[sdiy] twisted pairs?

[David G. Dixon]

I'm not sure about the theory, but wrapping signal wires with ground wire in
one of my circuits virtually eliminated the noise that the signal wires were
broadcasting to the rest of my circuit.  However, I was careful only to
ground one end of the ground wire; the other end was unconnected.  I don't
know if this matters or not.

Since then, I've taken to running ground leads from PCBs to panel pots,
rather than running ground wires from pot to pot on the panel, just so I can
twist the ground wires around the others.  Maybe I'm deluding myself, but it
makes me feel good.


David G. Dixon
Professor
Department of Materials Engineering
University of British Columbia
309-6350 Stores Road
Vancouver, B.C.  V6T 1Z4
Canada
 
Tel 1-604-822-3679
Fax 1-604-822-3619
 
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-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of George Hearn
Sent: Monday, December 01, 2008 2:13 AM
To: synth-diy at dropmix.xs4all.nl
Subject: RE: [sdiy] twisted pairs?

Twisting two wires together and running them through the instrument together
means (in theory) that both wires will experience the same pickup of noise
and interference.  By taking the differential between the two wires at the
receiving end one is able to reject the common mode signal (the noise).  In
my opinion, twisting a ground wire with your signal is not likely to do an
awful lot and you'd be better off just using the ground as a shield.  George

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of John Mahoney
Sent: 29 November 2008 16:03
To: Dan Snazelle; sdiy
Subject: Re: [sdiy] twisted pairs?

At 07:49 AM 11/29/2008, Dan Snazelle wrote:


>i was reading in the art of electronics that an ordinary twisted 
>pair can reduce some digital clocking noise.
>
>i was wondering if all this is is twisting a wire connected to 
>ground with the wire you are trying to protect?

Yes, I believe that's it.

John 

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