| 摘要 |
PURPOSE:To facilitate the execution of appropriate jumping to a desired track, by controlling the tilt of a tracking mirror within a prescribed range at a place near the desired track. CONSTITUTION:A designated address A fed through a console 23 is then fed to a microcomputer 18. While the address B of the using track which is read out by an address signal discriminating circuit 17 is fed to the computer 18. Then a subtraction (A-B) is performed to give a rough retrieval to shift a light beam 2 to a track near the designated address. When the DC component of the tracking driving voltage is set within a prescribed voltage range, the jumping commands equivalent to the number of pieces of results of subtraction are delivered to a jumpting driving circuit 26 from the computer 18. Then the angle of a tracking mirrow 5 is varied to perform a fine retrieval to detect the desired address. In this case, the incident light beam 2 is approximately vertical to the surface of a disk 7 at the place near the desired track. This improves the envelope of a reproduced signal and stables the tracking. |
