In past designs I just included an EEPROM so in the event of a cold start, the last settings would be known.
On Thu, 6 Dec 2012 10:45:48 -0800 (PST), "M. Simon" <msimon6...@yahoo.com> wrote: >I would use a digital pot for coarse setting. Or a manual trimpot. That way >your control signal "holds" even if your comparison goes away or if for some >reason your loop comes out of lock. Something like that also reduces the noise >contribution of the DAC. > >Simon > >============= > >Date: Thu, 6 Dec 2012 01:17:52 -0800 >From: Chris Albertson <albertson.ch...@gmail.com> >To: Discussion of precise time and frequency measurement > <time-nuts@febo.com> >Subject: Re: [time-nuts] GPSDO Alternatives >Message-ID: > <cabbxvhs_xibax15h27c38l4gevmmgnzwo+9fw2j-bqg9k5z...@mail.gmail.com> >Content-Type: text/plain; charset=ISO-8859-1 > >Don't need anything so complex. A GPSDO depend on an OCXO that is VERY >stable. It can be controlled with a very low bandwidth analog signal. > >The output from a OCXO is divided down and then the phase of the divided >down 10MHz RF is compared to the PPS and you don't need to even know the >how far apart they are. All you need to know is "led or lag" just a one >bit answer. An XOR gate or a flip flop can tell you that. > >If you want to get more fancy you can connect a few temperature sensors to >the Arduino's ADC lines and push those over the USB port along with other >statistics. Youcan also do things like control the time constants the >software uses via USB also. But you don't need this. It can be added >later or not. _______________________________________________ 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.
