| 摘要 |
PURPOSE:To enable to retrieve the reproduced linear speeds of discs having different linear speeds by providing reference freqeuncy generating means for sweeping an output frequency, thereby sweeping the rotating speed of a motor. CONSTITUTION:A clock signal which includes rotating speed information is extracted by clock extracting means from the output of pickup means 2, the clock signal is inputted to the first speed controlling means 11, thereby detecting the phase difference from the reference signal and controlling the rotating speed of the disc 1 with the phase error output. The position of the disc 1 of the means 2 to the radial direction is detected by position detecting means 5, thereby varying by frequency varying means 7 the output frequency of reference frequency generating means 6, and the output is inputted to the second speed controlling means 8, thereby controlling the rotating speed of the disc 1. Either one of the means 8, 11 is selected by switching means 9, thereby controlling driving means 4. |
