A user navigational apparatus. The user navigational apparatus includes a
dial, a coding element, and an encoder. The coding element is coupled to
a dial. The coding element includes a track of alternating reflective and
non-reflective sections, each having a substantially oblique leading edge
relative to a direction of movement of the coding element. The encoder
includes an emitter and a detector. The emitter generates a light signal
incident on the track of the coding element. The detector detects a
reflected light signal which corresponds to a portion of the incident
light signal that is reflected off of the reflective sections of the
track. The detector also generates a channel signal corresponding to the
reflected light signal.