[time-nuts] yet another GPSDO design, or so

[bg at lysator.liu.se]

Hi,

>> What would be easier to try is to replace the gps internal Tcxo with
>> an external ocxo, but you have to generate the frequency the gps is
>> using, such as 26 MHZ and do some soldering on the gps itself.
>
> Yes, that would be an idea. But it's not that easy. I dont know
> how the control loop in the LEA-6 works and whether they are actively
> changing the TCXO frequency. If they are, i would need to provide
> a VCO that is stabilized, either in form of an seperate OCXO or by
> locking/syncinc the VCO to my 10MHz OCXO.

Some manufacturers are fine adjusting their oscillator. But I think the
majority are letting the oscillator free run. Then the software clock
inside the GPS (sometimes called receiver time) will be reset to remain
within +- some limit compared to GPS time, +- 1ms is a common choice.

--

   Björn