You are right,
Jose. I used the 55m cat 6 case because that was what the presentations
were pitching as the best case for PAM4 – the situation IS even worse for
longer lines, or worse for high frequency ANEXT.
By the way, Figure 7
is the one you want to look at to see the plots with the crossover of ANEXT
& IL.
Jose, I think you
meant the 100m models for Class F IL & Class E IL respectively, models 1
and 3 (2 is the 55m model).
To see the results
for Model 1 (Class F IL, Class E other params, 100m, 60 dB ANEXT at 100MHz),
run: solarsep_varlen7a(-2.5,650,4,100,6,1,7,2)
To see the results
for Model 3 (Class E IL, Class E other params, 100m, 62 dB ANEXT at 100MHz),
run: solarsep_varlen7a(-4.5,650,4,100,6,1,6,2)
-george
-----Original
Message-----
From:
stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On Behalf Of Jose Tellado
Sent: Tuesday, May 11,
2004 3:45
PM
To:
STDS-802-3-10GBT@LISTSERV.IEEE.ORG
Subject: Re: [10GBT] Symbol
rate
I think the case
you considered below is for 55m of cat6. The problem is even worse for
100m of channel model 1 or model 2 (see http://www.ieee802.org/3/an/public/mar04/kasturia_2_0304.pdf),
where the SNR "pinching" happens around 500MHz,
Jose
From:
stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On Behalf Of George Zimmerman
Sent: Tuesday, May 11, 2004 3:19
PM
To:
STDS-802-3-10GBT@LISTSERV.IEEE.ORG
Subject: Re: [10GBT] Symbol
rate
At the March meeting,
some of the discussion on leaving the door open to the higher baud rates was
aksing to have time to run simulations with the higher baud rates to validate
the optimal DFE results presented.
The MATLAB code has
been available on the 802.3an web site for a while now – I assume others have
now seen that the ANEXT model we agreed to (49.5-15log10(f/100)) is within a
couple dB of the insertion loss at 650 MHz – which means that the penalty for
signaling at rates over 500 MHz, where the SNR gets pinched off, is extreme.
(to run this case, use: parameters: solarsep_varlen7a(-10.5,650,4,55,6,1,6,2)
).
What these curves
tell you is simply that at more than 1Gbaud, you are simply signaling faster
than the channel can support, and thus starting out in an SNR hole in building
a 10GBASE-T system.
Hopefully at the
meeting we can agree to constrain the baud rates and begin to focus our
analysis.
-george
-----Original
Message-----
From:
stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On Behalf Of Booth, Bradley
Sent: Tuesday, May 11, 2004 10:36
AM
To:
STDS-802-3-10GBT@LISTSERV.IEEE.ORG
Subject: Re: [10GBT] Symbol
rate
The objectives do
require that we provide one PHY that meets at least 100 meters on Class F
and at least 55 to 100 meters on Class E. A proposed PHY must meet both
these distance requirements. To take this a step further, a PHY or port
type has traditionally referred to one PCS, one PMA and one PMD. So this
could be seen as one PHY which has only one PCS, one PMA and one PMD is
required to meet both the distance objectives.
In the past, the
Working Group has asked the Task Forces to make the tough decisions and to
choose only one PCS, PMA and PMD to meet the objective. If the Task
Force chooses PAM5, then the decision is made. If the Task Force chooses
PAM10, then the decision is made. If the Task Force chooses PAM5 and
PAM10, then the Working Group will likely send the specification back to us to
make a decision.
To quote the movie
Highlander, "There can be only one."
-----Original
Message-----
From:
stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On Behalf Of Sanjay
Kasturia
Sent: Tuesday, May
11, 2004 12:12 PM
To:
STDS-802-3-10GBT@LISTSERV.IEEE.ORG
Subject: [10GBT] Symbol
rate
At the March
meeting, there was a motion to bound the range of symbol rates. The motion,
moved by George Zimmerman, suggested a symbol rate that would range
from 714Msym/sec per pair to 1000Msym/sec per pair.
This motion failed
to get the requisite 75% yes vote. Some of the people who voted against
this proposal were in favor of schemes that would require higher
symbol rates - e.g. 1250Msym/sec per pair but were probably not very
familiar with 802.3 operation. With 802.3 voters in the room, the
motion would have passed. See the vote tally appended below from the meeting
minutes.
As I understand it,
the PAM 4 type schemes that would use the much higher symbol rate
would NOT meet our distance objectives but offered some value in that
they could enable much lower power transceivers for shorter distances than
called for in our objectives.
Should these
schemes, which do not meet our distance objective, but could still be
valuable for customers who want shorter reach and lower power be considered
in separate class - possibly in a different forum than
802.3an?
Can our chair, Brad
Booth, give us his opinion on this?
Vote count from minutes of March
meeting
TF Voters Y: 24 N: 15 A:
19
802.3 Voters Y: 21 N: 5 A:
9
Sanjay
Kasturia
Editor-in-chief
sanjay@teranetics.com
cell (650)
704-7686
office (408)
653-2235
Teranetics
Inc.
2953 Bunker Hill Lane, Suite
204
Santa Clara, CA
95054