From: "Tom Van Baak" <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Datum FTS 4065B Plot Date: Wed, 14 May 2008 14:49:46 -0700 Message-ID: <[EMAIL PROTECTED]>
> > If you look at the plot I attached as a .pdf you can see that the current > > slope > > looks like a nice straight line covering almost 4 days so temperature is > > not a > > factor. The only factor I can think of is magnetic field. I guess the > > next > > step is to rotate the box 90 degrees and see what happens unless there's > > some > > other suggestions. > > Since you are plotting phase (not frequency) the nice straight > line you see simply means you have a frequency offset. This > is normal and expected with any standard compared to GPS. > > What may be temperature effects are the little wiggles above and > below the line. You can almost see they form a diurnal pattern. > > If you subtract the frequency offset before you plot, you'll get > phase residuals, which will reveal patterns in greater detail. > There are Excel functions that will help you fit lines to the data > and remove trends, etc. Email me your XLS file offline and I'll > show you. A little software tip would be to try out the fityk software. I use it for various purposes, and can fit curves for a number of functions while also allowing for some simpler form of dataprocessing. Cheers, Magnus _______________________________________________ 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.
