[time-nuts] Rb vs.Crystal OCXO
paulswedb at gmail.com
Fri Apr 25 18:02:12 EDT 2014
Welcome to time-nuts. I have to agree with Tom for an out of the box
However as so many time-nuts experiment with GPS control of these
oscillators you really can get great stability with both today and I
believe even better in the future. I like the low power of the xtal
oscillator. Thats handy when running on emergency battery here in New
England. My RB will run 2 days before the batteries shut down. But a OCXO
would most likely increase that another day or more. Plus run the GPS lock
However since the rest of the house has no power somewhat of a useless
point. Far bigger concerns at least in the winter.
It really boils down to what you need to do with the solution.
On Fri, Apr 25, 2014 at 4:30 PM, Tom Van Baak <tvb at leapsecond.com> wrote:
> > Hi Everyone,
> > I'm newer to this forum but I really enjoy reading the discussions. I
> > a pretty basic question.
> > I'm wondering why one would chose an Rb Oscillator over a traditional
> > It does not immediately appear there is a phase noise advantage in the
> > Thanks,
> > ~Shane
> Welcome to time-nuts. Good question.
> In some applications the exceptional long-term frequency accuracy and
> stability you get with Rb is more important than the better phase noise,
> smaller size, lower power, better short-term stability, longer lifetime, or
> cheaper price that you get with an OCXO.
> When you buy a new OCXO, it might be accurate to 4 or 5 or 6 digits,
> out-of-the-box. You have to mechanically (screw) or electronically (EFC)
> calibrate it to get closer. If you want, say, 9 digits of accuracy, then
> you may have to re-calibrate it every day or at least once a week.
> When you buy a new Rb, it might be accurate to 9 or 10 or 11 digits,
> out-of-the-box. If you want, say, 9 digits of accuracy, then you may have
> to calibrate it every couple of years.
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