系统的构建及其功率谱和高阶谱的比较

Establishing system to compare power spectrum with higher-order spectrum

1. 中国地质大学地球物理与空间信息学院,湖北武汉 730074;2. 中国石油大港油田公司研究中心,天津 300280

Applied Geophysics Department, China U-niversity of Geosciences, Wuhan 430074, China

根据功率谱等价性或模型多样性原理。具体构建了2个系统:最小相位系统和非最小相位系统。用相同的激励信号作用,结果显示,功率谱密度无法分辨非最小相位信号.丢失了信号中的相位信息.而双谱包含了信号的相位信息。通过对大地电磁(MT)信号分析,表明MT信号一般具有非最小相位性.同样也可确定其他地球物理信号的非最小相位性。这种情况下,如果仍然用功率谱方法处理这种具有非最小相位特征的信号,则会使解释结果出现偏差。为了提高解释结果的精度和可靠性.可以利用高阶统计量(高阶累积量和高阶谱)方法处理地球物理资料。

Based on power spectrally equivalent and multiple of model, this paper presents two systems: minimum phase system, and non-minimum phase system. With same input signal to excite two systems, the results show that the power spectral density of the output can't identify non-minimum phase signal. If using it to process non-minimum phase signal, phase information will be lost. However, the bi spectra of minimum phase and non-minimum phase signals are obviously different, which indicates that the bis-pectral of signals contains the phase information. By analyzing MT signal, the result indicates that MT signal is usually non-minimum phase. Then, geophysical signals usually have the property of non-minimum phase. Thus, using higher-order statistics (higher-order cumulant, higher-order spectrum) to process geophysical data in order to promote the precision and reliability of the results.