相位舍位对直接数字频率合成杂散特性的影响

The Effect of the Phase Truncation on the Output Spurious Characteristics of a DDS

现代通信系统对频率合成源的技术指标提出了越来越高的要求 ,如相位噪声和杂散抑制等。由于相位舍位会导致直接数字频率合成器 (DDS)的输出产生杂散 ,使其频谱特性恶化。用傅里叶变换方法对在相位舍位情况下的DDS输出频谱的杂散特性进行了理论分析 ,分析结果与实验结果相吻合。

In the modern communication system, it is required that the frequency synthesizer haveing good spectral characteristics, such as phase noise and spurious signal suppression. As we know, spurious noise of a DDS resulted from phase truncation degrades its spectral characteristics. In this paper, the Fourier transform is used to analyse the spurious characteristics of a DDS in the presence of phase truncation, and the experiment results agree with the theoretical results.\;