MULTILEVEL SCPC SYSTEM DESIGN.

A method of assigning carrier levels in an SCPC system with mixed earth station G/Ts is developed which optimizes system performance for uniformly spaced and randomly assigned carrier frequencies. The optimum transponder backoff is shown to be identical to that for a system of uniform carriers in which the (common) earth station (G/T)** minus **1 is a weighted average of the different (G/T)** minus **1 values in the mixed system. With the transponder backoff determined, the carrier level to be transmitted to each station type is expressed simply in terms of the station G/T.