Hi Don: If you want to average many (100, 1000) reads in one second you need to use the ARM function as described in appendix B of the PRS10 manual. http://www.prc68.com/I/PRS10.shtml
Have Fun, Brooke Clarke http://www.prc68.com/P/Prod.html Products I make and sell http://www.prc68.com/Alpha.shtml All my web pages listed based on html name http://www.PRC68.com http://www.precisionclock.com http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Web Cam Don @ True-Cal wrote: > Fellow Time-Nuts, > > I am having great fun with Ulrich's EZGPIB and Plotter programs to automate > my ADEV and TI measurements. Wow, what a nice set of programs, thanks Ulrich! > > I use the SR620 TIC with a Fury board as an external reference. The Fury > disciplines an 10811-60168 external oscillator. I can go unlocked to improve > the range around Tau 100s if and when necessary. For a series of tests, I > used an LPRO-101 10Mhz signal to drive B-Ch (Stop) of the SR620; the A-Ch > (Start) was set to Ref. for a Zero-Crossing TIME measurement on the TIC. I > streamlined the EZGPIB SR620 query program and experimented with counter > settings to minimize the inevitable and inherent latencies of the computer > layers, network, GPIB-Enet/100 bridge and the counter (counter being the > worst). With the counter set to 100 samples and the 1KHz "Ref" being used as > the START, I was expecting a new, 100 sample TI average, every 0.1 seconds. > My first evidence of something not being ideal was embedded in the details of > the EZGPIB output console and accompanying file. Sometimes there were 7, 8 or > 9 samples per second of time and never 10. Also, the total time span of a > large coll ection of samples was always slightly longer than the product of the sample rate and count. I used Excel to scan 18000, 0.1s TI samples to determine what the actual statistics might be: > > Average = 0.122302796 sec > Min = 0.188015099 sec > Max = 0.108984648 sec > > Since the ADEV function as well as Ulrich's Plotter program requires a > constant Tau-0, I experimented with the nominal 0.1s and the real "average" > of 0.1223s Tau-0 setting and attached a graph that illustrates the variance > across Tau. My question is; what is "acceptable" practice for defining Tau-0 > when the likelihood of having a stable sampling interval is difficult. It was > rather simple to specify a more accurate time sample interval once determined > by the extra step of spreadsheet analysis and the effect on the results is > obvious. But that is still, only an average. What about the effect of the > deviation about the average value? It would seem that would be a much more > complex issue to deal with. > > See attached export or Plotter graphic. > > Regards... > Don > > > ------------------------------------------------------------------------ > > _______________________________________________ > 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. _______________________________________________ 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.
