Long-term frequency stability improvement of OCXO using CSAC

In this paper we introduce long-term frequency stability improvement of Oven Controlled Crystal Oscillator (OCXO) using Chip Scale Atomic Clock (CSAC). Compared to OCXO, the main disadvantage of the CSAC is their higher phase noise; however the CSAC features with better long-term frequency stability, much lower power consumption and much faster warm-up.