A study of a symbol-rate timing recovery algorithm for a digital ISDN U-transceiver.

Abstract

A symbol rate timing recovery scheme suitable for ISDN transmission on digital subscriber loops is investigated. Four timing estimates based on this scheme are studied for steady-state and convergence behavior. Theoretical analysis and simulation results are included. The effect of the various system parameters such as channel distortion, noise and dead-zone threshold is examined for the four timing estimates. Their performance on realistic loops in a practical U-transceiver using 2B1Q line code is characterized and compared. The performance will be evaluated principally by the receiver convergence, steady-state timing jitter and noise margin allowed before convergence is lost.