A method of performing an electromagnetic measurement of an earth formation includes disposing a downhole tool in a borehole in an earth formation, the downhole tool including an electrically conductive component, at least one electromagnetic transmitter located at a location along the tool, a first receiver located a first distance from the location, and a second receiver located at a second distance from the location. The method also includes applying a single rectangular current pulse having a substantially constant amplitude to the transmitter to generate an electric current in the formation, the current pulse having a specified time duration ΔT. The method further includes measuring transient signals during a time period subsequent to the time in response to the generated current, combining the transient signals to generate a combined transient signal, and estimating a resistivity of the formation based on the combined transient signal.