| 摘要 |
PURPOSE: A disk player having a double speed function is provided to allow a spindle motor servo circuit, related to the generation of signals controlling a spindle motor, and a phase control circuit to selectively control signals correspondingly to designated disk driving speeds, so that a single speed or a double speed can be enabled. CONSTITUTION: In a spindle motor servo circuit, the first phase comparison unit(31) compares the phases between a reference signal and an input signal when a disk player is operated in a single speed, and outputs the compared result as a pulse width modulation signal. A driving voltage generation unit(32) low-filters the pulse width modulation signal to a gain corresponding to the speed of the disk player, and generates the filtered result as a driving voltage. A disk driving unit(33) drives the disk player in a speed corresponding to the driving voltage. A synchronizing signal division unit(34) divides a synchronizing signal read from the disk at a division rate corresponding to the speed, and outputs the divided result as the input signal. In a phase control circuit, an EFM(Eight to Fourteen Modulation) signal control unit divides an EFM signal read from the disk at a division rate corresponding to the speed, for outputting. The second phase comparison unit compares the phase of a signal outputted from the EFM signal control unit and an oscillating signal. The second low filter low-filters a signal outputted from the second phase comparison unit. A gain control unit controls the low-filtered signal to a gain corresponding to the speed. A voltage control oscillator generates a signal having a frequency corresponding to the voltage supplied from the gain control unit. And a frequency conversion unit divides a signal outputted from the voltage control oscillator at a division rate corresponding to the speed, for outputting.
|
