[time-nuts] New timing receivers?

Hal Murray hmurray at megapathdsl.net
Sun Apr 27 23:43:44 EDT 2014


jim at jtmiller.com said:
> I spent some time reading the uBlox-6 documentation. I found the TIM-TP ubx
> message and format. I see that there is also the ability to feed back to the
> uBlox-6 time shift info for the PPS in 1ns increments.

> Does it make sense to feed the TIM-TP info back this way to provide
> correction?

(I'm reading between the lines, so this may be totally wrong.)

The uBlox-6 has a free running osc.  If it wasn't free running, it would be a 
GPSDO.

There is an adjustment for antenna cable length.

If you tweak the antenna length adjustment, you can make the sawtooth offset 
be 0 at any particular sample.  But then the osc will drift and the sawtooth 
will tell you how much it has drifted.


> Or is an external delay line or TIC plus software the only way? 

If it was as simple as you would like, the uBlox guys would have done it 
already.


-- 
These are my opinions.  I hate spam.





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