All,
The
reflector appears to be very quiet. I would really like to have this
discussion so we can try to move forward.
John
-----Original
Message-----
From: owner-stds-802-3-blade@listserv.ieee.org
[mailto:owner-stds-802-3-blade@listserv.ieee.org]
On Behalf Of DAmbrosia,
John F
Sent: Tuesday,
October 05, 2004 10:39 AM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: [BP]
Question regarding Channels
All,
Since time did not allow
the conversation last week, I would like to talk
further on the reflector to understand the opposition to the
different channels that were
proposed.
I will point to my test
cases as a starting point, but the conversation really applies to all
of the channels.
As I see it, we have the
following types of impairments
in the total system-
1. Loss dominated
2. Significant stub effects
that cause deep nulls
3. Ripple in the channel
4. NEXT
5. FEXT
6. Return Loss
I believe most of the
opposition arose from 1, 2, 3 and 6, but would like
to have this conversation now.
The comments that
I heard regarding my
channels were the following -
·
The data is not freely
available. - This is no longer true, as I
indicated last week.
·
The data violates the
informative channel model. I believe there were
different cases where this happened.
o
Case 1 had minor ripple
below the mask.
o
Cases 2 and 3 were margin
cases that the Signaling Ad Hoc had requested.
o
Case 6 came from a 22"
link with top layer backplane connections. This channel was justified
for its potential appearance in systems where all cost was being
minimized, so
counterboring was not assumed.
o
Case 7 had a resonance
ripple at approximately -55dB at 11
GHz. Once again this was a
test case asked for by the Signal Ad Hoc to examine channel ripple.
Otherwise up to 11 Ghz it
is 5 to 15 dB above the informative
mask
·
Return loss is too high.
In my opinion, this is a
contradictory statement. The mask that I proposed
that fit my data was not as aggressive as Joel's
channels (#1,2,3,6,7,8,14,17,18).
All of these models
violated the proposed
SDD11 mask in the lower
frequency region, which
I proposed.
·
The data hadn't been
seen. This is a partially true statement. Tyco has been diligent in
presenting the data as quickly as gathered and processed. The SDD21
channel data for Cases 2, 4,5,6, and 7 was posted
to the Signaling Ad Hoc
reflector for the Sept 9
meeting.
So I reviewed Joel's data
that was proposed
Case #1 - 4_3_4 (4000-13)
Total 11"
Case #2 - 7_3_7 (4000-13) Total 17"
has xtalk
Case #3 - 10_3_10 (4000-13) Total
23"
Case #6 - 4_10_4 (4000-13) Total 18"
Case #7 - 7_10_7 (4000-13) Total
24" has xtalk
Case #8 - 10_10_10 (4000-13) Total
30"
Case #14 - 3_3_15_7 (4000-13) Total
29"
Case #17 - 7_20_7 (4000-13) Total
34" has xtalk
Case #18 - 10_20_10 (4000-13) Total
40"
All of these test
channels are well above the channel model. We will still need a test
case that falls very closely
on the informative
channel model, which is
where the Tyco channels 1 - 3 are falling (with
included margin cases). From both IBM and LSI's
analysis these channels were
solvable. The StatEye analysis
results were much more pessimistic (which is
an on-going problem with StatEye
that is being investigated)
than the analysis of
these companies and the crosstalk was not
applied properly.
So to me it looks
like overall loss isn't
necessarily the big problem. Loss can be very advantageous, as was
demonstrated at last week's meetings, as to how it can actually help
reduce xtalk and return loss. Ripple and nulls on the other hand
appear to be the bigger problem.
So I would like to open up
discussion as to which Tyco channels people were most concerned about.
Also, I do not know what to propose for a "weighting" scheme, so
any suggestions on this would be of extreme use in helping us to reach
consensus and move forward.
Cheers!
John D'Ambrosia
Manager, Semiconductor
Relations
Global CC&CE
Tel 717.986.5692
Fax 717.592.2470
Cell 717.979.9679