A new design of prefilter for reducing timing synchronization jitter

Abstract

SummaryFor high‐precision timing synchronization in feedback Gardner algorithm and different feedforward nonlinear algorithms, timing jitter reduction is the key problem, especially with a small roll‐off factor in high‐order modulation. Through the elaborate analysis about the timing jitter, this paper proposes a new prefilter design method based on finite impulse response structure. Using a suitable Kaiser window for suppressing the sidelobe energy of the proposed prefilter, this method can further decrease the complexity of filter design and eliminate most part of the pattern noise. Compared with the previous prefilter design algorithms, the approach has a better improvement in steady‐state phase jitter reduction without increasing the capture time in Gardner timing error detector. Meanwhile, with such kind of prefilter, the performance of logarithmic nonlinearity is better than that of square law nonlinearity, this is not reported in literature. Simulation results show that the residual timing jitter in both kinds of algorithms is closed to the modified Cramer‐Rao bound when the roll‐off factor is equal to 0.1 in 1024QAM.