In perpendicular magnetic recording (PMR), we require a PR1 detector that can withstand the DC level shift caused by thermal asperity and other factors. In general, the DC level shift can be reduced by introducing a decision feedback equalizer (DFE) before the PR1 detector. However, the operation of the DFE tends to become unstable when large signal level fluctuations occur due to burst error. Therefore, we require a robust method to solve this problem. Another difficulty arises when the fluctuation of the magnetization transition area causes the so-called media noise such as jitter or the shift of edge positions of data series. Jitter-like noise essentially exhibits pattern-dependent properties because it depends on the edges of data series. Thus, we aim to develop a simple detector that can withstand jitter-like noise.
展开▼
