A zero-pole whitening filter in adaptive blind decision feedback equalizers

This paper proposes the use of a novel recursive zero-pole whitening filter (ZPWF) instead of the all-pole whitening filter (APWF) and the all-zero whitening filter (AZWF) in the adaptive blind decision feedback equalizer (DFE) system. Both the APWF and the AZWF are special cases of the proposed ZPWF. The rationale for proposing the ZPWF may be explained as follows. Any arbitrary non-minimum phase channel may be approximated by the following three different types of channel: the moving-average (MA) channel, the autoregressive (AR) channel and the autoregressive-moving-average (ARMA) channel. The MA channel or the AR channel may be more effectively approximated by the ARMA channel with a much smaller total (numerator and denominator) number of coefficients. From the perspective of channel equalization, the APWF and the AZWF may merely suit a particular type of channel, while the proposed ZPWF may suit most channels in general.