用hanning窗的插值FFT算法，适用于电力系统信号的谐波分析,Hanning window with interpolation FFT algorithm, applied to power system harmonic analysis signals

用窗函数（矩形窗、汉宁窗、海明窗和布莱克曼窗）法设计FIR数字滤波器-Using the window function (rectangular window and hanning window, hamming window and blackman window) method to design FIR digital filter