MMSE timing recovery using multi-channel early-late gates for analog multi-tone systems

A timing recovery scheme for high-speed wireline multi tone communication systems called Analog Multi-Tone (AMT) has been proposed. An accurate timing recovery is essential to a reliable high-speed AMT system which demodulates in analog domain. However, it is difficult to apply conventional digital domain timing recovery algorithms to AMT systems because of the limitations of power consumption and area occupation. This paper proposes a new timing recovery scheme for AMT systems without high-speed high-resolution ADCs. The proposed scheme minimizing mean square error (MSE) by sign-sign least mean square (SS-LMS) algorithm successfully estimates the timing offset for timing recovery. We call the proposed scheme multi-channel early-late gates because it is an extension of conventional early-late gate. The constellation diagram of demodulated signals after timing recovery and the convergence curves of timing estimate and MSE are simulated for performance evaluation. The simulation results indicate that the proposed scheme successfully estimates the timing offset for timing recovery in AMT systems without high-speed high-resolution ADCs and complex digital processing units.