脉冲编码可控震源信号设计

Signal design for controllable seismic source by pulse coding

通过脉冲编码技术使震源向地下激发出可人为控制的变步长的脉冲序列,采用解码技术将这种连续多次小能量激发情形的原始地震记录转换为等价的单次大能量激发的地震记录.文中通过数值模拟技术对脉冲编码震源信号地震响应的规律和特点进行了研究.模拟结果表明,脉冲编码信号冲击间隔的增量是压制相关噪声的关键因素,调整冲击间隔的增量对相关噪声的影响要比增加冲击次数对相关噪声的影响灵敏得多,而重复的冲击间隔对压制相关噪声不起任何作用.

With the pulse coding technique, a series of pulses, which are produced by a controllable impact source and have the variable time intervals, are introduced into the ground. The seismic recording from a series of many lowpower impact pulses can be transformed into a recording that is equivalent to the one from high-power impact pulse by using decoding techniques. The characteristics of seismic response to pulse coding signal are investigated by numerical simulating. The results show that the increment in the value of pulse interval between two neighboring impacts in a coded signal is a key factor for suppressing correlation noise. Changing the increment of impact interval is more sensitive to suppressing correlation noise than increasing the times of impacting. But repeated impact intervals do not have any effect on weakening the correlation noise.