基于Nuttall窗插值FFT的标准源谐波分析算法

Standard Source Harmonic Analysis Algorithm Based on Nuttall Window Function and Interpolation FFT

电力标准源是用于输出电力仪表测试的基准信号,其输出精度主要取决于反馈检测精度。采用FFT对标准源输出进行谐波分析时,很难做到同步采样和整周期截断,由此造成的频谱泄漏将导致谐波分析时存在较大的误差。针对上述问题,基于插值算法的原理,提出了4项3阶Nuttall窗函数与双峰谱线的插值算法,给出了谐波幅值、相位和频率的修正公式。仿真和实验结果证明所提算法能够有效抑制频谱泄露,显著提高标准源输出精度。

The power standard source is used to outputting standard signals for power instrument testing, and it＇s output accuracy mainly determined by the feedback accuracy. There are difficulties in performing synchronized sampling and integral period truncation when analyzing harmonic of standard source output with the Fast Fourier Trans-form （FFF）, this will cause frequency leakage problems, a dual spectral lines interpolation algorithm and bring harmonic analysis a big error. Aiming at the above for four item three orders Nuttall window are proposed in this paper based on the principle of the interpolation algorithm, and the correction formulas of the harmonic amplitude, phase and frequency parameters are obtained corresponding. The simulation and experiment results have verified that the proposed algorithm can effectively suppress frequency leakage, obviously improve the output accuracy of standard source.