> Hello guys, > > some time ago we talked about curious humps in the ADEV of the SRS PRS-10 Rb > at around 20s intervalls.
Can you refresh me on the topic? I didn't see any PRS10 humps here: http://www.leapsecond.com/museum/prs10/ > Could this be the counter self-calibrating? This is too regular to be > co-incident. I've not heard that these counters do some sort of dynamic self-calibration. Nor have I seen that sort of periodicity in a 53131 or 53132 counter. You can verify this with one or two other non-PRS10 and non-Fury sources: set them in the range of something like 1e-10 apart and collect data for a couple of minutes. You should see them drift apart at the rate of 100 ps per second with expected amount of noise but no other anomalies. > > Has anyone else seen this? > > I don't see this on a scope when comparing two 1PPS's so I do think it's the > counter. This is the right approach -- to substitute another source, to substitute another counter, another cable, another DC power supply, until you locate the culprit. Just to get a clear idea of your lab set up; how is your counter configured exactly; int or ext ref? trigger levels? 1X or 10X attenuation, etc. If you can see the readings on the 53132 display, do they also happen when your PC (RS232 or GPIB?) is not electrically connected to the counter? Desktop or floating laptop? Is the Fury floating (wall wart) or are you using a grounded power supply? How is the PRS10 powered? etc. Also do the 10 MHz RF outputs show this phase jump or is it only in the 1PPS outputs? /tvb _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
