ECE1352F Term Paper Decision Feedback Equalizers and their Application to Magnetic Storage Read Channels

Intersymbol interference (ISI) can be a major speed-limiting factor in high-speed communications links, and must be mitigated to achieve an acceptable bit-error rate (BER). One efficient method of ISI mitigation is channel equalization using a decision-feedback equalizer (DFE) [1]. One system in which DFEs have been implemented extensively to combat severe ISI is the magnetic storage read channel. Many DFE architectures for this application have been proposed and implemented ([1],[2],[3]) . This paper describes the motivation for the development of DFEs for use in high-speed communications systems, and in particular, the magnetic storage read channel. The operation and architecture of the DFE is described and several recent mixed-signal and analog implementations of DFEs are presented and compared. In particular, the Look-Ahead DFE (LADFE) and Random Access Memory DFE (RAM-DFE) are shown to provide substantial performance improvements over other architectures.