Re: [10GBT-Modeling] RE: [10GBT-Cabling] [10GBASE-T] a channel capacity esti...
I've asked Brad to post a paper I presented at the International Wire and
Cable Symposium in regards to the
development of equal level far-end crosstalk (ELFEXT) and return loss
specifications for Gigabit Ethernet
operation on category 5 copper. It will address some of the background
questions and provide
some insight into the development of the cabling parameters and limits
specified in 1000BASE-T.
As I mentioned earlier, the measured cabling models were generated by Bob
Cambell and I. They are illustrated in the
1000BASE-T tutorial presentation (3/97) titled Category 5 Cabling Models For
Line Code Simulations.
A significant amount of effort went into the evaluation and specification of
cabling for 1000BASE-T
operation. It is true that many of the individuals involved with the line
code development did not participate
in the cabling specification development.
In a message dated 2/27/03 4:59:51 PM Eastern Standard Time,
I believe the 100MHz came from the TIA specifications. In fact, in the
early days I remember checking the channel capacity over the 100MHz Bandwidth
(for sanity check) on my own and realized that there is a nice healthy
capacity margin above 1Gbps, therefore no need to even bring up the issue.
Vivek Telang wrote:
> Sreen is right. The simulations for 1000BASE-T all used Cat5 modeling
data. The only exception was that for FEXT, we used models provided by Chris,
and the other cable guys. These FEXT specs were later ratified in the Cat5e
spec. Also, the simulations used data that was specified out to 100MHz. I
don't quite remember if the "official" Cat5 standard supported this, or
whether the 100MHz data also came from Chris et al.
> Vivek >>