Patent ID: 6345020
Filing Date: 2002-02-05
Classification: G11B

Abstract:
An apparatus for generating a tracking error signal using first through fourth elements A, B, C, D, respectively, of an optical detector which detects light beams reflected from an optical disk, comprising:a first adder to generate a first added signal (A+C) by adding first and third optical detection signals A and C output by the first and third elements, respectively; a second adder to generate a second added signal (B+D) by adding second and fourth optical detection signals B and D output by the second and fourth elements, respectively; a multiplexer to receive the optical detection signals A, B, C and D, the first added signal (A+C), and the second added signal (B+D), and to select and output a first group of the first and second added signals (A+C) and (B+D), a second group of the optical detection signals A and B, or a third group of the optical detection signals C and D; a phase detector to determine a difference between the signals of the first, second or third group output by the multiplexer, and output the difference as a tracking error signal and determine whether the tracking error signal is normal; and a selection controller to control selection of the first, second or third group by the multiplexer according to the determination of the normality of the tracking error signal by the phase detector.