Meaning
Atomic frequency standards utilizing the transition between energy levels of rubidium atoms provide high stability and low drift over extended periods. Long-term accuracy is achieved through the interaction of a microwave signal with rubidium vapor contained in a small cell. A rubidium oscillator offers a level of precision that is several orders of magnitude better than a standard temperature-compensated crystal oscillator.
Frequency Stability
High precision makes the device a primary choice for telecommunications base stations and grandmaster clocks that require a reliable frequency reference. Using a rubidium oscillator ensures that a network remains synchronized even if the connection to a primary time source such as GPS is lost. The capability of the device is measured by its aging rate, which is typically much lower than quartz-based alternatives.
Warmup Time
Reaching a stable operating frequency requires the internal rubidium cell to be heated to a specific temperature, a process that can take several minutes. Initial operation requires the frequency provided by the rubidium oscillator to be treated as unreliable for high-precision applications. Operators must wait for the device to reach thermal equilibrium before using it to calibrate other instruments or to serve as a primary network clock.
Holdover Performance
Sustaining the correct time during a loss of reference signal is possible because the internal atomic reference continues to oscillate at a predictable rate. This performance allows for several hours or days of operation within a required accuracy window.
