全相位FFT相位测量法

The Measuring Phase Method of All-phase FFT

为精确测出采样序列各样点的相位值,本文深入研究了全相位FFT(简称apFFT)的相位谱特性,严格证明了apFFT的相位不变性,基于此提出了apFFT相位测量法。此法无需借助任何频谱校正措施即可精确测量出相位值,因而计算量小。仿真实验证明此法在无噪时的精度比第1类相位差法高出5个数量级,在信噪比较大时的均方根误差仅为第1类相位差法的1/4～1/3。

To measure sampled sequeces＇ phase values accurately, the phase spectrum of all-phase FFT（ apFFT for short） is deeply studied in this paper, and apFFT＇s property of phase invariam is strictly proved. Thus the apFFT measuring phase method is proposed,which can achieve high-accracy phase measurement without any correcting sepctrum operations that the computation amount is decreased greatly. Simulation experiment proves that the measurement accuracy of the proposed method is 5 amount levels higher than that of the type-1 phase difference method in noiseless circumstances, and the mean square error is only 1/4 - 1/3 of the one of type-1 phase difference method in high-SNR circumstances.