| 摘要 |
PURPOSE:To obtain an optical disc recording and reproducing device superior in mass productivity and compatibility between devices by controlling the rotative angular velocity of a motor, which rotates a recording disc, in accordance with the eccentric state to a relax the mechanical precision. CONSTITUTION:The direction and the extent of eccentricity of a recording disc 1 are stored in a control circuit 13 as the coefficient of each angular section in each radius. When information is recorded, the address where information should be written on the recroding disc 1 is set to a write address setting circuir 12, and a motor 7 transports an optical pickup device 5 to a position corresponding to this address, and the control circuit 13 reads the radius of said position from the write address setting circuit 12. The control circuit 13 receives a timing pulse (b) and a pulse (a), which is generated once for one rotation of the recording disc 1, and uses the coefficient of the corresponding angular section and the radius to operate an angular velocity and sets a frequency division ratio N of a programmable frequency divider 9 to this value. An amplifier 11 supplies a current to a motor 3 in accordance with the output signal of a phase comparator 10, and finally, the motor 3 is rotated in the angular velocity corresponding to a frequency f0/N. |
