[ntp:questions] Onboard Local Oscillator Change Improvements

John Ackermann N8UR jra at febo.com
Tue Oct 9 14:11:51 UTC 2007

Eric.Jones wrote:
> Alternatively to Harlan's suggestions, there are a few DIY alternatives 
> also if you are so inclined...
> TAPR has a nice clock-generator kit with an ICS525 chip that can use an 
> external GPS signal rather than a crystal:
>   http://www.tapr.org/kits_clock-block.html

Thanks for the plug (I'm the ClockBlock designer) but this isn't 
accurate.  The Clock-Block requires an input clock signal in the HF 
range and won't work with a PPS signal.

However, a TAPR Reflock II (http://www.tapr.org/kits_reflock_ii.html) 
could sort of do this -- it can steer an oscillator to GPS via PPS 
signals, and that oscillator need not be at something simple like 10 
MHz; it could operate directly at the motherboard's clock frequency.  So 
you would still need to provide a piece of decent-quality quartz in the 


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