Patent ID: 6262861
Filing Date: 2001-07-17
Classification: G11B

Abstract:
A method of detecting a scanning position on a disk which is time-divisionally recorded with a data region and a servo region based on a signal read from the disk according to a phase demodulation technique, a servo mark pattern being recorded in three kinds of position regions EVEN1, ODD and EVEN2 in the servo region with a phase which changes by a fixed quantity for each successively scanned cylinder on the disk but in mutually opposite directions between the position region ODD and the position regions EVEN1 and EVEN2, said method comprising the steps of:(a) converting a phase of the servo mark pattern in the position regions EVEN1 and EVEN2 into a phase of the servo mark pattern at an approximate center of the position region ODD; and(b) detecting the scanning position on the disk based on the converted phase of the servo mark pattern in the position regions EVEN1 and EVEN2 and the phase of the servo mark pattern in the position region ODD.