An electrical circuit and a procedure for tracking at least one input pulse width applied to the electrical circuit. The electrical circuit includes a threshold component (e.g., a comparator) arranged to provide an output pulse width based on whether an input to the threshold component exceeds a threshold. The circuit also includes a controller arranged to control the threshold of the threshold component, based on the at least one input pulse width applied to the electrical circuit, such that the output pulse width of the threshold component tracks the at least one input pulse width applied to the electrical circuit. The controller includes at least a switch, and the output pulse width tracks the at least one input pulse width by following or anticipating the pulse width. In one example embodiment the tracking is performed for a series of pulses of varied widths.