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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]
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