A Self-Synchronizing Receiver for Transient Electromagnetic Systems

Transient electromagnetics is an efficient technique for acquiring subsurface resistivity, and its system mainly consists of a transmitter that induces eddy currents in the ground and a receiver that detects the resulting induced magnetic field subsequently. The strict time synchronization between the transmitter and receiver constrains the interoperability within different systems. To address this compatibility barrier, this paper proposes a universal self-synchronizing receiver with the ability to trigger itself by utilizing a high-frequency current sensor to directly capture the transmitting waveform. Through a peak detector with an adaptive threshold, the system accurately resolves the termination of transmitting current and triggers the acquisition of induced magnetic signal in the subsurface. Field experiments demonstrate that data acquired by the proposed receiver exhibits high consistency with the data collected by its own receiver in a commercial instrument, validating the effectiveness and practical value of this scheme in achieving cross-brand compatibility. This approach consequently overcomes the limitations that a transmitter can only be used together with its own receiver in TEM measurement, which is beneficial to interoperate between different systems and expand receiver channels in two or three-dimension scenarios.