TP3 folks - the last slide of Lew's proposals, discussed on the
TP3 call last week, involved rise/fall times. Here's my understanding of this
topic and something to discuss 10/26.
- If I understand correctly, the purpose of Petre's work is to develop
multi-tap filters to emulate subsets (currently 3: pre-,post-,~symmetrical) of
the Cambridge fiber set. It's purpose to date has not been to define
complete and final TP3 test signals.
- To match the channel emulator to the Cambridge fiber set, faster rise/fall
times are more accurate, but some slowing is appropriate to filter the 18 mode
groups down into something more practical such as 5 taps. The filtering also
helps average the wide sets of pre, post, and centered-cursor
channels from the Cambridge models down to 3 emulator setups. My gut
(not scientific) says that 30 psec is reasonable for this work. Note, all of
this matching work is analytical and does not require an actual E/O source.
- The actual TP3 test signal will be the convolution of these channel
emulators and other test equipment including the pattern generator,
the E/O source, and any additional wave-shaping or filtering that we
define. This TP3 test signal should represent the appropriate worst case
combination of the fibers and real TP2 sources we expect to find/allow in
application, and it should line up with the TP2 and dispersion penalty value
in the budget (see slide 11 in http://grouper.ieee.org/groups/802/3/aq/public/upload/TP2-TP3-budgetandimplications19Oct.pdf).
- I thought the (min value of) 47 psec applied only to the optical "source"
of the TP3 test signal - that is, everything but the channel
emulators. I'm assuming this source will be essentially Gaussian and
correctable. Since this source is trying to represent real transmitters,
including non-correctable impairments, I believe it should be some amount
greater than 47. The actual value is TBD from TP2 work.
- Petre's method uses a MMSE approach integrated over the pulse shape for
calibrating the channel emulators to the desired shapes. We may also be able
to use such a method to adjust the source rise/fall times once combined with
----- Original Message -----
Sent: Monday, October 18, 2004 9:19
Subject: [10GMMF] TP3 meeting Agenda Oct
Here is the agenda for tomorrows
Tuesday October 19th at 9am SJ, 5pm UK, 6pm Germany
in (650) 599-0374, Meeting ID:
2. Review meeting
notes from last week
Lew's additional motions (which were not heard at Ottawa). These were
forwarded by Lew last week.
TP2/TP3 link budget work. Tom Lindsay's Feedback from TP2 call
items of focus (for subsequent
i) Static channel
- channel types and exact
o i.e. do we pick pre, post cursor and quasi symmetric and if so where from?
108 fiber model?
ii) OMA measurement