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US 6,747,924 B1Granted
Optical disk reproduction apparatus
AssigneeYamaha Corporation
InventorAkihiro Muramatsu
Life of this patent
Estimating the term…
Abstract
Prior to actual reproduction of an optical disk, test reproduction is performed with respect to a plurality of testing radial locations of the optical disk. In the test reproduction, waveform-equalization-characteristic parameters of the waveform equalization section are adjusted to optimal settings so as to optimize jitter of a reproduced RF signal detected at each of the testing radial locations of the optical disk. In the actual reproduction of the optical disk, the waveform-equalization-characteristic parameters of the waveform equalization section are adjusted to optimal settings that are predicted, from the optimal settings determined by the test reproduction, in accordance with a radial position or address, on the optical disk, of each location to be reproduced.
Claims10
An optical disk reproduction apparatus comprising:
- an optical pickup arranged to read out recorded information from an optical disk;
- a waveform equalization section arranged to perform a waveform equalization process on a reproduced RF signal that is generated on the basis of the recorded information read out by said optical pickup;
- a jitter detection section arranged to detect jitter of the reproduced RF signal having been subjected to the waveform equalization process;
- a storing section arranged to store waveform equalization characteristics of the waveform equalization section;
- and
- a control section arranged to:
- perform test reproductions on the optical disk at a plurality of radial locations of the optical disk prior to actual reproduction of the optical disk;
- adjust a waveform equalization characteristic of said waveform equalization section to minimize jitter of the reproduced RF signal detected by said jitter detection section at each of the radial locations of the optical disk;
- store the waveform equalization characteristics adjusted at the each of the radial locations of the optical disk;
- and
- during the actual reproduction of the optical disk, adjust the waveform equalization characteristic of said waveform equalization section to a setting that is predicted on the stored waveform equalization characteristics and in accordance with a radial position on the optical disk, at each location to be reproduced via said optical pickup.
8 more elements
An optical disk reproduction apparatus comprising:
- a rotation control arranged to drive, at a constant angular velocity, an optical disk having information recorded thereon at a constant linear velocity;
- an optical pickup arranged to read out recorded information from the optical disk;
- a waveform equalization section arranged to perform a waveform equalization process on a reproduced RF signal that is generated on the basis of the recorded information read out by said optical pickup;
- a jitter detection section arranged to detect jitter of the reproduced RF signal having been subjected to the waveform equalization process;
- a storing section arranged to store waveform equalization characteristics of the waveform equalization section;
- and
- a control section arranged to:
- perform a test reproduction on the optical disk at a single radial location of the optical disk prior to actual reproduction of the optical disk;
- adjust a waveform equalization characteristic of said waveform equalization section to minimize jitter of the reproduced RF signal detected by said jitter detection section at the radial location;
- store the waveform equalization characteristic adjusted at the radial location of the optical disk;
- and
- during the actual reproduction of the optical disk, adjust the waveform equalization characteristic of said waveform equalization section to a setting that is predicted on the stored waveform equalization characteristic and on the basis of variation of linear velocity in accordance with a radial position on the optical disk, at each location to be reproduced via said optical pickup.
9 more elements
An optical disk reproduction apparatus comprising:
- an optical pickup arranged to read out recorded information from an optical disk;
- a waveform equalization section arranged to perform a waveform equalization process on a reproduced RF signal that is generated on the basis of the recorded information read out by said optical pickup;
- a demodulation section arranged to demodulate the reproduced RF signal having been subjected to the waveform equalization process, while cumulatively storing the reproduced RF signal into a buffer memory;
- a jitter detection section arranged to detect jitter of the reproduced RF signal having been subjected to the waveform equalization process;
- a focus servo control section arranged to perform focus servo control by detecting a focus error on the basis of two focus-error-detecting signals that are generated on the basis of the recorded information read out by said optical pickup;
- a focus adjustment section arranged to perform a focus adjustment process for adjusting either one or both of a focus balance and focus offset by use of the two focus-error-detecting signals;
- a low-frequency-component detection section arranged to detect a low-frequency component in a focus drive signal produced by said focus servo control section;
- and
- a control section arranged to perform control to:
- when it is determined that the low-frequency component in the focus drive signal has exceeded a predetermined threshold value or a difference in the low-frequency component in the focus drive signal between an innermost location and a reproduced location of the optical disk has exceeded a predetermined threshold value and/or the jitter of the reproduced RF signal has exceeded a predetermined threshold value and also on condition that more than a predetermined quantity of data are currently being stored in said buffer memory, suspend readout operation of said optical pickup and adjust said focus adjustment section so as to optimize the jitter of the reproduced RF signal detected by said jitter reproduction section;
- and
- resume the readout operation of said optical pickup after adjustment to said focus adjustment section.
9 more elements
Dependencies are inferred from the claim text.