Study of fractionally-spaced equalizers for bit-patterned media recording

Bit-patterned media recording (BPMR) is a promising technology for next generation hard disk drives because it can achieve an areal density (AD) up to 4 Tbit/in². Generally, a T-spaced equalizer (TSE) is employed in a (symbol-rate) BPMR channel to suppress both inter-track interference (ITI) and inter-symbol interference (ISI). However, we found that the BPMR channel response has large excess bandwidth, where a fractionally-spaced equalizer (FSE) can be used to improve the BPMR system performance. Therefore, this paper proposes and studies the performance of an FSE (oversampled) system in BPMR channels.