Design and Implementation of Local Oscillator Based on DDS and PLL

The development trend of modern frequency synthesizer is high performance and miniaturization,Phase Locked Loop(PLL) frequency synthesizer and Direct Digital Frequency Synthesizer(DDS) are used widely.The basic principle of DDS and PLL,scheme of local oscillator using DDS-AD9954 plus PLLADF4112 are introduced.The focus of this paper is the hardware implementation including system elements,key unit circuit design,phase noise performance of this system and its spurious performance are analysed.At last,experimental results are introduced.