用於數位記錄通道具改錯能力的RLL碼

Abstract

一般所使用的RLL碼不具改錯的能力. 在某些狀況下, 其解碼器甚至會放 大由通道所造成的錯誤. 若RLL碼能改掉部份通道所造成的錯誤, 則所需 用的改錯碼的複雜度也會降低.在本論文中, 研究了可改錯的RLL格狀碼及 可改錯的RLL區塊碼. 所求出的可改錯RLL格狀碼具太低的碼率及太多的狀 態. 因此這類的碼不適合實用. 至於可改錯的RLL碼則能容易地被編碼與 解碼. The conventional runlength-limited (RLL) codes have no error- correcting capabilities. In some cases, their decoders even amplify the errors caused by the channel. If the RLL codes can correct some channel errors, the complexity of the ECC codes can be decreased. In this thesis, both error-correcting RLL trellis and block codes are studied. The derived error- correcting RLL trellis codes have low code rate and large number of states. Hence, they are not suitable for practical use. However, the error- correcting RLL block codes can be easily encoded and decoded.