| 摘要 |
PURPOSE: To discriminate the kind of a disk aunomatically. CONSTITUTION: Detected signals SA1-SF1 outputted from the optical pickup (not shown in the figure) of a disk player are synthesized and amplified in a broad-band amplifier 91. The output is converted into the DC by an envelope detector 92. The output of the envelope detector 92 is compared with a reference level in a level comparator 93, and the 'high' and 'low' pulses are formed. Then, in a track-pitch detector 94, the moving distance per unit time of the optical pickup moving at a constant speed is divided by the number of the 'highs' per unit time. Thus, the track pitch or the disk is computed. In a disk- kind discriminating device 95, the kind of the disk is discriminated based on the computed track pitch. That is, when the track pitch is, e.g. 1.2μm, it is judged that this disk is CD, and when the track pitch is 0.6μm, it is judged that the disk is DVD.
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