# [SI-LIST] Re: Questions about Compliance interconnect magnitude response and ISI loss in XAUI standard

• From: "Wei Zhou" <wzhou@xxxxxxxxxxx>
• To: "liuluping 41830" <liuluping@xxxxxxxxxx>, "Vinu Arumugham" <vinu@xxxxxxxxx>
• Date: Wed, 16 Jan 2008 20:19:02 -0800

```Luping,

When the channel is used as a vehicle to qualify silicon, a worse channel is
more desired. For the compliance testing, the point is to test the silicon, not
the channel itself. You want to use a worse channel to perform the test.

Regards,

Wei

-----Original Message-----
From: liuluping 41830 [mailto:liuluping@xxxxxxxxxx]
Sent: 2008-1-16  19:06
To: Vinu Arumugham; Wei Zhou
Cc: si-list@xxxxxxxxxxxxx; oukanghua@xxxxxxxxxx
Subject: Re: [SI-LIST] Questions about Compliance interconnect magnitude
response and ISI loss in XAUI standard

Hi Wei and Vinu:

Thank you for your kindly reply ;May be my question can be simplified as
:Why the Figure 47-6 appears that the greater loss,or  the the more
negative, than the limit line is better?

We also found a document named 'XAUI Electrical Test Suite V1.1' from
http://www.iol.unh.edu/consortiums/10gec;The setction 47.B.3 (Page 22)
talk about this problem too.It explains that the intent of this figure was to
provide a baseline value for the expected 'worst case'channel,the
limit line can be get by physically measuring the performance of a range of
real ,actual interconnects ranging in length from 46 to 56cm,and
taking the median of the observed data.Channels with greater loss are
additionally considered valid for the purpose of comformance testing.

For example:S21(Limit)=-11.4dB(Pout/Pin=10^(-11.4/10)=0.0724) at 3.125GHz, A
valid sample S21=-12.4dB(Pout/Pin=10^(-12.4/10)=0.0575) at 3.125GHz

That was what confused me :The more loss ,the  better.

Thanks and Regards,

LIU Luping

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----- Ô­ÓÊ¼þ -----
·¢¼þÈË: Vinu Arumugham <vinu@xxxxxxxxx>
ÈÕÆÚ: ÐÇÆÚËÄ, Ò»ÔÂ 17ÈÕ, 2008 ÉÏÎç1:41
Ö÷Ìâ: Re: [SI-LIST] Questions about Compliance interconnect magnitude response
and ISI loss in XAUI standard

> Luping,
>
> It may be useful to define a compliance interconnect as one that
> is used for stress testing and a compliant interconnect as one
> that would be used in a product. A compliant interconnect should
> fall above the limit line. Compliance interconnects should fall
> below the limit line. So, channels with greater loss (than the
> limit line ) are considered valid for stress testing.
>
> Thanks,
> Vinu
>
>
>
> iuluping 41830 wrote:
> > Dear  SI-listers:
> >
> >    802.3-2005_section4 Clause 47.4.1 and Figure 47-6 specify the
> characteristics for a test chanel that is refered to in the clause
> as a "Compliance Interconnect".
> > The figure gives a S21(limit) line which the transmission
> magnitude response ,|S21|,of the Compliance Interconnect in dB
> should smaller than it.
> > In general,channel specifications typically provide  a limit
> line for attenuation,which represents the maximum allowed
> attenuation value ,
> > i.e.the channel attenuation must be less than than the limit
> line .Losses are usually indicated in dB,and increase positively
> along the y-axis ,
> > However ,we see that this is not the case for Figure 47-6.We
> also see that the response for a  sample compliance interconnect
> is provided on the plot,
> > and that this response is below the limit line, however the y-
> axis is labeld in negative dB ,what does this mean?Is it means
> that the channel with
> > greater loss are considered valid ?
> >
> > Best Regards,
> > Luping Liew
> > CAD/SI Engineer
> > Network Interconnect Research Department
> > Huawei Technologies Co.,Ltd.
> > *~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~
> > Bantian,Longgang,Shenzhen 518129 P.R.C.
> > Tel:+86-755-28972154 28780808
> > Fax:+86-755-28978853
> > E-mail:liuluping@xxxxxxxxxx
> > URL:http://www.huawei.com
> > *****************************************************************
> > This e-mail and its attachments contain confidential information
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> > ail immediately and delete it!
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