| 摘要 |
PURPOSE:To prohibit operation when there is no need for applying a stylus force and to prevent scoring on a disc surface by using a tracking servo on-off signal, and applying no stylus force when a tracking servo is not applied. CONSTITUTION:A tracking servo on-off signal supplied from a central control device 10 to a tracking servo circuit 9 is applied through a delay circuit 8 to one input terminal of an AND gate 7 and a detection pulse is applied from a circuit 6 for detecting the level of an FM input signal on the other input terminal. The circuit 8 corrects the deviation between the servo on-off signal and the time until the tracking operation is actually started. Even if the detection pulse is emitted from the circuit 6 while the servo operation is disturbed right after descending of a stylus on a disc surface in the stage of starting a play, the gate 7 is held closed and a switching transistor 4 is cut off, so that no current flows to a coil 2 for applying a stylus force and the operation for applying the stylus force is not accomplished. |
