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

• From: liuluping 41830 <liuluping@xxxxxxxxxx>
• To: Vinu Arumugham <vinu@xxxxxxxxx>, wzhou@xxxxxxxxxxx
• Date: Thu, 17 Jan 2008 11:06:10 +0800

```
Hi Wei and Vinu=3A

Thank you for your kindly reply =3BMay be my question can be simplifie=
d as =3AWhy the Figure 47-6 appears that the greater loss=2Cor  the the m=
ore
negative=2C than the limit line is better=3F

We also found a document named =27XAUI Electrical Test Suite V1=2E1=27=
from http=3A//www=2Eiol=2Eunh=2Eedu/consortiums/10gec=3BThe setction 47=2E=
B=2E3 (Page 22) =

was to provide a baseline value for the expected =27worst case=27channel=2C=
the =

limit line can be get by physically measuring the performance of a range =
of real =2Cactual interconnects ranging in length from 46 to 56cm=2Cand =

taking the median of the observed data=2EChannels with greater loss are a=
dditionally considered valid for the purpose of comformance testing=2E
=

For example=3AS21(Limit)=3D-11=2E4dB(Pout/Pin=3D10=5E(-11=2E4/10)=3D0=2E=
0724) at 3=2E125GHz=2C A valid sample S21=3D-12=2E4dB(Pout/Pin=3D10=5E(-1=
2=2E4/10)=3D0=2E0575) at 3=2E125GHz

That was what confused me =3AThe more loss =2Cthe  better=2E =

Thanks and Regards=2C

LIU Luping

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=B7=A2=BC=FE=C8=CB=3A Vinu Arumugham =3Cvinu=40cisco=2Ecom=3E
=C8=D5=C6=DA=3A =D0=C7=C6=DA=CB=C4=2C =D2=BB=D4=C2 17=C8=D5=2C 2008 =C9=CF=
=CE=E71=3A41
=D6=F7=CC=E2=3A Re=3A =5BSI-LIST=5D Questions about Compliance interconne=
ct magnitude response and ISI loss in XAUI standard

=3E Luping=2C
=3E =

=3E It may be useful to define a compliance interconnect as one that =

=3E is used for stress testing and a compliant interconnect as one =

=3E that would be used in a product=2E A compliant interconnect should =

=3E fall above the limit line=2E Compliance interconnects should fall =

=3E below the limit line=2E So=2C channels with greater loss (than the =

=3E limit line ) are considered valid for stress testing=2E
=3E =

=3E Thanks=2C
=3E Vinu
=3E =

=3E =

=3E =

=3E iuluping 41830 wrote=3A
=3E =3E Dear  SI-listers=3A
=3E =3E
=3E =3E    802=2E3-2005=5Fsection4 Clause 47=2E4=2E1 and Figure 47-6 spec=
ify the =

=3E characteristics for a test chanel that is refered to in the clause =

=3E as a =22Compliance Interconnect=22=2E
=3E =3E The figure gives a S21(limit) line which the transmission =

=3E magnitude response =2C=7CS21=7C=2Cof the Compliance Interconnect in d=
B =

=3E should smaller than it=2E
=3E =3E In general=2Cchannel specifications typically provide  a limit =

=3E line for attenuation=2Cwhich represents the maximum allowed =

=3E attenuation value =2C
=3E =3E i=2Ee=2Ethe channel attenuation must be less than than the limit =

=3E line =2ELosses are usually indicated in dB=2Cand increase positively =

=3E along the y-axis =2C
=3E =3E However =2Cwe see that this is not the case for Figure 47-6=2EWe =

=3E also see that the response for a  sample compliance interconnect =

=3E is provided on the plot=2C
=3E =3E and that this response is below the limit line=2C however the y-
=3E axis is labeld in negative dB =2Cwhat does this mean=3FIs it means =

=3E that the channel with =

=3E =3E greater loss are considered valid =3F
=3E =3E
=3E =3E Best Regards=2C
=3E =3E Luping Liew
=3E =3E Network Interconnect Research Department
=3E =3E Huawei Technologies Co=2E=2CLtd=2E
=3E =3E *=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E*=
=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E*=7E
=3E =3E Bantian=2CLonggang=2CShenzhen 518129 P=2ER=2EC=2E
=3E =3E Tel=3A+86-755-28972154 28780808
=3E =3E Fax=3A+86-755-28978853
=3E =3E E-mail=3Aliuluping=40huawei=2Ecom
=3E =3E URL=3Ahttp=3A//www=2Ehuawei=2Ecom
=3E =3E *****************************************************************=

=3E =3E This e-mail and its attachments contain confidential information =

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=

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=3E mail in error=2C please notify the sender by phone or em
=3E =3E ail immediately and delete it!
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