[time-nuts] GPS Locked and Unlocked Performance Comparison

SAIDJACK at aol.com SAIDJACK at aol.com
Wed Feb 13 17:10:52 EST 2008

Hello Tom,
Bruce mentioned there is a validity bit that can be checked for holdover. I  
wonder if a small micro can be used to hold the EFC voltage steady without 
much  effort. Or maybe using Super-Caps in the loop filter?
Or maybe use one of those new 24 bit Sigma-Delta ADC/DAC chips to capture a  
24 bit word (ADC) and feed that to the 24 bit DAC during holdover. Kind of a 
24  bit high-precision sample-and-hold circuit.
It would be a shame to have such a good OCXO performance go unused during  
short hold-overs. Interesting technical challenge.
In a message dated 2/13/2008 11:54:08 Pacific Standard Time,  
tvb at LeapSecond.com writes:

The  Miller design doesn't support holdover. You can either
run it free (using  JP1, see earlier mail) or run it GPS-locked.
I think the PLL is all of one  gate and an RC filter so there's
nothing to "hold" the EFC. See his web  site for details.

**************The year's hottest artists on the red carpet at the Grammy 
Awards. Go to AOL Music.      

More information about the time-nuts mailing list