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Re: [10GBT] Validity of comparing PSDs to determine electromagnetic emissions


The calculated value of emissions+susceptibility loss is independent of
launch voltage amplitude. Lowering the launch voltage will reduce emissions,
but it will also reduce the robustness to external noise equally, thus
keeping the total the same.


>From: "Booth, Bradley" <bradley.booth@INTEL.COM>
>Reply-To: "IEEE P802.3an" <>
>Subject: Re: [10GBT] Validity of comparing PSDs to determine
>electromagnetic emissions
>Date: Mon, 6 Sep 2004 22:58:58 -0700
>Were you assuming any power back-off mechanism for the 0m calculation or
>was this assuming the same launch power that would be used for 100m?
>-----Original Message-----
>From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On
>Behalf Of sailesh rao
>Sent: Monday, September 06, 2004 12:37 PM
>Subject: Re: [10GBT] Validity of comparing PSDs to determine
>electromagnetic emissions
>The total EMI advantage I computed for PAM8 over PAM12 (2.6dB to 3.8dB)
>over the agreed upon Models, 1, 2 and 3, which include worst-case Alien
>NEXT. i included the 0m calculation (4.5dB) as a basis that cannot be
>There are enough EMI challenges in 10GBASE-T (~6dB higher emissions than
>1000BASE-T, ~7dB lower susceptibility than 1000BASE-T, for a total of
>worse EMI performance than 1000BASE-T) for us to begin by throwing away
> >From: Hugh Barrass <hbarrass@CISCO.COM>
> >Reply-To: "IEEE P802.3an" <>
> >To:
> >Subject: Re: [10GBT] Validity of comparing PSDs to determine
> >electromagnetic emissions
> >Date: Mon, 6 Sep 2004 07:35:13 -0700
> >
> >Sailesh,
> >
> >The tests are generally conducted under "worst case" conditions. That
> >is, conditions where emissions are highest for EMC testing, or where
> >equipment is most susceptible for immunity testing.
> >
> >For current equipment there is no consideration of alien NEXT
> >environment as this is assumed to be unrelated to the emissions or
> >susceptibility of the equipment. If the alien NEXT environment of 10GBT
> >does effect the EMI performance then that will have to be taken into
> >account when the test guidelines for that type of equipment are
> >
> >As the standard develops we will have to keep this in mind.
> >
> >Hugh.
> >
> >sailesh rao wrote:
> >
> >>Hi All,
> >>
> >>Regulatory EMI tests are not conducted with worst-case alien NEXT
> >>environments set up in the range.
> >>
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