在分析了直接数字频率合成(DDS)工作原理及现有的设计方法中引起DDS杂散的原因后，提出了一种通过改进ROM查表结构消除相位截断效应的设计方法，然后介绍了设计在FPGA芯片上的实现，最后给出了利用MATLAB软件对设计方法进行仿真的结果。

The principle of DDS and the causes of spur are analyzed and a new method for eliminating spur caused by phase truncation error by improving the structure of ROM look-up table is proposed in this paper. Then the authors introduce the implementation of the design in a FPGA chip and give the simulation results of the method using MATLAB software.

TN741