Fast timing recovery for partial-response signaling systems

An algorithm for fast adjustment of the sample-timing phase in receivers for communication or storage systems using partial-response signaling is presented. For initial adjustment of the timing phase, a known preamble is transmitted. At the beginning of adjustment, previous timing-recovery schemes could occasionally hang up for an extended period of time at the unstable equilibrium point halfway between the desired sampling times. The presented algorithm eliminates the hangup problem by introducing a hysteresis effect that greatly diminishes the probability of reversals of the once chosen direction of timing-phase adjustment. Thus, reliable adjustment of the timing phase with a much shorter preamble is possible. The efficiency of the method is demonstrated by computer simulation results