To improve the detection precision of the transient electromagnetic method, dense observation points and windows are necessary. However, to keep the number of samples in every acquisition window unchanged, the sampling rate of principal transient electromagnetic instruments decreases with transmitter frequency, and the increased windows reduce the original signal-to-noise ratio at the cost of decreasing the number of samples participating in the statistical average. Taking the V8 receiver from Phoenix Geophysics as an example, this study analyzes the main steps in the signal detection of a transient electromagnetic instrument. Following the Wiener-Khinchin law of large numbers, herein, a fixed, high-sampling-rate receiver scheme, which does not decrease the number of samples participating in the statistical average while increasing the windows, is proposed. Starting from the Nyquist sampling theorem, we provide the definition of detection precision with the dimension of length. Then, according to the necessary conditions for reconstructing a geoelectric structure, we determine the relationship between a survey grid space and a detection depth space corresponding to window interval as well as the minimum period in a geoelectric signal spectrum. The exploration of the multilayer, water-filled goaf of the Dazigou Coal Mine in Datong shows the aliasing caused by undersampling and the fine geoelectric section obtained using additional conditions under a geophysical premise. The necessary conditions for the reconstruction of the geoelectric structure indicate that satisfying the Nyquist sampling theorem may be insufficient in reconstructing the geoelectric structure, but the structure must not be reconstructed completely without not satisfying this theorem.

为提高瞬变电磁法的检测精度，需要密集的观测点和窗口。然而，为了保持每个采集窗口的样本数不变，主要瞬态电磁仪器的采样率随发射频率的增加而降低，增加的窗口以减少参与的样本数为代价降低了原始信噪比在统计平均值中。本研究以凤凰地球V8接收机为例，分析了瞬变电磁仪信号检测的主要步骤。遵循Wiener-Khinchin大数定律，本文采用固定的高采样率接收方案，在增加窗口的同时不减少参与统计平均的样本数，被提议。从奈奎斯特采样定理出发，我们以长度为维度给出了检测精度的定义。然后，根据重构地电结构的必要条件，确定窗距对应的勘测网格空间与探测深度空间的关系以及地电信号谱中的最小周期。对大同大子沟煤矿多层充水采空区的勘探，显示了欠采样造成的混叠和地球物理前提下附加条件得到的精细地电剖面。地电结构重构的必要条件表明，满足奈奎斯特采样定理可能不足以重构地电结构，