基于多次互相关的非整周期信号相位差测量算法

Research on phase difference measurement algorithm for non-integer period sampling signal based on multi-layer correlation

针对工程实际中频率未知情况下存在相位差测量精度较差的问题,提出一种基于多次互相关的非整周期信号相位差测量算法:首先采用自适应格型陷波器进行滤波,以求信号频率;然后对滤波后的原2路增强信号分别进行希尔伯特变换,产生具有90相移的2路相移信号;并利用估计出的信号频率产生具有90相移的2路参考信号;将原2路增强信号和两路相移信号分别与2路参考信号进行相关运算,再利用相关和正弦函数的一些性质即可得到相位差的计算公式。实验结果表明,该算法测量精度不受采样是否整周期的影响,能实现相位差的动态检测;与传统算法相比,该算法测量精度更高,抗噪性能更强,更具鲁棒性和普适性。

Aiming at the poor precision problem in phase difference measurement with unknown frequency in engineering practice, a new method for non-integer period sampling signal phase difference measurement based on multi-layer correlation is proposed. Firstly, a lattice adaptive notch filter is applied to filter the signals and estimate the frequency. Then, the Hilbert transformation is conducted on the two filtered enhanced signals to generate two phase shifted signals that have 90° phase shift. And then, two reference signals that have 90° phase shift are generated using the estimated signal frequency. At last, the correlation functions of the original enhanced signals ＆ two phase shifted signals and the two reference signals are directly computed, certain properties of correlation and sine function are adopted to obtain the computational formula of phase difference. The experiment results show that the measurement accuracy of the proposed method is not affected by whether the sampling is in integer periods or not; and the method can achieve dynamic phase difference measurement. Compared with traditional methods, this method has higher measurement accuracy and stronger anti-disturbance capability, and has good robustness and universality.