[SI-LIST] Re: Why shielded twisted-pair is still twisted?
- From: earl albin <earlalbin@xxxxxxxxx>
- To: Neo <neoflash2008@xxxxxxxxx>
- Date: Sat, 15 May 2010 09:53:05 -0700
I get it, trick question. A magnetic field inversely proportional to the
square of the distance will induce a differential current into the wires
because one wire is closer. Twisted makes the wires on average the same
distance, same thing with an e-field. Another trick question, the external
shield works for an e-field but not the h-field unless it's feromagnetic.
Got a signal generator, a scope, some wire, some time. Figure it out.
On Mon, May 10, 2010 at 3:41 PM, Neo <neoflash2008@xxxxxxxxx> wrote:
> Hi,
> I'm thinking about why shielded twisted-pair is still twisted?
> Pair is twisted for controlled distance/impedance (due to twist) and for
> x-talk reduction. If a pair is already shielded together, it is not
> necessary to twist them any more.
> Without twist, it will be equivalent to twin-ax cable, isn't that better?
> Thanks,Neo
>
>
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