摘要:
The device according to the invention is suitable for recording a rewritable information carrier such a CD-E covered by a phase-change recording layer. As is known, such an information carrier has a limited useful life because the recorded, optically readable patterns start deviating ever more from the desired form when recorded recurrently. The invention is also based on the recognition that this degradation is accelerated if a certain part of the track on the information carrier constantly accommnodates the same patterns, for example, if information blocks are recorded starting from fixed initial positions and the information is represented by the patterns in a specific manner. The device comprises means for shifting the initial position along the track over a distance randomly selected within predefined boundaries and/or for adapting the manner of representation. This causes constantly different patterns to be recorded, even if the same information is to be recorded in a specific part of the track. The information carrier described according to the invention has an additional margin between the information blocks to allow of the shifting of the initial position.
摘要:
The life of a rewritable information carrier such a CD-E covered by a phase-change recording layer is extended by varying the manner of representing information of an information block, for subsequent recordings, in the same portion of the record carrier. The manner can be changed, for example, by shifting the initial position at which representing information is written along the track over a distance randomly selected within predefined boundaries; or by writing a varying amount of information representing information from the end of the block before the start of information from the beginning of the information block to rotate the information in the track; or by scrambling the information in a varying manner such as using different keys. The manner of representation can be changed, for example, for each subsequent recording on the same portion of the record carrier. This causes different patterns to be recorded in the same portion, even if the same information is recorded in that portion of the track.
摘要:
A disc-shaped information carrier has a track thereon which follows a helical or concentric path forming successive windings. For identifying each winding the information carrier also has a servo pattern thereon which includes position-information as well as synchronization elements. Such elements may be, for example, brief pulses in a continuous track wobble, and are distinguishable in adjacent windings based on a predetermined detectable parameter, such as alternating polarity or shifted relative phase positions. During recording by a read/write head a system control detects the synchronization elements and monitors whether a deviation has occurred signifying that the read/write head has wandered to an adjacent winding. In that event recording is interrupted. Thus, the least possible information in adjacent windings is overwritten in the case of disturbances resulting from shocks or defects of the information carrier. A read device is also described which interrupts reading if the winding identification provided by the synchronization elements signifies erroneous operation.
摘要:
The invention relates to an optical disc for recording data at a constant density, so called CLV (Constant Linear Velocity) or at zoned CLV. The disc has headers distributed along the disc on regular angular positions, a so called CAV (Constant Angular Velocity) pattern subdividing the track in track portions for recording an amount of data proportional to the radial position of the track portion concerned. Address information included in the headers is provided at the data density, which is CLV. The apparatus comprises header detection means for detecting the headers at the CAV locations, and for recovering position information from the headers at CLV density. Data sectors do not start at headers and are not fitted regularly between the headers, but start and stop at arbitrary positions which are calculated from the known amounts of data recordable in the track portions.
摘要:
An optical record carrier has parallel tracks for recording user information in a pattern of optically detectable marks, the tracks being provided with control information. The tracks are grouped in pairs of neighboring tracks. The control information in both tracks of a pair is identical and the control information in tracks of different pairs is different. The identity of the control information reduces the effect of crosstalk on neighboring tracks.
摘要:
A disc-shaped information carrier and a device for reading and/or writing information blocks in a track thereon which follows a helical or concentric path forming successive windings. For identifying each winding the information carrier also has a servo pattern thereon which includes position-information as well as synchronization elements. Such elements may be, for example, brief pulses in a continuous track wobble, and are distinguishable in adjacent windings based on a predetermined detectable parameter, such as alternating polarity or shifted relative phase positions. The device has a read/write head and a system control which during writing detects the synchronization elements and monitors whether a deviation has occurred signifying that the read/write head has wandered to an adjacent winding. In that event writing is interrupted. Thus, the least possible information in adjacent windings is overwritten in the case of disturbances resulting from shocks or defects of the information carrier. A read device is also described which interrupts reading if the winding identification provided by the synchronization elements signifies erroneous operation.
摘要:
The invention relates to an optical disc for recording data at a constant density, so called CLV (Constant Linear Velocity) or at zoned CLV. The disc has headers distributed along the disc on regular angular positions, a so called CAV (Constant Angular Velocity) pattern subdividing the track in track portions for recording an amount of data proportional to the radical position of the track portion concerned. Address information included in the headers is provided at the data density, which is CLV. The apparatus comprises header detection means for detecting the headers at the CAV locations, and for recovering position information from the headers at CLV density. Data sectors do not start at headers and are not fitted regularly between the headers, but start and stop at arbitrary positions which are calculated from the known amounts of data recordable in the track portion.
摘要:
An optical disk has tracks with a groove wobbled in a radial direction and addressing information at predetermined positions along the track. Embossed pits at the predetermined positions represent addressing information. The phase of the wobble near the predetermined positions depends on whether a pit is present on a predetermined position or not.
摘要:
A method is described for optimizing recording conditions for writing information on an optical record carrier. The information is written on the record carrier in the form of optically detectable marks, each mark being written by a pulse series of radiation. A series of test patterns is written on the record carrier (1) for the optimization. A jitter detector (11) measures both the leading-edge and trailing-edge jitter of the read signal. The leading-edge jitter is used to optimize the value of a parameter influencing only the leading part of a pulse series. The trailing-edge jitter is used to optimize a parameter influencing only the trailing part of the pulse series.
摘要:
An optical recording medium having a recording layer with grooves that define recording tracks. The structure of unwritten tracks enable a scanning device to derive a radial tracking error signal using the push-pull method. The structure of the written tracks enable the scanning device to derive a radial tracking error signal using the high-frequency phase-detection method. The width of the groove is in the range from 0.3 to 0.6 time the wavelength over the numerical aperture for scanning the recording medium. The depth of the groove is in the range from 1/24 to 1/7 times the wavelength for scanning the recording medium. The phase difference between a radiation beam reflected from a track at a mark and a radiation beam reflected from that track in a region between written marks is in the range from 0.4 to 2.0 radians.