Patent ID: 8139681

Claim:
A system comprising: a receiver for acquiring a communications signal, comprising a series of information symbols, through a propagation channel; and an apparatus for deducing one or more frequency error estimates from a digital signal produced by the receiver to represent the communications signal, the apparatus configured for analyzing the digital signal representing the communications signal, comprising the series of information symbols, that has been acquired by the receiver through the propagation channel, the apparatus comprising: symbol estimation means for processing samples of the digital signal to estimate symbols of the communications signal; sample simulation means for modeling at least one sample of the digital signal using the estimated symbols and knowledge about the propagation channel; phase error estimation means for comparing a modeled sample of the digital signal with an actual sample of the digital signal to estimate a phase error in the latter sample; frequency error estimation means for estimating a frequency error from phase errors produced by the phase error estimation means, wherein each phase error produced by the phase error estimation means is made available for correction of the digital signal sample, if any, that follows the digital signal sample on which the phase error was estimated, wherein the receiver comprises frequency conversion means for down-converting the received communications signal in frequency and frequency control means for controlling the frequency conversion means on the basis of one or more frequency error estimates.