Near optimum timing recovery for digitally implemented data receivers

A timing recovery scheme based on the maximization of the spectrum of the sampled received signal at the frequency of f-=1/2T is proposed. The quadrature amplitude modulated data signals are considered. Algorithms for both initial adjustment of the timing phase and its tracking during transmission of actual data bits are developed. The algorithms are tested by computer simulations for a typical telephone line channel. It is shown that the proposed scheme is quite robust with respect to channel impairments such as noise and phase jitter and also with respect to the correlation to the transmitted data symbols