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[10GBT] Request for Cat6 Emissions Characteristics



Hi All,

At the request of a task force member, I computed the transmit PSD for PAM8,
PAM12 and 1000BASE-T, and discovered that I added the contribution of Jose's
0.4dB incorrectly in my Total EMI Penalty calculations in the updated table.
Actually, in the passband, the transmit PSD for PAM8 after THP is 1.6dB
lower than the transmit PSD for PAM12 after THP, and not 0.8dB lower as I
had reported earlier.

However, rather than simply adding another 0.8dB to the PAM12 EMI penalty, I
would like to propose that we compute the estimated emissions
characteristics of the PAM8/PAM12 transmit PSDs, for different transmit
filtering choices, over typical Cat6 cabling and assess the difference in
peaks to estimate the true emissions penalty for one PAM approach over the
other. I know Scott Powell had published a PDF version of measured
4-connector Cat6 emissions characteristics for a flat transmit PSD
(powell_1_0303.pdf), but do cabling experts agree with Scott's measurements
and can the task force use that data to assess the emissions characteristics
of PAM8 vs. PAM12? If so, I would like to request Scott to publish a file
version of his measurements on the task force web site so that we can all
use it to do fair comparisons. If not, are there other typical Cat6 cabling
emissions measurements that we can use to do the emissions comparisons?

Any input from the cabling experts on the reflector would be greatly
appreciated.

Regards,
Sailesh Rao.
srao@phyten.com

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