TRACKING SERVO APPARATUS OF OPTICAL DISK PLAYER

摘要

PURPOSE: A tracking apparatus of an optical disk player is provided to obtain tracking error signal by using the difference of sum signals detected from the synchronizing signal domain of a header. CONSTITUTION: A light detector(50) having four light receiving elements(A-D) divided in the tangential and radial directions is installed on an optical head(40). A sum signal detector(42) detects a sum signal of electrical signals generated from the light receiving elements(A-D). A tracking error signal generation unit comprising an envelope detection unit(44a), an A/D converter(44b), a tracking error signal generator(44c) and an average value operation unit(44d) generates a tracking error signal, supplied to a tracking actuator, by an average of tracking error signals obtained from adjacent sectors. A difference signal detector(46) detects a difference signal of the electrical signals generated from the light receiving elements(A-D). A synchronizing signal domain detection unit(48) composed of a wobble detection unit(48a), a wobble PLL(48b), a header section detection unit(48c) and a synchronizing signal domain detector generates a section signal to discriminate a synchronizing signal domain from the difference signal generated from the difference signal detector(46).