VPSK and VMSK modulation transmit digital audio and video at 15 bits/sec/Hz

Bandwidth efficiencies that have not been possible in the past are now being achieved using variable PSK (VPSK) and variable MSK (VMSK) modulation without the loss of signal power that normally accompanies high bandwidth efficiency methods. Theoretically, these two methods do not lose any signal energy with increasing bandwidth compression. Efficiencies up to 15 bits/sec/Hz are now being achieved in usable hardware with C/N ratios better than that obtainable using FM, BPSK or QPSK. This paper explains how this is accomplished and gives a full mathematical analysis of the method. FM-SCA, VSAT, STL and RPU equipment are now undergoing beta testing prior to FCC Type Acceptance submission. Installation is expected on a large network during 1997.