An improved symbol timing error detector for QPSK signals

In this paper, based on analyzing the characteristics of the traditional timing error detectors, a new detector is proposed for quadratic phase shift keying (QPSK) signals. It makes use of the implicit timing information where there is no transition between consecutive symbols. Compared with the conventional timing error detector, the proposed one can improve the open loop performance. With the improved slope of the proposed detector´s S-curve, its residual timing jitter is investigated by simulation. Results show that the proposed estimator can reduce the self noise jitter in some degree, especially at medium-to-high SNR range.