衍生于全相位FFT的双子段相位估计法

摘要

To enhance the phase measurement accuracy with a fixed amount of samples,a double-subseg-ment measuring phase method is proposed,which is derived from all-phase fast Fourier transform(FFT).In the proposed method,only the first subsegment and the last subsegment among the N subsegments included in all-phase FFT are taken out,and accurate phase measurement can be finished through synthesizing the phase infor-mation of the peak spectra from these two segments FFT spectrums.Theoretic analysis is also conducted to an-alyze the reason why the proposed method has higher phase measurement accuracy than that of all-phase FFT in noisy circumstance.Moreover,simulation also shows that,when the signal-to-noise rate is not too low,the phase estimation variance of the proposed method is between that of all-phase FFT and Cramer-Rao lower bound CRLB of two parameters,which endows the proposed method with wide application prospects.%为提高给定样本数量下的相位估计精度，提出双子段测相法。该方法是从全相位快速傅里叶变换（fast Fourier transform，FFT）测相法衍生的，只需取出全相位 FFT 包含的 N 路子数据段中的首、尾两个子段，再综合这两个子段的 FFT 谱提取峰值谱相位信息即可完成高精度测相。理论分析了在噪声环境中，所提方法测相精度高于全相位 FFT 测相法的原因。仿真实验表明，在信噪比不太低的场合，双子段测相法的相位估计方差处于全相位 FFT 估计法和两参数克拉美罗限之间，因而具有广泛应用前景。