Comparison between digital phase recovery techniques in the presence of a frequency shift

Analyzes the behaviour of different digital phase recovery techniques in the presence of a frequency offset. Comparison is given in terms of phase error variance and acquisition time. The authors show that the sliding block version of the expectation maximization estimator algorithm [Qin, 1993] for QPSK phase recovery, in the presence of non-negligible frequency errors (/spl Delta/fT/spl ap/10/sup -3/), gives results which are comparable or even better than those of the Viterbi and Viterbi non-decision aided nonlinear phase estimator [Viterbi and Viterbi, 1983].<
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