| 摘要 |
PURPOSE:To reproduce a selected music securely even if an error exists between put-on position of a stylus tip and a soundless groove detection position, by providing a level detecting circuit and controlling a muting element on the basis of its detection output. CONSTITUTION:The level detecting circuit 17 has a comparator 17 which makes an output level comparison between a soundless groove and a sounding groove and generates no output when a sounding groove signal is obtained. When a music selection switch 5 is pressed, a soundless groove detector 1 detect the soundless groove 13 at the beginning of a piece of music. When a stylus 9 is lowered at a point Y in the sounding groove 12, an unselected music is detected. Its signal, however, is inputted (zero potential) to an AND gate 18 through the level detecting circuit 17. At this time, a positive voltage is applied from an arm up/down switch 20, but an FF19 is left reset and no playback signal is outputted. When the stylus 9 moves to the soundless groove, on the other hand, a positive voltage is applied from a circuit to the NAD gate 18. On the other hand, a positive voltage is further inputted from the switch 20 to turn on an FF14 and the playback signal appears at a terminal 15. When the stylus 19 is lowered at the soundless groove, it operates only instantaneously through a delay circuit 21 and then performs said operation thereafter. |
