I also looked at this for long LVDS on printed flex cabling and the
effect was marginal. This was not a full twist (utilizing vias) but rather
superimposed snaking traces on a thin base material. Instead we opted for
controlled impedance traces grouped to minimize cross talk or isolated with
guard traces. The only place I've used this with appreciable benefit is in
minimizing magnetic signatures in sensitive instruments, and there the
primary benefit was to reduce the number of areas to calculate and sum.
John
Jon Elson wrote:

> Cam Andruik wrote:
>
>      Has anyone ever tried to fake creating a twisted-pair on a
>      PCB?  I tried
>      doing so on a recent board and our testing indicates that it
>      did nothing.  I
>      think it is a waste of time to even attempt it but some people
>      here think it
>      is helpful.
>
> I did this on one board that had analog differential signals right next
> to
> 10 A, 80 V pulses with 40-100 nS Tr.  It probably works, as there was no
>
> measurable crosstalk on the analog signals.  I didn't however, make the
> board
> both ways and compare.  I wouldn't even bother with two comparable
> low-level
> signals.
>
> Jon

--
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>John M. Cardone       Electro-Mechanical Dsgn. Engr. Grp.
>M/S 278-100           Mechanical Engineering Section, 352
>4800 Oak Grove Dr.    NASA / Jet Propulsion Laboratory
>Pasadena, Ca 91109
>Tel: 818.354.5407     MailTo:[EMAIL PROTECTED]
>Fax: 818.393.6400     Cell: 818.653.7818
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>



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