JP2006024321A - Device and method for modulation, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent copying of a digital information signal in an original CD. <P>SOLUTION: When the input data word of p bits is converted into a code word of q bits, the connection bit of r bits is added between adjacent code words to generate a code word string, and the code word string is recorded in a recording medium such as an optical disk, especially copy preventing effect is added by using TOC information recorded in the lead-in area of an original CD 10. When an input data word is music information, the music information and inaudible specific data are added together to code them. When a decided code word string having a small DCV value is obtained to be recorded in the original CD 10, the specific data is inserted into the music section of the music information or a silence interval formed between pieces of music. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  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.

  With the advent of the digital multimedia era, large-capacity digital information signals are recorded on recording media such as optical disks.

  For example, optical discs such as CDs (Compact Discs) that record music information and CD-ROMs (CD-Read Only Memory) that contain computer data are digital information signals on a disc-shaped transparent disc substrate and concave pits. It is converted into a pit row with a convex land, and this pit row is engraved on a transparent disk substrate as a spiral or concentric track, and it is formed in a read-only type, and the desired track is accessed at high speed during playback It is widely used because it is suitable for mass production and can be obtained at low cost.

  By the way, although the music information recorded on the CD and the computer data recorded on the CD-ROM are protected by the copyright law, there is no signal deterioration because they are digital information. The user can write onto a write-once optical disc such as a CD-R (Compact Disc-Recordable) that can be written only once without obtaining the permission of the copyright holder, or a CD-RW (Compact Disc-ReWriteable) that can be written multiple times. It is possible to copy.

  The above-described write-once optical discs such as CD-R and CD-RW have substantially the same appearance as read-only optical discs such as CD and CD-ROM, but a concave groove is spirally formed on a transparent disc substrate. Alternatively, it is formed concentrically, spin coated with an organic dye serving as a recording layer on the concave groove side, and further, a reflective film and a protective film are sequentially formed on the organic dye, Moreover, it is available at a low cost.

  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 that of the CD or CD-ROM. Therefore, the copyright is infringed.

  In the present invention, particularly, the case where music information is recorded on a recording medium is targeted. Therefore, a code word string of music information recorded on a CD will be described below.

FIG. 1 is a diagram for explaining a signal format of music information recorded on a CD, where (a) shows music source data and (b) shows an EFM signal.
FIG. 2 is a diagram showing an encoding table at the time of 8-14 modulation.
3 (a) and 3 (b) are diagrams for explaining DSV control during 8-14 modulation.
FIG. 4 is a diagram for explaining the subcode in the EFM signal shown in FIG. 1B, (a) shows the subcode data before modulation, and (b) shows the Q channel in the subcode data. Figure showing the frame structure,
FIG. 5 is a diagram showing a state in which one block is composed of 98 EFM signals shown in FIG.

  First, the music information is recorded on the CD in a signal format conforming to the CD standard “Red Book” or the IEC (International Electrotechnical Commission) 908 standard.

  At this time, generally, the pit length recorded on the CD is limited to the minimum run length (minimum pit length or minimum land length) due to optical transmission characteristics of recording / reproduction and physical restrictions 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 has a low frequency component and DC component suppression characteristics. It needs to be modulated.

  Among modulation schemes that satisfy this limitation, the EFM (Eight to Four Modulation: 8-14 modulation) scheme used for CDs has a minimum run length of 3T (T = period of channel bits) and a maximum run length of 11T. It is what.

  That is, as shown in FIG. 1A, the music source data AD recorded on the CD is digital data, and the upper 8 bits (1 byte) + the lower 8 bits (1 byte) = 16 bits (2 bytes). A unit is constituted, and the music source data AD is constituted by a plurality of one unit.

  When the original music data AD shown in FIG. 1A is recorded on the glass master disk by laser beam at the time of mastering, the original music data AD is converted into an EFM signal format so that the signal form is suitable for recording. Then, it is recorded on the glass master disk in the form of EFM signal 1 shown in FIG. 1 (b), and thereafter, a metal master disk, a mother disk, and a stamper disk are sequentially manufactured based on the glass master disk by electroforming. Thereafter, the stamper disk is mounted in the injection molding machine, and the signal surface of the stamper disk 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.

  Here, in the format of the EFM signal 1 described above, the input music source 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 a p-bit = 8-bit input data word D, a q-bit = 14-bit run-length limited code (hereinafter referred to as “q-bit = 14-bit”) satisfying a predetermined run-length restriction rule with a minimum run length of 3T and a maximum run length of 11T. 1), and, as shown in FIG. 1B, between the converted codeword C and the codeword C, for holding a run length restriction rule and DSV (Digital Sum Value) EFM signal 1 is generated by adding a combination bit 1b of r bits = 3 bits for control and forming first and second codeword strings 1d and 1f described later. is doing.

  At this time, when a predetermined run length restriction rule is satisfied, if the minimum run length is 3T, the number of “0” s between the logical values “1” and “1” in the codeword C is the smallest and d = 2 On the other hand, when the maximum run length is 11T, the maximum number of “0” is included between the logical values “1” and “1” in the codeword C = k = 10. In other words, when the run length restriction rule RLL (d, k) = RLL (2,10) is satisfied, the minimum run length is based on the run length restriction rule RLL (d, k) = RLL (2,10). (D + 1) T = 3T is set, and the maximum run length is set as (k + 1) T = 11T. The first and second codeword strings 1d and 1f, which are combined by adding a 3-bit combined 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 is satisfied, and when the NRZI conversion is performed on the first and second codeword sequences 1d and 1f as described later, the minimum run length 3T has the minimum inversion interval, while the maximum The run length 11T represents the maximum inversion interval.

  Then, the EFM signal 1 subjected to pq modulation = 8-14 modulation 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 direct current component and the low frequency component of the EFM signal 1 can be reduced.

  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, and the NRZI conversion has a polarity in the bit “1” as is well known. Inverted and modulated without inverting the polarity at bit “0”, the waveform after NRZI conversion becomes the recording signal R to the glass master, and the L (low) level section in this recording signal R For example, a pit row is formed by corresponding to a concave pit (or convex land) and an H (high) level section in the recording signal R corresponding to, for example, a convex land (or concave pit).

  Further, as shown in FIGS. 3A and 3B, the above-described DSV has an H (high) level waveform after NRZI conversion from the start time of the code word string in the EFM signal 1 to the present time. It is an integral value that is sometimes integrated as “1” (positive polarity) and as “−1” (negative polarity) at the L (low) level. At this time, in the NRZI conversion, polarity inversion is performed with the data bit “1”. Therefore, even if the code word has the same bit pattern, it differs depending on the waveform state after the NRZI conversion just before the code word is connected. As shown in FIG. 3A, when the previous waveform state is L (low) level with respect to the input data word = 002, and immediately before the input data word = 002 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 combined via a combination bit, FIG. The absolute values of both DSVs according to FIG.

  Here, as a combined bit of 3 bits between adjacent codewords C and C so that the absolute value of DSV approaches substantially zero while satisfying the run length restriction rule RLL (d, k) = RLL (2,10), By selecting and adding any one of the groups (000), (001), (010), and (100), the direct current component of the waveform of the recording signal R is reduced, and as a result, the recording signal When the waveform of R is viewed over a long period, the H (high) level section and the L (low) level section appear at approximately the same rate, so that the concave pit section and the convex land section also appear at approximately the same ratio. Thus, the DSV value is controlled.

  Returning to FIG. 1 (b), one frame of the EFM signal 1 described above includes a frame synchronization signal 1a, a combined bit 1b, a subcode 1c, a combined bit 1b, a first codeword string 1d, a combined bit 1b, and a C2 error from the top. The correction code 1e, the combined bit 1b, the second codeword string 1f, the combined bit 1b, the C1 error correction code 1g, and the combined bit 1b are arranged in this order, and are composed of 588 channel bits in total for one frame. .

  Here, the frame synchronization signal 1a arranged at the head can be identified with respect to each of the signals 1b to 1g as signals of 11T, 11T, and 2T in order to indicate the head of the frame using 24 bits. .

  Further, the subcode 1c arranged via the three-bit combination bit 1b after the frame synchronization signal 1a is a signal for performing reproduction control to the CD. As shown in FIG. 4 (a), the pre-modulation subcode data SD corresponding to the subcode 1c is completed with 98 frames consisting of 8 bits b1 to b8, and common to each channel in the first two frames. Subcode synchronization signals 1 and 2 are assigned, and the remaining 96 frames are assigned 8 channels of P, Q, and R to W. At this time, the P channel is a simple reproduction control, that is, a cue signal for each song. The Q channel indicates the content type of control 4 bits for indicating audio data, computer data, etc. and subsequent data 72 bits, as shown in FIG. 4B, in order to perform finer reproduction control. 4 bits for the address, 72 bits of data indicating the recording start time, and 16 bits of CRC (Cyclic Redundancy Code) for detecting the error of the cyclic code are composed of 96 bits in total. Furthermore, the 6 channel bits of R to W are used for special purposes such as still image and karaoke character display.

  Returning to FIG. 1 (b) again, the first code word string 1d arranged via the sub-code 1c and the 3-bit combined bit 1b has p = 8 bits of each input data word D (each music source data). 12 by converting each codeword C to q = 14 bits with reference to the encoding table shown in FIG. 2 and adding a combined bit 1b of 3 bits between adjacent codewords C and C. Code word C (12 symbols) and 11 combined bits 1b.

  In addition, the C2 error correction code 1e arranged after the first codeword string 1d via the three combined bits 1b is converted into the first codeword string 1d and the second codeword string 1f of the EFM signal 1 during CD reproduction. In contrast, error correction is performed.

  Further, the second codeword string 1f arranged via the 3 combined bits 1b after the C2 error correction code 1e is composed of 12 codewords C (12 symbols) as in the first codeword string 1d. It consists of 11 combined bits 1b.

  Further, the C1 error correction code 1g arranged after the second codeword string 1f via the combined bit 1b of 3 bits is 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.

  Then, 98 blocks (= 98 frames) of recording signals after NRZI conversion are performed on one frame of the EFM signal 1 as described above to constitute one block. The block corresponds to a period of 1/75 seconds.

  Here, a conventional modulation device will be described with reference to FIGS.

FIG. 6 is a block diagram schematically showing a conventional modulation device,
7 (a) to 7 (c) show codes obtained by adding a coupling bit between one codeword and the next codeword following the same while strictly complying with a predetermined run length restriction rule using a conventional modulation device. When a word string is generated, when (000), (001), (010), and (100) are temporarily added as combined bits, a state in which DSV values of a plurality of sets of code word strings are calculated is described. FIG.

  The conventional modulation device 20 shown in FIG. 6 includes a glass master recording machine (not shown) for producing a CD, and a CD-R drive (for copying music information recorded on the CD to the CD-R). (Not shown), the frame synchronization signal generator 21, the subcode encoder 22, the CIRC encoder 23, the 8-14 modulation circuit 24, the combined bit addition circuit 25, and the DSV value. An arithmetic circuit 26 and a DSV value comparison circuit / combined bit selection circuit 27 are roughly configured.

  More specifically, the conventional modulation device 20 is separately provided with a frame synchronization signal generator 21 for generating the 22-bit frame synchronization signal 1a described with reference to FIG. The frame synchronization signal 1a generated by the frame synchronization signal generator 21 is added to the head of the EFM signal 1 (FIG. 1).

  In addition, the subcode data SD before modulation corresponding to the subcode 1c described with reference to FIG. 1B is converted into the predetermined format shown in FIGS. 4A and 4B by the subcode encoder 22. 8 bits are generated and input to the 8-14 modulation circuit 24.

  Further, the 16-bit music source data AD is separated into the upper 8 bits of the input data word D and the lower 8 bits of the input data word D as described above with reference to FIG. 1A, and the CIRC (Cross Interleaved Reed). -Solomon Code) is input to the encoder 23 in chronological order, where error correction code processing is performed by combining two Reed-Solomon codes, and each 8-bit input data word D including the error correction code is subjected to 8-14 modulation. It is sent to the circuit 24.

  Next, in the 8-14 modulation circuit 24, the input 8-bit subcode data SD is converted into a 14-bit subcode 1c based on the encoding table shown in FIG. 2, and the subcode 1c is converted. Is added after the frame synchronization signal 1a of the EFM signal 1 (FIG. 1).

  Further, in the 8-14 modulation circuit 24, when the 8-bit input data word D is sequentially converted into the 14-bit code word C based on the encoding table shown in FIG. The next code word Cy following the one code word Cx is sequentially read. Then, one code word Cx and the next code word Cy are input from the 8-14 modulation circuit 24 to the combined bit adding circuit 25.

  Next, the combined bit adding circuit 25 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 code words C, C The combination bit adding circuit 25 is provided with a function of adding three combined bits 1b between them, and (000), (001), (010), (100) are candidates for the three combined bits 1b in the combined bit adding circuit 25. 4 sets are prepared. Although there are 8 combinations of 3 bits 1b, two or more “1” s appear continuously in the groups (011), (101), (110), and (111) other than the above four groups, Alternatively, since “1” and “0” appear alternately, the run length restriction rule RLL (2, 10) is not satisfied, and therefore, it cannot be used.

  Then, in order to combine the code word Cx and the code word Cy sequentially input into the combined bit adding circuit 25, four sets of combined bits (000), (001), (010) between the code words Cx and Cy. , (100) are temporarily added to generate a plurality of sets of codeword strings.

  At this time, as shown in FIG. 7, for example, one codeword Cx is “010” in the 12th to 14th bits, while the next codeword Cy is “00100010000010”. Since the 13th bit of one code word Cx is “1” and the 3rd bit of the next code word Cy is “1”, the first to first of the four sets of combined bits 1b described above. Although the three sets of combined bits (000), (001), and (010) can strictly comply with the run-length restriction rule RLL (2, 10), the fourth set of combined bits (100) includes the run-length restriction rule RLL (2, Since 10) is not satisfied, the addition of this combination bit (100) is stopped.

  Then, after adding three sets of coupled bits (000), (001), and (010) between codewords Cx and Cy, three sets of codeword strings {Cx (000) Cy} and {Cx (001) Cy }, {Cx (010) Cy} are input to the DSV value calculation circuit 26 to calculate the DSV values of the three sets of codeword strings, as shown in case 1 shown in FIG. When the coupling bit (000) is added between Cy, the DSV value of the codeword string {Cx (000) Cy} becomes +2, and between the codewords Cx and Cy as in case 2 shown in FIG. When the combined bit (001) is added to the code word, the DSV value of the codeword string {Cx (001) Cy} becomes −4, and the codeword Cx and Cy are between When the combined bit (010) is added, the code word string {Cx (010) Cy} SV value is -6.

  Thereafter, three sets of codeword strings from the DSV value calculation circuit 26 and the corresponding DSV values are input to the DSV value comparison circuit / combination bit selection circuit 27, and the DSV value comparison circuit / combination bit selection circuit 27. And select one set of code word sequences {Cx (000) Cy} having a DSV value = + 2 so that the absolute value of the DSV approaches the most zero among the DSV values of the three sets of code word sequences. The one set of code word strings {Cx (000) Cy} is output from the DSV value comparison circuit / combined bit selection circuit 27 as one determined code word string. In other words, the DSV value comparison circuit / combined bit selection circuit 27 has selected the combined bit (000) corresponding to one decision codeword string {Cx (000) Cy} whose absolute value of DSV is closest to zero. become. Thereafter, the above procedure is repeated following the next code word Cy to obtain one determined code word string {Cx (000) Cy...}.

  Thereafter, one decision codeword string {Cx (000) Cy .........} having a controlled DSV value is generated as a recording signal R (FIG. 1) suitable for recording, and a glass master disc for CD is produced by a laser beam. Or recorded on a CD-R.

  A stamper disk (not shown) is manufactured based on the glass master disk for CD, and a CD is manufactured using this stamper disk.

  From the above, the user uses a CD-ROM drive (not shown) in the personal computer to record 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). Music information to be reproduced and output from the CD-ROM drive and to be recorded on the CD-R is input to a CD-R drive (not shown), and a conventional modulation device 20 provided in the CD-R drive (see FIG. According to 6), the music information to be copied can be directly copied to the CD-R without obtaining the permission of the copyright holder.

  Accordingly, when the 16-bit original music data AD output from the CD-ROM drive is encoded by the conventional modulation device 20 (FIG. 6) provided in the CD-R drive, the music recorded on the CD-R is recorded. Since the information is in the same EFM signal form as the music information recorded on the CD, the copied CD-R can be further copied and will be distributed in large quantities in the world.

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. Yes (see, for example, Patent Document 1).
JP 2001-357536 A (page 4-5, FIG. 4).

  FIG. 8 is a longitudinal sectional view showing an optical disk with copy prevention measures taken as an example of a conventional example.

  The conventional optical disc 100 shown in FIG. 8 is disclosed in the above-described Patent Document 1 (Japanese Patent Laid-Open No. 2001-357536), and briefly described with reference to Patent Document 1, a CD-ROM, In a conventional optical disc 100 in which copy prevention measures are taken for an optical disc such as a DVD-ROM, it is usually based on a run-length restriction rule (described in the same publication as a run-length-suppressing encoding method). Although the concave-convex portion row having a continuous length of 3T to 14T (T is 0.133 μm) is formed, a concave portion having a continuous length shorter than the minimum run length based on the run-length restriction rule in the middle or A convex portion is recorded.

  Specifically, as shown in FIG. 8, the pit A is formed in a convex shape with a length of 1T to 2T, and the 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 pit A and pit B are values that are not based on the run length restriction rule.

  Therefore, in the conventional optical disc 100, the minimum run length 3T is not strictly observed among the run length restriction rules based on the minimum run length 3T and the maximum run length 14T, and is set to 1T to 2T which is a smaller value than this. Thus, the minimum pit length (or minimum land length) on the optical disc 100 is formed smaller than usual.

  Therefore, the technical idea of the above-described conventional optical disc 100 is formed by forming a concavo-convex portion row (pit row) having a continuous length of 3T to 11T based on the run length restriction rule RLL (2, 10) in the CD standard. For example, in the encoding table shown in FIG. 2, the code word C corresponding to the input data word D = 255 is “001000100010010”. However, when it is desired to form a short uneven portion row (pit row) such as 1T, a modified CD can be produced by using the code word C such as “00100110010010” instead.

  When the CD thus modified is reproduced by a commercially available CD player (not shown), the proof pit having a short continuous length of 1T to 2T in the data is a normal pit length (land) of 3T to 11T. The RF signal when 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 has a value of 1T to 2T. Since the pit signal for verification is not included, it cannot be determined whether or not the optical disc being reproduced is an original.

  Further, when the music data recorded on the modified CD is reproduced by a CD-ROM drive in a personal computer (not shown), and the reproduced data is input to the CD-R drive and copied to the CD-R, there is a problem. Music data will be copied without.

  Therefore, copy prevention means based on the prevalence of new players capable of detecting proof pits such as the optical disc 100 is a situation where a large number of players and CD-R drives are already on the market, such as CDs. I have a problem that I cannot apply.

  Furthermore, in order to prohibit copying music information recorded on a CD to a CD-R via a CD-ROM drive in a personal computer (not shown), a copy control CD (Copy Control CD: Although CCCD has been put into practical use, the above-mentioned CCCD may not function effectively depending on the type of CD-ROM drive. Therefore, the technical idea of CCCD is completely against the prohibition of copying to CD-R. No measures were taken.

  Therefore, a CD player that has the above-described technical idea of CCCD and that has a code word string generated while strictly adhering to a predetermined run length restriction rule, is a commercially available CD player that records the code word string. While it can be played back reliably (not shown), the CCCD functions effectively in a CD-ROM drive in a personal computer (not shown) by making the copy recording medium copied from this original CD have a playback failure. There is a need for a modulation device, a modulation method, and a recording medium that can reliably prevent copying of digital information signals recorded on an original CD even if not.

  Alternatively, when the codeword string is generated with the above-described technical concept of CCCD and allowing the minimum run length 3T to the maximum run length 12T without strictly observing the predetermined run length restriction rule, While the original CD on which the row is recorded can be reliably reproduced by a commercially available CD player (not shown), the copy recording medium on which the original CD is copied has a poor reproduction, so that a personal computer (not shown) is used. Therefore, there is a need for a modulation device, modulation method, and recording medium that can reliably prevent copying of digital information signals recorded on an original CD even when CCCD does not function effectively in the CD-ROM drive.

The present invention has been made in view of the above problems, and the invention according to claim 1 converts a p-bit input data word into a q-bit code word and combines r bits between adjacent code words. In a modulation device for adding a bit to generate a codeword string and recording the codeword string on a recording medium,
Copy prevention adding means for adding a copy prevention effect using TOC information recorded in the lead-in area of the recording medium;
modulation means for prefetching at least the next code word following one code word and the next next code word when converting the p-bit input data word into the q-bit code word;
A plurality of sets of coupled bits of r bits between the one codeword and the next codeword are tentatively added while strictly complying with a predetermined run length restriction rule to generate a plurality of sets of codeword strings; In addition, a plurality of sets of combined bits of r bits are strictly adhered to a predetermined run length restriction rule between the next code word in the plurality of code word strings and at least the next next code word. A combined bit adding means for generating a plurality of sets of codeword strings from at least the one codeword to the next codeword,
DSV value calculating means for calculating each DSV value of a large number of codeword strings generated by the combined bit adding means;
Comparison / selection means for selecting one set of code word strings whose absolute value of DSV value is closest to zero among the DSV values of a large number of code word strings obtained by the DSV value calculation means. When,
Using the combined bits added between the one codeword and the next codeword in the one set of codeword strings selected by the comparison / selection means, the combined bits from the one codeword A decision codeword string output means for outputting one decision codeword string finally determined by combining up to the next codeword via
When the input data word is music information and the determined code word string is encoded by adding the music information and specific data that cannot be discerned in the sense of hearing, the specific data is a song section of the music information. It is a modulation device that is inserted into a silent section formed between and between songs.

The invention according to claim 2 converts a p-bit input data word into a q-bit code word, and adds a r-bit combined bit between adjacent code words to generate a code word string, In a modulation device for recording this codeword string on a recording medium,
Copy prevention adding means for adding a copy prevention effect using TOC information recorded in the lead-in area of the recording medium;
modulation means for prefetching at least the next codeword following one codeword when converting the p-bit input data word to the q-bit codeword;
A combination that generates a plurality of sets of codeword strings by temporarily adding a plurality of sets of combined bits of r bits between the one codeword and the next codeword without strictly observing a predetermined run length restriction rule. Bit addition means;
DSV value calculating means for calculating each DSV value of the plurality of sets of codeword strings generated by the combined bit adding means;
Among the DSV values of the plurality of sets of codeword sequences obtained by the DSV value calculation means, one set of the codeword sequences whose absolute value of the DSV value is closest to zero is selected. Comparing / selecting means for outputting one set of the code word strings as a determined code word string,
When the input data word is music information and the determined code word string is encoded by adding the music information and specific data that cannot be discerned in the sense of hearing, the specific data is a song section of the music information. It is a modulation device that is inserted into a silent section formed between and between songs.

The invention according to claim 3 converts a p-bit input data word into a q-bit code word, and adds a r-bit combined bit between adjacent code words to generate a code word string, In a modulation method for recording this codeword string on a recording medium,
A copy prevention adding step of adding a copy prevention effect using TOC information recorded in the lead-in area of the recording medium;
a modulation step of prefetching at least the next codeword following one codeword and the next next codeword when converting the p-bit input data word into the q-bit codeword;
A plurality of sets of coupled bits of r bits between the one codeword and the next codeword are tentatively added while strictly complying with a predetermined run length restriction rule to generate a plurality of sets of codeword strings; In addition, a plurality of sets of combined bits of r bits are strictly adhered to a predetermined run length restriction rule between the next code word in the plurality of code word strings and at least the next next code word. A combined bit adding step for generating a plurality of sets of code word strings from at least one code word to the next next code word,
A DSV value calculating step of calculating each DSV value of the multiple codeword strings generated in the combined bit adding step;
Comparison / selection step of selecting one set of the code word strings in which the absolute value of the DSV value is closest to zero among the DSV values of the plurality of sets of code word strings obtained in the DSV value calculating step When,
Using the combined bits added between the one codeword and the next codeword in the one set of codeword strings selected in the comparison / selection step, the combined bits from the one codeword A decision codeword sequence output step for outputting one decision codeword sequence finally determined by combining up to the next codeword via
When the input data word is music information and the determined code word string is encoded by adding the music information and specific data that cannot be discerned in the sense of hearing, the specific data is a song section of the music information. It is a modulation method characterized by being inserted in a silent section formed between and between songs.

The invention of claim 4 converts a p-bit input data word into a q-bit code word, and adds a r-bit combined bit between adjacent code words to generate a code word string. In a modulation method for recording this codeword string on a recording medium,
A copy prevention adding step of adding a copy prevention effect using TOC information recorded in the lead-in area of the recording medium;
a modulation step of prefetching at least the next codeword following one codeword when converting the p-bit input data word into the q-bit codeword;
A combination that generates a plurality of sets of codeword strings by temporarily adding a plurality of sets of combined bits of r bits between the one codeword and the next codeword without strictly observing a predetermined run length restriction rule. A bit addition step;
A DSV value calculating step of calculating each DSV value of the plurality of sets of codeword strings generated in the combined bit adding step;
Among the DSV values of the plurality of sets of codeword sequences obtained in the DSV value calculation step, one set of the codeword sequences whose absolute value of the DSV value is closest to zero is selected. A comparison / selection step of outputting two sets of the code word strings as a decision code word string,
When the input data word is music information and the determined code word string is encoded by adding the music information and specific data that cannot be discerned in the sense of hearing, the specific data is a song section of the music information. It is a modulation method characterized by being inserted in a silent section formed between and between songs.

  Furthermore, the invention of claim 5 is a recording medium on which the decision codeword string encoded by any one of the modulation apparatus according to claim 1 or 2 or the modulation method according to claim 3 or 4 is recorded. It is.

  According to the modulation device, modulation method, and recording medium of the present invention, a p-bit input data word is converted into a q-bit code word, and an r-bit combined bit is added between adjacent code words. When a word string is generated and this code word string is recorded on a recording medium such as an optical disk, a copy protection effect is added using TOC information recorded in the lead-in area of the optical disk (recording medium). Thus, when the input data word is music information, a decision codeword string obtained by adding and coding music information and specific data that cannot be discerned by hearing is obtained, so that it is difficult to control DSV with a normal modulator. Even in the case of input data words (music information + specific data), a determined code word string is determined so that the DSV value becomes extremely small, and an EFM signal generated by connecting a large number of the determined code word strings is recorded on an optical disk. Therefore, when the user intentionally attempts to copy this optical disk (recording medium) using a CD-ROM drive in a personal computer, the technical idea of CCCD is effective. While a functioning CD-ROM drive can immediately prevent copying, music information is reproduced when a copy recording medium in which a large number of decision code word strings are copied and reproduced on a CD-ROM drive in which the above-described CCCD technical concept does not function. Copy recording medium in which a non-readable section is generated due to the specific data inserted and copied in the silent section formed between the songs and between the songs, and the DSV value also fails and cannot be reproduced. It is possible to prevent copyright infringement of digital information signals above, and to use commercially available optical discs that do not have a copy function. Click drive (e.g. CD player), the decision code word string can be reproduced normally without the original recording medium recorded by chosen number also occur trouble in any way.

  Embodiments of a modulation apparatus, a modulation method, and a recording medium according to the present invention will be described below in detail with reference to FIGS.

  In the modulation apparatus, modulation method, and recording medium according to the present invention, for example, when the CD standard is supported, an input data word of p bits = 8 bits is converted into a code word C of q bits = 14 bits and When a combined bit 1b of r bits = 3 bits is added between the matching code words C and C to generate the EFM signal 1 shown in FIG. 1B, and this EFM signal 1 is recorded on a recording medium such as an optical disk In addition, the TOC information recorded in the lead-in area of the optical disc (recording medium) is used to add a copy prevention effect, thereby providing the technical idea of a copy control CD (CCCD), and following the one code word. And the next codeword at least in advance, and the minimum run length set based on the run length restriction rule RLL (d, k) = RLL (2,10) in the CD standard d + 1) T = 3T to the maximum run length (k + 1) T = 11T, while taking into account the DSV value of the codeword string from one codeword through the next codeword to at least the next codeword After selecting and adding a combination bit 1b between one codeword and the next codeword, a codeword string from one codeword to the next codeword via the combination bit 1b is finally determined. Is output as one determined codeword string, and an EFM signal 1 generated by connecting a large number of the determined codeword strings is recorded on a recording medium such as an optical disk. In this case, Embodiment A described later is used. This applies to the applied modulation apparatus and modulation method.

  Alternatively, similar to the above, it has the technical idea of a copy control CD (CCCD), prefetches at least the next codeword following one codeword, and runs the run length restriction rule RLL (d, k) = Minimum run length (d + 1) set based on RLL (2,10) instead of strictly following the minimum run length (d + 1) T = 3T to the maximum run length (k + 1) T = 11T Allowing T = 3T to maximum run length (k + 2) T = 12T, and taking into account the DSV value of the codeword sequence from one codeword to the next codeword, After selecting and adding the combination bit 1b between them, the code word string from the one code word to the next code word is finally output through the selected combination bit 1b as one determined code word string This The EFM signal 1 generated by connecting a large number of decision codeword strings is recorded on a recording medium such as an optical disk, and this case corresponds to the case of a modulation apparatus and a modulation method to which Embodiment B described later is applied. Is.

  Before describing the modulation apparatus and modulation method according to the present invention, the structure of a recording medium manufactured by applying the modulation apparatus and modulation method will be described first.

9A and 9B are a perspective view and a cross-sectional view showing a recording medium (optical disc) manufactured by applying the modulation apparatus and modulation method according to the present invention,
FIG. 10 is a diagram for explaining a multi-session structure in a recording medium (optical disk) manufactured by applying the modulation apparatus and modulation method according to the present invention.

  As shown in FIGS. 9A and 9B, a recording medium 10 produced by applying the modulation apparatus and modulation method according to the present invention is a reproduction-only type such as a CD (Compact Disc) containing music information. This recording medium (hereinafter referred to as an original CD) is configured as an optical disk, and has one surface of a disk-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. In 11a, the digital information signal is converted into a digital pit row with concave pits and convex lands, and this pit row is engraved on one surface 11a as a spiral or concentric recording track 12. Is recorded. At this time, the digital information signal recorded on the recording track 12 is described later so that the minimum run length satisfies 3T and the maximum run length satisfies 11T with the highest priority by the EFM (Eight to Four Modulation: 8-14 modulation) system. Encoded using the modulation apparatus 30 (FIGS. 11 and 12) to which the embodiment A is applied, or the embodiment B described later is applied so that the minimum run length is 3T and the maximum run length is 12T. It is encoded using the modulation device 50 (FIGS. 16 and 17).

  Further, a metal reflective film 13 and a protective film 14 are sequentially formed on the signal surface of the original CD 10 to form the original CD 10 in a reproduction-only type. The surface 11b side opposite to the one surface 11a of the transparent disk substrate 11 is the side that irradiates the reproduction laser beam Lp.

  As shown in FIG. 10, the digital information signal (EFM signal) recorded on the signal surface of the original CD (optical disc) 10 adopts a multi-session structure consisting of a plurality of sessions. A first session 10a is formed from the inner peripheral side of the optical disc 10 to the latter half of the middle periphery, and a second session 10b is subsequently provided on the outer peripheral side.

  The first session 10a described above includes a first lead-in area 10a1 in which a table of contents, a recording time, and control information relating to the session are recorded, a PCM audio data area 10a2 in which PCM audio data is recorded for a long time, and a first It consists of a first lead-out area 10a3 in which end information of the session 10a is recorded.

  On the other hand, the second session 10b described above includes a second lead-in area 10b1 in which the table of contents, recording time, control information, etc. relating to the session are recorded, and a compressed audio data area 10b2 in which compressed audio data obtained by compressing the PCM audio data is recorded. And the second lead-out area 10a3 in which the end information of the second session 10b is recorded.

  Here, in the present invention, first TOC (Table of Contents) information recorded in the first lead-in area 10a1 of the first session 10a and second TOC information recorded in the second lead-in area 10b1 of the second session 10b. The above-described technical concept of the copy control CD (CCCD) is provided by adding a copy prevention effect using the.

  More specifically, it is recorded in the first and second lead-in areas 10a1 and 10b1 by the Q channel frame structure in the subcode data SD described above with reference to FIGS. 4 (a) and 4 (b). In the first and second TOC information, if the recording track in each of the data areas 102a and 102b is an audio track, 0000 of 4 bits indicates “0”, whereas if the recording track is a data track, 0 100 of 4 bits. CONTROL indicating "4", TNO indicating the song number from 01 to 99 (including the pointer B0 during the session, etc.), and START POSITION (MIN, SEC, FRAME) is recorded.

  At this time, when recording the PCM audio data in the PCM audio data area 10a2 of the first session 10a, the first TOC information recorded in the first lead-in area 10a1 is the data within the CD standard in accordance with the CD standard (IEC908 standard). Specifically, CONTROL is set to “0” to indicate that the PCM audio data area 10a2 is an audio track, and the START POSITION is regular in the order of TNO (song number) in the first session 10a. MIN (minutes), SEC (seconds), and FRAME (frames) set in the above are sequentially recorded, and the compressed audio data of the second session 10b following the first session 10a at the end of the TNO in the first session 10a Poi for searching the region 10b2 Data B0 is recorded.

  On the other hand, when recording compressed audio data in the compressed audio data area 10b2 of the second session 10b, the second TOC information recorded in the second lead-in area 10b1 is non-CD standard data without conforming to the CD standard (IEC908 standard). Specifically, the information corresponding to the TNO (song number) in the first session 10a is set to “4” for the part corresponding to the TNO (song number) and intentionally erroneous information is recorded as a data track. MIN (minutes), SEC (seconds), and FRAME (frames) that were intentionally set incorrectly in the START POSITION without corresponding to the positions of the outer peripheral parts in the order of TNO (music number) in the second session 10b Are sequentially recorded.

  As described above, the first TOC information based on the data within the CD standard is recorded in the first lead-in area 10a1 of the first session 10a, and the second TOC based on the non-CD standard data is recorded in the second lead-in area 10b1 of the second session 10b. When the original CD 10 on which information is recorded is loaded into a CD-ROM drive in a personal computer (not shown) and the original CD 10 is played after the copy software is activated in the personal computer, the light in the CD-ROM drive The pickup first reads each data in the first TOC information recorded in the first lead-in area 10a1 on the inner periphery, and subsequently the second TOC information recorded in the second lead-in area 10b1 by the pointer B0 recorded in the first TOC information. Each data is read. Then, the CD-ROM drive causes a malfunction due to the flawless second TOC information recorded in the second lead-in area 10b1, and the reproduction to the PCM audio data recorded in the PCM audio data area 10a2 of the first session 10a is stopped. In this case, the original CD 10 cannot be copied to the CD-R using a CD-R drive, and the technical idea of CCCD functions effectively.

  On the other hand, depending on the model of the CD-ROM drive in the personal computer, the technical idea of CCCD does not function, that is, the non-standard CD data is recorded in the second TOC information. The PCM audio data recorded in the PCM audio data area 10a2 of the first session 10a may be reproduced. In this case, the original CD 10 can be copied to the CD-R. In order to solve this case, in the present invention, in addition to the above-described CCCD technical idea based on the first and second TOC information, the present invention further supports a CD-ROM drive in which the CCCD technical idea does not function. By applying a new modulation apparatus and modulation method as described below, copy prevention of the original CD 10 to the CD-R is surely prevented.

  Note that a commercially available music CD player (not shown) does not support the multi-session optical disc as described above, and can be reproduced without any problem with respect to the original CD 10 having the technical idea of CCCD. .

  Next, the modulation apparatus and modulation method according to the present invention will be described separately for the case where the embodiment A is applied and the case where the embodiment B is applied.

<In the case of the modulation apparatus and the modulation method to which the embodiment A is applied>
FIG. 11 is a block diagram (part 1) schematically illustrating a modulation device to which the embodiment A is applied in the modulation device and the modulation method according to the invention.
FIG. 12 is a block diagram (part 2) schematically showing a modulation device to which the embodiment A is applied in the modulation device and the modulation method according to the present invention.
FIGS. 13A to 13C show one code word followed by the next code word after strictly complying with the run length restriction rule in the CD standard using the modulation device and the modulation method to which the embodiment A is applied. When a codeword string is generated by adding a coupling bit between the codewords, the next codeword following the one codeword and the next next codeword are pre-read, and then one codeword and the next codeword A pair of combined bits (000) is temporarily added between the next codeword and three sets of combined bits (000), (001), (010) between the next codeword and the next codeword. A diagram for explaining a state in which each DSV value of a large number of codeword strings is calculated when temporarily added,
FIGS. 14A to 14C show one code word followed by the next code word after strictly complying with the run length restriction rule in the CD standard using the modulation device and the modulation method to which the embodiment A is applied. When a codeword string is generated by adding a coupling bit between the codewords, the next codeword following the one codeword and the next next codeword are pre-read, and then one codeword and the next codeword A pair of combined bits (001) is provisionally added between the next codeword and three sets of combined bits (000), (001), (010) between the next codeword and the next codeword. A diagram for explaining a state in which each DSV value of a large number of codeword strings is calculated when temporarily added,
FIGS. 15A to 15C show one code word followed by the next code word after strictly complying with the run length restriction rule in the CD standard using the modulation device and the modulation method to which the embodiment A is applied. When a codeword string is generated by adding a coupling bit between the codewords, the next codeword following the one codeword and the next next codeword are pre-read, and then one codeword and the next codeword A pair of coupled bits (010) is temporarily added between the two and three pairs of coupled bits (000), (001), and (010) between the next codeword and the next codeword. It is a figure for demonstrating the state which calculated each DSV value of many sets of codeword strings, when temporarily added.

  As shown in FIGS. 11 and 12, the modulation device 30 to which the embodiment A is applied is applied to a glass master recording machine (not shown) for producing a CD, and includes a frame synchronization signal generator. 31, a subcode encoder 32, a ROM formatter 33, a changeover switch 34, a CIRC encoder 35, an 8-14 modulation circuit 36, a first combined bit addition circuit 37A, a first DSV value calculation circuit 38A, A two-combination bit adding circuit 37B, a second DSV value calculation circuit 38B, a DSV value comparison circuit / combination bit selection circuit 39, and a decision codeword string output circuit 40 are roughly configured.

  In the modulation device 30 to which the embodiment A is applied, the input data word of p bits = 8 bits is converted into a code word C of q bits = 14 bits, and r bits = between adjacent code words C and C = When the combined bit 1b of 3 bits is added to generate the EFM signal 1 shown in FIG. 1B and this EFM signal 1 is recorded on the original CD 10 (FIGS. 9 and 10), FIG. As described above, the copy prevention effect is added using the first and second TOC information recorded in the first and second lead-in areas 10a1 and 10b1 of the first and second sessions 10a and 10b of the original CD 10. The CCDC has a technical idea, and at least prefetches the next codeword Cy and the next next codeword Cz following the one codeword Cx, and the one codeword Cx and the next codeword Cy In between While observing the length restriction rule RLL (2, 10), a plurality of sets of combined bits 1b are temporarily added to generate a plurality of sets of codeword strings, and the next in the plurality of sets of codeword strings The code word Cy and at least the next code word Cz are also tentatively added with a plurality of 3-bit combination bits 1b while strictly complying with the run-length restriction rule RLL (2, 10), so that one code A large number of code word strings are generated from the word Cx through the next code word Cy to at least the next next code word Cz, and the absolute value of the DSV is the closest to zero among these many code word strings. One set of codeword strings is selected, and using the combined bit 1b added between one codeword Cx and the next codeword Cy in the one set of codeword strings, The next code word Cy is connected through the combined bit 1b. Bound and outputs the determined code word string of one who finally determined, it is recorded EFM signal 1 generated by chosen number of the decision code word string to the original CD 10.

  More specifically, in the modulation device 30 to which the embodiment A is applied, a frame synchronization signal generator 31 for generating the 22-bit frame synchronization signal 1a described with reference to FIG. The frame synchronization signal 1a generated by the frame synchronization signal generator 31 is added to the head of the EFM signal 1 (FIG. 1).

  In addition, the subcode data SD before modulation corresponding to the subcode 1c described with reference to FIG. 1B is converted into the predetermined format shown in FIGS. 4A and 4B by the subcode encoder 32. 8 bits are generated and input to the 8-14 modulation circuit 36.

  Further, 16-bit PCM audio data PCMAD and compressed audio data CAD obtained by compressing the PCM audio data PCMAD by applying a well-known compression technique are prepared in advance as the original music data AD. The data PCMAD is selectively input to a CIRC (Cross Interleaved Reed-Solomon Code) encoder 35 via one terminal of the changeover switch 34. The compressed audio data CAD is selectively input to the CIRC encoder 35 via the other terminal of the changeover switch 34 after being processed by the ROM formatter 33 so as to conform to the format defined by the CD-ROM standard. .

  In the CIRC encoder 35 described above, error correction code processing is performed by combining two Reed-Solomon codes on the PCM audio data PCMAD input via one terminal of the changeover switch 34, and an 8-bit including the error correction code is obtained. The input data words D are sent to the 8-14 modulation circuit 36. The compressed audio data CAD input through the other terminal of the changeover switch 34 is also processed in substantially the same manner as the PCM audio data PCMAD, and each 8-bit input data word D including an error correction code is generated. The signal is sent to the 8-14 modulation circuit 36.

  Next, in the 8-14 modulation circuit 36 described above, the input 8-bit subcode data SD is converted into a 14-bit subcode 1c based on the encoding table shown in FIG. At this time, the subcode 1c is the first and second TOC information recorded in the first and second lead-in areas 10a1 and 10b1 in the multi-session original CD (optical disc) 10 described above with reference to FIG. And added to the PCM audio data PCMAD recorded in the PCM audio data area 10a2 and the compressed audio data CAD recorded in the compressed audio data area 10b2 after the frame synchronization signal 1a of the EFM signal 1 (FIG. 1). Is.

  Further, in the 8-14 modulation circuit 36, the input PCM audio data PCMAD, the compressed audio data CAD, and the 8-bit input data word D such as an error correction code are converted into 14-bit data based on the encoding table shown in FIG. When sequentially converting to codeword C, unlike the conventional example described above with reference to FIG. 6, one codeword Cx is read, and the next codeword Cy following the one codeword Cx and the next next The code word Cz is prefetched at least.

  In the following, the case of prefetching to the next code word Cy and the next next code word Cz following one code word Cx will be described. However, the present invention is not limited to this, but illustration is omitted here. It is also possible to prefetch a code word further ahead of the next code word Cz.

  Then, one code word Cx and the next code word Cy are input from the 8-14 modulation circuit 36 to the first combined bit adding circuit 37A, and after the next code word Cy is output, the next next code word Cz is input from the 8-14 modulation circuit 36 to a second combined bit addition circuit 37B described later.

  Next, in the first combined bit addition circuit 37A, a 3-bit value is maintained while strictly observing 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. Four candidates (000), (001), (010), and (100) are prepared as candidates for the combined bit 1b. Also in this embodiment A, as in the conventional example, two or more “1” s appear continuously in the groups (011), (101), (110), and (111) other than the above four groups, or Since “1” and “0” appear alternately, they are deleted because they do not satisfy the minimum run length 3T.

  Then, in order to combine one code word Cx input into the first combined bit addition circuit 37A and the next code word Cy following this, four sets of combined bits (000 between the code words Cx and Cy (000) ), (001), (010), and (100) are temporarily added to generate a plurality of sets of codeword strings.

  At this time, as shown in FIGS. 13 to 15, when one code word Cx and the next code word Cy are respectively set to the same value as the conventional one in order to easily understand the gist of the embodiment A, The codeword Cx is “010” in the 12th to 14th bits, while the next codeword Cy is “00100010000010”. Since the 13th bit of one code word Cx is “1” and the 3rd bit of the next code word Cy is “1”, the first to first of the four sets of combined bits 1b described above. Three sets of combined bits (000), (001), and (010) are satisfied because they satisfy the minimum run length 3T to the maximum run length 11T, and the fourth set of combined bits (100) sets the minimum run length 3T. Since it is not satisfied, addition is stopped.

  Then, after adding three sets of coupled bits (000), (001), and (010) between codewords Cx and Cy, three sets of codeword strings {Cx (000) Cy} and {Cx (001) Cy }, {Cx (010) Cy} are input to the first DSV value calculation circuit 38A to calculate the respective DSV values of the three sets of codeword strings, as shown in FIG. 13, coupled bits between the codewords Cx and Cy When (000) is added, the DSV value of the codeword string {Cx (000) Cy} becomes +2, and when a coupling bit (001) is added between the codewords Cx and Cy as shown in FIG. , The DSV value of the codeword sequence {Cx (001) Cy} is −4, and when a coupling bit (010) is added between the codewords Cx and Cy as shown in FIG. 15, the codeword sequence { The DSV value of Cx (010) Cy} is −6. The steps up to this stage are the same as those of the conventional example described above with reference to FIGS. 6 and 7. In the conventional example, at this stage, a set of codeword strings {Cx (000 ) Cy} is selected as one finally determined codeword string, but in the embodiment A, as described above, the next codeword Cy and the next next codeword Cz following one codeword Cx are selected. Therefore, one codeword Cx and the next codeword are considered in consideration of the DSV value when the codeword Cx is connected to the next codeword Cz through the next codeword Cy. After selecting and adding the combined bit 1b to Cy, the code word string from one code word Cx to the next code word Cy through the combined bit 1b is finally determined.

  Therefore, a second combination bit is added to three sets of codeword strings {Cx (000) Cy}, {Cx (001) Cy}, and {Cx (010) Cy} obtained by calculating each DSV value by the first DSV value calculation circuit 38A. The signal is input to the circuit 37B.

  Similarly to the first combined bit adding circuit 37A, the second combined bit adding circuit 37B described above can be (000), (001), (000), (001), (3) as candidates for the 3 bit combined bits 1b satisfying the minimum run length 3T to the maximum run length 11T. Four sets of (010) and (100) are prepared.

  Then, in the second combined bit addition circuit 37B, three sets of code word strings {Cx (000) Cy}, {Cx (001) Cy}, {Cx (010) Cy} input here are input here. From the case of the first combined bit adding circuit 37A, four sets of combined bits (000), (001), (010), and (100) are temporarily added to the next code word Cz. Also, a large number of code word strings having a large number of sets are generated. At this time, a large number of codeword strings are encoded in a branching structure (tree structure), so that all the codeword strings are commonly shared from one codeword Cx to the next codeword Cy to the next next codeword Cz. Codeword strings up to

  Here, as illustrated in FIGS. 13 to 15, the next code word Cy is “00100010000010” as described above, while the next code word Cz is “0010001000010”. Since the 13th bit of the next code word Cy is “1” and the 3rd bit of the next next code word Cz is “1”, the first of the four sets of combined bits 1b is the first. Although the third set of combined bits (000), (001), and (010) satisfy the minimum run length 3T to the maximum run length 11T, the fourth set of combined bits (100) does not satisfy the minimum run length 3T. Stop adding.

  Between the three sets of codeword strings {Cx (000) Cy}, {Cx (001) Cy}, {Cx (010) Cy} and the next next codeword Cz inputted here, 3 After adding a set of combination bits (000), (001), and (010), a total of nine codeword strings {Cx (000) Cy (000) Cz}, {Cx (000) Cy (001) Cz}, {Cx (000) Cy (010) Cz}, {Cx (001) Cy (000) Cz}, {Cx (001) Cy (001) Cz}, {Cx (001) Cy (010) Cz} , Cx (010) Cy (000) Cz}, {Cx (010) Cy (001) Cz}, {Cx (010) Cy (010) Cz} are input to the second DSV value calculation circuit 38B and nine sets of codes are input. Each DSV value of the word string is calculated.

Here, the DSV value of the codeword string {Cx (000) Cy (000) Cz} is −3 as in the case 11 shown in FIG.
The DSV value of the code word string {Cx (000) Cy (001) Cz} becomes +3 as in the case 12 shown in FIG.
The DSV value of the codeword string {Cx (000) Cy (010) Cz} is +5 as in the case 13 shown in FIG.

Further, the DSV value of the code word string {Cx (001) Cy (000) Cz} becomes +1 as in the case 21 shown in FIG.
The DSV value of the code word string {Cx (001) Cy (001) Cz} is −5 as in the case 22 shown in FIG.
As in the case 23 shown in FIG. 14C, the DSV value of the codeword string {Cx (001) Cy (010) Cz} is −7.

Further, as in the case 31 shown in FIG. 15A, the DSV value of the codeword string {Cx (010) Cy (000) Cz} becomes −1,
The DSV value of the codeword string {Cx (010) Cy (001) Cz} is −7 as in the case 32 shown in FIG.
As in the case 33 shown in FIG. 15C, the DSV value of the code word string {Cx (010) Cy (010) Cz} is −9.

  Thereafter, nine sets of code word strings from the second DSV value calculation circuit 38B and the corresponding DSV values are input to the DSV value comparison circuit / combination bit selection circuit 39, and the DSV value comparison circuit / combination bit selection circuit 39 39, the code word string {Cx (001) Cy (000) Cz} having the DSV value of the DSV value that is closest to zero among the DSV values of the nine sets of code word strings = + 1, or the DSV value = One set of codeword strings {Cx (010) Cy (000) Cz} having −1 is selected and input to the determined codeword string output circuit 40.

  When the DSV value comparison circuit / combined bit selection circuit 39 selects the code word string, if the DSV absolute value of the code word string is the same value, the code word string of the DSV value on the + side is adopted. If the codeword string of the DSV value on the negative side is adopted in advance in the modulation device 30 described above, the codeword string only on the positive side or the one side is automatically selected. The combined bit 1b corresponding to the code word string on only one side can be selected.

  Next, the decision codeword string output circuit 40 adds between one codeword Cx and the next codeword Cy in one set of codeword strings selected by the DSV value comparison circuit / combined bit selection circuit 39. One determined codeword string {Cx (001) Cy} finally determined by combining one codeword Cx to the next codeword Cy through the combined bit 1b using the combined bit 1b One of the decision codeword strings {Cx (010) Cy} is output. In other words, this is equivalent to a state in which the combined word 1b between the code words Cy and Cz and the code word Cz are removed from one set of code word strings selected by the DSV value comparison circuit / combined bit selection circuit 39.

  That is, the codeword string {Cx (001) Cy (000) Cz} having the DSV value = + 1, or the codeword string {Cx (010) having the DSV value = −1, which is input to the determined codeword string output circuit 40. Cy (000) Cz} is a combination bit 1b added between codewords Cx and Cy is (001) or (010), and from one codeword Cx through the next codeword Cy to the next next The combination bit 1b added between the code words Cx and Cy is selected so that the absolute value of the DSV when the DSV value of the code word string up to the code word Cz is taken into consideration is closest to zero.

  On the other hand, as in the conventional example described with reference to FIG. 6, the coupling bit 1b is set between the code words Cx and Cy using the conventional modulator 20 that pre-reads only one code word Cx and the next code word Cy. In the case of addition, first, as shown in FIG. 6, one decision codeword sequence {Cx (010) Cy} having a DSV value of +2 is obtained, and thereafter, one decision codeword sequence {Cx (010) ) Cy} is connected to the code word Cz as shown in FIGS. 13A to 13C, and each DSV value in FIGS. 13A to 13C pre-reads the next code word Cz described above. The DSV value obtained from the codeword sequence {Cx (001) Cy (000) Cz} having a DSV value of +1 or the codeword sequence {Cx (010) Cy (000) Cz} having a DSV value of -1 is sometimes obtained. It becomes large on the + side or-side.

  Thereafter, in the embodiment A, the determined codeword sequence {Cx (001) Cy ...} or the determined codeword sequence {Cx (010) Cy ...} that is controlled so that the DSV value is the best is suitable for recording. The recorded signal R is converted into a recorded signal R (FIG. 1) and recorded on a glass master (not shown) for CD by a laser beam. Then, a stamper disk (not shown) is manufactured based on the glass master disk for CD, and the original CD 10 of the present embodiment as shown in FIGS. 9A and 9B is used by using this stamper disk. Is making.

  The basic operation of the modulation device 30 and the modulation method to which the embodiment A is applied has been described with specific examples. However, in order to make the explanation easier to understand, in the calculation of the DSV value, the code word string {Cx (000) Cy}, {Cx (000) Cy (000) Cz}, {Cx (000) Cy (000) ) Cz..., Such as the codeword sequence that has already been determined, is expressed so as to perform the calculation again. As a result, if all the code words Cx, Cy, Cz... Are not inputted, it is possible not only to calculate the DSV value but also to output the determined code word string. A DSV value storage circuit (not shown) is provided in the DSV value calculation circuit 38A, 38B or the DSV value comparison circuit / combined bit selection circuit 39 for the DSV value of the determined code word string. If it is avoided and at least three code words are input, one determined code word string can be obtained.

  In order to generate a code word string by adding a 3-bit combined bit 1b having the best DSV value between adjacent code words C and C from the above, the next code word Cy following one code word Cx and When the modulation device 30 that generates at least the next codeword Cz by prefetching the next codeword Cz is used, the DSV value is the highest among a large number of codeword strings as shown in FIGS. Can take small values.

  On the other hand, when the conventional modulation device 20 (FIG. 6) that does not prefetch the next next codeword Cz is used, the next next codeword Cz is prefetched as shown in FIGS. It is clear from the above that the DSV value is larger than that in the case where the conventional modulation device 20 (FIG. 6) is used as the DSV value of the codeword string generated by the modulation device 30 to which the embodiment A is applied. It can be a small value compared to.

<In the case of the modulation apparatus and the modulation method to which the embodiment B is applied>
FIG. 16 is a block diagram (part 1) schematically showing a modulation device to which the embodiment B is applied in the modulation device and modulation method according to the present invention.
FIG. 17 is a block diagram (part 2) schematically showing a modulation device to which the embodiment B is applied in the modulation device and the modulation method according to the present invention.
FIGS. 18A and 18B are diagrams for explaining a case where encoding is performed with the maximum run length not satisfying the run length restriction rule in the CD standard using the modulation apparatus and the modulation method to which the embodiment B is applied. FIG.

  As shown in FIGS. 16 and 17, the modulation device 50 to which the embodiment B is applied is applied to a glass master recording machine (not shown) for producing a CD, and includes a frame synchronization signal generator. 51, subcode encoder 52, ROM formatter 53, changeover switch 54, CIRC encoder 55, 8-14 modulation circuit 56, combined bit addition circuit 57, DSV value calculation circuit 58, and DSV value comparison circuit It is schematically configured with a combined bit selection circuit 59.

  In the modulation apparatus 50 to which the embodiment B is applied, the input data word of p bits = 8 bits is converted into the code word C of q bits = 14 bits, and r bits = between adjacent code words C and C = When the combined bit 1b of 3 bits is added to generate the EFM signal 1 shown in FIG. 1B and this EFM signal 1 is recorded on the original CD 10 (FIGS. 9 and 10), FIG. As described above, the copy prevention effect is added using the first and second TOC information recorded in the first and second lead-in areas 10a1 and 10b1 of the first and second sessions 10a and 10b of the original CD 10. In addition to the technical idea of CCCD, a run length restriction rule RLL (d, k) = RLL (2,10) in the CD standard between one codeword Cx and the next codeword Cy following this. Based on The set minimum run length (d + 1) T = 3T to the maximum run length (k + 1) T = 11T is not strictly observed, and instead, the minimum run length (d + 1) T = 3T to the maximum run length (k + 2) T = A combined bit 1b of r bits = 3 bits is temporarily added so as to allow 12T, and a plurality of sets of codeword strings are generated, and the DSV absolute value is the lowest among these sets of codeword strings. One set of codeword strings close to the output, and the one set of codeword strings is output as one finally determined codeword string, and an EFM signal generated by connecting a number of the determined codeword strings 1 is recorded on the original CD10.

  More specifically, in the modulation device 50 to which the embodiment B is applied, a frame synchronization signal generator 51 for generating the 22-bit frame synchronization signal 1a described with reference to FIG. The frame synchronization signal 1a generated by the frame synchronization signal generator 51 is added to the head of the EFM signal 1 (FIG. 1).

  Further, the subcode data SD before modulation corresponding to the subcode 1c described with reference to FIG. 1B is converted into the predetermined format shown in FIGS. 4A and 4B by the subcode encoder 52. 8 bits are generated and input to the 8-14 modulation circuit 56.

  Further, 16-bit PCM audio data PCMAD and compressed audio data CAD obtained by compressing the PCM audio data PCMAD by applying a well-known compression technique are prepared in advance as the original music data AD. The data PCMAD is selectively input to a CIRC (Cross Interleaved Reed-Solomon Code) encoder 55 via one terminal of the changeover switch 54. The compressed audio data CAD is selectively input to the CIRC encoder 55 via the other terminal of the changeover switch 54 after being processed by the ROM formatter 53 so as to conform to the format defined by the CD-ROM standard. .

  In the CIRC encoder 55 described above, error correction code processing is performed by combining two Reed-Solomon codes for the PCM audio data PCMAD input via one terminal of the changeover switch 54, and an 8-bit including the error correction code is performed. The input data words D are sent to the 8-14 modulation circuit 56. The compressed audio data CAD input via the other terminal of the changeover switch 54 is also processed in substantially the same manner as the PCM audio data PCMAD, and each 8-bit input data word D including an error correction code is generated. It is sent to the 8-14 modulation circuit 56.

  Next, in the 8-14 modulation circuit 56 described above, the input 8-bit subcode data SD is converted into a 14-bit subcode 1c based on the encoding table shown in FIG. At this time, the subcode 1c is the first and second TOC information recorded in the first and second lead-in areas 10a1 and 10b1 in the multi-session original CD (optical disc) 10 described above with reference to FIG. And added to the PCM audio data PCMAD recorded in the PCM audio data area 10a2 and the compressed audio data CAD recorded in the compressed audio data area 10b2 after the frame synchronization signal 1a of the EFM signal 1 (FIG. 1). Is.

  Further, in the 8-14 modulation circuit 56, the input PCM audio data PCMAD, the compressed audio data CAD, and the 8-bit input data word D such as an error correction code are converted into 14-bit data based on the encoding table shown in FIG. One code word Cx, the next code word Cy, the next next code word Cz, and so on are sequentially read in order to be converted into the code word C, in other words, following one code word Cx. The next code word Cy is prefetched at least.

  Then, one codeword Cx and codeword Cy are input from the 8-14 modulation circuit 56 to the combined bit adding circuit 57, and the codeword Cz has the best DSV value between the codeword Cx and the codeword Cy. The combined bit 1b is added to obtain one decision code word string, and then input from the 8-14 modulation circuit 56 to the combined bit addition circuit 57.

  The combined bit adding circuit 57 is different from the combined bit adding circuit 22 in the conventional modulation apparatus 20 described above with reference to FIG. 6, and is based on the run length restriction rule RLL (2, 10) in the CD standard. Instead of strictly adhering to the set minimum run length 3T to maximum run length 11T, a combined bit of 3 bits between adjacent code words C and C so as to allow the minimum run length 3T to the maximum run length 12T instead. 1b is added, and in this combined bit adding circuit 57, four sets of (000), (001), (010), and (100) are prepared as candidates for the combined bit 1b of 3 bits. ing. In this embodiment B as well, as in the conventional example, two or more “1” s appear continuously in the groups (011), (101), (110), and (111) other than the above four groups, or , “1” and “0” appear alternately so that the minimum run length 3T is not satisfied, and therefore, “1” and “0” are deleted.

  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) as described above are not strictly observed. Instead of the minimum run length 3T to the maximum run length 12T, when the minimum run length is (d + 1) T = 3T, the logical value “1” between “1” and “1” in the code word C is “0”. The minimum number is d = 2, while the maximum run length is (k + 2) T = 12T, and the number of “0” s between the logical values “1” and “1” in the codeword C is A maximum of k + 1 = 11 is included.

  Then, in order to combine one code word Cx input into the combined bit adding circuit 57 and the code word Cy subsequent thereto, four sets of combined bits (000), (001) between the code words Cx and Cy. ), (010), and (100) are temporarily added to generate a plurality of sets of codeword strings.

  At this time, if the maximum run length 12T that does not satisfy the maximum run length 11T on the CD standard is allowed, the following characteristics can be obtained. As shown in FIGS. 18A and 18B, 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 as, for example, a code word “10000100000000” obtained by converting an 8-bit input data word “001” into 14 bits. Since the 13th bit of the code word Cx is “1” and the first bit of the code word Cy is “1”, the first set of the four sets of the combined bits 1b described above. Although the combined bit (000) of the above can allow the minimum run length 3T to the maximum run length 12T, the other three sets of combined bits (001), (010), (100) do not satisfy the minimum run length 3T. The addition of the combination bits (001), (010), (100) is stopped.

  Then, after adding a first combination bit (000) between the code words Cx and Cy, the code word string {Cx (000) Cy} is input to the DSV value calculation circuit 58 to calculate the DSV value. When the coupling bit (000) is added between the code words Cx and Cy as in the cases 11 and 12 shown in 18 (a) and (b), the DSV value of the code word string {Cx (000) Cy} is The first set of codeword strings {Cx (000) Cy} and the corresponding DSV value = + 4 are input to the DSV value comparison circuit / combined bit selection circuit 59.

  Thereafter, since the DSV value comparison circuit / combined bit selection circuit 59 has only one set of input code word strings, the DSV value comparison and selection of the combined bit 1b having the best DSV value are performed immediately. The codeword string {Cx (000) Cy} is output as one finally determined codeword string {Cx (000) Cy}.

  Next, after obtaining one decision codeword string {Cx (000) Cy}, a DSV value between the codeword Cy and the codeword Cz in the one decision codeword string {Cx (000) Cy} is obtained. Is added to the combined bit adding circuit 57 from the 8-14 modulation circuit 56.

  Here, as shown in FIGS. 18A and 18B, the code word Cz described above is input as a code word “10000000000010010” obtained by converting an 8-bit input data word “249” into 14 bits, for example. .

  In the above-described combined bit adding circuit 57, four sets of combined bits (000), (001), between the code word Cy and the code word Cz in one determined codeword string {Cx (000) Cy}, (010) and (100) are temporarily added to generate a plurality of sets of codeword strings.

  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 of the four combined bits 1b described above (000 ), (100) satisfy the minimum run length 3T to the maximum run length 12T, but the other two sets of combined bits (001), (010) do not satisfy the minimum run length 3T, so these combined bits (001) , (010) addition is stopped.

  Then, as in the case 11 shown in FIG. 18A, a combined bit (000) is added between the code word Cy in one determined code word string {Cx (000) Cy} and the code word Cz. In the code word sequence {Cx (000) Cy (000) Cz} obtained in this way, the number of “0” s from the seventh bit to the third bit of the combined bit (000) in the code word Cy is 11 consecutive. Therefore, the maximum run length 12T is included.

  On the other hand, as in the case 12 shown in FIG. 18B, a coupling bit (100) is added between the code word Cy in one determined code word string {Cx (000) Cy} and the code word Cz. In the code word string {Cx (000) Cy (100) Cz} obtained in this way, the number of “0” s from the seventh bit to the first bit of the combined bit (100) in the code word Cy is eight consecutive. 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.

  Thereafter, two sets of codeword strings {Cx (000) Cy (000) Cz} and {Cx (000) Cy (100) Cz} obtained in the combined bit addition circuit 57 are input to the DSV value calculation circuit 58. Then, when each DSV value of each codeword string is calculated, the DSV value of the codeword string {Cx (000) Cy (000) Cz} becomes −1 as in the case 11 shown in FIG. As in the case 12 shown in FIG. 18B, the DSV value of the code word string {Cx (000) Cy (100) Cz} is +9, and these two sets of code word 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 59.

  Next, in the DSV value comparison circuit / combined bit selection circuit 59, the DSV values of the two sets of codeword strings {Cx (000) Cy (000) Cz}, {Cx (000) Cy (100) Cz} Among them, a set of code word sequences {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 sequence is finally selected. One determined codeword sequence {Cx (000) Cy (000) Cz} is output, and then the above procedure is repeated following the codeword Cz, so that one determined codeword sequence {Cx (000) Cy ( 000) Cz ....}

  By the way, in order to generate the maximum run length 12T in the combination of the code word C and the combined bit 1b, two code words C adjacent to each other with the combined bit 1b sandwiched between them as "Cy and Cz" in FIG. However, the number of “0” s including the combined bit 1b when the combined bit 1b is added can be 11 consecutive.

  The basic operation of the modulation device 50 and the modulation method to which the embodiment B is applied has been described above with specific examples. However, in order to make the explanation easier to understand, in the calculation of the DSV value, the code word string {Cx (000) Cy}, {Cx (000) Cy (000) Cz}, {Cx (000) Cy (000) ) Cz..., Such as the codeword sequence that has already been determined, is expressed so as to perform the calculation again. As a result, if all the code words Cx, Cy, Cz... Are not inputted, it is possible not only to calculate the DSV value but also to output the determined code word string. A DSV value storage circuit (not shown) is provided in the DSV value calculation circuit 58 or DSV value comparison circuit / combined bit selection circuit 59 for the DSV value of the determined code word string, and avoids duplication of DSV value calculation. If at least two code words are input, one determined code word string can be obtained.

  Thereafter, the decision codeword string {Cx (000) Cy (000) Cz...} Whose 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. Recorded on a glass master (not shown). Then, a stamper disk (not shown) is manufactured based on the glass master disk for CD, and the original CD 10 of the present embodiment as shown in FIGS. 9A and 9B is used by using this stamper disk. Is making.

  When the modulation device 50 capable of generating the maximum run length 12T is used to generate the code word string by adding the three combined bits 1b having the best DSV value between the adjacent code words C and C from the above, As in case 11 shown in FIG. 18A, the code word string including the maximum run length 12T can take the smallest DSV value.

  On the other hand, when the conventional modulator 20 (FIG. 6) that 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. It is clear from the above that the DSV value becomes larger than that. Here, the maximum run length 12T has been described as an example in which the run length restriction rule on the CD standard is not strictly observed. However, the above-described modulation is also applied to a long run length of 13T or more, or conversely, a short run length of 2T or less. The present invention can be applied to the device 50, and the DSV value of the codeword string can be made smaller than that in the case where the conventional modulation device 20 (FIG. 6) is used. However, as described in the section of the prior art, it is not preferable to allow an extremely short run length or an extremely long run length from the viewpoint of transmission characteristics.

  It should be noted that a part of the modulation device 50 (FIGS. 16 and 17) to which the embodiment B is applied is modified, and one symbol is used in the same manner as the case of the modulation device 30 to which the embodiment A is applied (FIGS. 11 and 12) It is also possible to configure to prefetch at least the next codeword following the word and the next next codeword. In the case of this modification, the technical idea of a copy control CD (CCCD) is provided, at least the next code word following one code word and the next next code word are prefetched, and the CD standard is used. The minimum run length (d + 1) T = 3T to the maximum run length (k + 1) T = 11T set based on the run length restriction rule RLL (d, k) = RLL (2,10) of Instead of the minimum run length (d + 1) T = 3T to the maximum run length (k + 2) T = 12T, and the codeword string from one codeword to the next codeword to at least the next next codeword The combination bit 1b between one codeword and the next codeword is selected and added while considering the DSV value of the code, and then the code from one codeword to the next codeword through the combination bit 1b Final word sequence And one output as determined code word string with the EFM signal 1 generated by chosen number of the decision code word string in which may be recorded on a recording medium such as an optical disk.

  By the way, when encoding is performed using the conventional modulation device 20 (FIG. 6), the DSV value of the code word string may fluctuate greatly periodically when the DSV value continues to increase over a certain period. is there. This is because the decision codeword corresponding to the first codeword Cx is the same as when the DSV value rises to the right, that is, when the input codeword Cx, Cy, Cz. If the polarity of the column is reversed, the DSV value may decrease to the right, that is, tend to increase negatively. As a result, when a signal recorded using the conventional modulation apparatus 20 (FIG. 6) is reproduced, a specific frequency component increases in the reproduction signal of the code word string, and stable reproduction is impaired. On the other hand, in the case of the modulation device 30 to which the embodiment A is applied (FIGS. 11 and 12) or the modulation device 50 to which the embodiment B is applied (FIGS. 16 and 17), stable reproduction is maintained. it is obvious. Hereinafter, input data corresponding to a specific codeword that causes such a difference is referred to as specific data.

  Then, by applying the technical idea of the modulation method 30 (FIGS. 11 and 12) and the modulation method to which the embodiment A is applied, at least the next code is transmitted from one code word Cx to the next code word Cy. When the code word string generated from specific data is recorded on the original CD 10 (FIGS. 9 and 10) while pre-reading up to the word Cz and strictly observing the minimum run length 3T to the maximum run length 11T, or Embodiment B The modulation device 50 (FIGS. 16 and 17) to which is applied, and the codeword sequence generated from the specific data while allowing the minimum run length 3T to the maximum run length 12T by applying the technical idea of the modulation method is converted into the original CD 10 ( When recorded in FIGS. 9 and 10), the DSV value of the recorded code word string is extremely small so that reproduction failure does not occur, but a copy of this original CD 10 is copied. In recording media, it is clear that the components of a particular frequency increases to the reproduced signal because the variation becomes large DSV value of a specific data portion of the above original CD 10.

  This is shown in FIG.

  FIG. 19 is a diagram showing the difference in frequency spectrum accompanying the change in the DSV value of the codeword string between the case of the original CD of this embodiment according to the present invention and the case of a CD-R in which the original CD is copied.

  As shown in FIG. 19, the reproduction frequency spectrum of the code word string of the specific data portion recorded on the original CD 10 is gently attenuated in the low frequency portion, while the original CD 10 is converted to the conventional modulation device 20. In the reproduction frequency spectrum of the code word string of the specific data portion when the copy recording medium (CD-R) copied by (FIG. 6) is reproduced, the component of the specific frequency is increased in the low frequency portion, and copy recording is performed. The reproduction of the medium (CD-R) becomes unstable.

  When the recording track 12 recorded on the original CD 10 is reproduced by a commercially available CD player (not shown), the DSV value of the specific data portion is small, so that no error occurs in the reproduced data. On the other hand, as shown in FIGS. 13 (a) to 13 (c), 14 (b), (c), 15 (b), (c), and FIG. When an input data word D occurs for a certain period, the DSV value of the code word string has a large fluctuation amount in an optical disk manufactured by the conventional modulation device 20 (FIG. 6), and one frame length or 2 of the code word string. Since it fluctuates in a cycle based on the frame length, a reproduction failure occurs.

  Similarly, the user copies the original CD 10 on which the PCM audio data PCMAD (FIG. 11) including the specific data is recorded to a copy recording medium (CD-R) using a CD-R drive in a personal computer (not shown). In this case, since the conventional modulation device 20 (FIG. 6) is provided in the CD-R drive as described above, the PCM audio data PCMAD (FIG. 11) obtained by reproducing the original CD 10 is used. If input to the CD-R drive, a codeword string is generated by prefetching only one codeword Cx and the next codeword Cy and adding the combined bit 1b in the conventional modulator 20 (FIG. 6). For this reason, the DSV value of the copied code word string has a variation amount larger than that when the modulation device 30 (FIGS. 11 and 12) or the modulation device 50 (FIGS. 16 and 17) is used. Listening, and 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 a CD-ROM drive in a personal computer (not shown), the reproduction signal is operated by the binarization circuit, tracking or focus. The component of a specific frequency that adversely affects the servo or the like increases, and the reproduction becomes unstable or cannot be reproduced. Thereby, when the original CD 10 is copied to a copy recording medium (CD-R), copyright infringement on the digital information signal can be prevented. As described in the prior art section of Japanese Patent Laid-Open No. Hei 6-197024, it is known that a large amount of variation in the DSV value of the code word string described above adversely affects the stability of the regenerator. The details are omitted.

  Here, in the modulation device 30 to which the embodiment A is applied (FIGS. 11 and 12), the modulation method or the modulation device 50 to which the embodiment B is applied (FIGS. 16 and 17), and the modulation method, p-q modulation should be performed. When the input data word D is music information (PCM audio data) and the p-bit input data word D is converted into the q-bit code word C, the AC signal or the specific data of the DC signal that cannot be discerned in terms of audibility is encoded. If the encoded specific data is added to the music information and used, it is further effective for copy prevention. This case will be described with reference to FIGS. 20 and 21. FIG.

FIG. 20 is a schematic diagram for explaining a silent section between songs in a general CD.
FIG. 21 explains the case of a specific data insertion mode in which specific data that cannot be discriminated in the sense of hearing is inserted into a music section of music information and a silent section formed between songs in the recording medium according to the present invention. It is a schematic diagram for.

  Here, the specific data that cannot be discriminated from the sense of hearing is stored in the music section of the music information on the original CD 10 (FIGS. 9 and 10) serving as the recording medium according to the present invention and in the silent section formed between the songs. Before explaining the case of recording by inserting into a CD, a silent section in the case of a general CD (Compact Disc) containing music information will be explained first as reference material for this.

  That is, as shown in FIG. 20, in the case of a general CD containing music information, in accordance with the CD standard “Red Book”, the TOC (not shown) formed in the lead-in area (not shown) formed on the inner circumference side. In Table of Contents information, the start address of each song is recorded in advance as the index information of the music information, and this start address is equivalent to the START POSITION (recording start position) in the TOC information shown in FIG. It is. Further, a plurality of songs recorded in the data area on the CD track are recorded with a song number, an index number, an address, etc. for each song as shown in the figure.

  More specifically, when a plurality of songs recorded on a CD are generalized using n (where n is a natural number of 2 or more) and displayed, for example, the (n-1) th of the plurality of songs. A silent section is formed between the first song and the nth song.

  Also, the song number n-1 corresponding to the n-1th song is assigned to the n-1th song from the performance end position (not shown) immediately after the performance of the n-2th song (not shown) is finished. The performance end position of music number n-1 corresponding to the (n-1) th song is recorded between the n-1th song and the nth song. It is set in a silent section formed between them. Further, the music number n corresponding to the nth music is recorded following the performance end position of the music number n-1 corresponding to the (n-1) th music.

  In addition, the n-1th song and the nth song can be assigned index numbers from 01 to 99 in order to indicate the order of movement in each song. The index number 01 (-99) is recorded from the position of the start address (not shown) of the (n-1) th song to the performance end position of the song number n-1 of this song, while n The index number 01 (-99) in the tune is recorded from the position of the start address of the nth song to the performance end position (not shown) of the song number n of this song. At this time, the start address (not shown) of the (n-1) th song and the start address of the nth song are within the silent section between the songs and are located before the leading end where the performance of each song starts. Is recorded.

  In addition, in the 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.

  As described above, the (n-1) th song ends at the performance end position of the song number n-1 of this song. On the other hand, the nth song is started from the position of the start address of this song.

  Here, when the song number, index number, and start address are recorded for each song corresponding to a plurality of songs recorded in the data area on the track as in the above-described CD, the recording according to the present invention is performed. In the original CD 10 (FIGS. 9 and 10) serving as a medium, for example, a silent section (with index number 00) formed in the (n-1) th song and between the (n-1) th song and the nth song. The specific data of the alternating current signal or direct current signal that cannot be discerned in terms of perception is inserted and recorded in the (interval) and the nth music piece based on the specific data insertion form shown in FIG.

  More specifically, when the input data word D to be p-q modulated is music information (PCM audio data), PCM audio data and AC signal or DC signal specific data that cannot be discerned from the sense of hearing are preliminarily stored. The input data word D is generated by addition, and the modulation device 30 (FIGS. 11 and 12) to which the embodiment A is applied to the input data word D or the modulation device 50 to which the embodiment B is applied (FIG. 16). , FIG. 17).

  That is, the PCM audio data is added to the modulation device 30 (FIGS. 11 and 12) to which the embodiment A is applied by adding specific data consisting of an AC signal of about 22.05 KHz, for example, a signal that cannot be discerned by hearing. The signal is input to the 8-14 modulation circuit 56 or the 8-14 modulation circuit 56 provided in the modulation device 50 (FIGS. 16 and 17) to which the embodiment B is applied.

  Then, when the input data word D obtained by adding the PCM audio data and the specific data composed of, for example, an AC signal of about 22.05 KHz is converted into a 14-bit code word C, the above-described modulation device 30 (FIGS. 11 and 12). ), The minimum run length 3T to the maximum run length 11T are strictly observed, and at least the next code word Cy and the next next code word Cz following the one code word Cx are prefetched to obtain a DSV value. 1 is added to generate a single determined codeword string, and this single determined codeword string is recorded on the original CD 10 (FIGS. 9 and 10) serving as a recording medium according to the present invention. Alternatively, when the above-described modulation device 50 (FIGS. 16 and 17) is used, the minimum run length 3T to the maximum run length 12T are allowed, and the next code word from one code word is allowed. The combination bit 1b that gives the best DSV value in the codeword sequence is added to generate one decision codeword sequence, and this one decision codeword sequence is used as the original CD 10 (which is a recording medium according to the present invention). 9 and 10).

  Therefore, the specific data that cannot be discriminated in the sense of hearing when the above-described determination code word string is obtained, as shown in FIG. It is inserted in the section of index number 00).

  As a result, the entire original CD 10 recorded by inserting specific data that cannot be discerned in the sense of audibility into a music section and a silent section formed between songs is copied to a CD-R (copy recording medium). In this case, the copied CD-R also records specific data in the music information song section and in the silent section formed between the songs, as described above. When a -R is reproduced, an unreadable section occurs due to the copied specific data and the CD-R cannot be reproduced. Therefore, copyright infringement on the digital information signal on the copied CD-R is prevented in advance. Can do. At this time, the above-mentioned specific data can be inserted into the silent section (section with index number 00) without any correction.

  At this time, with a commercially available optical disk drive (for example, a CD player) that does not have a copy function, the original CD 10 (FIGS. 9 and 10) in which a large number of decision codeword strings are recorded can be normally reproduced without causing any trouble. .

It is a figure for demonstrating the signal format of the music information currently recorded on CD, (a) shows the original music data, (b) is the figure which showed the EFM signal. It is the figure which showed the encoding table at the time of 8-14 modulation. (A), (b) is a figure for demonstrating DSV control at the time of 8-14 modulation. It is a figure for demonstrating the subcode in the EFM signal shown in FIG.1 (b), (a) shows the subcode data before a modulation | alteration, (b) shows the frame structure of Q channel in subcode data. FIG. It is the figure which showed the state which comprised 1 block with 98 EFM signals shown in FIG.1 (b). It is the block diagram typically shown in order to demonstrate the conventional modulation apparatus. (A) to (c) are codeword sequences in which a combined bit is added between one codeword and the next codeword following the predetermined run length restriction rule using a conventional modulator. When (000), (001), and (010) are provisionally added as combined bits, the DSV values of a plurality of sets of codeword strings are calculated. FIG. 10 is a longitudinal sectional view showing an optical disc with copy prevention measures taken as an example of a conventional example. (A), (b) is the perspective view and longitudinal cross-section for demonstrating the optical disk used as the recording medium of a present Example which concerns on this invention. It is a figure for demonstrating a multi-session structure in the recording medium (optical disk) produced by applying the modulation apparatus and modulation method which concern on this invention. In the modulation apparatus and modulation method which concern on this invention, it is the block diagram (the 1) which showed typically the modulation apparatus to which Embodiment A is applied. FIG. 6 is a block diagram (part 2) schematically showing a modulation device to which the embodiment A is applied in the modulation device and the modulation method according to the present invention. (A)-(c) is between a codeword and the next codeword following it, strictly complying with the run-length restriction rule in the CD standard using the modulation device and modulation method to which the embodiment A is applied. When a codeword string is generated by adding a combination bit to the codeword, the next codeword following the one codeword and the next next codeword are pre-read, and one codeword and the next codeword are A pair of combined bits (000) is temporarily added between them, and three sets of combined bits (000), (001), and (010) are temporarily added between the next codeword and the next codeword. It is a figure for demonstrating the state which calculated each DSV value of many sets of codeword strings when it did. (A)-(c) is between a codeword and the next codeword following it, strictly complying with the run-length restriction rule in the CD standard using the modulation device and modulation method to which the embodiment A is applied. When a codeword string is generated by adding a combination bit to the codeword, the next codeword following the one codeword and the next next codeword are pre-read, and one codeword and the next codeword are A pair of combined bits (001) is temporarily added between them, and three sets of combined bits (000), (001), and (010) are temporarily added between the next codeword and the next codeword. It is a figure for demonstrating the state which calculated each DSV value of many sets of codeword strings when it did. (A)-(c) is between a codeword and the next codeword following it, strictly complying with the run-length restriction rule in the CD standard using the modulation device and modulation method to which the embodiment A is applied. When a codeword string is generated by adding a combination bit to the codeword, the next codeword following the one codeword and the next next codeword are pre-read, and one codeword and the next codeword are A pair of combined bits (010) is temporarily added between them, and three sets of combined bits (000), (001), and (010) are temporarily added between the next codeword and the next codeword. It is a figure for demonstrating the state which calculated each DSV value of many sets of codeword strings when it did. In the modulation apparatus and modulation method which concern on this invention, it is the block diagram (the 1) which showed typically the modulation apparatus to which Embodiment B is applied. FIG. 6 is a block diagram (part 2) schematically showing a modulation device to which the embodiment B is applied in the modulation device and the modulation method according to the present invention. (A), (b) is a figure for demonstrating the case where it encodes by accept | permitting the maximum run length which does not satisfy the run length restriction rule in CD standard using the modulation apparatus and the modulation method to which Embodiment B is applied. It is. It is the figure which showed the difference of the frequency spectrum accompanying the DSV value fluctuation | variation of a codeword sequence by the case of the original CD of the present Example which concerns on this invention, and the case of CD-R which copied the original CD. It is a schematic diagram for demonstrating the silence area between the music in a general CD. Schematic for explaining the case of the specific data insertion form in which the specific data that cannot be discriminated in the sense of hearing is inserted into the music section of the music information and the silent section formed between the songs in the recording medium according to the present invention. FIG.

Explanation of symbols

1 ... EFM signal,
1a... Frame synchronization signal, 1b... Combined bit, 1c.
1d: first code word string, 1e: C2 error correction code,
1f ... second codeword string, 1g ... C1 error correction code,
10: an optical disc as a recording medium of the present embodiment according to the present invention,
10a ... 1st session, 10a1 ... 1st lead-in area,
10a2 ... PCM audio data area, 10a3 ... first lead-out area, 10b ... second session, 10b1 ... second lead-in area,
10b2 ... compressed audio data area, 10b3 ... second lead-out area,
11 ... Transparent disk substrate, 12 ... Recording track, 13 ... Metal reflective film,
14 ... Protective film,
20 ... Conventional modulator,
21 ... Frame synchronization signal generator, 22 ... Subcode encoder,
23 ... CIRC encoder, 24 ... 8-14 modulation circuit,
25 ... Combined bit addition circuit, 26 ... DSV value calculation circuit,
27... DSV value comparison circuit / combined bit selection circuit,
30. Modulator according to the present invention (when embodiment A is applied),
31 ... Frame synchronization signal generator, 32 ... Subcode encoder,
33 ... ROM formatter, 34 ... switch,
35 ... CIRC encoder, 36 ... 8-14 modulation circuit,
37A: first combined bit adding circuit, 37B: second combined bit adding circuit,
38A ... 1st DSV value calculation circuit, 38B ... 2nd DSV value calculation circuit,
39: DSV value comparison circuit / combined bit selection circuit,
40: Determination code word string output circuit,
50. Modulator according to the present invention (when embodiment B is applied),
51 ... Frame synchronization signal generator, 52 ... Subcode encoder,
53 ... ROM formatter, 54 ... switch,
55 ... CIRC encoder, 56 ... 8-14 modulation circuit,
57 ... Combined bit addition circuit, 58 ... DSV value calculation circuit,
59... DSV value comparison circuit / combined bit selection circuit,
AD ... Original music data
CAD: compressed audio data, PCMAD: PCM audio data,
D: Input code word, Cx, Cy, Cz: Code word.

Claims (5)

A p-bit input data word is converted into a q-bit code word, and an r-bit combined bit is added between adjacent code words to generate a code word string, and this code word string is recorded on a recording medium. In a modulation device for
Copy prevention adding means for adding a copy prevention effect using TOC information recorded in the lead-in area of the recording medium;
modulation means for prefetching at least the next code word following one code word and the next next code word when converting the p-bit input data word into the q-bit code word;
A plurality of sets of coupled bits of r bits between the one codeword and the next codeword are tentatively added while strictly complying with a predetermined run length restriction rule to generate a plurality of sets of codeword strings; In addition, a plurality of sets of combined bits of r bits are strictly adhered to a predetermined run length restriction rule between the next code word in the plurality of code word strings and at least the next next code word. A combined bit adding means for generating a plurality of sets of codeword strings from at least the one codeword to the next codeword,
DSV value calculating means for calculating each DSV value of a large number of codeword strings generated by the combined bit adding means;
Comparison / selection means for selecting one set of code word strings whose absolute value of DSV value is closest to zero among the DSV values of a large number of code word strings obtained by the DSV value calculation means. When,
Using the combined bits added between the one codeword and the next codeword in the one set of codeword strings selected by the comparison / selection means, the combined bits from the one codeword A decision codeword string output means for outputting one decision codeword string finally determined by combining up to the next codeword via
When the input data word is music information and the determined code word string is encoded by adding the music information and specific data that cannot be discerned in the sense of hearing, the specific data is a song section of the music information. A modulation device, wherein the modulation device is inserted in a silent section formed between and between songs. A p-bit input data word is converted into a q-bit code word, and an r-bit combined bit is added between adjacent code words to generate a code word string, and this code word string is recorded on a recording medium. In a modulation device for
Copy prevention adding means for adding a copy prevention effect using TOC information recorded in the lead-in area of the recording medium;
modulation means for prefetching at least the next codeword following one codeword when converting the p-bit input data word to the q-bit codeword;
A combination that generates a plurality of sets of codeword strings by temporarily adding a plurality of sets of combined bits of r bits between the one codeword and the next codeword without strictly observing a predetermined run length restriction rule. Bit addition means;
DSV value calculating means for calculating each DSV value of the plurality of sets of codeword strings generated by the combined bit adding means;
Among the DSV values of the plurality of sets of codeword sequences obtained by the DSV value calculation means, one set of the codeword sequences whose absolute value of the DSV value is closest to zero is selected. Comparing / selecting means for outputting one set of the code word strings as a determined code word string,
When the input data word is music information and the determined code word string is encoded by adding the music information and specific data that cannot be discerned in the sense of hearing, the specific data is a song section of the music information. A modulation device, wherein the modulation device is inserted in a silent section formed between and between songs. A p-bit input data word is converted into a q-bit code word, and an r-bit combined bit is added between adjacent code words to generate a code word string, and this code word string is recorded on a recording medium. Modulation method for
A copy prevention adding step of adding a copy prevention effect using TOC information recorded in the lead-in area of the recording medium;
a modulation step of prefetching at least the next codeword following one codeword and the next next codeword when converting the p-bit input data word into the q-bit codeword;
A plurality of sets of coupled bits of r bits between the one codeword and the next codeword are tentatively added while strictly complying with a predetermined run length restriction rule to generate a plurality of sets of codeword strings; In addition, a plurality of sets of combined bits of r bits are strictly adhered to a predetermined run length restriction rule between the next code word in the plurality of code word strings and at least the next next code word. A combined bit adding step for generating a plurality of sets of code word strings from at least one code word to the next next code word,
A DSV value calculating step of calculating each DSV value of the multiple codeword strings generated in the combined bit adding step;
Comparison / selection step of selecting one set of the code word strings in which the absolute value of the DSV value is closest to zero among the DSV values of the plurality of sets of code word strings obtained in the DSV value calculating step When,
Using the combined bits added between the one codeword and the next codeword in the one set of codeword strings selected in the comparison / selection step, the combined bits from the one codeword A decision codeword sequence output step for outputting one decision codeword sequence finally determined by combining up to the next codeword via
When the input data word is music information and the determined code word string is encoded by adding the music information and specific data that cannot be discerned in the sense of hearing, the specific data is a song section of the music information. A modulation method, wherein the modulation method is inserted into a silent section formed between and between songs. A p-bit input data word is converted into a q-bit code word, and an r-bit combined bit is added between adjacent code words to generate a code word string, and this code word string is recorded on a recording medium. Modulation method for
A copy prevention adding step of adding a copy prevention effect using TOC information recorded in the lead-in area of the recording medium;
a modulation step of prefetching at least the next codeword following one codeword when converting the p-bit input data word into the q-bit codeword;
A combination that generates a plurality of sets of codeword strings by temporarily adding a plurality of sets of combined bits of r bits between the one codeword and the next codeword without strictly observing a predetermined run length restriction rule. A bit addition step;
A DSV value calculating step of calculating each DSV value of the plurality of sets of codeword strings generated in the combined bit adding step;
Among the DSV values of the plurality of sets of codeword sequences obtained in the DSV value calculation step, one set of the codeword sequences whose absolute value of the DSV value is closest to zero is selected. A comparison / selection step of outputting two sets of the code word strings as a decision code word string,
When the input data word is music information and the determined code word string is encoded by adding the music information and specific data that cannot be discerned in the sense of hearing, the specific data is a song section of the music information. A modulation method, wherein the modulation method is inserted into a silent section formed between and between songs. A recording medium on which the determined codeword string encoded by any of the modulation device according to claim 1 or 2, or the modulation method according to claim 3 or 4 is recorded.

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