| 摘要 |
PURPOSE:To reduce the influence of an error due to inclination of an object, by detecting a reflected ray from the object, reproducing an uneven recording signal, and after that, extracting a tracking error signal of only a bit part on the track. CONSTITUTION:An optical spot is formed on a disk 2, its reflected ray is inputted to a 2-split photodetector 24, and from its sum, an uneven signal is reproduced in an uneven signal reproducing part 51. On the other hand, a difference signal of the photodetector 24 is inputted to a tracking error signal extracting part 52, a tracking error signal of only a bit part from in its output signal is extracted by a bit part tracking signal extracting part 53 in accordance with a signal of a reproducing part 51, and by its signal, a tracking actuator 55 is controlled. Accordingly, a tracking error can be suppressed to the minimum by detecting a zero crossing point of the uneven signal, discriminating the bit part from the part having no bit, and removing a signal of the part having no bit. |
