一种能改善DDS输出精度的技术

Technology of the improvement on the output accuracy of DDS

为改善直接数字式频率合成技术中存在对频率控制字取整造成的实际输出频率和拟产生频率有微小差异的问题.文中对直接数字式频率合成器中的相位累加过程进行了控制,实现了一种可输出精确频率的直接数字式频率合成技术.利用实际输出频率和理论频率之间的相位差变化特性优化设计控制过程.实验结果表明该技术方案有效,能将直接数字式频率合成技术中尾数频率的影响减小至1/104,而控制过程对输出信号的相位噪声和频率稳定度等指标几乎无影响.

In todayS widely used direct digital frequency synthesis technology, there is a slight differencebetween the actual output frequency and the frequency to be generated due to the rounding of the frequencycontrol word. In this paper, the phase accumiulation process in the direct dcontrolled to basically realize a direct digital frequency synthesis technique without the miantissa frequency.The design and control process is optimized by the phase difference variation characterisactual output frequency and the theoretical frequency. Experimental results show that the technical scheme can effectively reduce the influence of the miantissa frequency in the direct digital frequency synthesis technology byncarly ten thousand times, and the control process has a little effect on the phase noise, frequency stability, and other indicators of the output signal.