Patent ID: 6233207
Filing Date: 2001-05-15
Classification: G11B

Abstract:
A polarity switching signal generator for generating a polarity switching signal for use in switching a polarity of a tracking error signal in accordance with a switching position between a land and groove during tracking servo control of an optical disk in which lands and grooves are alternately arranged in a radical direction, comprising:a rotational angle generating means for generating a rotational angle of said optical disk on the basis of a rotation signal based on rotation of said optical disk input from a driving means for driving the rotation of said optical disk;a switching position detecting means for detecting a switching position between a land and groove on the basis of an address signal read from said optical disk;a rotational angle determining means for determining said rotational angle generated by said rotational angle generating means at a timing in accordance with the detection of the switching position between a land and groove;a reference value storing means for storing a reference value to be compared with said rotational angle generated by said rotational angle generating means;a reference value setting means for updating the reference value stored in said reference value storing means with the rotational angle determined by said rotational angle determining means when said address signal is correct; anda comparing means for generating a polarity switching signal instructing the inversion of the polarity of the tracking error signal when the rotational angle generated by said rotational angle generating means matches with the reference value stored in said reference value storing means.