An Efficient Finite Precision Realization of the Adaptive Decision Feedback Equalizer

A scheme for efficient finite precision realization of the adaptive decision feedback equalizer using block floating point (BFP) arithmetic is presented. The scheme adopts separate BFP formats for the feed forward and the feedback filter weights and works out separate update relations for their respective mantissas and exponents. Care is taken to prevent overflow in all computations by using a dynamic scaling of the data and a carefully chosen upper bound for the step size mu. Since no block processing of the feedback input is possible, an efficient scheme is presented for block formatting the data stored in the feedback filter memory, at each time index. The proposed scheme mostly employs simple fixed point operations and achieves considerable speed up over its floating point counterpart.