RE: From serial PMD call, 15 May
So does this suggest that mask testing should not use a filter?
I don't think so. One could still use a filter to pass the mask (to
suppress overshoot and other distortions). If it still clears the
corners with the filter, then obviously it would clear the corners
without the filter.
Can I assume that a filter was not used in your analysis where you let
the mask set the risetime spec?
Tom
-----Original Message-----
From: DAWE,PIERS (A-England,ex1) [mailto:piers_dawe@xxxxxxxxxxx]
Sent: Friday, May 18, 2001 3:13 AM
To: Lindsay, Tom
Cc: 802.3ae Serial
Subject: RE: From serial PMD call, 15 May
Tom,
At present the draft standard, and the link model, start with the
unfiltered
rise time. The link model converts this into 10-90% rise time in box
P4,
"Ts(10-90)", which is used (box F14 and column F) to create filtered
10-90%
rise times in box G14, ("Tc" at 2 m) and column G. These are used to
calculate ISI and other penalties.
I hope that this addresses your question,
Piers
> -----Original Message-----
> From: Lindsay, Tom [mailto:tlindsay@xxxxxxxxxxxxxxxxxxxx]
> Sent: 17 May 2001 23:50
> To: DAWE,PIERS (A-England,ex1); 802.3ae Serial
> Subject: RE: From serial PMD call, 15 May
>
>
> Piers - In FC, the present ristime spec is without a filter, however a
> filter may be used (not required) to pass the mask test.
>
> The concern is about risetime being too slow (the low jitter case); I
> don't think anyone is worried about it being too fast. It may not have
> large effect, but testing against a mask with a filter will
> require the
> source to have a faster risetime than if measured without a filter.
> Which scenario are you considering? Which case (of both) have been
> considered in the link model?
>
> Thanks,
> Tom Lindsay
> Stratos Lightwave
> 425/672-8005
>
>
> -----Original Message-----
> From: DAWE,PIERS (A-England,ex1) [mailto:piers_dawe@xxxxxxxxxxx]
> Sent: Thursday, May 17, 2001 10:29 AM
> To: '802.3ae Serial'
> Subject: From serial PMD call, 15 May
>
>
>
> Discussion of proposed deletion of risetime spec. line for 1310 serial
> ----------------------------------------------------------------------
> We inherited this from Fibre Channel. SONET don't have it. Fibre
> Channel
> have discussed removing it, without strong views either way.
> Piers with
> help from Petar and support from others will present how we can live
> without
> it.
>
> Chromatic dispersion penalty
> ----------------------------
> Our modelled number is unrealistic for two reasons:
> Spectral width is likely much less than the 0.4 nm model number
> Dispersion penalty is worked out for an incoherent source and
> ours
> is coherent. In Petar's terms, we are using a power model
> and we should
> be
> using a field model.
> Luckily these two effects would move the error in opposite directions
> and we
> are discussing a penalty of only ~0.5 dB. This is thought to be
> pessimistic.
>
> Comments on Draft 3.0
> ---------------------
> We had more reviewers than last time which is good. Clause 52 has
> collected
> about 200 comments including 34 TRs.
>
> Next meeting
> ------------
> There will be no meeting on 22 May. Will likely restart at the usual
> time
> on 29 May:
> 15:15 GMT = 4:15 pm BST = 17:15 CET = 11:15 am EDT = 8:15 am
> PDT,
> Tuesday (today)
> +1(816)650-0631 Access code 39209
> Piers
>