| 摘要 |
PURPOSE:To read at a high SN ratio by analyzing a signal beam by a frequency analysis circuit, operating an output value with an arithmetic circuit at every frequency and detecting the frequency recorded on a recording medium. CONSTITUTION:A linear light beam exits from a light emitting diode 1, after the beam is reflected by a beam splitter 2, the image is formed on the recording surface of an optical disk 10 by an objective lens 3. The light beam projecting and forming the image forms the image on the recording surface of the disk 100 in such manner as receiving the change in reflectance. The light beam is incident on a servo detector 8 through the lens 3, the splitter 2 and a parallel plate 4 and detected as a focus servo and a tracking servo control signals. Based on the signals, by correcting an error of a focal and a track positions, read is operated. On the other hand, distribution of a frequency on a detecting part 5 is inspected by the frequency analysis circuit 6 and an arithmetic circuit 7. Thus, a recorded frequency on the disk 100, that is, the length of a pit is detected and the independent signals of respective recording tracks are outputted from the circuit 7. |
