Hi
> On Aug 29, 2015, at 7:09 AM, Magnus Danielson <mag...@rubidium.dyndns.org> > wrote: > > Hi, > > On 08/29/2015 10:01 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: >> On 28 Aug 2015 23:05, "Oz-in-DFW" <li...@ozindfw.net> wrote: >>> >>> The uncertainly listed seems to be 7.6 mHz (milliHertz, or .0076 Hz. A >>> bit better that you mention.. >> >> No, please look again. >> >> The first line does show an uncertainty of 7.6 mHz, but that is when the >> LCR meter was set to 1 kHz. The last line shows an uncertainty of 7.6 Hz >> (1000x higher) when measuring 1 MHz, which is obviously 1000x higher in >> frequency than 1 kHz. So the original uncertainty I quoted was correct. >> The uncertainty rises proportionately with frequency. > > I agree. That's how I read it too, and it is very obvious as you look at the > table. > > The calibration is in line with Chapter 10 of the manual: > http://wiki.epfl.ch/carplat/documents/hp4284a_lcr_manual.pdf > > It might be that the 7.6 ppm number was a practical uncertainty measure found > in deeper analysis along the lines of GUM and was added to the calibration > chart afterwards. For the peak-error of 100 ppm, this provide a good margin > anyway. If it’s a +/- 100 ppm error and that’s all due to temperature, you get a linear “best guess” of 2 ppm / C. That would equate to needing to know the temperature to about 3.5 C. That’s doing pretty well in an open room. If you are guessing a temperature inside a piece of gear, that’s doing pretty well running inside a chamber. Bob > > So, it's the instrument and the way it behaves, nothing in their test-setup > which is way better than needed for this particular instrument. > > In short, don't worry about it, it's OK. > > Cheers, > Magnus > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.