Equalizer for the correction of digital signals

DETAILED DESCRIPTION I claim: 1.
An equalizer for eliminating the effects of postcursor and precursor interference from a periodically sampled train of incoming digital signals, comprising: receiving means connected to a transmission path carrying said incoming signals; a first circuit branch connected to said receiving means, said first branch including first upstream filter means for converting a given signal sample into a first linearly prefiltered signal with at least partial suppression of postcursor effects, first threshold means connected to said first upstream filter means for deriving a first quantized pulse from said first prefiltered signal, first downstream filter means connected to said first threshold means for generating a precursor-compensating signal from said first quantized pulse, and first delay means connected in parallel with said first threshold means to said first upstream filter means for emitting a first retarded signal corresponding to said first prefiltered signal; a second circuit branch connected in parallel with said first circuit branch to said receiving means, said second branch including second upstream filter means for converting said given signal sample into a second linearly prefiltered signal with at least partial suppression of precursor effects, said second branch further including second delay means connected to said second upstream filter means for emitting a second retarded signal corresponding to said second prefiltered signal, the retardations introduced by said first and second delay means being identical and exceeding by one sampling period a lag introduced by the series combination of said first threshold means and said first downstream filter means; summing means with inputs connected to said first and second delay means and to said first downstream filter means for receiving said first and second retarded signals and said precursor-compensating signal therefrom; second threshold means connected to said summing means for deriving a second quantized pulse from the combination of signals received by said summing means; and second downstream filter means connected in a feedback loop between an output of said second threshold means and a further input of said summing means for delivering thereto a postcursor-compensating signal, derived from said second quantized pulse, with a delay of one sampling period