摘要
对传统DDS技术由相位截断误差引起的杂散,信噪比及频率分辨率、相位分辨率进行了分析,并在此基础上对传统DDS结构进行了优化,优化后的DDS相位累加器的溢出值可以任意设定,并以溢出信号作为正弦表地址发生器的时钟,一个正弦周期采样点数也被设置成360的整数倍而不是2的整数幂,从而使得频率分辨率、相位分辨率是10的整数幂,不存在尾数,提高了DDS输出频率及相位的准确性。通过合理选择采样点数、正弦值二进制位数有效减小了由相位截断误差引起的杂散,提高了信噪比。在优化DDS基础上设计了电力标准源,电压电流相对误差在0.02%左右,频率绝对误差在10-5 HZ以下,实验数据证明优化DDS精度高,满足设计要求,且结构简单,易于实现。
The traditional DDS structure is optimized on the base of the analysis of the spurs caused by phase truncation, SNR, frequency resolution and phase resolution in DDS. The overflow value of optimized DDS phase accumulator can be set arbitrarily, and the overflow sig- nal is used as the clock of sine table address generator. The number of sampling points is set to an integer multiple of 360 instead of 2 to the power n, thus, the frequency resolution and phase resolution are 10 to the power n, there is no mantissa and the accuracy of frequency and phase is improved. Through the reasonable selection of sampling points number and sine value bits number, the spurs caused by phase trun cation is effectively reduced and the SNR is raised. The power standard source is designed on the base of optimized DDS, the Relative Error of voltage and current is about 0. 02%, the absolute error of frequency is under 10 SHz. The experimental data proves that the accuracy of the proposed DDS is high and meets the nerformance reuuirements, and the optimized DDS structure is simple and is easy to achieve.
出处
《计算机测量与控制》
北大核心
2013年第10期2841-2844,共4页
Computer Measurement &Control
基金
江苏省高校自然科学基础研究面上项目资助(项目编号:11KJB470002)
关键词
标准源
DDS相位截断误差
频率分辨率
相位分辨率
精度
standard source
DDS
phase truncation error
frequency resolution
phase resolution
precision
