Liav:
I am concerned at the extent of the peak
to valley variations seen in the Return Loss characteristics below. I think
that a peak-to-peak vs. local average value might be a good metric.to include.
I will work up a couple of test cases to get some numbers.
ed
Dr. Edward P. Sayre, P. E.
North East Systems Asscoiates, Inc.
[T]: +1-781-837-9088
[C]: +1-978-314-4940
[E]: esayre@xxxxxxxx
From: Liav Ben Artsi
[mailto:liav@xxxxxxxxxxx]
Sent: Wednesday, October 17, 2012
12:15 PM
To:
STDS-802-3-100GCU@xxxxxxxxxxxxxxxxx
Subject: [802.3_100GCU] Return
loss waveform at TP0a and TP5a
Hi
All,
During
the
93.8.1.4 Transmitter output return loss
93.8.2.2 Receiver input return loss
94.3.12.4 Transmitter output return loss
94.3.13.2 Receiver input return loss
This
specification was intended to correlate to the package return loss as specified
for COM @TP0 and TP5. These are specified in:
Table 93–8—Channel operating margin parameters
Table 94–17—Channel operating margin parameters
A
concern was brought up that the extrapolation of the package return loss values
from the device pins to TP0a and TP5a:
1.
took into account the extra waviness of the return
loss.
But:
2.
Gave extra non relevant margin to the low frequency
return loss
I
find this concern very reasonable and therefore suggest to fix the limit at
TP0a and TP5a to take into account that the test fixture has very minimal loss
@ low frequencies.
The
way I suggest doing that is by defining the following two sections of return
loss:
RL(f)
≥ 6.25*f+10.3125 ; 0.05<f<3 ; f in GHz
I
will be referencing this E-mail in the suggestion resolution to the comment I
will be submitting.
Inputs
are welcome (let’s have the debate here and save the time in Tx J).
Best
regards,
--Liav