At HP, it was explained that a primary standard could be built on a desert island containing no frequency standards nor any GPS receivers, etc. and it would be guaranteed by design to meet its spec. It could have adjustments, either operated by a technician or a computer controlled algorithm, but none of them consisted of "setting" the frequency to the correct value using a frequency counter, etc.
It isn't based on accuracy. The reduced performance HP 5062 is still primary, even though the 5061 is more accurate. Similarly, the 5071 is still more accurate, but the 61 and 62 retain their primary status. ADEV is not an issue to qualify for primary status. Rick N6RK On 3/26/2021 2:42 PM, cdel...@juno.com wrote:
In reference to: "It would be cool to say one has a "primary standard", .... So, I think we should be careful with the term, it's get thrown around too lightly." Any of the hobby grade used Cesium standards is actually a Primary frequency standard as it does meet the definition of: A frequency source that meets national standards for accuracy and operates without the need for calibration against an external standard. They ARE able to meet their accuracy specs without calibration against an external standard. The definition does not exclude them. I realize that Metrology usage may be different but the definition makes no judgement as to how performance levels! Cheers, Corby _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
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