ACCURATE TRACK-COUNT ACCESSING OF OPTICAL DISK DRIVE

In order to create a rapid accessing feature of optical disk drives, t he optical head should be positioned as accurately as possible near th e target track if seeking motion is desired. First, an accurate seekin g span decision algorithm employed to predict the spiral tracks' rotat ional number during seeking is discussed. Second, a method of correcti ng a miscount in the number of crossing tracks for accurate track-coun t accessing is proposed. During the seeking operation, the method of c orrecting the track miscount can generate a virtual track-crossing pul se in real time when a track-crossing pulse is missed due to a distort ed tracking error signal during seeking. These two methods are practic ally installed in a 130 mm International Organization for Standardizat ion (ISO) format optical disk drive and effectively operated for accur ate track-count accessing.