[time-nuts] GPS 1 PPS accuracy limits

Bob Camp lists at rtty.us
Tue Apr 20 16:14:46 EDT 2010


What is their calibration interval and environment?

With GPS you will have the usual "when locked and stable" disclaimer. With
some cost / effort you can get limited holdover at that level. 

For a true good for a year/running autonomously, type spec - you need a
cesium standard. Getting one that will meet a rugged environment spec may be

I'd bet the spec you are looking at has / should have a sub-spec that reads
"when locked to an external reference". The implication being that the
reference is exactly on frequency.  


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of life speed
Sent: Tuesday, April 20, 2010 1:27 PM
To: time-nuts at febo.com
Subject: [time-nuts] GPS 1 PPS accuracy limits

Time Nuts;

I have a customer request for a microwave frequency synthesizer with extreme
accuracy requirements; 4 X 10^-11, or 0.04 PPB.  Obviously this is way out
of quartz oscillator territory.  Is GPS 1 pulse-per-second useable, or do
they need an atomic clock?  Maybe they don't realize what they are spec'ing.


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