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