Oracle poses two questions
Istvan Novak, a distinguished engineer helping build big iron servers at Oracle, brings at least two specific questions to DesignCon this year.
When using a time-domain reflectometer to measure impedance on today’s high-density boards the system “appears to be artificially out of spec for a number of cases,” Novak said. “This year there are significant limitations because we are pushing longer traces with higher density boards, so there’s more resistance,” he explained.
It’s no small issue, given impedance is the main metric for validating an electrical spec. “So what I am looking for is feedback from OEMs, pcb makers, maybe even some academics on solutions for this problem,” he said.
Novak also has been dogged by problems using the miniature differential probes on vector network analyzers to test an interconnect. “There are open exposed metal pieces of the contact which will have coupling between them, and currently none of the commercial calibration processes take out those interactions so we end up doing a measurement with a kind of systematic error--how do we correct for that?” he asked.
As a veteran member of the DesignCon tech advisory board, he has already had a chance to review several papers similar to those from Ritchey, Healey and Telian.
“Over the years this event has become for us the compass showing the direction to go,” he said. “If you just go and listen to what people talk about, you get a pretty good cross section of what the industry needs to address,” he said.
[Click here to register for DesignCon 2013, Jan. 28-31 at the Santa Clara Convention Center. Options range from an All-Access Pass to Free Expo Admission, which includes the option to attend a dozen tech training sessions.].
Track on test and measurement methods
Keynote by National Instruments’ business and technology fellow