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的信号处理系统。通过计算机仿真对三种GPRML系统的误码率性能和误码率进行了研究。GPRML系统以PR1、dicode和FR通道作为第一均衡目标。结果表明，GPR-FRML通道与其他PRML系统相比具有更好的性能，且决策误差以单比特误差为主。研究了多航迹块再现系统的孤岛对准问题。结果表明，如果每个岛在每条轨道上移动半比特间隔，则与单轨道系统相比，该再现系统的性能下降较少。LDPC编码与迭代译码的应用研究了LDPC码垂直磁记录系统的APP解码器与和积解码器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，并通过权值控制逐步提高译码可靠性来提高译码性能。

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.