Design And Realization Of The Atomic Clock's Digital Control Circuit

Scientific and technological progress and social development propose increasingly high demands on the accuracy of measurement of time. The atomic clock is so far the most accurate time tool. However because of its huge size of the complicated equipment, it is difficult to apply it more widely except to aerospace, astronomy, physics and a few other aspects. In order to expand the scope of applications of atomic clock, its miniaturization and cost reduction is imperative.This article's source is the research of the small atomic clock is based on the CPT (Coherent population trapping) principle and use the MEMS (Micro- Electro- Mechanical- System) technology to realize the atomic clock's miniaturization . This article is focused on the control circuit design and is implemented for the novel small CPT atomic clock; the circuit function is to produce a modulation frequency of 3.4GHz clock signal input to the CPT physical part. Then a weak error signal is extracted from the CPT physical part and fed into the digital control circuit, which will automatically keep the modulation frequency to synchronize with the atomic superfine energy level vibration, then achieve the purpose of the more accurate output frequency.The main research has been done in this article as follows:Firstly, the principles of the atomic clock system and the functions of the controlling circuit in the system has been well understand. Then the control circuit system has been designed and the various parts of it has been confirmed.Secondly, the circuit in details has been designed according to the control circuit system requirements including choosing the chips, understanding the chips'principles and methods , and implementing the circuit design.Thirdly, the circuits have been programmed and tested, and the problems and mistakes in the progress of debugging have been identified. The circuit was improved and simplified according to the problems and mistakes. The effort have been made to continue to streamline and improve the circuit to meet the requirement of the atomic clock system.