基于频谱泄漏抑制的改进FFT宽频测量算法OA

To solve the problem of accuracy degradation caused by spectrum leakage in broadband signal measurement with traditional fast Fourier transformation(FFT)methods,an improved FFT broadband signal measurement algorithm is proposed in this paper.First,the spectrum distribution of broadband signals is analyzed by the Fourier transform theo⁃ry,and it is found that the mismatch between sampling and signal frequencies and the signal truncation effect will cause spectrum leakage.Second,to reduce the effects of spectrum leakage on the spectral accuracy and amplitude,the Nut⁃tall-Kaiser hybrid window and periodic compensation functions are adopted to correct the problem of spectrum leakage,and the convolution window property of the all-phase FFT algorithm is used to suppress the side lobe decay.Finally,the actual signal from a power station in northwest China was utilized to verify the proposed method.Results show that the improved FFT algorithm can not only accurately obtain the information about the amplitude and frequency of broadband signals,but also reduce the spectrum leakage and improve the measurement accuracy.