Subsurface resistivity measurements using square waveforms

This work analyzes the effect of inductive and capacitive coupling from the injecting circuit to the detecting circuit in resistive field surveys. Experimental results demonstrate that if a square waveform is injected into the soil and synchronous sampling is used to sample the flat zone of the detected voltage, then the interference is greatly reduced. Furthermore, square waveforms are easier to generate than sinusoidal waveforms, so that they offer a new approach to subsurface resistivity measurements.