[time-nuts] Is it Hz or MHz ?

Kit Scally kitscally at iprimus.com.au
Mon Jun 2 03:28:48 EDT 2014


Team Nutters,
 

GPSDO's are often specified for stability as so many parts per x.  Using a
Symmetricom 8040C as an example, this has a quoted accuracy of typically
5E^-11 at shipment.  Ageing (monthly and yearly) and ADEV stability rates
for 1, 10 & 100 seconds are also given. This particular device as 1, 5 and
10 MHz outputs.

The question - is this "accuracy" with respect to 1Hz - or 10MHz ?  If the
latter, then the accuracy figures quoted needs to be modified by 10^6 (Hz to
MHz) to get a feel for the actual frequency changes at 10MHz.

Glossies of many GPSDO manufacturers seem deathly silent on this point, so
clearly, "something is assumed".  I have seen an oscillator comparison chart
by Meinberg (a German company) that in their comparison chart, the accuracy
references need scaling to relate to 1Hz.
 
Appreciate some advice and/or direction on this before madness overtakes me
!
 
 
Kit 
Canberra
Australia



More information about the time-nuts mailing list