JP5156509B2 - Digital signal recording method and information recording medium - Google Patents

Description

  The present invention relates to a digital signal recording method and an information recording medium, and more particularly, to a recording pit (mark) on a disk recording medium for a digital signal corresponding to a synchronization frame generated by modulating a recording information and adding a synchronization signal. ) As a digital signal recording method and information recording medium.

  A synchronization frame is formed by adding a synchronization signal indicating the head in a fixed amount of data unit after modulation processing is performed on the recorded information, and the digital signal corresponding to the synchronization frame is recorded on a recording pit (mark As an example of a disc recording medium to be recorded as (), there is a DVD (Digital Versatile Disc). The technique for generating a digital signal for this DVD is described in Non-Patent Document 1 and Patent Document 1 in the well-known example. This technique will be described with reference to FIGS. 2, an array in which information unique to a sector such as a sector ID number indicating a recording address on the disk is added to recording information of 2 kilobytes (2048) stored in a sector which is a recording unit on the disk, 172 Sector data is composed of bytes × 12 rows, and then, for an array of 172 bytes × 12 rows × 16 sectors = 32 kilobytes in which 16 pieces of sector data are collected, a PO correction code of 16 bytes for a vertical sequence, a horizontal sequence A correction block is configured by adding a PI correction code of 10 bytes, and for a row data including a PO correction code, an interleaved array is configured by distributing one row for every 12 rows of sector data. Further, by performing 8-16 modulation processing and adding a synchronization signal to the row data included in the interleaved array, two synchronization frames are generated per row. Regarding the arrangement method of the eight kinds of synchronization signals SY0 to SY7 for the generated synchronization frame, one synchronization signal of SY0 is included in the first synchronization frame from the first synchronization frame including the sector ID number to 26 synchronization frames for the PO correction code. Are arranged and arranged in the order of SY5, SY1, SY5,. Further, digital signals for the synchronization frames are continuously recorded on the disc in accordance with the arrangement order of the synchronization signals, SY0, SY5, SY1, SY5,. For the 8-16 modulation process, an RLL (Run Length Limited) encoding method is used. When T is a unit of recording bit (mark) interval on the disk, the minimum run length d = 2T and the maximum run length k = The 8-bit data included in the row data is converted into a 16-bit (1 word) code word so as to satisfy the 10T run length limit. The number of synchronization frames for row data is composed of two frames for the purpose of easily performing synchronization pull-in in units of synchronization frames and preventing error propagation due to loss of synchronization. As for the arrangement of the synchronization signals SY0 to SY7 for the 26 synchronization frames, SY0 is given only once for the first synchronization frame including the sector ID number so that the frame position within one sector can be specified. SY1 to SY4 are arranged in a periodic manner for the left synchronization frame, and each of SY5, SY6, and SY7 is divided into three areas so that one sector is divided into three areas in the right synchronization frame. It is added continuously. FIG. 3 shows the configuration of the synchronizing signals SY0 to SY7 shown in the above-mentioned known example and the bit pattern to be given. The synchronization signal is composed of 32 bits, and three types of connection bits {000} {001} {100 for keeping the restrictions on the minimum run length and the maximum run length between the last code word included in the synchronization frame and the synchronization signal. } And the identification pattern of the synchronization signals SY0 to SY7, the bit pattern of 4T or more and -14T-4T including the bit pattern deviating from the restriction of the maximum run length, and the synchronization pattern common to all the synchronization signals SY0 to SY7 Composed.

  A total of 32 types of synchronization signals are constituted by the types of connection bits, and are classified into (a-1), (a-2), (b-1), and (b-2) in FIG. Addition of each classified sync signal is performed by selecting an optimum bit pattern that satisfies the minimum run length and maximum run length constraints according to the immediately preceding code word and that minimizes the DC component in the digital signal for the sync frame. . For example, even if the synchronization signal SY0 is a bit pattern indicating the same synchronization signal SY0 depending on the connection bit and the identification pattern, the connection bit pattern is different for the purpose of satisfying the restrictions on the minimum run length and the maximum run length with respect to the immediately preceding code word ( a-1), (a-2), (b-1), and (b-2). Furthermore, even for the same connection bit for the purpose of suppressing the DC component, the identification pattern is different (a-1). ) And (a-2) or (b-1) and (b-2) in total. At the time of frame reproduction, data synchronization is performed in units of frames by detecting the synchronization signal, and the frame position within one sector is detected from the continuous detection result of the synchronization signals SY0 to SY7, and the detection result and the sector ID number are detected. The original recorded information is reproduced by restoring the original interleaved array from the result and performing error correction processing by decoding the correction code.

NIKKEI ELECTRONICS BOOKS Data compression and digital modulation 1998 edition pp.121-123 JP-A-9-162857

  FIG. 4 shows the case where the similarity between the bit patterns of the synchronization signal in the above-described prior art is shown using the number of inverted bits and the inter-code distance. Here, the number of inverted bits means that the recording mark (pit) formed on the disk is inverted and NRZI (Non Return to Zero Inverted) recording is performed only when the data bit included in the synchronization frame is 1. The number of appearances of the data bit “1” included in the bit pattern of the synchronization signal is counted, and the similarity of the bit pattern decreases as the number of inversions increases with respect to other synchronization signals. Regarding the inter-code distance, the number of inverted bits with respect to the bit pattern of the synchronization signal is the same, and the number of shifts required to shift the position of the data bit “1” to coincide with the bit pattern for another synchronization signal is given as the inter-code distance. . FIG. 4 shows the synchronization signal with the inter-code distance = 1 for the number of inverted bits and the synchronization signals SY0 to SY7 for each classification of the synchronization signal. In each of the classifications (a-1), (a-2), (b-1), and (b-2), in particular, a synchronization signal having a code-to-code distance of 1 is shifted by 1 bit as another synchronization signal. Likely to be identified. On the other hand, at the time of disc reproduction, slice level adjustment is performed when the reproduction signal is binarized (digitized). In an unstable state in which the slice level adjustment fluctuates, or in a state where inter-code interference occurs in adjacent recording marks (pits), the bit that is shifted by 1 bit before and after the original bit position is binarized. Shift easily occurs. Therefore, in consideration of bit shift, the synchronization pattern constituting the synchronization signal is 3T outside the maximum interval 11T due to the maximum run length constraint after 8-16 modulation, and 1T greater than the minimum interval 3T due to the minimum run length constraint 4T A common synchronization pattern is given to all the synchronization signals of -14T-4T. However, with respect to the connection bits and identification patterns in the synchronization signal, as shown in FIG. 4, there is a synchronization signal with an intersymbol distance of 1, so that the synchronization signals SY0 to SY7 are erroneously identified by bit shift. For write-once discs and rewritable discs in particular, they may be slightly longer or shorter than the original mark length due to physical disturbances such as vibration when recording marks are formed on the disc, and uneven recording mark formation. Yes, in order to increase the storage capacity of the disc, if the track pitch on the recording medium and the recording mark (pit) length are made finer and high density recording is performed, the disturbance during the above mark formation and the formation unevenness of the recording mark are affected. Bit shifts are expected to occur frequently due to disturbances during playback. A problem will be described when the erroneous identification of the synchronization signal due to the bit shift occurs in, for example, 26 synchronization frames per sector shown in FIG.

  In FIG. 2 (c), for example, when specifying the frame position in one sector by identifying the synchronization signal for three consecutive frames, for example, out of 26 frames, the synchronization signal SY5 of the sixth frame is bit-shifted due to bit shift. When the distance is mistakenly identified as SY7, the continuous synchronization signal of SY2-5-3 becomes SY2-7-3 in the seventh frame reproduction, and the correct frame continuity SY3-5 in the subsequent frame reproduction. Two frames between the ninth frames in which -4 is established are erroneously identified as the 23rd to 24th frames in one sector. In this case, although the burst position is not a burst error due to scratches or dust generated on the disk, the frame position specification is incorrect, so a loss occurs in the seventh to eighth frames in one sector, and a burst-like error occurs. Will occur. Further, for example, if SY7 in the 24th and 26th frames is mistakenly identified as SY5 with the intersymbol distance = 1 due to the bit shift, the continuity of the synchronization signal of SY7-4-7 is established in the reproduction of the 26th frame. SY5-4-5 and the erroneous frame position is determined to be the 10th frame. In the subsequent frame reproduction, the correct frame continuity SY0-5-1 is established from the third frame of the next sector, and the frames up to the synchronization frame of the next sector are determined as frames in the current sector. Even if SY0 can be detected correctly in the meantime, the continuity of SY4-7-0 is not established and the frame position at the head of the sector cannot be detected. Therefore, the sector ID number included in the head of the synchronization frame SY0 is not detected, that is, the area to the next sector is not updated in the interleave block shown in FIG.

  Therefore, the 26 frames of the synchronization frame until the next sector ID number is detected is regarded as a frame in the previous sector without updating the sector, and the 26 frames included between them are updated. Will be lost completely, and the number of burst error frames will be 50 frames in total, 24 frames from the third frame where SY0-5-1 is established and 26 frames where sector loss has occurred. . In this case, since the number of correctable bytes of the PO correction code in the correction block in FIG. 2A is exceeded, correction is impossible, that is, reproduction of the original recorded information is impossible. When playback is not possible, an operation is performed to read again a sector that cannot be corrected again by retry operation. However, if the recorded information is video or audio data, for example, depending on the relationship between the bit rate and the transfer rate to the disc The problem is that the playback video and playback audio are interrupted, and the retry operation cannot be repeatedly executed. In particular, in a high-density disk that generates recording marks at a high density, it is expected that corrections that cannot be corrected due to erroneous identification of the frame position due to the above-described bit shift, that is, reproduction failures, will frequently occur.

  In the above case, the above problem can be avoided by increasing the number of consecutive frames when performing position determination within one sector to 4 frames and 5 frames. However, when the number of consecutive frames to be determined is, for example, 7 or 8 frames or more, if the synchronization signal of the continuous frame is not detected or erroneous synchronization signal identification by bit shift is performed even in one frame, naturally The frame position cannot be determined, and the number of frames required until the next frame continuity is established increases. The same problem occurs when the frame position is specified by detecting only the synchronization signal of SY0 having the maximum number of inverted bits and the maximum intersymbol distance. In this case, there is a discrepancy between the playback frame on the disc and the identification of the frame position when there is a sudden fluctuation in disc rotation, a scratch on the disc, or a burst error due to dust, etc. The number of mismatched frames increases. Accordingly, since the number of burst error frames increases, the number of determination frames cannot be increased.

  On the other hand, if the inter-code distances between the synchronization signals SY0 to SY7 are all set to 2 or more, or if a bit pattern having different numbers of inverted bits is given, the problem due to the bit shift is solved, the bits assigned to the synchronization signals This is not practical because there is a limit on the number or the amount of redundant data not related to recorded information increases.

  Accordingly, an object of the present invention is to provide a digital signal recording method and an information recording medium that solve various problems caused by erroneous detection of the frame position.

  In order to solve the above problem in the present invention, when the data included in the sector is divided into a plurality of frames including the synchronization signal and recorded on the recording medium, the synchronization signal is a synchronization pattern including at least the identification pattern of the synchronization signal. A method for solving this problem is to provide a bit pattern for a synchronization signal that is configured and that is necessary for specifying a frame position within one sector by detecting an identification pattern included in the synchronization signal of several consecutive frames. The method in the present invention is shown in the following (1) to (5).

  (1) At least n frames (n is a positive integer) before a synchronization frame including address information indicating a recording position on a recording medium with respect to a sector, a bit pattern given to an n-frame synchronization signal included in the range is The intersymbol distance is 2 or more. Alternatively, bit patterns having different numbers of inverted bits are given. This solution corresponds to the third embodiment.

  (2) At least n frames (n is a positive integer) before the synchronization frame including address information indicating the recording position on the recording medium with respect to the sector, and k frames (k is a positive integer and k < n) Bit patterns given to every other synchronization signal have an inter-code distance of 2 or more. Alternatively, bit patterns having different numbers of inverted bits are given. This solution corresponds to the fourth embodiment.

  (3) The same first, second,..., Nth synchronization signal (n is a positive integer) is continued every k frames (k is a positive integer) for at least a plurality of frames included in a sector. When dividing one sector into the first, second,..., Nth areas, the first, second,..., Nth synchronization signals every k frames included in each area. The given bit patterns have a distance between codes of 2 or more. Alternatively, bit patterns having different numbers of inverted bits are given. This solution corresponds to the first embodiment.

  (4) The same first, second,..., N-th synchronization signal (n is a positive integer) is continued every k frames (k is a positive integer) for at least a plurality of frames included in a sector. When the sector is divided into the first, second,..., Nth areas, the first, second,..., First included in each of the (n−1) areas. The bit pattern given to the (n-1) th synchronization signal and the bit pattern given to the nth synchronization signal included in the nth area including the sector last frame have an inter-code distance of 2 That's it. Alternatively, bit patterns having different numbers of inverted bits are given. This solution corresponds to the second embodiment.

  (5) The same first, second,..., Nth synchronization signal (n is a positive integer) for each of a plurality of frames included in at least a plurality of frames, and k frames (k is a positive integer). When one sector is divided into first, second,..., Nth areas by arranging them consecutively, the first, second,..., Nth synchronization of consecutive k frames included in each area. The bit patterns given to the signals have an inter-code distance of 2 or more. Alternatively, bit patterns having different numbers of inverted bits are given. This solution corresponds to the fifth embodiment.

  As described above, according to the present invention, when one sector is divided into a plurality of synchronization frames and recorded on a disk recording medium, the inter-code distance is 2 or the number of inverted bits is different with respect to the synchronization signals in the plurality of frames. By arranging the bit pattern, erroneous identification of the frame synchronization signal due to bit shift can be avoided, and burst-like error frame propagation due to erroneous determination of the frame position within one sector can be prevented. It is possible to keep the propagation of the error frame within at least one sector, and it is possible to prevent the reproduction failure.

  The present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a first embodiment of a digital signal recording method according to the present invention, showing an example of a digital signal recording method for avoiding erroneous frame position identification within one sector by bit shift. is there. In FIG. 1, reference numeral 1 is given only once to a synchronization frame including a sector ID among 26 frames included in one sector, and a leading synchronization signal indicating that it is the leading frame of the sector, 2 is on the disk A sector ID indicating a recording position in a sector unit and including at least a sector ID number, 3 is a last code word of the previous frame, that is, a run code among constituent elements of a synchronization signal added to the head of each of 26 frames constituting one sector. A bit that indicates the type of synchronization signal while satisfying the maximum run length and minimum run length constraints together with the connection bits, and a connection bit that is added to satisfy the maximum run length and minimum run length constraints for the length limited code A connection consisting of identification bits to which patterns are assigned, identification bits 4 and 4 are shared by all synchronization signals. Is a common sync pattern indicating the head of each frame, 5 is a frame position indicating the position of each of the 26 frames included in one sector, and 6 is a disk position composed of 26 frames. Indicates a sector which is one of the recording units.

  In FIG. 1, the synchronization signals added to the head of each of the 26 frames included in one sector are SY0 to SY7, and the arrangement of the respective synchronization signals for each frame is shown. Further, by showing a part of the frame arrangement in the preceding and succeeding sectors, the arrangement relationship of the frame synchronization signals between the sectors is shown. The frame division in FIG. 1 is, for example, 2 frames per row data in the interleaved array shown in FIG. 2B, and the arrangement of the synchronization signals SY0 to SY7 is the first synchronization signal in the frame including the sector ID2. SY0 is given, and SY1 to SY4 are periodically repeated for the left frame, the synchronization signal SY5 for the right frame is arranged for 5 frames, and the synchronization signals SY6 and SY7 are arranged for 4 consecutive frames. As a result of arranging the synchronization signals SY0 to SY7, the sector is divided into three areas of SY5 area, SY6 area, and SY7 area within one sector, and the area is determined by identifying the synchronization signals of SY5, SY6, and SY7. Identified. Further, the frame position is specified by identifying the synchronization signals SY0 and SY1 to SY4 in each region. Assume that at least the connections included in the synchronization signals of SY5, SY6, and SY7 and the number of inverted bits of the bit patterns included in the identification bit 3 and the common synchronization pattern 4 are the same. In this case, at least all bit patterns given to the synchronization signals SY5, SY6, and SY7 in order to prevent propagation of bursty error frames caused by erroneous identification of the frame position due to erroneous identification of the synchronization signal by bit shift. On the other hand, the inter-code distance between the bit patterns of SY5 and SY6, SY5 and SY7, and SY6 and SY7 is set to 2 or more, and the similarity between the bit patterns is lowered. In this case, even if a 1-bit shift occurs in each of the synchronization signals SY5, SY6, and SY7 in the three areas divided within one sector, the inter-symbol distance is 2, and at least between the areas of SY5, SY6, and SY7. The synchronization signals that are wrong from each other are not identified. In other words, by specifying the frame position within one sector in, for example, several consecutive frames, the frame position relative to another area is not specified within each of SY5, SY6, and SY7, and error frame propagation within the sector Can be prevented. Furthermore, in the SY5 and SY6 areas, the prediction of the first frame of the next sector performed in the SY7 area is not performed, and propagation of an error frame beyond the sector can be prevented. Even when SY0 to SY4 are identified by bit shift or when they are not identified, the frame position within one sector is specified by, for example, three consecutive frames so that the frame position can be specified from the previous specific position. Therefore, the reproduced frame and the frame position identification result coincide with each other, and an error frame like a burst error does not occur. Further, even when SY5, SY6, and SY7 having different numbers of inversion bits are provided to reduce the similarity between the bit patterns, it is possible to prevent the occurrence of an error frame. For example, it is conceivable to give a bit pattern in which the number of inversion bits between SY5, 6, and 7 has a relationship of (SY7)> (SY6)> (SY5).

  In the first embodiment described above, in order to more accurately specify the frame position within one sector, the bit pattern of each of the synchronization signals {SY5, SY6, SY7} and the synchronization signals SY0, SY1, SY2, SY3, SY4 The relationship between the given inter-code distance and the number of inverted bits will be described.

  In order to reduce the similarity of the sync signal bit pattern between {SY5, SY6, SY7} and SY0 or {SY1, SY2, SY3, SY4}, which divide the area in one sector, the inter-code distance between them Give two or more bit patterns or bit patterns having different numbers of inverted bits. For example, in each combination between {SY5, SY6, SY7} and SY0, {SY5, SY6, SY7} and {SY1, SY2, SY3, SY4}, and further between SY0 and {SY1, SY2, SY3, SY4} A bit pattern having a distance between codes of 2 or more is given.

  When the number of inverted bits is different, for example, a bit pattern having a relationship of SY0> {SY5, SY6, SY7}> {SY1, SY2, SY3, SY4} is given.

  Furthermore, by combining a bit pattern having an inter-code distance of 2 or more and a bit pattern having a different number of inverted bits, it is possible to suppress an increase in the number of bits that can be assigned to the synchronization signal and to reduce the similarity between the bit patterns. . For example, the relationship between the numbers of inverted bits is SY0> {SY5, SY6, SY7}> {SY1, SY2, SY3, SY4}, and {SY5, SY6, SY7} and {SY1, SY2, SY3, SY4} In each combination, a bit pattern in which the number of inverted bits is the same and the distance between the codes is 2 or more is given. Or, for example, the intersymbol distance between the combinations of SY0 and {SY5, SY6, SY7} and {SY1, SY2, SY3, SY4} is set to 2 or more and the number of inverted bits is {SY5, SY6, SY7}. In SY7> SY6> SY5, for example, {SY1, SY2, SY3, SY4} gives a bit pattern having a relationship of SY1> SY2> SY3> SY4, for example. In this case, there may be a bit pattern in which the number of inverted bits is the same among combinations of {SY5, SY6, SY7}, {SY1, SY2, SY3, SY4}. For example, the number of inverted bits may be the same for SY7 and SY1, SY6 and SY2, and SY5 and SY3. However, as for the inter-code distance, two or more bit patterns are given to each other in the combination, and the similarity between the bit patterns is low.

  For example, the relationship of the number of inversion bits is SY0> SY7> SY6> SY5> {SY1, SY2, SY3, SY4}. In the combination of {SY1, SY2, SY3, SY4}, the number of inversion bits is the same. When a bit pattern is given such that the inter-code distance is 2 or more, or the relationship of the number of inverted bits is, for example, SY0> SY1> SY2> SY3> SY4> {SY5, SY6, SY7}, and {SY5, SY6 , SY7} may have a bit pattern in which the number of inverted bits is the same and the distance between the codes is 2 or more.

  As for SY0, it is desirable that the degree of similarity with the bit pattern with respect to other synchronization signals is the lowest, but the number of inverted bits with respect to other synchronization signals may be the same, or the intersymbol distance may be 1. For example, the number of inverted bits may be the same between SY0 and {SY5, SY6, SY7}, and the inter-code distance may be 2 or more.

  On the other hand, all bit patterns in the combination of {SY1, SY2, SY3, SY4} are not limited to having an inter-code distance of 2 or more or different in the number of inverted bits. It is also conceivable to reduce the degree of similarity of bit patterns in {SY1, SY2, SY3, SY4} while suppressing an increase in the number of bits that can be assigned to the synchronization signal by combining bit patterns having different numbers of inverted bits. For example, the relationship of the number of inverted bits is given as {SY1, SY2}> {SY3, SY4}, and the number of inverted bits is the same in each combination of {SY1, SY2}, {SY3, SY4}, and the inter-code distance In some cases, a bit pattern that gives 2 or more is given.

  Also, all bit patterns in the combination of {SY5, SY6, SY7} are not limited to bit patterns having a code distance of 2 or more or different in the number of inverted bits, but are bit patterns having a code distance of 2 or more. It is also conceivable to reduce the degree of similarity between the bit patterns in {SY5, SY6, SY7} while suppressing an increase in the number of bits that can be assigned to the synchronization signal by combining bit patterns with different numbers of inverted bits. For example, the number of inverted bits is set to have a relationship of SY7> {SY5, SY6}, and there may be provided a bit pattern in which the number of inverted bits is the same for SY5 and SY6 and the distance between codes is 2 or more.

  FIG. 5 is a diagram showing a second embodiment of the present invention. At least the connections included in the synchronization signals of SY5, SY6, and SY7, and the number of inversion bits included in the identification bit 3 and the common synchronization pattern 4 are the same. Assuming that SY5 and SY6 are at least for all the bit patterns given to SY5, SY6, and SY7 in order to prevent propagation of bursty error frames when the synchronization signal is erroneously identified by bit shift The inter-code distance remains 1, and for SY7, a bit pattern having a inter-code distance of 2 or more is given between SY5 and SY6, and the bit pattern similarity between SY7 and SY5 and SY7 and SY6 is low. The case is shown.

  In this case, even if a 1-bit shift occurs in the synchronization signals of SY5, SY6, and SY7 in the three areas divided within one sector, the intersymbol distance is 2, so that an erroneous synchronization signal SY5, at least in the area of SY7, The identification of SY6 is not performed, and the erroneous synchronization signal SY7 is not identified even in the area of SY5 and SY6. In other words, by specifying the frame position in one sector in, for example, several consecutive frames, the prediction of the first frame of the next sector in the SY7 area is not reliably performed in the SY5 and SY6 areas. Propagation of error frames across sectors can be prevented. Propagation of error frames exceeding the above sector even when the number of inversion pits is maximum and SY0 is the maximum by giving different bit patterns between inversion bits (SY5, SY6) and SY7. It is possible to prevent at least. For example, it is conceivable to provide a bit pattern in which the number of inversion bits between SY5, 6, and 7 has a relationship of (SY7)> (SY6, SY5). Alternatively, for example, a bit pattern in which the inter-code distance is 2 between SY7 and (SY6, SY5) is assigned by combining the inter-code distance and the number of inverted bits, and a different inverted bit number is given to the bit pattern of SY6, SY5, or On the other hand, it is possible to give Y7 and (SY6, SY5) bit patterns having different numbers of inverted bits, and to give a bit pattern having a code distance of 2 between SY5 and SY6.

  Also in the second embodiment described above, in order to more accurately specify the frame position in one sector, {SY5, SY6, SY7}, SY0, {SY1, SY2, SY3, SY4 described in the first embodiment are used. }, A bit pattern having an inter-code distance of 2 or more and a different number of inverted bits is similarly given.

  FIG. 6 is a diagram showing a third embodiment of the present invention, in which a frame before the first frame of the next sector from the frame of the head synchronization signal SY0 indicating the head of the sector is at least m frames (m is a positive integer). This shows a method of dividing a frame into n frames (n is a positive integer) and arranging synchronization signals having bit patterns with low similarity to each other. In FIG. 6, for example, (m + n) of SY (m + n) indicates a frame position in one sector, and one sector is composed of a total of (m + n) frames. In this (m + n) frame, in the n frames before the first frame of the next sector including the sector ID, all the bit patterns given to the synchronization signals SY (m + 1) to SY (m + n) included in these n frames By setting the distance to 2 or more, the similarities are reduced to each other. In this case, for example, if the number of consecutive frames for determining the frame position is k frames (k is a positive integer and k ≦ n), the inter-code distance is 2 even when a 1-bit shift occurs in the last n frames of the sector. Therefore, the frame position is correctly identified, and the propagation of the error frame across the next sector can be prevented. In particular, by setting the number of frames for determining the frame position to be k <n, the frame position can be determined several times within at least the n-frame region, and the frame position can be reliably identified. Further, even when SY (m + 1) to SY (m + n) having different numbers of inversion bits of all the synchronization signals included in the n frame are provided with the maximum number of inversion pits SY (0), the error frame extending over the next sector described above. Can be prevented. For example, a bit pattern in which the number of inverted bits between SY (m + 1) to SY (m + n) is in the relationship of SY (m + n)> SY (m + n-1)>...> SY (m + 2)> SY (m + 1) is given. It is possible.

  Also in the third embodiment described above, the inter-code distance given to the bit pattern of the synchronization signal for the n frame before the frame including the sector ID and the other m frames in order to more accurately specify the frame position within one sector. The relationship between the number of inverted bits will be described.

  In order to reduce the similarity of the bit pattern between the combination of the synchronization signals included in the n frames that divide the area in one sector and the combination of the synchronization signals included in the m frames, the intersymbol distance between them is It is conceivable to provide two or more bit patterns or bit patterns having different numbers of inverted bits. For example, a bit pattern having an intersymbol distance of 2 or more is given between a combination of all synchronization signals included in n frames and a combination of all synchronization signals included in m frames. When the number of inverted bits is different, for example, a bit pattern that gives a relationship of {a combination of all synchronization signals included in n frames}> {a combination of synchronization signals included in m frames} is given.

  In addition, due to the limitation on the number of bits allocated to the synchronization signal, the bit pattern similarity may be lowered by a combination of a bit pattern having an inter-code distance of 2 or more and a bit pattern having a different number of inverted bits. For example, the relationship of the number of inverted bits is given as {combination of synchronization signals included in n frame}> {combination of synchronization signals included in m frame}, and combination of synchronization signals included in n frame, synchronization included in m frame In each combination of signals, a bit pattern is provided in which the number of inverted bits is the same and the inter-code distance is 2 or more. Alternatively, {combination of synchronization signals included in n frame} and {combination of synchronization signals included in m frame} give bit patterns having different numbers of inverted bits, and {combination of synchronization signals included in n frame} And {combination of synchronization signals included in m frame} may be given bit patterns having an intersymbol distance of 2 or more. Also in this case, there is a bit pattern having the same number of inverted bits in a combination of the synchronization signals included in the n frame and a part of the combination of the synchronization signals included in the m frame. Therefore, the similarity of bit patterns is low.

  The bit patterns of the sync signals included in the n frame are all given bit patterns having different numbers of inverted bits, and the bit patterns of the sync signals included in the m frame are all the same in inverted bits, and the inter-code distance Is included in n and m frames by giving a bit pattern of 2 or more to each other, or vice versa for n frames by giving a bit pattern with a different number of inverted bits to each other. It is also conceivable to reduce the degree of similarity of the sync signal bit pattern. In this case, for example, there may be a case where the number of inverted bits of the synchronization signal included in the n frame is the same as the number of inverted bits included in the m frame. The similarity between patterns is low.

  On the other hand, all the bit patterns in the synchronization signal included in the m frame are not limited to having an inter-code distance of 2 or more or different in the number of inverted bits. It is also conceivable to reduce the similarity between all the synchronization signals included in the m frame by combining different bit patterns. For example, in m frames, every 1 or more frames are subdivided from the first divided area into k-th (k is a positive integer) divided areas, and the number of inverted bits of the synchronization signal for these divided areas is {first divided Region}> {second divided region}>...> {Kth divided region}, and the bit pattern of the synchronization signal included in each of the first to kth divided regions is In combination, the number of inverted bits is the same, and a bit pattern in which the distance between codes is 2 or more is given, or {first divided area}, {second divided area},... {Kth Division area} giving different inverted bit numbers to the synchronization signals included in each combination, and each combination of {first division area}, {second division area},... {Kth division area} The intersymbol distance between each other It is to give a bit pattern comprising 2 or more.

  In addition, the bit pattern in the synchronization signal included in the n frame is not limited to a bit pattern having an inter-code distance of 2 or more or a different number of inverted bits. It is also conceivable to reduce the degree of similarity between bit patterns by combining different bit patterns. For example, in n frames, every frame of 1 frame or more is subdivided from the first divided area into the h-th (h is a positive integer) divided area, and the number of inverted bits of the synchronization signal for these divided areas is {first divided Region}> {second divided region}>...> {Hth divided region} and the bit pattern of the synchronization signal included in each of the first to hth divided regions is In the combination, the number of inverted bits is the same, and a bit pattern in which the distance between codes is 2 or more is given, or {first divided region}, {second divided region},. Division area} giving different inversion bit numbers to the synchronization signals included in each combination, and each combination of {first division area}, {second division area}, ... {h-th division area} The intersymbol distance between each other It is to give a bit pattern to be the least.

  FIG. 7 is a diagram showing a fourth embodiment of the present invention, wherein at least m frames (m is a positive integer) are frames before the first frame of the next sector from the frame of the head synchronization signal SY0 indicating the head of the sector. This shows another method of dividing a frame into n frames (n is a positive integer) and arranging synchronization signals having bit patterns with low similarity to each other. Also in FIG. 7, for example, (m + n) of SY (m + n) indicates a frame position within one sector, and one sector is composed of a total of (m + n) frames. In the n frames before the first frame of the next sector including the sector ID in this (m + n) frame, for example, the synchronization signals SY (m + 1) to SY (m + n) included in these n frames are given to every other frame. By setting the intersymbol distance to 2 or more for all the bit patterns to be obtained, bit patterns having low similarity are given. Also in this case, for example, if the number of frames for determination of the frame position is k frames (k is a positive integer and k ≦ n), even if a 1-bit shift occurs in the last n frames of the sector, the code interval between every other frame Since the distance is 2, the frame position is correctly identified, and propagation of an error frame across the next sector can be prevented. In particular, by setting the number of frames for determining the frame position to k <n, it is possible to determine the frame position several times within the n-frame region, and to reliably identify the frame position at least within the n-frame region. It becomes possible. SY (m + 2), SY (m + 4),... SY (m + n), where the number of inverted pits is the largest and SY (m + 2) is different every other frame with respect to the synchronization signal included in n frames. It is possible to prevent the propagation of the error frame across the above-mentioned next sector even when. For example, it is conceivable to provide a bit pattern in which the number of inverted bits is in the relationship of SY (m + n)> SY (m + n−1)>...> SY (m + 4)> SY (m + 2). In the fourth embodiment, when giving a bit pattern with an inter-symbol distance of 2 in n frames or a bit pattern with a different number of inverted bits, it is not limited to the above example, but every second, third, fourth,. Alternatively, a bit pattern with an inter-symbol distance of 2 given every several frames, or a bit pattern with a different number of inverted bits may be given consecutively in 2, 3, 4.

  Also in the fourth embodiment described above, in order to more accurately specify the frame position within one sector, between the codes given to the bit patterns of the synchronization signal for the n frame preceding the frame including the sector ID and the other m frames. The same method as that described in the third embodiment is applied to the relationship between the distance and the number of inverted bits.

  As for the bit pattern for the synchronization signal included in the n frame, a bit pattern having a distance of 2 or more between codes or a bit pattern having a different number of inverted bits is given for each frame of one frame or more, and a bit pattern having a low similarity is given by a combination thereof. It is not limited to this, and for all the synchronization signals included in the n frame, the similarity of the bit pattern with respect to the synchronization signal may be lowered by a combination of the inter-code distance and the number of inverted bits. For example, among n frames, the relationship between the number of inverted bits (the code included in the n frame) is set for a synchronization signal that gives a bit pattern of two or more inter-code distances for each frame of one or more frames, or for other frames. (Synchronization signal having a distance of 2 or more)> (other synchronization signals included in n frames). Furthermore, it is conceivable to reduce the degree of similarity between the bit patterns of all the synchronization signals by giving a bit pattern in which the distance between the symbols is 2 or more for other synchronization signals included in the n frame.

  FIG. 8 is a diagram showing a fifth embodiment of the present invention. For example, p frames (p is a positive integer), q from the frame corresponding to the head synchronization signal indicating the sector head to the frame before the next sector head frame, q When dividing into three areas of frame (q is a positive integer) and r frame (r is a positive integer), the inter-code distance is 2 or the number of inverted bits for 2 frames including the last frame of each area. A method of arranging synchronization signals having different similarities with each other is shown. In FIG. 8, for example, (p) of SY (p) indicates a frame position included in one sector, and one sector is composed of total (p + q + r) frames. In this (p + q + r) frame, for example, the last two frames SY (p-1) and SY (p) of the first area, and similarly SY (q-1), SY (q), third area of the second area The bit patterns are given to the SY (r-1) and SY (r) frames so that the inter-symbol distance is 2 between the last two frames in each region, and the bit pattern similarity between the last two frames Lower. For example, the inter-code distance between SY (p-1) and SY (p) is 2, and for each combination of SY (q) and SY (q-1), SY (r) and SY (r-1). The inter-code distance for the bit pattern is also 2. Furthermore, SY (p−1) and SY (p) in the first region, SY (q) and SY (q−1) in the second region, SY (r) and SY (r−1) in the third region. ) To {SY (p-1), SY (p)}> {SY (q), SY (q-1)}> {SY (r), SY (r-1)} The similarity of the bit pattern is lowered between the last two frames indicating each region. Alternatively, the similarity between the last two frames for each region may be lowered by the difference in the number of inverted bits, and the inter-code distance may be set to 2 between the last two frames of each region. By arranging such an inter-code distance and the number of inverted bits as shown in FIG. 8, error frame propagation stays in each region, and furthermore, error frame propagation across the next sector can be prevented. The final number of frames in each area is not limited to 2 frames, but may be 1 frame, 3, 4,..., And the area divided for each p, q, r frame is limited to 3 areas. Instead, it may be two regions, or four, five,... Regions.

  Also in the fifth embodiment described above, in order to more accurately specify the frame position within one sector, the relationship between the inter-code distance and the number of inverted bits given to the bit pattern of the synchronization signal for the final number of frames dividing each area Furthermore, the relationship between the inter-code distance and the number of inverted bits given to each of the bit patterns of the synchronization signal for the final number of frames and the other frames for each region will be described.

  For the final number of frames that divide each region, the inter-code distance of the synchronization signal included in each final number frame is given 2 or more, and the bit patterns of different inverted bit numbers are given to the final number frames of each region. Alternatively, each region is divided without being limited to giving a bit pattern having a different inversion bit number to the synchronization signal included in each final number frame and giving a bit pattern having an inter-symbol distance 2 to each other. There are also cases where all the last few frames are given sync signal bit patterns whose inter-code distances are 2 or more or whose inversion bit numbers are all different.

In addition, with respect to the synchronization signals for the final number of frames and other frames other than that in each divided region, the similarity to the synchronization signal may be lowered depending on the combination of the intersymbol distance and the number of inverted bits. For example, the number of inverted bits is given so that {the synchronization signal included in the final number frame}> {the synchronization signal included in the other frame}, and {the synchronization signal included in the final number frame}, {the synchronization included in the other frame In the case of giving a bit pattern in which the inter-code distance is 2 or more in each signal}, or a bit pattern in which the number of inverted bits is different in each of {synchronization signal included in the final frame} and {synchronization signal included in other frames} And a bit pattern in which the intersymbol distance is 2 or more may be given between {the synchronization signal included in the last few frames} and {the synchronization signal included in other frames}.

  In addition, a bit pattern having an inter-symbol distance of 2 or more between each region, a bit pattern having a different number of inverted bits, and a bit pattern in which the similarity of each synchronization signal is lowered by combining them are given, and the similarity is lowered. There is also a case.

  Also, in each region, a bit pattern having an inter-symbol distance of 2 or more, a bit pattern having a different number of inverted bits, and a synchronization signal by combining them among all other frames other than the final number of frames to be divided. In some cases, a bit pattern having a low similarity is provided to reduce the similarity.

  In the present invention, a common synchronization pattern is used for the synchronization signal, and the type of the synchronization signal is determined by the connection bit and the identification bit. However, the present invention is not limited to this, and the inter-code distance with respect to the bit pattern included in the synchronization signal If the number of inversion bits or 2 is different, the common synchronization pattern may not be used. For example, in the second embodiment, the synchronization pattern included in SY7 indicating the last area of the sector and SY0 indicating the head of the sector is different from the synchronization pattern common to other SY1 to SY6, and SY7 is determined by the connection bit and the identification bit. , SY0 may be determined.

  The synchronization frame in the digital signal generation method of the present invention is recorded on a disk-shaped recording medium, and can be accessed and reproduced in units of sectors by detecting the sector ID. Furthermore, the disc-shaped recording medium that is the subject of synchronization frame recording is not limited to one in which all the synchronization frames from the beginning to the end of the recorded information are written continuously on the track, but the physical in the disc as pre-pits on the rewritable disc. The present invention can also be applied to an optical disc in which addresses are engraved, frames for one sector are continuously written between the prepits, and the sectors are discontinuous.

  Further, in the third, fourth, and fifth embodiments, there may be a case where the arrangement of SY0 to SY7 shown in the first and second embodiments corresponds to the synchronization frame constituting one sector. In the third, fourth, and fifth embodiments, only the positions of bit patterns in which the inter-code distance is 2 or the number of inverted bits are different are shown. For example, in the third embodiment, the synchronization signals of SY0 to SY7 Even when the arrangement is adapted, the same SY7 synchronization signal has a code-to-code distance of 2, and bit patterns having different inversion bit numbers are applied.

  Further, the inter-code distances of the mutual bit patterns of the synchronization signals described in the first to fifth embodiments are not limited to 2, but all are 2 or more, for example, the inter-code distance is 2 for a certain bit pattern. For other bit patterns, different combinations of inter-code distances such as inter-code distance 3 may be used.

  In addition, the synchronization signal having a bit pattern with a different inter-code distance 2 or inverted bit number described in the first to fifth embodiments is necessary in each embodiment even if the number of bits allocated to the synchronization signal is limited. For the purpose of satisfying different types of bit patterns, it is possible to reduce the degree of similarity between bit patterns by combining bit patterns having a distance between codes of 2 or more and bit patterns having different numbers of inverted bits. .

The figure which shows the 1st Example of the digital signal recording method by this invention. The figure which shows an example of the production | generation method of the digital signal recorded on a disk. The figure which shows the component and bit pattern of a synchronizing signal. The figure which shows the response | compatibility of the inversion bit number with respect to a synchronizing signal, and the synchronizing signal whose code | symbol distance is 1. The figure which shows the 2nd Example of the digital signal recording method by this invention. The figure which shows the 3rd Example of the digital signal recording method by this invention. The figure which shows the 4th Example of the digital signal recording method by this invention. The figure which shows the 5th Example of the digital signal recording method by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lead synchronizing signal, 2 ... Sector ID, 3 ... Connection, identification bit, 4 ... Common synchronous pattern, 5 ... Frame position, 6 ... Sector.

Claims (2)

A first frame having a synchronization signal including a bit pattern for identification and address information indicating a recording position on a recording medium; and a second frame having the synchronization signal and not having the address information. A digital signal recording method for recording a plurality of sectors configured in combination on a recording medium,
The synchronization signals are arranged one by one for one frame,
With respect to a plurality of even-numbered frames in the sector , a relationship of continuous synchronization signals arranged every k frames (k is an odd number of 9 or more) is as follows:
In a combination of bit patterns for every k frames of consecutive synchronization signals for identification, the inter-symbol distance is 2 or more, or
In a combination of bit patterns with respect to successive synchronization signals for identification, the number of inversion bits included is different,
Furthermore, the two synchronization signals immediately before the first frame are combinations having different numbers of inverted bits included in the bit pattern for identification. A first frame having a synchronization signal including a bit pattern for identification and address information indicating a recording position on a recording medium; and a second frame having the synchronization signal and not having the address information. An information recording medium on which a plurality of sectors configured in combination is recorded,
The synchronization signals are arranged one by one for one frame,
With respect to a plurality of even-numbered frames in the sector , a relationship of continuous synchronization signals arranged every k frames (k is an odd number of 9 or more) is as follows:
In a combination of bit patterns for every k frames of consecutive synchronization signals for identification, the inter-symbol distance is 2 or more, or
In a combination of bit patterns with respect to successive synchronization signals for identification, the number of inversion bits included is different,
Furthermore, the two synchronization signals immediately before the first frame are combinations having different numbers of inverted bits included in the bit pattern for identification.

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