一种基于DDS和PLL技术本振源的设计与实现

Design and Implementation of Local Oscillator Based on DDS and PLL

现代频率合成技术正朝着高性能、小型化的方向发展,应用最为广泛的是直接数字式频率合成器(DDS)和锁相式频率合成器(PLL)。介绍直接数字频率合成器和锁相环频率合成器的基本原理,简述用直接数字频率合成器(AD9954)和锁相环频率合成器(ADF4112)所设计的本振源的实现方案,重点阐述了系统的硬件实现,包括系统原理、主要电路单元设计等,并且对系统的相位噪声和杂散性能做了简要分析,最后给出了系统测试结果。

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 PLL- ADF4112 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.