Talk:Differential Manchester encoding

message: I am fairly certain that the term Conditioned DePhase is incorrect and should be Conditioned Diphase as per FED-STD-1037C.
I am changing the article to make this correction.
Peizo (talk) 19:44, 6 September 2008 (UTC)

message: : There seem to be several slightly-different line codes, all of which would work with a decoder that decoded "transition in the middle of the bit-time" (hi-lo or lo-hi) to 0, and "no transition for the entire bit-time" ( hi-hi or lo-lo ) to 1.
: This category includes coded mark inversion, the 2-level version of "Return-to-zero in optical communication", and differential Manchester encoding.
: The difference between them is in the details of how the transmitter chooses whether or not to add another transition between bits.
: When the transmitter *always* adds a transition between bits, it generates differential Manchester encoding.
: When the transmitter *never* adds a transition between bits (always maintains the previous level), except it always adds a transition between 2 consecutive 1 data bits -- is there a name for this kind of line code?
: --68.0.124.33 (talk) 06:59, 27 July 2008 (UTC)
replies: text:  I think that's NRZI. Mark.sullivan (talk) 17:41, 11 July 2015 (UTC)
thread_title:  yet another slight variation 

message: ...a high speed variation on the Kansas City Standard, or to be more precise, 1200 baud CUTS?
Or maybe they're a slower variant on this, depending which came first.
If you see it in terms of an audio wave, a 0 is being encoded as two cycles of a high frequency master clock, and a 1 as a single cycle of a wave at half that frequency. Which is exactly how CUTS works (KCS quadruples up the number of cycles for a more reliable 300-baud). Presumably there may also be provision for a carrier signal at 4x the 1-code rate or similar... ;) 193.63.174.10 (talk) 13:40, 25 September 2010 (UTC)
thread_title:  isn't this just... 

message: I don't think "Coded mark inversion" is a differential coding example, as 0 always means positive transition -- JohanDeGaule (talk) 17:26, 28 July 2011 (UTC)
thread_title:  Differential coding examples. 

message: The first image is wrong: if "data" row is still not differential-encoded, then the result should be:
DATA	DIFF.ENCODED	CURRENT	CORRECT
1   	xx          	10     	xx
0   	1           	10     	10
1   	1           	01     	10
0   	1           	01     	10
0   	0           	01     	01
1   	1           	10     	10
1   	0           	01     	01
1   	0           	10     	01
0   	1           	10     	10
0   	0           	10     	01
1   	1           	01     	10
(we cannot know the status of the first bit because we cannot know the state of the previous one)
I point out that "differential manchester" row would be wrong even if we assumed "data" as already differentiated. 
The second image (BMC) could be correct. But "DATA" refers to already differentiated data, where "0" means change between bit k and bit k-1 (usually 1 means change between one bit and previous one). Additionally, the whole line should be shifted half a bit to the right.
So I suggest to leave only one image and add the "differential encoded" line, in order to make it more clear. I can do this as far as I have time to do it, but I'd like to listen to some opinions before doing it.
Vito
:Hi Vito, you assumed that differential Manchester encoding means Manchester encoding of differentiated data. It is only the receiver that differentiates. The line signal can be interpreted as a sequence of (Manchester-II) symbols 01 and 10 (rising and falling edges where the edges are unconditional). Differentiating that sequence yields the data. --Rainald62 (talk) 20:50, 24 December 2016 (UTC)
thread_title:  Problem with images 

message: In the example graph, the voltage level starts out at 0V then begins transitioning between a positive and a negative voltage. The voltage at the end is 0V. I believe that the part of the signal where it is pictured at 0V should not be shown. When the signal transitions between a positive and a negative voltage, it would never stop at 0V. It would just pass through 0V on its way to the opposite extreme.  — Preceding unsigned comment added by 76.179.72.64 (talk) 23:39, 11 April 2012 (UTC)
thread_title:  Problem with the example graph of differential Manchester 

message: Hi, are we sure that the first image is correct?
In my opinion it should be different when data are 1 continuously (as in the image, it loses clock!).
Thanks,
Marco from Italy  — Preceding unsigned comment added by 95.208.187.225 (talk) 16:54, 13 November 2012 (UTC)
thread_title:  Possible error 

message: The example image is still confusing as the graph contradicts the description.94.214.169.209 (talk) 06:30, 18 April 2016 (UTC)
thread_title:  Confusing example 

message: I think Frequency modulation encoding should be merged into this article. This has already been discussed to some extent at Template:Did you know nominations/Frequency modulation encoding and Talk:Frequency modulation encoding#Feedback from New Page Review process, where article creator Maury Markowitz has claimed that FME should be a separate article because it describes this encoding only in the specific context of floppy disks, but I am unconvinced that that specific context is separately notable and I don't think the article itself clearly articulates any such clear distinction. —David Eppstein (talk) 17:18, 8 June 2022 (UTC)
replies: text: There was some additional discussion on the relationship of these terms at Talk:Modified_frequency_modulation#Frequency_modulation_vs._Digital_frequency_modulation involving some knowledgeable editors on this topic that you might want to WP:PING. ~Kvng (talk) 15:20, 11 June 2022 (UTC)
thread_title:  Merge from Frequency modulation encoding