离散频谱四点能量重心校正法及抗噪性能分析

在对比离散频谱能量重心法采用不同点数时的频率、幅值和相位校正精度的基础上提出了4点能量重心校正法,推导了高斯白噪声背景下单频率谐波信号采用4点能量重心法进行频率、幅值和相位校正的统计方差公式,通过仿真计算验证了其正确性.分析对比了采用不同点数进行能量重心校正时的优缺点,建议在工程中采用Han-ning窗4点能量重心法进行谐波信号离散频谱校正.

Anti-noise performance of energy centrobaric correction method using four points for discrete spectrum

The energy centrobaric correction method is based on the fact that energy center of symmetric window function is the center frequency of the window in discrete spectrum analysis. Since the Hanning window energy is mainly concentrated on the main-lobe, an approach of utilizing 4 spectral samples in the main-lobe of the Hanning window to correct spectral parameters is proposed. Analytical expressions of the estimator variances for frequency, amplitude and phase correction are derived; and simulation results confirm the validity of the presented method. The properties of utilizing different quantity of spectral lines in the energy centrobaric correction are analyzed with respect to their noise sensitivity. Comparing with those using 3 or 5 spectral samples in the main-lobe of the Hanning window, the method of utilizing 4 spectral samples provides superior accuracy in parameters estimation, which is more practical in engineering application.