| 摘要 |
PURPOSE:To surely make numerous track jumping operations by using a tracking means, by holding a tracking signal just before the tracking means makes a jumping operation, and controlling a shifting means during the jumping operation on the basis of the tracking signal. CONSTITUTION:A jump indicating signal 21 is inputted into an element 29 and slicing circuit 31. The output 30' of a monostable multivibrator 29 closes a switch 54 at the timing of a jumping operation and, at the same time, opens another switch 53 as a switch controlling signal 30. The output of the slicing circuit 31 is fed to a sample holding circuit 24 as a sample indicating signal 32 and the switch controlling signal 30' is used for hold indication. The hold starting timing is set to almost the same timing as that of generation of the jump indicating signal 21 and the hold ending timing is set to almost the same timing as the jump ending timing or about 1/3 of the time required for making the jump. When such constitution is used, a carriage 6 quickly follows the jump of an objective 9. |
