Signaling ad-hoc (December 3, 2004)
Mike Altmann opens the meeting
going over the Agenda ( http://ieee802.org/3/ap/public/signal_adhoc/altmann_s1_1204.pdf
) and continues reviewing deadlines and dates agreed upon at the San
Antonio plenary meeting and gives an update on the Signaling Spreadsheet
(slide #6). Changes to the spreadsheet are outlined on slides #7 and #8
and after reviewing them, Mike introduces a list of proposed straw polls
(slide #9, #10) which will be used to finalize the spreadsheet. The floor
is opened for discussion.
[Fulvio]
Would
it not be better to discuss these changes in the context of the straw
polls listed on slides #9 , #10 ?
This is agreed and the
discussion begins on the first straw poll : “Should we fix a required data
pattern?”
[Joe
A.]
We should have at least a common data pattern. This should be a long
pattern since the best way to simulate crosstalk is to have long patterns
with frequency offsets.
[Mary
M.] Short patterns
are misleading …
[Jeff
S.]
Spectrum of short patterns is to sparse to effectively evaluate a channel.
PRBS15 is a nice compromise in terms of frequency resolution and
simulation length
[Charles
M.] When we use the same data sequence to
compare NRZ and Duobinary it seems clear what it is that I am doing. The
same is not true when we compare PR4 and PAM4. I also would like to
specify the pattern before mandating that we need to have a common
pattern.
[Mike
A] Maybe
we should ask what is the max simulation length that we can deal with.
Also should these PRBS sequences be coded or
uncoded?
[Charles M.] I do not think that the encoding is necessary
[Brian]
Do you want to establish BER capabilities ?
[Mike
A.] We have
decided to report timing and voltage margin at three different rates. How
we compare the BER may have some bearings on the PRBS pattern. My
preference is to use short patterns because most of the channel response
are limited to 10 to 15 UI. Eye diagrams obtained from simulating longer
patterns would not necessarily differ.
Straw poll
1: Should we
fix a required data pattern?
passed by acclamation: (20 people on the call)
The discussion resumes on
straw poll #2 : “What forward channel
data pattern should we simulate with as a common data
pattern?”
[Jeff
S.]
is this also the crosstalk pattern?
[Joe
A.]
that is my point: simulation length and pattern go
together.
[John
d'Ambrosia] did we not
specify the aggressors to be the same as the
main?
[Fulvio]
no, just the equalization characteristics.
[Joe
A.]
… but if you take them to be different then you are saying that the
pattern is really no representative. I would like to see the same pattern
for the forward path and for crosstalk..
[Mike A. ]
is there any other
candidate we want to add to the list of potential
patterns?
[Steve
A.] as a data point,
ADS takes 30 minutes to simulate a PRBS15
sequence.
Straw poll
2 : What forward channel data pattern should we
simulate with as a common data
pattern?
PRBS7: 0 PRBS9: 0 PRBS15: 19 No Preference: 2
Editor comment:
it was requested to include in the minutes the
primitive polynomial associated with PRBS15. This is (15, 1,
0).
The discussion resumes on
straw poll #3 : “Do we
want to use the same data pattern for crosstalk
pattern.”
[?]
are we going to specify the phase arrangements for how to link the
patterns
[Mike
A.] that would still be
open. This straw poll is only to assess whether we believe or not that
equal patterns should be used as source in all
cases.
[John
S.] we are not
considering the fact that the 64/66 scrambler will have a very long length
which will sufficiently randomize the data
sequences.
[Petri]
could we specify the pattern?
[Charles M.] also, we
should ask ourselves whether what we propose helps the simulation accuracy
and/or causes bias in the results
[Mary
M.] pathological cases are not
going to show up in simulation
[Mike
A.] certainly
not
Straw poll 3: Do we want to use the same data pattern for crosstalk pattern?
Yes: 16 No: 3 Abstained: 1
The discussion resumes on
straw poll #4 : “Should we add RJ and
DJ parameters for the Tx output?”
[Fulvio]
How would DJ be defined? Is it defined in the absence of
equalization?
[Joe
A.]
Worst case DJ and RJ need to be defined. As for DCD (duty cycle
distortion) the issue is whether people is going to simulate what is
called phase noise amplification.
[Mike
A.] maybe I
should have said RJ, DDJ and DCDJ. We shall discuss values for these
parameters at next meeting.
Straw poll
#4 : “Should we add RJ and DJ and DCD parameters for
the Tx output?”
RJ: Yes: 19 No: 1 Abstained: 2
DJ: Yes: 18 No: 2 Abstained: 2
DCD: Yes: 16 No: 3 Abstained: 3
[Mike
A.] I realize
I dropped a straw poll. There needs to be a discussion on Rx input
parameters (RJ and DJ). What I would like to is see whether we should drop
them from the spreadsheet. Is there anybody who feels they should be
kept?
[Joe
A.]
You will still need RJ and DJ but that is not what you
meant.
[Mike
A.]
Right.
By
acclamation it was agreed to drop the
Rx RJ and DJ parameters.
The discussion resumes on
straw poll #5 : “Should we require a
minimum input-referred offset?”
[Adam
H.] I do not see what
offset does for us.
[Fulvio]
agreed
[Brian]
I am the one who requested it and thought this would exacerbate marginal
situations
[Mike
A.] I also see
a problem in coming up with a number which can vary an order of magnitude
depending on assumptions
Straw poll
#5 : “Should we require a minimum input-referred
offset?”
Yes: 3 No: 9 Abstained: 8
[Mike
A.] I would
encourage the abstain votes to continue the discussion on the reflector to
better clarify their position.
The discussion resumes on
straw poll #6 : “Should we require an
input-referred environmental
noise?”
[Brian]
I do not know what to do about values but system vendors guys need to
accommodate interference which we are bound to
pick-up.
[Aniruddha K.] why
input referred?
[Mike
A.] for
consistency in simulation.
[?]
is there some intelligent way to represent
it?
…. discussion ensues …
Straw poll
#6 : “Should we require an input-referred
environmental noise?”
Yes: 9 No: 6 Abstained: 4
Next meeting will be on
December 17, 2004
Attendance
Joe | Abler |
Michael | Altmann |
Stephen | Anderson |
Kofi | Anim-Appiah |
Brian | Brunn |
Joe | Caroselli |
John | D'Ambrosia |
Xiao-Ming | Gao |
Adam | Healey |
Aniruddha | Kundu |
Cathy | Liu |
Mary | Mandich |
Richard | Mellitz |
Charles | Moore |
Tom | Palkert |
Petre | Popescu |
Brian | Seemann |
Jeffrey | Sinsky |
Fulvio | Spagna |
Dmitri | Taich |
George | Tang |
Vivek | Telang |
Schelto | van Doorn |