Optical disc apparatus

Claim 1

An optical disc apparatus for use with an optical disc having a plurality of recording tracks each of which is provided at predetermined intervals with pairs of servo pattern areas and data areas, said servo pattern areas being recorded with a pair of wobble pits each disposed off the center of the recording track in opposite directions, a clock pit disposed on the center of the track, and an address pit pattern consisting of a plurality of pits each of which indicates a relative track address of the recording track by using a data pattern repeated in a predetermined cycle, said optical disc apparatus comprising: an optical pick-up device for recording data on, and/or regenerating data from, said optical disc; a relative address detection means for detecting a relative track address based on a regenerative signal from said optical pick-up device and for outputting detected relative address data; and an address/speed detection means for receiving said relative address data outputted by said relative address detection means, and detecting an absolute track number of the track which said optical pick-up device is accessing and a travel speed data of said optical pick-up device moving across the recording tracks, said address/speed detection means comprising a comparator for comparing said relative address data with a feed-back data from a residue detecting circuit and outputting an differential data, a digital data filtering means for filtering differential data and for outputting an integrator input data and a speed data, an integrator for adding up said input data to output an absolute address data, and a residue detection circuit for calculating the residue arising when the value of said absolute address data is divided by the number of said predetermined cycle of said relative address patterns and feeding its residue data back to said comparator.