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[10GMMF] TP3 meeting notes Oct 19: Comments and corrections from Tom Lindsay.

Hi TP3ers,
Please see comments and  corrections from Tom below.
Thanks Tom: It is good to see my notes do get read!
Best Regards
----- Original Message -----
Sent: Wednesday, October 20, 2004 6:12 AM
Subject: [10GMMF] TP3 meeting notes Oct 19

Dear TP3'ers,

Here are my notes from yesterday's meeting. Any comments or corrections please let me know.

Next Meeting:-

Tuesday October 26th at 9am SJ, 5pm UK, 6pm Germany
Dial in (650) 599-0374, Meeting ID:     136169

1. List Attendees

Aronson, Lew
Dawe, Piers
Ewen, John
Hanberg, Jesper
Latchman, Ryan
Lawton, Mike
Lindsay, Tom
McVey, Jim
Popescu, Petre
Shanbhag, Abhijit
Telang, Vivek
Van Schyndel, Andre
Weiner, Nick
Witt, Kevin

2. Review meeting notes from last week
No comments

3. Review Lew's additional motions (which were not heard at Ottawa). These were forwarded by Lew last week.
Lew described the motions he did not get to present in Ottawa

This one presented more details around the parameters used in the stressed Rx sensitivity test, namely:-
        i)   set OMA max (shown as -6.6dBm  but due to change as dynamica adapation penalty was not voted out)
        ii)  Sinusoidal Jitter freq and amplitude (40MHz, 0.1UI)
        iii) remove reference to sinusoidal noise term
        iv)  add reference to OSNR figure (TBD) to represent noise powers

i), ii) and iv) did not get much discussion. I assume that is because there is broad agreement on these.
TAL - did you mean iii) instead of ii)?  
MCL Yes. Apologes my error.  

For ii) there was a discussion about how jitter is represented in our stressed test. Clearly jitter contributions come from several different sources (Tx clocks, tx circuitry, channel impairements ...) The group discussed which are the significant sources for jitter and hence how it should be represented in our test. Our repesentation of the channel ISI will create some jitter but we need to understand if this is sufficient or if there are other significant sources of jitter (with potentially different characteristics) which need to be represented in the test.

ACTION: Petre kindly agreed to evaluate the jitter testing required and consider the need for a high frequency sinusoidal interferer.

Tom has already helped here with an email to the reflector.

Adopt methodology in line with 52.9.5 for OMA measurement
In particular:-
        i)   for TP2 use the 4 "1"'s 4 "0"'s pattern defined within 802.3ae
        ii)  for TP3 use the same technique with a 10 "1"'s and 10 "0"'s pattern
        iii) Calibrate OSNR with the same singal as in ii)

Petre asked if there was value in developing a technique which could be supported more easily in the field. The current approach is assuming that this is not a requirement.

Piers raised the accuracy and the usability of the 1's and 0's method vs a histogram approach. Adding that he sees subtle differences between a 4 "1"s and "0"s vs a 10. He asked that we allow him to progress this work further.

The group gave its support to this motion but is happy to listen to recommendations to improve the accuracy/usability of the OMA measurement.
TAL - this reminds of earlier discussions regarding the dynamic penalty. Here, we want the best balance of an accurate test (one that links to the budget and interoperability) and one that is that is easy and versatile. If we can get both, then we've won. Otherwise, I tend towards accuracy, especially when the budget is tight - we don't have a lot of room for slop and sandbagging.
Although I favor Lew's approach, this comment should not be interpreted as reading against Piers's work on this. Hopefully he can come up with something that indeed does it all.
I recall that we do all generally agree on the conceptual definition of OMA that we're using. That is important for budgeting, analysis, etc. Testing can stray a bit away from that as long as we have an accurate way to associate back to the budget.

This one is not directed at the standard directly but more attempts to provide a framework for advancing the ISI portion of the test.
Lew offered the following:-
        i)   we should pursue using a set of 3 different chanels for testing (pre, post curson and quasi symmetric)
        ii)  we should define a "goodness of fit" metric (PSR) for a 5 impulse peaks model, each with uniform time spacing
        iii) Not use PIE-L but focus on PIE-D
        iv)  Assume Tx rise/fall times of not less than 4 7 ps

i) was not heavily discussed.
ii) was discussed. A counter view was expressed that maybe we could describe minimum tap weightings and minimum PIE-D's for an exact channel and let the implementer decide his exact channel implementation
iii) the debate has moved on since the motion was presented. There were some concerns presented around PIE-D as a metric arguing it has limitations in terms of representing a finite length equaliser. A metric relating to finite equalisers would be valuable.
TAL - we did not get to it, but this last thought was added also to my revised TP2-TP3-budget presentation. It came up again on the TP2 call today, and there seems to be some growing support for it.
iv) some confusion around rise/fall times. Lew wrote this to be relax the rise/fall time burden on the equipment used for the test. That said it may end up being important that we relate this figure to what TP2 says about rise and fall times.
TAL - I will try to respond to this in a separate email.

4. TP2/TP3 link budget work. Tom Lindsay's Feedback from TP2 call
Ran out of time before this item

Upcoming items of focus (for subsequent metings):-
          i)  Jitter requirements
        ii) Static channel methodology
                - noise loading
                - channel types and exact characteristics
                        o i.e. do we pick pre, post cursor and quasi symmetric and if so where from? 108 fiber model?
        iii)OMA measurement methodology.

Best Regards