A reduced-complexity frequency detector derived from the maximum-likelihood principle

In addition to the conventional matched filter, implementation of Gardner´s (1990) frequency detector (GFD) based on the maximum-likelihood principle also involves a frequency-matched filter. the present authors give a reduced-complexity frequency detector (RCFD) derived from Gardner´s detector through a simple approximation to the frequency-matched filter. They analyze its steady-state jitter properties and frequency acquisition performance and compare it to the original GFD as well as to the well-known balanced quadricorrelator. The results show that performance of the RCFD is close to that of the original GFD and that this detector significantly outperforms the balanced quadricorrelator which involves a similar hardware complexity. Another contribution of the paper is the analysis of GFD and RCFD when their outputs are computed at twice the symbol rate