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Norm - these are immediate issues that came from today's call. We can
discuss these when you call.
- EQ length
- Are we willing to provide finite EQ code for a comment?
- Quantify effects of non-linear shifts with practical waveforms vs. EQ
length (100,50 vs. 14,5) - I have not digested the latest work.
- Can we demonstrate pre-emphasis to reduce TWDPx,y and IPx,y with
pre-cursor fibers?
- Electrical reflections are ~100 bits per meter round trip, ~2 bits per 2
cm.
- Can probably be ignored for TP2.
- However, TP3 setups will probably have these problems and should be
tested with a realistic EQ length. I'd rather have only one
"code".
- un-normalized SNR signal quality metric
- Scatter plots show almost no correlation between normalized penalty and
equalizability or "cliffs", so there is no shown need for
normalization
- Need to demonstrate SNR vs. TP2 signal strength across range of
waveforms
- How to account for TP2-dependent noises? It causes significant change to
the -13 dBm value (see attached).
- Demonstrate difficulty and sensitivity of OMA measurement or
extraction
Tom
----- Original Message -----
Sent: Tuesday, July 12, 2005 8:13
AM
Subject: [10GMMF] Updates to reminder for
TP2 call 7/12/05
See updated proposed agenda below.
Tom
----- Original Message -----
Sent: Monday, July 11, 2005 8:50
PM
Subject: [10GMMF] Reminder for TP2 call
7/12/05
- Date: Tuesday, 12 July, 2005
- Time: 9:00 AM Pacific
- Duration: 1:30 max
- Number: 401-694-1515
- Access code: 421721#
Agenda
- Attendance
- Review previous minutes (thanks, Mike)
- Build agenda
- Technical discussions
- Vivek presentation - Correlation of
measured waveform penalties with equalizer lengths
- ClariPhy
- Presentation - Penalty sensitivities due
to Rx impairments vs. TP2 waveforms
- Presentation - Updates on measured waveform
linearization results
- Discussion - Automated OMA measurement in TWDP
code
- Finisar - TWDP on TP3 setups?
- Conclusions before meeting?
- Next call
- Propose meeting again 7/14 (Thursday). We need
to attempt to draw conclusions before the July meeting, but I've just
returned from vacation and have not been able to digest all the new
data, and others may need a couple of days to digest today's
presentations.
Tom Lindsay ClariPhy Communications tom.lindsay@clariphy.comphone:
(425) 608-0209 or (949) 480-9210 cell: (206) 790-3240 fax: (425)
608-0232
----- Original Message -----
Sent: Thursday, July 07, 2005 2:43
PM
Subject: [10GMMF] Minutes for TP2
call 7/5/05
Attendance (no
order)
- Lew Aronson
- David Cunningham
- Ernie Bergmann
- Piers Dawe
- Mike Dudek
- Majid Barazande-Pour
- Norm
Swenson
Agenda
- Attendance (done, see above)
- Build agenda (done)
- Technical discussions (see below)
- Next call (see below)
Mike Dudek
moderated the call in Tom Lindsay's absence.
Discussion (TWDP)
- Further
discussion took place on the comparison metrics of SNR, TWDP, and
implementation penalty (IP) with finite length EQ that Tom had
presented last week. See http://grouper.ieee.org/groups/802/3/aq/public/upload/AnalysisofSNR_TWDPandfinitelengthIPvs.measuredwaveforms.pdf.
- Norm Swenson
described work that he had performed to attempt to evaluate whether
the TWDP degradations seen for practical waveforms was related to
non-linearities or other factors. Early results showed that the
TWDP was reduced by 0.2 to 0.5dB for best linear fits to a selection
of the waveforms from Tom's presentation. He sent a graph of
these early results to the reflector (based on Ewen 4.6dB pre-cursor
stressor). He intends to present more results next
week.
- Concern
was again expressed that Tom's presentation
showed that when normalized to OMSD only
parts with significant pre-emphasis had lower TWDP than the supposedly
worst case 47ps Gaussian pulse, and that we need to make sure that
"reasonable practical" Tx's will pass the test. ie we may need
to allocate some of the implementation penalty to the Tx if we use
this normalization method.
- Lew Aronson suggested that practical
TP3 stressed eye testers may overstress the Rx and said that he was
going to be performing TWDP like tests on his tester.
- David Cunningham stated that he had
measured Pie-D on some commercially available BERTS and found that
they had 0.2 - 0.5dB penalty not all of which was related to rise/fall
times. This indicates that making a perfect TP3 stressor
will not be easy.
- Mike Dudek suggested that we will
have to determine what to do when the waveforms have been matched
as well as possible to the pulse shapes in the standard and the TWDP
like test of the resulting waveform does not match the
expected TWDP like result. He suggested that there are 3 choices
with the noted advantages/disadvantages.
- 1 Just state
that test implementers need to minimize the difference and that the
difference will result in conservative results. (similar to
what is said about noise in the 10G 802.3ae standard for the
stressed receiver sensitivity testing). Not recommended
based on experience with the 10G stressed eye testers.
- 2 Say that any
difference in TWDP should be used as a correction factor for the
stressed sensitivity. This is still probably
conservative as it is likely to result in more distortion to
equalize but with somewhat higher input power. It is however
relatively easy to incorporate into the standard.
- 3 Say that the
waveshapes should be adjusted to create the required TWDP.
Probably the fairest test for the receivers, but may be difficult to
state in the standard how to do this.
- It was also suggested that it would
be useful to have a name for the "TWDP like test" (ie test of TP3
signal with TWDP like code without the simulated fibers) to more
easily differentiate this test.
Next week
- Tom will be back
- Vivek planning to present on
correlation across EQ lengths (action from 6/23). (Hopefully this will take place. Vivek
was not on the call to confirm).
- Norm Swenson
planning to present more information on his analysis of the TWDP
results from the various eyes.
- Lew Aronson
planning to present information on TWDP like measurements on a TP3
stressed tester with comparison to theory.
- Requests for new sims
- ~0/30/60 psec Gaussian with pre/post,
long/short EQs, normalized with OMSD/OMA. Show SNR, TWDP, and
IP. (Carried forward from 6/28
call)
- Other IP mechanisms.
- Reminder this
will be the last day for comments to rev 2.1
Next call
- Date: Tuesday, 12 July, 2005
- Time: 9:00 AM Pacific
- Duration: 1:30 max
- Number: 401-694-1515
- Access code: 421721#
Thanks,
Mike Dudek
Director Transceiver
Engineering
Picolight Inc
4663 Nautilus Court South
Boulder
CO 80301
Tel 303 530 3189
X7533.
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