Re: [BP] ATCA Test Channels / FEXT
john,
Does this mean that you are planning on recommending a change to
the ICR spec?
charles
DAmbrosia, John F wrote:
> All,
>
> Rich Mellitz and I were reviewing the channels being discussed, and were
> reviewing the crosstalk aggressors. We discovered a potential issue
> with the FEXT data submitted for the ATCA channels. In Tyco’s data it
> is assumed that the two FEXT aggressors are equivalent, while in the
> Intel data the FEXT data was generated where all aggressors came from
> the same line card. For a real ATCA system the two above scenarios are
> incorrect. In the ATCA system channels are based on the 8 differential
> pair from a single line card to the fabric. Thus, if you look at the
> fabric a single Rx pair would be hit on one side from an aggressor
> originating from the same line card and another aggressor originating
> from a different line card. From initial simulations Rich has done, the
> value of FEXT in a net where a single connector is shared is
> significantly lower than a case where two connectors are shared.
> Therefore, one of the FEXT aggressors is probably less than what was
> originally anticipated. Tyco is currently modifying line cards to
> provide test data that shows this effect. Hence, we should gain some
> further margin for ATCA applications by reducing one of the 3
> contributors.
>
> Cheers!
>
> John D'Ambrosia
>
>
--
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| Charles Moore
| Avago Technologies
| ISD
| charles.moore@avagotech.com
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