基于Nuttall自卷积窗的改进FFT谱分析方法

Spectral Analysis Method Based on Improved FFT by Nuttall Self-Convolution Window

建立性能优良的窗函数是提高频谱分析准确度的关键。本文用Nuttall窗进行时域卷积运算构建Nuttall自卷积窗,具有旁瓣性能随卷积次数增加而迅速提升的优点;提出基于Nuttall自卷积窗的改进FFT谱分析方法,采用最小二乘法推导离散频谱插值多项式,建立谐波参数准确求解算法;通过仿真实验验证Nuttall自卷积窗及改进FFT谱分析方法的有效性和准确性。

The window with good side lobe behavior is the key factor for the improvement of accuracy of spectral analysis. This paper proposes the Nuttall self-convolution window(NSCW), which is constructed by the self convolution of Nuttall window in time domain. The NSCW has the advantage that its sidelobe behavior is improved rapidly with the increasing of times of self convolution. The Novel spectral analysis based on improved FFT by Nuttall self-convolution window is presented, where the spectral interpolation polynomial is deduced based on the least square method and the calculation of harmonic parameters is then obtained. The effectiveness and correctness of the proposed method are shown by the simulations.