On Sat, 11 Apr 2020 00:24:45 -0400, [email protected] wrote: Re: time-nuts Digest, Vol 189, Issue 18
> > Message: 4 > Date: Fri, 10 Apr 2020 13:23:22 -0400 > From: Bob kb8tq <[email protected]> > To: Taka Kamiya <[email protected]>, Discussion of precise time and > frequency measurement <[email protected]> > Subject: Re: [time-nuts] OCXO and fluctuations after EFC adjustment > Message-ID: <[email protected]> > Content-Type: text/plain; charset=us-ascii > > Hi > > EFC changes by themselves are pretty much instantaneous. If you are seeing > post tune drift, it likely is from the pot or from things like a > temperature change (or draft) when you go near the part. > > If your grounds are a bit intertwined, the change in oven current will give you > a delta voltage on the ground. That can get into the EFC. Taking care of this > is harder than it seems. The 10811 has an independent ground return for the > oven, so it at least is *possible* to do in this case. > > A good starting point is to hook up a DVM on your pot. Watch the voltage after > you do a tune adjustment. If the drift you are after is in the parts > in 10^-12 range, that may take a pretty good DVM. Note that that many DVMs inject noise back into whatever they are measuring. This could be interesting if one is measuring a frequency-control voltage. A RC low pass filter may be useful. Joe Gwinn _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
