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Charles Given the number of changes we are
proposing without too much data analysis, it would be strongly recommended that
we have this meeting. From: Charles Moore
[mailto:charles.moore@AVAGOTECH.COM] guys, … Rich From: DAmbrosia, John
F [mailto:john.dambrosia@TYCOELECTRONICS.COM]
Goergen, You really can’t do that if you are
trying to move forward robbing from both sides of the problem to come up with
the overall solution. John -----Original Message----- John, We decided at the first
pass to decouple crosstalk from attenuation and just look at attenuation. No
doubth taking crosstalk into account will make things much worse (with any
industry acceptable signal density). We could get it to work if if we made the
signals sparse, but that's no good as fas as anyone is realistically concerned. Gourgen -----Original Message----- Steve, But also realize that the
general line also has built in margin for it to account for temperature,
environmental, and material variation as well. The line as
currently proposed has to be examined to look at from several aspects.
For example, the Molex channels are hugging the new proposed 23 dB line.
5” are on the daughtercard and 35” are on the backplane, which uses
a typical 7 mil line. So we are saying that to meet the skin effect at
the lower frequencies we need a 7 mil wide line? I think that is too
far. Look at the attached figure – 7 mil wide traces hug that
line. I think we have moved it too far upward. I don’t see any
efforts yet on reducing the problem via the crosstalk aspect of the
problem. Has that been abandoned? I don’t think all of the
burden at this time should be shifted to the channel, but should also be shared
with the total allowable crosstalk. Many of the channels did have
margin. We should look to striking a balance between the two. John -----Original Message-----
John, all:
But does a line made with the squared and cubed terms create a physically
realizable channel?
In the real channel I think there may be only two variables to play with:
skin effect and dielectric absorption.
If we base simulations on something other than this, then I think bad things
can happen like non-causal
effects.
Steve A. From:
DAmbrosia, John F [mailto:john.dambrosia@tycoelectronics.com]
Guys, Goergen
asked the magic question. Is it possible? Yes it is. We have
a squared and cubed term to play with. I am hoping Joel has some
suggestions as well. I just had a chance to do a quick scan and saw this.
I will be working on this stuff tonight John -----Original Message----- Rich, I see
now what you refer too. I am not sure how you physically relaize a channel you
are suggesting, keep low freq the same and come up at 5 GHz? Any physical
channel should result in a tilted line? Gourgen -----Original Message----- The line didn’t only tilt. It also shifted. John D looked
at a few channels as I attached. If we shift, it’s got an impact for KX
and KX4. …Rich From: Joe M
Abler [mailto:abler@US.IBM.COM]
-- |--------------------------------------------------------------------|| Charles Moore | Avago Technologies| SPG| charles.moore@avagotech.com| (970) 288-4561|--------------------------------------------------------------------| |