A decision-directed symbol timing recovery circuit for ATSC digital TV receivers

We present and analyze a full-digital decision-directed symbol timing recovery circuit based on the double-sampling maximum-likelihood estimator. Intended for the ATSC digital TV system, the proposed scheme works independently of the segment synchronization by extracting timing information from the randomized data symbols even in the extremely small roll-off case. With the proposed method we get not only quick synchronization, but also robust timing recovery with reduced timing jitter compared to the conventional correlation method. The simulation is performed using the 8-level PAM signal, and evaluated in terms of the steady-state timing jitter under AWGN and multipath ghost channels. Additionally, initial timing acquisition and segment synchronization performance are also shown.