SPECTRAL-ANALYSIS OF M-ARY PSK MODULATION WITH SMOOTH AND MONOTONIC PHASE VARIATIONS

Computer simulation has shown that smooth and monotonic phase variatio ns in constant envelope M-ary PSK modulation offer a significant reduc tion in the mainlobe width of the trasmitted signal, as compared with alternative conventional PSK modulation schemes. In this paper it is s hown that the above modulation scheme can be considered as a special c ase of CPFSK signals with constant modulation index equal to 1/M. A cl osed-form expression for the power density spectrum is theoretically d erived, and spectral comparisons to conventional PSK schemes with abru pt phase variations are performed. Theoretical results are verified us ing computer simulation, for M equal to 2, 4 and 8.