Adaptive adjustment of digital data receivers using pre-detection filtering

Describes methods used for the adjustment of a decision feedback equalizer in a digital data transmission system. The equalizer minimizes noise in the equalized signal subject to exact equalization of the channel. The equalizer employs an adaptive linear feedforward filter at its input which replaces the roots of the Z-transform of the channel that lie outside the unit circle by the complex conjugate of their reciprocals. The results of computer simulations are presented for various schemes that are used in the adjustment of the linear filter, when operating over band-limited telephone channels