Synchronization of noncolocated TV signals in a satellite time-compression multiplexing system

A method of synchronizing uplink earth stations in a time-compression multiplexing system where the stations take turns transmitting TV information in bursts, each lasting for a field duration, is described. The methods simply involve monitoring the radiofrequency bursts sent by other stations already on the air, which enables three stations to synchronize without a centrally controlled master station or clock, without knowledge of one another's baseband video, and without the use of a separate control channel. The only assumption imposed is that the three uplink stations be within the downlink coverage of the satellite. The hardware implementation is simple and can be realized by conventional equipment and digital circuits. A timing analysis is given which shows that the system performance can cover all requirements under a variety of worst-case conditions. Simple procedures for failure recovery are discussed, and a number of practical advantages of the present technique compared with other methods are shown.