FreeLists / si-list / [SI-LIST] Re: near and far end crosstalk in frequency domain

[Zhangkun <zhang_kun@xxxxxxxxxx>]

Dear Istvan

I am analyzing crosstalk at low frequency. The length of transmission line is 
much less than the wave length.

From the tele-formular, it could be gotten that the polarity of electrical 
coupling and magnetic coupling are same at the near end and are adverse at the 
far end. Therefore, I think the farend crosstalk is less than near end 
crosstalk in frequency domain. This is verified by simulation in HSPICE, 
ANSOFT. I do not consider that in time domain, which has been considered in a 
lot of books.

By the way, this is still the topic about crosstalk between differential pairs 
without reference plane. I have gotten good result about near end crosstalk. 
But there is still some problem about the far end. I am sure my measurement is 
right : )

Best Regads

Zhangkun
2004.6.8
----- Original Message ----- 
From: "Istvan NOVAK" <istvan.novak@xxxxxxxxxxxxxxxx>
To: <zhang_kun@xxxxxxxxxx>; "si-list" <si-list@xxxxxxxxxxxxx>
Sent: Tuesday, June 08, 2004 8:11 PM
Subject: Re: [SI-LIST] near and far end crosstalk in frequency domain


> Dear Zhangkun,
> 
> Unless you have a perfectly homogeious cross section of
> material that carries the field, there is always a far-end
> crosstalk component, even if you have perfect termination.
> One major difference between near-end and far-end
> crosstalk is that far-end crosstalk saturates at full coupling.
> This means that beyond a certain frequency, the far-end
> crosstalk response may be bigger than the near-end crosstalk
> response.  'May be' refers to the fact that both near-end and
> far-end crosstalk vary sinusoidally with frequency, but with
> different periodicity: near-end crosstalk's periodicity depends
> on the electrical length of coupled section, far-end crosstalk's
> periodicity depends on the electrical length of coupled section
> AND the strength of coupling.
> 
> Regards,
> 
> Istvan
> 
> 
> ----- Original Message -----
> From: "Zhangkun" <zhang_kun@xxxxxxxxxx>
> To: "si-list" <si-list@xxxxxxxxxxxxx>
> Sent: Monday, June 07, 2004 11:02 PM
> Subject: [SI-LIST] near and far end crosstalk in frequency domain
> 
> 
> > Dear all
> > Now, we are analyzing the crosstalk between transmission line. There is
> something interesting. The far end crosstalk is larger than the near end
> crosstalk in frequency domain. Have anybody meet the similar problem?
> >
> > Best Regards
> >
> > Zhangkun
> > 2004.6.8
> >
> >
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