[time-nuts] Thunderbolt? (re simple gpsdo.)

[Hal Murray]

> "What is the simplest design for a GPSDO that uses only the PPS signal from
> a modern GPS?" 

Some sort of oscillator with a voltage control.
CPU with a timer/counter that can capture the PPS.
DAC.
Software.

Drive the CPU from the osc so you can count cycles between PPS pulses.  Use 
the DAC to adjust the frequency.  Build a low pass filter in software.

The DAC may be the tricky part.  You would like lots of bits, but it also has 
to be stable.

With a given DAC, you can get finer control by trading off range.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.