Suboptimal Maximum Likelihood Timing Estimator for a PCM Regenerative Repeater

This paper introduces a modified likelihood function and then provides the suboptimal maximum likelihood (SML) timing estimator which is applicable to PCM regenerative repeaters because of its structural simplicity. Since the SML timing estimator tracks a difference waveform balancing point, as opposed to its conventional maximum likelihood (ML) counterpart, which tracks a derivative waveform zero-crossing point, its performance is rather immune against channel phase distortion. Analyses and experiments are also presented to validate the SML timing estimator for timing extraction from a band-limited PAM signal.