[SI-LIST] Re: Series termination greater than the characteristic impedance?

Whether crosstalk impacts the impedance of the trace depends on the 
degree to which the two signals are correlated. If there is no 
correlation (i.e. the two signals are randomly distributed compared 
to each other) there is no impact. In the limit, with perfect 
correlation, we have one of two cases:
(a) differential impedance-type impact (Z = Zo - Z12) if the 
correlation is perfect and negative, or
(b) Common mode (Z = Zo + Z12) if there are perfectly positively correlated.
Z12 depends, among other things, on the coupling coefficient between 
the traces.

Doug



At 08:48 AM 1/17/2006, Grasso, Charles wrote:
>Crosstalk can dramatically affect the impedance of a trace.=20
>Under certain conditions the impedance will INCREASE and under
>other conditions the impedance will DECREASE from the desired value.
>

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