组合扫描压制谐波畸变

Using array sweeping to suppress harmonic distortion.

在可控震源采集过程中 ,由于地表条件不同 ,机械驱动装置的非线性及震动装置与大地的耦合问题 ,会产生不同阶次的谐振干扰信号 ,这种谐振干扰信号与基波信号在频率上呈倍数关系 ,混杂于原始记录中。对谐波干扰压制的通常做法是进行变相位扫描 ,利用不同于各次子扫描的相位 ,使谐波干扰在相关求和中得到压制。本文介绍一种压制谐波干扰的方法——组合扫描。该方法的谐波干扰随扫描频宽的降低而减少 ,当扫描频宽达到一倍频程时 ,谐波干扰消失。利用组合扫描压制谐波干扰的基本思想就是合理地设计各个子扫描频宽 ,达到消除谐波干扰的目的。

In a process of acquisition by vibroseis,becau- se of different surface conditions,the non-linear nature of mechanic driven unit and the coupling issue between vibrator and ground resulted in signals of harmonic interference in different order that are multiple relation with the signal of basic wave in frequency,which are mixed in raw records.The common methods for suppression of harmonic interference is to carry out phase-changed sweeping,using the phases different to each sub-sweeping to suppress harmonic interference by correlation summation.The paper introduced a new method for suppression of harmonic interference,that is array sweeping method.The harmonic interference reduced with decrease of the width of sweeping frequency band,when the sweeping frequency band reached an octave,the harmonic interference disappeared.The basic idea using array sweeping to suppress harmonic interference is to reasonably design each sub-sweeping frequency band that can reach the goal of elimination of harmonic interference.