Line code - Revision history

Decoy: /* Polarity */spelling

2025-06-04T09:31:40Z

Polarity: spelling

← Previous revision		Revision as of 09:31, 4 June 2025
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	== Polarity ==		== Polarity ==
	Bipolar line codes have two polarities, are generally implemented as RZ, and have a radix of three since there are three distinct output levels (negative, positive and zero). One of the ~~principle~~ advantages of this type of code is that it can eliminate any DC component. This is important if the signal must pass through a transformer or a long transmission line.		Bipolar line codes have two polarities, are generally implemented as RZ, and have a radix of three since there are three distinct output levels (negative, positive and zero). One of the principal advantages of this type of code is that it can eliminate any DC component. This is important if the signal must pass through a transformer or a long transmission line.

	Unfortunately, several long-distance communication channels have polarity ambiguity. Polarity-insensitive line codes compensate in these channels.<ref>		Unfortunately, several long-distance communication channels have polarity ambiguity. Polarity-insensitive line codes compensate in these channels.<ref>

Zinnober9: Duplicate WP:EIS parameters not permitted

2025-03-19T05:58:24Z

Duplicate WP:EIS parameters not permitted

← Previous revision		Revision as of 05:58, 19 March 2025
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	{{stack\|		{{stack\|
	[[File:NRZcode.png~~\|class=skin-invert-image~~\|class=skin-invert-image\|thumb\|An example of coding a binary signal using rectangular [[pulse-amplitude modulation]] with polar [[non-return-to-zero]] code]]		[[File:NRZcode.png\|class=skin-invert-image\|thumb\|An example of coding a binary signal using rectangular [[pulse-amplitude modulation]] with polar [[non-return-to-zero]] code]]
	[[File:Ami encoding.svg\|class=skin-invert-image\|thumb\|An example of [[bipolar encoding]], or AMI.]]		[[File:Ami encoding.svg\|class=skin-invert-image\|thumb\|An example of [[bipolar encoding]], or AMI.]]
	[[File:Manchester code.svg\|class=skin-invert-image\|thumb\|Encoding of 11011000100 in [[Manchester encoding]] ]]		[[File:Manchester code.svg\|class=skin-invert-image\|thumb\|Encoding of 11011000100 in [[Manchester encoding]] ]]

JAlone: Improve dark mode display

2025-03-19T01:16:40Z

Improve dark mode display

← Previous revision		Revision as of 01:16, 19 March 2025
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	{{stack\|		{{stack\|
	[[File:NRZcode.png\|thumb\|An example of coding a binary signal using rectangular [[pulse-amplitude modulation]] with polar [[non-return-to-zero]] code]]		[[File:NRZcode.png\|class=skin-invert-image\|class=skin-invert-image\|thumb\|An example of coding a binary signal using rectangular [[pulse-amplitude modulation]] with polar [[non-return-to-zero]] code]]
	[[File:Ami encoding.svg\|thumb\|An example of [[bipolar encoding]], or AMI.]]		[[File:Ami encoding.svg\|class=skin-invert-image\|thumb\|An example of [[bipolar encoding]], or AMI.]]
	[[File:Manchester code.svg\|thumb\|Encoding of 11011000100 in [[Manchester encoding]] ]]		[[File:Manchester code.svg\|class=skin-invert-image\|thumb\|Encoding of 11011000100 in [[Manchester encoding]] ]]
	[[File:Differential_manchester_encoding_Workaround.svg\|thumb\|An example of [[differential Manchester encoding]]]]		[[File:Differential_manchester_encoding_Workaround.svg\|class=skin-invert-image\|thumb\|An example of [[differential Manchester encoding]]]]
	[[File:Biphase Mark Code.svg\|thumb\|An example of [[biphase mark code]] ]]		[[File:Biphase Mark Code.svg\|class=skin-invert-image\|thumb\|An example of [[biphase mark code]] ]]
	[[File:MLT3encoding.svg\|thumb\|An example of [[MLT-3 encoding]]]]		[[File:MLT3encoding.svg\|class=skin-invert-image\|thumb\|An example of [[MLT-3 encoding]]]]
	}}		}}
	{{Modulation techniques}}		{{Modulation techniques}}
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	\|}		\|}

	[[File:Digital signal encoding formats-en.svg\|framed\|center\|An arbitrary bit pattern in various binary line code formats]]		[[File:Digital signal encoding formats-en.svg\|class=skin-invert-image\|framed\|center\|An arbitrary bit pattern in various binary line code formats]]

	Each line code has advantages and disadvantages. Line codes are chosen to meet one or more of the following criteria:		Each line code has advantages and disadvantages. Line codes are chosen to meet one or more of the following criteria:

Kvng: avoid unnec redirect

2024-09-16T00:30:33Z

avoid unnec redirect

← Previous revision		Revision as of 00:30, 16 September 2024
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	For reliable [[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.		For reliable [[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		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 [[telecommunications]] and storage systems that move a medium past a fixed [[recording head]].<ref>{{Cite journal
	\|journal=Proceedings of the IEEE		\|journal=Proceedings of the IEEE
	\|volume=78		\|volume=78

Kvng: avoid unnec redirect

2024-09-15T23:22:50Z

avoid unnec redirect

← Previous revision		Revision as of 23:22, 15 September 2024
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	{{short description\|Pattern used within a communications system to represent digital data}}		{{short description\|Pattern used within a communications system to represent digital data}}

	{{stack\|		{{stack\|
	[[File:NRZcode.png\|thumb\|An example of coding a binary signal using rectangular [[pulse-amplitude modulation]] with polar [[non-return-to-zero]] code]]		[[File:NRZcode.png\|thumb\|An example of coding a binary signal using rectangular [[pulse-amplitude modulation]] with polar [[non-return-to-zero]] code]]
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	{{Modulation techniques}}		{{Modulation techniques}}

	In [[~~telecommunication~~]], a '''line code''' is a pattern of voltage, current, or photons used to represent digital data [[transmission (telecommunications)\|transmitted]] down a [[communication channel]] or written to a [[storage medium]]. This repertoire of signals is usually called a '''constrained code''' in data storage systems.<ref>{{Cite journal		In [[telecommunications]], a '''line code''' is a pattern of voltage, current, or photons used to represent digital data [[transmission (telecommunications)\|transmitted]] down a [[communication channel]] or written to a [[storage medium]]. This repertoire of signals is usually called a '''constrained code''' in data storage systems.<ref>{{Cite journal
	\|journal= IEEE Communications Magazine		\|journal= IEEE Communications Magazine
	\|date=2022		\|date=2022

50.39.133.23: /* Common line codes */Typo

2024-03-01T05:56:51Z

Common line codes: Typo

← Previous revision		Revision as of 05:56, 1 March 2024
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	* [[Non-return-to-zero]] (NRZ)		* [[Non-return-to-zero]] (NRZ)
	* [[Non-return-to-zero, inverted]] (NRZI)		* [[Non-return-to-zero, inverted]] (NRZI)
	* [[Pulse-position modulation]] (~~PAM~~)		* [[Pulse-position modulation]] (PPM)
	* [[Return-to-zero]] (RZ)		* [[Return-to-zero]] (RZ)
	* [[TC-PAM]]		* [[TC-PAM]]

Kerel-fs: /* Common line codes */ Add abbreviation: PAM

2024-02-29T13:52:54Z

Common line codes: Add abbreviation: PAM

← Previous revision		Revision as of 13:52, 29 February 2024
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	* [[Non-return-to-zero]] (NRZ)		* [[Non-return-to-zero]] (NRZ)
	* [[Non-return-to-zero, inverted]] (NRZI)		* [[Non-return-to-zero, inverted]] (NRZI)
	* [[Pulse-position modulation]]		* [[Pulse-position modulation]] (PAM)
	* [[Return-to-zero]] (RZ)		* [[Return-to-zero]] (RZ)
	* [[TC-PAM]]		* [[TC-PAM]]

Onel5969: Disambiguating links to Code word (link changed to Code word (communication)) using DisamAssist.

2023-10-24T01:32:50Z

Disambiguating links to Code word (link changed to Code word (communication)) using DisamAssist.

← Previous revision		Revision as of 01:32, 24 October 2023
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	Most line codes eliminate the DC component{{snd}} such codes are called [[DC-balanced]], zero-DC, or DC-free. There are three ways of eliminating the DC component:		Most line codes eliminate the DC component{{snd}} such codes are called [[DC-balanced]], zero-DC, or DC-free. There are three ways of eliminating the DC component:

	* Use a [[constant-weight code]]. Each transmitted [[code word]] in a constant-weight code is designed such that every code word that contains some positive or negative levels also contains enough of the opposite levels, such that the average level over each code word is zero. Examples of constant-weight codes include [[Manchester code]] and [[Interleaved 2 of 5]].		* Use a [[constant-weight code]]. Each transmitted [[Code word (communication)\|code word]] in a constant-weight code is designed such that every code word that contains some positive or negative levels also contains enough of the opposite levels, such that the average level over each code word is zero. Examples of constant-weight codes include [[Manchester code]] and [[Interleaved 2 of 5]].
	* Use a [[paired disparity code]]. Each code word in a paired disparity code that averages to a negative level is paired with another code word that averages to a positive level. The transmitter keeps track of the running DC buildup, and picks the code word that pushes the DC level back towards zero. The receiver is designed so that either code word of the pair decodes to the same data bits. Examples of paired disparity codes include [[alternate mark inversion]], [[8b/10b]] and [[4B3T]].		* Use a [[paired disparity code]]. Each code word in a paired disparity code that averages to a negative level is paired with another code word that averages to a positive level. The transmitter keeps track of the running DC buildup, and picks the code word that pushes the DC level back towards zero. The receiver is designed so that either code word of the pair decodes to the same data bits. Examples of paired disparity codes include [[alternate mark inversion]], [[8b/10b]] and [[4B3T]].
	* Use a [[scrambler]]. For example, the scrambler specified in {{IETF RFC \| 2615}} for [[64b/66b encoding]].		* Use a [[scrambler]]. For example, the scrambler specified in {{IETF RFC \| 2615}} for [[64b/66b encoding]].

Ira Leviton: Fixed a reference. Please see Category:CS1 errors: unsupported parameter.

2023-08-20T23:27:04Z

Fixed a reference. Please see Category:CS1 errors: unsupported parameter.

← Previous revision		Revision as of 23:27, 20 August 2023
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	== Disparity ==		== Disparity ==
	Most long-distance communication channels cannot reliably transport a [[DC component]]. The DC component is also called the ''disparity'', the ''bias'', or the [[DC coefficient]]. The disparity of a bit pattern is the difference in the number of one bits vs the number of zero bits. The ''running disparity'' is the [[running total]] of the disparity of all previously transmitted bits.<ref>{{cite ~~document~~ \|author=Jens Kröger \|url=https://www.psi.ch/mu3e/ThesesEN/BachelorKroeger.pdf \|archive-url=https://ghostarchive.org/archive/20221009/https://www.psi.ch/mu3e/ThesesEN/BachelorKroeger.pdf \|archive-date=2022-10-09 \|url-status=live \|title=Data Transmission at High Rates via Kapton Flexprints for the Mu3e Experiment \|date=2014 \|page=16}}</ref> The simplest possible line code, [[Unipolar encoding\|unipolar]], gives too many errors on such systems, because it has an unbounded DC component.		Most long-distance communication channels cannot reliably transport a [[DC component]]. The DC component is also called the ''disparity'', the ''bias'', or the [[DC coefficient]]. The disparity of a bit pattern is the difference in the number of one bits vs the number of zero bits. The ''running disparity'' is the [[running total]] of the disparity of all previously transmitted bits.<ref>{{cite web \|author=Jens Kröger \|url=https://www.psi.ch/mu3e/ThesesEN/BachelorKroeger.pdf \|archive-url=https://ghostarchive.org/archive/20221009/https://www.psi.ch/mu3e/ThesesEN/BachelorKroeger.pdf \|archive-date=2022-10-09 \|url-status=live \|title=Data Transmission at High Rates via Kapton Flexprints for the Mu3e Experiment \|date=2014 \|page=16}}</ref> The simplest possible line code, [[Unipolar encoding\|unipolar]], gives too many errors on such systems, because it has an unbounded DC component.

	Most line codes eliminate the DC component{{snd}} such codes are called [[DC-balanced]], zero-DC, or DC-free. There are three ways of eliminating the DC component:		Most line codes eliminate the DC component{{snd}} such codes are called [[DC-balanced]], zero-DC, or DC-free. There are three ways of eliminating the DC component:

TheManInTheBlackHat: Reverted 1 edit by 113.21.76.235 (talk) to last revision by DavidCary

2023-01-05T16:04:49Z

Reverted 1 edit by 113.21.76.235 (talk) to last revision by DavidCary

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

	==Run-length limited codes==A		==Run-length limited codes==
	For ~~reliablje~~ [[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.		For reliable [[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		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		\|url=https://www.researchgate.net/publication/3179483
	\|pages=491–497		\|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~~		\|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}}
	Fjhfjrjkdyoxkydkxgkstmmtwksgkstkts4wjwtksge6mcpr6igialstldyl8ritiieiwtldldtdyuydkarkydfbxhjgzkzjfLfhlylxgldtjuistlsow5odmydy,nckgxnxgkggksjlddykykdysstkkdykdyldylxgkstkstkstsldsydykstk

	== Synchronization ==		== Synchronization ==

← Previous revision		Revision as of 05:58, 19 March 2025
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	{{stack\|		{{stack\|
	[[File:NRZcode.png~~\|class=skin-invert-image~~\|class=skin-invert-image\|thumb\|An example of coding a binary signal using rectangular [[pulse-amplitude modulation]] with polar [[non-return-to-zero]] code]]		[[File:NRZcode.png\|class=skin-invert-image\|thumb\|An example of coding a binary signal using rectangular [[pulse-amplitude modulation]] with polar [[non-return-to-zero]] code]]
	[[File:Ami encoding.svg\|class=skin-invert-image\|thumb\|An example of [[bipolar encoding]], or AMI.]]		[[File:Ami encoding.svg\|class=skin-invert-image\|thumb\|An example of [[bipolar encoding]], or AMI.]]
	[[File:Manchester code.svg\|class=skin-invert-image\|thumb\|Encoding of 11011000100 in [[Manchester encoding]] ]]		[[File:Manchester code.svg\|class=skin-invert-image\|thumb\|Encoding of 11011000100 in [[Manchester encoding]] ]]

← Previous revision		Revision as of 01:16, 19 March 2025
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	{{stack\|		{{stack\|
	[[File:NRZcode.png\|thumb\|An example of coding a binary signal using rectangular [[pulse-amplitude modulation]] with polar [[non-return-to-zero]] code]]		[[File:NRZcode.png\|class=skin-invert-image\|class=skin-invert-image\|thumb\|An example of coding a binary signal using rectangular [[pulse-amplitude modulation]] with polar [[non-return-to-zero]] code]]
	[[File:Ami encoding.svg\|thumb\|An example of [[bipolar encoding]], or AMI.]]		[[File:Ami encoding.svg\|class=skin-invert-image\|thumb\|An example of [[bipolar encoding]], or AMI.]]
	[[File:Manchester code.svg\|thumb\|Encoding of 11011000100 in [[Manchester encoding]] ]]		[[File:Manchester code.svg\|class=skin-invert-image\|thumb\|Encoding of 11011000100 in [[Manchester encoding]] ]]
	[[File:Differential_manchester_encoding_Workaround.svg\|thumb\|An example of [[differential Manchester encoding]]]]		[[File:Differential_manchester_encoding_Workaround.svg\|class=skin-invert-image\|thumb\|An example of [[differential Manchester encoding]]]]
	[[File:Biphase Mark Code.svg\|thumb\|An example of [[biphase mark code]] ]]		[[File:Biphase Mark Code.svg\|class=skin-invert-image\|thumb\|An example of [[biphase mark code]] ]]
	[[File:MLT3encoding.svg\|thumb\|An example of [[MLT-3 encoding]]]]		[[File:MLT3encoding.svg\|class=skin-invert-image\|thumb\|An example of [[MLT-3 encoding]]]]
	}}		}}
	{{Modulation techniques}}		{{Modulation techniques}}
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	\|}		\|}

	[[File:Digital signal encoding formats-en.svg\|framed\|center\|An arbitrary bit pattern in various binary line code formats]]		[[File:Digital signal encoding formats-en.svg\|class=skin-invert-image\|framed\|center\|An arbitrary bit pattern in various binary line code formats]]

	Each line code has advantages and disadvantages. Line codes are chosen to meet one or more of the following criteria:		Each line code has advantages and disadvantages. Line codes are chosen to meet one or more of the following criteria: