Information recording disk, and information recording/reproducing method and apparatus utilizing the same

A method of recording information on and/or reproducing information from a disk having thereon a plurality of tracks arranged in a plurality of turns in one of a concentric and a spiral manner, each of said tracks being divided into a plurality of sectors each recording therein information of a predetermined number of bytes, and a plurality of servo signals for detecting tracking error, said servo signals being discretely recorded therein in each of said sectors at predetermined angular intervals and including first and second wobble pits formed in positions which mutually deviate from the center of a respective track in opposite directions, the number of said servo signals recorded in each sector being an integer and the integral number in an inner track being greater than that in an outer track, said method comprising steps of:

• rotating the disk at a constant angular velocity;
• detecting the tracking error on the basis of the servo signals, by utilizing a first reference clock signal having a constant frequency;
• and
• effecting recording of information on and/or reproducing of information from a desired track, by utilizing a second reference clock signal, and by controlling frequency of the second reference clock signal so as to be higher when the desired track is positioned on an outer side of the disk.

An apparatus for recording information on and/or reproducing information from a disk having thereon a plurality of tracks arranged in a plurality of turns in one of a concentric and a spiral manner, each of said tracks being divided into a plurality of sectors each recording therein information of a predetermined number of bytes, and a plurality of servo signals for detecting tracking error, said servo signals being discretely recorded therein in each of said sectors at predetermined angular intervals and including first and second wobble pits formed in positions which mutually deviate from the center of a respective track in opposite directions, the number of said servo signals recorded in each sector being an integer and the integral number in an inner track being greater than that in an outer track, said apparatus comprising:

• a motor for rotating the disk at a constant angular velocity;
• a first clock generating circuit for generating a first reference clock signal having a constant frequency on the basis of the servo signals recorded on a desired track of the disk;
• a second clock generating circuit for generating a second reference clock signal from the first reference clock signal, said second clock generating circuit comprising means for controlling the frequency of the second reference clock signal so as to be higher when the desired track is located on an outer side of the disk;
• an error detection circuit for detecting tracking error on the basis of the servo signals recorded on the desired track by utilizing the first reference clock signal;
• a head for effecting recording of information on and/or reproducing of information from the desired track, based on the second reference clock signal;
• and
• a control circuit for effecting the tracking control of said head, by utilizing the tracking error detected by said error detection circuit.