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实现超高密度硬盘驱动器的信号处理系统. PRML系统性能的计算机仿真评估利用计算机仿真得到的误比特率性能和差错模式，对三种GPRML系统进行了研究。GPRML系统由作为第一均衡目标的PR 1、dicode和FR信道构成。结果表明，GPR-FRML信道性能优于其他PRML系统，且单比特错误是判决错误的主要原因.本文研究了多磁道孤岛对准的方法。它是澄清，再现系统是实现与一个轨道系统的性能相比，如果每个岛是由每个轨道上的半比特间隔移位的性能下降。LDPC码编码与迭代译码的应用研究了LDPC码垂直磁记录系统中APP译码器与和积译码器之间的迭代译码系统。结果表明，迭代译码系统具有较好的译码性能，并通过权值控制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.