A method of analyzing the characteristics of a power source includes receiving a power source having at least one phase and sensing voltage signals of each phase of the at least one phase. The method includes detecting a zero crossing event of a selected phase of the at least one phase based on the sensed voltage signals of the selected phase. The method also includes determining, using a processor, voltage information for each phase of the at least one phase based on the corresponding sensed voltage signals. The method further includes outputting a series of pulses via a galvanic isolator in response to the zero crossing event. Respective lengths of some or all of the pulses in the series are based on the corresponding voltage information for each of the at least one phase.