Development of frequency synthesizer based on DDS+PLL

Phase Locked Loop (PLL) and Direct Digital Frequency synthesis are used widely in the modern frequency synthesis technology. They have their merits and disadvantages respectively. It is feasible to combine the two methods to perform their merits and overcome their disadvantages. The mode of DDS driving PLL is presented to design the frequency synthesizer. The focus of this paper is the hardware implementation, including system elements, key unit circuit design, and phase noise performance of this system is analyzed. Finally, experimental results, which satisfy the design requirements, are introduced.