ADAPTIVE DECISION FEEDBACK EQUALIZER USING THE HIERARCHICAL FEEDBACK FILTER AND SOFT DECISION DEVICE

摘要

An adaptive decision feedback equalizer is provided to prevent erroneous determination of an estimated symbol and to improve performance of a receiver by applying a soft decision device to a signal determination device using a hard decision device. An adaptive decision feedback equalizer(1) includes equalizer filters(10,30), a filter coefficient storage device, a signal output device, and a signal determination device(50). The equalizer filters prevent error propagation by removing Pre-ISI(Precursor-Inter Symbol Interference) or Post-ISI(Postcursor-Inter Symbol Interference) of an input signal having actual information based on an inputted training sequence. The filter coefficient storage device stores filter coefficients for removing the Pre-ISI or the Post-ISI measured by the equalizer filters. The signal output device multiplies the input signal with the filter coefficients stored in the filter coefficient storage device to compensate for distortion of the input signal. The signal determination device estimates accurate information about signals outputted to a soft decision device(53) and a hard decision device(51).