Abstract
Double repetition code exhibits unique properties when combined with precoded generalized minimum-shift keying signals of upto two symbol period pulse duration. It is shown that using two stages of channel encoding, the last being a double repetition code, the code design for such modulation scheme simplifies. Also, it is shown that the nonlinear continuous-phase frequency-shift keying modulator can be replaced by a simple linear I-Q modulator to generate the same coded signals. The detection problem for the recovery of the symbols sequence from the decision variables is shown to be one corresponding to memoryless modulation, avoiding the use of the maximum likelihood sequence detection.