Patent ID: 6556521
Filing Date: 2003-04-29
Classification: G11B

Abstract:
An apparatus for recording data on and/or reproducing data from a disk in which a recording area is divided into sectors, each sector has a header for indicating an address, each header has a first header and a second header which are recorded to deviate from a center of a track in opposite directions, and the first header and the second header have address areas in which address signals of the sectors are recorded and synchronous signal areas in which synchronous signals for detecting the address signals recorded in the address area are recorded, the apparatus comprising:a reproducing signal generator, including a photodetector having radial pairs of detecting elements, which generates a reproducing signal including sum signals V1 and V2 of the radial pairs of detecting elements, a sum signal RF_sum of the detecting elements, and a push-pull signal RF_pp of the detecting elements, from an optical signal reflected from the disk; a header area detector which generates a header area signal comprising a header area from the reproducing signal received from the reproducing signal generator; a first synchronous signal level detector which receives the reproducing signal from the reproducing signal generator and detects a first magnitude Ivfo1 of a first synchronous signal in the first header by being synchronized with the header area signal received from the header area detector; a second synchronous signal level detector which receives the reproducing signal from the reproducing signal generator and detects a second magnitude Ivfo3 of a second synchronous signal in the second header by being synchronized with the header area signal received from the header area detector; and a balance calculator which calculates a balance value K1, of the magnitude Ivfo1 of the first synchronous signal detected by the first synchronous signal level detector and the magnitude Ivfo3 of the second synchronous signal detected by the second synchronous signal level detector.