Electronics > Beginners
Measuring an OCXO - or not
metrologist:
My ADEV chart always seemed suspicious to me. I checked the calculations and the running sum of diff squared dropped the $ signs, so was not actually creating a running tally. I corrected this and the plot seems more like what feels right.
jpb:
--- Quote from: metrologist on October 25, 2018, 02:37:00 pm ---My ADEV chart always seemed suspicious to me. I checked the calculations and the running sum of diff squared dropped the $ signs, so was not actually creating a running tally. I corrected this and the plot seems more like what feels right.
--- End quote ---
If you want to check your plots, I'd recommend Bill Riley's program Stable 32 which is now free (it used to be quite expensive):
http://www.wriley.com/
EDIT : I see I've already mentioned this in a previous post but in a slightly different context.
metrologist:
Thanks, again. :) I did import the frequency measurements into TimeLab, but I'm not sure if I am setting the correct parameters of if this kind of measurement is valid for the data. The results are much different. Also, in TL I imported straight linear data, as if the OCXO would drive exactly 5mHz/day, and I get a straight line with upward slope where in my Excel chart I get a horizontal line.
metrologist:
And I try Stable32 using a two column text file time(s) <-> Frequency
KE5FX:
--- Quote from: metrologist on October 25, 2018, 07:13:05 pm ---Thanks, again. :) I did import the frequency measurements into TimeLab, but I'm not sure if I am setting the correct parameters of if this kind of measurement is valid for the data. The results are much different. Also, in TL I imported straight linear data, as if the OCXO would drive exactly 5mHz/day, and I get a straight line with upward slope where in my Excel chart I get a horizontal line.
--- End quote ---
Unless you are taking one sample per day, your sample interval is a bit long. :) Can you post your data set as an attachment?
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