General structure of symbol-rate decision-directed timing error detectors

The general principle of decision-directed timing error detectors, which can operate at the symbol-rate, is developed, based on a linear combination method. From the fundamental structure of decision-directed timing error detectors, numerous implementations can be derived systematically. These timing error detectors have minimal complexity and optimal performance in the control loop, with respect to minimal jitter, and a timing function with a steep slope. Many timing error detectors known from the literature are special cases which can be derived from the general structure, but they only represent a small fraction of the large number of possible implementations. Optimal synchronizer structures can also be derived with a different method, the maximum likelihood criterion. It is shown that the results of the two approaches coincide in the case of a received signal with high-power additive noise.