Abstract: A synchronization system maintains the accuracy of time frame synchronization in an earth satellite time division multiple access system. Two metric patterns are provided for giving synchronization accuracy. The system selects one pattern, compares accuracy with threshold values. If the comparison shows less than threshold accuracy, the system switches to the other pattern.

Abstract: In order to implement burst acquisition control of reference stations over a traffic terminal(s) in the TDMA system, the reference station opens a synchronization window at the nominal position of the traffic terminal. The reference station checks to determine if a burst transmitted from the traffic terminal is detected within said synchronization window. If the burst is detected within said synchronization window, then the burst acquisition control is omitted. Otherwise, the burst acquisition control is implemented.

Abstract: A supervising and controlling system for a TDMA equipment in a TDMA station designates one of two control memories in the TDMA equipment as a spare one with the other as operating one by a memory selection signal from a supervisory and control apparatus. The content of the spare memory is periodically verified by the significant control data from the control apparatus. When non-coincidence is detected by the verification, the significant control data is transmitted to the TDMA equipment and is written into the spare control memory without interfering with other stations.Two similar TDMA equipments are provided in the station and controlled by the control apparatus in the similar manner. One of the equipments can be selectively used as an operating one by equipment selection signals from the control apparatus.