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采用短时单频脉冲震源的浅地层剖面,记录的波形数据空间假频较严重。因其信号具有频率高、频带窄的特征,通常利用Hilbert变换提取瞬时振幅属性(信号包络)供解释使用。但瞬时振幅均为正值,在进行构造解释时不方便使用。本文提出在对浅层剖面资料提取瞬时振幅的基础上,计算瞬时振幅的微分并配合滤波的方法,实现高频窄带浅地层剖面资料的一种频移处理。该方法把高频窄带的多周期信号变为低频带宽的单周期信号,有效扩展了倍频程并消除假频。应用在南海浅地层剖面资料处理中,资料处理后更利于构造解释。
Using shallow stratigraphic section of short-duration single-frequency pulse source, the spatial frequency of recorded waveform data is more serious. Because of its characteristics of high frequency and narrow frequency band, Hilbert transform is usually used to extract the instantaneous amplitude property (signal envelope) for interpretation. However, the instantaneous amplitudes are both positive and inconvenient to use when interpreting the structure. In this paper, based on the analysis of instantaneous amplitude of shallow section data, the differential of instantaneous amplitude is calculated and matched with the filtering method to realize a frequency shift processing of high frequency and narrowband shallow stratum profile data. The method changes the high-frequency narrowband multi-period signal into a low-frequency bandwidth single-period signal, effectively expanding the octave and eliminating the aliasing. Applied in the South China Sea shallow formation profile data processing, data processing is more conducive to structural interpretation.