REPRODUCING DEVICE OF DISCOIDAL RECORD CARRIER

PURPOSE:To set exact target position and enable retreaval operation at high speed and at high accuracy by obtaining accurate linear velocity at the start of information signal on the disk. CONSTITUTION:When a disk rotates and reproduced signal is picked up, a periodic signal extracting circuit 2 operates to extract the periodic signal. When phase difference between the periodic signal and internal reference periodic signal becomes a fixed value and does not change further, the disk rotates correctly. Under this condition, an information signal reproducing section is moved radially on the disk, and arrives at radius Rs of an information signal start 14. A detector 7 for number of revolutions of a disk is provided in a disk motor 6, and detected pulse is inputted to a linear velocity detecting circuit 8, and the output is recorded in a memory circuit 9. When an information signal start detecting circuit starts giving instruction, that is, at radius Rs, a calculating section 11 for retreaval performs operation to find out retreaval position using correct linear velocity A stored in the circuit 9.