Effect of Transmitter Current Waveform on TEM Response
详细信息
- 责任者：Chen Shudong (College of Instrumentation and Electrical Engineering ; Jilin University ; Changchun 130026 ; China) ; Lin Jun
- 刊名：Chinese Journal of Geophysics
- 出版年：2012
- 卷期：55(2)
- 关键词：瞬变电磁法 ; transient electromagnetic methods
- 页码：p.709-716
- 图表：7 illus., 17 refs.
- 分类号：1600
- 出版序号：20130472
- issnNo：ISSN0001-5733
- isbnNo：CN11-2074/P
摘要
This paper investigates the effect of different transmitter waveforms on the transient electromagnetic (TEM) system response. For a loop target in free space, the voltage response is derived for waveforms of square, trapezoidal, half-sine and triangular shape. It is found that,for lower conductivity object,every waveform excites almost the same response during on-time and off-time, respectively. Among all waveforms, the maximum response is generated by a square pulse. For low signal to noise ratio (SNR) during off-time, square pulse is usually used for lower conductivity object detection. For higher conductivity object, response sharply decreased with the increase of the conductivity during off-time. While the responses of half-sine and triangular shapes are constant with the increase of conductivity. So the authors concluded that half-sine and triangular shapes are suitable for on-time detection. By properly increasing the base frequency, high SNR and high space resolution can be obtained.