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基于升频扫描定义,针对瞬时频率随时间呈线性变化的情况,L_1等(1995)提出了一个确定性的纯相移滤波器(PPSF)以消除可控震源地震资料中的谐波畸变。应用PPSF有可能改善谐振畸变的地面压力信号与谐振畸变的可控震源信号间的相关。这种PPSF已成功地应用于实际资料。本文中,我们首先通过对谐波畸变扫描(HDS)的傅里叶相位谱及它的分量进行数值计算,并将它们与相应的瞬时相位进行比较来研究可控震源资料。我们提供了时间域和频率域内谱之间的一些有意义的关系。我们还论证了这些关系将如何对利用PPSF消除谐波畸变的方法起作用。最后,我们给出了利用PPSF消除谐波畸变过程的数学模型。
Based on the definition of up-sweep, L 1 et al. (1995) proposed a deterministic pure phase shift filter (PPSF) to eliminate the harmonic distortion in the seismic data of vibroseis, in view of the instantaneous frequency changing linearly with time. The application of PPSF may improve the correlation between the ground-pressure signal of resonant distortion and the vibratory-induced vibroseis signal. This PPSF has been successfully applied to the actual data. In this paper, we first investigate the vibroseis data by calculating the Fourier phase spectrum of the harmonic distortion scan (HDS) and its components, and comparing them with the corresponding instantaneous phase. We provide some meaningful relationships between the spectrum in the time and frequency domains. We also demonstrate how these relationships will work to eliminate harmonic distortions using PPSF. Finally, we give a mathematical model to eliminate harmonic distortion using PPSF.