JPH08329616A - Device and method for recording/reproducing data and data recording medium - Google Patents

Abstract

PURPOSE: To identify a sector size by a bit pattern of sync added after digitally modulated when the data of plural sector sizes are recorded/reproduced. CONSTITUTION: The data for a high density optical disk from a host computer 1 or the CD-ROM data from a CD-ROM driver 2 are converted into the data of the different sector size by format forming circuits 5a, 5b. Then, they are converted to the data of the same block size by a block forming circuit 7. The block formed data are supplied to an optical pickup 10 through a recording processing circuit 8 and a driver 9 to be recorded on the high density optical disk 3. In a sync addition circuit connected to the modulation circuit of the recording processing circuit 8, an ID signal specifying the sector size and the sector sync of the answering bit pattern are added to the data. At a reproducing time, the bit pattern of the sector sync is detected in a reproducing processing circuit 23, and the ID signal according to the detection result is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording medium having different formats, and more particularly to a data recording / reproducing apparatus and method capable of simplifying signal processing between data recording media having different sector sizes, and a data recording medium. .

[0002]

2. Description of the Related Art As an external storage device of a computer, an optical disk drive has been attracting attention because of its advantages of large capacity and high speed access, and it has already been a CD-ROM (or CD-I
(nteractive)) drive and MO (magneto-optical disc), which is one of the erasable discs, are being adopted rapidly. In addition to these, an MD (mini disk; erasable disk) having a disk diameter of 2.5 inches is also proposed. Furthermore, a DVD (digital video disc) is being developed as a video storage medium.

A DVD is a recordable / reproducible optical disc that is a read-only disc having the same diameter as a CD, or an MO disc or a phase change type disc.
It is a disc that can reproduce or record / reproduce video information compressed by G or the like. In DVD, the recording density is further improved by the progress of the shortening of the wavelength of laser light, the increase of NA of the objective lens, and the improvement of the processing of digital modulation and error correction coding. Even in the case of a single layer disc,
The data storage capacity is enormous, about 3.7 GB. CDs and MDs were originally developed as digital audio discs, and then used as external storage media for computers.
Is also expected to be used as an external storage medium of a computer.

Conventionally, different formats have been defined for each medium such as a magnetic tape, a magnetic disk, a flexible disk and the above-mentioned optical disk, and it cannot be said that compatibility is taken into consideration. Therefore, when the compatibility between the new medium and the existing medium is taken, it is not efficient because it can be dealt with only in the logical area. For example, in the case of an external storage medium of a computer, a sector size of 128 bytes × 2 ⁱ (512 bytes, 2 Kbytes, etc.) is the mainstream, while a CD-ROM has 2352 bytes (when the synchronization signal is excluded, , 2340 bytes, and 2336 bytes when the sync signal and the header are excluded) make up one block, and there is a problem in that it is physically difficult for both to correspond.

The above-mentioned DVD can be realized by a recordable MO disc or a phase change type disc, and its capacity is larger than that of any existing optical disc.
It has the advantage of being quite large. When such a DVD is newly used as an external storage medium, an existing optical disc medium, in particular, a CD-ROM which has been widely spread and has substantially the same disc size and adopts the same reading method, Considering the compatibility of CD-R
Mutual loading of data between OM and DVD is made easy, and the drive can be shared.
-It is indispensable for utilizing ROM assets.

The inventor of the present application has previously found that the Japanese Patent Application Laid-Open No. 7-73593.
In the publication, in order to simplify the mutual loading of data between the CD-ROM and the MO, a method is proposed in which the storage capacity per recording block unit of the MO disk is 2352 bytes. This method adjusts the storage capacity per recording block of the MO disk to that of the CD-ROM. Even if it can be applied when a new data structure of the disk is established, the data of the disk cannot be recorded. If the structure is standardized to some extent, there are problems that cannot be applied. Therefore, it is preferable that data of a plurality of sector sizes can be recorded / reproduced.

[0007]

As described above, in a data recording / reproducing apparatus which allows a plurality of sector sizes, a different format is defined for each data having a different sector size, and signal processing for recording / reproducing is performed. It was usual to make each format independent. This method has a problem that the scale of hardware for recording / reproduction increases. As another method, data of different sector sizes are basically recorded / reproduced in the same format, and an identification signal is put in a directory area or a header area, which is additional information, and the sector size is determined by this identification signal. There is a way to recognize.

The method of inserting the sector size identification information into the additional information has an advantage of allowing the hardware to be partially shared. However, there is a problem in terms of accessibility. In general, when recording / reproducing digital data, it is common to subject the data to digital modulation such as EFM in order to improve the error rate and facilitate clock extraction. The additional information is also modulated. Therefore, at the time of reproduction, unless demodulation processing is completed, the identification information cannot be obtained, the sector size of the data reproduced up to that time cannot be known, and accessibility is impaired.

Therefore, an object of the present invention is to reduce the scale of hardware when processing two or more data structures having different predetermined units of data such as a sector size.
An object is to provide a data recording / reproducing apparatus and method, and a disk medium that can improve accessibility.

[0010]

To achieve the above object, the present invention provides a data recording apparatus for recording digital data on a data recording medium,
The recording processing circuit has a recording processing circuit capable of processing digital data divided by predetermined units of two or more different sizes, and the recording processing circuit digitally modulates the error correction code encoder and the error correction coded data. Data having a modulation circuit and a synchronization signal addition circuit to which an output signal of the modulation circuit is supplied, and using the synchronization signal added by the synchronization signal addition circuit to identify the size of a predetermined unit It is a recording device. The present invention is also a recording method for recording data as described above.

Further, the present invention is a data recording medium on which data is recorded by digital-modulating error-correction-encoded digital data divided by predetermined units of two or more different sizes and adding a synchronizing signal. In the data reproducing apparatus for reproducing the data, a reproduction processing circuit to which the reproduced data is supplied is provided, and the reproduction processing circuit includes a sync signal separation circuit, a demodulation circuit for demodulating digital modulation, and an error correction code decoder. A data reproducing apparatus characterized in that the size of a predetermined unit of reproduced data is identified by the synchronizing signal separated by the synchronizing signal separating circuit. The present invention is also a reproducing method for reproducing data as described above.

Further, the present invention is data obtained by error-correcting coded digital data segmented by two or more predetermined units of different sizes, digitally modulating it, and adding a synchronizing signal. The data recording medium is characterized in that data that can be identified by a signal is recorded.

[0013]

Different sector sizes can be identified by the pattern of the synchronizing signal added after digital modulation. At the time of reproduction, the sector size of the reproduction data can be immediately known by separating the synchronization signal before digital demodulation. Therefore, it is possible to use a common data format other than the pattern of the synchronization signal, and further improve the accessibility.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an optical disc recording / reproducing system according to the present invention. This embodiment has a host computer 1, a CD-ROM drive 2 connected to it, and a drive for a high-density optical disc 3.
The high-density optical disc 3 is a CD or C that has already been put to practical use.
This refers to a large-capacity recordable / reproducible optical disc having a higher recording density than that of a D-ROM, and the recordable type (magneto-optical type or phase change type disc) of the DVD currently proposed is This is an example. Higher density can be achieved by shortening the wavelength of the laser, increasing the NA of the objective lens, and improving the digital modulation (for example, digital modulation in which the coupling bit in the EFM can be omitted). This optical disk drive has a configuration after the interface indicated by 4.

It should be noted that, unlike the example of FIG. 1, the CD-ROM drive 2 and the high-density optical disk drive are not separate hardware, but disk rotation drive, optical pickup, optical pickup thread mechanism, servo system, etc. It is also possible to share the disk control unit and the like and share the drive as hardware.

The data structure of the CD-ROM and the high-density optical disk 3, particularly the data unit for access (recording or reproduction) will be described. The CD-ROM is a development of the well-known CD (digital audio disc DAD). As shown in FIG. 2, a CD has a 1-byte subcode, 24-byte data, 4-byte C1 parity and 4-byte C1 parity in each transmission frame (also referred to as an EFM frame or C1 frame). It is arranged. On the CD, each byte is converted into a code word of 14 channel bits by EFM modulation and recorded via a combined bit (3 channel bits). Furthermore, at the beginning of each transmission frame, 11T
The inversion interval of (T is the cycle of the channel bit) is continuous, and after that, a sync (meaning a synchronization signal) of a total of 24 channel bits in which 2 channel bits are added is added.

The sub-code is constructed so that it becomes one unit with a cycle of 98 transmission frames. Therefore, the CD
In the DA, user data of 24 bytes x 98 = 2352 bytes is included in the 98 transmission frame.

C based on the transmission format of this CD
The data structure of the D-ROM is specified. That is,
The CD-ROM has an access unit of 2352 bytes, which is data included in 98 frames of the subcode cycle. This access unit is also called a block,
In the following description, it will be referred to as a sector. FIG.
The data structure of one sector of the CD-ROM is shown.

In the CD-ROM, mode 0, mode 1,
Mode 2 is specified. In common with these modes, a sync (12 bytes) and a header (4 bytes) indicating sector delimiters are added. In mode 0, data other than these syncs and headers is all "0", and is used as dummy data. FIG. 3 shows the data structure of one sector in mode 1 and mode 2. The header is CD
The sub-code consists of 3 bytes of address information and 1 byte of mode information.

In the data structure of mode 1, user data is 2,048 (2K) bytes, and auxiliary data of 288 bytes is added to enhance the error correction capability. That is, error detection code (4 bytes), space (8 bytes equivalent), P parity (172 bytes), Q
Parity (104 bytes) is added. Mode 1
Is suitable for recording data that requires high reliability, such as character codes and computer data.
In mode 2, 288 bytes of auxiliary data are not added,
Therefore, this mode allows recording of 2,336 bytes of user data. Mode 2 is suitable for recording data such as video data and audio data that can interpolate errors.

Further, CD-I is standardized as a ROM disk similar to the CD-ROM. FIG. 4 shows C
The data structure of one sector of DI is shown. Similar to the CD-ROM, a 12-byte sync and a 4-byte header are added, and the mode information in the header is mode 2. Four
In CD-I, an 8-byte subheader is added after the byte. The subheader consists of a 2-byte file number, a channel number, a submode, and a data type.

Further, as in the modes 1 and 2 of the CD-ROM, the forms 1 and 2 are defined in the CD-I. In Form 1, a 4-byte error detection code, 172-byte P parity, and 104-byte Q parity are added. Since no space is provided in the mode 1 of the CD-ROM, the area for user data is 2.
It is 048 bytes. In the form 2, a reserve area (corresponding to 4 bytes) is provided, and the area of user data is 2,324 bytes.

In this embodiment, the sector size (amount of user data) is set to 2 Kbytes when considered as an external storage medium of a computer. The data structure of one sector of the high density optical disc 3 in this embodiment is shown in FIG. 5A. A data sync (4 bytes) and a header (16 bytes) are added to 1 sector of 2,048 bytes of user data, and an error detection code EDC (4 bytes) is added to improve reliability. It Therefore, the length of one sector is 2,072 bytes.

On the other hand, since the user data of the above-mentioned CD-ROM in mode 2, for example, is 2,336 bytes,
As shown in FIG. 5B, a data sync (4 bytes) and a header (16 bytes) are added, an error detection code EDC is further added, and a CD-ROM header (4 bytes) is added.
To save. In this case, the size of the user data may be treated as 2,340 bytes without saving the header of the CD-ROM. Therefore, the length of one sector is 2,368
It is a byte. Preferably, the data sink and header and the error detection code EDC are shown in FIGS. 5A and 5A.
High-density optical disk data and CD-R shown in B respectively
The common one with the OM data is used.

As described above, the lengths of one sector are different, and there is no relation of integer ratio. In this embodiment, when two different sector sizes are A and B, nA and mB (n and m are integers, and n ≠).
The block is defined so that m, n> m) is contained in a data unit (referred to as a block) of a predetermined size. Data is recorded / reproduced (that is, accessed) in block units. As a method of defining n and m, a method of considering to be configured by m = n−1 and a method of n = 2
There is a method of configuring with ^j (j is a natural number). The method of defining m = n-1 is adopted when the block size is minimized. The method of defining n = 2 ^j is adopted when considering affinity with a computer system.

In the above example, considering only user data, if n = 8 and m = 7 are defined, 2048 bytes × 8 = 16,384 bytes, 2336 bytes × 7 = 16,352 bytes, and 16 Kbytes (16 , 384) fits in a block of bytes.

Further, as shown in FIG. 5 described above, considering a total of 20 bytes of the data sync and the header as a sector size, A '= 2,072, B
Since ′ = 2,368, n = 8 and m = 7 are selected,
The block size is 2,072 × 8 = 2,368 × 7 = 16,576 bytes, and the same common block size can be specified.

The data structure of one block in this case is (148 × 112 = 16,57) as shown in FIG.
By defining a two-dimensional array of 6 bytes) and applying an error correction code to this two-dimensional array, the error correction capability can be enhanced. As the error correction code, the first error correction code (referred to as C1 code) is encoded with respect to 162 bytes in the vertical direction (each column), and 8
A convolutional double code that generates C1 parity from bytes, encodes a second error correction code (referred to as C2 code) to 156 bytes in the diagonal direction, and adds C2 parity of 14 bytes. Can be adopted.

Of course, as the error correction code, other than this, a product code, a block completion type double coding, an LDC (Lon
g Distance Code) or the like may be adopted, and it is also possible to perform encoding using a simple error detection code.

The case where two different size sectors are integrated into the same size block will be described more specifically with reference to FIG. FIG. 7A shows 2,071 shown in FIG. 5A.
The processing of the sector size in the case of 2 bytes is shown. This 1 sector is divided into R / W directions every 148 bytes, and 148 ×
A two-dimensional array of 14 = 2072 bytes is formed. Therefore, one sector of this array is included in eight in one block, and one block forms a data structure of eight sectors.

FIG. 7B shows the processing of the sector size in the case of 2,368 bytes shown in FIG. 5B. R for this 1 sector
Divide every 148 bytes in the / W direction, 148 × 16 =
A two-dimensional array of 2,368 bytes is formed. Therefore, one sector of this array is included in seven in one block, and one block forms a data structure of seven sectors. During recording / playback, 2,072 bytes or 2,368 bytes of data
A block count is provided and a block delimiter is determined by detecting 7 or 8 sector syncs. Not limited to this method, a block sync other than the sector sync may be added.

Further, the present invention is a CD-DA (Digital A
The data of the structure in the case of (udio) can be a block structure having the same size as that of the high density optical disk as described above. In the case of CD-DA, 2 in 98 transmission frames
352 bytes of user data are included. As shown in FIG. 8, a 4-byte data sync and a 12-byte header are added to the user data, whereby the size of one sector can be set to 2,368 bytes. Therefore, like the above-mentioned CD-ROM sector, seven CD-DA sectors can be accommodated in one block.

Returning to FIG. 1, a recording / reproducing circuit according to an embodiment of the present invention will be described. Digital data from the host computer 1 or the CD-ROM drive 2 is supplied to the formatting circuits 5a and 5b via the interface 4, for example, SCSI. These formatting circuits 5a and 5b divide the received digital data into sectors, add a data sync and a header, and perform error detection coding. That is, the formatting circuit 5a converts the received data into a sector structure having a size of 2,072 bytes as shown in FIG. 5A, and the formatting circuit 5b converts the received data to 2,368 as shown in FIG. 5B. Convert to a sector structure of size byte.

The output data of the formatting circuits 5a and 5b are selected by the switch circuit 6, and the blocking circuit 7 is selected.
Is supplied to. The switch circuit 6 is the interface 4
The switch circuit 6 is switched according to the data received by the interface 4 under the control of the ID signal output from the switch circuit 6. When the interface 4 receives the data to be recorded on the disk 3 from the host computer 1, the switch circuit 6 selects the output of the formatting circuit 5a, and when the interface 4 receives the data from the CD-ROM drive 2, the switch circuit is selected. 6 selects the output of the formatting circuit 5b. Further, as described later, an ID signal is supplied to the recording processing circuit 8 and a sync signal (sector sync, additional sync S1, C1 sync S2, sector sync S3 or S4, and block sync S5 for identifying the received data is provided. ) Is generated.

The block forming circuit 7 forms a block composed of 7 sectors or 8 sectors and encodes an error correction code for each block. The data from the blocking circuit 7 is supplied to the recording processing circuit 8. The recording processing circuit 8 performs processing of error correction coding, digital modulation, and sync addition, as will be described later. Recording (writing) data is generated from the recording processing circuit 8.

Recording data is supplied to the optical pickup 10 via the driver 9 and recorded on the high density optical disc 3. Recording is performed by magneto-optical recording or phase change. The optical disc 3 is driven by the spindle motor 11.
It is rotated by CLV (constant linear velocity) or CAV (constant angular velocity). The minimum unit of data recorded / reproduced by the optical pickup 10 is one block described above.
By read-after-write, the recorded data is immediately reproduced to check whether or not there is an error in the reproduced data, and when there is an error, writing is retried. Even when reading, if the read data is an error, the reading is performed again, and if the correct data cannot be read even after reading a predetermined number of times, inform the user to that effect,
Suspend the read operation.

The reproduced data read by the optical pickup 10 is supplied to a detector circuit 21 including an RF amplifier, a PLL circuit for clock extraction and the like. Detector circuit 21
Is supplied to the servo control circuit 22 and the reproduction processing circuit 23. The servo control circuit 22 is
The focus servo, the tracking servo of the optical pickup 10, the control of the feeding operation (seek), the laser power control during recording, and the like are performed. The reproduction processing circuit 23 performs sync separation, digital demodulation, and error correction processing as described later.

A block decomposition circuit 24 is connected to the reproduction processing circuit 23. In the block decomposing circuit 24, the reproduced data is divided into blocks and the error correction code of the blocks is decoded. The block decomposing circuit 24 performs a process reverse to the process of the block circuit 7 on the recording side, and the block decomposing circuit 24 outputs the sector structure data. Although not shown, a timing signal synchronized with the block sync detected by the reproduction processing circuit 23 is supplied to the block decomposition circuit 24. The format decomposition circuits 25a and 25b are connected to the block decomposition circuit 24. The output of the format decomposition circuits 25a and 25b is the switch circuit 2
Selected by 7.

The format decomposing circuit 25a performs a process reverse to that of the recording side formatting circuit 5a, and the format decomposing circuit 25b performs a process reverse to that of the formatting circuit 5b. The format decomposition circuit 25a cuts out 2,048 bytes of user data from the sector of the high-density optical disc 3 shown in FIG. 5A and detects an error. Format decomposition circuit 25
By b, user data of 2,336 bytes is cut out from the sector of the CD-ROM shown in FIG. 5B, and
An error is detected. Although not shown, the reproduction processing circuit 23 supplies a timing signal to the format decomposition circuits 25a and 25b.

Format decomposition circuits 25a and 25b
One of the user data cut out by the switch circuit 27
And is supplied to the interface 4. The switch circuit 27 is controlled by the ID signal from the reproduction processing circuit 23 and outputs the output of the circuit 25a or the circuit 25a which performs a process corresponding to the sector structure of the actually reproduced data.
Select the output of b. The ID signal is formed by determining the sector sync pattern. The reproduction data selected by the switch circuit 27 is supplied to the interface 4. In this way, the data reproduced from the optical disc 3 can be transmitted to the host computer 1 through the interface 4.

The embodiment of the present invention described above is a CD-RO.
The host computer 1 can take in the data read by the M drive 2. Along with this, CD-
It is possible to record (write) the data read by the ROM drive 2 or the data for the high-density optical disc generated by itself on the high-density optical disc 3. And
High-density optical disc data reproduced from the optical disc 3,
Alternatively, the data in the CD-ROM can be taken in by the host computer 1.

As described above, it is possible to record and reproduce one of the high-density optical disk data generated by the host computer 1 and the read data of the CD-ROM on the same optical disk 3. However, according to the present invention, the data area of the same optical disk is divided, one of them is allocated to an area (RAM area) for data for a high density optical disk, and the other is a CD-ROM.
The present invention can also be applied to a hybrid disc allocated to the area (ROM area) for the data. Even in this case, the data recorded in the two areas have the same block structure, which is advantageous in that the recording / reproducing process can be simplified.

An example of the recording processing circuit 8 in FIG. 1 will be described with reference to FIG. The data from the blocking circuit 7 is written in the semiconductor memory (RAM) 15. A parity generation circuit 16 and a memory control circuit 17 are provided in association with the memory 15 to generate an error correction code, for example, a convolutional double code parity described later. The data to which the parity is added is supplied to the digital modulation circuit 18.

As will be described later in detail, the digital modulation circuit 18 maps a 1-byte (8-bit) data symbol onto a 16-bit codeword, for example, according to a predetermined table, thereby modulating with a small DC component. Produces output. Of course, EFM in CD, 8-15 modulation for converting an 8-bit data symbol into a 15-bit codeword, and the like can be adopted as digital modulation. The output of the digital modulation circuit 18 is supplied to the sync addition circuit 19.

For the sync addition circuit 19, the additional sync S generated by the sync pattern generation circuit 20 is added.
1, C1 sync S2, sector sync S3 or S4, and block sync S5 are supplied. An ID signal and a timing signal such as a clock (not shown) are supplied to the sync generation circuit 20, and one of the sector syncs S3 and S4 is selectively generated by this ID signal. The sync addition circuit 19 adds an additional sync S1, a C1 sync S2, a sector sync S3 or S4, and a block sync S5. The output of the sync adding circuit 19 is supplied to the driver 9 in FIG. 1 and recorded on the optical disc 3 by the optical pickup 10. As will be described later, these syncs have peculiar bit patterns that do not appear in the modulated data.

In one embodiment of the present invention, the sector structure is identified by the sector syncs S3 and S4 having different bit patterns. That is, as the sector size including the data sync and the header, 2,072 bytes (FIGS. 5A and 7A) for the high density disc and 2,3 for the CD-ROM are used.
68 bytes (FIGS. 5B and 7B) are defined. In order to identify these two sector sizes, a sector sync S3 is added to the high density disc sector and a sector sync S3 is added to the CD-ROM sector.
Add 4.

FIG. 10 shows an example of the reproduction processing circuit 23. The reproduced data from the detector circuit 21 is supplied to the sync separation circuit 31, and the additional sync S1 and C1 sync S are added.
2, sector sync S3 or S4, and block sync S5 respectively corresponding sync detection signals S1 ', S2
', S3' or S4 ', and S5' are generated from the sync separation circuit 31. Although not shown, these sync detection signals are supplied to a timing generation circuit to generate various timing signals such as a sector cycle and a block cycle synchronized with the reproduction data.

Further, the sync detection signal S3 'or S4' corresponding to the sector sync is supplied to the ID signal generating circuit 36. The ID signal generation circuit 36 generates an ID signal corresponding to the detected sector sync (S3 or S4). As described above, the switch circuit 27 in FIG. 1 is controlled by this ID signal, and the format decomposition circuit 2
One of the output signal of 5a and the output signal of the format decomposition circuit 25b is selected.

A digital demodulation circuit 32 is connected to the sync separation circuit 31. By the process reverse to that of the digital modulation circuit 16, the data in which the code word is converted into the data symbol is generated from the demodulation circuit 32. The output data of the digital demodulation circuit 32 is semiconductor memory (RAM) 3
Written in 3. The error correction circuit 34 and the memory control circuit 35 are coupled to the memory 33. The error correction circuit 34 corrects the error in the reproduced data. The data read from the memory 33 and subjected to the error correction processing is supplied to the block decomposing circuit 24 shown in FIG.

An example of the error correction code used in the recording processing circuit 8 and the reproduction processing circuit 23 will be described.
FIG. 11 is a block diagram showing an error correction code encoding process performed by the memory 15, the parity generation circuit 16, and the memory control circuit 17 of the recording processing circuit 8. This error correction code is similar to the cross interleaved Reed-Solomon code (one example of convolutional double coding) adopted in CD.

The 148-byte input symbol is supplied to the C1 encoder 41. The output of the C1 encoder 41 (148 bytes of data symbols and C1 parity P of 8 bytes) is C through the delay circuit group 42 for interleaving.
2 is supplied to the encoder 43. The C2 encoder 43 forms a 14-byte C2 parity Q by encoding the [170, 156, 15] Reed-Solomon code. Further, in the C1 encoder 41, not only the data but also the C2 parity Q is C1 encoded. Therefore, the C2 encoder 43 transmits the C2 parity Q via the delay circuit group 42a.
Is fed back to the C1 encoder 41. Therefore, the C1 encoder 41 encodes the [170, 162, 9] Reed-Solomon code.

170 bytes from the C1 encoder 41 (148 bytes of data, 8 bytes of C1 parity, 1
4 bytes of C2 parity) is taken out as an output symbol through the arrangement changing circuit 44 including a delay circuit. This output symbol is supplied to the digital modulation circuit 18. The interleave length (also referred to as interleave constraint length or interleave depth) of this convolutional double coding corresponds to the maximum delay amount by the delay circuit and is 170 frames (the frame here is the C1 code sequence). It is the length and means two frames of the above-mentioned transmission frame).

The processing of the decoder corresponding to the encoder shown in FIG. 11 will be described with reference to FIG. The input symbol (170 bytes) from the digital demodulation circuit 32 is supplied to the C1 decoder 52 via the arrangement changing circuit 51. The array changing circuit 51 performs a process reverse to that of the encoder array changing circuit 44. The C1 decoder 52 uses [170, 16
2, 9] Decode the Reed-Solomon code.

The output of the C1 decoder 52 is the delay circuit group 53.
Is supplied to the C2 decoder 54 via. The C2 decoder 54 decodes the [170,156,15] Reed-Solomon code. Further, the decoded output of the C2 decoder 54 is supplied to the C1 decoder 56 via the delay circuit 55 for deinterleaving. Thus, C1 decoding, C2
The error-corrected 148-byte output symbol is extracted by the decoding and C1 decoding processes.

Recording data output from the recording processing circuit 8 will be described with reference to FIG. FIG. 13A shows recorded data for a high density disc. As shown in FIG. 7A, one sector (2,072 bytes) is divided for every 148 pieces of data, and by this convolutional double encoding, a parity P of 8 bytes and a parity Q of 14 bytes are used. Is added. Therefore, (148 + 22 =
170) data symbols are generated. This data symbol is equally divided into 85 data symbols. 85
Each data symbol is converted into 85 × 16 = 1,360 channel bits by digital modulation (8-16 modulation).

Then, with respect to the modulation data symbols in the first half, a sector sync S3 or C of 32 channel bits is used.
One sync S2 is added, and as a result, (1,360+
Data of one transmission frame of 32 = 1,392 channel bits) is configured. An additional sync S1 of 32 channel bits is added to the latter half modulated data symbol, and one transmission frame is similarly formed. As shown in FIG. 13A, (14 × 2 = 28) transmission frames form one sector of recorded data for a high density disc. The sector sync S3 is added to the leading transmission frame of the 28 transmission frames instead of the C1 sync S2.

FIG. 13B shows the recorded data of one sector for CD-ROM. (16 × 2 = 3) of a transmission frame of the same format as the recording data for the high density disc described above.
2) The recording data of one sector is constituted by the number of pieces.
C1 sync S for the beginning of this transmission frame
Instead of 2, a sector sync S4 is added.

One method for adding the block sync S5 is shown in FIG. 13C. As described above, one block is composed of 8 sectors for high-density disk or 7 C
It consists of sectors for D-ROM. Therefore, for the first transmission frame of the first sector in one block, the block sync S5 is used instead of the sector sync S3 or S4.
Is added. The sector sync S3 or S4 is added to the leading transmission frame of another sector. The block sync S5 may be added independently of the sector sync.
Furthermore, the block sync may not necessarily be added, and by counting the number of sector syncs,
Block divisions may be detected.

Furthermore, in the above-described embodiment, since S1 and S2 are prepared as the sinks for the transmission frame, the sector structure can be identified by utilizing them. That is, as shown in FIG. 22A, in the recording data for the high density disc, only the additional sync S1 is used as the sync for the transmission frame. On the other hand, C
In the recording data for D-ROM, as shown in FIG. 22B, only the C1 sync is added to each transmission frame. By doing so, the sector can be identified from the pattern of the sync at the beginning of each transmission frame. FIG. 22C shows the structure of the recording data of the entire block. In the example of FIG. 22, the sector sync is not necessarily S3.
It is not necessary to use both S4 and S4.
The sector sync S4 of B may be replaced by the sector sync S3.

FIG. 14 shows a concrete bit pattern of the sync. As a digital modulation method, (8-1
6) Shows a sync bit pattern when modulation (called EFM plus) is adopted. State 1, 2 and 3 described later
And 4 are related to the (8-16) modulation scheme, and the bit pattern of the sync in states 1 and 2 and the bit pattern of the sync in states 3 and 4 are defined, respectively. Most significant bit (msb) is "0"
Is the state 1 and 2 and the case of "1" is the state 3
And 4. The transmission frames are sequentially inserted from msb.

The bit patterns of the additional sync S1, C1 sync S2, sector sync S3 or S4, and block sync S5 are different from each other as shown in FIG. 14, and these bit patterns are codes obtained by modulating data symbols. It does not appear in the word sequence. More specifically, it can be seen that it is a sync word by including a pattern in which two inversion intervals of 11T (T: a bit cell of a channel bit) are continuous.

The above (8-16) modulation will be described below. This modulation method converts each input 8-bit data symbol into a 16-channel-bit codeword and directly combines this codeword with the next codeword, that is, the combined (or margin) bits in the EFM. It is the one that connects without intervening.
A part of the conversion table for converting the data symbols into the codewords is doubled. In this doubled part, corresponding sets of codes have mutually opposite digital thumb variation variations and absolute values. The values are close to each other.

FIG. 15 shows an example of such a conversion table. As shown in FIG. 15, there are plural types of conversion tables, for example, four types of unit tables T ₁ , T ₂ , and T.
₃ and T ₄ , and each unit table has a duplicated portion. That is, when a table of a set of codewords for all data symbols in one unit table is Ta, a part of the table is duplicated into a table Tb. In the specific example of FIG. Eighty-eight parts with values of 0 to 87 are duplicated. In the following description, the table Ta will be referred to as a front table and the table Tb will be referred to as a back table.

In the specific example of FIG. 15, four types of tables (table tables) T _1a , T _2a , T _3a , T of 256 codewords corresponding to 8-bit data symbols 0 to 255 are provided.
_4a and tables T _1b , T _2b , T _3b , and T _{4b in} which portions 0 to 87 of the data symbols of tables T _1a , T _2a , T _3a , and T _4a are duplicated, respectively, A translation table is constructed. In this example, the duplication part of the conversion table, that is, the codeword of the part where the data symbols of the tables T _1a , T _2a , T _3a , and T _4a are 0 to 87, and the tables T _1b , T _2b , and T _3b , T
_With respect to the code word of _4b , the corresponding code word group is configured such that the variation amounts of the digital sum variations are opposite to each other and their absolute values are close to each other.

An embodiment of the modulation method using the conversion table of FIG. 15 will be described below. Also in this (8-16) modulation, the EFM condition (3T to 11T) that the number of "0" s between "1" and "1" is 2 or more and 10 or less.
Satisfy the rules). In the EFM, there is one type of table for converting data symbols into codewords, but in the (8-16) modulation method, several types of tables are provided for converting data symbols into codewords. In the example of FIG. 15, four types of unit tables T ₁ , T ₂ ,
T ₃ and T ₄ are used. Here, the “state value” used for classifying the unit table will be described.

This state value serves as an index for deciding which conversion table should be used when converting a data symbol into a codeword.
Therefore, the number of state values is equal to the number of unit tables in the conversion table. That is, in this example, there are four state values (“1” to “4”) corresponding to the four types of unit tables T ₁ , T ₂ , T ₃ , and T ₄ , respectively.

The state value changes each time one data symbol is converted into a codeword. Codeword is "1"
When it ends in or ends in "10", the state value changes to "1". When the codeword ends with two or more and five or less consecutive "0" s, the state value changes to "2" or "3". If the codeword ends in 6 or more and 9 or less consecutive "0" s, the state value changes to "4".

The table for converting data symbols into codewords has the following features. State value is "1"
Unit table T ₁ used when
Since it satisfies the condition (3T-11T rule) that the number of "0" s between 1 and "1" is 2 or more and 10 or less, it consists of at least two codewords starting with "0". It This is because the codeword modulated before the state value changes to "1" ends with "1" or "10".

For the same reason, the unit table T ₂ or T ₃ used when the state value is “2” or “3” includes only 0 to 5 consecutive codewords starting with “0”. In the unit table T ₂ used when the state value is “2”, both the first bit and the 13th bit are “0” when the MSB is the first bit. The unit table T ₃ configured by a code and used when the state value is “3” has the first bit and the 1
Either or both of the third bits are "1". The unit table T ₄ used when the state value is “4” is composed only of codewords starting with “1” or “01”.

Here, there is a codeword that can be commonly used for two different state values. For example, for a codeword that starts with three consecutive "0" s and the first and thirteenth bits are "0", the status value is "1".
It can be used even when the status value is "2". Considering the case of decoding such a code, it is necessary to configure the table so that the values of the data symbols are the same.

Further, the type of codeword whose state value changes to "2" or "3" next time can be assigned to two completely different values of the data symbol. In such a case, just from that code,
Decoding cannot be performed uniquely, but by setting the value of the next changing state value to "2" for one and "3" for the other, this can be decoded correctly. become. This method will be described later.

Furthermore, for each code of all unit tables, it indicates which of the following state values changes from "1" to "4" when the data symbol is converted to that code. Provide one table. When the codeword ends with 2 or more and 5 or less consecutive "0" s, it is not possible to determine only whether the state value changes to "2" or "3" from the characteristics of the code. However, the next state value can be uniquely determined by referring to this table. After the sync pattern, the state value is always "1". In the example of FIG. 15, the next state value is indicated by S, and a table including these state values S in the changing direction is configured.

Using these tables, the modulator
Converts a bit data symbol to a codeword. The current state value is stored in an internal memory, a table to be referred to is obtained from the state, and modulation is performed by converting an 8-bit signal into a code word in the table. At the same time, the next state value is obtained from the table and stored so that the table to be referred to when performing the next conversion can be obtained.

Next, control of DSV (digital sum variation or digital sum value) will be described.
For each of the above state values, the run length limit (3T to
11T rule) and consider how many codewords can be used without problems. At this time, ten “0” s are arranged in order to prohibit the occurrence of a two-time repeated pattern of 11T, which is the same as the sync pattern. Codewords that end in a row of five "0s" after the subsequent "1" are removed in advance. 5 after this code
This is because, when codewords in which “0” s start in succession are combined, a 2T repeating pattern of 11T occurs. Further, when the state value changes to "2" or "3" after conversion into a codeword, the code can be used in two ways, so these codes are counted twice.

When this is calculated, 344 codewords can be used when the state value is "1", 345 codewords can be used when the state value is "2", and the state value is "3". There are 344 codewords that can be used when the status value is “4”, and 411 codewords that can be used when the state value is “4”. Since the input data symbol is 8 bits, it suffices that there are 256 kinds of codes, and at least 88 for each state value.
The street code will be left over. Therefore, the extra code of 88 is used for controlling the DSV. That is, a table with 88 entries, a so-called back table, is separately provided by using the remaining symbols. In this example, this back table is configured for data symbols whose data symbols are "0" to "87".

Here, in this DSV control method, in order to perform the DSV control most efficiently, the configuration policies of the front and back tables are as follows. As described above, there are codewords that can be commonly used for two different state values. With these codes, it is necessary to configure the table so that the values of the data symbols are always the same.
The way tables are organized is actually quite complicated. Here, since the purpose is to show the method of constructing the table for efficiently controlling the DSV, for simplification, each state value is considered independently, and the codeword that can be used in each state value is It is assumed that the value can be freely assigned.

FIG. 16 is a flow chart for explaining the method of constructing the conversion table as described above, more specifically, the method of constructing any one of the four types of unit tables of the conversion table. In FIG. 16, in step S101, the previous pattern of the codeword is obtained, and in the next step S102, a bit pattern or code satisfying the condition of the run length limitation (3T to 11T) is selected. In the next step S103, the codes are classified according to the conditions for each state value described above. As described above, there are 344 to 411 codewords that can be used for each state value. For example, there are 344 codewords that can be used when the state value is “1”.

Next, in step S104, the amount of change in the DSV when the immediately preceding level (= CWLL) is the low level is calculated for all the codes for each state value. Considering that the code length is 16 bits and there is a run length limitation (3T to 11T),
The change amount of DSV per code is -10 at the minimum and +10 at the maximum. When the state value is “1”, for example, the minimum value is −10 and the maximum value is +6.

In the next step S105, for example, 344 codewords in the case where the above state value is "1" are set to D
The SV variation is arranged in order from the largest in the positive direction to the largest in the negative direction. So-called sort.

Next, in step S106, DS
Eighty-eight codewords are selected in order from the one in which the amount of change in V is large in the positive direction. For example, from the data symbol “0” in the table T _1a shown in FIG. 17 when the state value is “1”. It is sequentially assigned to "87". On this occasion,
Among the 88 selected codewords, the larger absolute value of the change amount of DSV is assigned to the smaller value of the data symbol. Further, 88 codewords are selected in order from the one having the largest amount of change in DSV in the negative direction, and are assigned to, for example, data symbols “0” to “87” in the table T _{1b on} the back side of FIG. At this time, among the 88 selected codewords, the larger the absolute value of the change amount of the DSV, the smaller the value of the data symbol. Finally, in order from the smallest absolute value of the change amount of DSV, 1
Sixty-eight codewords are selected and assigned to data symbols “88” to “255” in the table T _1a of the table of FIG. 17, for example.

Actually, when the state value is "1",
As shown in FIG. 17, there are 344 available codewords.
That's right, so all the codes that can be used at this stage will be selected. Also, an example of allocation of data symbols in each unit table of the conversion table used when the state values are “2”, “3” and “4”,
These are shown in FIGS. 18, 19 and 20, respectively.

In these FIGS. 17 to 20, the order of codewords having the same amount of change in DSV when applying the sorting is different from that of the example of FIG. 15, but any table is used. But there is no problem.

By constructing the front table Ta and the back table Tb with such a configuration policy, when the data symbol has a value between "0" and "87", D
Since it is possible to select one of the two codewords having a relatively large absolute value of the change amount of SV and opposite polarities, it is possible to efficiently perform the DSV control. In addition, the data symbols are "88" to "25
If the value is between 5 ", the codeword cannot be uniquely determined and the DSV control cannot be performed. However, these codewords are selected so that the absolute value of the change amount of the DSV is relatively small. Therefore, the absolute value of the cumulative DSV can always be kept small.

The back table Tb having 88 entries as defined here has exactly the same characteristics as the front table Ta having 256 entries, except that the number of entries is small. Using this back table Tb together with the front table Ta, D
SV is controlled. Data symbols are "0" to "8"
If it is between 7 ", it is possible to appropriately select whether to use the front table Ta or the back table Tb when converting the data symbol into the code word. Therefore, in this example, DSV in conventional EFM
As in the case of control, the cumulative DSV is always calculated, and the cumulative DSV when the conversion is performed by using the front table Ta and the cumulative DSV when the conversion is performed by using the back table Tb are obtained, respectively. Perform the conversion while selecting the one whose absolute value of is closer to zero.

Next, an algorithm of the signal modulation method using the conversion table having such a configuration will be described with reference to FIG. When the data symbol is input in step S1, the current state value is acquired in step S2, and then the value of the 8-bit data symbol is changed to 8 in step S3.
It is determined whether it is 7 or less.

If YES in step S3, that is, if it is determined that the number of data symbols is 87 or less, the process proceeds to step S4, and the table Ta of the table corresponding to the current state value is used.
, The code word corresponding to the data symbol is obtained, and the cumulative DSV value xa is calculated. Step S
In 5, the table Tb on the back corresponding to the current state value is referred to acquire the codeword corresponding to the data symbol,
Calculate the cumulative DSV value xb. In the next step S6,
It is determined whether the absolute values of the cumulative DSV values xa and xb are large or small, that is, whether or not | xa | ≦ | xb |.

If NO in step S3, that is, if the data symbol is larger than 87, the process proceeds to step S7, the table word Ta corresponding to the current state value is referred to, and the code word corresponding to the data symbol is obtained. It is acquired and it progresses to step S10. YES in step S6, that is, |
When it is determined that xa | ≦ | xb |, the table table T
The codeword is acquired with reference to a, and the process proceeds to step S10. If NO in step S6, that is, if it is determined that the absolute value of the cumulative DSV value xb of the code in the back table Tb is smaller, the back table Tb is referenced to acquire the codeword, and the process proceeds to step S10.

After the cumulative DSV is calculated and updated in step S10, the state value is updated by referring to the next state value table, that is, the table summarizing the next state value S in FIG. 15 in step S11. To do. In the next step S12, the acquired codeword is output.

(8-16) modulation is performed as described above. To repeat, the present invention is (8-1
6) Not limited to modulation, it can be applied to digital modulation methods such as EFM and (8-15) modulation.

The above-mentioned block size of 16 Kbytes, which is a set of a plurality of sectors, is an example, and other block sizes such as 32 K may be adopted in consideration of applications and the like. Is. Further, according to the present invention, it is not necessary to integrate different sector sizes into blocks of the same size, and the present invention can be applied to a case where a plurality of types of block sizes are supported. Further, the present invention can be applied not only to the disk-shaped recording medium but also to the case where a large capacity semiconductor memory is used as the data recording medium.

[0091]

According to the present invention, the sector size can be identified by the bit pattern of the sync when it corresponds to data of different sector sizes. Therefore, the sector size can be identified at the time of reproduction before demodulation and decoding, and access corresponding to each block becomes possible, and accessibility can be improved. Further, the present invention can realize a disc drive capable of recording / reproducing discs of two different formats, a hybrid disc having data of two different formats recorded, and the like.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a recording / reproducing circuit according to the present invention.

FIG. 2 is a schematic diagram for explaining a data structure of a conventional CD.

FIG. 3 is a schematic diagram for explaining a data structure of a conventional CD-ROM.

FIG. 4 is a schematic diagram for explaining a data structure of a conventional CD-I.

FIG. 5 is a schematic diagram showing an example of two data structures of a sector in an embodiment of the present invention.

FIG. 6 is a schematic diagram showing a data structure of a block in one embodiment of the present invention.

FIG. 7 is a schematic diagram showing a relationship between sectors and blocks in an embodiment of the present invention.

FIG. 8 is a schematic diagram showing another example of the data structure of the sector in one embodiment of the present invention.

9 is a block diagram of an example of a recording processing circuit in FIG.

10 is a block diagram of an example of a reproduction processing circuit in FIG.

FIG. 11 is a block diagram illustrating an example of error correction coding processing in a recording processing circuit.

FIG. 12 is a block diagram showing an example of a process of decoding an error correction code in the reproduction processing circuit.

FIG. 13 is a schematic diagram for explaining a transmission frame of recording data and a sync to be added.

FIG. 14 is a schematic diagram showing a specific example of a sink to be added.

FIG. 15 is a schematic diagram showing an example of a conversion table for (8-16) modulation, which is one of the digital modulation methods that can be adopted in the present invention.

FIG. 16 is a flowchart showing an example of an algorithm that forms a conversion table for (8-16) modulation.

FIG. 17 is a schematic diagram showing an example of a unit table when the state value is “1”.

FIG. 18 is a schematic diagram showing an example of a unit table when the state value is “2”.

FIG. 19 is a schematic diagram showing an example of a unit table when the state value is “3”.

FIG. 20 is a schematic diagram showing an example of a unit table when the state value is “4”.

FIG. 21 is a flowchart for explaining (8-16) modulation processing.

FIG. 22 is a schematic diagram for explaining a modified example of a transmission frame of recording data and an added sync.

[Explanation of symbols]

 1 Host Computer 2 CD-ROM Drive 3 High Density Optical Disk 4 Interface 5a, 5b Formatting Circuit 7 Blocking Circuit 8 Recording Processing Circuit 18 Digital Modulation Circuit 19 Sync Addition Circuit 23 Reproduction Processing Circuit 24 Block Decomposition Circuit 25a, 25b Format Decomposition Circuit 31 sync separation circuit 32 digital demodulation circuit

Claims (7)

[Claims] 1. A data recording device for recording digital data on a data recording medium, comprising a recording processing circuit capable of processing digital data divided into predetermined units of two or more different sizes. The recording processing circuit includes an error correction code encoder,
A modulation circuit for digitally modulating the error-correction-coded data and a synchronization signal addition circuit to which the output signal of the modulation circuit is supplied are provided, and the synchronization signal added by the synchronization signal addition circuit is used to A data recording device characterized by identifying a size of a predetermined unit. 2. Data for reproducing a data recording medium on which data obtained by error-correcting coded digital data segmented by predetermined units of two or more different sizes, digitally modulated, and adding a sync signal is recorded. The reproducing apparatus has a reproducing processing circuit to which reproduced data is supplied, and the reproducing processing circuit has a synchronization signal separation circuit, a demodulation circuit for demodulating digital modulation, and an error correction code decoder, A data reproducing apparatus characterized in that the size of the predetermined unit of reproduced data is identified by the synchronizing signal separated by the synchronizing signal separating circuit. 3. A data recording method for recording digital data on a data recording medium, comprising a recording processing step capable of processing digital data divided into predetermined units of two or more different sizes. However, the step of the recording processing includes an error correction code encoding step, a modulation step of digitally modulating the error correction coded data, and a step of adding a synchronization signal to the modulated signal, A data recording method, wherein the size of the predetermined unit is identified by using the added synchronization signal. 4. Data for reproducing a data recording medium on which data obtained by error-correcting coded digital data divided by predetermined units of two or more different sizes, digitally modulated, and adding a sync signal is recorded. The reproducing method includes a reproducing process step of processing reproduced data, and the reproducing process step includes a step of separating a synchronization signal, a step of demodulating digital modulation, and a step of decoding an error correction code. A data reproducing method, characterized in that the size of the predetermined unit of the reproduced data is identified by the synchronizing signal separated by the synchronizing signal separating circuit. 5. Data obtained by error-correcting coded digital data segmented by two or more predetermined units of different sizes, digitally modulating it, and adding a sync signal, said size being determined by said sync signal. A data recording medium on which data that can be identified is recorded. 6. The data recording / reproducing apparatus and method according to claim 1, claim 2, claim 3, claim 4, or claim 5, wherein the predetermined unit is a sector. Data recording medium. 7. The data recording / reproducing apparatus according to claim 1, claim 2, claim 3, claim 4, or claim 5, wherein the predetermined unit is a block including a plurality of sectors. , And method,
And data recording medium.