基于非周期伪随机序列的可控震源信号调制技术

Seismic Vibrator Signal Modulating Based on Aperiodic Pseudorandom Sequence

从便于寻优的角度出发,给出了三元非周期伪随机序列的一种定义,提出了基于非周期伪随机序列的可控震源信号调制方法。该方法与二元m-序列调制方法相比,不存在地震数据资源的浪费问题。三元非周期伪随机序列通常比相同长度的二元非周期伪随机序列具有更小的边峰主峰比。地震数值模拟结果表明,将具有较小边峰主峰比的三元非周期伪随机序列调制生成的信号作为地震勘探中可控震源的发射信号,其地震响应剖面的相关噪声要比相同长度的二元非周期伪随机序列调制情形有明显的减弱。

A method to modulate seismic vibrator signals was proposed based on aperiodic pseudorandom sequences given a definition of ternary aperiodic pseudorandom sequence. Compared with binary m-sequence modulation, this method doesn＇t waste seismic data resources. Generally,a ternary aperiodic pseudorandom sequence has smaller ratio of side lobe to main lobe than a binary one. The simulation resuits show that the correlation noises in response section to the seismic vibrator signal modulated by ternary aperiodic pseudorandom sequence with smaller ratio of side lobe to main lobe are obviously weaker than that by binary aperiodic pseudorandom sequence with the same length.