Disk data reproducing method and apparatus for reading data at arbitrary

Abstract

In the operation to access data on a disk, the data reading operation is enabled before the rotary speed of the spindle motor of the disk is completely regulated to thereby minimize the access time and power consumption of the spindle motor for acceleration or deceleration thereof. When the actuator is in the access operation, the motor is compulsorily driven. From a time when the actuator reaches a target track in the access operation to a time when the rotary speed of the motor becomes equal to a predetermined rotary speed, the frequency control signal is created according to the position of the actuator and the rotary speed of the spindle motor. After the data reading operation is commenced, to fixedly set the data transfer rate to a predetermined value, the variable reference clock signal is stepwise corrected to be equal to the fixed master clock signal in a frequency range calculated according to the motor rotating speed and the capture range. Therefore, the synchronization can be established in a frequency range remarkably exceeding the capture range of the phase-locked loop circuit, which makes it possible to dispense with the wait time conventionally required in the access operation before the motor rotating speed reaches a fixed linear speed for data reproduction.