[SI-LIST] Re: Far-end crosstalk over long PCB trace
- From: Zhangkun <zhang_kun@xxxxxxxxxx>
- To: sogo.hsu@xxxxxxxxxxx, si-list@xxxxxxxxxxxxx
- Date: Tue, 07 Jun 2005 12:57:42 +0800
Dear Sogo
In my simulation about SSN, I really see the saturation. Have you set the lossy
dielectric?
Best Regards
Zhangkun
2005.6.7
----- Original Message -----
From: "Sogo Hsu" <sogo.hsu@xxxxxxxxxxx>
To: <si-list@xxxxxxxxxxxxx>
Sent: Tuesday, June 07, 2005 12:01 PM
Subject: [SI-LIST] Re: Far-end crosstalk over long PCB trace
> Dear Istvan and Craig,
>
> Thank you for your response. However, Far-end crosstalk is indeed
> getting saturation. You can easily find lots of related information
> by Googling "crosstalk saturation". Dr. Zhen Mu has several papers
> addressed on this topic. Elie Michael Issa also mentioned the
> saturation length condition. Typically, the far-end crosstalk is
> assumed to be proportional to coupled length. However, the
> estimation of linear far-end crosstalk is correct only if the system
> is weakly coupled transmission. From conservation point of view, it
> is not reasonable that the coupled energy is increased without
> limitation. Meanwhile, the saturation phenomenon can be explained by
> Modal Velocity. The mechanism of "crosstalk" is the result of
> velocity discrepancy of different modes.
>
> BRs,
>
> Sogo Hsu, Ph. D.
> Foxconn
>
> --- In si-list@xxxxxxxxxxxxxxx, Istvan Novak <istvan.novak@xxxx>
> wrote:
> > Near-end crosstalk saturates at a length matching the
> > quarter wavelength in the coupled section. Far-end
> > crosstalk, however, does not saturate any 'fixed' length;
> > the saturation depends also on the coupling. The weaker
> > the coupling, the longer coupled length you need for saturation.
> >
> > Regards,
> >
> > Istvan Novak
> > SUN Microsystems
> >
> > Sogo Hsu wrote:
> >
> > >Hi, SI Gurus,
> > >
> > >It seems a old question in SI-list. Right now, we evaluated the
> > >crosstalk noise cased by neighboring aggressors. As we know, the
> far-
> > >end crosstalk noise is proportional to coupled length and will be
> > >saturation if the coupled etching length is greater than
> constraint
> > >length. The phenomenon can be easily explained by the discrepancy
> of
> > >modal velocity in coupled-transmission line. However, we found
> the far-
> > >end crosstalk simulated by Hspice, PCB SI and SPEED XP etc.,
> will not
> > >behave the saturation even the coupled length is 100in. In my
> opinion,
> > >it is not reasonable. Pls help me to verify the solver. Thank you
> in
> > >advance.
> > >
> > >* I briefly describe the scenarios as below
> > >3-line coupled transmission line
> > >Tr=1ns
> > >
> > >Best Regards,
> > >Sogo Hsu
> > >
> > >
> > >
>
>
>
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