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
1:46 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] Question
regarding Channels
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