A new pattern jitter free frequency error detector

One method to enable fast acquisition of a phase-locked loop (PLL) in spite of large frequency offsets and small PLL bandwidths is to use an additional AFC loop. A suitable frequency error detector (FED) for large frequency offsets is the well-known balanced quadricorrelator. This FED is shown to produce great pattern jitter if it is to work with digital modulated MQAM and MPSK signals (M > 2) and random data. This paper describes how this pattern jitter for MQAM and MPSK signals can be overcome completely. Another understanding of the balance quadricorrelator is also given.