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Revision as of 16:03, 5 January 2023

Revision as of 16:04, 5 January 2023

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* Invert the whole stream when inverted [[syncword]]s are detected, perhaps using [[ differential signalling#Polarity switching | polarity switching ]]

==Run-length limited codes==A

For reliabljereliable [[clock recovery]] at the receiver, a [[Run-length limited|run-length limitation]] may be imposed on the generated channel sequence, i.e., the maximum number of consecutive ones or zeros is bounded to a reasonable number. A clock period is recovered by observing transitions in the received sequence, so that a maximum run length guarantees sufficient transitions to assure clock recovery quality.

RLL codes are defined by four main parameters: ''m'', ''n'', ''d'', ''k''. The first two, ''m''/''n'', refer to the rate of the code, while the remaining two specify the minimal ''d'' and maximal ''k'' number of zeroes between consecutive ones. This is used in both [[telecommunication]] and storage systems that move a medium past a fixed [[recording head]].<ref>{{Cite journal

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|url=https://www.researchgate.net/publication/3179483

|pages=491–497

|quote=A high-density alternative to EFM is described.}}</ref> Higher density RLL (2,7) and RLL (1,7) codes became the [[de facto standard]]s for hard disks by the early 1990s.{{citation needed|date=August 2019}}data surface ignore hard disk out run standard

Fjhfjrjkdyoxkydkxgkstmmtwksgkstkts4wjwtksge6mcpr6igialstldyl8ritiieiwtldldtdyuydkarkydfbxhjgzkzjfLfhlylxgldtjuistlsow5odmydy,nckgxnxgkggksjlddykykdysstkkdykdyldylxgkstkstkstsldsydykstk

== Synchronization ==