新的高精度数字相位差测量方法

A new measurement approach of high precision digital phase difference

在虚拟仪器的基础上,提出了一种新的测试相位差的方法。利用高速数据采样技术对双通道被测信号进行采集,得到高密度的被测信号波形数据,通过对被测信号数据的分析,得到近似的被测信号零相位过零点位置;然后,通过B样条函数在过零点位置附近进行插值处理,得到高精度的零相位过零点位置,进而得到高精度的相位差。仿真实验结果表明,采样频率越高、被测信号频率越低,则测量误差越小,反之,误差增大。通过B样条插值可以得到近似等精度的相位测量误差。在数据采集中含有较大噪声时,采样频率过高,则过零点位置判断容易出现错误,导致180°的相位错误。

On the basis of virtual instruments,a new approach of measuring phase difference has been developed.The approach is that with the high speed data acquisition system,the data of dual channels measured signals are acquired.Based on the data,the approximate position of cross zero＇s phase can be made sure.Then,through inserted value processing of the B-spline function around the position of cross zero＇s phase,the position of higher precision cross zero phase is figured out.According to the position,the high precision phase difference can be calculated.The simulation experimental results indicate that the higher the frequency of data acquisition and the lower the frequency of measured signal,the lower the measured error.On the contrary,the measured error increases.Through the approach of B-sample inserting value,close to the uniformity precision phase difference measurement can be got.Because of signal with strong noise,if the frequency of acquired data even is too high,there may be errors in the determination of zero phase position,resulting in the phase error of 180 degree.