The XPRO leverages over 35 years of proven rubidium atomic physics with ad vanced digital electronics architecture to provide an exceptionally stable oscillator that meets the most demanding performance requirements. The XPRO is designed for long operating periods without maintenance (long-life rubidium lamp and extended crystal control range). With a 5.0 × 10–11 per month aging, the oscillator will maintain 1.0 × 10–9 frequency accuracy for 10 years or longer without recalibration.

A low aging rate option is available for XPRO that will provide 1 × 10–11 per month aging, resulting in an even more robust reference source.