Timing Recovery in the Presence of a Residual Echo Signal

This paper deals with the problem of symbol timing recovery at the subscriber end of a full duplex two wire digital subscriber loop employing echo cancellation. Both nondecision-aided and decisionaided synchronization are considered. It is demonstrated that the presence of a residual echo signal can substantially degrade the synchronizer performance. This degradation is shown to be larger for nondecisionaided synchronizers than for decision-aided synchronizers. The smaller the synchronizer bandwidth and the signal-to-echo ratio, the more the decision-aided synchronizer outperforms the nondecision-aided synchronizer.