Blind phase synchronization for VSB signals
H Mathis · IEEE Transactions on Broadcasting · 2001
Starting out with a strong justification for phase synchronization, we derive the symbol error probability for 8-vestigial sideband (VSB) in the presence of phase errors and compare it with the symbol error rates for 8-PAM and 64-QAM. Monte Carlo simulations support the theoretical expressions. Phase misadjustments lead to error floors, which are computed, and which further reveal the susceptibility of VSB signals to phase errors. Phase synchronizers can either work in a data-aided manner or blindly. We focus on the latter and show the relationship between phase synchronization and blind source separation (BSS). Finally, a method suitable for the phase synchronization of VSB signals as used by the ATSC DTV transmission system is presented and evaluated. Its performance is measured against that of the decision-directed approaches that have been suggested in the literature. Depending on the SNR of the VSB signal, either blind or decision-directed approaches exhibit superior performance. A semiblind method, which combines the advantages of the decision-directed and the blind mode in their respective SNR regions, is introduced and set in perspective with the other algorithms.