DDS信号的杂散及抑制分析

DDS（直接数字频率合成器）技术由于有诸多优点而得到广泛的应用。但因其固有的数字特性，使其输出信号存在大量的杂散，如何抑制DDS技术产生的杂散问题，是当前研究的热点问题之一。文中在介绍DDS工作原理的基础上，分析了其输出频谱杂散的来源，进而提出了几种抑制杂散的方法，通过加扰动源破坏杂散的周期性，压缩数据和增大ROM的相对容量等，有效地改善了DDS频谱质量，对基于DDS技术的频率源的设计有一定的实用性和指导意义。

Analysis on Restrain Dispersion of DDS Signals

DDS has been used widely because of its so many advantages. However, its inherent digital feature causes its output signal have much spurious signals. How to limit the spurious signals caused by DDS technology is one of the hot points at present. This paper analyses the source of DDS output spectrum dispersion and proposes several ways to limit dispersion basing on DDS work principle. The quality of DDS Specturm can be significantly improved through adding a distrubing source to disrupt the periodicity of Spurious Signals, compressing data and enlarging the relative capacity of ROM. All of these methods have practicality and guiding role to the design of frequency source based on DDS technology.