过套管电阻率测井仪信号调理电路的设计

Design of Signal Conditioning Circuits for Cased-hole Resistivity Logging Tool

超低频、纳伏级信号的检测,以及强干扰的抑制是过套管地层电阻率测井需要解决的关键问题。根据待测信号的特点,选用超低噪声、低漂移元器件,设计了相应的信号调理电路。测试结果表明,调理电路能有效抑制干扰信号、准确提取有用信号、实现了50 nV信号的可靠测量。

As far as cased-hole formation resistivity logging,the key problems needed to be solved are detection of ultra-low frequency and extremely weak signals,as well as reduction of strong interferences.Based on the features of signals to be measured,the corresponding signal conditioning circuits are designed with the components of ultra-low noise and low distortion.Experimental results demonstrate that the signal conditioning circuits can reduce interference signals effectively,extract useful signals accurately and realize the reliable measurement of 50 nV signal.