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针对利用 DFT幅度估计正弦信号幅度因频谱泄漏引起较大误差的问题 ,首先根据 DFT最大谱线的幅度对信号幅度进行粗略估计 ,然后将采样信号分两段再做 DFT,由两个 DFT在最大谱线处的相位得到信号的初始相位 0 的估计值 ,根据 0 估计信号频率与 DFT最大谱线对应的频率的偏差 δ,利用 δ对幅度的粗略估计进行修正 ,得到信号幅度的高精度估计 .Monte Carlo模拟结果表明幅度估计精度大大提高 ,估计方差接近 Cramer Rao下限 .
In order to estimate the amplitude of sinusoidal signal caused by DFT, the signal amplitude is roughly estimated based on the amplitude of the maximum spectral line of DFT. Then the sampled signal is divided into two segments to do DFT. According to the estimation of the initial phase 0 of the signal by the phase at the spectral line, the deviation δ of the frequency corresponding to the maximum frequency spectrum of the DFT is estimated according to 0, and the coarse estimation of the amplitude is corrected by using δ to obtain the high precision of the signal amplitude The Monte Carlo simulation results show that the accuracy of the amplitude estimation is greatly improved and the estimated variance is close to the Cramer Rao lower limit.