Re: [BP] Question regarding Channels
John,
Is your channel data available for download from the 802.3sp web site?
Howard
DAmbrosia, John F wrote:
> 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
>