| 摘要 |
PURPOSE:To remove jitter at the time of recording by controlling not only a spindle motor but also a clock at the time of recording when the jitter synchronizing with a rotating cycle is caused. CONSTITUTION:An ATIP carrier is fetched from an optical disk 10 by a signal separation circuit 16 and compared with the signal of the frequency divider of a rotation control system for controlling the rotation of the spindle motor 13 by a phase comparator 17a, then the rotating speed of the motor 13 is controlled in accordance with a difference between them. Furthermore, the ATIP carrier signal and the signal of the frequency divider of a control system for controlling the clock of a CIRC encoder 21 are compared in terms of phase by a phase comparator 17b, and the oscillation frequency of an oscillator 19b is changed by voltage in accordance with the difference between them, then clock frequency is locked at a specified value when the difference is not found. By intentionally giving the jitter synchronizing with the jitter of the ATIP carrier signal at the time of recording to the write signal of the encoder 21, the jitter caused by eccentricity based on the error of mechanical accuracy at the time of chucking is removed. |
