Analysis of Spurs in DDS Due to The Phase-Truncation
Teng Long · Signal Processing · 2009
From the nature of the Phase-Truncation-Error in a Direct Digital Synthesizer(DDS) system,using the small angle approximate calculation,and the theories in time-domain sampling,frequency-domain sampling and modulation as well,a closed form expression of DDS' s spectrum has been deduced,including the number of spurs,the amplitude of each spurs and the position of each spurs.Then,an algorithm has been proposed to predigest the procedure of calculating the spectrum of DDS output.Furthermore,the calculation precision of amplitude can be controlled by increasing or decreasing the times of overlapping.The Matlab simulation has proved that both the procedure of deduction and the algorithm are correct.