Technique for controlling memoryful non-linearities

Abstract

The influence of memoryful non-linearities on a serial data sequence is combatted by initially analyzing a transmitted test or training data sequence, the contents of which are known and, from this analysis, a decoding scheme, referred to as a look-up table, is prepared. The look-up table contains a set of averaged threshold parameters with which subsequently received data signals, the values of which are unknown, are to be compared. From these comparisons, decisions are made as to what data signals were actually transmitted. Further, the decisions may be refined by carrying out a second iteration of comparisons on the previous choice for the sequence of transmitted data signals, thereby enhancing the reduction in error rate. Implementation of the above technique may incorporate a storage device such as a conventional random access memory into which threshold values for a sequence of training data signals are written during a training transmission and, for each identification of the same data symbol, its threshold value in memory is updated by averaging the new value with each of the received preceding values, so that, at the end of the training sequence, the memory contains threshold comparison values representative of the average value of each data symbol transmitted.