| 摘要 |
PURPOSE:To retrieve quickly and accurately a target track on a disk by stopping the movement of a pickup with a drive means when the coincidence is obtained between the value of comparison between an address detecting circuit and a memory means and the count value of a counter. CONSTITUTION:Address values (1-1,000) are provided from the most outer side to the most inner side of each track 1a of an optical disk 1. The address value (500) of a track to be retrieved is set to an address register 6 in the form of a binary signal. A comparator 7 subtracts the value of an address detecting circuit 4 from the value of the register 6. Then a binary signal of (300) is set to a track counter 8, and the counter 8 delivers its contents to a D/A converter 9. The converter 9 converts the binary signal of (300) into an analog signal and controls a motor driving circuit 10 to start the drive of a linear motor 3. Thus a pickup 2 is shifted at a high speed toward a track to be retrieved, i.e., to the inside of the disk 1. |
