数据延拓式相关的相位差测量方法及验证

Research and validation on improved correlation method for phase difference measurement based on data extension

为提高相关法在非整周期采样情况下的相位差测量精度,提出一种数据延拓式相关的相位差测量方法。通过分析相关法相位差测量存在误差的根本原因,得出抑制相位差测量误差的方法:首先,对采样信号作周期预估计;然后,对数据长度是否整周期进行判断,对非整周期的数据长度作整周期数据延拓处理,使相关计算的长度恰好或者近似为整周期,从而达到提高相关法相位差测量精度的目的;最后,利用相关法相位差计算公式计算得到信号的相位差。对振动、测试系统中常出现的加性高斯白噪声信号的实验表明:该方法可以显著提高相位差测量精度。

In order to improve the precision of the correlation method for phase difference measurement under non-integer period sam- pling circumstance, an improved correlation method for phase difference measurement based on data extension is proposed. The generation reason of phase difference measurement error based on correlation method is analyzed, and the method for restraining phase difference measurement error is deduced. Firstly, the period of the sampled signal is estimated. Then, if the data length matches integer periods or not is judged, and the non-integer period sampled signal is extended to an integer period sequence, which makes the data length equal or close to integer periods for correlation calculation, thus the precision of the correlation method for phase difference can be improved. At last, the phase difference could be calculated using the calculation formula of correlation method. Experiments on the signals commonly existing in vibration and test systems deteriorated by additive white Gaussian noise were conducted; and the experi- ment results show that the proposed method can improve the precision of phase difference measurement obviously.