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