12/17/21, 4:54 PM
Does using twisted pair wiring make sense only for differential signalling? | Newbedev
Does using twisted pair wiring make sense
only for differential signalling?
OK so the key is in your question, COMMON MODE NOISE...
Consider the following image..
Without twisted pair the line closest to the noise source gets more noise than the other line. So the
noise is no longer common mode.
By twisting the wires you negate, or significantly reduce this effect.
Telephone systems are, or were, all transformer based, which is effectively differential.
So what of single ended..
https://newbedev.com/does-using-twisted-pair-wiring-make-sense-only-for-differential-signalling
1/3
12/17/21, 4:54 PM
Does using twisted pair wiring make sense only for differential signalling? | Newbedev
Well arguably, there is no such thing. You are always passing the difference between something... but I
won't open that can of worms...
In a simple system, you are not only passing the signal but also passing a reference point... usually we
call it ground.. Again. if there is more noise in the signal line than the ground line, that gets picked up
by your receiver.
Of course, that all goes out the window if there is some other ground paths or the grounds are shared
with other signals.
Ultimately, it depends on the application. If it's single ended... where there are only two wires
connecting between each device, and the receiver is battery operated or powered from the
communication line, twisted pair helps a lot. If there are multiple connections or both the transmitter
and receiver signal grounds are grounded locally to the mains... not so much.
In fact, in some instances over-use of twisted pairs can make things worse...
For example, running single ended signals through twisted pair ribbon cable is generally a bad idea.
https://newbedev.com/does-using-twisted-pair-wiring-make-sense-only-for-differential-signalling
2/3
12/17/21, 4:54 PM
Does using twisted pair wiring make sense only for differential signalling? | Newbedev
The fact that you are bringing your signal wire closer to the neighboring signal wires increase the
cross coupling between them. It is better to use a standard flat ribbon cable with ground wires
between each signal acting as a kind of shielding.
Tags: Twisted Pair
Related
PCB equivalent of wire twisting
When should twisted pair wires be used?
Recent Posts
Pandas how to find column contains a certain value
Recommended way to install multiple Python versions on Ubuntu 20.04
Build super fast web scraper with Python x100 than BeautifulSoup
https://newbedev.com/does-using-twisted-pair-wiring-make-sense-only-for-differential-signalling
3/3