce the cost of the facilities of earth stations having various speeds of transmission to one repeater provided to a satellite by sending plural frame reference bursts while one of earth stations as a reference station for synchronization. CONSTITUTION:One of eart stations is regarded as the reference station for synchronization. This reference station has a modulator for frame reference bursts FRB corresponding to respective transmission speeds. Namely, FRB-H, FRB-M, and FRB-L are bursts FRB corresponding to a high- speed, an intermediate-speed, and a low-speed network group. Therefore, each earth station synchronizes with the FRBs with respective transmission speeds to establish the whole frame synchronism. Thus, each earth station employs facilities of only scale enough for transmission capacity, so the cost is reduced. |
