A
receiver is described for optical or electromagnetic signals comprising a digital
equalizer and a
Forward Error Correction, said digital
equalizer and FEC combined together to obtain an iterative
equalization and error-correction loop, plus a method is described for improving the exactness in relating binary data to a digitalized-data transmitting, analog electromagnetic or optical-electrical
signal arriving at a
receiver, comprising the steps a) transforming the arriving analog signals into analog signals in the form of digital
soft data representing interim values, which indicate the value of the amplitude of the
analog signal, b) feeding the
soft data to a digital
equalizer, c) sequential determination of the interim value representing the boundary at which the decision would have to be made whether a ‘0’ or a ‘1’ had to be related to the
soft data when transformed to binary data in the digital equalizer, d) feeding the soft-
data signal further processed in the way described to a soft-in / soft-out FEC, e) error correction of the soft data by means of the check bits contained in the
signal, f) removal of the check bits, g) output of the error-corrected
signal in the form of soft data, h) preprocessing the signal for reinjection into a digital equalizer, i) feeding back the signal to the digital equalizer placed in the signal path, and k) repeating steps c) to j) until no further improvement of the
data quality can be detected or until a predefined number of iteration loops have been executed, and l) hard decision and transformation of the soft data preprocessed in the way described into binary data.