Automatic and adaptive digital nonlinear decision feedback equalizer

摘要

A method and apparatus for equalizing a scanned noisy digital signal with an automatic and adaptive decision feedback equalizer comprising a nonrecursive part and a recursive part. A switch is disposed in the feedback loop of the equalizer between a decision device and the recursive part of the equalizer for allowing the determination of a step size factor. For this purpose the switch is in such a position that a reference signal can be fed into the feedback loop and at the same time the gradient coefficients are fed to a device for setting the filter coefficients. The gradient coefficients are determined at that point in time where the switch was set to the other switch setting. The number of the required interation intervals to approaching the minimum of the equalization error can be decreased by employing the method of the present invention. In addition, the filter configuration can be employed in a multiplex operation.