摘要
研究频率合成技术问题,直接数字频率合成(DDS)技术由于固有的输出杂散多且难于预测,限制了DDS技术发展和应用。依据DDS基本原理,针对DDS输出信号频谱质量的相位舍位杂散问题,为了提高分辨率和信号频率稳定性,利用离散傅氏变换法和傅氏变换法,推导出理想DDS输出频谱特性和相位截断杂散分布特性,找出相位截断对DDS频谱分布的影响规律,抑制杂散输出。采用抖动注入法和延时叠加法,在Matlab上进行DDS杂散抑制建模和仿真结果表明效果较好,得到了频谱纯,杂散低,失真小,稳定度好的波形,并证明了两种方法抑制杂散的有效性和可行性。
Direct digital frequency synthesis（DDS） technology is greatly limited because of its inherent spurious outpup which is diffcult to predict.The phase truncation is the key spurious of the output spectrum.The ideal DDS output spectrum and the spurious with phase truncation are presented by the signal analysis method with discrete Fourier transform and Fourier transform and obtain the regular patterns of the phase truncation to the DDS output spectrum.Some method of spurious reduction is analysed and the DDS model is built base on Matlab and FPGA with the phase jitter and delay overlapping.The Simulation result proved that the waveform is ideal and the spurious are suppressed.Experimental result shows that these ways can suppress spurious and are of validity and feasibility.
出处
《计算机仿真》
CSCD
北大核心
2011年第2期397-401,共5页
Computer Simulation
关键词
直接数字频率
杂散抑制
抖动注入
延时叠加
Direct digital frequency
Spurious suppression
Phase jitter
Delay overlapping
