Techniques for minimizing error propagation in decision feedback detectors for recording channels

Abstract

Decision feedback equalization (DFE) is a low-cost approach for signal detection in magnetic recording channels. However, it suffers from the phenomenon of error propagation (EP). In this paper, two approaches are proposed for minimizing EP in DFE. The first approach imposes appropriate constraints on the feedback equalizer. The second approach uses simple threshold techniques to detect the presence of decision errors and to either correct these errors or minimize the possibility of further errors. Computer simulations show that the proposed techniques reduce EP very significantly. Theoretical analyses of the threshold techniques are presented to quantify the associated false and correct detection probabilities. By combining the analysis with an existing EP simulation method, a fast simulation procedure is derived for estimating EP and bit error rate (BER).