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@tycoelectronics.com