Talk:Manchester code

This is the talk page for discussing improvements to the Manchester code article.
This is not a forum for general discussion of the article's subject.

Put new text under old text. Click here to start a new topic.
New to Wikipedia? Welcome! Learn to edit; get help.

Article policies

Find sources: Google (books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL

Archives: 1: 12 months

Telecommunications C‑class Mid‑importance

	Telecommunication portal This article is within the scope of WikiProject Telecommunications, a collaborative effort to improve the coverage of Telecommunications on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.TelecommunicationsWikipedia:WikiProject TelecommunicationsTemplate:WikiProject TelecommunicationsTelecommunications
C	This article has been rated as C-class on Wikipedia's content assessment scale.
Mid	This article has been rated as Mid-importance on the project's importance scale.

Purpose

So, what does this code do?

Provides a simple way of encoding arbitary binary sequences without ever having long periods where there is all one voltage, thus losing clock synchronization. Also ensures that the DC component of the encoded signal is zero. -- The Anome 12:13, 18 Sep 2004 (UTC)

Aliases

Manchester code is commonly refered to as Bi-phase-level or split phase in telemetry documentation including the Range Commanders Council document IRIG 106. I belive it would be constructive to include these as my search from bi-phase-level did not produce any results. --138.64.8.53 14:09, 30 January 2007 (UTC)Thad Sterling[reply]

We have a lot of redirects to here that include biphase but that term is not mentioned in the article. Biphase does appear in Differential Manchester encoding. It is not perfectly clear to me in IRIG 106 that Bi-phase-level is the same as Manchester. ~Kvng (talk) 13:29, 26 March 2020 (UTC)[reply]

Manchester code = bi-phase mark code ?

Several articles that I read (perhaps originating from the same source) use bi-phase code and Manchester code as two equivalent terms for the same encoding. The description of "Biphase Mark Coding" here on Wikipedia (http://en.wikipedia.org/wiki/Biphase_Mark_Code) seems to confirm this. A link "see also ..." on this page might be useful (or an explanation where the difference lies).

Thiadmer Riemersma

I think the Manchester graph is wrong. The correct bits or drawing should be opposite depending on how you look at it. In Manchester Encoding, a 1-bit transits from negative to positive and vice versa for 0-bit.

SA DIP 25 Swl

Actually there are two types of bit representations and the page explains that. To avoid ambiguity, I have specified the type of encoding displayed on the image. Natrij 23:59, 1 February 2006 (UTC)[reply]

I think it's important to note here somewhere that the bi-phase mark (and bi-phase space) are commonly referred to in some industries as FM1 and FM0, respectively. It's an important distinction as FM1 or FM0 (bi-phase mark or space) are easily decoded without reference to (absolute) phase at all. This simplicity exists since a transition occurs at the beginning of each bit period. This stands in contrast to Manchester encoded data where the (absolute) change of phase direction must be noted. FM0 and FM1 as common terms probably came about since they don't imply phase sensitity.

Gene Gajewski 11-Mar-2006 71.32.73.216 04:08, 12 March 2006 (UTC)[reply]

There is an article on Differential_Manchester_encoding as well as one on BMC. That information would probably be more appropriate there. Though I think this article needs a tad more detail about the differential variation and more obvious link -- maybe it's worth putting this nomenclature there as well. I'd advocate the mention of them here in reference to BMC. I believe differential manchester is subtly different again. Maybe we should merge them all into Biphase Encoding or something?--Ktims 22:24, 31 March 2006 (UTC)[reply]

We definitely should have Biphase encoding and Biphase code lead somewhere. Perhaps some merging is in order. Without further study, I'm not clear on the relationship between biphase, Manchester and Differential Manchester. ~Kvng (talk) 13:33, 26 March 2020 (UTC)[reply]

Baseband

Is it worth mentioning that the codes are only useful on baseband mediums, or would that be implicit? It doesn't seem to me that it's entirely clear in the articles on telecoms how modulation and encoding relate to each other. Probably such a change doesn't belong here, but it's where I thought of it...--Ktims 22:24, 31 March 2006 (UTC)[reply]

This is a basic attribute of a line code. There is some discussion of this at Line code#Transmission and storage but improvement there is welcome. ~Kvng (talk) 13:43, 26 March 2020 (UTC)[reply]

Encoding conventions

The difference between the "Thomas" and IEEE conventions is so trivial (inversion of the signal) that its description causes more confusion than illumination. If any conventions are to be compared, perhaps an explanation of "differential" encoding would be more use (if someone can do this concisely). Mike Shepherd 11:36, 12 July 2007 (UTC)[reply]

Manchester code#Conventions for representation of data now seems clear on this. ~Kvng (talk) 13:47, 26 March 2020 (UTC)[reply]

Transformer coupling

I remember learning when I was on an aircraft databus course that this encoding is still (it was a couple of years ago when I was on the course) used whenever devices are transformer coupled on to a databus (or are current rather than voltage sensitive); as it ensures that the signal is constantly alternating. I'll try and do some research/remember it.

Would that be worth adding to the article? 212.17.152.102 (talk) 18:24, 25 August 2009 (UTC) Hibbo[reply]

This is now covered in the second sentence of the first paragraph. It is possible readers may be thrown by terminology: no DC component (constantly alternating) and galvanically isolated (transformer coupled). ~Kvng (talk) 13:51, 26 March 2020 (UTC)[reply]