PURPOSE: To attain accurate tracking control without lowering the recording density in recording/reproducing a disc having a guide track by inverting the polarity of a tracking servo at a peak of a tracking error signal.
CONSTITUTION: A reflected light of a disc is photoelectrically converted by a 2- split PINFD1 and the outputs of differential amplifiers 2, 12 become the tracking error signal (c) where the polarity is inverted. In moving a spot from a projected part to a recessed part of the disc, a microcomputer 11 turns off a tracking group switch 5, applies a signal (a) to a drive circuit 7 via an FF16 and a jump pulse generator 10 so as to jump the spot. The peak of the signal (c) is detected by a peak detector 15, an output (d) is fed to a changeover switch 13, where the polarity of the signal (c) is inverted, the output (d) is fed to the FF16 so as to apply a deceleration signal (f) of spot movement to an adder circuit 6. A stable point (g) of tracking control is detected from the signal (c) and the deflection angle of the tracking mirror is controlled so as to make the signal (c) zero by turning the switch 5 on.
TAKAYAMA CHIHARU
OKU MASUO
SUZUKI MOTOYUKI
HITACHI VIDEO ENG