基于三次样条函数的加Rife—Vincent(Ⅲ)窗FFT插值算法

The Rife—Vincent(Ⅲ) window interpolation FFT algorithm by using cubic spline function

对于插值FFT算法,窗函数类型和宽度是影响计算精度的主要原因。Rife—Vincent(Ⅲ)窗计算精度高,但其频率修正系数公式和复振幅的插值修正函数过于复杂,直接计算运算量大,影响了它的应用。为了减小加Rife—Vincent(Ⅲ)窗插值FFT算法的运算量,采用三次样条插值函数的有效形式计算频率修正系数和复振幅的修正系数,这些公式简单,计算量小。且在分段处连续,分段处的计算值为精确值,仿真计算结果表明,基于三次样条插值函数的加Rife—Vincent(Ⅲ)窗插值FFT算法具有很高的精度。

The window size and the window type are the main factors influencing the analysis precision of the interpolated FFT algorithm. The measuring precision of the Rife--Vincent（m） Window Interpolation Algorithm is high,but the correction formula for frequency and complex amplitude is too complicated , and it has large amount of computation. Therefore it has very limited application.In order to reduce the computational complexity for the Rife Vincent（Ⅲ） window interpolated Fast Fourier Transform algorithm, the effective form of cubic spline function is adopted to calculate correction factor for frequency and complex amplitude.The formula is simple and has less amount of calculation. Furthermore, it is continuous at the piecewise point where it has a precise value. The simulation and computed result shows that the Rife--Vincent（Ⅲ） window interpolation algorithm by using cubic spline function has high precision.