| 摘要 |
PURPOSE:To facilitate an automatic adjustment of the fall position of a stylus tip by forming plural concentric modulated grooves in a record disk, and using the record disk recorded the signals of different frequency in those grooves. CONSTITUTION:The signals of different frequency are recorded in the plural concentric modulated grooves 2b-2d of the record disk 1 successively from the outer circumference. The stylus tip falls in the modulated groove to reproduce the signal of specific frequency. At this time, the signal of specific frequency is reproduced continuously. The fall position of the stylus tip is recognized from the frequency. Further, some specific relation is born between the displacement DELTAr of the fall point of the stylus tip from a specified position and the deviation DELTAf of the recorded frequency of the modulated groove at the stylus tip fall position from the specified position, and further specific relation is given between DELTAr and the angle DELTAtheta of rotation of a knob for stylus tip fall position adjustment; and the knob for adjustment is rotated by a necessary angle according to the frequency of the signal reproduced from the modulated groove where the stylus tip falls, thus making a position adjustment accurately. |
