A digital approach to clock recovery in generalized minimum shiftkeying

A method for clock recovery to be used with generalized minimum-shift-keying (MSK) modulations is presented. Attractive features of the method are that it is suited for digital implementation and that its performance is not affected by the carrier-phase recovery process. Clock reference is extracted by passing the sampled baseband waveform through the cascade of a nonlinearity, followed by a digital differentiator whose average output represents the error signal to be employed in a tracking loop. The performance of this scheme is analyzed by means of simulation in steady-state and in transient conditions. Tracking errors are compared with those attained by the well-known De Buda synchronizer and with the Cramer-Rao lower bound