RE: A couple of questions on clause 52
Jonathan -
I'm not yet as familiar with the document as I'd like to be, but at first
glance, all that is required is to change the 2 table rows that are
presently labeled as OMA/2 to OMA and add +3 dB to the associated numbers.
Penalties are in dB, independent of the budget endpoints, and don't need to
change.
Average powers (in dBm) appear to be associated with "off" states and max
powers for laser safety and overload control, and so are not related to the
budget. Assuming they are correct now, they don't need to change.
As usual, I don't think you're missing anything...
Tom
Stratos
425/775-7013
-----Original Message-----
From: Jonathan Thatcher
To: 'Lindsay, Tom'; 'serialpmd '
Sent: 4/18/2001 10:50 PM
Subject: RE: A couple of questions on clause 52
Tom,
Let us assume that we do as you say (and I imply) and convert everything
to OMA (pk-pk). What other changes are required for the document? Would we
"convert" the Average Rx power (I wouldn't think so)? Would we change our
representation of the link power budgets and penalties to be in terms of OMA
(again, I wouldn't think so)?
In short, this would seem to be a bounded an fairly simple change. What
might I be missing?
jonathan
> -----Original Message-----
> From: Lindsay, Tom [mailto:TLindsay@xxxxxxxxxxxxxxxxxxxx]
> Sent: Wednesday, April 18, 2001 4:13 PM
> To: 'Jonathan Thatcher '; 'serialpmd '
> Subject: RE: A couple of questions on clause 52
>
>
> Jonathan and others-
>
> There are some that prefer OMA (pk-pk) and others that prefer
> OMA/2 (pk). I
> strongly prefer OMA for the following reasons:
> 1. OMA has already been established and is well understood in
> Fibre channel
> and HIPPI.
> 3. OMA represents the contrast between logic 0 and 1, which
> is directly what
> matters.
> 2. OMA is simpler to explain, visualize, and implement (such
> as on a scope.
> Finding toplines and baselines are easier than finding a
> waveform midpoint).
> 4. Some may think they can relate and therefore measure OMA/2
> with average
> power on a power meter. Because of the loose control on
> extinction ratio,
> the two values can be quite different. We should not
> encourage any attempts
> at such a relationship.
> 5. To your question - we must be consistent throughout the
> optical link.
> That is, use the same definitions and units at the
> transmitter as we use at
> the receiver, etc.
>
> Tom Lindsay
> Stratos
>
> -----Original Message-----
> From: Jonathan Thatcher
> To: serialpmd
> Sent: 4/16/2001 8:29 PM
> Subject: A couple of questions on clause 52
>
>
> Would someone please remind me:
>
> 1. Why is it that in the OMA tables that we spec the dBm
> range in OMA/2
> instead of just OMA? We specify the Rx in OMA (dBm). Are we
> just testing
> to see if the user knows to add 3dB when working on the link
> budgets? :-)
>
> [rest deleted...]
>
> jonathan
>