地震数据采集系统谐波畸变测试方法研究

Testingmethod for harmonious distortion of seismic data acquisition system

1. 长江大学电信学院，湖北荆州434023;2. 东方地球物理公司装备事业部，河北琢州07275

Electronics & information College of Yangtze University, Jingzhou 434023, China

谐波畸变特性是遥测地震数据采集系统的一项重要性能指标,直接影响地震数据采集的质量。现代地震数据采集系统的谐波畸变指标已高达(2～5)×10-6范围,因此无法用一般的电子仪器进行测试,而地震仪器种类的繁多和统一评价标准的缺乏也给仪器的鉴定、校准和维护造成困难。为此,从谐波畸变的基本定义和物理概念出发,针对地震数据采集系统的具体情况,采用模拟和数字信号处理技术对测试谐波畸变的方法进行了探讨,给出了准确测试必须满足的条件,提出了一种实用有效的测试方案。根据信号处理理论,详细推导了谐波畸变的频域计算公式,为解决计算过程中的谱泄漏问题采取了加时窗措施,并探讨了其对谐波畸变指标计算结果的影响。

The Harmonious Distortion characteristic of telemetry seismic data acquisition systems is an important performance index, which affects the quality of seismic acquisition data directly. The level of this performance index for advanced seismic instruments is up to as high as 0. 0002% to 0.0005% at present. It is difficult to authenticate, calibrate andmaintain telemetry instruments for lacking of uniform appraising standard for harmonious distortion test. Starting from the basic definition and physicalmeaning of harmonious distortion, this paper researches themethod of testing harmonious distortion for telemetry seismic instruments by using analog-digital signal processing technique. It points out the conditions for accurately testing harmonious distortion and gives a useful test scheme. Based on signal processing theories, we deduce the calculating formulae of harmonious distortion in frequency domain in detail. It also illustrates the necessity and the effect of window function on the calculating accuracy of harmonious distortion.