[time-nuts] Ublox neo-7M GPS
hmurray at megapathdsl.net
Tue Aug 19 14:05:14 EDT 2014
SAIDJACK at aol.com said:
> its not a GPSDO though, not even a simple one :)
> It does not discipline an oscillator. It generates the output by
> mathematically calculating how many phases it has to add/drop in a second,
> then digitally adds/drops/extends/retards the phase of the output clock to
> achieve an average of number of desired clock cycles.
Is there something about the term GPSDO that says I have to do the "D" in the
analog domain rather than the digital domain?
I agree that current technology doesn't give results that are useful for many
applications that currently use GPSDOs. What if the clock ran at a GHz? 10
GHz? Sure, it would have spurs, but would it be useful for some applications?
Is a GPSDO still a GPSDO if the D/A driving the VCXO only has a few bits?
How many bits does it need to be a real GPSDO?
Is a battery powered wall clock listening to WWVB at 2 AM a WWVDO? It's got
a pretty good ADEV if you go out far enough.
These are my opinions. I hate spam.
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