POSITION DETECTING APPARATUS

摘要

A device (18) is described for detecting the position of the head (17) of an optical disc player. Light is emitted on a scale moving with the head and is converted to an analog signal by a photosensor whose width is half the pitch of the scale graduation. The signal is A/D-converted (21), and the multi-level digital data are added to or subtracted from an address register, depending on the moving direction of the head.