[time-nuts] 1 pps correction

Achim Vollhardt avollhar at physik.uzh.ch
Tue Apr 10 09:06:58 EDT 2012

Dear Chris, Bert and all,

for the M12M, I have done exactly this..


It plugs in between the M12M and the carrier board and compensates the 
sawtooth based on the @@Hn information via a delay line. Yes, the uC is 
rather large, but used because available :)

If anybody is seriously interested, I am happy to hand over layout and 
source code. Please contact directly.


> Chris
>  do you or any one else have a micro controller and code for  such an 8 pin
> solution? The rest I would know how to do.
> Bert Kehren
> In a message dated 4/7/2012 12:12:40 P.M. Eastern Daylight Time,
> albertson.chris at gmail.com writes:
> The  simplest way to do this is to use a "standard" GPS and let if
> drive a  GPSDO.  Yes you can try and build a copy of a T-bolt but how
> many  engineering ours do you think Trimble spent on that?  Well over a
> man  year I'd say and few people have the range of skills needed to do
> it all  themselves.
> If you want to use the sawtooth data in the GPSDO then  you'd need a
> one of those very small 8-pin micro controllers.  It  could "tap" the
> serial line and listen for the sawtooth correction and then  output a
> voltage on an analog pin.   The sawtooth correction does  not change
> very fast so the bandwidth is low enough for something like an  AVR or
> PIC.  This uP would have only one function so the software  would be
> easy
> I think you'd use the analog sawtooth voltage to slightly  bias the
> phase detector.

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