JP2004164691A - Modulating device, modulation method, record medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a digital information signal recorded on an original record medium from being copied. <P>SOLUTION: When a code word sequence is generated by converting input data words D of p bits into code words C of q bits and adding a merge bit 1b of r bits in order to obtain the best DSV value between adjacent code words C and D, a modulating device 30 is offered. The modulating device is characterized in that it does not strictly comply with the minimum run length (d+1) T - the maximum run length (k+1)T established for code word sequence based on the run length restriction regulations RLL (d, k) but instead, adds the merge bit 1b of r-bits between the code words C and C in order to permit the minimum run length (d+1) T - the maximum run length (k+2) T. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a modulation device, a modulation method, and a recording medium for preventing copying of a digital information signal recorded on a recording medium such as an optical disk or a digital magnetic tape.
[0002]
[Prior art]
With the advent of the age of digital multimedia, large-capacity digital information signals are recorded on optical disks or digital magnetic tapes.
[0003]
For example, a read-only optical disk such as a CD (Compact Disc) containing music information or a CD-ROM (CD-Read Only Memory) containing computer data is formed in a spiral or concentric shape on a disk-shaped disk substrate. The above-mentioned digital information signals can be recorded at high density on the tracks formed in this manner, and the desired tracks can be accessed at high speed during reproduction, and are suitable for mass production and can be obtained at low cost.
[0004]
Digital magnetic tapes containing PCM music information and the like are widely used because they can be reproduced for a longer time than optical disks.
[0005]
In the following description, an optical disk that records and / or reproduces data using an optical pickup as a recording medium for recording digital information signals will be described. However, in the case of a digital magnetic tape, when recording and / or reproducing data, The only difference is that a head is used. Therefore, a description of a digital magnetic tape will be omitted.
[0006]
Optical discs such as the CDs and CD-ROMs described above convert a digital information signal into a digital pit row with concave pits and convex lands, and carve this pit row as a spiral or concentric recording track. After the stamper board on which the signal surface has been recorded is mounted in an injection molding machine, the signal surface of the stamper board is 120 mm or 80 mm in outer diameter using a transparent resin material, the hole diameter of the center hole is 15 mm, and the substrate thickness is 1.2 mm. It is transferred to a disk-shaped transparent disk substrate, and a reflective film and a protective film are sequentially formed on the transferred signal surface to form a read-only type.
[0007]
When reproducing a read-only optical disk, a laser beam for reproduction from an optical pickup movably provided in the optical disk drive was irradiated onto the signal surface from the transparent disk substrate side to form a film on the signal surface. The signal surface is reproduced by the return light of the laser beam from the reflection film.
[0008]
By the way, music information recorded on CDs and computer data recorded on CD-ROMs are protected by copyright law, but since they are digital information, there is no signal deterioration. The user can copy to a write-once optical disc such as a CD-R (Compact Disc-Recordable) that can be written only once without permission of the copyright holder, or a CD-RW (Compact Disc-ReWritable) that can be written multiple times. It is possible to do.
[0009]
The write-once optical discs such as the CD-R and CD-RW described above have substantially the same external appearance as read-only optical discs such as CDs and CD-ROMs, but have spiral grooves formed on a transparent disc substrate. Alternatively, the recording layer is formed concentrically, an organic dye serving as a recording layer is spin-coated on the concave groove side, and a reflective film and a protective film are sequentially formed on the organic dye. Moreover, it is available at low cost.
[0010]
Then, when music information recorded on a CD or computer data recorded on a CD-ROM is copied to a CD-R or CD-RW, it is recorded in the same signal format as the CD or CD-ROM. This infringes copyright.
[0011]
Hereinafter, a code word string of music information recorded on a known CD will be described. FIGS. 1A and 1B are diagrams for explaining a signal format of music information recorded on a CD. FIG. 1A shows original music data, FIG. 1B shows an EFM signal, and FIG. A diagram showing an encoding table at the time of modulation,
FIGS. 3A and 3B are diagrams for explaining DSV control at the time of 8-14 modulation.
[0012]
First, music information is recorded on a CD in a signal format conforming to the CD standard book “Red Book” or the IEC (International Electrotechnical Commission) 908 standard.
[0013]
In this case, generally, the pit length recorded on the optical disc is limited by the minimum run length (minimum pit length or minimum land length) due to the optical transmission characteristics of recording / reproduction and physical constraints related to pit generation, clock reproduction. In order to limit the maximum run length (maximum pit length or maximum land length) from the ease of operation, and to protect the servo band, etc., the recording signal must have a low-frequency component and a DC component suppression characteristic of the recording signal. It needs to be modulated.
[0014]
Among the modulation schemes satisfying this restriction, the EFM (Eighth Fourteen Modulation: 8-14 modulation) scheme used for CDs has a minimum run length of 3T (T = cycle of channel bits) and a maximum run length of 11T. Things.
[0015]
That is, as shown in FIG. 1A, the music original data AD to be recorded on the CD is digital data, and upper 8 bits (1 byte) + lower 8 bits (1 byte) = 16 bits (2 bytes) and 1 bit. A unit is constituted, and the music original data AD is constituted by a plurality of these one units.
[0016]
When the original music data AD shown in FIG. 1A is recorded on a glass master by a laser beam at the time of mastering, the original music data AD is converted into an EFM signal format so as to have a signal form suitable for recording. Then, it is recorded on the glass master in the form of the EFM signal 1 shown in FIG. 1 (b), and thereafter, a metal master board, a mother board, and a stamper board are sequentially manufactured by electroforming based on the glass master. Thereafter, the stamper board is mounted in the injection molding machine, and the signal surface of the stamper board is transferred to the transparent disk substrate to produce a CD. Therefore, the signal surface of the CD is equivalent to the signal surface of the glass master disc.
[0017]
Here, in the format of the EFM signal 1 described above, the input music original data AD is divided into an upper 8-bit input data word D and a lower 8-bit input data word D, and the encoding table shown in FIG. Referring to the input data word D of p bits = 8 bits, a run length limited code of q bits = 14 bits (hereinafter referred to as “q bits = 14 bits”) satisfying a predetermined run length restriction rule that the minimum run length is 3T and the maximum run length is 11T. , Codeword C), and as shown in FIG. 1 (b), between the converted codeword C and the codeword C, for holding the run-length restriction rule and DSV (Digital Sum Value). The first and second code word strings 1d and 1f to be described later are generated as an EFM signal 1 by adding r bits = 3 combination bits 1b for control. To have.
[0018]
At this time, when a predetermined run length restriction rule is satisfied, the minimum run length is 3T, and the number of “0” s between the logical values “1” and “1” in the code word C is at least d = 2. On the other hand, when the maximum run length is 11T, at most k = 10 “0” s are included between logical values “1” and “1” in the code word C. In other words, when the run length restriction rule RLL (d, k) = RLL (2,10) is satisfied, the minimum run length is determined based on the run length restriction rule RLL (d, k) = RLL (2,10). (D + 1) T = 3T, and the maximum run length is set to (k + 1) T = 11T. The first and second codeword strings 1d and 1f, which are obtained by adding a 3-bit combination bit 1b between adjacent codewords C and C, have a minimum run length (d + 1) T = 3T to a maximum run length ( k + 1) T = 11T, and when the NRZI conversion is performed on the first and second codeword strings 1d and 1f as described later, the minimum run length 3T is the minimum inversion interval, while the maximum The run length 11T indicates the maximum inversion interval.
[0019]
The pfm modulation = 8-14 modulated EFM signal 1 satisfies the run length restriction rule RLL (d, k) = RLL (2,10) in which the minimum run length is 3T and the maximum run length is 11T. However, the DC component and the low frequency component of the EFM signal 1 can be reduced.
[0020]
Further, NRZI (Non Return to Zero Inverted) conversion is performed on the EFM signal 1 including the first and second codeword strings 1d and 1f. As is well known, the NRZI conversion has a polarity at bit "1". Since the modulation is performed without inverting the polarity at bit “0”, the waveform after the NRZI conversion becomes the recording signal R on the glass master, and the L (low) level section of the recording signal R is For example, a pit row is formed so as to correspond to a concave pit (or a convex land), and the H (high) level section in the recording signal R corresponds to, for example, a convex land (or a concave pit).
[0021]
As shown in FIGS. 3A and 3B, the above-mentioned DSV has a waveform of H (high) level after the NRZI conversion from the start time of the codeword string in the EFM signal 1 to the present time. This is an integrated value obtained by integrating “1” (positive polarity) at time and “−1” (negative polarity) at L (low) level. At this time, in the NRZI conversion, since the polarity inversion is performed at the data bit “1”, even if the code word has the same bit pattern, it differs depending on the waveform state after the NRZI conversion immediately before connecting the code word. As shown in FIG. 3A, when the waveform state immediately before the input data word = 002 is at the L (low) level, and as shown in FIG. The DSV value is inverted when the waveform state is at the H (high) level. For example, when the input data word = 002 and the input data word = 253 are connected via a connection bit, FIG. The absolute value of both DSVs in FIG. 3B is the same.
[0022]
Here, as a 3-bit combined bit 1b between adjacent codewords C and C such that the absolute value of the DSV approaches substantially zero while satisfying the run-length restriction rule RLL (d, k) = RLL (2, 10). , (000), (001), (010), and (100) are selected and added to reduce the DC component of the waveform of the recording signal R, resulting in recording. When the waveform of the signal R is viewed over a long period, the H (high) level section and the L (low) level section appear at substantially the same ratio, so that the concave pit section and the convex land section also have substantially the same ratio. The DSV value is controlled to appear.
[0023]
Referring back to FIG. 1B, one frame of the EFM signal 1 described above includes a synchronization signal 1a, a combination bit 1b, a subcode 1c, a combination bit 1b, a first codeword string 1d, a combination bit 1b, and a C2 error correction from the beginning. The code 1e, the combination bit 1b, the second code word string 1f, the combination bit 1b, the C1 error correction code 1g, and the combination bit 1b are arranged in this order, and are composed of 588 channel bits in total for one frame.
[0024]
Here, the synchronization signal 1a arranged at the head can be identified from the above-mentioned signals 1b to 1g as 11T, 11T, and 2T signals in order to indicate the head of the frame using 24 bits.
[0025]
The subcode 1c arranged after the synchronization signal 1a via the 3-bit combination bit 1b is a signal for controlling reproduction to a CD.
[0026]
The first code word sequence 1d arranged via the 3-bit combination bit 1b after the sub-code 1c is obtained by encoding each input data word D (each music original data) of p = 8 bits as shown in FIG. Referring to the table, the codewords are converted into codewords C of q = 14 bits, and three codewords C (12 symbols) are added between adjacent codewords C. ) And 11 combined bits 1b.
[0027]
Further, the C2 error correction code 1e arranged after the first code word string 1d via the 3-bit combination bit 1b is converted into the first code word string 1d and the second code word string 1f of the EFM signal 1 during CD reproduction. The error correction is performed for this.
[0028]
Further, the second code word sequence 1f arranged via the 3-bit combination bit 1b after the C2 error correction code 1e has 12 code words C (12 symbols) like the first code word sequence 1d described above. And 11 combined bits 1b.
[0029]
Further, the C1 error correction code 1g arranged after the second codeword string 1f via the 3-bit combination bit 1b is used to output the first codeword string 1d, the second codeword string 1f, and C2 of the EFM signal 1 during CD reproduction. Error correction is performed on the error correction code 1e.
[0030]
Then, 98 blocks (= 98 frames) of NRZI-converted recording signals after one frame of the above-mentioned EFM signal 1 are continuously formed to constitute one block which is a unit of music. This corresponds to a period of 1/75 second.
[0031]
In the case of a CD-ROM containing computer data, the description is omitted because the music original data shown in FIG. 1A only needs to be renamed to the computer original data.
[0032]
Here, a conventional modulation device will be described with reference to FIGS.
[0033]
FIG. 4 is a block diagram schematically showing a conventional modulation device,
FIGS. 5 (a) to 5 (c) show a code obtained by adding a combination bit between one code word and the next code word while strictly observing a predetermined run length restriction rule using a conventional modulator. A description will be given of a state where DSV values of a plurality of sets of code word strings are calculated when (000), (001), (010), and (100) are temporarily added as connection bits when a word string is generated. FIG.
[0034]
The conventional modulation device 20 shown in FIG. 4 includes a glass master recording machine (not shown) for producing a CD, and a CD-R drive (not shown) for copying music information recorded on a CD to a CD-R. (Not shown), and has a schematic configuration of an 8-14 modulation circuit 21, a combination bit addition circuit 22, a DSV value calculation circuit 23, and a DSV value comparison circuit / combination bit selection circuit 24. Have been.
[0035]
Then, the conventional modulation device 20 separates the 16-bit music original data AD into upper 8 bits and lower 8 bits and converts each 8-bit input data word D into each 14-bit code word C. A plurality of sets of 3-bit combination bits 1b satisfying the run-length restriction rule RLL (2, 10) are temporarily added between one code word Cx and the next code word Cy. By generating a word string and selecting one set of code word strings whose absolute value of DSV is closest to zero from among the DSV values of the plurality of code word strings, the code word of this one set is obtained. The sequence is output as one finally determined code word sequence.
[0036]
More specifically, in the conventional modulation device 20, 16-bit music original data AD is input to the 8-14 modulation circuit 21 in chronological order.
[0037]
In the 8-14 modulation circuit 21 described above, the input music original data AD is converted into the upper 8 bits of the input data word D and the lower 8 bits of the input data word D as described earlier with reference to FIG. When each input data word D of 8 bits is sequentially converted into a code word C of 14 bits based on the encoding table shown in FIG. 2, for example, one code word Cx and one code word are separated. The next code word Cy following the word Cx is sequentially read. Then, one codeword Cx and the next codeword Cy are input from the 8-14 modulation circuit 21 to the combination bit addition circuit 22.
[0038]
Next, the combined bit addition circuit 22 strictly adheres to the minimum run length 3T to the maximum run length 11T set based on the run length restriction rule RLL (2, 10) in the CD standard, and the adjacent codewords C, C It has a function of adding a 3-bit combination bit 1b between them. This combination-bit addition circuit 22 includes (000), (001), (010), and (100) as candidates for the 3-bit combination bit 1b. ) Are prepared. Note that, although there are eight 3-bit combination bits 1b, in the sets (011), (101), (110), and (111) other than the four sets described above, two or more "1" s appear continuously. Alternatively, it cannot be used because “1” and “0” appear alternately and do not satisfy the run-length restriction rule RLL (2, 10).
[0039]
Then, in order to combine the codeword Cx and the codeword Cy sequentially input into the combination bit addition circuit 22, four sets of combination bits (000), (001), and (010) are provided between the codewords Cx and Cy. , (100) are temporarily added to generate a plurality of sets of codeword strings.
[0040]
At this time, as shown in FIG. 5, for example, one code word Cx is “010” from the 12th bit to the 14th bit, while the next code word Cy is “00100010000010”. The 13th bit of one codeword Cx is “1”, and the third bit of the next codeword Cy is “1”. Although the three sets of combination bits (000), (001), and (010) can strictly adhere to the run-length restriction rule RLL (2, 10), the fourth set of combination bits (100) has the run-length restriction rule RLL (2, 10). Since the condition (10) is not satisfied, the addition of the combined bit (100) is stopped.
[0041]
Then, after adding three sets of connection bits (000), (001), and (010) between the codewords Cx and Cy, the three sets of codeword strings {Cx (000) Cy} and {Cx (001) Cy are obtained. {Cx (010) Cy} is input to the DSV value calculation circuit 23 to calculate each DSV value of the three sets of codeword strings. As a result, as shown in Case 1 of FIG. When the combination bit (000) is added between Cy, the DSV value of the code word string {Cx (000) Cy} becomes +2, and as shown in case 2 shown in FIG. When the combination bit (001) is added to the code word string {Cx (001) Cy}, the DSV value becomes -4, and as shown in Case 3 shown in FIG. 5C, between the code words Cx and Cy. When the combination bit (010) is added, the code word sequence {Cx (010) Cy} SV value is -6.
[0042]
Thereafter, the three sets of code word strings from the DSV value calculation circuit 23 and the respective DSV values corresponding thereto are input to a DSV value comparison circuit / combination bit selection circuit 24, and the DSV value comparison circuit / combination bit selection circuit 24 And selecting one set of codeword strings {Cx (000) Cy} having a DSV value = + 2 such that the absolute value of the DSV is closest to zero among the DSV values of the three sets of codeword strings. This one set of code word strings {Cx (000) Cy} is output from the DSV value comparison circuit / combination bit selection circuit 24 as one determined code word string. In other words, the DSV value comparison circuit / combined bit selection circuit 24 selects the combined bit (000) corresponding to one decision code word string {Cx (000) Cy} whose DSV absolute value is closest to zero. become. Hereinafter, the above procedure is repeated following the next code word Cy to obtain one determined code word string {Cx (000) Cy...}.
[0043]
Thereafter, one decision code word string {Cx (000) Cy...} Whose DSV value is controlled is generated as a recording signal R (FIG. 1) suitable for recording, and the laser beam is used to produce a CD glass master. Alternatively, it is recorded on a CD-R.
[0044]
Then, a stamper disk (not shown) is manufactured based on the glass master disk for the CD, and a CD is manufactured using the stamper disk.
[0045]
From the above, the user plays back a CD containing music information to be copied in accordance with copy software stored in a hard disk (not shown) in a personal computer (not shown) in a CD drive (not shown), and outputs the CD from the CD drive. Also, music information desired to be recorded on the CD-R is input to a CD-R drive (not shown), and music information desired to be copied by the conventional modulation device 20 provided in the CD-R drive is obtained with permission of the copyright holder. It is possible to copy it directly to a CD-R without using it.
[0046]
Therefore, when the 16-bit music original data AD output from the CD drive is encoded by the conventional modulation device 20 provided in the CD-R drive, the music information recorded on the CD-R is recorded on the CD. Since the EFM signal format is exactly the same as that of the music information, the copied CD-R can be further copied, and the CD-R is circulated in large quantities in the world.
[0047]
Therefore, as described above, there is an example of an optical disc that can prevent copying of music information recorded on a CD or computer data recorded on a CD-ROM to a recordable / reproducible CD-R or CD-RW. (For example, see Patent Document 1).
[0048]
[Patent Document 1]
JP-A-2001-357536 (pages 4-5, FIG. 4)
[0049]
FIG. 6 is a longitudinal sectional view showing an optical disc on which a copy protection measure is taken as an example of a conventional example.
[0050]
The conventional optical disc 100 shown in FIG. 6 is disclosed in Patent Document 1 described above, and will be briefly described with reference to Patent Document 1 for an optical disc such as a CD-ROM and a DVD-ROM. In the conventional optical disc 100 in which a copy protection measure is taken, 3T to 14T (T is 0.133 μm) is usually based on a run-length restriction rule (described as a run-length suppression coding scheme in the same publication). ), A concave or convex portion having a continuous length even shorter than the minimum run length based on the run length restriction rule is recorded in the middle of this process. It is a feature.
[0051]
Specifically, as shown in FIG. 6, the pit A is formed in a convex shape with a length of 1T to 2T, and a pit B is formed in a concave shape with a length of 1T to 2T at a position X away from the pit A. The lengths of the pits A and B are values that are not based on the run length restriction rule.
[0052]
Therefore, in the conventional optical disc 100, among the run length restriction rules based on the minimum run length 3T and the maximum run length 14T, the minimum run length 3T is not strictly adhered to but is set to a smaller value 1T to 2T. Thus, the minimum pit length (or minimum land length) on the optical disc 100 is formed smaller than usual.
[0053]
[Problems to be solved by the invention]
Therefore, based on the above-described technical idea of the conventional optical disc 100, an uneven portion row (pit row) having a continuous length of 3T to 11T is formed based on the run length restriction rule RLL (2, 10) in the CD standard. In order to modify a part of the signal form of the CD by applying to the well-known CD, for example, in the encoding table shown in FIG. 2, the code word C for the input data word D = 255 is “00100000010010”. However, when it is desired to form a short uneven portion row (pit row) such as 1T, a modified CD can be manufactured by using a code word C such as “00100110010010” instead.
[0054]
When the thus modified CD is reproduced by a commercially available optical disk drive, the certification pit having a short continuous length of 1T to 2T in the data is shorter than the normal pit length (land length) of 3T to 11T. The RF signal read using the optical pickup does not reach a sufficient light level or a sufficient dark level, and the binarized signal obtained from the RF signal includes a 1T to 2T certification pit signal. Therefore, it cannot be determined whether or not the optical disc being reproduced is the original. Further, when music data recorded on a modified CD is reproduced by a commercially available optical disk drive, and the reproduced data is input to a CD-R drive and copied to a CD-R, the music data is copied without any problem. .
[0055]
Therefore, the copy prevention means based on the premise of the spread of a new player capable of detecting the proof pit like the optical disk 100 is used in a situation where a large number of players and CD-R drives are already on the market such as a CD. There is a problem that it cannot be applied.
[0056]
Further, similarly to the case of the optical disk, there is a problem that the digital information signal recorded on the digital magnetic tape is also copied.
[0057]
Therefore, when a code word string is generated without strictly observing a predetermined run-length restriction rule, the original recording medium on which the code word string is recorded can be reliably reproduced by a commercially available player, while the original recording medium A modulation device, a modulation method, and a recording medium that can prevent copying of a digital information signal recorded on a recording medium such as an optical disk or a digital magnetic tape by causing reproduction failure on a copy recording medium on which the data is copied are desired. It is rare.
[0058]
[Means for Solving the Problems]
The present invention has been made in view of the above problems, and a first invention is to convert an input data word of p bits into a code word of q bits, and to convert r bit combination bits between adjacent code words. In a modulation device that generates a codeword string by adding the codeword string and outputs the codeword string,
When generating the code word sequence, strictly adhere to the minimum run length (d + 1) T and the maximum run length (k + 1) T set for the code word sequence based on the run length restriction rule RLL (d, k). Instead, the DSV control is performed by adding the r combined bits between the adjacent codewords.
[0059]
According to a second aspect, in the modulation device according to the first aspect,
The adjacent code is allowed for the code word string without allowing the maximum run length (k + 1) T set based on the run length restriction rule RLL (d, k) to be allowed. A modulation device, characterized in that DSV control is performed by adding the r combination bits between words.
[0060]
According to a third aspect, in the modulation device according to the first or second aspect,
A code word string output in strict observance of the run-length restriction rule RLL (d, k) is input with specific data containing a specific frequency component as the input data word over a predetermined period, Further, the modulation device outputs the code word string without strictly observing the run-length restriction rule RLL (d, k) during the period.
[0061]
According to a fourth aspect of the present invention, in the modulation device according to the third aspect,
The modulation device is characterized in that the specific data is AC signal data or DC signal data that cannot be discriminated in terms of hearing.
[0062]
According to a fifth aspect of the present invention, in the modulation device according to the third aspect,
When the input data word is music information, and the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is inserted in a silent section formed between songs. A modulation device characterized in that:
[0063]
According to a sixth aspect, in the modulation device according to the third aspect,
When the input data word is music information, and when the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is included in a silent section formed between songs. In addition, the modulation device is inserted in a section excluding the section of index number 00.
[0064]
Further, the seventh invention converts a p-bit input data word into a q-bit code word, and adds a r-bit combination bit between adjacent code words to generate a code word sequence. In a modulation method for outputting a word string,
When generating the code word sequence, strictly adhere to the minimum run length (d + 1) T and the maximum run length (k + 1) T set for the code word sequence based on the run length restriction rule RLL (d, k). Instead, the DSV control is performed by adding the r combined bits between the adjacent codewords.
[0065]
According to an eighth invention, in the modulation method according to the seventh invention,
The adjacent code is allowed for the code word string by allowing the maximum run length (k + 1) T without strictly observing the maximum run length (k + 1) T set based on the run length restriction rule RLL (d, k). A modulation method characterized in that DSV control is performed by adding the r combination bits between words.
[0066]
According to a ninth aspect, in the modulation method according to the seventh or eighth aspect, the codeword string output while strictly observing the run-length restriction rule RLL (d, k) includes a component of a specific frequency. The specific data to be included is input as the input data word over a predetermined period, and during that period, the code word string is output without strictly observing the run-length restriction rule RLL (d, k). The modulation method is characterized in that:
[0067]
Further, a tenth invention provides the modulation method according to the ninth invention, wherein
The modulation method is characterized in that the specific data is AC signal data or DC signal data that cannot be discriminated in terms of hearing.
[0068]
An eleventh invention is directed to the modulation method according to the ninth invention, wherein
When the input data word is music information, and the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is inserted in a silent section formed between songs. The modulation method is characterized in that:
[0069]
A twelfth invention is directed to the modulation method according to the ninth invention, wherein
When the input data word is music information, and when the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is included in a silent section formed between songs. In addition, the modulation method is characterized by being inserted in a section excluding the section of index number 00.
[0070]
According to a thirteenth aspect, there is provided a recording medium that records the codeword string encoded by any one of the first to sixth modulation devices or any of the seventh to twelfth modulation methods.
[0071]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present embodiment of the modulation device, the modulation method, and the recording medium according to the present invention will be described in detail with reference to FIGS.
[0072]
In the modulation device, the modulation method, and the recording medium according to the present invention, for example, in the case of conforming to the CD standard, an input data word of p bits = 8 bits is converted into a code word C of q bits = 14 bits, and an adjacent data word is converted to a code word C of q bits = 14 bits. When the EFM signal 1 shown in FIG. 1B is generated by adding r bits = 3 combination bits 1b between the matching codewords C and C, the run-length restriction rule RLL (d, k) = RLL (2,10) The minimum run length (d + 1) T = 3T to the maximum run length (k + 1) T = 11T set based on RLL (2,10) is not strictly adhered to, but instead, the minimum run length (d + 1) An EFM signal 1 is generated by adding r combining bits 1b between adjacent codewords C and C to allow T = 3T to maximum run length (k + 2) T = 12T. Yes, and this When the original recording medium on which the FM signal 1 is recorded is reproduced, the first and second code word strings 1d and 1f composed of specific data described later can be reproduced without any trouble, while the original recording medium is copied. When the copied recording medium is reproduced, the reproduction signals of the first and second codeword strings 1d and 1f composed of the copied specific data have components of a specific frequency increased, so that reproduction is impossible. is there.
[0073]
By the way, in particular, the original recording medium on which the first and second codeword strings 1d and 1f composed of specific data are recorded includes pits (or lands) formed by the maximum run length 12T which does not satisfy the conventional CD standard. However, since the code word C itself is not affected, no data reading error occurs.
[0074]
In this embodiment described below, an optical disc such as a CD or a CD-ROM will be described as an example of a recording medium on which a digital information signal is recorded. The technical idea of this embodiment can be applied to a tape.
[0075]
<Example>
FIG. 7 is a block diagram schematically illustrating a modulation device and a modulation method according to the present embodiment according to the present invention.
FIGS. 8A and 8B are diagrams for explaining a case where the modulation apparatus of the present embodiment according to the present invention is used to perform encoding by allowing a maximum run length that does not satisfy the run length restriction rule in the CD standard. Figure,
FIG. 9 is a diagram showing a difference in a frequency spectrum caused by a change in the DSV value of a codeword string between the case of the original CD according to the embodiment of the present invention and the case of a CD-R obtained by copying the original CD.
[0076]
The modulation device 30 according to the present embodiment shown in FIG. 7 is applied to a glass master recording device (not shown) for producing a CD, and includes an 8-14 modulation circuit 31 and It is roughly composed of a combination bit addition circuit 32, a DSV value calculation circuit 33, and a DSV value comparison circuit / combination bit selection circuit.
[0077]
In the modulation device 30 of the present embodiment, the 16-bit music original data AD is divided into upper 8 bits and lower 8 bits, and each 8-bit input data word D is converted into each 14-bit code word C. For example, between one code word Cx, the following code word Cy, and the next next code word Cz,..., The run-length restriction rule RLL (d, k) = RLL in the CD standard The minimum run length (d + 1) T = 3T, which does not strictly adhere to the minimum run length (d + 1) T = 3T to the maximum run length (k + 1) T = 11T set based on (2, 10), is used instead. A plurality of sets of codeword strings are generated by temporarily adding the combination bits 1b of r bits = 3 so as to allow the maximum run length (k + 2) T = 12T. One whose absolute value of DSV is closest to zero Select the set of code word string, and outputs a set of the code word sequence of this one as finally determined one decision code word string.
[0078]
More specifically, in the modulation device 30 of the present embodiment, the 16-bit music original data AD is input to the 8-14 modulation circuit 31 in chronological order.
[0079]
In the 8-14 modulation circuit 31 described above, the input music original data AD is converted into the upper 8 bits of the input data word D and the lower 8 bits of the input data word D as described earlier with reference to FIG. The 8-bit input data word D is sequentially converted into a 14-bit code word C based on the encoding table shown in FIG. 2, for example, one code word Cx and the next code word Cy, the next codeword Cz, and so on are sequentially read.
[0080]
Then, one codeword Cx and codeword Cy are input from the 8-14 modulation circuit 31 to the combination bit addition circuit 32, and the codeword Cz has the best DSV value between the codeword Cx and codeword Cy. After adding a combination bit 1b to obtain a single decision code word string, it is input from the 8-14 modulation circuit 31 to the combination bit addition circuit 32.
[0081]
The combination bit addition circuit 32 is different from the combination bit addition circuit 22 in the conventional modulation device 20 described above with reference to FIG. 4 and is based on a run length restriction rule RLL (2, 10) according to the CD standard. A 3-bit combined bit between adjacent codewords C and C so as to allow the minimum run length 3T to the maximum run length 12T instead of strict adherence to the set minimum run length 3T to maximum run length 11T. 1b is provided, and four sets of (000), (001), (010), and (100) are prepared in the combination bit addition circuit 32 as candidates for three combination bits 1b. ing. Also in this embodiment, as in the conventional example, in the sets (011), (101), (110), and (111) other than the four sets described above, two or more "1" s appear continuously, or Since “1” and “0” appear alternately and do not satisfy the minimum run length 3T, they are deleted.
[0082]
At this time, the minimum run length 3T to the maximum run length 11T set based on the run length restriction rule RLL (d, k) = RLL (2, 10) in the CD standard as described above are not strictly adhered to. When the minimum run length 3T to the maximum run length 12T is allowed instead of the minimum run length of (d + 1) T = 3T, “0” is set between the logical values “1” and “1” in the code word C. When the number is at least d = 2, while the maximum run length is (k + 2) T = 12T, the number of “0” between the logical values “1” and “1” in the codeword C is At most, k + 1 = 11 are included.
[0083]
Then, in order to combine one codeword Cx input into the combination bit addition circuit 32 with the following codeword Cy, four sets of combination bits (000), (001) are interposed between the codewords Cx and Cy. ), (010), and (100) are temporarily added to generate a plurality of sets of codeword strings.
[0084]
At this time, if a maximum run length 12T that does not satisfy the maximum run length 11T according to the CD standard is allowed, the following characteristics are obtained. As shown in FIGS. 8A and 8B, for example, the code word Cx is a code word in which the 12th to 14th bits are “010”. The code word Cy is input, for example, as a code word “10000010000000” obtained by converting an 8-bit input data word “001” into 14 bits. The 13th bit of the code word Cx is “1”, whereas the first bit of the code word Cy is “1”. Are the minimum run length 3T to the maximum run length 12T, but the other three sets of the combination bits (001), (010), and (100) do not satisfy the minimum run length 3T. The addition of the connection bits (001), (010), and (100) is stopped.
[0085]
Then, after adding the first set of combination bits (000) between the code words Cx and Cy, the code word string {Cx (000) Cy} is input to the DSV value calculation circuit 33 to calculate the DSV value. 8 (a) and 8 (b), when the combination bit (000) is added between the code words Cx and Cy as in cases 11 and 12, the DSV value of the code word sequence {Cx (000) Cy} is +4, and the first set of codeword string {Cx (000) Cy} and the corresponding DSV value = + 4 are input to the DSV value comparison circuit / combined bit selection circuit 34.
[0086]
Thereafter, in the DSV value comparison circuit / combined bit selection circuit 34, only one set of input codeword strings is used. The code word string {Cx (000) Cy} is output as one finally determined code word string {Cx (000) Cy}.
[0087]
Next, after obtaining one decision code word sequence {Cx (000) Cy}, a DSV value is placed between the code word Cy and the code word Cz in this one decision code word sequence {Cx (000) Cy}. Is added from the 8-14 modulation circuit 31 to the combination bit addition circuit 32 in order to add the combination bit 1b that makes the best.
[0088]
Here, as shown in FIGS. 8A and 8B, the above-mentioned code word Cz is input as a code word “1000000000010010” obtained by converting an 8-bit input data word “249” into 14 bits, for example. .
[0089]
In the above-described combination bit addition circuit 32, four sets of combination bits (000), (001), and (4) are set between the code word Cy in one decision code word sequence {Cx (000) Cy} and the code word Cz. (010) and (100) are temporarily added to generate a plurality of sets of codeword strings.
[0090]
At this time, since the sixth bit of the code word Cy is “1” and the first bit of the code word Cz is “1”, two sets of the combination bits (000 ) And (100) satisfy the minimum run length 3T to the maximum run length 12T, but the other two sets of combination bits (001) and (010) do not satisfy the minimum run length 3T, so these combination bits (001) , (010) is stopped.
[0091]
Then, as in Case 11 shown in FIG. 8A, a connection bit (000) is added between the code word Cy in one decision code word sequence {Cx (000) Cy} and the code word Cz. In the code word sequence {Cx (000) Cy (000) Cz} obtained from the above, eleven consecutive “0” s from the seventh bit to the third bit of the combination bit (000) in the code word Cy Therefore, the maximum run length 12T is included.
[0092]
On the other hand, as in Case 12 shown in FIG. 8B, a connection bit (100) is added between the code word Cy in one decision code word sequence {Cx (000) Cy} and the code word Cz. In the code word sequence {Cx (000) Cy (100) Cz} obtained from the above, eight consecutive “0” s from the seventh bit to the first bit of the combination bit (100) in the code word Cy Therefore, the run length is 9T, which satisfies the maximum run length 12T, and also satisfies the maximum run length 11T according to the CD standard as in the conventional example.
[0093]
Thereafter, the two sets of codeword strings {Cx (000) Cy (000) Cz} and {Cx (000) Cy (100) Cz} obtained in the combination bit addition circuit 32 are input to the DSV value calculation circuit 33. Then, when the DSV value of each code word string is calculated, the DSV value of the code word string {Cx (000) Cy (000) Cz} becomes −1 as shown in a case 11 in FIG. 8B, the DSV value of the codeword string {Cx (000) Cy (100) Cz} is +9, and these two sets of codeword strings {Cx (000) Cy (000) ) Cz}, {Cx (000) Cy (100) Cz} and the respective DSV values corresponding to these two sets are input to the DSV value comparison circuit / combined bit selection circuit 34.
[0094]
Next, in the DSV value comparison circuit / combined bit selection circuit 34, two sets of code word strings {Cx (000) Cy (000) Cz} and {Cx (000) Cy (100) Cz} Among them, a set of code word strings {Cx (000) Cy (000) Cz} having a DSV value = −1 such that the absolute value of the DSV approaches zero is selected, and this code word string is finally converted. One determined code word string {Cx (000) Cy (000) Cz} is output as the determined code word string {Cx (000) Cy (000) Cz}, and thereafter, the above procedure is repeated following the code word Cz to obtain one determined code word string {Cx (000) Cy ( 000) Cz....
[0095]
By the way, in order to generate the maximum run length 12T in the combination of the code word C and the combination bit 1b, two code words C adjacent to each other with the combination bit 1b interposed therebetween, such as “Cy and Cz” in FIG. However, it is sufficient if the number of “0” including the combination bit 1b can be 11 consecutively when the combination bit 1b is added.
[0096]
The basic operation of the modulation device and the modulation method according to the present invention has been described with reference to specific examples. However, for the sake of simplicity of description, in calculating the DSV value, codeword strings {Cx (000) Cy}, {Cx (000) Cy (000) Cz}, and {Cx (000) Cy (000) ) Cz...｝, Such that the already calculated code word string is again subjected to the calculation. As a result, unless all the code words Cx, Cy, Cz... Are input, not only the DSV value cannot be calculated, but also the determined code word string can be output. For the determined DSV value of the code word string, a DSV value storage circuit (not shown) is provided in the DSV value calculation circuit 33 or the DSV value comparison circuit 34 to avoid duplication of the DSV value calculation and at least two code words. Is input, one decision code word string can be obtained.
[0097]
After that, the decision code word sequence {Cx (000) Cy (000) Cz...} In which the DSV value is best controlled is converted into a recording signal R (FIG. 1) suitable for recording, and the laser beam is used for CD. On a glass master (not shown). Then, a stamper disk (not shown) is manufactured based on the glass master disk for CD, and the present embodiment according to the present invention as shown in FIGS. An optical disk (CD) 10 serving as a recording medium of an example is manufactured.
[0098]
From the above, the modulation device 30 of the present invention capable of generating the maximum run length 12T in generating a codeword string by adding a 3-bit combination bit 1b having the best DSV value between adjacent codewords C and C is described. If used, the DSV value can take the smallest value in the code word string including the maximum run length 12T as in the case 11 shown in FIG. 8A.
[0099]
On the other hand, when the conventional modulation device 20 (FIG. 4) which does not allow the maximum run length 12T is used, the maximum run length 12T is allowed as in the case 12 shown in FIG. 8B. It is clear from the above that the DSV value becomes larger than the above. Here, the maximum run length 12T has been described as an example in which the run length restriction rule in the CD standard is not strictly adhered to. However, the present embodiment is also applicable to a long run length of 13T or more and a short run length of 2T or less. And the DSV value of the code word string can be made smaller than that in the case where the conventional modulation device 20 is used. However, as described in the related art section, it is not preferable to allow an extremely short run length or an extremely long run length from the viewpoint of transmission characteristics.
[0100]
By the way, when the maximum run length 12T is continuous for a certain period of the available code word string, and when the conventional modulation device 20 is used, the code word string as shown in FIG. Since the DSV value continuously increases, the DSV value may periodically fluctuate significantly during the continuous period. 8 (b) shows an example in which the DSV value rises to the right, that is, a positive increasing tendency. Even if the input code words Cx, Cy, Cz... If the polarity of the decision code word string corresponding to the word Cx is opposite, the DSV value will decrease to the right, that is, will tend to increase in the negative direction. As a result, when a signal recorded using the conventional modulation device 20 is reproduced, a component of a specific frequency is increased in a reproduced signal of a codeword string, and stable reproduction is impaired. On the other hand, when the modulation device 30 of this embodiment is applied, it is clear that stable reproduction is maintained. Hereinafter, input data corresponding to a specific codeword that causes such a difference is referred to as specific data.
[0101]
By applying this technical idea and recording a code word string generated from specific data while allowing a minimum run length of 3T to a maximum run length of 12T on an original recording medium, a copy recording medium on which the original recording medium is copied may be used. The reproduction data from the above-mentioned original recording medium is converted from the minimum run length 3T to the maximum run length 11T set by the conventional modulator 20 (FIG. 4) based on the run length restriction rule RLL (2, 10) in the CD standard. , A 3-bit combined bit 1b is added between adjacent codewords C and C to record a codeword string, so that a specific data portion allowing a maximum run length 12T on the original recording medium However, it is clear that the component of a specific frequency increases in the reproduced signal due to the large fluctuation of the DSV value in the copy recording medium. A.
[0102]
This is shown in FIG. As shown in FIG. 9, the reproduction frequency spectrum of the code word string of the specific data portion allowing the maximum run length 12T recorded on the original recording medium (CD) is gradually attenuated in the low frequency range. On the other hand, when the copy recording medium (CD-R) copied by the conventional modulation device 20 using the original recording medium (CD) is reproduced, the reproduction frequency spectrum of the code word string of the specific data part is specified in the low-frequency part. Frequency components have increased.
[0103]
When the technical idea of the present embodiment is applied to a CD-ROM containing computer data, it is only necessary to change the music original data AD shown in FIG. 7 to the computer original data. Description is omitted.
[0104]
Next, an optical disc serving as a recording medium of the present embodiment according to the present invention will be described with reference to FIG. FIGS. 10A and 10B are a perspective view and a longitudinal section for explaining an optical disc which is a recording medium of the present embodiment according to the present invention.
[0105]
As shown in FIGS. 10A and 10B, an optical disc (hereinafter, referred to as an original CD) 10 serving as a recording medium of the present embodiment according to the present invention includes a CD (Compact Disc) containing music information, It is applied to a read-only optical disc such as a CD-ROM (CD-Read Only Memory) containing computer data, and a digital information signal recorded on this original CD 10 is EFM (Eight to Fourteen Modulation: 8-14 modulation). According to the method, encoding is performed using the modulation device 30 of the present embodiment described above so that the minimum run length satisfies 3T and the maximum run length satisfies 12T with the highest priority.
[0106]
The above-mentioned original CD 10 is composed of a disc-shaped transparent disk substrate 11 having an outer diameter of 120 mm or 80 mm, a center hole diameter of 15 mm, and a substrate thickness of 1.2 mm. The pit sequence is converted into a digital pit sequence, and this pit sequence is carved as a spiral or concentric recording track 12 to record a signal surface.
[0107]
Here, the recording track 12 satisfies the minimum run length 3T to the maximum run length 12T among the code words Cx, Cy, Cz... Using the modulation device 30 of the present embodiment described above, and One decision code word string is generated by adding the three combination bits 1b having the best DSV value, and an uneven pit string is formed in advance over the entire surface corresponding to the one decision code word string. Is what it is. Further, a metal reflective film 14 and a protective film 15 are sequentially formed on the signal surface of the original CD 10, so that the original CD 10 is formed in a read-only type. The surface 11b of the transparent disk substrate 11 opposite to the one surface 11a is the side on which the reproduction laser beam Lp is irradiated.
[0108]
When the recording track 12 recorded on the original CD 10 is reproduced by a commercially available CD player or CD-ROM drive, the 14-bit codeword C itself satisfies the standard even if it includes the maximum run length 12T outside the CD standard. Therefore, no error occurs in the reproduced data. On the other hand, in the case where specific data that produces a large DSV value occurs for a certain period as an input data word D when the run length restriction rule in the CD standard as shown in FIG. In the manufactured optical disk, the DSV value of the code word string has a large amount of fluctuation, and fluctuates in a cycle based on one frame length or two frame lengths of the code word string. In this embodiment, the fluctuation of the DSV value of the code word string is improved by allowing the maximum run length 12T outside the CD standard, and stable reproduction can be obtained.
[0109]
Similarly, when the user copies the original CD 10 on which the music original data AD (FIG. 7) including the specific data described above is recorded to a copy recording medium (CD-R) using a CD-R drive (not shown). As described above, since the conventional modulation device 20 (FIG. 4) is provided in the CD-R drive, the original music data AD (FIG. 7) obtained by reproducing the original CD 10 is converted to the CD-R drive. When input to the drive, the minimum run length (d + 1) set in the conventional modulator 20 (FIG. 4) based on the run length restriction rule RLL (d, k) = RLL (2, 10) according to the CD standard. T = 3T to maximum run length (k + 1) T = 11T is strictly adhered to, and the code word string is generated by adding the 3-bit combination bit 1b. Modulation of Larger amount of change than with the location 30 (FIG. 7), which vary basis the period and one frame length or 2 frame length of the codeword sequence. Therefore, when this copy recording medium (CD-R) is reproduced by a commercially available CD player or CD-ROM drive, the reproduced signal has a specific effect that adversely affects the operation of the binarization circuit, tracking or focus servo, and the like. The frequency component increases, and the reproduction becomes unstable or cannot be reproduced. Thus, when the original CD 10 is copied onto a copy recording medium (CD-R), it is possible to prevent copyright infringement on the digital information signal. It is known that a large variation in the DSV value of the above-mentioned code word string adversely affects the stability of the reproducing apparatus, as described in the section of the prior art in JP-A-6-197024. Details are omitted here.
[0110]
Next, encoding and using specific data of an AC signal or a DC signal which cannot be discriminated in terms of audibility as the music original data AD is more effective for copy prevention measures, and this case will be described with reference to FIGS. 11 and 12. I do.
[0111]
FIG. 11A shows a case where the original CD of the present invention produced by encoding specific data of an AC signal which cannot be discriminated from the ear as music original data AD is reproduced, and FIG. 11B shows a case where the original CD of the present invention is copied. FIG. 12 (a) shows a case where a CD-R is reproduced, and FIG. 12 (a) shows a case where an original CD of the present invention produced by encoding specific data of a DC signal which cannot be perceived as audio original data AD is reproduced; (B) is a diagram showing a case where a CD-R obtained by copying the original CD of the present invention is reproduced.
[0112]
First, as shown in FIG. 11 (a), a signal which cannot be discriminated from the auditory sense as the music original data AD, for example, specific data composed of an AC signal of about 22.05 KHz is applied for a predetermined period to the present embodiment shown in FIG. The signal is input to an 8-14 modulation circuit 31 provided in the example modulation device 30. For example, when converting specific data consisting of an AC signal of about 22.05 KHz into a 14-bit codeword C, a minimum run length of 3T to a maximum run length of 12T is allowed without strictly observing the run length restriction rule, and A combination bit 1b is added to one code word Cx and the next code word Cy so that the DSV value becomes the best to generate one decision code word sequence. Is applied to an original CD 10 (FIG. 10) as a recording medium according to the first embodiment. When the original CD 10 is reproduced, the reproduced signal of the code word string does not increase the component of the specific frequency, so that it is reproduced as AC signal data which does not cause any trouble and cannot be discriminated in terms of audibility. So the user does not notice at all. It should be noted that, as shown in FIG. 11 (a), the specific data composed of the AC signal is subjected to fade-in and fade-out processing before and after a predetermined period as shown in FIG. Is also one of the features. Also, as the predetermined period in which the specific data of the AC signal is inserted, in the case of music data, a silent period between songs is suitable.
[0113]
On the other hand, as shown in FIG. 11B, when an original CD 10 on which specific data composed of an AC signal is recorded is copied to a CD-R and the CD-R is reproduced, the code word over the predetermined period is reproduced. Since a specific frequency component is increased in the reproduced signal of the column, an unreadable section occurs, and noise of a low frequency component is generated by data interpolation in the reproducing apparatus. The user can hear that the CD-R is an abnormal optical disk because the user can hear an unpleasant sound such as "sound" and prevent copyright infringement of the digital information signal on the copied CD-R. be able to.
[0114]
Next, FIG. 12A shows an example in which the AC signal data of FIG. 11A is replaced with specific data composed of a DC signal that cannot be discriminated from the ears as the music original data AD, and is produced by applying this. When the original CD 10 (FIG. 10) serving as the recording medium according to the present invention is reproduced, the reproduction signal of the code word string does not include any specific frequency component, so that there is no hindrance, and Since it is reproduced as DC signal data that cannot be distinguished above, the user does not notice at all. It is to be noted that, as shown in FIG. 12A, the specific data composed of a DC signal is subjected to fade-in and fade-out processing before and after a predetermined period, as shown in FIG. Is also one of the features. Also, as the predetermined period in which the specific data of the DC signal is inserted, in the case of music data, a silent period between songs is suitable.
[0115]
On the other hand, as shown in FIG. 12B, even when the original CD 10 on which the specific data including the DC signal is recorded is copied to the CD-R, an unreadable section occurs during the predetermined period as described above. I will. Therefore, even in this case, since the copied CD-R cannot be reproduced, copyright infringement of the digital information signal on the copied CD-R can be prevented.
[0116]
Here, when the input data word D to be p-q modulated is music information, and the p-bit input data word D is converted into a q-bit code word C, as described above, it is converted into one code word Cx. When a code word sequence is generated by reading at least the next code word Cy and the next next code word Cz at least in advance, the specific data of the AC signal or the DC signal that cannot be discriminated by the above-described audibility is included in the music information. The case of inserting a music piece into a silent section formed between music pieces will be described more specifically with reference to FIGS.
[0117]
FIG. 13 is a schematic diagram for explaining a silent section between music pieces on a general CD.
FIG. 14 is a schematic diagram for explaining a specific data insertion mode 1 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between songs in a recording medium according to the present invention;
FIG. 15 is a schematic diagram for explaining a specific data insertion mode 2 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between music pieces on the recording medium according to the present invention;
FIG. 16 is a schematic diagram for explaining a specific data insertion mode 3 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between music pieces on the recording medium according to the present invention;
FIG. 17 is a schematic diagram for explaining a specific data insertion mode 4 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between songs in the recording medium according to the present invention.
[0118]
Here, a case will be described in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section formed between songs on the original CD 10 (FIG. 10) serving as a recording medium according to the present invention and recorded. First, a silent section in the case of a general CD (Compact Disc) in which music information is recorded as reference data for this will be described first.
[0119]
That is, as shown in FIG. 13, in the case of a general CD containing music information, the TOC (not shown) in the lead-in area (not shown) formed on the inner peripheral side in accordance with the CD standard "Red Book". In the Table of Contents, the start address of each music piece is recorded in advance as the index information of the music information. Further, a plurality of songs recorded in the data area on the CD track also have a song number, an index number, an address and the like recorded for each song as shown.
[0120]
More specifically, when a plurality of songs recorded on a CD are generalized and displayed using n (where n is a natural number of 2 or more), for example, among the plurality of songs, for example, an (n−1) th song And the nth tune, a silent section is formed.
[0121]
Also, the song number n-1 corresponding to the (n-1) th song is the n-1th song from the performance end position (not shown) immediately after the performance of the (n-2) th song (not shown) has ended. The performance end position of the music number n-1 corresponding to the (n-1) -th song is recorded up to the performance end position immediately after the end of the performance, and the n-th song and the n-th song It is set in a silent section formed between them. Further, a music number n corresponding to the n-th music is recorded after the performance end position of the music number n-1 corresponding to the n-th music.
[0122]
Also, the index numbers for indicating the order of the movements in the respective songs can be assigned to the (n-1) th song and the nth song from 01 to 99 at the maximum. Are recorded from the position of the start address (not shown) of the (n-1) th music to the end of the performance of the music number n-1 of this music. The index number 01 (-99) in the tune is recorded from the position of the start address of the tune to the performance end position (not shown) of the tune number n of the tune. At this time, the start address (not shown) of the (n-1) th tune and the start address of the nth tune are located in a silent section between the tunes and located before the leading end at which the performance of each tune starts. It is recorded in.
[0123]
Further, in a silent section formed between the (n-1) th song and the nth song, there is a section in which an index number 00 that is not related to each song is recorded. Is set between the performance end position of the music number n-1 of the (n-1) th music and the position of the start address of the nth music.
[0124]
As described above, the (n-1) -th song ends at the performance end position of the song number n-1 of the song. On the other hand, the n-th song starts from the position of the start address of the song.
[0125]
Here, when a song number, an index number, and a start address are recorded for each song corresponding to a plurality of songs recorded in a data area on a track as in the above-described CD, the recording according to the present invention is performed. In the original CD 10 (FIG. 10) serving as a medium, for example, specific data of an AC signal or a DC signal, which cannot be discriminated by hearing, is shown in a silent section formed between the (n-1) th music and the nth music. 14 to 17 are inserted and recorded based on any of the specific data insertion modes 1 to 4 shown in FIG.
[0126]
First, as shown in FIG. 14, in the case of the specific data insertion mode 1 in the recording medium according to the present invention, for example, between the (n−1) th song and the nth song on the original CD 10 (FIG. 10). The specific data described above is inserted and recorded in the silent section formed in the section No. 1 and in the section of index number 00 assigned to the position as described above.
[0127]
As a result, when the original CD 10 in which the specific data is inserted and recorded in the section of index number 00 is entirely copied onto a CD-R (copy recording medium), the copied CD-R also has the (n-1) th tune. When the copied CD-R is played back, the specific data is recorded in the silent section formed between the song and the n-th song, and the specific data is recorded in the section with index number 00. In the same manner as described above, an unreadable section occurs due to the copied specific data and the CD-R becomes unreproducible, so that copyright infringement of the digital information signal on the copied CD-R can be prevented beforehand. .
[0128]
However, when copying the original CD10 recorded by inserting the specific data into the section of index number 00 to a CD-R, the user avoids the silent section between the songs by random access to the original CD10. It is also conceivable to copy a plurality of songs from the start address position to the CD-R. In this case, since the silent section between the songs is not copied on the CD-R, the The specific data recorded in the section of each index number 00 set in the... Are not copied, so that even if the copied CD-R is reproduced, the unreadable section does not occur, and the specification on the original CD 10 is not performed. The data copy protection function will not work on the copied CD-R. In order to avoid this, according to the present invention, even when the user collects a plurality of songs from the position of the start address of each song on the original CD 10 and copies them to a CD-R, each recorded in the silent section between the songs. By adopting any of the specific data insertion modes 2 to 4 shown in FIGS. 15 to 17 described below so that the specific data is always copied, the copy protection function in the original CD 10 can be further improved. Things.
[0129]
That is, as shown in FIG. 15, in the case of the specific data insertion mode 2 in the recording medium according to the present invention, for example, on the original CD 10, it is formed between the (n-1) th music and the nth music. The performance end position of the music number n-1 of the (n-1) th music set in the silent section is set to the start address of the nth music from the performance end position of the music number n-1 in the case shown in FIG. The specific data described above is inserted and recorded between the end of the (n-1) th tune and the performance end position of the tune number n-1 extended here. Accordingly, the section in which the index number 00 is recorded is shortened.
[0130]
Although illustration is omitted here, the performance end position of the music number n-1 of the (n-1) th music is extended until it coincides with the position of the start address of the nth music, and the (n-1) th music is played. Specific data may be inserted and recorded between the end of the music and the performance end position of the music number n-1 extended to the position of the start address. In this case, the index number 00 is recorded. Although the section is deleted, the (n-1) th song ends at the performance end position of the song number n-1, and the nth song starts from the start address position of the nth song which is the same position as this position. It does not cause any trouble.
[0131]
Therefore, when the original CD 10 is manufactured by adopting the technical idea of the specific data insertion mode 2 as shown in FIG. 15, the specific data that cannot be discriminated in terms of audibility is in a silent section formed between music pieces. In addition, the original CD 10 is inserted and recorded in a section other than the section of the index number 00, and the user copies a plurality of songs from the start address of each song to the CD-R with respect to the original CD10. Even in this case, for example, since the (n-1) th song is always copied to the performance end position of the song number n-1, the end of the (n-1) th song on the original CD 10 and the song number n- Since the specific data recorded between the end of the performance 1 is always copied onto the CD-R, if the copied CD-R is reproduced, the CD-R cannot be reproduced due to the specific data. It is as described above. Of course, even if the original CD 10 employing the technical idea of the specific data insertion mode 2 as shown in FIG. 15 is entirely copied to the CD-R, the specific data is copied following the end of the (n-1) th music. It is obvious.
[0132]
Next, as shown in FIG. 16, in the case of the specific data insertion mode 3 in the recording medium according to the present invention, for example, the original CD 10 is formed between the (n-1) th music and the nth music. The position of the start address of the n-th song set in the silence section is set to the performance of the song number n-1 of the (n-1) -th song from the start address position of the n-th song in the case shown in FIG. After moving to the end position side, the above-described specific data is inserted and recorded between the position of the start address of the n-th song and the leading end of the song. Accordingly, the section in which the index number 00 is recorded is shortened. Further, in this case, the position of the start address of the n-th song is moved to the (n-1) -th song side, so that the position from the start address of the n-th song to the head of the n-th song is shifted. Although the silent state tends to last a little longer, the section from the start address of the nth song to the beginning of the nth song is set within the time range in which the user can accept the silent state. It will not cause any trouble.
[0133]
Although not shown here, the start address of the n-th song is matched with the performance end position of the song number n-1 of the n-1th song, and the performance of the song number n-1 is ended. Specific data may be inserted and recorded between the start address position of the n-th song matched with the position and the leading end of the n-th song. In this case as well, a section in which index number 00 is recorded Is deleted, but the (n-1) -th song ends at the performance end position of the song number n-1, and the n-th song starts from the position of the start address of the n-th song which is the same position as this position. So there is no trouble.
[0134]
Therefore, when the original CD 10 is manufactured by adopting the technical idea of the specific data insertion mode 3 as shown in FIG. 16, the specific data that cannot be discriminated in terms of audibility is in a silent section formed between music pieces. In addition, the original CD 10 is inserted and recorded in a section other than the section of the index number 00, and the user copies a plurality of songs from the start address of each song to the CD-R with respect to the original CD10. Even in this case, for example, since the data is always copied from the position of the start address of the n-th song, the specific data recorded between the start address of the n-th song and the leading end of the song on the original CD 10 is also a CD. As described above, if the copied CD-R is reproduced, the CD-R cannot be reproduced due to the specific data if the copied CD-R is reproduced. Of course, even if the original CD 10 employing the technical idea of the specific data insertion mode 3 as shown in FIG. 16 is entirely copied to the CD-R, the specific data is copied following the start address of the n-th music. Is obvious.
[0135]
Next, as shown in FIG. 17, in the case of the specific data insertion mode 4 in the recording medium according to the present invention, the specific data insertion mode 1 shown in FIG. 14, the specific data insertion mode 2 shown in FIG. The original CD 10 is produced by combining with the specific data insertion mode 3 shown in FIG. 16, for example, between the end of the (n-1) th song and the performance end position of the song number n-1 of this song. The above-mentioned specific data is inserted and recorded, and the specific data is also inserted and recorded in the section of index number 00, and further, between the position of the start address of the n-th song and the leading end of the song. The specific data is inserted and recorded.
[0136]
Although FIG. 17 shows a case where three sets of the specific data insertion modes 1 to 3 described above are combined, the present invention is not limited thereto, and at least two sets of the specific data insertion modes 1 to 3 are combined. Alternatively, an original CD 10 may be manufactured.
[0137]
Therefore, the original CD 10 produced by combining at least two or more of the above-mentioned specific data insertion modes 1 to 3 can be entirely copied to a CD-R, or the user can record a plurality of songs from the start address of each song. Even if the data is copied onto a CD-R, at least one or more specific data is always copied between the songs on the CD-R. Therefore, when the copied CD-R is reproduced, at least one or more specific data is reproduced. As described above, the CD-R falls into an unreproducible state.
[0138]
In the modulation device, the modulation method, and the recording medium according to the present invention described in detail above, the case of the EFM modulation (8-14 modulation) system used for the CD has been described. The input data word D of bits is converted into the code word C of q bits, and the minimum run length (d + 1) T to the maximum run length (D) set based on the run length restriction rule RLL (d, k) on the optical disk. k + 1) T, without strict adherence to the minimum run length (d + 1) T to the maximum run length (k + 2) T. The technical idea described above can be applied to any pq modulation that generates a codeword string by adding the combination bit 1b.
[0139]
Furthermore, when the input data word D to be p-q modulated is music information and the p-bit input data word D is converted into a q-bit code word C, the run-length restriction rule RLL (d , K), the minimum run length (d + 1) T to the maximum run length (k + 2) T are used instead of the minimum run length (d + 1) T to the maximum run length (k + 1) T. A codeword string is generated by adding r-bit combination bits 1b having the best DSV value between adjacent codewords C and C so as to be allowed, and the pq modulated music information is converted to the original CD10 (FIG. 10). ) May be recorded by inserting specific data of an AC signal or a DC signal, which cannot be discriminated in terms of audibility, into a silent section formed between music pieces in music information, and furthermore, a copy protection function. The performance of Ri In order to increase even more, be in a silent section formed between tracks specific data as described above, and, in which may be recorded by being inserted into a section except the section index number 00.
[0140]
【The invention's effect】
According to the modulation device, the modulation method, and the recording medium of the present invention described in detail above, a p-bit input data word is converted into a q-bit code word, and an r-bit combination bit is inserted between adjacent code words. When the codeword string is generated by adding the minimum runlength (d + 1) T and the maximum runlength (k + 1) T set for the codeword string based on the run length restriction rule RLL (d, k). DSV control is performed by adding r combining bits between adjacent codewords without strict adherence. At this time, the codeword string is set based on the run-length restriction rule RLL (d, k). Since the maximum run-length (k + 1) T is not strictly adhered to and the maximum run-length (k + 2) T is allowed to add r coupled bits between adjacent codewords to generate a codeword string, Recording medium on which codeword strings are recorded In this case, normal reproduction can be performed without any trouble, and when a copy recording medium on which this recording medium is copied is reproduced, a reproduced signal of the copied code word string has a specific frequency component increased and the DSV value is also reduced. Since the digital information signal on the copied copy recording medium can be prevented from being infringed, it is possible to prevent the reproduction of the digital information signal on the copied recording medium.
[0141]
According to the modulation device of the present invention or the modulation method of the present invention, an AC signal or a DC signal data which cannot be perceived as an input data word is input for a predetermined period, and this input data word is encoded by pq modulation. If the recorded recording medium is copied and reproduced on a recording medium, when the copied recording medium is reproduced, an unpleasant sound such as a "geek sound" or a "gear sound" is generated during an unreadable section due to DSV control failure. In addition, it is possible to notify the user that the copy recording medium is an abnormal recording medium, and to prevent copyright infringement on the digital information signal on the copied recording medium.
[0142]
Further, according to the modulation device, the modulation method, and the recording medium of the present invention, when the input data word is music information and specific data of an AC signal or a DC signal that cannot be discriminated from perception is input over a predetermined period. The specific data may be inserted into a silent section formed between songs and / or the specific data may be inserted into a silent section formed between songs and an index By inserting the data into a section excluding the section of the number 00 and recording it on the recording medium, when the copy recording medium obtained by copying this recording medium is reproduced, an unreadable section occurs due to the copied specific data and the copy recording medium is generated. Therefore, it is possible to prevent copyright infringement on the digital information signal on the copy recording medium.
[Brief description of the drawings]
1A and 1B are diagrams for explaining a signal format of music information recorded on a CD, wherein FIG. 1A shows music original data, and FIG. 1B shows an EFM signal.
FIG. 2 is a diagram showing an encoding table at the time of 8-14 modulation.
FIGS. 3A and 3B are diagrams for explaining DSV control during 8-14 modulation.
FIG. 4 is a block diagram schematically illustrating a conventional modulation device.
FIGS. 5 (a) to 5 (c) show a code obtained by adding a combination bit between one codeword and a codeword following the codeword while strictly observing a predetermined run-length restriction rule using a conventional modulator. FIG. 10 is a diagram for explaining a state in which DSV values of a plurality of sets of code word strings are calculated when (000), (001), and (010) are temporarily added as connection bits when a word string is generated.
FIG. 6 is a longitudinal sectional view showing an optical disk on which a copy protection measure is taken as an example of a conventional example.
FIG. 7 is a block diagram schematically illustrating a modulation device and a modulation method of the present embodiment according to the present invention.
FIGS. 8A and 8B illustrate a case where the modulation apparatus according to the embodiment of the present invention is used to perform encoding by allowing a maximum run length that does not satisfy a run length restriction rule according to the CD standard. FIG.
FIG. 9 is a diagram showing a difference in a frequency spectrum caused by a change in a DSV value of a codeword string between an original CD according to the embodiment of the present invention and a CD-R obtained by copying the original CD. .
FIGS. 10A and 10B are a perspective view and a longitudinal section for explaining an optical disc serving as a recording medium according to the present embodiment according to the present invention.
FIG. 11A shows a case where an original CD of the present invention produced by encoding specific data of an AC signal which cannot be discriminated from the ear as music original data AD is reproduced, and FIG. 11B shows a case where the original CD of the present invention is reproduced. FIG. 11 is a diagram showing a case where a copied CD-R is reproduced.
FIG. 12 (a) shows a case where an original CD of the present invention produced by encoding specific data of a DC signal which cannot be discriminated from the ear as music original data AD is reproduced, and FIG. 12 (b) shows a case where the original CD of the present invention is reproduced. FIG. 11 is a diagram showing a case where a copied CD-R is reproduced.
FIG. 13 is a schematic diagram for explaining a silent section between music pieces on a general CD.
FIG. 14 is a schematic diagram for explaining a specific data insertion mode 1 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between music pieces in the recording medium according to the present invention.
FIG. 15 is a schematic diagram for explaining a specific data insertion mode 2 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between music pieces in the recording medium according to the present invention.
FIG. 16 is a schematic diagram for explaining a specific data insertion mode 3 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between music pieces in the recording medium according to the present invention.
FIG. 17 is a schematic diagram for explaining a specific data insertion mode 4 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between songs in the recording medium according to the present invention.
[Explanation of symbols]
1 ... EFM signal,
1a: synchronization signal, 1b: combination bit, 1c: subcode,
1d: first code word sequence, 1e: C2 error correction code,
1f: second code word string, 1g: C1 error correction code,
10 ... an optical disc serving as a recording medium of the present embodiment according to the present invention;
11: transparent disk substrate, 12: recording track,
20: a conventional modulation device,
21 ... 8-14 modulation circuit, 22 ... combined bit addition circuit,
23 ... DSV value calculation circuit, 24 ... DSV value comparison circuit / coupled bit selection circuit,
30... The modulation device of the present embodiment,
31 ... 8-14 modulation circuit,
32 ... combined bit addition circuit, 33 ... DSV value calculation circuit,
34 ... DSV value comparison circuit / combination bit selection circuit

Claims (13)

A modulation device that converts a p-bit input data word into a q-bit code word, adds a r-bit combination bit between adjacent code words, generates a code word sequence, and outputs this code word sequence ,
When generating the code word sequence, strictly adhere to the minimum run length (d + 1) T and the maximum run length (k + 1) T set for the code word sequence based on the run length restriction rule RLL (d, k). A modulation device, wherein DSV control is performed by adding the r combined bits between adjacent codewords. The modulation device according to claim 1,
The adjacent code is allowed for the code word string without allowing the maximum run length (k + 1) T set based on the run length restriction rule RLL (d, k) to be allowed. A modulation device, wherein the r-bit combination bits are added between words to perform DSV control. In the modulation device according to claim 1 or 2,
A code word string output in strict observance of the run-length restriction rule RLL (d, k) is input with specific data containing a component of a specific frequency as the input data word over a predetermined period, In addition, during the period, the modulation apparatus outputs the codeword string without strictly observing the run-length restriction rule RLL (d, k). The modulation device according to claim 3,
The modulation device according to claim 1, wherein the specific data is AC signal data or DC signal data that cannot be discriminated by hearing. The modulation device according to claim 3,
When the input data word is music information, and when the specific data which cannot be distinguished in terms of audibility is input for a predetermined period, the specific data is inserted into a silent section formed between songs. A modulation device characterized by the above-mentioned. The modulation device according to claim 3,
When the input data word is music information, and when the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is included in a silent section formed between songs. And a modulator inserted in a section excluding the section of index number 00. A modulation method for converting a p-bit input data word into a q-bit code word, adding a r-bit combination bit between adjacent code words to generate a code word sequence, and outputting the code word sequence. ,
When generating the code word sequence, strictly adhere to the minimum run length (d + 1) T and the maximum run length (k + 1) T set for the code word sequence based on the run length restriction rule RLL (d, k). A modulation method characterized by adding the r combination bits between adjacent codewords to perform DSV control. The modulation method according to claim 7,
The adjacent code is allowed for the code word string without allowing the maximum run length (k + 1) T set based on the run length restriction rule RLL (d, k) to be allowed. A modulation method, wherein the r bits are added between words to perform DSV control. In the modulation method according to claim 7 or claim 8,
A code word string output in strict observance of the run-length restriction rule RLL (d, k) is input with specific data that includes a component of a specific frequency as the input data word over a predetermined period, In addition, during the period, the codeword string is output without strictly observing the run-length restriction rule RLL (d, k). The modulation method according to claim 9,
The modulation method according to claim 1, wherein the specific data is AC signal data or DC signal data that cannot be discriminated in terms of hearing. The modulation method according to claim 9,
When the input data word is music information, and the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is inserted into a silent section formed between songs. A modulation method, comprising: The modulation method according to claim 9,
When the input data word is music information, and the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is included in a silent section formed between songs. A modulation method characterized by being inserted in a section excluding the section of index number 00. 13. A recording medium on which the code word string encoded by any one of the modulation device according to claim 1 and the modulation method according to claim 7 is recorded.

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