[time-nuts] DDS in GPSDO design?

[Magnus Danielson]

On 05/28/2012 12:08 AM, Michael Tharp wrote:
> Greetings,
>
> I've been pondering topologies for a custom GPSDO design and two obvious
> choices seem to present themselves. The first, and seemingly more
> popular by far, is to use a "pullable" oscillator as many OCXO and Rb
> oscillators are and discipline it using a slow but precise DAC. But
> unfortunately my Rb is not pullable so I would have to get another
> oscillator. So I have a very stable but off-spec local oscillator, which
> has to somehow be combined with the pulse-per-second from the GPS. If
> there's a palatable analog way to do this, I'd love to hear, because it
> would probably be simpler than the other idea.

How far off? What Rb do you have?

Most Rb:s not having a EFC input should be possible to modify for EFC in 
one way or another, since the C-field needs to be applied regardless.

Cheers,
Magnus