The design of asymmetric coded frequency/phase modulation (FPM) is discusse
d. Designs for optimum asymmetric 2FSK/4PSK, 2FSK/8PSK and 2FSK/16PSK modul
ation schemes are derived and the effect of modulation index is studied. It
is shown that an additional gain of 1.2-2.6dB can be achieved by using opt
imised asymmetric modulation over that of a symmetric scheme.