Jump test for CD recording groove

Abstract

In using an optical disc such as a digital versatile disc (DVD), if a track jump occurs, it is sometimes desirable to detect the track jump as soon as possible after it occurs. The optical disc format includes a pre-groove track structure which provides frames in which data can be written to or read from the disc. The structure of the pre-groove track is designed to detect the possible occurrence of an inadvertent track jump as quickly as possible and in a time shorter than that required to detect a track jump using only disc addressing data. The pre-groove track structure can be adjusted to enhance track jump detection, such as by position coding in the data line segment of the track, or a coding scheme for the period of addressing data dibits.

Description

technical field [0001] The invention relates to the field of track jump detection during reading and / or writing of optical discs. Background technique [0002] When reading and / or writing data using an optical disc data recorder drive, such as DVD+RW, there is a possibility of suffering from unintentional track jumps due to mechanical or other disturbances. Optical discs such as digital versatile discs (DVD) or compact discs (CD) are typically formatted with multiple tracks consisting of a single spiral groove, each track being considered a 360 degree rotation of the spiral. These tracks provide the frames for writing data on and reading data from the disc. To read data, for example, a read head is aligned with a desired track on the disc, and as the disc is rotated past the read head, the data on the track is read. A track jump can be viewed as the relative displacement of the read / write head away from the desired track. Track jumps occur as a corollary during the operat...

AI Technical Summary

Problems solved by technology

Because the timing and displacement from the desired track is not intentional, the disk drive control is unaware that the desired track alignment has been lost, and the control may not be able to determine what displacement occurred in order to correct or compensate for it

Images