一种改善MT低频数据质量的方法及其应用

电磁干扰是影响大地电磁测深方法（MT）数据质量的主要因素。目前，除从仪器电路上考虑压制50Hz的工业干扰外，主要的压制干扰的方法为近，远参考的ROBUST技术，它对高频电磁干扰或随机干扰有明显的压制作用。但在强干扰地区（通常具有很强的低频电磁干扰，如长，短脉冲和方波等低频干扰），低频数据的质量仍然很差，这是因为在低频数据处理时，强的低频电磁干扰使得级联分样后的数据发生了强的崎变，与实际的有用信号相差甚远，从MT时序数据出发，提出了应用小波变换的方法，重组低频干扰并加以消除，达到提高信噪比的目的，经实际资料处理证明，此方法效果明显。

A METHOD TO ENHANCE QUALITY OF LOW - FREQUNCE MT DATA AND ITS APPLICATION

Electromagnetic disturbance is one of primary factors affecting data quality acquired by MT. In addition to suppressing 50Hz industrial dis-turbance by apparatus circuits, the main method to suppress the disturbance is the near - remote reference Robust technique which effectively suppresseshigh - frequency electromagnetic disturbance or random disturbance. However, it is difficult to enhance data quality in the area affected by strong low -frequency electromagnetic disturbances like long or short impulses and rectangle waves. Those cause series - related decimated data strong aberrant duringthe data processing, and the data have much difference with the usefu1 signals in practice. Based on the time - order MT data, 1ow-frequency disturb-ance signals are reconstructed and eliminated using wavelet transformation in order to increase s/n ratio. This method proves effective during the data pro-cessing in practice.