RESEARCH ON HIGHER DENSITY RECORDING FOR HARD DISK SYSTEM BASED ON TRELLIS METHOD

本项目开发了新的鲁棒记录代码，结合信号处理技术，包括基于网格法的硬盘系统高密度记录的维特比探测器。近年来，主要的研究人员已经注意到，在传统的简单（d, k）极限和一维二能级技术的约束下，新码的辉煌发展是非常困难的。他们还提出了未来有前景的编码方法必须涉及以下一种或几种技术：(1)提高编码增益；(2)实现多级记录；(3)扩展到多轨记录。我们的想法源于这样一个事实，即每个记录码，部分响应（PR）均衡器和维特比检测器都可以根据有限状态自动化理论建模。我们成功地开发了几种新的鲁棒TCPR（网格编码PR）代码，这些代码使用了上述所有模型的组合方法。第一年，开发了编码率为eta = 1/2、2/3和3/4的一维TCPR（1,1）码，并将误码率（BER）特性与NRZI码加PR(1,1)ML方法的普通记录系统进行了比较，证实了在归一化记录密度K = 2.4时，前者优于后者。当时可实现的最高密度)。在接下来的一年里，验证了在K <大于等于bbb1.2的情况下，TCPR（1,1）系统比TCPR（1, -1）系统在BER上保持优先级。我们还开始研究将二维技术引入tcpp的可能性。在最后一年，开发了几个新的鲁棒代码，这些代码包含了所有二维技术，MTR（最大过渡运行）属性和网格函数。

This project has developed new robust recording codes combined with signal processing techniques included Viterbi detector for higher density recording of hard disk system based on trellis method.Recently major researchers have noticed that the splendid development of new codes would be very difficult under the constraints of conventional simple (d, k) limits and one-dimensional two level techniques. They also suggested that the future prospective coding methods must be involved one or some following techniques,(1) improvement of coding gain,(2) realization of multi-level recording,and(3) expansion to multi-track recording.Our idea originates from the fact that evey recording codes, partial response (PR) equalizers and Viterbi detectors can be modeled after finite state automation theory.We have successfully developed several new robust TCPR(trellis coded PR) codes which use the combination method of all models above mentioned.In the first year, one-dimensionl TCPR(1,1) codes with the coding rate eta = 1/2, 2/3 and 3/4 have been developed and compared bit error rate(BER) characteristics with the ordinary recording system on NRZI code plus PR(1,1)ML method, Then we confirmed the supericrity of the former over the latter at the normalized recording density K = 2.4(i.e. the realizable highest density at that time).In the next year, it has been verified that TCPR(1,1) system can hold the priority on BER over TCPR(1, -1) system at the case K <greater than or equal> 1.2. We also started to investigate the possibility of introduction on two-dimensional technique to TCPIn the final year, several new robust codes partaking all of two-dimensional technique, MTR(maximum transition run) property and trellis function have been developed.