数字相敏检波器在测井仪器中的应用研究

A study on the application of the digital phase sensitive detection in the well logging tools

在测井仪器的信号采集设计中,需解决在恶劣工作环境中对微弱信号的精确测量的问题。常规的相关检测一般都采用模拟开关相敏检波来实现。然而硬件的相关检测方法,受到元器件温度性能的影响,表现为在高温情况下存在严重的测量误差。文章针对于目前测井仪器中的模拟相敏检波器的存在的稳定性低的缺点,提出了采用数字相敏检波器实现相关检测的的方法。该方法克服了温度变化所产生的影响,能够更精确的进行小信号的相关检测,最后使用MATLAB对文中的数字相敏检波算法进行了仿真验证。

When designing the signal acquisition of the well logging tools,we must think over the measures called correlation detection,which is used to detect the feeble desired signals exposed in a hostile environment full of noises.Conventionally,the analog switches in the phase sensitive detection module is most often adopted to implement the correlation detection.However,the effect of the high temperature on the performance of the components and parts such as analog switch usually results in measure error.Therefore,it is suggested in this paper to adopt digital phase sensitive detection instead of analog one to carry out correlation detection in order to overcome the limitation of the conventional analog phase sensitive detection.The method introduced in the paper is suitable for acquiring the feeble signals with little effects of high temperature and getting more accurate measurement than conventional one.In addition,by using the MATLAB software,the paper presents an emulation result to verify the application of equivalent sampling method and the digital phase sensitive detection.