Suppressed carrier synchronizers for ISI channels

We demonstrate a class of suppressed carrier synchronization loops that are motivated by MAP estimation theory, and in the presence of ISI outperform the conventional I-Q loop which is designed on the basis of zero ISI (wideband assumption). The measure of comparison used is the so-called “squaring loss” (the reduction in loop SNR relative to that of a phase-locked loop (PLL) of the same loop bandwidth) or equivalently the mean-squared phase jitter for equal loop bandwidths and signal power to noise power spectral density ratios