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John,
I am
concerned about both nominal manufacturability and tolerance variation. The new
limit line will make 1 m achievable only in theory: with relatively "wet" 13SI
type laminate, large trace width, and unsatisfactory (from the industry's point
of view) signal density. Any manfacturing deviation or degradation due to
environmental effects, connector wear, mishandling, etc will push things over
the limit very quickly, as you have previously demonstrated.
I
guess I am still unclear on what we need to go through all
this.
Gourgen
-----Original Message-----
From: DAmbrosia, John F [mailto:john.dambrosia@tycoelectronics.com] Sent: Wednesday, January 18, 2006 4:45 PM To: Oganessyan, Gourgen; STDS-802-3-BLADE@listserv.ieee.org Subject: RE: [BP] Interference tolerance test channels Gourgen, Please define whether you mean a physically realizable channels includes tolerances for all of the variations discussed before.
John
-----Original
Message-----
Rich,
You just did a mathematical construction, right? Is this channel physically realizable?
Gourgen
-----Original
Message----- Did it! I built a channel that has 3db less loss at 5GHz with out impacting the loss at 1GHz. Also I created the AF coefficients to match this channel. See attached zip file. I also checked the causality of the s4p as well. J …Rich From:
DAmbrosia, John F [mailto:john.dambrosia@TYCOELECTRONICS.COM]
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]
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