A New Method for Repressing DDS Spur Based on Second-order Phase Dithering
Xiaoyong Yang · Electronic Science and Technology · 2011
Direct digital frequency synthesis(DDS) spurious suppression is one of the focuses of current research,in which the phase dithering is a common method of inhibiting phase truncation spurs.This article first introduces the basic principles of DDS and spurious sources,and then analyzes the phase truncation spurious reason and the principles of general phase dithering,and presents an improved method based on second-order phase dithering.A rigorous derivation and proof of the method is made.The study shows that the repressing effect of DDS spur using this method is more significant than the ordinary phase dithering method,which can reach 18dB per phase bits.Finally,the feasibility of the method is verified using MATLAB simulation of the DSP Builder.