关于大地电磁信号非最小相位性的讨论

Discussion on the non-minimum phase of magnetotelluric signals

由于信号的功率谱仅包含振幅信息而不包含相位信息,因此传统功率谱方法仅能处理最小相位信号,难于适用于非最小相位信号.本文对不同地区的实际大地电磁(MT)信号作了分析,结果表明,不同测点MT信号在Z平面上的零点分布并不全部位于单位圆之内,可以判定MT信号一般具有非最小相位的特点,因此有必要改进传统处理方法,发展新的资料处理方式.实际信号分析,理论和数值模型实验证明,信号的高阶统计量包含其相位信息,因此,高阶统计量方法能够有效处理具有非最小相位特征的MT信号.

Traditional power spectral method can only process minimum phase signal, which is very difficulty to process non\|minimum phase signal due to the power spectrum of signal only contains magnitude information without phase one. This paper analyses practical magnetotelluric (MT) signals of different areas, and the results indicate that not all the zero\|point distributions, lying in Z plane of MT signals of different sites, locate in unit circle. Based on this result, we can judge that MT signals, in general, have the characteristic of non\|minimum phase. So it is necessary to improve traditional processing method, and develop new data processing scheme. The analysis of practical MT signals, theory and numerical model test testify that the higher\|order statistics of signals contain its phase information. Hence, higher\|order statistics method can effectively process MT signals with non\|minimum phase characteristic.