Abstract: In order to improve the sensitivity of the airborne transient electromagnetic signal, an implementation method of suppressing the coil motion noise and controlling the gain of the secondary field was proposed. Based on field programmable gate array (FPGA), the module of generating control signals was designed. On this basis, the circuit of signal conditioning was designed. Comparing with the preset threshold voltage, the motion noise was identified and removed, and the timing control was used to amplify the secondary field. The results show that the device can zero the baseline of the received signal waveform, and effectively increase the secondary field gain.