| 摘要 |
PURPOSE:To attain the elimination of offset of an optical disc device by controlling the count of a counter of a positioner control system in response to the amplitude of a feedback signal for tracking actuator. CONSTITUTION:An actuator current signal (c) to control tracking by feedback- controlling of the tracking actuator 18 through an LPF16 and a tracking power amplifier 17 so as to change an optical axis of a head 5 is applied also to a positioner processing circuit 21 of the control system of the positioner 6. When this signal (c) reaches a reference value or over, a counter of the circuit 21 is counted up or down in response to a two-phase position signal or an inverted two-phase position signal from a two-phase position signal generator 20 and an offset is added to a position feedback control signal (f). As a result, the offset by the eccentricity between the track center and the rotating center of the optical disc is eliminated substantially, allowing to apply accurate tracking to the track of the desired position. |
