Modern electronic equipment, like Radar, Test and Measurement, Instrumentation, Avionics, etc. require precision frequency sources with low phase noises. Frequency accuracy and precision can derive from atomic clocks (such as Rubidium or Cesium) or GNSS. In many cases, however, frequency accuracy and precision does not necessarily accompany low phase noise. Similar problems occur when the clock signals distribute over long distances through noisy environments. One example of precision atomic clock-based sources with poor phase noise performance is a Chip Scale Atomic Clock (CSAC).
The goal is to maintain accuracy, precision and long-term stability of the source, while significantly improving the phase noise of the signal. Achieving this goal is accomplished through so called cleanup Modules, based on different types of Quartz Crystal Oscillators.