基于四项最低旁瓣Nuttall窗的插值FFT谐波分析

快速傅里叶变换(fast Fourier transform,FFT)在非同步采样和非整数周期截断时存在频谱泄漏,无法精确得到谐波参数。为了减少非同步采样对FFT的影响,本文采用四项最低旁瓣Nuttall窗结合双谱线插值FFT进行谐波分析。文章分析了四项最低旁瓣Nuttall窗的频谱特性,提出了基于四项最低旁瓣Nuttall窗插值的分析算法,运用多项式拟合推导出实用的插值修正公式。仿真结果验证了在非同步采样时,该算法与加Blackman窗和Blackman-Harris窗的插值FFT相比具有更高的精确度,更好的抑制了频谱泄漏。

Harmonic analysis based on 4-term minimum sidelobe Nuttall window interpolation FFT algorithm

There is frequency leakage in situation of non-synchronized sampling and non-integer cycle truncation for fast Fourier transform ( FFT) and the high measurement accuracy of harmonic parameters can not be detected .To re-duce the influence of non-synchronized sampling on FFT , this paper adopts harmonic analysis using the 4-term mini-mum sidelobe Nuttall window combined with double-spectrum-line interpolation FFT algorithm .The spectral character-istics of 4-term minimum sidelobe Nuttall window are analyzed in this paper and an algorithm based on 4-term mini-mum sidelobe Nuttall window interpolation FFT has been proposed .The applicable formulas are obtained by fitting of polynomials .The simulation results show that the algorithm has a better detection precision than Blackman window and Blackman-Harris window interpolation FFT algorithms in non-synchronized sampling which will control the spectral leakage more efficiently .