US Patent 8644416 Method and system for accurately converging a timing recovery mechanism and an equalizer at a receiver

A transmitter transmits to a receiver a training sequence having symbols belonging to a single modulation scheme. At least 90% of symbols have low symbol amplitude, and at most 10% of the symbols have high symbol amplitude. A first symbol estimator estimates the symbols using substantially only the sign of the received symbols, and substantially disregarding symbol amplitudes. A timing recovery mechanism estimates the received symbols in order to continuously reduce a frequency drift between the receiver and the transmitter. The first symbol estimator is switched off and a second symbol estimator is switched on according to a certain criterion. The second symbol estimator estimates symbols belonging to the training sequence. Each of the symbols is estimated to either the low symbol amplitude or the high symbol amplitude. An equalizer uses the symbols estimated by the second symbol estimator to converge, achieve signal equalization, and eliminate inter-symbol interference.