The Design Of Frequency Convertor In Atomy Frequency Standard

Atomic Frequency Standard is the frequency and time benchmark of space technology and time awarding system , directly determining the quality of satellite communications. The veracity and stability of AFS are the most pivotal performance . The paper chief ly copes with researching of the loop equation of servo system of AFS,and realization of frequency transforming stage, traversing the design , optimizing and validating of frequency transforming stage. Servo loop equation's analyzing is highly complex, and the paper propriety predigest all part of servo system, detaching the quanta part which is hard to analyse to two part : quanta frequency discriminator, and controlled oscillator. So, a predigesting equation is educed and it's balance working point is got by schema. AFS frequency transforming stage have very strict require, which always is the bottle-neck of design of AFS . The paper compares several kinds of plan, analyses their merit and flaw , finds a new plan which based on FPGA+DDS and have the strongpoint of highly veracity , low spur , low noise, and realize the new plan which is proved to upgrade the whole system performance . The paper researches the software and hardware realization, gives the layout of hardware and flow chart of the software, designs a usable system and gives a detailed testing, and offers some thinks about farther research. At the same time, the paper gives the software and hardware realization and testing curve of the other frequency transforming stage using in AFS The system has been used in products of sim company, and gain good effect.