A light beam is scanned on a track of a recording medium, the track having a first track region and a second track region, each track region having a physical property that has recurring deviations. A wobble signal is derived from the light beam, the wobble signal having information associated with the recurring deviations. Whether the light beam is at the first track region or the second track region is determined based on a frequency, a period, or a pulse width of the wobble signal.