JPS6423474A - Optical disk device - Google Patents

Abstract

PURPOSE:To simplify the constitution of a tracking control part by providing an electrical network for generating jumping disturbance, forming thence required three kinds of signals and giving them to a prescribed point of a servo loop. CONSTITUTION:When the tracking control part TSL is turned on by a switch SW to operate its tracking control, a signal JPEN is turned into L, and an output of a 3-state buffer TB is brought under floating condition, and then an adding electric potential voltage via a capacitor C1 from the network 1 for generating jumping disturbance to a adding node N2 between the switch SW and an actuator driving circuit D is turned into zero. On the other hand, at the time of jumping, the switch SW becomes off, and then the signal JPEN becomes H, while a signal JPP is H, and a positive electric potential voltage is impressed to the node N2, and after a light spot attains an accelerative level, the node N2 is impressed by zero electric potential voltage in the same manner and followed by a negative electric potential voltage for braking, to carry out a jumping operation. The reverse jumping is also in the same case, so that the tracking control circuit can be so simply constitute of only one set both for the adding node and for a control line.