Satellite-communication system employing single-channel/carrier frequency modulation with syllabic companding

The advantages in terms of increased traffic capacity of using a single-channel/carrier companded-frequency modulation satellite system are demonstrated theoretically. These capacity advantages depend critically upon being able to achieve the predicted subjective advantages due to the syllabic compandors. An experimental circuit has been set up and results are presented of objective and subjective tests conducted under carefully controlled laboratory conditions, but simulating conditions typical of a real international telephone circuit. The latter shows that the performance of the companded f.m. system was generally as good as, and frequently superior to, that of an international satellite circuit with a normal noise level of 10000 pWOp. Advantages of the proposed system are demonstrated in both the earth and space segment for global, regional and domestic satellite communications.