Design of Servo System in Rubidium Atomic Frequency Standards with Non-integer Voltage Controlled Crystal Oscillator

This paper introduces a new kind of servo circuit system for the miniaturized Rubidium Atomic Frequency Standards (RAFS). Using a 19.984466MHz non-integer Voltage Controlled Crystal Oscillator (VCXO) in a servo system, it can eliminate the need of fractional frequency synthesizer. On the foundation of analyzing the scheme and performance, the design of frequency conversion module for the servo system is given. The servo system applies to the rubidium physics package and a locked closed-loop can be realized. The resulting frequency stability has reached the level of common commercial RAFS.