TRACKING ERROR SIGNAL DETECTING METHOD AND APPARATUS THEREOF

摘要

PURPOSE: A tracking error signal detecting method and an apparatus thereof are to correspond an asymmetry of a pit occurred in a manufactured progress of a disk or an asymmetry occurred by a size of an optical spot and a mismatch of the pit. CONSTITUTION: A tracking error signal detecting apparatus comprises: a first and a second adders(12,14) for generating a straight line adding signal according to an optical detecting signal of a four dividing optical detector(10); a first and a second differential circuits(50,52) for differentiating the straight line adding signals on a time axis; a first and a second level comparators(20,22) for comparing the differentiated straight line adding signals with a certain reference level to generate a shaped pulse series; a phase difference detector(24) for generating a phase difference pulse series; and a low pass filters(26,28) for performing a low pass filtering of the output of the phase difference detector(24) to generating a tracking error signal. The tracking error signal is accurately occurred when occurring the asymmetry of a recording signal.