Mark, Nice work. As stated in your paper under Fig 20 "both packaging and signal rise time" contribute to the difference seen in the measurement. It would be interesting to see what the difference would be with the same rise time from the two device. And that answers the question whether the signal rise time or package ground ball distribution is really the deterministic factor here. (or both? 50-50 or 30-70?) Since both device have programmable edge rate, I would assume it is possible to find settings on the two device that will result in the same signal rise time. regards, Wei Hey all, >Some of you may have already attended this, but I wanted to draw your >attention to a WebCast seminar and accompanying paper that was released >yesterday. The topic is a joint study by Xilinx and SigCon (Howard >Johnson) of crosstalk and power system noise in FPGA systems. > >The paper: >http://www.xilinx.com/products/virtex4/pdfs/BGA_Crosstalk.pdf > >The archived WebCast (might not be available until tomorrow): >http://www.xilinx.com/events/webcasts/tol/01feb05.htm#3 > >The WebCast is a full hour with Q&A at the end; the paper /seems /long >but is actually pretty easy to read. I especially like Howard's >explanation of the crosstalk model of power system noise and why it's >appropriate to the large BGA scenario. > >I'd be very interested to hear feedback from people on the list -- >factors we didn't consider, overall usefulness of the information >presented, ideas for future studies on the same measurement platform. > >Thanks! >mark ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu