Spectrum Analysis of Spurious Signals in Direct Digital Frequency Synthesizer Due to Phase Truncation
Deng Pan · Radar Science and Technology · 2009
Spurious characteristic restricts the application and development of direct digital frequency synthesizer(DDS) technology.There are several sources of spurious signal:phase truncation,amplitude quantization,DAC's non-ideal characteristics,etc.This paper mainly analyzes the influence of phase truncation on the output spectrum of DDS.Firstly this paper converts arbitrary frequency control word(FCW) into one via discrete Fourier transform,and then analyzes the output spectrum of DDS in the presence of phase truncation from DDS output sequences.The output spectrum algorithm of DDS is exact and simple.