PRML system for ultra high density hard disk drive using patterned media

研究了PRML系统和迭代译码系统作为超高密度硬盘的信号处理系统。利用计算机仿真得到的误码率、性能和误码模式对三种GPRML系统进行了研究。GPRML系统由PR1、DICODE和FR信道作为第一均衡目标来构建。结果表明，与其他PRML系统相比，GPR-FRML信道具有更好的性能，判决错误以单位误码为主。一种用于多轨道复制的孤岛对准方法研究了一种用于双轨道块复制系统的位模式对准方法。研究表明，如果每个岛在每个轨道上移位半个比特间隔，则与一个轨道系统的性能相比，实现该再现系统的性能仅有很小的下降。研究了LDPC码垂直磁记录系统中APP译码与和积译码之间的迭代译码系统。结果表明，迭代译码系统表现出较好的译码性能，采用加权控制的方法缓慢提高译码可靠性，提高了译码性能。

Both PRML system and iterative decoding system are studied as signal processing system to implement ultra high density hard disk drive.1. Performance evaluation of PRML systems by computer simulationThree kinds of GPRML systems are studied using bit error rate performance and error patterns obtained by computer simulation. The GPRML systems are constructed from PR1, dicode, and FR channels as first equalization target. The results show that GPR-FRML channel shows better performance compared with other PRML systems, and single-bit error is dominant as decision error.2. A study of island alignment to reproduce on multi-tracksBit-pattern alignment is studied for a two-track lump reproducing system. It is clarified that the reproducing system is realized with a few performance degradation compared with the performance of one track system, if each island is shifted by half bit interval on each track.3. Application of LDPC coding and iterative decodingIterative decoding system is studied between APP decoder and Sum-product decoder for a perpendicular magnetic recording system with LDPC code. The results show that the iterative decoding system shows better performance and the decoding performance is improved by increasing the decoding reliability slowly using weight control.