Hi David: The most straight forward way is to make a time interval measurement between the two 1 PPS signals. It's good to use a BNC-T connector at the SR620 front panel and a scope so that you can set the trigger levels at 50%. If both sources are TTL (0 to 5 volts open circuit) and you use the 50 Ohm termination in the SR620 then the pk-pk will be 2.5 volts and a trigger level of 1.25 volts works well.
By setting SAMPLE SIZE size to some number like 500 (seconds since your have 1 PPS input) you can then DISPLAY either MEAN or JITTER. The latter is a very good indication of what's going on. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com David Forbes wrote: >Folks, > >We have a rubidium oscillator in a laboratory here that is ripe for >calibration against a primary standard. We have installed a Datum 9390 >GPS receiver next to it as well as an SR620 counter. > >Can any of you recommend a good operating mode to make the SR620 reveal >the rubidium drift rate in a reasonably short time a couple days is OK) >so that we may adjust it to near zero? > >We have both 10 MHz and 1PPS available from both sources. > >We don't currently have a logging computer connected to the SR620, but >we can do that if needed. > > > >_______________________________________________ >time-nuts mailing list >[email protected] >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
