中文摘要：

为提高给定数据长度下的相位估计精度，该文提出双向DFT对称补偿测相法。该方法对样本做前向和后向两次DFT变换，再从前、后DFT谱的对称峰值谱位置做谱综合而提取出中心样点的精确相位信息。基于此，推导出了相位估计方差的闭合理论表达式，仿真实验验证了该表达式的正确性，并且证明了该文方法的相位估计方差处于全相位FFT（apFFT）估计法和两参数克拉美罗限（CRLB）之间。该文方法测相精度高，具有广泛应用前景。

英文摘要：

In order to increase the phase measurement accuracy of a given fixed amount of samples, this paper proposes a novel bi-directional DFT symmetric compensation measuring phase method. Through implementing forward DFT and backward DFT on the given samples respectively, the accurate phase information can be extracted from the symmetric peak spectral locations of these forward and backward DFT. Based on this, the theoretic closed-form expression of phase estimation variance of this novel estimator, which is verified by simulation. Moreover, the simulation results verify that the desired phase estimation variance is between all-phase FFT （apFFT） and Cramer-Rao Lower Bound （CRLB） of 2 parameters, thus the proposed method has high accuracy and wide application prospects.