| 摘要 |
PURPOSE:To realize the searching without reducing the relative speed between a spot and a track, by carrying out the scanning control while giving a periodic change to the relative speed between a pickup and recording track toward the radius of a disk. CONSTITUTION:The light irradiated from the right is reflected by a tracking mirror 3 to be changed into a spot 6 on a disk 1. The mirror 3 is rocked in the A-B direction by a driving means 4. The reflected light is returned with a change of its volume received according to the presence or absence of the bit in the spot 6 to be focused on a photoelectric transducer 8. The reproduced signal turned into an electric signal by the transducer 8 is amplified 9, and the cutoff frequency is applied to an HPF10 of f1 as well as to an HPF13 of f2. The signal passed through an HPF10 is turned into a binary signal by a comparator 11 to be supplied to a demodulating circuit 12. While the signal passed through the HPF13 is applied to a clock extracting circuit 14, and the produced and demodulated clock is supplied to the circuit 12 to be demodulated. In such way, the reading of address information is possible in the searching time. |
