Talk:Non-return-to-zero, inverted

This and related articles should have diagrams. I will make them eventually if no one else does. - Omegatron 16:28, Nov 2, 2004 (UTC) "Lets" should be spelled "let's". It's a contraction. 4.234.249.153 15:17, 10 February 2006 (UTC)

Mistake in figure?
To my opninion, I'm just a student 'though, the NRZI-code knows a transition when there is a logical "1" and no transition when there is a logical "0". Correct me if I'm wrong. Kind regards...
 * Just FYI, CDs at least do it that way. So I've added the clarification. I don't know about USB and ethernet, though. --Klaussfreire 20:18, 7 September 2006 (UTC)
 * USB uses 0=transition (I checked the spec). So that's at least one thing that works as described by the article. Mirror Vax 22:18, 7 September 2006 (UTC)
 * According to this web site, http://www.interfacebus.com/Definitions.html, the definition of NRZI is, "A '0' is encoded as no change in the level. However a '1' is encoded depending on the current state of the line. If the current state is '0' [low] the '1' will be encoded as a high, if the current state is '1' [high] the '1' will be encoded as a low. Used with FDDI and USB for example." It comes with timing diagrams too. That was the way I learned it in the HDDR recording business. --Luenlin 21:31, 19 September 2006 (UTC)
 * I agree there is disagreement between the figure and the context. The context stated there are transitions for every '1's. The figure implies there are transitions for every '0's. I think the figure is wrong. --Luenlin 18:49, 3 November 2006 (UTC)
 * The USB 2.0 Specification states that a 0 is represented by a transition, and a 1 is represented by no transition. The wiki page is incorrect --jsynnott, 16 November 2006
 * According to Data and Computer Communications (Stallings, William) http://vig.prenhall.com/catalog/academic/product/0,1144,0132433109,00.html, a transition denotes a 1. Jgiam 12:37, 26 November 2006 (UTC)

Why use NRZI?
Could someone add a bit on why this method is useful and what problems it is designed to solve? Rearden9 17:43, 1 August 2006 (UTC)
 * The advantage of NRZI modulation is it only needs a maximum of one transition per bit in encoding the data, compared to other encoding schemes. This provides a “reduction of bandwidth” in recording/transmission and reproduce/reception electronics to handle the data flow. --Luenlin 19:30, 3 November 2006 (UTC)

Article Deletion, NRZI allready under NRZ
Non-Return-to-Zero Inverted is the same with Non-Return-to-Zero Inverse which is one of the 4 variants of Non-return-to-zero and detailed under its article. This article shoule be deleted--Mancini 08:55, 21 November 2006 (UTC)


 * Prod opposed. This article has information (who uses it) not present in NRZ. I suggest merge.
 * However, a more dramatic problem is that I think this article's flipped its sign bit; NRZ is transition-on-one; NRZI is transition-on-zero, last time I checked. This article has its text and figures all saying transition-on-one. --Alvestrand 07:19, 27 November 2006 (UTC)
 * As I mentioned above, Data and Computer Communications (Stallings, William) http://vig.prenhall.com/catalog/academic/product/0,1144,0132433109,00.html says it is transition-on-one. Jgiam 13:51, 27 November 2006 (UTC)

What?
I can't actually find the part that tells you what NRZI is. There's loads of bollocksy stuff I can't understand so I guess it's there somewhere, but it would be nice to have a simple sentence saying "The polarity of the bits is inverted each time a 1 is encountered" or something like that.