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----- Original Message ----- From: "Brooke Clarke" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Wednesday, October 24, 2007 11:05 AM Subject: [time-nuts] Scopes and 1 PPS signals? > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] RETRY > > Hi: > > While trying to figure out the O-1814 Rb source I found a 1 PPS > signal that's > less than 10 us wide. But using an HP 54501A DSO it's almost > impossible to > determine the period. http://www.prc68.com/I/O1814.shtml > > If the display is 1,000 dots wide: > at 2 us/sq the trace takes up about 4.5 squares or 450 dots, > at 200 us/sq the trace takes up about 0.045 squares or 4 dots but > the second > pulse is way off screen. At slower sweep speeds you can't see the > pulse. > > Are there scopes that allow the period of a narrow pulse to be > measured that > don't cost an arm and leg? > If your DSO has external triggering capability then using an external digital delay unit will do the trick. Something as simple as a one shot driven from the preceding pulse to do the triggering? This sort of thing is one of the reasons some analog scopes are still useful. A tek 7K mainframe with a 7D11 delay unit is a good solution. That has up to 1 second precise low jitter delay available. DaveB, NZ _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.