On Tue, 03 Jul 2012 19:08:56 +0200, Azelio Boriani wrote: > Yes, you can ask here about these things. Anyway, the best is to use the > TBolt as a reference (not necessarily on the external ref of the > counter) and test another oscillator or GPSDO. For example: feed the > TBolt PPS to A, the GPSDO_under_test PPS to B and measure the stability > of the time interval using TIME A-B. Ideally it should be a constant > value (even if not exactly 0, but constant). The phase data (the time > interval errors) can be collected and an Allan deviation computed.
Azelio , first ... Thanx for walking me through this. I'll try the above later on. But what you're saying is that when used as a TIC A->B , i don't need the TBolt on ext-ref ? , or do i need the TBolt on both Ext-Ref & on Chan-A ? If i don't use the TBolt on Ext-Ref , won't i get hit by having a Std-Osc installed ? I have a GPS Antenna-Splitter , another TBolt (just need to assemble the PSU) , and also a X72 Rubi & a few FEI-5680's. So i could try those when i'm a bit more familiar with the Counter & program. > >The default sampling time is 200mS > Ahhh ... Thanx now i know why my 1hr Trace Duration was so fast. I assumed that Timelab would set the sampling interval written in Timelab via GPIB. But i'll just select 1sec manually. > So, to try your setup (TBolt on EXT REF and A): first inform the TimeLab > that you have 1 second frequency samples, then set the sampling time to > 1 second (use FUNCTION button on the PM6680) and retry collecting > data.In this case the predicted uncertainty is 0.005 (5E-10) and sholud > average out to 5E-13 in 1000 seconds taking into consideratin that the > full 12 digit resolution is available at the PM6680 GPIB (that is, the > GPIB has more digits than the display can show, see page 11-18 of the > manual). > I will try this now , and i assume i should then select Frequency in the Data Type - In TimeLab , as i don't use A->B measurements .. Or ? I'll also dig into - How to calculate measurement errors , as you describe above. Regards CFO - Tnut-Beginner _______________________________________________ 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.
