A Reduced-Complexity Frequency Detector Derived from the Maximum-Likelihood Principle

Abstract

In addition to the conventional matched filter, implementation of Gardner's frequency detector (GFD) based on the maximum-likelihood principle also involves a frequency-matched filter. In this paper, we present a reduced-complexity frequency detector (RCFD) derived from Gardner's detector through a simple approximation to the frequency-matched filter. We 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. Our 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 this paper is the analysis of GFD and RCFD when their outputs are computed at twice the symbol rate. © 1995 IEEE