DIGITAL COMMUNICATION SYSTEM EMPLOYING CARRIER PHASE SHIFT

摘要

A digital communication system is disclosed, in which digital information is represented by a quaternary information symbol (11, 01, 00, 10) and double step phase shift leach step being represented by .pi./4, 3.pi./4, 5.pi./4 or 7.pi. /4), is performed per 1/2 time slot in correspondence to each information symbol, so that the number of phase shifts per unit time in the case of identical transmission rates can be decreased to 1/2, as compared with a .DELTA..theta./2 DSK system, and expansion of the bandwidth can be decreased to 1/2.