Here is my new Rubidium Frequency Standard. It’s an atomic clock! It has a crystal oscillator disciplined to Rubidium-87 hyperfine transition.
It has an impressive specification:
|1.4×10-11 /√ τ (1s ≤ τ ≤ 100s)
I do not (yet) have any means for verifying its stability and accuracy. A quick test with my frequency meter suggests that it is working correctly. However this test does not tell me much as this frequency standard stability is many order of magnitude better than my frequency meter. I am planning to get a GPS disciplined oscillator for performance comparison.