Application of DDS Based on DSP in Rubidium Atomic Frequency Standard

The present status and development of rubidium atom frequency standard are introduced. The main limitation of adopting the phase lock frequency modulation was discussed. On the foundation of analyzing the DDS algorithm, the plan of direct digital frequency synthesis based on DSP was given. Through adjusting the parameter of DDS online, we can obtain the output frequency of the high resolution in the experiment, and aim the excitation transition frequency of rubidium frequency standard at the center spectrum frequency of quantum system automatically. Simultaneously, two output frequencies of DDS haven´t the phase difference. Thus the cost of the rubidium atomic frequency standard is not only reduced, but also its stability is greatly improved.