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Re: [10GBT] Channel models


FEXT measurements between two pairs are symmetrical regardless of which pair is the transmit (disturbing) pair and which pair is the receiving (disturbed) pair.  ELFEXT calculations can be slightly different due to attenuation/insertion loss variances between the cable or cabling pairs.

Hope this helps.  - Val

Sanjay Kasturia <SKasturia@TERANETICS.COM>
Sent by: stds-802-3-10gbt@IEEE.ORG

05/12/2004 04:38 PM
Please respond to "IEEE P802.3an"

        Subject:        Re: [10GBT] Channel models


Good question. I assumed that FEXT between pair i and j would be the
same as between j and i. Thinking about it some more, I am not sure if
that is correct. Can others let us know what measurements have revealed?

Chris DiMinico, can you answer this?

cell (650) 704-7686
office (408) 653-2235

-----Original Message-----
From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On
Behalf Of Sparrowhawk, Bryan
Sent: Wednesday, May 12, 2004 4:19 PM
Subject: Re: [10GBT] Channel models

I have a question about your terminology regarding far end crosstalk in
Could you have meant twelve pair combinations for FEXT instead of 6?
Or do you speak of "Far end crosstalk" as others speak of 'reverse
Bryan S.

-----Original Message-----
From: Sanjay Kasturia [mailto:SKasturia@TERANETICS.COM]
Sent: Friday, April 09, 2004 3:36 PM
Subject: [10GBT] Channel models

We have four channel models defined from the March 2004 plenary meeting.

For detailed PHY performance simulations, we will need sample channel
data that complies with these models.

We will greatly appreciate it if any task force participants can provide
full matrix (4x4) channel data. This would ideally include:
a) Insertion loss data on each of four pairs - real and imaginary
b) Near end crosstalk coupling (6 unique pair-combinations) - real and
c) Far end crosstalk coupling (6 unique pair-combinations) - real and
d) Four unique echo transfer functions (one for each pair) - real and

This can be obtained by measurements on actual cable and then scaling to
meet the specified channel models.
Any cable companies volunteering to provide this data?

There is some data from the cabling Ad-hoc available on:
This data has some of the items listed above but not all. It does,
however, provide enough to get some sense of performance.

Sanjay Kasturia
cell (650) 704-7686
office (408) 653-2235