Trajectory directed timing recovery

摘要

In a digital demodulator (10) a single sampling moment (28) occurs within each symbol (22). A data estimator (34) identifies a data code and a phase error for each symbol. The data from three symbols (22) are compared to identify whether a phase trajectory is determinate or indeterminate. The phase error from a current symbol is combined with phase trajectory direction data to determine whether a current phase error is in a direction of a next data code or a previous data code. When determinate trajectories are found, phase errors in the direction of a next data code urge the sample moment (28) to occur earlier in the symbols (22) and phase errors in the direction of a previous data code urge the sample moment (28) to occur later in each symbol (22). When indeterminate trajectories are found, substantially no influence is exerted over the timing of the sample moment (28).