Equalizer which opens the eye of received signal by adjusting tap coefficients to move unreliable outputs towards reliability thresholds

摘要

A method of equalizer adaptation involves comparing equalizer output values with a centre threshold, and with at least one of a pair of outer thresholds, and adapting the equalizer in order to increase the degree of eye opening. The centre threshold represents the zero/one crossover boundary, while the outer thresholds represent a desired level of confidence in the equaliser output. The values of the outer thresholds are adapted such that a fixed proportion of equalizer output values lie between the outer thresholds, and the equalizer coefficients are adapted such the separation of the outer thresholds is increased. The equalizer coefficients are adapted on the basis of equalizer output values which lie between the pair of outer thresholds. Thus the coefficients are updated based upon the unreliable outputs and adjusted so that the output values move away from the centre threshold and thereby become more reliable.