); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Gentlemen,
Using oscilloscopes to measure relative phase has been widely used for a long time. The setup appears in many H-P Op/Srv manuals in the adjustment procedure section to calibrate the instrument timebase to a shop standard. But, it's not a useful technique for settings more precise than 1 or 2E-10 in the best situation. The process degrades badly as the 'scope sweep speed increases past 10ns/div since a 10MHz sinewave slope is approaching a rather flat line. Watching 2 rather flat lines for precise zero crossings isn't as simple as it seems. In addition, any noise/drift or outright shifts in vertical position obscure the result & aren't unusual during a 16 minute window. Delayed sweep operation just adds more uncertainty, so you end up waiting for the phase difference to drift to the point that both traces are displayed in the same window. But now, they won't stay there for 16 minutes, unless they're already VERY close to matching. The whole process demands that you walk your way down to locking up the 2 sources. It's more painful than it sounds! Regards, Pete Rawson _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
