JP4341195B2 - DIGITAL SIGNAL GENERATION METHOD, INFORMATION RECORDING MEDIUM CONTAINING THE SAME, AND REPRODUCTION METHOD - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital signal generation method, and an information recording medium and a reproduction method for recording the same, and more particularly, a modulation process suitable for recording on a recording medium, a digital signal generation method generated by adding a synchronization signal, and the recording The present invention relates to an information recording medium and a reproducing method.
[0002]
[Prior art]
A DVD (Digital Versatile Disc) is an example of a disc recording medium that forms a frame by adding modulation processing to recording information and adding a synchronization signal indicating the beginning of a certain amount of data, and records a digital signal corresponding thereto as recording pits (marks). ). About this DVD, NIKKEI ELECTRONICS BOOKS "Data compression and digital modulation" 1998 edition pp. 121-123 and Japanese Patent Laid-Open No. 9-162857 describe the technique. A digital signal generation method in these techniques will be described with reference to FIG.
[0003]
In FIG. 2, sector data is composed of 2048 bytes of recording information which is one of the recording units on the disk and additional data including a sector ID number indicating the recording position on the disk, and 172 bytes of 16 sector data. An array of x12 rows x16 sectors is constructed. In this arrangement, PO and PI correction codes for error correction for vertical and horizontal series are generated and added to form a correction block. Further, the row data including the PO correction code is inserted between the row data including the sector data. An interleaved array is formed with equal intervals. Sequential values (0 to F) are given as sector ID numbers in the interleaved array. Further, 8-16 modulation processing and synchronization signal addition are performed to generate a frame. The generated frames are arranged as shown by the synchronization signals SY0 to SY7, and digital signals for the frames are recorded on the disc. By configuring the frame, burst error propagation due to loss of synchronization during playback can be prevented. At the time of reproduction, while performing frame synchronization by detecting the synchronization signal, the frame position is specified by the detection order of the synchronization signals SY0 to SY7, and the interleaved array is restored. Further, the correction block boundary is detected from the sector ID number, error correction is performed by decoding the correction code, and the original recorded information is reproduced.
[0004]
On the other hand, the configuration of the synchronization signal of SY0 to SY7 in Japanese Patent Laid-Open No. 9-162857, and the given bit pattern are connection bits {000} for satisfying the modulation law between the last bit pattern of the synchronization signal frame and the synchronization signal. {001} {100}, 32 bits of SY0 to SY7 identification pattern, 4T or more and -14T-4T bit pattern deviating from the maximum run length constraint of the 8-16 modulation rule.
[0005]
[Problems to be solved by the invention]
The problems in the above-described conventional technology will be described. Development of next-generation optical discs for the purpose of performing recording with a large capacity and a long time by performing high-efficiency encoding and high-density recording on the current DVD is in progress. High density recording is performed by reducing a recording mark (pit) using a short wavelength laser. High-efficiency encoding is performed by adopting a modulation system that suppresses the generation of redundant data and by suppressing the addition of redundant data. However, high-density recording discs have increased burst errors during playback due to dust and scratches on the disc, uneven recording mark formation during recording, and bit shift, recording, and playback due to slice level fluctuations during binarization during playback. Random errors due to physical disturbances such as time vibration increase. Accordingly, it is essential to correct random errors and burst errors sufficient for reproduction, frame synchronization that is not affected by bit shift, and specification of frame positions.
[0006]
Improvement of the correction capability can be solved by increasing the number of correction codes, adopting a correction code having a higher correction capability, and changing the data length to be encoded. However, in the current DVD digital signal generation method, the sector ID number is a clue for specifying the correction block boundary and the sector position in the correction block. In other words, at least the number of sectors included in the correction block needs to be 2, 4, 8, 16, 32, 64. Therefore, there is a problem that the number of correction codes is increased and the degree of freedom in changing the data length to be corrected is low.
[0007]
On the other hand, the influence of bit shift is considered to be burst error propagation by specifying an erroneous frame position due to erroneous detection of the synchronization signal. The erroneous detection of the synchronization signal accompanying the bit shift is affected by the similarity between the bit patterns of a plurality of types of synchronization signals. The similarity can be expressed by the number of inverted bits included in the bit pattern and the inter-code distance. The number of inverted bits referred to here is, for example, data included in a synchronization signal when NRZI (Non Return to Zero Inverted) recording is performed by inverting the state of a recording signal represented by a binary value only when the data bit is 1. This is the number of occurrences of bit “1”. Therefore, if the number of inversions differs between the synchronization signals, the similarity is low. As for the inter-code distance, the number of inversion bits with respect to the bit pattern of the sync signal is the same, and the number of shifts required to shift the position of the data bit “1” to coincide with another bit pattern of the sync signal is the inter-code distance. Define. Therefore, the similarity is low when the inter-symbol distance is 2 or more between the synchronization signals.
[0008]
In the above-mentioned Japanese Patent Laid-Open No. 9-162857, the synchronization signal is given a pattern common to all of the synchronization signals of 4T or more and -14T-4T which is 1T larger than the maximum interval 11T of the modulation rule and 1T larger than the minimum interval 3T. Yes. However, the connection bit and the identification pattern have a synchronization signal with a code distance of 1, and there is a problem that erroneous identification of SY0 to SY7 is likely to be performed by bit shift. In the worst case, an error that exceeds the correction capability of the correction code propagates, and there is a possibility that the error cannot be corrected, that is, cannot be reproduced.
[0009]
Therefore, an object of the present invention is to provide a digital signal generation method that solves the above problems, an information recording medium that records the method, and a reproduction method.
[0010]
[Means for Solving the Problems]
A method for solving the above problems in the present invention will be described below.
[0011]
A first data block including at least first additional data and recording information required for recording information on the recording medium is generated, and a second data block is configured by a plurality of first data blocks and second additional data. In a digital signal generation method for generating a plurality of frames by modulation processing and addition of a synchronization signal to a data block of at least a first synchronization signal and a second data for a frame located at the boundary of the first data block A second synchronization signal is provided for a frame located at a block boundary. This solution corresponds to the first embodiment.
[0012]
A first data block including at least first additional data and recording information required for recording information on the recording medium is generated, and a second data block is configured by a plurality of first data blocks and second additional data. In the digital signal generation method for generating a plurality of frames by adding modulation processing and a synchronization signal to the data block, at least the first additional data of the first data block located at the boundary of the second data block, The identification information indicating it is given. This solution corresponds to the second embodiment.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings.
[0014]
FIG. 1 is a diagram showing a first embodiment of a digital signal generation method according to the present invention. In FIG. 1, (A) shows the configuration of a data block 13 which is one of recording units on a disk recording medium, and is composed of at least data 2 and additional information 12. Further, the additional information 12 includes a sector ID indicating a recording position on the disk recording medium, a correction code for the ID, and the like. (B) shows the configuration of the correction block 3, which shows a unit after adding a plurality of data blocks and redundant data including correction codes for vertical and horizontal series shown in FIG. 2, for example. The correction block 3 is a unit that completes the encoding of the correction code. (C) shows a state in which the correction block and data block of (B) are divided into a plurality of frames 7. As in FIG. 2, the framing is performed by adding a synchronization signal indicating the boundary between frames after modulation processing for a certain amount of data. Regarding the synchronization signals SY0, SY1, and SY in (C), the first synchronization signal SY0 is added to the frame located at the boundary of the correction block 3. During reproduction, it is used to detect the boundary of the correction block. The second synchronization signal SY1 is added to the frame located at the boundary of the other data block 13. It is used for data block boundary detection during playback. The third synchronization signal SY is added to the frame located at the other boundary. However, the third synchronization signal is not limited to the same type and the same bit pattern. For example, it is possible to specify the frame position inside the data block from the detection order of the third synchronization signal detected continuously. (D) shows a configuration example of the first, second, and third synchronization signals. The synchronization signal is a connection bit 8 for connecting the last data of the previous frame and the synchronization signal while satisfying the modulation rule, and 9 is an identification code for identifying the first, second, and third synchronization signals. Reference numerals 9 and 10 are synchronization patterns common to the synchronization signals. The configuration of the synchronization signal may be only the connection bit and the synchronization pattern, and the first, second, and third synchronization signals may be identified from the synchronization pattern. In FIG. 1, bit patterns given to the first, second, and third synchronization signals will be described. In order to reduce the similarity between the synchronization signals, the bit patterns given to SY0, SY1, and SY are given bit patterns of two or more inter-code distances, different numbers of inverted bits, or combinations thereof.
[0015]
The digital signal generated by the method described above is recorded at high density as recording marks (pits) along the recording track on the disk recording medium.
[0016]
A method for reproducing original data from a disk recording medium will be described.
[0017]
A recording mark (pit) recorded on a track on the disc is read by an optical head and binarized to be converted into a digital signal before recording. A synchronization signal is detected for the digital signal, and synchronization in a frame unit and demodulation processing corresponding to the modulation rule are performed. The data block boundary is detected by detecting the second synchronization signal SY1 while performing frame synchronization, and the access to the vicinity of the target access position is controlled from the detection of the sector ID included in the boundary frame. When the first synchronization signal SY0 is detected after the accessed data block, it is determined as a correction block boundary, and the demodulated data from the head of the correction block is buffered on the buffer memory. From the start of buffering, every time the second synchronization signal SY1 is detected, synchronization is performed in units of data blocks, and synchronization is performed in units of frames by detection of the third synchronization signal SY. Synchronize with. Further, when the detection of the next first synchronization signal or the buffering of the data amount for the correction block is completed, the correction block is restored on the buffer memory. Accordingly, error correction processing by decoding correction codes is performed while performing random access to the buffer memory. After the correction is completed, the recorded information is reproduced by reading the data included in the data block from the buffer memory.
[0018]
The arrangement of the first synchronization signal indicating the boundary of the correction block and the second synchronization signal indicating the boundary of the data block is not limited to that shown in FIG. For example, it is conceivable to arrange the first synchronization signal SY0 in the last frame of the correction block (one frame before the correction block head) and the second synchronization signal SY1 in the boundary frame. Similarly in this case, a pattern having a low similarity between the first, second, and third synchronization signals is given.
[0019]
Further, the types and arrangements of the synchronization signals given for the purpose of detecting the boundary of the correction block are not limited to those shown in FIG. For example, it is conceivable that a plurality of types of synchronization signals are given between boundary frames from n data frames before the correction block boundary (n is a positive integer). For example, SY000 is 2 frames before, SY00 is 1 frame, and SY0 is a border frame. Further, there may be a case where SY00 is two frames before, SY0 is one frame before, and SY1 is a boundary frame. Similarly, bit patterns having low similarity are given to SY000, SY00, and SY0.
[0020]
According to the first embodiment described above, the first synchronization signal is in the frame located at the boundary of the correction block, the second synchronization signal is in the frame located at the boundary of the data block, and the third synchronization signal is in other frames. By adding a signal, it becomes possible to detect a correction block boundary independent of the sector ID number, and it is possible to configure a correction block having a high data amount and a high degree of freedom in configuration. In addition, by giving a pattern having a low similarity between the first, second, and third synchronization signals, it is possible to avoid specifying an erroneous frame position with respect to the correction block boundary and the data block boundary. Therefore, when reproducing the disc recording medium on which the generated digital signal is recorded, it is possible to reliably perform the correction block restoration, and to suppress the reproduction failure due to the burst error propagation due to the erroneous detection of the frame position.
[0021]
FIG. 3 is a diagram showing a second embodiment of the present invention. Eleventh identification information is included in the additional information 12 together with the sector ID1, and is provided for the purpose of identifying the data block located at the correction block boundary. ing. Other reference numerals are the same as those in FIG. In FIG. 3, (B) shows an arrangement example of values indicated by the identification information 11 included in the additional information of the data block constituting the correction block. (C) shows the frame arrangement for the correction block of (B), and the second synchronization signal SY1 is given to the frame indicating the correction block boundary or the data block boundary, and the third synchronization signal SY is given to the other frames. . In (B), “1” is given to the identification information for the data block at the correction block boundary, and “0” is given to the other data blocks. As for the bit patterns given to the second and third synchronization signals SY1 and SY in (C), patterns having low similarities are given in the same manner as in the first embodiment.
[0022]
Another example of an arrangement method of identification information for distinguishing correction block boundaries will be described with reference to FIG. In FIG. 4, (B-1) gives “1” to the identification information for the previous data block at the correction block boundary, and gives “0” for the other data blocks. (B-2) is “3”, “2”, “1”, “0” as identification information for the two data blocks before the correction block, the previous one data block, the data block at the correction block boundary, and the other data blocks, respectively. Is given. (B-3) assigns “2”, “1”, and “0” as identification information to the two data blocks before the correction block, the previous data block, the data block at the boundary of the correction block, and other data blocks, respectively. Yes. The identification information is not limited to the above example, and may be information that can detect the correction block boundary or the data block position in the correction block. Further, the number of data data blocks before the correction block boundary is not limited to the above example, and may be any number equal to or less than the number of data blocks constituting the correction block.
[0023]
The digital signal generated by the method described above is recorded at high density as recording marks (pits) along the recording track on the disk recording medium.
[0024]
A method for reproducing original data from a disk recording medium will be described.
Frame synchronization and demodulation processing are performed on the reproduced digital signal by detecting a synchronization signal, and a data block boundary is detected by detecting the second synchronization signal SY1 during frame synchronization. Access to the vicinity of the target position is performed by detecting the sector ID included in the boundary frame. Further, the correction block boundary is determined from the detected identification information, and buffering of data from the head of the correction block is started on the buffer memory. Each time the second synchronization signal SY1 is detected from the start of buffering, synchronization is performed in units of data blocks, and synchronization is performed in units of frames by detection of the third synchronization signal SY, thereby synchronizing the playback frame and buffering data. To do. Further, when the detection of the identification information or the buffering of the data amount for the correction block is completed, the correction block is restored on the buffer memory. Accordingly, error correction processing by decoding correction codes is performed while performing random access to the buffer memory. After the correction is completed, the recorded information is reproduced by reading the data included in the data block from the buffer memory.
[0025]
As for the detection method of the correction block boundary in the reproduction method, for example, in the case of FIGS. 4B-2 and B-3, it is possible to detect the data block located at the boundary from the permutation of the detected identification information. . Even if not all the identification information is detected, it is possible to predict from at least one identification information for the data block near the boundary and the number of elapsed data blocks.
[0026]
According to the second embodiment described above, by adding identification information in units of data blocks, it becomes possible to detect a correction block boundary independent of the sector ID number, and a correction block having a high degree of freedom in data amount and configuration. Can be configured. Further, by giving a bit pattern having a low similarity between the second and third synchronization signals, it is possible to avoid specifying an erroneous frame position with respect to the correction block boundary and the data block boundary. Therefore, when reproducing the disc recording medium on which the generated digital signal is recorded, it is possible to reliably perform the correction block restoration, and to suppress the reproduction failure due to the burst error propagation due to the erroneous detection of the frame position.
[0027]
The correction block boundary can be detected more reliably by combining the method of adding the first synchronization signal to the correction block boundary in the first embodiment and the identification information in the second embodiment.
[0028]
Further, the digital signal generated by the method described in the present invention is not limited to recording all the synchronous frames from the beginning to the end of the recorded information on a continuous track, and the physical signal in the disk is used as a pre-pit on the rewritable disk. The present invention is also applicable to a disc in which addresses are engraved and a frame for one sector or a frame for one correction block is written continuously in the signal recording area between the prepits, and the signal recording areas are discontinuous.
[0029]
【The invention's effect】
As described above, according to the present invention, the first synchronization signal is used for the frame located at the boundary of the correction block, the second synchronization signal is used for the frame located at the boundary of the data block, and the third synchronization signal is used for the other frames. By adding a synchronization signal, it becomes possible to detect a correction block boundary not depending on the sector ID number, and it is possible to configure a correction block having a high data amount and a high degree of freedom in configuration.
[0030]
Further, by giving a pattern having a low similarity between the first, second, and third synchronization signals, it is possible to reliably specify the frame position with respect to the correction block boundary and the data block boundary. Therefore, when reproducing the disc recording medium on which the generated digital signal is recorded, the detection accuracy for the correction block boundary and the sector data boundary is improved, and the inability to reproduce due to burst error propagation due to erroneous detection of the frame position is suppressed. Is possible.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment of a digital signal generation method according to the present invention.
FIG. 2 is a diagram showing an example of a method for generating a digital signal to be recorded on a disc.
FIG. 3 is a diagram showing a second embodiment of the digital signal recording method according to the present invention.
FIG. 4 is a diagram showing another example of arrangement of identification information.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Sector ID, 2 ... Data, 3 ... Correction block, 4 ... 1st synchronizing signal, 5 ... 2nd synchronizing signal, 6 ... 3rd synchronizing signal, 7 ... Frame, 8 ... Connection bit, 9 ... Identification Code: 10 ... synchronization pattern, 11 ... identification information, 12 ... additional information, 13 ... data block.

Claims (3)

A digital signal generation method for generating a frame including recording data, a second data block composed of a plurality of frames, and a first data block composed of a plurality of second data blocks,
A first synchronization signal is added as a synchronization signal to a frame located at the boundary of the first data block, and a synchronization signal is transmitted to a frame at a position that is the boundary of the second data block but not the boundary of the first data block. A second synchronization signal is added,
A third synchronization signal is added as a frame synchronization signal excluding a frame to which the first and second synchronization signals are given,
A digital signal generation method, wherein the number of inversions of the bit patterns of the first, second and third synchronization signals is different. A frame including recording data; a second data block including a plurality of frames; and a first data block including a plurality of second data blocks;
A first synchronization signal is added as a synchronization signal to a frame located at the boundary of the first data block, and a synchronization signal is transmitted to a frame at a position that is the boundary of the second data block but not the boundary of the first data block. A second synchronization signal having a different number of bit pattern inversions from the first synchronization signal is added, and a third synchronization signal is added as a frame synchronization signal excluding a frame to which the first and second synchronization signals are applied. For recording media on which recorded digital signals are recorded,
The detection of the first synchronization signal identifies the boundary of the first data block, the detection of the second synchronization signal identifies the boundary of the second data block, and the third synchronization signal detects the third boundary . A method for reproducing a digital signal, wherein the boundary of the data block is specified and the recorded information is reproduced. A frame including recording data; a second data block including a plurality of frames; and a first data block including a plurality of second data blocks;
A first synchronization signal is added as a synchronization signal to a frame located at the boundary of the first data block, and a synchronization signal is transmitted to a frame at a position that is the boundary of the second data block but not the boundary of the first data block. A second synchronization signal is added,
A third synchronization signal is added as a frame synchronization signal excluding a frame to which the first and second synchronization signals are given,
A disc-shaped information recording medium, wherein digital signals having different numbers of inversions of bit patterns of the first, second and third synchronizing signals are recorded.

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