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Forwarded on behalf of Albert...
George,
The time-domain
bench has the AWGN on the receiver side, whereas
the sine interference was
injected at the xfromer side. No ANEXT
was employed at that time -- it would
need to be applied at the
MDI, when considered.
The line background
noise (as a dissipative physical system at ~300 K)
is assumed negligible
w.r.t. the IC noise and cancellation residuals
referred to the receiver
input.
Regards,
Albert
George Zimmerman
wrote:
Albert -
So are you assuming that the entire AWGN component occurs on the
receiver side of the line transformer, or does a portion of it pass
through the line transformer as well? (which ANEXT or background EMI on
the channel would do.)
-george
-----Original Message-----
Sent: Thursday, August 05, 2004 10:45 AM
Subject: Re: [10GBT] PAM8 and PAM12 sys time domain analysis
Sailesh,
When the line transformers (specified roughly as per
presentations the group has seen so far) are included in the
analysis -- the channel shows additional ~5.6 dB of loss at
500 MHz. See attached graph.
This, combined with Tx 1 Vp launch constraint at the IC, but
not at MDI, accounts for the bulk of SNR losses w.r.t. "ideal"
Class E channel Salz SNR.
The actual SNR loss in the time-domain bench vs. its frequency
domain reference proves to be below 1 dB -- this would be a very
hard target to achieve for any practical h/w implementation of
10GBASE-T.
Regards,
Albert
sailesh rao wrote:
Albert,
I assumed that the reference to Model 3 in your report included ANEXT
with a
64.5dB intercept and other worst-case impairments, as agreed upon in
the
task force.
If there was no ANEXT or residual Echo/NEXT/FEXT in your simulations,
then I
calculate the implementation loss in your simulations to be at least
3.6dB
for PAM8 and at least 4.0dB for PAM12.
I don't think we should be contemplating such implementations for
10GBASE-T.
Regards,
Sailesh Rao.
srao@phyten.com
From: Albert Vareljian <albertv@IEEE.ORG>
Subject: Re: [10GBT] PAM8 and PAM12 sys time domain analysis
Date: Fri, 30 Jul 2004 00:20:13 -0700
Hi Jose,
No ANEXT or other impairments except -140dBm/Hz were employed in sims
covered in the report.
Adding ANEXT would seem to be the next logical step. However,
correctly
modeling ANEXT may prove a bit tricky.
As we already discussed on IEEE floor -- our agreed ANEXT models
are specified only in terms of the frequency domain magnitude (no
phase). So, the time-domain implementation has been left open up
to the user...
There could be many interpretations as to how one arrives at a
reasonably behaved time-domain ANEXT TF and its excitation method.
Our analysis indicates that end results in the system could vary
significantly on the case by case basis, depending on the methodology
used to model time-domain ANEXT behavior.
Based on the above, it may be helpful if the group agrees on and
adopts
some "uniquely" defined causal, scalable time-domain capable model
for ANEXT that could be used for system qualification. One possible
example of ANEXT TF implementation in s-domain (usable in time- and
frequency- sims) is illustrated in the attachment.
Regards,
Albert
Jose Tellado wrote:
Hi Albert,
Thank you for your detailed time-domain report, I have a couple of
simple questions on the simulation assumptions.
Have you included the effects of ANEXT in these simulations? If so,
what
approved PHY channel model (1-4) would this approximate?
Did you include other receiver impairments such as residual EC/NX/FX
or
did you lump all these effect into the -140dBm/Hz noise?
Regards,
Jose Tellado
-----Original Message-----
Sent: Monday, July 26, 2004 7:57 PM
Subject: [10GBT] PAM8 and PAM12 sys time domain analysis
Hi All,
Pls find attached pdf report on PAM8 and PAM12 systems time domain
simulation and comparative analysis.
Regards,
Albert Vareljian
<< ANEXT_Fig.doc >>
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