Current borehole receivers only measure a single parameter of the magnetic field component, which does not meet the special requirements of controlled-source electromagnetic (CSEM) methods. This study proposes a borehole electromagnetic receiver that realizes synchronous acquisition of the vertical electric field component and three-axis orthogonal magnetic field components. Results of the experiments show that our system functioned adequately and that high-quality CSEM signals were obtained.

The existing current recorder is inadequate for continuous recording, precision, bandwidth, dynamic range, and input range. A new full waveform current recorder that is ideal for measuring current signal for electrical prospecting applications is presented. The full waveform current recorder is capable of measuring current with bandwidth from DC to 10 kHz, with a power spectrum density noise floor of 10 A/rt(Hz) at 10 Hz.

High-power transmitters have been playing a significant role in deep electromagnetic exploration. However, a high-power transmitter needs high-voltage support, which is a potential risk for researchers. According to the actual situation of field exploration, we designed a wireless monitoring system. The system offers two advantages, the first of which is high security; the second advantage is simple operation.

To assess the performance of the developed EM receivers, this paper presents a multifunctional waveform generator with three waveforms: 1) a wideband, low-noise electromagnetic field signal to be used for magnetotelluric, audio-magnetotelluric, and long-period magnetotelluric studies; 2) a repeating frequency sweep square waveform for CSAMT and SIP studies; and 3) a “positive-zero–negative-zero” signal that contains primary and secondary fields for time-domain-induced polarization studies.