Common mode, differential mode: Difference between revisions
mNo edit summary |
mNo edit summary |
||
Line 108: | Line 108: | ||
===Perhaps-necessary clarification=== | ===Perhaps-necessary clarification=== | ||
====Distinction between common mode, differential mode, single | ====Distinction between common mode, differential mode, single ended==== | ||
<!-- | <!-- | ||
Line 121: | Line 121: | ||
Single | Single ended means a signal is present on one wire and not another | ||
: which seems to describe common-mode reality | : which seems to describe common-mode reality | ||
: but can also be true in differential | : but can also be true in differential |
Revision as of 12:51, 17 September 2023
Common mode versus differential mode is about communicating a signal electrically, usually as a voltage signal.
Theoretical side
Common mode
Common mode signalling points at a situation where you have
- a reference conductor, which both ends of this communication have in common
- often called "signal common".
- a conductor for a signal
And the signal is the voltage difference between the two.
Differential mode / differential signalling
Perhaps-necessary clarification
Distinction between common mode, differential mode, single ended
Differential in more depth
Single ended
Single-ended signalling basically means all the signal is on one wire, none on any other.(verify)
A lot of the time, single-ended is used as a near-synonym for common mode.
And fair enough, common mode basically implies single ended, in that there is typically a signal common, used as a reference for one or more signals, which is usually tied to some fixed level (like ground).
Yet single-ended does not necessarily imply common-mode reference.
While introductions to XLR make a big kerfuffle over sending signal/2 and -signal/2 on the two wires, it is entirely valid to send the signal on one wire and nothing on the other (which you'd easily call signle-ended), because after differential interpretation this implies the same signal at the other end and the same amount of noise reduction.
In fact, doing this is moderately common(verify) because it is a little simpler component-wise.
If a distinction is made between single ended and common mode, single-ended often refers more to the concept, common mode more to electrical reality of conductors.
Both single-ended and common mode are mainly contrasted with differential mode
Practical side
Balanced audio / pro audio
See Music_-_studio_and_stage_notes#Notes_on_balanced_audio
Comparisons
See also