周期测量误差对周期信号相位谱的影响

Influence of Error in Period Measurement of Periodic Signal on Its Phase Spectrum Estimation

从离散傅氏变换定义出发，探索了周期测量误差对周期信号频谱的影响，并推出了各谐波分量的初相位误差与周期测量误差、一周内采样点数、样本长度所包含的周期数和分量阶数之间的简化关系式，便于工程应用。仿真结果表明，该简化关系式适于工程实际应用。

The initial phase of a periodic signal plays an important role in the fault detection of rotary machinery. Based on the discrete Fourier transform, a discussion is made about the influence of an error in period measurement on the frequency spectrum of the periodic signal. Furthermore, a simplified formula, which is convenient for practical use, is presented for the relationship between the error in estimated initial phase and some parameters, including the error in period measurement, the number of periods in a sample length, the number of sampled points in a period and the order of harmonic component. Simulation result shows that the simplified formula is suitable for engineering applications.