FreeLists / si-list / [SI-LIST] Re: Differential vs. SE, Propagation speed comparison

[steve weir <weirsi@xxxxxxxxxx>]

Chris, for surface microstrip this can be true since the signals are 
complementary, more of the field remains in the air between the two traces 
than does for an isolated single-ended line of equal 
impedance.  Consequently, the average Er is lower and the propagation 
velocity is higher.  Dr. Bogatin ( www.bethesignal.com ) has a nice 
write-up on this phenomenon in his book "Signal Integrity Simplified"  He 
also has a class coming up in May in the Bay Area.

Steve
At 03:53 PM 4/7/2005 -0400, Chris McGrath wrote:

>I just read in an app note that "differential signals have a faster
>propagation time than single ended signals".
>
>I have played around with some simple simulations and can produce some
>scenarios where this seems to be true, but I'm having a problem
>understanding the physics of why this should be.  Can anybody shed some
>light on this?
>
>Thanks,
>Chris
>
>
>------------------------------------------
>Chris McGrath
>Sr. Hardware Engineer
>ADIC
>ph: (607) 241-4858
>eM: chris.mcgrath@xxxxxxxx
>------------------------------------------
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