Optical disk recording and reproducing method and apparatus therefor

Abstract

An optical disk apparatus which can with high-speed access and low power consumption reproduce data recorded thereon at constant linear velocity and which, if used as a writable type, can record data by using CAV control and CLV control in combination, with much improved high-speed access and low power consumption. The optical disk apparatus comprises a reproduced signal detector which digitizes a reproduced signal from an optical disk, a broadband synchronizing clock signal generator for generating a synchronizing clock signal for use in reproducing data, a signal processor for processing signals, and a disk rotation controller for controlling the optical disk by switching control modes according to the reproducing position of the disk, that is, performing CAV control using the constant rotating velocity which is the same as the current rotating velocity in a range where the synchronizing clock signal generator allows a reproduced signal to be subjected to pull-in-synchronization, and performing CLV control so that the linear velocity is constant to minimize the pull-in-enable changes of number of revolutions in a range exceeding the pull-in-synchronization range, by which arrangement the amount of change of number of spindle motor revolutions when the reproducing position of the optical pickup changes is minimized, thus further reducing power consumption and access time.