Method and apparatus for measuring off-track detection sensitivity
AssigneePanasonic Corporation
InventorYasuo Nakata
Life of this patent
Estimating the term…
Abstract
An off-track duty measurement unit measures off-track detection sensitivity on the basis of an off-track signal, and track cross cycle information that is obtained from a tracking error signal measured by a track cross cycle measurement unit, whereby off-track detection sensitivity can be measured more accurately. Further, an off-track detection sensitivity controller changes the detection sensitivity of an off-track signal detector according to the obtained off-track detection sensitivity, whereby the off-track sensitivity can be kept constant for various kinds of discs, and accordingly, stabilities of off-track detection, track pull-in judgement, and track jumping can be secured.
Claims2
A signal processing device comprising:
- a track cross cycle measurement unit for receiving a tracking error signal showing a degree of deviation of a playback unit for playing data recorded on a recording medium from a track formed on the recording medium, and measuring a track cross cycle that is a cycle with which the playback unit crosses the track, on the basis of the tracking error signal;
- an off-track signal detector for detecting an off-track signal indicating that the playback unit is off the track;
- an off-track duty measurement unit outputting an off-track duty signal on the basis of the off-track signal;
- a tracking driver for moving the playback unit for playing the data recorded on the recording medium in the direction of the radius of the recording medium;
- a sled driver for moving the playback unit;
- a sled controller for controlling said sled driver;
- a system controller, said system controller controlling the tracking driver and the sled driver, and measuring the off-track detection sensitivity while moving or vibrating the playback unit in the direction in which the playback unit crosses the track;
- wherein said track cross cycle measurement unit gives the measured track cross cycle to the tracking driver and the sled controller.
A signal processing device comprising:
- a track cross cycle measurement unit for receiving a tracking error signal showing a degree of deviation of a playback unit for playing data recorded on a recording medium from a track formed on the recording medium, and measuring a track cross cycle that is a cycle with which the playback unit crosses the track, on the basis of the tracking error signal;
- an off-track signal detector for detecting an off-track signal indicating that the playback unit is off the track;
- an off-track duty measurement unit outputting an off-track duty signal on the basis of the off-track signal;
- a tracking driver for moving the playback unit for playing the data recorded on the recording medium in the direction of the radius of the recording medium;
- a sled driver for moving the playback unit;
- a sled controller for controlling said sled driver;
- a system controller, said system controller controlling the tracking driver and the sled driver, and measuring the off-track detection sensitivity while moving or vibrating the playback unit in the direction in which the playback unit crosses the track,
- wherein said system controller performs control so that the track cross cycle becomes a predetermined range;
- and
- wherein said track cross cycle measurement unit gives the measured track cross cycle to the tracking driver and the sled controller.
Dependencies are inferred from the claim text.