Editing 8b/10b encoding (section)

{{Short description|Line code mapping 8-bit words to 10-bit symbols}}
{{redirect|8/10|the dates|August 10|and|October 8}}
{{use mdy dates|date=September 2021}}
{{Use American English|date = March 2019}}
{{More citations needed|date=January 2015}}

{{Fibre Channel}}

In [[telecommunication]]s, '''8b/10b''' is a [[line code]] that maps [[8-bit]] words to [[10-bit]] [[Symbol (data)|symbol]]s to achieve [[DC balance]] and bounded disparity, and at the same time provide enough state changes to allow reasonable [[clock recovery]].  This means that the difference between the counts of ones and zeros in a string of ''at least'' 20 bits is no more than two, and that there are not more than five ones or zeros in a row. This helps to reduce the demand for the lower bandwidth limit of the channel necessary to transfer the signal.<ref>{{Cite journal |journal=IEEE Transactions on Communications |volume=45 |issue=3 |date=March 1997 |title=Performance Assessment of DC-Free Multimode Codes |author=Kees Schouhamer Immink |author-link=Kees Schouhamer Immink |pages=293–299 |doi=10.1109/26.558690 |quote=The ''dc-balanced'' or ''dc-free'' codes, as they are often called, have a long history and their application is certainly not confined to recording practice.}}</ref>

An 8b/10b code can be implemented in various ways with focus on different performance parameters. One implementation was designed by K. Odaka for the [[Digital Audio Tape|DAT]] digital audio recorder.<ref>{{cite patent |country=US |number=4,456,905 |title=Method and apparatus for encoding binary data |pubdate=1984-06-26}}</ref> [[Kees Schouhamer Immink]] designed an 8b/10b code for the [[Digital Compact Cassette|DCC]] audio recorder.<ref>{{cite patent |country=US |number=4,620,311 |title=Method of transmitting information, encoding device for use in the method, and decoding device for use in the method |pubdate=1986-10-28}}</ref> The IBM implementation was described in 1983 by [[Al Widmer]] and [[Peter Franaszek]].<ref>{{cite journal
 | url = http://domino.research.ibm.com/tchjr/journalindex.nsf/0/b4e28be4a69a153585256bfa0067f59a?OpenDocument
 | title = A DC-Balanced, Partitioned-Block, 8B/10B Transmission Code
 | author = Al X. Widmer, Peter A. Franaszek
 | journal = IBM Journal of Research and Development
 | volume = 27
 | issue = 5
 | pages = 440–451
 | year = 1983
 | doi = 10.1147/rd.275.0440
 | access-date = April 5, 2005
 | archive-date = May 30, 2009
 | archive-url = https://web.archive.org/web/20090530123123/http://domino.research.ibm.com/tchjr/journalindex.nsf/0/b4e28be4a69a153585256bfa0067f59a?OpenDocument
 | url-status = dead
 | url-access = subscription
 }}</ref><ref>{{cite patent |country=US |number=4,486,739 |title=Byte oriented DC balanced (0,4) 8B/10B partitioned block transmission code |pubdate=1984-12-04}}</ref><!--[[User:Kvng/RTH]]-->