RE: CRPAT / CJPAT Pattern Question
Michael,
I think your second proposal makes more sense, but i think it would need to
go one step further. I think we should cycle which lane is the "different"
lane like this-
Pat 1A Pat 1B Pat 1C Pat 1D
Lane A + - - -
Lane B - + - -
Lane C - - + -
Lane D - - - +
Where the "+" lane would be the pattern, and the "-" would be the
compliment. Thus, all channels get examined. If only 1 lane is tested,
then the test is specific to the implemenation, where if all lanes in a
channel get examined, then the performance of the channel is fully examined
rather than 1/4 of it.
John
-----Original Message-----
From: Michael Debie [mailto:mdebie@xxxxxxxxxxxxx]
Sent: Wednesday, June 13, 2001 5:41 PM
To: DAmbrosia, John F
Subject: RE: CRPAT / CJPAT Pattern Question
John,
A good diagnostic for cross talk would be to place different frequency clock
like patterns on all of the lanes. This could tell us the amplitude of
cross talk per other lane and where it comes from. Also, if we run the same
patterns on three lanes and one lane different, we could see how the other
three lanes combine to effect cross talk on the lane under test.
Regards,
m
-----Original Message-----
From: DAmbrosia, John F [mailto:john.dambrosia@xxxxxxxxxxxxxxxxxxx]
Sent: Wednesday, June 13, 2001 4:21 PM
To: Serial PMD reflector (E-mail)
Subject: CRPAT / CJPAT Pattern Question
Everyone,
The 10GEA XAUI Interoperability Group met this week, and were discussing the
use of the CRPAT / CJPAT patterns for its testing. A general observation
was that the same data pattern appear on all 4 lanes synchronously, which
means crosstalk is not really being testing, which was probably being
accounted for by connector crosstalk budget of 4%. Tyco presented data
http://grouper.ieee.org/groups/802/3/ae/public/may01/dambrosia_2_0501.pdf
that showed that crosstalk, which resulted from signals switching in-phase
(i.e. high to low or low to high), could actually improve the overall
response of the system. Thus, the resultant eye is improved and would be
best case, and not even nominal (all adjacent channels quiet).
Obviously, there are a lot of system variables that come into account when
considering crosstalk, but it would seem that we could improve the harshness
of these patterns by not making all 4 channels have the same data patterns.
John D'Ambrosia
Manager, Semiconductor Relations
Tyco Electronics Corporation
Tel. 717.986.5692
Mobile 717.979.9679
email - john.dambrosia@xxxxxxxxxxxxxxxxxxx