Title: Synchronization system for time division multiple access relay communications system

• Summary
• Claims
• Description
• View all

Abstract: A Time-Division Multiple Access (TDMA) synchronization system for a satellite relay system is provided by designating one of the ground stations a "Reference" station and arranging for a sinusoidal signal transmitted from the reference station to be received by other ground stations via the satellite and compared with their own sinusoidal synchronization signals after transmission to and from the satellite. The sinusoidal signal from the "Reference" station uses only a small proportion of the bandwidth of a satellite global beam transponder. Most of the traffic is transmitted to one or more spot beam transponders of the satellite. Each station derives from its symbol-rate clock a pulse indicating the start of each TDMA frame and a local synchronization sinusoidal signal at the frame repetition frequency. The phase of this local sinusoidal signal is such that its positive-going zero crossings coincide with the frame-start pulses. These local sinusoidal signals transmitted and received back through the satellite using high-index frequency modulation are compared in phase with the received Reference station sinusoidal signal. The phase difference signal derived from the comparison of the local and reference sinusoidal signals is used to adjust the station's transmit frame timing to achieve synchronization with the reference station frame timing.


Do you think this is a good invention? Vote now: