| 摘要 |
PURPOSE:To attain the address retrieval at a high speed by having a rough retrieval after deciding the position of a retrieving address from the address pitch and the head address position which are calculated from the address information and the positions of two adjacent points of the radius direction stored in a memory. CONSTITUTION:Position information L1 and L2 on two points of addresses T1 and T2 on the radius of a disk 10 are detected via a potentiometer 7. A CPU2 performs an operation from equations I and II to decide the pitch information P and the head address position information LO to store them in a memory 1. An operation is performed from the contents of the memory 1 and the equation II, and the CPU2 decides the position information L corresponding to a retrieving address T. Then a linear motor, etc. are controlled, and the rough retrieval is performed by a pickup 9 at a speed higher than the address read-out limit speed. Then the fine address retrieval is performed based on the address information via a kick pulse generating part 5 which works in response to the CPU2. In such a way, the address retrieval is possible at a high speed. |
