JP4029085B2 - Recording medium, recording method and apparatus, and reproducing method and apparatus - Google Patents

Description

  The present invention relates to a recording medium, a recording method and apparatus, and a reproducing method and apparatus on which data in which synchronization codes having various control information are inserted are recorded.

  2. Description of the Related Art Conventionally, recording media such as magnetic disks and optical disks are recorded with redundant bits such as parity added to correct data reading errors that occur when written data is reproduced. Although error correction is performed on the reproduced data, in recent years, higher error correction capability has been required. One way to increase the error correction capability is to increase the number of redundant bits added to the data. However, adding many redundant bits to the data is disadvantageous because it causes a decrease in the recording density of the optical disk. As another method, as a method for improving the error correction capability without increasing the amount of error correction code, a method for increasing the amount of data serving as an error correction processing unit is conceivable. For example, a block composed of a plurality of sectors is set, and the block is set as an error correction processing unit.

  FIG. 18 is an explanatory diagram showing a data format of one block which is a conventional error correction processing unit.

  The block includes 32 sectors, an attribute row, and a parity part. Each section is composed of 4 rows, and each sector row is written with 129 code words indicated by D (i, 0) to D (i, 128), and each code word D (i, j) is It corresponds to 1 byte of data, and 16 parity codewords P (i, 0) to P (i, 15) correspond to bytes of data. Here, i represents the number of rows in the data block. Rows 0-3 are assigned to the first sector, rows 4-7 are assigned to the second sector,..., Rows 124-127 are assigned to the 32nd sector. As a result, each sector has a capacity of 516 bytes, and a 4-byte CRC code can be written in addition to 512-byte user data.

  In the 128th row, the attribute of this block and each sector in this block is recorded by D (128,0) to D (128,128). Also in the 128th row, parities P (128,0) to P (128,15) are added to D (128,0) to D (128,128).

  Thereby, in the column direction, data D (0, j) to D (128, j) of 129 code words (where 0 ≦ j ≦ 128) and parities P (0, k) to P (128 of 129 code words are used. , K) (where 0 ≦ k ≦ 15).

  The parity part has 16 codeword parities Q (0, j) to Q (15, i) for the data D (0, j) to D (18, j) arranged in the column direction. Similarly, for the parities P (0, k) to P (128, k) arranged in the column direction, parities Q (0, m) to Q (15, m) of 16 codewords (where 129 ≦ m ≦ 144) is written.

The block in which the code word and the parity are arranged as described above is assigned an address for each block and is recorded at a predetermined position on the recording medium.
U.S. Pat. No. 4,728,929

  However, the conventional block only has an address at the beginning of the block, and no address is assigned to each sector. Therefore, the larger the block, the longer it takes to access and search. It was.

  Specifically, if you start reading data from the middle of a block, you cannot identify which position in which block the data starts to be read, so you must always start reading data from the beginning of the block. In addition, when accessing the target block, there is a disadvantage that it is necessary to wait until the head address of the block is identified.

  In addition, since the address cannot be determined unless reading is started from the head of the block, there is a disadvantage that it takes a long time to read the address when the block becomes large, and it takes a long time to search.

  On the other hand, for example, a method of assigning a frame number to each frame is also conceivable, but a code word becomes long to represent the number of all frames, and this code word is added to each frame. As a result, the recording density on the recording medium is reduced. Also, this frame number cannot be given other functions, which is inconvenient.

The present invention has been made in view of the above problems, and mainly provides a recording medium in which a multifunctional synchronization code that enables a data structure with high error correction capability without degrading recording density is devised. It is aimed.
Another object of the present invention is to provide a novel method for recording and reproducing data including the devised synchronization code.

In order to achieve the above object, a recording medium according to the present invention is a product that is a recording medium on which a channel signal that can be read by a player is written, and can be written to the product and read by a player. The channel signal is
A synchronization code arranged along the track at a certain interval;
A data code consisting of a code word sequence, arranged at the interval,
The synchronization code has an identification code having a predetermined pattern that can be distinguished from any data of the data code, and a type information code representing the type of the synchronization code,
The channel signal is a product that is a recording medium generated by a sequence of a synchronization code and a data code.

A recording method according to the present invention is a method in which a plurality of codewords form a frame, a plurality of frames form a data block, and a codeword string is recorded on a recording medium,
(A) Insert a synchronization code at a predetermined head position of the data block;
(B) giving each synchronization code an identification code for distinguishing the synchronization code of the data block from other codes;
(C) Based on the position of the block in which the synchronization code is inserted, type information for indicating the type of the synchronization code is added to each synchronization code,
(D) generating a channel signal from the data block in which the synchronization code is inserted;
(E) A recording method comprising a step of recording the channel signal.

A recording apparatus according to the present invention is a recording apparatus that records a channel signal generated by a codeword string on a recording medium, wherein a plurality of codewords form a frame, a plurality of frames form a data block,
Inserting means for inserting a synchronization code at a predetermined head position of the data block;
First assigning means for giving each synchronization code an identification code for distinguishing the synchronization code of the data block from other codes;
Based on the position of the block in which the synchronization code is inserted, second giving means for giving each synchronization code type information for indicating the type of the synchronization code;
A recording apparatus comprising output means for outputting a channel signal generated in the form of a data block in which a synchronization code is inserted for recording on a recording medium.

A reproduction method according to the present invention is a reproduction method for reproducing information from a recording medium, and the recording medium includes a synchronization code arranged along a track at a certain interval, and a code arranged at the interval. A data code consisting of a word string is recorded, and the synchronization code includes an identification code having a predetermined pattern that can be distinguished from any data of the data code, and a type for specifying the position of the synchronization code in the data block In a reproduction method for reproducing the information code,
(A) detecting the synchronization code by detecting the identification code;
(B) A reproduction method characterized by reading the type information in the synchronization code in order to identify the position of the synchronization code and to identify the data code following the synchronization code in the data block.

A playback device according to the present invention is a playback device for playing back information from a recording medium,
On the recording medium, a synchronization code arranged along a track with a certain interval and a data code composed of a code word string arranged at the interval are recorded. In a playback apparatus that has an identification code having a predetermined pattern that can be distinguished from the data of the above, and a type information code that specifies the position of the synchronization code in the data block, and reproduces these,
Means for detecting a synchronization code by detecting the identification code;
The reproducing apparatus comprises reading means for reading the type information in the synchronization code in order to determine the position of the synchronization code and specify the data code following the synchronization code in the data block.

In the recording medium according to the present invention, the synchronization code includes an identification code for identifying the synchronization code and other information, and a type code that is arranged immediately after the identification code and indicates the type of the synchronization code.
Therefore, according to the present invention, by detecting the identification code indicating the synchronization code, the synchronization code in the information recorded on the recording medium can be identified and frame synchronization can be achieved, and immediately after the identification code. A recording medium on which a codeword sequence with a synchronization code is recorded, which can be obtained by reading the type code arranged in the information, which is information represented by the type of the synchronization code and that represents information other than the synchronization code Can be provided.

According to a first aspect of the present invention, in the recording medium according to the present invention, the type code is a code indicating a position of the synchronization code in a block composed of a predetermined number of frames.
Therefore, according to the first aspect, it is possible to provide a recording medium on which a codeword sequence with a synchronization code that can know the position in the block of the synchronization code by reading the type code is recorded. .

According to the second aspect of the present invention, in the recording medium according to the first aspect,
The identification code includes a specific pattern that does not exist in the codeword sequence, and any codeword included in the codeword group is obtained by combining a portion subsequent to a predetermined portion of the identification code and the type code. It is formed.
Therefore, according to the second aspect, the synchronization code can be identified as a codeword sequence other than the synchronization code by the specific pattern of the identification code, and includes the information represented by the type code and the type code. If the information represented by the code word formed in the above is stored in association with each other, a special configuration for reading the type code is not required, and the code word formed including the type code is the code word. Provided is a recording medium on which a codeword sequence with a synchronization code into which such a synchronization code is inserted is recorded, which can be read as one of the group and know the position in the block of the synchronization code represented by the type code can do.

According to the third aspect of the present invention, in the recording medium according to the first aspect,
As the type code, a combination that minimizes the magnitude of the bias of the DC component of other information before and after the synchronization code is selected from a plurality of type codes representing the same type.
Therefore, according to the third aspect, by reading the type code, it is possible to know the position in the block of the synchronous code, and to detect the bias of the DC component of the reproduction signal reproduced from the recording medium of the present invention. It is possible to provide a recording medium on which a codeword sequence with a synchronization code in which a synchronization code selected so as to be smaller is inserted is recorded.

According to the fourth aspect of the present invention, in the recording medium according to the first aspect,
The block is divided into a plurality of sectors composed of a plurality of frames, and a frame at a predetermined position in each sector includes information indicating the address of the sector, and a synchronization code inserted before this frame. Includes a type code indicating that the frame includes address information.
Therefore, according to the fourth aspect, since the frame including the address information of the sector can be easily known from the type code of the synchronization code, by reading only the type information and the address information in the synchronization code. A record in which a codeword sequence with a synchronization code is recorded so that a search for reading out a desired block can be performed at a high speed and a codeword sequence with a synchronization code can be read out from the middle of the desired block. A medium can be provided.

According to the fifth aspect of the present invention, the block head identification step identifies the head part of the block composed of the plurality of frames. The synchronization code insertion position identification step identifies a position in the block where the synchronization code is to be inserted. In the identification code insertion step, an identification code for identifying the synchronization code and other information is inserted into the identified synchronization code insertion position. The type determination step determines the type of the synchronization code corresponding to the identified synchronization code insertion position. In the type code insertion step, a type code representing the determined type is inserted immediately after the identification code. In the recording step, the block in which the identification code and the type code are inserted is recorded in a continuous area of the recording medium.
Therefore, according to the fifth aspect, the identification code indicates that the synchronization code is different from the codeword sequence other than the synchronization code, and the information corresponding to the synchronization code insertion position by the type code indicating the type of the synchronization code. Thus, it is possible to provide a recording method for recording on a recording medium a codeword sequence with a synchronization code in which a synchronization code that can represent information other than the synchronization code is inserted.

According to a sixth aspect of the present invention, in the recording method according to the fifth aspect, the identification code generation step further includes a step of identifying the codeword sequence representing other information after identifying the synchronization code insertion position. An identification code including a specific pattern that does not exist is generated. The type code generation step includes any of those included in the codeword group by combining the part after the predetermined part of the generated identification code after the type determination of the synchronization code and the type code representing the determined type. The type code is generated so that the codewords are formed. The recording step records the generated type code.
Therefore, according to the sixth aspect, according to the specific pattern of the identification code, the synchronization code can be identified as a codeword sequence other than the synchronization code, and the information represented by the type code and the type code are included. If the information represented by the code word formed in the above is stored in association with each other, a special configuration for reading the type code is not required, and the code word formed including the type code is the code word. Recording method for recording on a recording medium a codeword sequence with a synchronization code into which the synchronization code is inserted, which can be read as one of the group and know the position in the block of the synchronization code represented by the type code Can be provided.

According to a seventh aspect of the present invention, in the recording method according to the fifth aspect, the direct current component calculation step further includes a predetermined step before and after the synchronization code is inserted after the synchronization code insertion position is identified. In the information other than the synchronization code in the interval, the magnitude of the bias of the DC component of the information is calculated. The type code selection step selects a type code that minimizes the calculated magnitude of the bias of the DC component from a plurality of type codes representing the same type among the determined types. The type code recording step records the selected type code.
Therefore, according to the seventh aspect, by reading the type code, it is possible to know the position in the block of the synchronous code, and to detect the bias of the DC component of the reproduction signal reproduced from the recording medium of the present invention. It is possible to provide a recording method for recording on a recording medium a codeword sequence with a synchronization code in which a synchronization code selected so as to be smaller is inserted.

According to an eighth aspect of the present invention, in the recording method according to the fifth aspect, the address frame identification step further includes the step of identifying the address frame in the block divided into a plurality of sectors composed of a plurality of frames. A frame at a predetermined position in each sector and including information indicating the sector address is identified. The type code insertion step inserts a type code indicating that the frame includes address information immediately before the frame including the address information and immediately after the identification code.
Therefore, according to the eighth aspect, since the frame including the address information of the sector can be easily known from the type code of the synchronization code, by reading only the type information and the address information in the synchronization code. In addition, a codeword sequence with a synchronization code can be recorded on a recording medium so that a search for reading a desired block can be performed at a high speed and a codeword sequence with a synchronization code can be read from the middle of the desired block. A recording method can be provided.

According to the ninth aspect of the present invention, in the reproduction method, the synchronization code identifying step identifies the synchronization code in the information recorded on the recording medium of the first view by detecting the identification code. The codeword synchronization step synchronizes the read clock with the codeword based on the identified synchronization code. In the type reading step, the type code of the synchronous code is read based on the reading clock synchronized with the code word. The information position specifying step specifies the position in the block of the information recorded immediately after the synchronization code from the read type code.
Therefore, according to the ninth aspect, it is possible to accurately identify the synchronization code from the codeword sequence with the synchronization code recorded on the recording medium of the first view and synchronize the read clock with the codeword. It is possible to provide a reproduction method capable of selectively reading information recorded immediately after the synchronization code by specifying the position of the information recorded immediately after the synchronization code in the block. it can.

According to the tenth aspect of the present invention, the synchronization code identification step detects an identification code including a specific pattern that does not exist in the codeword sequence representing other information from the recording medium according to the second aspect. Thus, the synchronization code is identified. The codeword synchronization step synchronizes the read clock with the codeword based on the identified synchronization code. The type reading step reads the type code as a code word based on a read clock synchronized with the code word. In the type decoding step, the read type code is regarded as a code word and decoded, and type information is extracted. The information position specifying step specifies the position in the block of the information recorded immediately after the synchronization code from the extracted type information.
Therefore, according to the tenth aspect, the synchronization code can be accurately identified and the read clock can be synchronized with the code word by the specific pattern of the identification code, and the code formed including the type code Read a word as one of the codeword groups and selectively read the information recorded immediately after the synchronization code by specifying the position of the information recorded immediately after the synchronization code in the block It is possible to provide a reproduction method that can

According to the eleventh aspect of the present invention, in the reproduction method, the synchronization code identifying step identifies the synchronization code in the recorded information from the recording medium according to the fourth aspect by detecting the identification code. The codeword synchronization step synchronizes the read clock with the codeword based on the identified synchronization code. In the type reading step, the type code of the synchronous code is read based on the reading clock synchronized with the code word. The information position specifying step specifies the position in the block of the information recorded immediately after the synchronization code from the read type code. In the address recognition step, when the position of the frame including the address information is specified by the information position specifying step, the information of the predetermined position in the frame is recognized as the address information.
Therefore, according to the eleventh view, since the frame including the address information can be easily known from the recording medium of the fourth view by the type code of the synchronous code, the type information and the address in the synchronous code can be obtained. To provide a reproduction method capable of performing a search for reading a desired block at a high speed by reading only information, and reading a codeword sequence with a synchronous code from the middle of the desired block. it can.

  This application is based on a Japanese patent application filed on April 4, 1995, Japanese Patent Application No. 7-78988, and all the contents of this basic application constitute part of the contents of this application. And

  According to the present invention, by detecting an identification code representing a synchronization code, it is possible to identify the synchronization code in the information recorded on the recording medium and obtain frame synchronization, and to place the code immediately after the identification code. Provides a recording medium on which a codeword sequence with a synchronization code is recorded, which can be obtained by reading the type code, and can be obtained as information that is represented by the type of the synchronization code and that is not a synchronization code There is an effect that can be done.

Example 1
FIG. 1 is a configuration diagram showing data with a synchronization code as data before modulation written in the recording medium of the present embodiment.
On the optical disk, a data amount of 168 × 168 bytes excluding the synchronization code is written as one block (one unit of error correction processing). FIG. 1 is a conceptual diagram showing a configuration in which the data for one block is virtually arranged in two dimensions.

  Each row of the two-dimensional array constituting the block is defined in the same format, and the synchronization code (2 bytes), the first frame data (84 bytes), another kind of synchronization code (2 bytes), and the second frame data. (84 bytes) is written. Each row is followed by a synchronization code S1, S2 or S3 followed by the data D1, 1, D2, 1,..., D156,1 written in the first data frame. Further, the synchronization code S4 is followed by the data D1,2, D2,2,..., D156,2 written in the second data frame. Each of the second frames includes a 10-byte parity Pr corresponding to the data of two frames written in the row at the end.

  In the example shown in FIG. 1, the block is composed of 12 sectors SEC1 to SEC12 with 14 rows as one sector. In the first frame following the synchronization code S1 or S2 of each sector, the address of the sector is written.

  The synchronization code S1 is provided immediately before the first frame in the first section SEC1 of the block, and indicates the beginning of the block. The synchronization code S2 is provided immediately before the first frame corresponding to the head of each sector other than the head of the block, and indicates the head of the sector. The synchronization code S3 is provided immediately before the first frame of the 2nd to 14th rows of each sector, and indicates the beginning of a row other than the block and the sector head. The synchronization code S4 is provided immediately before the second frame of all rows and indicates the middle of each row.

  Note that the 14th row of each sector is the parity row Pc of that column. The parity of 12 bytes generated for the 156 bytes (12 x 13 = 156 because there are 12 bytes in each row) collected in the column direction from the data written in the 1st to 13th rows of each sector One byte is arranged in the corresponding column of the rows Pc1 to Pc24. Seven 12-byte parities are written in parity rows Pc1 to Pc24 (14th row) of the corresponding column for each byte. The parity row distributed in the 14th row of each sector is used for error correction processing after all the data of one block has been read.

  The block configured as described above is converted into a code word by 8-15 conversion described later, and a channel signal is generated by NRZI modulation, and then written on a recording medium such as an optical disk. At this time, the identification units of the synchronization codes S1 to S4 are converted into a code string that does not appear (that is, is not recorded) in the data according to the encoding rule of 8-15 conversion.

2 and 3 are conversion tables showing conversion examples of the 8-15 conversion in the present embodiment.
As shown in FIGS. 2 and 3, in the 8-15 conversion of this embodiment, at least one code word represented by a 15-bit pattern is associated with 8 bits (1 byte) of data. In the tables shown in FIGS. 2 and 3, the MSB (most significant bit) of a 15-bit pattern is used as a combined bit for directly connecting codewords. All combined bits are indicated by “0”, but can be changed to “1” by DC control. Details of the DC control are disclosed in US Pat. No. 4,728,929 (S. Tanaka) issued on Mar. 1, 1988, which includes a part of the contents of the present application. Shall be made.

  The number of code words to be converted by the 8-15 conversion is 13 (or 12) at the maximum with “0” sandwiched between “1” in one code word, and 2 at the minimum. It is determined to be. That is, in terms of the inversion interval of the NRZI channel signal corresponding to the codeword, when the length of one bit of the codeword is T, the maximum inversion interval Tmax = 14T (or 13T) and the minimum inversion interval Tmin = 3T. Determined. In addition, in the codeword combination part, the number of consecutive “0” s sandwiched between “1” s in the codeword string obtained by combining these codewords is controlled so as to satisfy the maximum value and the minimum value. .

FIG. 4 is an explanatory diagram showing the data structure of the synchronization codes S1 to S4 of the present embodiment. In FIG. 4, “X” represents “0” or “1”.
The synchronization codes S1 to S4 have a data length of 2 bytes and are represented by a 30-bit code string. Each of the synchronization codes includes an identification unit for identifying the synchronization code and other data, and type information indicating the position in the block where the synchronization code is inserted.

  The identification unit is expressed by the inversion interval TS = Tmax + 2T (or Tmax + 3T) = 16T in the case of a code string having 15 consecutive “0” s sandwiched between “1” s, that is, a channel signal after NRZI modulation. Is done. This is a code string that represents data other than the synchronization code and a code string that does not appear in the channel signal after NRZI modulation corresponding thereto and an inversion interval.

The type information is represented by 5 bits from the 22nd bit to the 26th bit of the synchronization code. Further, except for the type information, a fixed part in which a common code is defined for all synchronous codes. The fixed part is determined so as to satisfy the coding rule of 8-15 conversion in a joint part between a synchronous code and data other than the synchronous code.
Needless to say, an 8-16 conversion can be used instead of the 8-15 conversion.

The code string of the latter half 15 bits of the synchronization code is a code word part selected so as to be a code string existing as a code word by 8-15 conversion. Since the type information is 5-bit information, in a method of reading a 15-bit code word as a minimum unit of data as in reading data other than a synchronous code, only the type information is read as data. Can not. Therefore, when the code string of the latter half 15 bits of the synchronization code is used as the code word part, when the signal reproduced from the recording medium is subjected to 8-15 reverse conversion, the code word part including the type information is changed to other data. Can be read in the same way.
Needless to say, an 8-16 conversion can be used instead of the 8-15 conversion.

  When the NRZI channel signal shown in FIG. 7C is recorded on an optical disk or another recording medium, pits or marks are formed along the track of the disk corresponding to the high of the NRZI channel signal, and the low of the NRZI channel signal. Corresponding to, non-pits or non-marks are formed. Since the pits and marks are formed by, for example, laser light, it is necessary to limit the continuous length of such pits and marks and the length at which such pits and marks are intermittent. If the mark or mark interval becomes abnormally long, the stability of the PLL control necessary for generating the read clock is lost, and the reconstructed output from the high-pass filter varies greatly. On the other hand, if the laser beam becomes abnormally short, no pits or marks are formed on the disk, or even if they are formed, they become abnormally small.

  For these reasons, in the present invention, the pit or mark for data (for example, video or audio data) has the longest pit or mark length Tmax set to 14T (or 13T), while the identification unit in the synchronous code The length TS of the special pit or special mark used in the above is Tmax + nT. Here, n is an integer equal to or greater than 2, and T is a unit length corresponding to 1 bit of the binarized code. In some embodiments, n = 2, and in other embodiments, n = 3. Thus, by selecting the length of the pit or mark in the identification unit to be longer than any pit or mark of data other than the synchronization code, the identification unit can be distinguished from such data.

In the present invention, the minimum length Tmin of pits and marks used in data and synchronous codes is set to T3.
FIG. 5 is an explanatory diagram showing the relationship between the reproduction signal reproduced from the optical disk of the present embodiment and the NRZI channel signal read from the reproduction signal. FIG. 5 (a) shows the reproduced signal and its read threshold value VC reproduced corresponding to the identification part of the synchronization code. FIG. 5B shows a read clock given by the pit interval T. FIG. 5 (c) shows the output signal of the converter to which the reproduction signal and the read threshold value VC = V0 are input. FIG. 5 (d) shows an NRZI channel signal obtained by sampling the output signal of the comparator shown in FIG. 5 (c) with the read clock shown in FIG. 5 (b). FIG. 5 (e) shows the output signal of the comparator that receives the reproduction signal and the read threshold value VC = V0 + ΔV exceeding the allowable range. FIG. 5 (f) shows an NRZI channel signal obtained by sampling the output signal of the comparator shown in FIG. 5 (e) with the read clock shown in FIG. 5 (b). Note that the output signal of the comparator is inverted to a high level at the intersection of the reproduction signal and the reading threshold value VC, and the NRZI channel signal shown in FIG. 5D is inverted from a low level to a high level. Let time be t0.

  A reproduction signal reproduced from the recording medium is obtained as an analog signal as shown in FIG. For this reason, the reproduction signal is digitized by the comparator with a value equal to or higher than the reading threshold VC as a high level and a value lower than the reading threshold VC as a low level. The digitized contrast output signal is sampled at the timing of the read clock shown in FIG. 5B, whereby the NRZI channel signal shown in FIGS. 5D and 5F is reproduced. Further, the phase of the read clock and the read threshold value are controlled so that the comparator output signal is inverted with the intermediate position between the clocks as a reference position. However, when the reading threshold value VC is not stable, for example, at the start of reading the reproduction signal, the reading threshold value VC varies as shown in FIG.

  If the NRZI channel signal shown in FIG. 5D is a correct reading result, the permissible range (VCmin, VCmax) of the reading threshold value VC for correctly reproducing the NRZI channel signal, that is, NRZI. The range in which no error occurs in reading the channel signal is represented by a deviation ΔT from the reference position at which the comparator output signal is inverted. That is, as shown from the time (t0-T) to the time t0 in FIG. 5A, the fluctuation VCmin ≦ VC ≦ VCmax of the reading threshold value VC within the allowable range is the reference position of the inversion timing of the converter output signal. Deviation from-(T / 2) <ΔT ≦ (T / 2).

  As shown in FIG. 5C, from time (t0 + 15T) to time (t0 + 16T), the inversion timing of the comparator output signal is within the allowable range of − (T / 2) <ΔT ≦ (T / 2). There is a deviation of ΔT from the position. Therefore, a correct sampling value is obtained with the clock at time (t0 + 16T).

  However, the deviation ΔT from the reference position of the inversion timing of the comparator output signal exceeds the allowable range represented by − (T / 2) <ΔT ≦ (T / 2) due to the fluctuation of the reading threshold value VC. In such a case, the inversion interval is shifted by ± T at the rise of the NRZI channel signal and − (± T) at the fall of the NRZI channel signal.

  Due to the relative fluctuation of the read threshold value VC due to noise with respect to the reproduction signal, the inversion position of the NRZI channel signal representing the synchronization code and data is shifted by 1 bit when the allowable range is temporarily exceeded. There is. That is, the position of “1” in the code string of the code word string is shifted by 1 bit to the adjacent code bit. There is a high possibility that the data read error caused by this can be correctly corrected by the error correction processing. In other words, the optical disk reproducing apparatus cannot be put into practical use unless it is designed with a margin that makes it possible to correct such a 1-bit shift of the inversion position caused by noise. Therefore, depending on the noise, the reversal interval of the reproduced NRZI channel signal may hardly be shifted by 2T or more.

  In this case, the maximum inversion interval Tmax = 14T in the NRZI channel signal representing data other than the synchronization code may be read as 13T or 15T, but is rarely read as 12T or 16T. Further, the synchronization code identification section TS = 16T may also be read as 15T or 17T. In this case, since the signal portion that inverts with an inversion interval of 16T or more does not appear in the NRZI channel signal representing data other than the synchronization code, the signal portion with the inversion interval of 16T or more is the identification portion of the synchronization code. By determining, data other than the synchronization code and the synchronization code can be correctly identified. At this time, the inversion period 15T and the identification unit of the read synchronization signal are invalidated. In this case, the invalidated synchronization code is judged based on the periodicity in which the synchronization code appears in the NRZI channel signal. Is controlled so as not to be read as data other than the synchronization code.

  However, for example, when the fluctuation of the read threshold value VC exceeding the allowable range continues at VC = V0 + ΔV as shown by a two-dot chain line in FIG. As shown in FIG. 5B, inversion portions of the NRZI channel signal at both ends of the identification portion of the synchronization code cause a reading error of the inversion interval T and also occur in a data portion following the synchronization code. In such a case, by determining that a signal portion having an inversion interval of 16T or more that does not appear in data other than the synchronization code is an identification portion of the synchronization code, synchronization is disturbed and data cannot be read. However, in such a case, even if the synchronization is not disturbed, it is unlikely that the data reading error caused by this can be correctly corrected by the error correction processing. As described above, when the optical disk reproducing apparatus detects a large number of signal portions whose inversion interval is 18T or more, it detects a data reading abnormality and performs processing corresponding thereto.

  As described above, by setting the inversion interval TS of the identification part of the synchronization code to the length of TS = Tmax + 2T, the synchronization code and other data are accurately identified within a range where data can be read. be able to. In addition, by setting the inversion interval TS of the identification part of the synchronization code to the length of TS = Tmax + 2T, the length of the identification part of the synchronization code is shortened compared to the case where TS = 2Tmax as in the conventional synchronization code. Accordingly, the type information for adding various functions to the synchronization code can be included. Furthermore, this allows the length of the entire synchronization code to be set to twice the length of the codeword, so that the first half of the synchronization code and the codeword representing the data other than the synchronization code are The latter half can be classified, and the type information of the latter half can be read in the same manner as a code word representing data other than the synchronization code.

FIG. 6 is a table showing the type information of the synchronization code of this embodiment and the read value of the code word portion corresponding to the type information.
Each of the synchronization codes S1 to S4 indicates the position in the block in which the synchronization code is inserted by the 5-bit type information from the 22nd bit to the 26th bit of the synchronization code shown in FIG. The synchronization code S1 indicates that the synchronization code S1 is inserted at the head of the block by the type information 1 “10010” or the type information 2 “00010”. Similarly, the synchronization code S2 indicates that the synchronization code S2 is inserted at the head of a section other than the head of the block by the type information 1 “01001” or the type information 2 “01000”. The synchronization code S3 indicates that the synchronization information S3 is inserted at the beginning of a line other than the beginning of the block and the beginning of the sector by the type information 1 “10001” or the type information 2 “10000”. The synchronization code S4 indicates that the synchronization code S4 is inserted at the head of the frame located in the middle of each row by the type information 1 “00000” or the type information 2 “00001”.

  Also, as shown in FIG. 6, the various types of information are read in units of code word parts including the information. For example, the type information 1 “10010” of the synchronization code S1 is inserted into 5 bits from the 22nd bit to the 26th bit of the synchronization code shown in FIG. Therefore, the code pattern of the synchronous code S1 having the type information 1 “10010” is “00100000000000000000000100100100010”, and the code word part of the synchronous code S1 is “000100100100010”. Accordingly, the code word portion of the synchronous code S1 having the type information 1 “10010” is read as “114” as in the 8-15 conversion table shown in FIG. Similarly, the code word portion of the synchronous code S1 having the type information 2 “00010” is read as “86”. If the code word read immediately after identifying the identification part of the synchronization code is “114” or “86”, it is found that the identified synchronization code is the synchronization code S1 inserted at the head of the block. In the same manner, synchronization codes having other types can be identified.

  The type information 1 and the type information 2 are information indicating the same synchronization code insertion position, but the type information 1 has an even number of “1” s included in 5 bits of the type information, and the type information 2 is It is an odd number.

  FIG. 7 is an explanatory diagram illustrating a method for selecting the type information 1 or the type information 2 in the synchronization code of this embodiment. Although FIG. 7 illustrates the selection method of the type information 1 or type information 2 of the synchronization code S4, the type information 1 or the type information 2 is selected similarly for the other synchronization codes S1 to S3. Further, the synchronization code S4 is inserted between the frames 1 and 2, as shown in FIG.

  FIG. 7A shows a code pattern common to all synchronous codes. FIG. 7B shows a change in DSV (Digital Sum Variation) when the type information 1 is selected as the type information of the synchronization code S4. FIG. 7C shows a change in DSV when the type information 2 is selected as the type information of the synchronization code S4. The DSV is a value calculated by adding “+1” per unit time if the waveform of the NRZI channel signal is high level, and “−1” if the waveform of the NRZI channel signal is low level. Represents the bias. The DSV is a value that is cumulatively added from a predetermined position of data to be recorded, for example, the head of data to be recorded or the head of a block.

  As shown in FIG. 1, the synchronization code S4 is inserted between the first frame and the second frame. In order to determine which type information 1 or type information 2 is appropriate as the type information of the synchronization code S4, from the beginning of the data to be recorded to the end of the first frame at the position immediately before the synchronization code S4 , DSV values are cumulatively added. At the time Tx (FIG. 7), the level of the NRZI channel signal and the DSV value are recorded in the DSV memory. In the case shown in FIG. 7, high and d = 12 are recorded in the DSV memory. The DSV value d1 is calculated at the point where the DSV of the frame 2 is compared. At this time, the type information 1 (00000) of the synchronization code S4 is used. Next, the type information 2 (00001) is used instead of the type information 1, and the DSV value d2 is calculated at the point where the DSV of the frame 2 is compared. The calculated DSV values d1 and d2 are compared, and the type information whose DSV absolute value is smaller at a predetermined DSV comparison position in the second frame of frame 2 is selected.

  The DSV value up to the first 5 bits of the second frame, type information 1 indicates “4” as shown in FIG. 7B, and type information 2 indicates “6” as shown in FIG. 7C. Yes. This DSV is further calculated up to a predetermined DSV comparison position in the second frame, the absolute value of the DSV at the DSV comparison position is compared, and the type information with the smaller absolute value is selected. Thereby, when writing on the recording medium in the format shown in FIG. 1, it is possible to suppress the bias of the direct current component generated in the reproduction signal. Furthermore, as is generally done, compared to the case where the bias of the DC component is suppressed by inserting a code string separately into the data, the bias of the DC component is represented by the type information indicating the type of the synchronization code. Therefore, it is possible to reduce the amount of code strings to be inserted in order to suppress the bias of the DC component, and to effectively use the storage area of the recording medium.

  As described above, the head of the block can be easily identified by the synchronization code S1, and error correction processing with high correction capability can be performed using one block of data as a unit for error correction.

  Further, the position of the frame 1 where each sector address in the block is written can be easily identified by the synchronization code S2. As a result, for example, when the target block is accessed, even if the reading starts from the middle of the target block, the sector address following the synchronization code S2 immediately after is read, so that the last of the target block is read from that sector. The data up to the sector is temporarily extracted on the memory, and then the remaining sector is extracted from the head of the target block and is replenished before the data extracted on the memory to read out the data of the target block in a short time. be able to.

  In addition, since the position of the frame in which the sector address is written can be easily identified, a desired track can be accessed while reading only the address, and a search operation can be performed at high speed.

  In addition, with the synchronization codes S1 to S4, it is possible to identify the first bit of the code word for each frame and correct the bit shift of the reproduced data with respect to a bit drop such as dropout that occurs during data reproduction. it can.

  In the present embodiment, the signal portion in which the inversion interval of the corresponding NRZI channel signal is TS = (Tmax + 2T) is used as the identification unit of the synchronization code. For example, the NRZI channel signal corresponding to the synchronization code is used as the identification unit. A signal portion in which the inversion interval is TS = (Tmax + 3T) may be used. In this case, even if the reading threshold value VC temporarily fluctuates beyond the allowable range, and a deviation of ± T occurs in part of the read NRZI channel signal, data other than the synchronization code NRZI channel signal reading maximum inversion interval Tmax ′ representing

Tmax−T ≦ Tmax ′ ≦ Tmax + T
The inversion interval TS ′ of the NRZI channel signal read corresponding to the identification part of the synchronization code is
Tmax + 2T ≦ TS ′ ≦ Tmax + 4T
It becomes.

  The inversion interval TS of the NRZI channel signal corresponding to the identification part of the synchronization code may represent the length of pits or marks formed on the disk, and conversely, the length of such pits or mark intervals. It may represent. In the present invention, the pit length TS of the identification portion is set to (Tmax + 2T) or more, but most preferably, it is set to (Tmax + 3T) as described below.

  Writing or reading pits or marks on the disc (hereinafter simply referred to as marks, but not only including pits and marks but also including other projections) (hereinafter, only described in the case of reading) However, the mark length Tmax may be erroneously read as (Tmax ± T).

  If the mark length TS of the identification part is selected as (Tmax + 2T), this mark may be erroneously read as (Tmax + 2T) ± T, that is, (Tmax + T) or (Tmax + 3T). Similarly, the maximum data mark length Tmax may be erroneously read as (Tmax + T), that is, (Tmax−T) or (Tmax + T). In this case, if not only (Tmax + 2T) but also (Tmax + 3T) are included as valid, the mark length of the identification unit is higher than when only (Tmax + 2T) is effective. With reliability, it is possible to distinguish between the mark of the identification unit and the mark with the maximum length in the data. In this case, however, the identification section erroneously read as (Tmax + T) cannot be distinguished from the case where the maximum length mark in the data is erroneously read as (Tmax + T), and must be ignored.

  On the other hand, if the mark length TS of the identification part is selected as (Tmax + 3T), this mark may be erroneously read as (Tmax + 3T) ± T, that is, (Tmax + 2T) or (Tmax + 4T). Similarly, the maximum data mark length Tmax may be erroneously read as (Tmax ± T), that is, (Tmax−T) or (Tmax + T). In this case, if not only (Tmax + 2T) but also (Tmax + 3T) and (Tmax + 4T) are included as effective, the distinction between the mark of the identification unit and the maximum mark of the data becomes more reliable. Therefore, if the mark length TS of the identification part is set to (Tmax + 3T) instead of (Tmax + 2T), it becomes possible to distinguish the mark of the identification part and the maximum data mark with a higher probability. By determining that the signal portion in which the inversion interval of the read NRZI channel signal is equal to or greater than (Tmax + 2T) is the identification portion of the synchronization code, data other than the synchronization code and the synchronization code can be correctly identified, All synchronization codes can be correctly identified. The number of invalid synchronization codes is reduced, almost all synchronization codes are correctly identified, and the start point of the frame can be identified. Therefore, even if a data bit is shifted due to a loss of a bit caused by a dropout of a signal generated at the time of reproduction, it is possible to correct correctly. In addition, when the fluctuation of the reading threshold value VC exceeding the allowable range continues, a data reading abnormality is detected by detecting a signal portion where the inversion interval of the NRZI channel signal is equal to or greater than (Tmax + 5T). Can do.

  Note that the 5-bit type information is not limited to the correspondence between the bit pattern and the type content, and the type information 1 and the type information 2 include an odd number of “1” s included in the 5-bit pattern. Any combination of patterns and even patterns may be selected as long as the codeword part of the synchronization code including the type information is selected to exist in the codeword pattern. The type information may be arranged in front of the identification unit.

  In the above method for selecting the type information, the synchronization code having the type information 1 corresponding to the type of the synchronization code is added to the DSV value cumulatively added from the beginning of the data to be recorded to immediately before the synchronization code. DSV at a predetermined position of a frame following the synchronization code when the synchronization code is inserted, and a DSV at a predetermined position of the frame following the synchronization code when the synchronization code having the type information 2 corresponding to the type of the synchronization code is inserted And the type information for which the absolute value of the DSV at the predetermined position of the frame following the synchronization code is smaller is selected, but the DSV calculation range serving as a reference for selecting the type information is: It is not limited to the said range.

  Specifically, for example, the DSV cumulatively added from the beginning of the block (or from the beginning of the frame immediately before the synchronization code or from a predetermined position of the frame immediately before the synchronization code) to immediately before the synchronization code. The value of DSV up to a predetermined position of the frame following the synchronization code when the synchronization code including the type information 1 or the type information 2 is inserted is calculated for both the type information 1 and the type information 2 Then, the type information with the smaller absolute value of the DSV up to a predetermined position in the frame following the synchronization code may be selected.

  18 and 19 show an optical disk on which an NRZI channel signal is recorded according to the present invention. The optical disk shown in FIG. 18 is a writable disk RD (CAV), and the optical disk shown in FIG. 19 is a non-writable disk ND (CLV), that is, a read-only disk.

In FIG. 18, the arrangement of data recorded on the writable disc RD will be described below.
On a new writable disc RD that has not been recorded yet, prepits are formed in advance at predetermined positions along the track. These prepits function as an address for accessing a predetermined position on the disc. Recording is performed by forming ON and OFF marks along the track with a laser beam. Marks are also made by changing the physical properties of the disk surface, such as reflectivity. The ON mark part is a part to which such a physical change is applied, and the OFF mark part is a part to which such a physical change is not applied. As shown in the lower part of FIG. 18, in the preferred embodiment of the present invention, the longest mark is the mark of the identification part ID and has a length of 14T. The identification part ID shown in FIG. 18 is formed by an ON mark, but conversely, it may be formed by an OFF mark (a mark corresponding to between two ON marks).

As shown in FIG. 18, the symbols written along the track on the writable disc RD are:
Sector address SA; synchronization code S1; data (eg video and audio data) and header code D / H; synchronization code S4; data and parity code D / P; synchronization code S3; data D; Sector address SA; synchronization code S2; data and header D / H; synchronization code S4: data and parity code D / P: ... synchronization code S4:
And parity code P.

  In the preferred embodiment of the present invention, the longest mark in the synchronization code is the identification part ID, and its length is 14T. The longest mark in the portion other than the synchronization code is 11T. Here, the mark may be either an ON mark or an OFF mark.

As shown in FIG. 19, the codes written along the tracks on the non-writable disc ND are:
Synchronous code S1: Data (eg video and audio data) and header code D / H; Synchronous code S4; Data and parity code D / P; Synchronous code S3; Data D; Synchronous code S4; Data and parity code D / P Synchronization code S3; data D;... Synchronization code S2; data and header code D / H;

  In the preferred embodiment of the present invention, the longest pit in the synchronization code is the identifier ID, and its length is 14T. The longest bit in the portion below the synchronization code is 11T. Here, the pit may be either an ON pit in which a pit is formed or an OFF pit between pits.

(Example 2)
FIG. 8 is a block diagram showing a configuration of an optical disc recording apparatus 800 according to the second embodiment of the present invention.

  The optical disc recording apparatus 800 includes an input unit 801, a memory 802, a parity generation unit 803, an encoding unit 804, a FIFO 805, a synchronous code insertion unit 806, a DSV calculation unit 807, a synchronous code pattern storage unit 808, and a DSV storage unit 809.

  The input unit 801 inputs data to be recorded on the optical disc, and writes the input data at a predetermined position in the memory 802 for each frame.

The memory 802 stores data other than the synchronization code in accordance with the predetermined format shown in FIG.
The parity generation unit 803 generates parity corresponding to the row element and column element of the input data written in the format shown in FIG. 1 at a predetermined position in the memory 802, and the generated parity is stored in the memory 802. Write in place.

  The encoding unit 804 sequentially reads data other than the synchronous code written in the memory 802 from the head of the block, and reads the data according to the 8-15 conversion table and conversion rules shown in FIGS. The data is converted into a code word, and the converted code word is written into the FIFO 805.

  The synchronization code insertion unit 806 counts the number of codewords written in the FIFO 805 and determines the type of synchronization code to be inserted at the head of the frame for each frame. If the type information of the synchronization code to be inserted at the head of the frame written in the FIFO 805 is selected by the DSV calculation unit 807, the synchronization code insertion unit 806 selects the code information of the selected type information and the fixed portion of the synchronization code. Is read from the synchronous code pattern storage unit 808, and the type information is inserted into a predetermined position of the fixed part of the synchronous code to generate a synchronous code. After outputting the generated synchronization code, the synchronization code insertion unit 806 reads out the frame following the synchronization code from the FIFO 805 and outputs it. The frame and the synchronization code output from the synchronization code insertion unit 806 are converted into an NRZI channel signal and written to a predetermined address on the optical disc or other recording medium.

  The DSV calculation unit 807 reads from the synchronization code pattern storage unit 808 the type information 1 and 2 for identifying the code pattern of the fixed portion of the synchronization code and the synchronization code determined by the synchronization code insertion unit 806, and type information 1 And the code sequence of the some synchronous code in which each type information 2 was inserted is generated. Next, it reads the code string input to the FIFO 805 from the frame following the synchronization code to the predetermined DSV comparison point of that frame, and the synchronization code including the type information 1 is inserted at the beginning of the code word string. In addition to generating a code word string, a code word string when a synchronization code including type information 2 is inserted at the head of the code word string is also generated.

  The DSV arithmetic unit 807 refers to the signal level of the NRZI channel signal held in the DSV storage unit 809, converts the two generated codeword strings into the NRZI channel signal, and stores the NRZI channel signal in the DSV storage unit 809. Based on the obtained DSV value, the DSV value of the NRZI channel signal of the two codeword strings is calculated. The DSV calculation unit 807 compares the absolute values of the two DSV calculation results at the end of the codeword string, that is, at the DSV comparison point following the synchronization code, and has the DSV calculation having the smallest absolute value at the DSV comparison point. The type information included in the result is selected. The DSV calculation unit 807 compares the contents stored in the DSV storage unit 809 with the DSV calculation result having the smaller absolute value at the DSV comparison point and the DSV calculation result of the NRZI channel signal having the smaller absolute value of the DSV calculation result. Update with the signal level at the point. Next, based on the content stored in the updated DSV storage unit 809, the DSV calculation unit 807 calculates again the DSV value from the DSV comparison point to the end of the frame, and calculates the content of the DSV storage unit 809 with the calculation result. Update again with the level of the last NRZI channel signal of the frame.

  The synchronization code pattern storage unit 808 is a 5-bit pattern of the type information 1 and the type information 2 corresponding to the type of the synchronization code S1 to S4 shown in FIG. And remember.

  The DSV storage unit 809 stores the DSV value updated by the DSV calculation unit 807 and the level of the NRZI channel signal corresponding thereto.

  FIG. 9 is a flowchart showing a processing procedure of a method for recording data with a synchronization code in the optical disc recording apparatus of the present embodiment.

  The data input to the input unit 801 (step S901) is sequentially written to a predetermined position in the memory 802 for each frame (step S902). When all the data is written in the memory 802 (step S903), parity is generated corresponding to each row element and each column element of the data in the memory 802 (step S904), and the generated parity is stored in the memory 802. It is written at a predetermined position (step S905).

  The synchronization code insertion unit 806 initializes each parameter for determining the type of the synchronization code to be inserted at the head of the data read from the memory 802. The DSV calculation unit 807 initializes the storage contents of the DSV storage unit 809.

  Specifically, the parameter for counting the first frame (i = 1) or the second frame i = 2) as the frame read from the memory 802 is i (frame value parameter i), and the number of rows in each frame is counted. , The parameter for counting is k (row value parameter k, 1 ≦ k ≦ 14), the parameter for counting the number of sectors is j (sector value parameter j, 1 ≦ j ≦ 12), i = 0, j = 1, Initialize to k = 1. As for the stored contents of the DSV storage unit 809, the initial level of the NRZI channel signal is set to, for example, a low level, and the initial value of the DSV is set to, for example, “0” (step S906).

  If there is unprocessed data in the memory 802 (step S907), the encoding unit 804 reads data from the memory 802 to a predetermined DSV comparison position (step S908), and converts the read data to 8-15 conversion. Thus, the read 8-bit data is encoded into a code word string made up of a 15-bit code word and written into the FIFO 805 (step S909).

  When the codeword string of a new frame is written into the FIFO 805, the synchronous code insertion unit 806 increments the parameter i (step S910).

  If the parameter i is i = 1 (step S911), the parameter k is k = 1 (step S912), and the parameter j is j = 1 (step S918), the synchronization code insertion unit 806 performs synchronization. The code insertion unit 806 determines that the type of the synchronization code to be inserted at the head of the frame written in the FIFO 805 is the synchronization code S1 indicating the head of the block (step S919).

  The DSV calculation unit 807 has the DSV value at the DSV comparison position in the first frame when the synchronization code having the type determined by the synchronization code insertion unit 806 is inserted at the head of the first frame written in the FIFO 805. Is calculated for both the case where the synchronization code has the type information 1 and the case where the synchronization code has the type information 2, and the type with the smaller absolute value of the DSV at the DSV comparison position in the first frame is calculated. Information is selected (step S920). Note that the processing procedure of step S920 will be described in more detail with reference to FIG.

  The synchronization code insertion unit 806 generates a synchronization code having the type information selected by the DSV calculation unit 807 (step S921).

  Next, the synchronization code insertion unit 806 extracts the first frame from the FIFO 805, and inserts the generated synchronization code at the head (step S916). Further, the codeword string for one frame written in the FIFO 805 is output (step S917), and the process returns to step S907.

  If the parameter i is i = 1 (step S911), the parameter k is k = 1 (step S912), and the parameter j is j ≠ 1 (step S918), the synchronous code insertion unit 806 sets the FIFO 805 to the FIFO 805. It is determined that the type of the synchronization code to be inserted at the head of the written frame is the synchronization code S2 indicating the head of the sector (step S922).

The DSV calculation unit 807 selects the type information of the synchronization code S2 in the same manner as the process of step S920 (step S923).
The synchronization code insertion unit 806 generates the synchronization code S2 having the type information selected by the DSV calculation unit 807 (step S924), and returns to the process of step S916.

  Furthermore, if the parameter k is k ≠ 1 (step S912), the synchronization code insertion unit 806 determines that the type of synchronization code to be inserted at the head of the frame written in the FIFO 805 is a row other than the block head and the sector head. It is determined that the synchronization code S3 indicates the head (step S913).

  The DSV calculation unit 807 selects the type information of the synchronization code S3 in the same manner as the process of step S920 (step S914).

  The synchronization code insertion unit 806 generates a synchronization code S3 having the type information selected by the DSV calculation unit 807 (step S915), and returns to the process of step S916.

  If the parameter i is i = 2, that is, if i = 1 is not satisfied (step S911), the synchronization code insertion unit 806 determines that the type of the synchronization code to be inserted at the head of the frame written in the FIFO 805 is each row. Is determined to be the synchronization code S4 indicating the head of the second frame located in the middle (step S925).

  The DSV calculation unit 807 selects the type information of the synchronization code S4 in the same manner as the process of step S914 (step S926).

  The synchronization code insertion unit 806 generates a synchronization code S4 having the type information selected by the DSV calculation unit 807 (step S927).

  Furthermore, since the next frame to be written in the FIFO 805 is the first frame of the next row, the synchronization code insertion unit 806 sets the parameter i to i = 0, increments the parameter k, and sets the parameter k to k = 1 (step S929).

  At this time, if the parameter k is 14 <k (step S930), the next frame to be written to the FIFO 805 is the first frame of the next sector, so the parameter j is incremented and the parameter k is set to k = 1. (Step S931). If the parameter k is not 14 <k (step S930), the process jumps after step S916.

  If the result of incrementing the parameter j in step S932 is 12 <j, the next frame to be written to the FIFO 805 is the first frame of the next block, so the parameter j is set to j = 1 (step 1 S933), the process returns to step S901.

  Returning from step S916 to step S907, the encoding unit 804 ends the process when there is no unprocessed data in the memory 802.

  FIG. 10 is a flowchart showing the procedure of the type information selection process in step S914, step S920, step S923, and step S926 shown in FIG.

  The DSV calculation unit 807 reads the 5-bit pattern of type information 1 and 2 indicating the type determined by the synchronous code insertion unit 806 and the code pattern of the fixed part of the synchronous code from the synchronous code pattern storage unit 808 (step S1001). ).

  Next, the 5-bit pattern of the read type information 1 is inserted into the positions from the 22nd bit to the 26th bit of the code pattern of the fixed portion of the synchronous code read out simultaneously, and the code representing the determined type of synchronous code Column A is generated (step S1002).

  Similarly, the DSV calculation unit 807 inserts the 5-bit pattern of the read type information 2 into the positions from the 22nd bit to the 26th bit of the code pattern of the fixed portion of the synchronous code that is read at the same time. A code string B representing the type of synchronization code is generated (step S1003).

  The DSV calculation unit 807 reads the code word string C from the beginning of the frame stored in the FIFO 805 to a predetermined DSV comparison point (step S1O04). The DSV calculation unit 807 further inserts the synchronous code sequences A and B generated in steps S1002 and S1003 at the head of the codeword sequence C of the frame read by the FIFO 805, thereby generating two code sequences A + C and B + C. (Step S1005).

  The DSV calculation unit 807 generates the NRZI channel signal corresponding to the generated code strings A + C and B + C based on the level of the NRZI channel signal in the immediately preceding bit of the synchronization code and the value held in the DSV storage unit 809 (Step S1006).

  The DSV calculation unit 807 calculates the DSV value of the NRZI channel signal corresponding to the code strings A + C and B + C based on the DSV value immediately before the synchronization code stored in the DSV storage unit 809 (step S1007).

  The DSV calculation unit 807 is generated for the absolute value | d1 | of the DSV calculation result at the end of the NRZI channel signal generated for the code sequence A + C having the type information 1 and the code sequence B + C having the type information 2. The absolute value | d2 | of the DSV calculation result at the end of the NRZI channel signal is compared.

  If | d1 | ≦ | d2 | (step S1008), the type information 1 is selected (step S1009). The DSV calculation unit 807 further writes the level of the NRZI channel signal at the end of the NRZI channel signal generated for the code string A + C having the type information 1 and the DSV calculation result d1 in the DSV storage unit 809, and stores the DSV storage The stored contents of the unit 809 are updated, and the type information selection process is terminated (step S1010).

The absolute values | d1 | and | d2 | of the calculation results d1 and d2 are compared. If | d1 |> | d2 |, that is, if the result in step S1008 is NO, the DSV calculation unit 807 Information 2 is selected (step S1011).

  The DSV calculation unit 807 further writes the level of the NRZI channel signal at the end of the NRZI channel signal generated for the code string B + C having the type information 2 and the DSV calculation result d2 in the DSV storage unit 809, and stores the DSV storage The content stored in the unit 809 is updated, and the type information selection process is terminated (step S1012).

  As described above, according to the present embodiment, as described in the first embodiment, the synchronization code into which the synchronization code having various functions and can be accurately identified from data other than the synchronization code is inserted. A recording apparatus 800 and a recording method for recording attached data on an optical disk or other recording medium can be provided.

  Further, the recording medium can be considered as a transmission path for transmitting the data with the synchronization code recorded in the recording device to the reproducing device. Therefore, according to the present embodiment, as described in the first embodiment, data with a synchronization code having a variety of functions and having a synchronization code inserted that can be accurately identified from data other than the synchronization code is provided. A transmission method for transmitting to a transmission line can be provided.

(Example 3)
FIG. 11 is a block diagram showing the configuration of the optical disc playback apparatus 1100 of the present embodiment. The optical disc playback apparatus 1100 includes a synchronization code identification unit 1101, a type information reading unit 1102, a reading control unit 1103, a decoding unit 1104, an error correction unit 1105, and an output unit 1106.

  A synchronization code identification unit 1101 extracts data with a synchronization code recorded on an optical disk as a reproduction signal, digitizes the extracted reproduction signal to convert it into an NRZI channel signal, and further converts the NRZI channel signal into a 15-bit codeword. Is decoded into a code word string (parallel data) and output to the type information reading unit 1102. In addition, the synchronization code identification unit 1101 identifies a signal portion having an inversion interval of 16T or more in the decoded NRZI channel signal as a synchronization code identification unit, and sends the synchronization code detection signal to the type information reading unit 1102. Output.

  When the signal portion of the NRZI channel whose inversion interval is 16T or more is identified, the synchronization code identifying unit 1101 reads the set signal and outputs it to the control unit 1103.

  The type information reading unit 1102 is actually the same as the decoding unit 1104, but the code word passed from the synchronous code identifying unit 1101 immediately after the identifying unit is identified by the synchronous code identifying unit 1101, that is, A code word including the synchronization code type information immediately after the synchronization code detection signal is read as data. The read type information is sent to the read control unit 1103.

  The reading control unit 1103 reads each time the NRZI channel signal is inverted, and synchronizes the clock cycle and phase, and the synchronization code identification unit 1101 has a synchronization code identification unit (that is, a part of the NRZI channel signal has an inversion interval TS 16T), that is, at the timing of the set signal, the first bit of the code word passed from the synchronization code identification unit 1101 to the type information reading unit 1102 is synchronized. Further, the reading control unit 1103 reads the content of the data decoded by the decoding unit 1104 and controls the operation of each component of the optical disc playback apparatus 1100.

  The decoding unit 1104 performs inverse conversion of 8-15 conversion for each predetermined amount of the 15-bit code word passed from the synchronous code identification unit 1101, and writes it in a predetermined position in a memory (not shown).

The error correction unit 1105 reads the parity from data written at a predetermined position in a memory (not shown) and performs error correction processing. The data stored in the memory is updated using the data subjected to error correction.
The output unit 1106 sequentially reads out the error-corrected data from a memory (not shown) and outputs the data.

FIG. 12 is a block diagram illustrating a hardware configuration of the synchronization code identification unit 1101 and the reading control unit 1103 illustrated in FIG.
The synchronization code identification unit 1101 and the read control unit 1103 include a comparator 1201, a threshold value generation unit 1202, a clock extraction unit 1203, a bit synchronization unit 1204, a shift register 1205, an identification unit 1206, a 1/15 frequency divider 1207, and a latch circuit. 1208.

  The comparator 1201 compares the reproduction signal reproduced from the optical disc with the reading threshold value input from the threshold value generation unit 1202, and reads a value equal to or higher than the reading threshold value in the reproduction signal to a high level. A value less than the threshold value is converted to a low level, and the input reproduction signal is digitized.

The threshold generation unit 1202 generates a reading threshold for the comparator 1201.
The clock extraction unit 1203 includes a PLL (Phase Lock Loop), and synchronizes the cycle and phase of the read clock so that the output of the comparator 1201 is inverted at an intermediate position of the generated read clock.

The bit synchronization unit 1204 samples the output of the comparator 1201 at the timing of the read clock from the clock extraction unit 1203, converts the reproduction signal into an NRZI channel signal, and converts the converted NRZI channel signal into NRZ (non return to zero). Demodulate to signal.
The shift register 1205 sequentially inputs an NRZ signal representing a code word as serial data at the clock timing from the clock extraction unit 1203 and outputs the NRZ signal as 15-bit parallel data to the latch circuit 1208.

  When the NRZ signal indicating “10000000000000000001” corresponding to the inversion interval 16T of the NRZI channel signal or “100000000000000001” corresponding to the inversion interval 17T of the NRZI channel signal is input, the identification unit 1206 identified the identification unit of the synchronization code A synchronization code detection signal indicating this is output to the type information reading unit 1102. When an NRZ signal indicating “10000000000000001” corresponding to the inversion interval 16T of the NRZI channel signal is input, a set signal is output to the 1/15 frequency divider 1207, and at a timing two read clocks before the set signal, The phase of the 1/15 divider 1207 is synchronized so that a read clock (word clock) divided by 1/15 is output.

  The 1/15 frequency divider 1207 generates a word clock obtained by dividing the read clock by 1/15. The 1/15 frequency divider 1207 synchronizes the phase of the word clock, and the rising edge (or falling edge) of the word clock is before the third read clock from the set signal output, that is, at the twelfth read clock from the set signal. Is output.

  The latch circuit 1208 holds the 15-bit parallel data from the shift register 1205 at the timing of the word clock from the 1/15 frequency divider 1207 and outputs it to the decoding unit 1104.

  FIG. 13 is a block diagram illustrating a hardware configuration of the shift register 1205 and the identification unit 1206 illustrated in FIG. In FIG. 13, the upper bits of the code string from the shift register 1205 are shown on the right side, and the lower bits are shown on the left side. The nth bit counted from the most significant bit (MSB) of the output of the shift register 1205 is hereinafter simply referred to as bit n.

The identification unit 1206 includes an OR circuit 1301, an inverter 1302, a NOR circuit 1303, an AND circuit 1304, and an AND circuit 1305.
Bits 17 and 18 of the parallel data output from the shift register 1205 are input to the OR circuit 1301. If at least one of the inputs is “1”, “1” is output.

Bit 1 of the parallel data output from the shift register 1205 is input to the inverter 1302, the input bit is inverted, and the inverted bit is output.
Bits 1 to 16 (where bit 1 is inverted by the inverter 1302) of the barrel data output from the shift register 1205 are input to the NOR circuit 1303. If all inputs are “0”, the NOR circuit 1303 outputs “1”.

The output from the NOR circuit 1303 and the bit 17 from the shift register 1205 are input to the AND circuit 1304. If both inputs are “1”, “1” is output.
The output of the NOR circuit 1303 and the output of the OR circuit 1301 are input to the other AND circuit 1305. If both inputs are “1”, “1” is output.

The overall operation of the identification unit 1206 will be described in detail below.
As shown in FIG. 13, among the outputs from the shift register 1205, the first bit is input to the NOR circuit 1303 via the inverter 1302, and the second bit to the 16th bit are directly input. As a result, the NOR circuit 1303 outputs 1 only when the first bit of the shift register 1205 is “1” and all the bits from the second bit to the 16th bit are “0”. The AND circuit 1304 receives the output of the NOR circuit 1303 and the 17th bit output of the shift register 1205. The AND circuit 1304 outputs the first bit and the 17th bit of the output of the shift register 1205. "1" is output only when all the bits from the second bit to the 16th bit are "0". This bit string corresponds to a code string indicating the identification part of the synchronization code represented by the inversion interval TS = 16T of the NRZI signal. The output of the AND circuit 1304 is used as a set signal for matching the phase of the 1/15 frequency divider 1207. Accordingly, when the inversion interval TS of the NRZI channel signal is shifted by ± T due to factors such as noise, and TS = 17T, the set signal is not generated.

  Of the outputs from the shift register 1205, the 17th and 18th bits are input to the OR circuit 1301. The AND circuit 1305 receives the output of the NOR circuit 1303 and the output of the OR circuit 1301. Therefore, the AND circuit 1305 has a first bit “1” in the output of the shift register 1205, and the first bit. If all the bits from the 2nd bit to the 16th bit are “0” and one of the 17th and 18th bits is “1”, “1” is output. The output of the AND circuit 1305 is output to the type information reading unit 1102 as a synchronization code detection signal. Therefore, the synchronization code detection signal is output even when a deviation of ± T occurs in the inversion interval TS of the NRZI signal due to factors such as noise and TS = 17T.

  Further, the output “1” from the AND circuit 1305 indicates that even if a slight read error occurs when reading data including the sync code, the sync code is correctly identified from other data, and the read error that occurs is It is assumed that the error is within the allowable correction range of the error correction process. Accordingly, the output from the AND circuit 1305 is sent to the type information reading unit 1102 as a synchronous code detection signal.

  As a result, a deviation of ± T occurs in the inversion interval TS of the NRZI channel signal due to factors such as noise, and even when TS = 17T, the identification part of the synchronization code can be detected and the type information of the synchronization code can be read. it can. Also, when the inversion interval TS of the NRZI channel signal is TS = 17T, it cannot be determined whether the inversion position shift occurs on the rising or falling side of the NRZI signal corresponding to the identification part of the synchronization code. Therefore, the synchronization code in which the inversion interval TS of the NRZI channel signal of the identification unit is TS = 17T is not suitable for use in detecting the first bit of the code word. Therefore, the code word of the data consisting of the code word string can be accurately read by detecting the first bit of the code word using only the identification part of the synchronous code that does not cause a reading error.

  As shown in FIG. 1, in this embodiment, the sector address SA is provided immediately after each of the synchronization codes S1 and S2. The sector address SA12 includes a 4-byte address part, a 2-byte error correction part, and a 6-byte attribute part. Each sector address holds a block address and a sector address. Further, a 4-byte error detection code EDC is provided at the end of each sector and before the parity part, and checks for errors in the data area.

The operation of the optical disc playback apparatus 1100 according to the present invention will be described in detail with reference to the flowchart of FIG.
From the head of the optical disk playback apparatus 1100, a playback signal representing data with a synchronization code recorded on the optical disk is input to the synchronization code identification unit 1101 (step S1401).

  The synchronization code identification unit 1101 extracts the NRZI channel signal from the reproduction signal, further demodulates it to the NRZ signal (step S1402), and identifies the identification unit of the synchronization code included in the NRZ signal, that is, the corresponding NRZI channel signal. A signal portion with inversion interval TS ≧ 16T is identified, and a synchronization code detection signal is output to the type information reading unit 1102 (step S1403).

  The type information reading unit 1102 decodes and reads the code word read immediately after the synchronous code detection signal is output as the code word part of the synchronous code, and identifies the type of the synchronous code (step S1404).

  The read control unit 1103 determines that the synchronization code whose type is identified is the synchronization code S1 (step S1405), the insertion position of the synchronization code S1 is the beginning of the desired block (step S1406), and the end of the block from the middle Is already read in the memory (step S1407), the read control unit 1103 reads the first half of the block from the head of the block to the sector address detected and retained in step 1417 (step S1408). ), And inserted in the front part of the data read out in the memory (step S1409). In this way, the first half and the second half of the data are combined to generate data for one completed block.

The read control unit 1103 reads the data for one block up to immediately before the next synchronization code S1 unless the data of the block is read from the middle, that is, the latter half is read into the memory (step S1407). Step S1410) and writing into the storage unit (step S1411).
The error correction unit 1105 performs error correction on one block of data written in the memory (step S1412).

The data in which the error is corrected is sequentially read from the memory and output (step S1413).
If the synchronization code whose type is identified is not the synchronization code S1 (step S1405) and the synchronization code whose type is identified is the synchronization code S2 (step S1414), the reading control unit 1103 follows the synchronization code S2. A sector address written in one frame is read to check whether the sector is in a desired block (step S1415).

  If the sector is a sector in a desired block from the read address SA (step S1416), the sector address SA is stored separately (step S1417), and data up to immediately before the next synchronization code S1, that is, the latter half The block data is read (step S1418), written to a predetermined position in the memory (step S1419), and the process returns to step S1401.

  As described above, according to the present embodiment, as described in the first embodiment, the synchronization code into which the synchronization code having various functions and can be accurately identified from data other than the synchronization code is inserted. A method for reading attached data from a recording medium can be provided. Therefore, according to this method, data recorded on a recording medium such as an optical disk can be retrieved at high speed and read accurately, and when a reading error occurs, correct data is corrected with high correction capability. Can be output.

  Further, the recording medium can be considered as a transmission path for transmitting the data with the synchronization code recorded in the recording device to the reproducing device. Therefore, according to the present embodiment, as described in the first embodiment, data with a synchronization code having a variety of functions and having a synchronization code inserted that can be accurately identified from data other than the synchronization code is provided. A reading method of reading from the transmission path can be provided.

  The DSV is counted separately for each block. However, when recording a plurality of blocks continuously, the DSV is cleared to “0” before the first block, and thereafter, between the plurality of blocks. The DSV may be counted continuously.

Example 4
In the following, data with a synchronization code devised so that it is possible to specify the position of each frame within a sector by determining the type of the synchronization code using FIGS. 15 to 17 is recorded. The recording medium is described.

  FIG. 15A and FIG. 15B are configuration diagrams showing synchronization-signed data further devised as data before modulation written to the recording medium of the present embodiment. FIG. 15A shows synchronously signed data in the head physical sector of the block. FIG. 15B shows data with a synchronization code in a physical sector other than the head of the block. 15A and 15B are conceptual diagrams showing a configuration in which the data for one sector is virtually arranged in two dimensions.

  On the optical disc, data with a synchronous code, in which one block of 12 sectors is one unit of error correction processing, is encoded and modulated and written. In each sector, data of 1365 channel bits obtained by converting 91 bytes of data into a code word is used as one frame, and 2 frames × 13 rows of data are written. Further, 31-channel bit synchronization codes SYS0 to SYS5 are inserted at the head of each frame.

  The synchronization code SYS0 indicates that the sector including the synchronization code SYS0 is the first sector of the block, and that the row including the synchronization code SYS0 is the first row of the sector.

  The synchronization code SYS1 indicates that the sector including the synchronization code SYS1 is a sector other than the first sector of the block, and that the line including the synchronization code SYS1 is the first line of the sector.

  The synchronization code SYS0 to SYS5 indicates whether the frame following the synchronization code SYS0 to SYS5 having the second type is the first frame or the second frame by combining two consecutive types S0 to S5. .

  Specifically, if the number part of “S1 to S5” representing the type of the synchronization code is called a type number, the type number of the synchronization code SYS1 is “1”, and the type number of the synchronization code SYS2 is “2”. Is. However, the type number of SYS0 is handled as “1”. As shown in FIG. 15, in each section, when two consecutive type numbers are added, if the value is an odd number, the frame following the synchronization code having the second type is the first frame. If the number is even, the arrangement of the synchronization codes SYS0 to SYS5 is determined so that the frame following the synchronization code having the second type is the second frame.

  Furthermore, the synchronization codes SYS0 to SYS5 can specify the position in the sector of the frame following the synchronization code SYS0 to SYS5 having the third type by combining three consecutive types S0 to S5. .

  Specifically, as shown in FIG. 15, the arrangement of the synchronization codes SYS0 to SYS5 is determined so that the same combination of three consecutive types S0 to S5 does not appear in the same sector. ing. Accordingly, by storing the position of the frame following the synchronization code SYS0 to SYS5 having the third type corresponding to the combination of three consecutive types S0 to S5, each frame in each sector is stored. Can be specified.

  FIG. 16 is an explanatory diagram showing the data structure of the synchronization codes SYS0 to SYS5 of this embodiment. In FIG. 16, “X” indicates a bit whose code value may be either 0 or 1.

  The synchronization codes SYS0 to SYS5 are represented by a 31-bit code string. From the third bit to the 19th bit, the synchronization code S1 to S4 shown in FIG. 4 has the same inversion interval as the corresponding NRZI signal TS = Tmax + 2T. = 16T has an identification part. The first 21 bits and the last 4 bits of the synchronization codes SYS0 to SYS5 are fixed parts common to the synchronization codes SYS0 to SYS5, and are represented by two types of patterns in 6 bits from the 22nd bit to the 27th bit. Type information is inserted. In FIG. 15, the first 16 bits of the synchronization codes SYS0 to SYS5 are represented as a flag part SY, and the latter 15 bits are represented as a code word part S0 to S5.

FIG. 17 is a table showing the type information of the synchronous code and the read value of the code word portion corresponding to the synchronous code type according to this embodiment.
As already described, since the synchronization codes SYS0 to SYS5 alone cannot specify the position in the block of the frame following the synchronization code, the type information 1 and type information 2 of each of the synchronization codes SYS0 to SYS5 are It simply represents the type of the synchronization code.

  Similar to the table shown in FIG. 6, the type information of each of the synchronization codes SYS0 to SYS5 includes type information 1 including an odd number of “1” and a type including an even number of “1” in a 6-bit pattern. It is expressed as information 2. As in the first embodiment, the type information 1 and the type information 2 are selected so that the absolute value of the DSV at a predetermined DSV comparison position in the frame following the synchronization code SYS0 to SYS5 becomes smaller. It is inserted from the 22nd bit to the 27th bit of the code string of codes SYS0 to SYS5. The code word parts S0 to S5 including the type information are read in the same manner as other code words immediately after the identification parts of the synchronization codes SYS0 to SYS5 are detected. If the value of the read codeword part is, for example, “119” or “138”, it is understood that the synchronization code is the synchronization code SYS0. The types of the other synchronization codes SYS1 to SYS5 can be read in the same manner.

  As described above, according to the present embodiment, in addition to the effects of the first embodiment, the position of each frame in each sector can be specified. For example, when the target block is accessed, Even if you start reading from the middle of the sector in the target block, the frame from the frame to the last sector of the target block is temporarily extracted to the memory, and then from the beginning of the target block to the remaining frames By replenishing before the data fetched in the memory, the data of the target block can be read out in a short time.

  Note that the arrangement of the synchronization codes SYS0 to SYS5 shown in FIG. 15 is not limited to the arrangement shown in the figure. When two consecutive type numbers are added, the value of the addition result has the second type number. It has an attribute that can specify whether the frame following the code is the first frame or the second frame, and it is determined that multiple identical patterns with three consecutive type numbers do not appear in the same sector It only has to be. Further, instead of the addition result, another calculation result may be used. Further, the three consecutive type number patterns may be two consecutive type number patterns as long as the same pattern is determined not to appear in the same section. Moreover, the pattern of the type number which continues 4 or more may be sufficient.

  Also, the 6-bit pattern of type information 1 and type information 2 is not limited to the pattern shown in FIG. 17 as in the case of the first embodiment, and the correspondence with the types of synchronization codes S0 to S5 is It is not limited to the correspondence shown in FIG.

  As described above, according to the present invention, by detecting an identification code representing a synchronization code, it is possible to identify the synchronization code in the information recorded on the recording medium and obtain frame synchronization. By reading the type code arranged immediately after the code, a codeword sequence with a synchronous code that can be obtained is information that is expressed by the type of the synchronous code and that represents information other than the synchronous code The recording medium can be provided.

  According to the first aspect of the present invention, it is possible to provide a recording medium on which a codeword sequence with a synchronization code that can know the position in the block of the synchronization code by reading the type code is recorded.

  According to the second aspect of the present invention, the synchronization code can be identified from a codeword sequence other than the synchronization code by the specific pattern of the identification code, and includes information represented by the type code and the type code. If the information represented by the code word to be formed is stored in association with each other, a special configuration for reading the type code is not required, and the code word formed including the type code is the code word group. A recording medium on which a codeword sequence with a synchronization code into which such a synchronization code is inserted is recorded can be read as one of the above and the position in the block of the synchronization code represented by the type code can be known be able to.

According to the third aspect of the present invention, by reading the type code, it is possible to know the position in the block of the synchronous code, and there is a bias in the DC component of the reproduction signal reproduced from the recording medium of the present invention. It is possible to provide a recording medium on which a codeword sequence with a synchronization code in which a synchronization code selected to be smaller is inserted is recorded.

  According to the fourth aspect of the present invention, since the frame including the address information of the sector can be easily known by the type code of the synchronous code, by reading only the type information and the address information in the synchronous code, Recording medium on which a codeword sequence with a synchronization code is recorded so that a search for reading a desired block can be performed at a high speed and a codeword sequence with a synchronization code can be read from the middle of the desired block Can be provided.

  According to the fifth aspect of the present invention, the identification code indicates that the synchronization code is different from the codeword sequence other than the synchronization code, and the type code indicating the type of the synchronization code indicates information corresponding to the synchronization code insertion position. Thus, it is possible to provide a recording method for recording on a recording medium a codeword sequence with a synchronization code in which a synchronization code that can represent information other than the synchronization code is inserted.

  According to the sixth aspect of the present invention, the synchronization code can be identified from a codeword sequence other than the synchronization code by the specific pattern of the identification code, and includes the information represented by the type code and the type code. If the information represented by the code word to be formed is stored in association with each other, a special configuration for reading the type code is not required, and the code word formed including the type code is the code word group. A recording method for recording on a recording medium a codeword sequence with a synchronization code into which the synchronization code is inserted, the position in the block of the synchronization code represented by the type code can be known Can be provided.

  According to the seventh aspect of the present invention, by reading the type code, the position in the block of the synchronous code can be known, and the bias of the DC component of the reproduction signal reproduced from the recording medium of the present invention can be obtained. It is possible to provide a recording method for recording on a recording medium a codeword sequence with a synchronization code in which a synchronization code selected to be smaller is inserted.

  According to the eighth aspect of the present invention, since the frame including the address information of the sector can be easily known by the type code of the synchronization code, by reading only the type information and the address information in the synchronization code, A codeword sequence with a synchronization code that can perform a search for reading a desired block at a high speed and can read a codeword sequence with a synchronization code from the middle of the desired block is recorded on a recording medium. A recording method can be provided.

  According to the ninth aspect of the present invention, the synchronization code can be accurately identified from the codeword sequence with the synchronization code recorded on the recording medium of the first aspect, and the read clock can be synchronized with the codeword. In addition, it is possible to provide a reproduction method that can selectively read the information recorded immediately after the synchronization code by specifying the position of the information recorded immediately after the synchronization code in the block. .

  According to the tenth aspect of the present invention, the code pattern formed by including the type code and the synchronization code can be accurately identified and the read clock can be synchronized with the code word by the specific pattern of the identification code. Is read as one of the codeword groups, and the information recorded immediately after the synchronization code is selectively read by specifying the position of the information recorded immediately after the synchronization code in the block. A reproducible reproduction method can be provided.

  According to the eleventh aspect of the present invention, since the frame including the address information can be easily known from the recording medium according to the fourth aspect by the type code of the synchronous code, the type information and the address information in the synchronous code can be obtained. By reading only, it is possible to perform a search for reading a desired block at a high speed, and to provide a reproduction method capable of reading a codeword sequence with a synchronous code from the middle of the desired block .

  Various modifications are possible based on the present invention described above. Such modifications are included in the scope of the present invention, and modifications conceived by those skilled in the art should be included in the following claims.

It is a block diagram which shows the data with a synchronous code as the data before the modulation | alteration written in the recording medium of 1st Example of this invention. It is a conversion table which shows the conversion example of 8-15 conversion in a present Example. It is a conversion table which shows the conversion example of 8-15 conversion in a present Example. It is explanatory drawing which shows the data structure of the synchronous codes S1-S4 of a present Example. It is explanatory drawing which shows the relationship between the reproduction signal reproduced | regenerated from the optical disk of a present Example, and the NRZI channel signal read from the said reproduction signal. It is a table | surface which shows the read value of the code | symbol part corresponding to the classification information of the synchronous code of a present Example. It is explanatory drawing explaining the selection method of the classification information 1 or the classification information 2 in the synchronous code of a present Example. It is a block diagram which shows the structure of the optical disk recording device which is 2nd Example of this invention. It is a flowchart which shows the process sequence of the recording method of the data with a synchronous code in the optical disk recording device of a present Example. 10 is a flowchart showing a procedure of type information selection processing in step S914, step S920, step S923, and step S926 shown in FIG. It is a block diagram which shows the structure of the optical disk reproducing | regenerating apparatus of 3rd Example of this invention. It is a block diagram which shows the hardware constitutions of the synchronous code identification part 1101 and the reading control part 1103 which were shown in FIG. It is a block diagram which shows the hardware constitutions of the shift register evening and identification part shown in FIG. It is a flowchart which shows the process sequence of reproduction | regeneration of the optical disk reproducing | regenerating apparatus 1100 of a present Example. It is a block diagram which shows the data with a synchronous code further devised as the data before the modulation | alteration written in the recording medium of another Example of this invention. It is a block diagram which shows the data with a synchronous code further devised as the data before the modulation | alteration written in the recording medium of another Example of this invention. It is explanatory drawing which shows the data structure of the synchronous codes SYS0-SYS5 of another Example. FIG. 10 is a diagram similar to FIG. 6, and is a table showing the type information of the synchronization code of another embodiment and the read value of the code word part corresponding thereto. FIG. 2 is a plan view of a writable optical disc according to the present invention, showing the arrangement of marks. FIG. 2 is a plan view of a non-writable optical disc according to the present invention, showing the arrangement of marks. It is explanatory drawing which shows the data format of 1 block used as the processing unit of the conventional error correction.

Explanation of symbols

800 Optical disk recording device 801 Input unit 802 Memory 803 Parity generation unit 804 Encoding unit 805 FIFO
806 Sync code insertion unit 807 DSV calculation unit 808 Sync code pattern storage unit 809 DSV storage unit 1100 Optical disk playback device 1101 Sync code identification unit 1102 Type information reading unit 1103 Reading control unit 1104 Decoding unit 1105 Error correction unit 1106 Output unit 1201 Comparator 1202 Threshold generation unit 1203 Clock extraction unit 1204 Bit synchronization unit 1205 Shift register 1206 Identification unit 1207 1/15 frequency divider 1208 Latch circuit

Claims (6)

A plurality of codewords form a frame, and a plurality of frames form a data block which is a unit for performing error correction processing , and the data block includes a plurality of sectors which are minimum units having accessible addresses. A method of recording a codeword string on a recording medium,
(A) adjacent to the top of the frame by inserting the synchronization code,
(B) providing each synchronization code with a single type of identification code for distinguishing the synchronization code of the frame from other codes;
(C) based on the position within the sector synchronous code is inserted, to indicate the type of synchronization code, first that the type information of a predetermined constant length Yusuke even number of "1" added to each synchronization code selected from the type information and second type information that Yusuke odd number of "1",
(D) generating a channel signal from the data block in which the synchronization code is inserted;
(E) viewing including the step of recording the channel signal,
A recording method characterized in that a position in a sector is specified by using a plurality of types information . A plurality of codewords form a frame, and a plurality of frames form a data block which is a unit for performing error correction processing , and the data block includes a plurality of sectors which are minimum units having accessible addresses. A recording apparatus for recording a channel signal generated by a codeword string on a recording medium,
And inserting means for inserting a synchronization code adjacent to the head of the frame,
First providing means for providing each synchronization code with a single type of identification code for distinguishing the synchronization code of the frame from other codes;
Based on the position within the sector synchronous code is inserted, to indicate the type of synchronization code, the first type information that the type information of a predetermined constant length Yusuke even number of "1" second applying means for applying to each synchronization code selected from a second type information that have a "1" in an odd number and,
For recording on a recording medium, viewed including output means for outputting a channel signal code synchronization are generated in the form of inserted data blocks,
A recording apparatus characterized in that a position in a sector is specified by using a plurality of types information .   It is added to the DSV value cumulatively added from the predetermined position to immediately before the synchronization code, and until the predetermined position of the frame following the synchronization code when the synchronization code including the type information 1 or the type information 2 is inserted. The DSV value is calculated for both the type information 1 and the type information 2, and the type information with the smaller absolute value of the DSV up to a predetermined position of the frame following the synchronization code is selected. The recording method according to 1.   This is added to the DSV value cumulatively added from the beginning of the data to be recorded to immediately before the synchronization code, and follows the synchronization code when the synchronization code having the type information 1 corresponding to the type of the synchronization code is inserted. A DSV value at a predetermined position of the frame and a DSV value at a predetermined position of the frame following the synchronization code when the synchronization code having the type information 2 corresponding to the type of the synchronization code is inserted are calculated. 2. The recording method according to claim 1, wherein the type information having a smaller absolute value of DSV at a predetermined position of the frame following is selected.   It is added to the DSV value cumulatively added from the predetermined position to immediately before the synchronization code, and until the predetermined position of the frame following the synchronization code when the synchronization code including the type information 1 or the type information 2 is inserted. The DSV value is calculated for both the type information 1 and the type information 2, and the type information with the smaller absolute value of the DSV up to a predetermined position of the frame following the synchronization code is selected. 2. The recording device according to 2.   This is added to the DSV value cumulatively added from the beginning of the data to be recorded to immediately before the synchronization code, and follows the synchronization code when the synchronization code having the type information 1 corresponding to the type of the synchronization code is inserted. A DSV value at a predetermined position of the frame and a DSV value at a predetermined position of the frame following the synchronization code when the synchronization code having the type information 2 corresponding to the type of the synchronization code is inserted are calculated. 3. The recording apparatus according to claim 2, wherein the type information having a smaller absolute value of DSV at a predetermined position of the frame following is selected.

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