JP2004220733A - Modulating device, modulation method, recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent copying of a digital information signal on an original CD. <P>SOLUTION: Copy preventing effect is added using TOC information recorded in a lead-in region of an original CD1. A code word Cy succeeding one code word Cx and a code word Cz succeeding the code word Cy are previously read at least, and a plurality of groups of coupling bits 1b of r bits are added temporarily between one code word Cx and the code word Cy and between the code word Cy and the code word Cz without strictly observing a run-length limit rule. Many groups of code word trains from one code word Cx to the code word Cz are generated, one group of code word train of which the absolute value of DSV value is the nearest to zero out of the DSV values of many groups of code word trains is selected, and the coupling bit added between one code word Cx in this one group of code word train and the code word Cy is used. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a modulation device, a modulation method, and a recording medium for preventing a digital information signal recorded on a recording medium such as an optical disk from being copied.
[0002]
[Prior art]
With the advent of the digital multimedia age, large-capacity digital information signals have been recorded on recording media such as optical disks.
[0003]
For example, an optical disc such as a CD (Compact Disc) containing music information or a CD-ROM (CD-Read Only Memory) containing computer data is used to convert a digital information signal into concave pits on a disc-shaped transparent disc substrate. It is formed into a read-only type by converting it into a pit row with convex lands and engraving this pit row as a spiral or concentric track on a transparent disk substrate, and accessing a desired track at high speed during reproduction. It is widely used because it is suitable for mass production and can be obtained at low cost.
[0004]
By the way, music information recorded on CDs and computer data recorded on CD-ROMs are protected by copyright law, but since they are digital information, there is no signal deterioration. The user can copy to a write-once optical disc such as a CD-R (Compact Disc-Recordable) that can be written only once without permission of the copyright holder, or a CD-RW (Compact Disc-ReWritable) that can be written multiple times. It is possible to do.
[0005]
The write-once optical discs such as the CD-R and CD-RW described above have substantially the same external appearance as read-only optical discs such as CDs and CD-ROMs, but have spiral grooves formed on a transparent disc substrate. Alternatively, the recording layer is formed concentrically, an organic dye serving as a recording layer is spin-coated on the concave groove side, and a reflective film and a protective film are sequentially formed on the organic dye. Moreover, it is available at low cost.
[0006]
Then, when music information recorded on a CD or computer data recorded on a CD-ROM is copied to a CD-R or CD-RW, it is recorded in the same signal format as the CD or CD-ROM. This infringes copyright.
[0007]
Note that the present invention is particularly directed to a case where music information is recorded on a recording medium, and therefore, a code word string of music information recorded on a CD will be described below.
[0008]
FIGS. 1A and 1B are diagrams for explaining a signal format of music information recorded on a CD. FIG. 1A shows original music data, FIG. 1B shows an EFM signal, and FIG. A diagram showing an encoding table at the time of modulation,
FIGS. 3A and 3B are diagrams for explaining DSV control at the time of 8-14 modulation,
FIG. 4 is a diagram for explaining the subcode in the EFM signal shown in FIG. 1 (b), (a) shows the subcode data before modulation, and (b) shows the Q channel of the subcode data. Diagram showing the frame structure,
FIG. 5 is a diagram showing a state in which 98 EFM signals shown in FIG. 1B constitute one block.
[0009]
First, music information is recorded on a CD in a signal format conforming to the CD standard book “Red Book” or the IEC (International Electrotechnical Commission) 908 standard.
[0010]
At this time, in general, the pit length recorded on the CD is limited to the minimum run length (minimum pit length or minimum land length) due to the optical transmission characteristics of recording and 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 must have a low-frequency component and a DC component suppression characteristic of the recording signal. It needs to be modulated.
[0011]
Among the modulation schemes satisfying this restriction, the EFM (Eighth Fourteen Modulation: 8-14 modulation) scheme used for CDs has a minimum run length of 3T (T = cycle of channel bits) and a maximum run length of 11T. Things.
[0012]
That is, as shown in FIG. 1A, the music original data AD to be recorded on the CD is digital data, and upper 8 bits (1 byte) + lower 8 bits (1 byte) = 16 bits (2 bytes) and 1 bit. A unit is constituted, and the music original data AD is constituted by a plurality of these one units.
[0013]
When the original music data AD shown in FIG. 1A is recorded on a glass master by a laser beam at the time of mastering, the original music data AD is converted into an EFM signal format so as to have a signal form suitable for recording. Then, it is recorded on the glass master in the form of the EFM signal 1 shown in FIG. 1 (b), and thereafter, a metal master board, a mother board, and a stamper board are sequentially manufactured by electroforming based on the glass master. Thereafter, the stamper board is mounted in the injection molding machine, and the signal surface of the stamper board is transferred to the transparent disk substrate to produce a CD. Therefore, the signal surface of the CD is equivalent to the signal surface of the glass master disc.
[0014]
Here, in the format of the EFM signal 1 described above, the input music original data AD is divided into an upper 8-bit input data word D and a lower 8-bit input data word D, and the encoding table shown in FIG. Referring to the input data word D of p bits = 8 bits, a run length limited code of q bits = 14 bits (hereinafter referred to as “q bits = 14 bits”) satisfying a predetermined run length restriction rule that the minimum run length is 3T and the maximum run length is 11T. , Codeword C), and as shown in FIG. 1 (b), between the converted codeword C and the codeword C, for holding the run-length restriction rule and DSV (Digital Sum Value). The first and second code word strings 1d and 1f to be described later are generated as an EFM signal 1 by adding r bits = 3 combination bits 1b for control. To have.
[0015]
At this time, when a predetermined run length restriction rule is satisfied, the minimum run length is 3T, and the number of “0” s between the logical values “1” and “1” in the code word C is at least d = 2. On the other hand, when the maximum run length is 11T, at most k = 10 “0” s are included between logical values “1” and “1” in the code word C. In other words, when the run length restriction rule RLL (d, k) = RLL (2,10) is satisfied, the minimum run length is determined based on the run length restriction rule RLL (d, k) = RLL (2,10). (D + 1) T = 3T, and the maximum run length is set to (k + 1) T = 11T. The first and second codeword strings 1d and 1f, which are obtained by adding a 3-bit combination bit 1b between adjacent codewords C and C, have a minimum run length (d + 1) T = 3T to a maximum run length ( k + 1) T = 11T, and when the NRZI conversion is performed on the first and second codeword strings 1d and 1f as described later, the minimum run length 3T is the minimum inversion interval, while the maximum The run length 11T indicates the maximum inversion interval.
[0016]
The pfm modulation = 8-14 modulated EFM signal 1 satisfies the run length restriction rule RLL (d, k) = RLL (2,10) in which the minimum run length is 3T and the maximum run length is 11T. However, the DC component and the low frequency component of the EFM signal 1 can be reduced.
[0017]
Further, NRZI (Non Return to Zero Inverted) conversion is performed on the EFM signal 1 including the first and second codeword strings 1d and 1f. As is well known, the NRZI conversion has a polarity at bit "1". Since the modulation is performed without inverting the polarity at bit “0”, the waveform after the NRZI conversion becomes the recording signal R on the glass master, and the L (low) level section of the recording signal R is For example, a pit row is formed so as to correspond to a concave pit (or a convex land), and the H (high) level section in the recording signal R corresponds to, for example, a convex land (or a concave pit).
[0018]
As shown in FIGS. 3A and 3B, the above-mentioned DSV has a waveform of H (high) level after the NRZI conversion from the start time of the codeword string in the EFM signal 1 to the present time. This is an integrated value obtained by integrating “1” (positive polarity) at time and “−1” (negative polarity) at L (low) level. At this time, in the NRZI conversion, since the polarity inversion is performed at the data bit “1”, even if the code word has the same bit pattern, it differs depending on the waveform state after the NRZI conversion immediately before connecting the code word. As shown in FIG. 3A, when the waveform state immediately before the input data word = 002 is at the L (low) level, and as shown in FIG. The DSV value is inverted when the waveform state is at the H (high) level. For example, when the input data word = 002 and the input data word = 253 are connected via a connection bit, FIG. The absolute value of both DSVs in FIG. 3B is the same.
[0019]
Here, as a combination of three bits between adjacent codewords C and C such that the absolute value of DSV approaches zero while satisfying the run-length restriction rule RLL (d, k) = RLL (2,10), By selecting and adding one of the sets (000), (001), (010), and (100), the DC component of the waveform of the recording signal R is reduced, and as a result, the recording signal When the R waveform is viewed over a long period, the H (high) level section and the L (low) level section appear at substantially the same ratio, so that the concave pit section and the convex land section also appear at substantially the same rate. The DSV value is controlled as described above.
[0020]
Referring back to FIG. 1B, one frame of the EFM signal 1 includes a frame synchronization signal 1a, a combination bit 1b, a subcode 1c, a combination bit 1b, a first code word sequence 1d, a combination bit 1b, and a C2 error from the beginning. The correction code 1e, the combination bit 1b, the second code word string 1f, the combination bit 1b, the C1 error correction code 1g, and the combination bit 1b are arranged in this order, and are composed of 588 channel bits in total for one frame. .
[0021]
Here, the frame synchronization signal 1a arranged at the beginning can be identified with respect to each of the signals 1b to 1g as 11T, 11T, and 2T signals to indicate the beginning of the frame using 24 bits. .
[0022]
The sub-code 1c arranged after the frame synchronization signal 1a via the 3-bit combination bit 1b is a signal for controlling reproduction to a CD. As shown in FIG. 4A, the sub-code data SD before modulation corresponding to the sub-code 1c is composed of 98 frames consisting of 8 bits b1 to b8, and the first two frames are common to each channel. , And eight channels P, Q, and R to W are allocated to the remaining 96 frames. At this time, the P channel is a simple playback control, that is, a cue signal of each music piece. Further, the Q channel indicates the content type of 4 bits of control for indicating audio data, computer data, etc., and 72 bits of subsequent data, as shown in FIG. 4B, in order to perform finer reproduction control. Address, 4 bits of data for indicating the recording start time, and 16 bits of CRC (Cyclic Redundancy Code) for detecting cyclic code errors. Further, the six channel bits of R to W are used for special purposes such as displaying still images and karaoke characters.
[0023]
Returning to FIG. 1B again, the first code word string 1d arranged via the 3-bit combination bit 1b after the subcode 1c is obtained by converting each input data word D (each music original data) of p = 8 bits. Referring to the encoding table shown in FIG. 2, the codewords are converted into q = 14 bits of each codeword C, and the three combined bits 1b are added between adjacent codewords C, C, so that 12 , And 11 combined bits 1b.
[0024]
Further, the C2 error correction code 1e arranged after the first code word string 1d via the 3-bit combination bit 1b is converted into the first code word string 1d and the second code word string 1f of the EFM signal 1 during CD reproduction. The error correction is performed for this.
[0025]
Further, the second code word sequence 1f arranged via the 3-bit combination bit 1b after the C2 error correction code 1e has 12 code words C (12 symbols) like the first code word sequence 1d described above. And 11 combined bits 1b.
[0026]
Further, the C1 error correction code 1g arranged after the second codeword string 1f via the 3-bit combination bit 1b is used to output the first codeword string 1d, the second codeword string 1f, and C2 of the EFM signal 1 during CD reproduction. Error correction is performed on the error correction code 1e.
[0027]
Then, as shown in FIG. 5, 98 (= 98 frames) continuous recording signals after NRZI conversion for one frame of the above-described EFM signal 1 constitute one block. A block corresponds to a period of 1/75 second.
[0028]
Here, a conventional modulation device will be described with reference to FIGS.
[0029]
FIG. 6 is a block diagram schematically showing a conventional modulation device,
FIGS. 7 (a) to 7 (c) show a code obtained by adding a connection bit between one code word and the next code word while strictly observing a predetermined run-length restriction rule using a conventional modulator. A description will be given of a state where DSV values of a plurality of sets of code word strings are calculated when (000), (001), (010), and (100) are temporarily added as connection bits when a word string is generated. FIG.
[0030]
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 (not shown) for copying music information recorded on a CD to a CD-R. (Not shown), a frame synchronization signal generator 21, a subcode encoder 22, a CIRC encoder 23, an 8-14 modulation circuit 24, a combined bit addition circuit 25, and a DSV value. It is roughly composed of an arithmetic circuit 26 and a DSV value comparison circuit / combined bit selection circuit 27.
[0031]
More specifically, in the conventional modulation device 20, a frame synchronization signal generator 21 for generating the 22-bit frame synchronization signal 1a described above with reference to FIG. 1B is separately provided. 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).
[0032]
Further, the sub-code data SD before modulation corresponding to the sub-code 1c described above with reference to FIG. 1B is converted by the sub-code encoder 22 into a predetermined format shown in FIGS. 4A and 4B. It is generated into 8 bits and input to the 8-14 modulation circuit 24.
[0033]
Also, the 16-bit music original data AD is separated into an upper 8-bit input data word D and a lower 8-bit input data word D as described above with reference to FIG. 1A, and the CIRC (Cross Interleave Reed) is separated. -Solomon Code) is input to the encoder 23 in chronological order, where error correction code processing is performed by combining two systems of 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.
[0034]
Next, in the 8-14 modulation circuit 24, the inputted 8-bit subcode data SD is converted into a 14-bit subcode 1c based on the encoding table shown in FIG. Is added after the frame synchronization signal 1a of the EFM signal 1 (FIG. 1).
[0035]
Further, in the 8-14 modulation circuit 24, when sequentially converting the 8-bit input data word D into the 14-bit code word C based on the encoding table shown in FIG. The next code word Cy following one code word Cx is sequentially read. Then, one codeword Cx and the next codeword Cy are input from the 8-14 modulation circuit 24 to the combination bit addition circuit 25.
[0036]
Next, the combination bit addition 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 codewords C, C A function of adding a 3-bit combination bit 1b is provided between them. This combination-bit addition circuit 25 includes (000), (001), (010), and (100) as candidates for the 3-bit combination bit 1b. ) Are prepared. Note that, although there are eight 3-bit combination bits 1b, in the sets (011), (101), (110), and (111) other than the four sets described above, two or more "1" s appear continuously. Alternatively, it cannot be used because “1” and “0” appear alternately and do not satisfy the run-length restriction rule RLL (2, 10).
[0037]
Then, in order to combine the codeword Cx and the codeword Cy sequentially input into the combination bit addition circuit 25, four sets of combination bits (000), (001), and (010) are provided between the codewords Cx and Cy. , (100) are temporarily added to generate a plurality of sets of codeword strings.
[0038]
At this time, as shown in FIG. 7, for example, one code word Cx is “010” in the 12th to 14th bits, while the next code word Cy is “00100010000010”. The 13th bit of one codeword Cx is “1”, and the third bit of the next codeword Cy is “1”. Although the three sets of combination bits (000), (001), and (010) can strictly adhere to the run-length restriction rule RLL (2, 10), the fourth set of combination bits (100) has the run-length restriction rule RLL (2, 10). Since the condition (10) is not satisfied, the addition of the combined bit (100) is stopped.
[0039]
Then, after adding three sets of connection bits (000), (001), and (010) between the codewords Cx and Cy, the three sets of codeword strings {Cx (000) Cy} and {Cx (001) Cy are obtained. {Cx (010) Cy} is input to the DSV value calculation circuit 26 to calculate each DSV value of the three sets of codeword strings. As a result, as shown in Case 1 of FIG. When a combination bit (000) is added between Cy, the DSV value of the codeword string {Cx (000) Cy} becomes +2, and as shown in Case 2 shown in FIG. When the combination bit (001) is added to the code word string {Cx (001) Cy}, the DSV value becomes -4, and between the code words Cx and Cy as in Case 3 shown in FIG. When the combination bit (010) is added, the code word sequence {Cx (010) Cy} SV value is -6.
[0040]
Thereafter, the three sets of codeword strings from the DSV value calculation circuit 26 and the respective DSV values corresponding thereto are input to a DSV value comparison circuit / combination bit selection circuit 27, and this DSV value comparison circuit / combination bit selection circuit 27 And selecting one set of codeword strings {Cx (000) Cy} having a DSV value = + 2 such that the absolute value of the DSV is closest to zero among the DSV values of the three sets of codeword strings. This one set of code word strings {Cx (000) Cy} is output from the DSV value comparison circuit / combination bit selection circuit 27 as one determined code word string. In other words, the DSV value comparison circuit / combined bit selection circuit 27 selects the combined bit (000) corresponding to one decision code word string {Cx (000) Cy} whose DSV absolute value is closest to zero. become. Hereinafter, the above procedure is repeated following the next code word Cy to obtain one determined code word string {Cx (000) Cy...}.
[0041]
Thereafter, one decision code word string {Cx (000) Cy...} Whose DSV value is controlled is generated as a recording signal R (FIG. 1) suitable for recording, and the laser beam is used to produce a CD glass master. Alternatively, it is recorded on a CD-R.
[0042]
Then, a stamper disk (not shown) is manufactured based on the glass master disk for the CD, and a CD is manufactured using the stamper disk.
[0043]
From the above, the user uses the CD-ROM drive (not shown) in the personal computer to insert a CD containing music information to be copied according to copy software stored in a hard disk (not shown) in a personal computer (not shown). Playback, music information output from the CD-ROM drive and desired to be recorded on the CD-R is input to a CD-R drive (not shown), and copied by a conventional modulation device 20 provided in the CD-R drive. It is possible to copy desired music information to a CD-R without obtaining the permission of the copyright holder.
[0044]
Therefore, when the 16-bit music original data AD output from the CD-ROM drive is encoded by the conventional modulation device 20 provided in the CD-R drive, the music information recorded on the CD-R is recorded on the CD. Since the EFM signal form is exactly the same as the recorded music information, the copied CD-R can be further copied, so that a large amount of the CD-R is circulated in the world.
[0045]
Therefore, as described above, there is an example of an optical disc that can prevent copying of music information recorded on a CD or computer data recorded on a CD-ROM to a recordable / reproducible CD-R or CD-RW. (For example, see Patent Document 1).
[0046]
[Patent Document 1]
JP-A-2001-357536 (pages 4-5, FIG. 4)
FIG. 8 is a longitudinal sectional view showing an optical disk on which a copy protection measure is taken as an example of a conventional example.
[0047]
The conventional optical disc 100 shown in FIG. 8 is disclosed in the above-mentioned Patent Document 1 (Japanese Patent Application Laid-Open No. 2001-357536), and when briefly described with reference to Patent Document 1, a CD-ROM, In the conventional optical disc 100 in which a copy protection measure is applied to an optical disc such as a DVD-ROM, usually, based on a run length restriction rule (described in the same publication as a run length suppression type coding system). Although a row of concavo-convex portions 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 is formed in the middle of this. The projection is recorded.
[0048]
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 the pits A and B are values that are not based on the run length restriction rule.
[0049]
Therefore, in the conventional optical disc 100, among the run length restriction rules based on the minimum run length 3T and the maximum run length 14T, the minimum run length 3T is not strictly adhered to but is set to a smaller value 1T to 2T. Thus, the minimum pit length (or minimum land length) on the optical disc 100 is formed smaller than usual.
[0050]
[Problems to be solved by the invention]
Therefore, based on the above-described technical idea of the conventional optical disc 100, an uneven portion row (pit row) having a continuous length of 3T to 11T is formed based on the run length restriction rule RLL (2, 10) in the CD standard. In order to modify a part of the signal form of the CD by applying to the well-known CD, for example, in the encoding table shown in FIG. 2, the code word C for the input data word D = 255 is “00100000010010”. However, when it is desired to form a short uneven portion row (pit row) such as 1T, a modified CD can be manufactured by using a code word C such as “00100110010010” instead.
[0051]
When the CD modified in this way is reproduced by a commercially available CD player (not shown), the certification pit having a short continuous length of 1T to 2T in the data has a normal pit length of 3T to 11T (land). Long), the RF signal read using the optical pickup does not reach a sufficient light level or a sufficient dark level, and a binary signal obtained from the RF signal has a 1T to 2T signal. Since the certification pit signal is not included, it cannot be determined whether or not the optical disc being reproduced is the original.
[0052]
Further, when music data recorded on a modified CD is reproduced by a CD-ROM drive in a personal computer (not shown) and the reproduced data is input to a CD-R drive and copied to a CD-R, a problem occurs. And the music data is copied.
[0053]
Therefore, the copy prevention means based on the premise of the spread of a new player capable of detecting the proof pit like the optical disk 100 is used in a situation where a large number of players and CD-R drives are already on the market such as a CD. There is a problem that it cannot be applied.
[0054]
Further, 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), copy control CD (Copy Control CD: Although the practical use of CCCD has begun, 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.
[0055]
Therefore, when a code word string is generated while providing the above-mentioned technical idea of the CCCD and allowing the minimum run length 3T to the maximum run length 12T without strictly observing a predetermined run length restriction rule, this code word is generated. While the original CD in which the rows are recorded can be reliably reproduced by a commercially available CD player (not shown), a copy recording medium on which the original CD is copied has a reproduction failure, so that a personal computer (not shown) can be used. There is a demand for a modulation device, a modulation method, and a recording medium that can reliably prevent copying of a digital information signal recorded on an original CD even when the CCCD does not function effectively in the CD-ROM drive described in (1).
[0056]
[Means for Solving the Problems]
The present invention has been made in view of the above problems, and a first invention is to convert an input data word of p bits into a code word of q bits, and to convert r bit combination bits between adjacent code words. In addition, a modulation device for generating a code word string by adding the code word string to a recording medium,
Copy protection adding means for adding a copy protection effect using TOC information recorded in the lead-in area of the recording medium;
when converting the p-bit input data word into the q-bit code word, a next code word that follows one code word, and a modulation unit that at least pre-reads the next next code word;
Between the one codeword and the next codeword, a plurality of sets of combined bits by the r bits are temporarily added without strictly observing a predetermined run-length restriction rule to generate a plurality of sets of codeword strings, Further, even between the next code word in the plurality of code word strings and at least the next next code word, the plurality of combined bits by the r bits are not strictly adhered to a predetermined run-length restriction rule. Temporary bit addition means for generating a large number of sets of codeword strings from at least one codeword to the next codeword,
DSV value calculation means for calculating each DSV value of a large number of sets of the code word strings generated by the combination bit addition means;
Comparing / selecting means for selecting one set of the codeword strings whose absolute value of the DSV value is closest to zero among the DSV values of the multiple sets of the codeword strings obtained by the DSV value calculating means; When,
Using the combination bits added between the one codeword and the next codeword in the one set of codeword strings selected by the comparison / selection means, And a decision code word string output unit that outputs one decision code word string that is finally determined by combining up to the next code word through
A code word string output in strict observance of the run-length restriction rule inputs specific data that includes a specific frequency component, as the input data word over a predetermined period, and the period is A modulation device for outputting a codeword string without strictly observing a run-length restriction rule.
[0057]
According to a second aspect, in the modulation device according to the first aspect,
The modulation device is characterized in that the specific data is AC signal data or DC signal data that cannot be discriminated in terms of hearing.
[0058]
According to a third invention, in the modulation device according to the first or second invention,
When the input data word is music information, and the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is inserted in a silent section formed between songs. A modulation device characterized in that:
[0059]
According to a fourth aspect, in the modulation device according to the first or second aspect described above,
When the input data word is music information, and when the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is included in a silent section formed between songs. In addition, the modulation device is inserted in a section excluding the section of index number 00.
[0060]
According to a fifth aspect of the present invention, a p-bit input data word is converted into a q-bit code word, and r-bit combination bits are added between adjacent code words to generate a code word sequence. In a modulation method for recording a word string on a recording medium,
A copy protection adding step of adding a copy protection effect using the TOC information recorded in the lead-in area of the recording medium;
when converting the p-bit input data word into the q-bit code word, a modulation step of at least pre-reading a next code word following one code word and a next next code word;
Generating a plurality of sets of codeword strings by temporarily adding a plurality of sets of combination bits by the r bits between the one codeword and the next codeword without strictly observing a predetermined run-length restriction rule; Further, even between the next codeword in the plurality of codeword strings and at least the next next codeword, a plurality of sets of combination bits by the r bits are not strictly adhered to a predetermined run-length restriction rule. A combined bit adding step of generating a large number of sets of codeword strings from at least one codeword to the next next codeword;
A DSV value calculating step of calculating each DSV value of the multiple sets of the code word strings generated in the combining bit adding step;
A comparing / selecting step of selecting one set of the codeword strings whose absolute value of the DSV value is closest to zero among the DSV values of the multiple sets of the codeword strings obtained in the DSV value calculating step; When,
Using a combination bit added between the one codeword and the next codeword in the one set of codeword strings selected in the comparison / selection step, the combination bits from the one codeword are used. A decision code word sequence output step of outputting one decision code word sequence finally determined by combining up to the next code word through
A code word string output in strict observance of the run-length restriction rule inputs specific data that includes a specific frequency component, as the input data word over a predetermined period, and the period is This is a modulation method for outputting a codeword string without strictly observing a run-length restriction rule.
[0061]
According to a sixth aspect, in the modulation method according to the fifth aspect,
The modulation method is characterized in that the specific data is AC signal data or DC signal data that cannot be discriminated in terms of hearing.
[0062]
According to a seventh aspect, in the modulation method according to the fifth or sixth aspect,
When the input data word is music information, and the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is inserted in a silent section formed between songs. The modulation method is characterized in that:
[0063]
According to an eighth invention, in the modulation method according to the fifth or sixth invention,
When the input data word is music information, and when the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is included in a silent section formed between songs. In addition, the modulation method is characterized by being inserted in a section excluding the section of index number 00.
[0064]
Further, a ninth invention is directed to a recording medium which records the codeword string encoded by any one of the modulation devices according to the first to fourth inventions or the modulation method according to the fifth to eighth inventions. It is.
[0065]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present embodiment of the modulation device, the modulation method, and the recording medium according to the present invention will be described in detail with reference to FIGS.
[0066]
In the modulation device, the modulation method, and the recording medium according to the present invention, for example, in the case of conforming to the CD standard, an input data word of p bits = 8 bits is converted into a code word C of q bits = 14 bits, and an adjacent data word is converted to a code word C of q bits = 14 bits. When an EFM signal 1 shown in FIG. 1B is generated by adding r bits = 3 combination bits 1b between matching codewords C, C, and this EFM signal 1 is recorded on a recording medium such as an optical disk. In addition, the technology of copy control CD (CCCD) is provided by adding a copy protection effect using TOC information recorded in the lead-in area of the optical disc (recording medium), and at the same time, the next And the next next code word at least, and the minimum run length set based on the run length restriction rule RLL (d, k) = RLL (2, 10) in the CD standard. Without strict adherence to d + 1) T = 3T to maximum run length (k + 1) T = 11T, instead of allowing minimum run length (d + 1) T = 3T to maximum run length (k + 2) T = 12T, A connection bit 1b between one codeword and the next codeword is selected and added while considering the DSV value of a codeword string from one codeword to the next codeword at least to the next codeword. Then, a code word string from one code word to the next code word is output as one finally determined code word string through the combination bit 1b, and a large number of the determined code word strings are generated in succession. The recorded EFM signal 1 is recorded on a recording medium such as an optical disk. When the original recording medium on which the EFM signal 1 is recorded is reproduced, the first and second EFM signals 1 of specific data described later are particularly used. The two-code word strings 1d and 1f can be reproduced without any trouble. On the other hand, when the copy recording medium copied through the copy control CD (CCCD) function of the original recording medium is reproduced, the copied specific data is not reproduced. The reproduction signals of the first and second code word strings 1d and 1f are characterized in that components of specific frequencies increase and the reproduction becomes impossible.
[0067]
By the way, especially in the original recording medium on which the first and second code word strings 1d and 1f composed of the specific data are recorded, since the conventional CD standard is satisfied, no data reading error occurs.
[0068]
<Example>
Before describing the modulation device and the modulation method according to the present invention, the structure of a recording medium manufactured by applying the modulation device and the modulation method will be described first.
[0069]
9A and 9B are a perspective view and a sectional view showing a recording medium (optical disk) manufactured by applying the modulation device and the modulation method according to the present invention.
FIG. 10 is a diagram for explaining a multi-session structure in a recording medium (optical disc) manufactured by applying the modulation device and the modulation method according to the present invention.
[0070]
As shown in FIGS. 9A and 9B, the recording medium 10 produced by applying the modulation device and the 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 hole diameter of a center hole of 15 mm, and a substrate thickness of 1.2 mm. 11a, a digital information signal is converted into a digital pit row by concave pits and convex lands, and this pit row is formed as a spiral or concentric recording track 12 on one surface 11a to form a signal surface. Is recorded. At this time, the digital information signal recorded on the recording track 12 is described later so that the minimum run length is 3T and the maximum run length is 12T by the EFM (Eight to Fourteen Modulation: 8-14 modulation) method. This is encoded using the modulation device of the present embodiment.
[0071]
Further, a metal reflective film 13 and a protective film 14 are sequentially formed on the signal surface of the original CD 10, so that the original CD 10 is formed as a read-only type. The surface 11b of the transparent disk substrate 11 opposite to the one surface 11a is the side on which the reproduction laser beam Lp is irradiated.
[0072]
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 including 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 peripheral area, and subsequently, a second session 10b is provided on the outer peripheral side.
[0073]
The first session 10a includes a first lead-in area 10a1 in which a table of contents, recording time, control information, and the like 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 A first lead-out area 10a3 in which the end information of the session 10a is recorded.
[0074]
On the other hand, the second session 10b includes a second lead-in area 10b1 in which a table of contents, recording time, control information, and the like 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 a second lead-out area 10a3 in which end information of the second session 10b is recorded.
[0075]
Here, in the present invention, the first TOC (Table of Contents) information recorded in the first lead-in area 10a1 of the first session 10a and the second TOC information recorded in the second lead-in area 10b1 of the second session 10b. By adding a copy protection effect using the above, the technical concept of the copy control CD (CCCD) described above is provided.
[0076]
More specifically, according to the frame structure of the Q channel in the subcode data SD described with reference to FIGS. 4A and 4B, the data is recorded in the first and second lead-in areas 10a1 and 10b1. In the first and second TOC information, if the recording track in each of the data areas 102a and 102b is an audio track, 4-bit 0000 indicates “0”, while if the recording track is a data track, the 4-bit 0100 indicates “0”. And CONTROL indicating "4", TNO indicating a song number from 01 to 99 (including the pointer B0 during the session), and START POSITION (MIN, SEC, FRAME) is recorded.
[0077]
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 based on the CD standard data (IEC 908 standard). Specifically, the CONTROL is set to “0” to indicate that the PCM audio data area 10a2 is an audio track, and the START POSITION is set in the normal order in the TNO (song number) in the first session 10a. MIN (minutes), SEC (seconds), and FRAME (frames) 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 Point for searching area 10b2 Data B0 is recorded.
[0078]
On the other hand, when recording the 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 does not comply with the CD standard (IEC908 standard) but does not comply with the CD standard. More specifically, for the part corresponding to the TNO (song number) included in the first session 10a, "4" is set in CONTROL to intentionally erroneously indicate that the data track is a data track. In addition to the recording, the MIN (minute), SEC (second), and FRAME (frame) that are intentionally set incorrectly in the START POSITION without corresponding to the position of the outer peripheral part in the order of TNO (tune number) in the second session 10b Are sequentially recorded.
[0079]
As described above, the first TOC information based on the CD standard data is recorded in the first lead-in area 10a1 of the first session 10a, and the second TOC information 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 copy software is activated in the personal computer and the original CD 10 is reproduced, the light in the CD-ROM drive is read. First, the pickup reads each data in the first TOC information recorded in the first lead-in area 10a1 on the inner circumference, and subsequently reads the second TOC information recorded in the second lead-in area 10b1 by the pointer B0 recorded in the first TOC information. Is read. Then, the CD-ROM drive causes a malfunction due to the rattling second TOC information recorded in the second lead-in area 10b1, and stops reproducing the PCM audio data recorded in the PCM audio data area 10a2 of the first session 10a. In this case, the original CD 10 cannot be copied to the CD-R using the CD-R drive, and the technical idea of the CCCD functions effectively.
[0080]
On the other hand, depending on the type of the CD-ROM drive in the personal computer, the technical idea of the CCCD does not work, that is, despite the fact that the non-standard CD data is recorded in the second TOC information, it is ignored. In some cases, 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 a CD-R. In order to solve this case, the present invention is provided with the technical idea of the CCCD based on the first and second TOC information described above, and is further adapted to a CD-ROM drive in which the technical idea of the CCCD does not function. By applying a new modulation device and a new modulation method as described below, it is possible to surely prevent the original CD 10 from being copied onto a CD-R.
[0081]
Since a commercially available music CD player (not shown) does not support the optical disk having the multi-session structure as described above, the music CD player can reproduce the original CD 10 having the technical idea of the CCCD without any problem. .
[0082]
Next, a modulation device and a modulation method of the present embodiment according to the present invention will be described with reference to FIGS.
[0083]
FIG. 11 is a block diagram (part 1) schematically showing a modulation device and a modulation method according to the present embodiment according to the present invention.
FIG. 12 is a block diagram (part 2) schematically illustrating a modulation device and a modulation method according to the present embodiment according to the present invention.
FIGS. 13 to 15 show a case where a codeword string is generated by adding a combination bit between one codeword and the next codeword using the modulator of the present embodiment according to the present invention. While allowing the maximum run length 12T that does not satisfy the run length restriction rule in the CD standard, the next code word following one code word and the next next code word are read ahead, and a large number of sets of code word strings are read. FIG. 7 is a diagram for explaining a state where each DSV value is calculated;
FIG. 16 is a diagram showing a difference in a frequency spectrum caused by a change in a DSV value of a codeword string between the case of the original CD according to the embodiment of the present invention and the case of a CD-R obtained by copying the original CD.
[0084]
The modulator 30 of the present embodiment shown in FIGS. 11 and 12 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, It is roughly composed of a two-combined-bit adding circuit 37B, a second DSV value calculating circuit 38B, a DSV value comparing circuit / combined bit selecting circuit 39, and a decision code word string output circuit 40.
[0085]
The first and second combined bit addition circuits 37A and 37B have the same internal structure, and the first and second DSV value calculation circuits 38A and 38B also have the same internal structure. Depending on the control software for operating the 30, the first and second combined bit adding circuits 37 A and 37 B and the combined bit adding circuits (37... Although it can be configured as a DSV value calculation circuit (38 ... not shown), it is separated here as described above for easy understanding of the description.
[0086]
Then, in the modulation device 30 of this embodiment, the input data word of p bits = 8 bits is converted into the code word C of q bits = 14 bits, and r bits = 3 bits between adjacent code words C, C When the EFM signal 1 shown in FIG. 1 (b) is generated by adding the combined bit 1b of FIG. 1 and this EFM signal 1 is recorded on the original CD 10 (FIGS. 9 and 10), first, FIG. As described above, the CCCD is provided by adding a copy protection effect 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. And at least the next code word Cy following the one code word Cx and the next code word Cz are read ahead, and between the one code word Cx and the next code word Cy. Run length While strictly adhering to the limit rule RLL (2, 10), while allowing a minimum run length of 3T to a maximum run length of 12T, a plurality of sets of combination bits 1b of 3 bits are temporarily added to generate a plurality of sets of codeword strings, Furthermore, the minimum run length 3T is also set between the next code word Cy and at least the next next code word Cz in the plurality of sets of code word strings without strictly observing the run length restriction rule RLL (2, 10). A code word sequence from one code word Cx to the next code word Cz through at least the next code word Cy by temporarily adding a plurality of sets of combination bits 1b of 3 bits while allowing the maximum run length 12T. Are generated, and a set of codeword strings whose absolute value of DSV is closest to zero is selected from among the set of codeword strings, and one code in the set of codeword strings is selected. The word Cx and the next codeword C And using a combination bit 1b added between the first and second code words Cx to the next code word Cy via the combination bit 1b to output one finally determined code word sequence, An EFM signal 1 generated by connecting a large number of the decision code word strings is recorded on the original CD10.
[0087]
More specifically, in the modulation device 30 of the present embodiment, the frame synchronization signal generator 31 for generating the 22-bit frame synchronization signal 1a described above 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).
[0088]
Further, the sub-code data SD before modulation corresponding to the sub-code 1c described above with reference to FIG. 1 (b) is converted by the sub-code encoder 32 into a predetermined format shown in FIGS. 4 (a) and 4 (b). It is generated into 8 bits and input to the 8-14 modulation circuit 36.
[0089]
Also, 16-bit PCM audio data PCMAD and compressed audio data CAD obtained by compressing the PCM audio data PCMAD by applying a known compression technique are prepared in advance as the music original data AD. The data PCMAD is selectively input to a cross interleave read-solomon code (CIRC) encoder 35 via one terminal of a changeover switch 34. The compressed audio data CAD is processed by the ROM formatter 33 so as to conform to the format defined by the CD-ROM standard, and is selectively input to the CIRC encoder 35 via the other terminal of the changeover switch 34. .
[0090]
In the CIRC encoder 35, the PCM audio data PCMAD input via one terminal of the changeover switch 34 is subjected to error correction code processing by combining two systems of Reed-Solomon codes, and an 8-bit signal including an error correction code is processed. Are input to the 8-14 modulation circuit 36. The compressed audio data CAD input via the other terminal of the changeover switch 34 is subjected to substantially the same processing as the PCM audio data PCMAD so that each 8-bit input data word D including an error correction code is converted. The signal is sent to the 8-14 modulation circuit 36.
[0091]
Next, in the 8-14 modulation circuit 36, 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 original CD (optical disc) 10 having the multi-session structure described above with reference to FIG. And 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). Things.
[0092]
Further, in the 8-14 modulation circuit 36, the input PCM audio data PCMAD and the compressed audio data CAD and the 8-bit input data word D such as an error correction code are converted into 14-bit input data words D based on the encoding table shown in FIG. When sequentially converting into the code word C, unlike the conventional example described above with reference to FIG. 6, one code word Cx is read, and the next code word Cy following the one code word Cx and the next next code word Cy are read. At least the code word Cz is read ahead.
[0093]
Note that, in the following, an embodiment will be described in which prefetching is performed up to the next codeword Cy and the next codeword Cz following one codeword Cx, but the present invention is not limited to this and illustration is omitted here. However, it is also possible to pre-read a codeword further ahead than the next codeword Cz.
[0094]
Then, one codeword Cx and the next codeword Cy are input from the 8-14 modulation circuit 36 to the first combination bit addition circuit 37A, and the next codeword Cy is output after the next codeword Cy is output. Cz is input from the 8-14 modulation circuit 36 to a second combined bit addition circuit 37B described later.
[0095]
Next, in the first combined bit addition circuit 37A, 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 are not strictly adhered to. In this example, four sets of (000), (001), (010), and (100) are prepared as candidates for the 3-bit combined bit 1b while allowing the minimum run length 3T to the maximum run length 12T. Also in this embodiment, as in the conventional example, in the sets (011), (101), (110), and (111) other than the four sets described above, two or more “1” s appear continuously or “ Since “1” and “0” appear alternately and do not satisfy the minimum run length 3T, they are deleted.
[0096]
Then, in order to combine one code word Cx input into the first combined bit addition circuit 37A and the next code word Cy, four sets of combined bits (000) are interposed between the code words Cx and Cy. ), (001), (010), and (100) are temporarily added to generate a plurality of sets of codeword strings.
[0097]
At this time, as shown in FIGS. 13 to 15, when one codeword Cx and the next codeword Cy are set to the same value as the conventional one in order to easily explain the gist of the present invention, one codeword is used. The twelfth to fourteenth bits of the word Cx are “010”, while the next code word Cy is “00100010000010”. The 13th bit of one codeword Cx is “1”, and the third bit of the next codeword Cy is “1”. The three sets of combined bits (000), (001), and (010) are satisfied because they satisfy the minimum run length 3T to the maximum run length 12T, and the fourth set of combined bits (100) have the minimum run length 3T. Stop adding because you are not satisfied.
[0098]
Then, three sets of connection bits (000), (001),
After adding (010), the three sets of codeword strings {Cx (000) Cy}, {Cx (001) Cy}, and {Cx (010) Cy} are input to the first DSV value calculation circuit 38A, and three sets are obtained. Is calculated, the DSV value of the code word string {Cx (000) Cy} is obtained when the combination bit (000) is added between the code words Cx and Cy as shown in FIG. Is +2, and when the combination bit (001) is added between the code words Cx and Cy as shown in FIG. 14, the DSV value of the code word string {Cx (001) Cy} becomes -4. As shown in FIG. 15, when the combination bit (010) is added between the code words Cx and Cy, the DSV value of the code word sequence {Cx (010) Cy} becomes -6. Up to this stage, it is the same as the conventional example described earlier with reference to FIGS. 6 and 7. In the conventional example, at this stage, a set of code word strings {Cx (000) whose absolute value of the DSV is closest to zero is obtained. ) Cy} is selected as one finally determined code word sequence, but in the present embodiment, as described above, the next code word Cy following the one code word Cx and the next next code word Cz Is read ahead, one code word Cx and the next code word are considered in consideration of the DSV value obtained when one code word Cx is connected to the next code word Cz via the next code word Cy. After selecting and adding the combination bit 1b between the code word and Cy, a code word sequence from one code word Cx to the next code word Cy via the combination bit 1b is finally determined.
[0099]
Therefore, three sets of code word strings {Cx (000) Cy}, {Cx (001) Cy}, and {Cx (010) Cy} obtained by calculating each DSV value in the first DSV value calculation circuit 38A are added with the second combination bit. The signal is input to the circuit 37B.
[0100]
Similarly to the first combination bit addition circuit 37A, the second combination bit addition circuit 37B described above has (000), (001), (000), (001), Four sets of (010) and (100) are prepared.
[0101]
Then, in the second combined bit addition circuit 37B, the three sets of codeword strings {Cx (000) Cy}, {Cx (001) Cy}, {Cx (010) Cy} input here are input here. The four combined bits (000), (001), (010), and (100) are temporarily added between the next code word Cz and the first combined bit addition circuit 37A. Also generates a large number of sets of codeword strings. At this time, a large number of sets of codeword strings are encoded in a branching structure (tree structure), so that one codeword Cx passes through the next codeword Cy and the next codeword Cz in common. Up to the code word string.
[0102]
Here, as shown in FIGS. 13 to 15, the next code word Cy is “00100010000010” as described above, while the next code word Cz is “000000001000001”. The 13th bit of the next codeword Cy is “1”, and the 8th bit of the next codeword Cz is “1”. The third combination bit (000), (001), (010) satisfies the minimum run length 3T to the maximum run length 12T, but the fourth combination bit (100) does not satisfy the minimum run length 3T. Stop adding.
[0103]
Then, between the three sets of codeword strings {Cx (000) Cy}, {Cx (001) Cy}, {Cx (010) Cy} and the next codeword Cz input here, 3 After adding the combination bits (000), (001), and (010), nine code word strings {Cx (000) Cy (000) Cz} and {Cx (000) Cy (001) in total 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 9 codes are set. When calculating each DSV value of the word string,
In the case of the code word sequence {Cx (000) Cy (000) Cz} in case 11 shown in FIG. 13A, the code word Cz of the code word Since the number of "0" s up to the 7th bit is eleven consecutive, it includes the maximum run length 12T, and the DSV value of the code word string {Cx (000) Cy (000) Cz} becomes -3.
In the case of the code word string {Cx (000) Cy (001) Cz} in case 12 shown in FIG. 13B, the code word string {Cx (000) Cy (001) is not included without the maximum run length 12T. The DSV value of Cz｝ becomes +3,
Also in the case of the code word string {Cx (000) Cy (010) Cz} in case 13 shown in FIG. 13C, the code word string {Cx (000) Cy (010) Cz does not include the maximum run length 12T. The DSV value of｝ is +5.
[0104]
Further, in the case of the code word sequence {Cx (001) Cy (000)} Cz in case 21 shown in FIG. 14A, the code word from the thirteenth bit of the code word Cy via the combination bit (000) Since the number of "0" s up to the 7th bit of Cz is eleven consecutive, it includes the maximum run length 12T, and the DSV value of the code word string {Cx (001) Cy (000) Cz} becomes +1.
In the case of the code word string {Cx (001) Cy (001) Cz} in case 22 shown in FIG. 14B, the code word string {Cx (001) Cy (001) is not included without the maximum run length 12T. The DSV value of Cz｝ becomes -5,
Also in the case of the code word string {Cx (001) Cy (010) Cz} in case 23 shown in FIG. 14C, the code word string {Cx (001) Cy (010) Cz does not include the maximum run length 12T. The DSV value of｝ is -7.
[0105]
Further, in the case of the code word string {Cx (010) Cy (000) Cz} in case 31 shown in FIG. 15A, the code word is transmitted via the combination bit (000) from the 13th bit of the code word Cy. Since the number of "0" s up to the 7th bit of Cz is eleven consecutive, it includes the maximum run length 12T, and the DSV value of the code word string {Cx (010) Cy (000) Cz} becomes -1. ,
In the case of the code word string {Cx (010) Cy (001) Cz} in case 32 shown in FIG. 15B, the code word string {Cx (010) Cy (001) is not included in the maximum run length 12T. The DSV value of Cz｝ becomes -7,
Also in the case of the code word string {Cx (010) Cy (010) Cz} in case 33 shown in FIG. 15C, the code word string {Cx (010) Cy (010) Cz does not include the maximum run length 12T. The DSV value of｝ is -9.
[0106]
Thereafter, the nine sets of code word strings from the second DSV value calculation circuit 38B and the respective DSV values corresponding thereto are input to the DSV value comparison circuit / combination bit selection circuit 39, and the DSV value comparison circuit / combination bit selection circuit is used. At 39, a codeword string {Cx (001) Cy (000) Cz} having a DSV value = + 1 whose absolute value of the DSV is closest to zero among the DSV values of the nine sets of codeword strings, or a DSV value = One of the sets of the code word string {Cx (010) Cy (000) Cz} having −1 is selected and input to the decision code word string output circuit 40. At this time, the set whose absolute value of DSV is closest to zero is selected from the set including the maximum run length 12T as shown in FIGS. 13 (a), 14 (a) and 15 (a). it is obvious.
[0107]
When the code word string is selected by the DSV value comparison circuit / combined bit selection circuit 39, if the absolute value of the DSV of the code word string is the same, the code word string of the DSV value on the + side is adopted. If it is determined in advance in the modulation device 30 whether to use the code word string of the DSV value on the minus side or the code word string on only one of the + side and one side, it can be automatically selected. Further, it is possible to select the combination bit 1b corresponding to the code word string on only one side.
[0108]
Next, the decision code word string output circuit 40 adds a code word between one code word Cx and the next code word Cy in one set of code word strings selected by the DSV value comparison circuit / combination bit selection circuit 39. One determined code word sequence {Cx (001) Cy} finally determined by combining one code word Cx to the next code word Cy via the combined bit 1b using the combined bit 1b thus obtained, or One of the determined code word strings {Cx (010) Cy} is output. In other words, this is equivalent to a state in which the combination bit 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 / combination bit selection circuit 39.
[0109]
That is, the code word string {Cx (001) Cy (000) Cz} having the DSV value = + 1 or the code word string {Cx (010) having the DSV value = −1 input to the decision code word string output circuit 40. Cy (000) Cz} is that the combination bit 1b added between the code words Cx and Cy is (001) or (010), and one code word Cx passes through the next code word Cy and the next next bit. 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 considered is closest to zero.
[0110]
On the other hand, as in the conventional example described with reference to FIG. 6, the combined bit added between the code words Cx and Cy using the conventional modulation device 20 that pre-reads only one code word Cx and the next code word Cy. When 1b is (000), as shown in FIGS. 12 and 13 (a) to (c), even if the DSV value temporarily becomes small, the next codeword Cz is immediately reached beforehand. The DSV value becomes larger on the + side or-side than in the case of the present embodiment that performs pre-reading.
[0111]
By the way, in order to generate the maximum run length 12T in the combination of the code word C and the combination bit 1b, as shown in “Cy and Cz” in FIGS. It is sufficient that the code word C is such that when the combination bit 1b is added, the number of "0" including the combination bit 1b can be 11 consecutive.
[0112]
Thereafter, in this embodiment, the determined code word sequence {Cx (001) Cy...} Or the determined code word sequence {Cx (010) Cy...} Controlled so that the DSV value is the best is suitable for recording. The recording signal R is converted into a recording signal R (FIG. 1), and is recorded on a glass master disk for CD (not shown) by a laser beam. Then, a stamper disc (not shown) is manufactured based on the glass master disc for CD, and the original CD 10 of the present embodiment as shown in FIGS. 9A and 9B is used by using the stamper disc. Has been produced.
[0113]
The basic operation of the modulation device and the modulation method according to the present invention has been described with reference to specific examples. However, for the sake of simplicity of description, in calculating the DSV value, codeword strings {Cx (000) Cy}, {Cx (000) Cy (000) Cz}, and {Cx (000) Cy (000) ) Cz...｝, Such that the already calculated code word string is again subjected to the calculation. As a result, unless all the code words Cx, Cy, Cz... Are input, not only the DSV value cannot be calculated, but also the determined code word string can be output. For the determined DSV value of the code word string, a DSV value storage circuit (not shown) is provided in the DSV value calculation circuits 38A and 38B or the DSV value comparison circuit / combination bit selection circuit 39 to prevent duplication of the DSV value calculation. The configuration is such that one decision code word string can be obtained if at least three code words are input.
[0114]
From the above, the modulation apparatus of the present invention capable of generating a maximum run length of 12T when generating a codeword string by adding a 3-bit combination bit 1b such that the DSV value is the best between adjacent codewords C, C When 30 is used, the DSV value can take the smallest value in the code word string including the maximum run length 12T as shown in FIGS.
[0115]
On the other hand, when the conventional modulation device 20 (FIG. 6) that does not allow the maximum run length 12T is used, the DSV value is higher than when the maximum run length 12T is allowed as shown in FIGS. Is apparent from the above. Here, the maximum run length 12T has been described as an example in which the run length restriction rule in the CD standard is not strictly adhered to. However, the present embodiment is also applicable to a long run length of 13T or more and a short run length of 2T or less. And the DSV value of the codeword string can be made smaller than that in the case where the conventional modulation device 20 is used. However, as described in the related art section, it is not preferable to allow an extremely short run length or an extremely long run length from the viewpoint of transmission characteristics.
[0116]
By the way, when the maximum run length 12T is continuous for a certain period in the available code word string, the conventional modulator 20 has a DSV value as shown in, for example, FIG. 13 (b) or (c). Since the increase occurs continuously, the DSV value of the codeword string may periodically fluctuate significantly during the continuous period. 13 (b) or 13 (c) shows an example in which the DSV value rises to the right, that is, a positive increasing tendency, but the input codewords Cx, Cy, Cz. Also, if the polarity of the determined code word sequence corresponding to the first code word Cx is opposite, the DSV value will decrease to the right, that is, will tend to increase in the negative direction. As a result, when a signal recorded using the conventional modulation device 20 is reproduced, a component of a specific frequency is increased in a reproduced signal of a codeword string, and stable reproduction is impaired. On the other hand, when the modulation device 30 of this embodiment is applied, it is clear that stable reproduction is maintained. Hereinafter, input data corresponding to a specific codeword that causes such a difference is referred to as specific data.
[0117]
Applying this technical idea, it pre-reads from one code word Cx to at least the next next code word Cz via the next code word Cy, and allows the minimum run length 3T to the maximum run length 12T. When the codeword string generated from the specific data is recorded on the original CD 10 (FIGS. 9 and 10), the DSV value of the recorded codeword string is extremely small, so that the reproduction failure does not occur. In the copy recording medium described above, the reproduction data from the original CD 10 described above is converted by the conventional modulator 20 (FIG. 6) into the minimum run lengths 3T to 3T set based on the run length restriction rule RLL (2, 10) according to the CD standard. A codeword string is recorded by adding a 3-bit combination bit 1b between adjacent codewords C and C so as to adhere to the maximum run length 11T. In order, the particular data portion allowing the maximum run length 12T on the original CD10 is a copy recording medium it is clear that increasing the component of a particular frequency in the reproduced signal because the variation becomes large DSV value.
[0118]
This is shown in FIG. As shown in FIG. 16, the reproduction frequency spectrum of the code word string of the specific data part allowing the maximum run length 12T recorded on the original CD 10 is gently attenuated in the low frequency part, whereas When a copy recording medium (CD-R) in which the CD 10 is copied by the conventional modulation device 20 is reproduced, a reproduction frequency spectrum of a code word string of a specific data portion has a specific frequency component increased in a low-frequency portion. The reproduction of the copy recording medium (CD-R) becomes unstable.
[0119]
Then, when the recording track 12 recorded on the original CD 10 is reproduced by a commercially available CD player (not shown), the 14-bit codeword C itself satisfies the standard even if it includes a run length 12T that is not the CD standard. Therefore, no error occurs in the reproduced data. On the other hand, if the run-length restriction rules in the CD standard as shown in FIGS. 13B and 13C and FIGS. 14B and 14C and FIGS. Is generated as an input data word D for a certain period of time, the DSV value of the code word string has a large variation on the optical disk manufactured by the conventional modulation device 20, and one frame length of the code word string or In this embodiment, however, a variation in the DSV value of the code word string is caused by allowing a maximum run length 12T outside the CD standard. Improved and stable regeneration is obtained.
[0120]
Similarly, the user copies the original CD 10 recording the PCM audio data PCMAD (FIG. 11) including the specific data 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. When input to the CD-R drive, the minimum run length set based on the run length restriction rule RLL (d, k) = RLL (2,10) in the conventional modulator 20 (FIG. 6) according to the CD standard. Since (d + 1) T = 3T to the maximum run length (k + 1) T = 11T, a codeword string is generated by adding a 3-bit combination bit 1b. The DSV value of the copied code word sequence has a larger variation than that in the case of using the modulation device 30 (FIGS. 11 and 12) of the present embodiment, and is basically based on the length of one or two frames of the code word sequence. It fluctuates at the specified cycle. 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, the reproduced signal has an adverse effect on the operation of the binarization circuit, tracking or focus servo, and the like. The component of the given specific frequency increases, and the reproduction becomes unstable or cannot be reproduced. Thus, when the original CD 10 is copied onto a copy recording medium (CD-R), it is possible to prevent copyright infringement on the digital information signal. It is known that a large variation in the DSV value of the above-mentioned code word string adversely affects the stability of the reproducing apparatus, as described in the section of the prior art in JP-A-6-197024. Details are omitted here.
[0121]
Next, if PCM audio data PCMAD is used by encoding specific data of an AC signal or a DC signal which cannot be discriminated in terms of hearing, it is more effective for copy protection measures. This case will be described with reference to FIGS. 17 and 18. I do.
[0122]
FIG. 17 (a) shows a case where the original CD of the present invention produced by encoding specific data of an AC signal which cannot be discerned as perceptible as PCM audio data is reproduced, and FIG. 17 (b) shows a CD obtained by copying the original CD of the present invention. A diagram showing a case where -R is reproduced,
FIG. 18A shows a case where an original CD of the present invention produced by encoding specific data of a DC signal which cannot be discerned as perceptible as PCM audio data is reproduced, and FIG. 18B shows a CD obtained by copying the original CD of the present invention. FIG. 14 is a diagram illustrating a case where −R is reproduced.
[0123]
First, as shown in FIG. 17 (a), a signal which cannot be discriminated by perception as PCM audio data PCMAD, for example, specific data consisting of an AC signal of about 22.05 KHz is applied for a predetermined period to the present embodiment shown in FIG. The signal is input to an 8-14 modulation circuit 36 provided in the example modulation device 30. For example, when converting specific data consisting of an AC signal of about 22.05 KHz into a 14-bit codeword C, a minimum run length of 3T to a maximum run length of 12T is allowed without strictly observing the run length restriction rule, and At least the next code word Cy and the next next code word Cz following one code word Cx are read ahead and a combination bit 1b is added to optimize the DSV value to generate one decision code word sequence. This one determined code word string is applied to an original CD 10 (FIGS. 9 and 10) serving as a recording medium according to the present invention. When the original CD 10 is reproduced, the reproduced signal of the code word string does not increase the component of the specific frequency, so that it is reproduced as AC signal data which does not cause any trouble and cannot be discriminated in terms of audibility. So the user does not notice at all. It is to be noted that, as shown in FIG. 17 (a), specific data composed of an AC signal is subjected to fade-in and fade-out processing before and after a predetermined period as shown in FIG. Is also one of the features. Also, as the predetermined period in which the specific data of the AC signal is inserted, in the case of music data, a silent period between songs is suitable.
[0124]
On the other hand, as shown in FIG. 17 (b), when the original CD 10 on which specific data composed of an AC signal is recorded is copied to a CD-R and the CD-R is reproduced, the code word over the predetermined period is reproduced. Since a specific frequency component is increased in the reproduced signal of the column, an unreadable section occurs, and noise of a low frequency component is generated by data interpolation in the reproducing apparatus. The user can know that the CD-R is an abnormal optical disk because the user can hear an unpleasant sound such as "sound" and also prevent copyright infringement on the digital information signal on the copied CD-R. be able to.
[0125]
Next, FIG. 18A shows an example in which the AC signal data shown in FIG. 17A is replaced with specific data composed of a DC signal which cannot be discriminated by perception as PCM audio data PCMAD. When the original CD 10 (FIGS. 9 and 10) serving as the recording medium according to the present invention is reproduced, the reproduction signal of the code word string does not include any specific frequency component, so that there is no problem. In addition, since it is reproduced as DC signal data that cannot be discriminated in terms of audibility, the user does not notice at all. It should be noted that the specific data composed of a DC signal is subjected to fade-in and fade-out processing before and after a predetermined period as shown in FIG. 18A in order to prevent generation of noise before and after the specific data. Is also one of the features. Also, as the predetermined period in which the specific data of the DC signal is inserted, in the case of music data, a silent period between songs is suitable.
[0126]
On the other hand, as shown in FIG. 18B, even when the original CD 10 on which the specific data including the DC signal is recorded is copied to the CD-R, an unreadable section occurs during the predetermined period as described above. I will. Therefore, even in this case, since the copied CD-R cannot be reproduced, copyright infringement of the digital information signal on the copied CD-R can be prevented.
[0127]
Here, when the input data word D to be p-q modulated is music information, and the p-bit input data word D is converted into a q-bit code word C, as described above, it is converted into one code word Cx. When a code word sequence is generated by reading at least the next code word Cy and the next next code word Cz at least in advance, the specific data of the AC signal or the DC signal that cannot be discriminated by the above-described audibility is included in the music information. The case of inserting a music piece into a silent section formed between music pieces will be described more specifically with reference to FIGS.
[0128]
FIG. 19 is a schematic diagram for explaining a silent section between music pieces on a general CD,
FIG. 20 is a schematic diagram for explaining a specific data insertion mode 1 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between songs in the recording medium according to the present invention;
FIG. 21 is a schematic diagram for explaining a specific data insertion mode 2 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between songs in the recording medium according to the present invention;
FIG. 22 is a schematic diagram for explaining a specific data insertion mode 3 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between music pieces on the recording medium according to the present invention;
FIG. 23 is a schematic diagram for explaining a specific data insertion mode 4 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between songs in the recording medium according to the present invention.
[0129]
Here, a case where specific data that cannot be discriminated in terms of audibility is recorded by inserting it into a silent section formed between songs on the original CD 10 (FIGS. 9 and 10) serving as a recording medium according to the present invention. Before explaining this, a silent section in the case of a general CD (Compact Disc) containing music information as reference data for this will be described first.
[0130]
In other words, as shown in FIG. 19, in the case of a general CD containing music information, the TOC (not shown) in the lead-in area (not shown) formed on the inner peripheral side according to the CD standard book “Red Book”. The start address of each song is recorded in advance in the Table of Contents information as the table of contents 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 also have a song number, an index number, an address and the like recorded for each song as shown.
[0131]
More specifically, when a plurality of songs recorded on a CD are generalized and displayed using n (where n is a natural number of 2 or more), for example, among the plurality of songs, for example, an (n−1) th song And the nth tune, a silent section is formed.
[0132]
Also, the song number n-1 corresponding to the (n-1) th song is the n-1th song from the performance end position (not shown) immediately after the performance of the (n-2) th song (not shown) has ended. The performance end position of the music number n-1 corresponding to the (n-1) -th song is recorded up to the performance end position immediately after the end of the performance, and the n-th song and the n-th song It is set in a silent section formed between them. Further, a music number n corresponding to the n-th music is recorded after the performance end position of the music number n-1 corresponding to the n-th music.
[0133]
Also, the index numbers for indicating the order of the movements in the respective songs can be assigned to the (n-1) th song and the nth song from 01 to 99 at the maximum. Are recorded from the position of the start address (not shown) of the (n-1) th music to the end of the performance of the music number n-1 of this music. The index number 01 (-99) in the tune is recorded from the position of the start address of the tune to the performance end position (not shown) of the tune number n of the tune. At this time, the start address (not shown) of the (n-1) th tune and the start address of the nth tune are located in a silent section between the tunes and located before the leading end at which the performance of each tune starts. It is recorded in.
[0134]
Further, in a silent section formed between the (n-1) th song and the nth song, there is a section in which an index number 00 that is not related to each song is recorded. Is set between the performance end position of the music number n-1 of the (n-1) th music and the position of the start address of the nth music.
[0135]
As described above, the (n-1) -th song ends at the performance end position of the song number n-1 of the song. On the other hand, the n-th song starts from the position of the start address of the song.
[0136]
Here, when a song number, an index number, and a start address are recorded for each song corresponding to a plurality of songs recorded in a data area on a track as in the above-described CD, the recording according to the present invention is performed. In the original CD 10 (FIGS. 9 and 10) serving as a medium, for example, identification of an AC signal or a DC signal that cannot be discriminated from the auditory sense within a silent section formed between the (n−1) th song and the nth song. Data is inserted and recorded based on any of the specific data insertion modes 1 to 4 shown in FIGS.
[0137]
First, as shown in FIG. 20, in the case of the specific data insertion mode 1 in the recording medium according to the present invention, for example, on the original CD 10 (FIGS. 9 and 10), for example, the (n-1) th song and the nth song The above-described specific data is inserted and recorded in a silent section formed between the above and the section of index number 00 assigned to the position as described above.
[0138]
As a result, when the original CD 10 in which the specific data is inserted and recorded in the section of index number 00 is entirely copied onto a CD-R (copy recording medium), the copied CD-R also has the (n-1) th tune. When the copied CD-R is played back, the specific data is recorded in the silent section formed between the song and the n-th song, and the specific data is recorded in the section with index number 00. In the same manner as described above, an unreadable section occurs due to the copied specific data and the CD-R becomes unreproducible, so that copyright infringement of the digital information signal on the copied CD-R can be prevented beforehand. .
[0139]
However, when copying the original CD10 recorded by inserting the specific data into the section of index number 00 to a CD-R, the user avoids the silent section between the songs by random access to the original CD10. It is also conceivable to copy a plurality of songs from the start address position to the CD-R. In this case, since the silent section between the songs is not copied on the CD-R, the The specific data recorded in the section of each index number 00 set in the... Are not copied, so that even if the copied CD-R is reproduced, the unreadable section does not occur, and the specification on the original CD 10 is not performed. The data copy protection function will not work on the copied CD-R. In order to avoid this, according to the present invention, even when the user collects a plurality of songs from the position of the start address of each song on the original CD 10 and copies them to a CD-R, each recorded in the silent section between the songs. By adopting any of the specific data insertion modes 2 to 4 shown in FIGS. 21 to 23 described below so that the specific data is always copied, the copy protection function of the original CD 10 can be further improved. Things.
[0140]
That is, as shown in FIG. 21, in the case of the specific data insertion mode 2 in the recording medium according to the present invention, for example, on the original CD 10, it is formed between the (n-1) th music and the nth music. The performance end position of the music number n-1 of the (n-1) th music set in the silent section is set to the start address of the nth music from the performance end position of the music number n-1 in the case shown in FIG. The specific data described above is inserted and recorded between the end of the (n-1) th tune and the performance end position of the tune number n-1 extended here. Accordingly, the section in which the index number 00 is recorded is shortened.
[0141]
Although illustration is omitted here, the performance end position of the music number n-1 of the (n-1) th music is extended until it coincides with the position of the start address of the nth music, and the (n-1) th music is played. Specific data may be inserted and recorded between the end of the music and the performance end position of the music number n-1 extended to the position of the start address. In this case, the index number 00 is recorded. Although the section is deleted, the (n-1) th song ends at the performance end position of the song number n-1, and the nth song starts from the start address position of the nth song which is the same position as this position. It does not cause any trouble.
[0142]
Therefore, when the original CD 10 is manufactured by adopting the technical idea of the specific data insertion mode 2 as shown in FIG. 21, the specific data that cannot be discriminated in terms of audibility is in a silent section formed between music pieces. In addition, the original CD 10 is inserted and recorded in a section other than the section of the index number 00, and the user copies a plurality of songs from the start address of each song to the CD-R with respect to the original CD10. Even in this case, for example, since the (n-1) th song is always copied to the performance end position of the song number n-1, the end of the (n-1) th song on the original CD 10 and the song number n- Since the specific data recorded between the end of the performance 1 is always copied onto the CD-R, if the copied CD-R is reproduced, the CD-R cannot be reproduced due to the specific data. It is as described above. Of course, even if the original CD 10 adopting the technical idea of the specific data insertion mode 2 as shown in FIG. 21 is entirely copied to the CD-R, the specific data is copied following the end of the (n-1) th music piece. It is obvious.
[0143]
Next, as shown in FIG. 22, in the case of the specific data insertion mode 3 in the recording medium according to the present invention, for example, the original data is formed between the (n-1) th music and the nth music on the original CD10. The position of the start address of the n-th song set in the silence section is set to the performance of the song number n-1 of the (n-1) -th song from the start address position of the n-th song in the case shown in FIG. After moving to the end position side, the above-described specific data is inserted and recorded between the position of the start address of the n-th song and the leading end of the song. Accordingly, the section in which the index number 00 is recorded is shortened. Further, in this case, the position of the start address of the n-th song is moved to the (n-1) -th song side, so that the position from the start address of the n-th song to the head of the n-th song is shifted. Although the silent state tends to last a little longer, the section from the start address of the nth song to the beginning of the nth song is set within the time range in which the user can accept the silent state. It will not cause any trouble.
[0144]
Although not shown here, the start address of the n-th song is matched with the performance end position of the song number n-1 of the n-1th song, and the performance of the song number n-1 is ended. Specific data may be inserted and recorded between the start address position of the n-th song matched with the position and the leading end of the n-th song. In this case as well, a section in which index number 00 is recorded Is deleted, but the (n-1) -th song ends at the performance end position of the song number n-1, and the n-th song starts from the position of the start address of the n-th song which is the same position as this position. So there is no trouble.
[0145]
Therefore, when the original CD 10 is manufactured by adopting the technical idea of the specific data insertion mode 3 as shown in FIG. 22, the specific data that cannot be discriminated in terms of audibility is in a silent section formed between music pieces. In addition, the original CD 10 is inserted and recorded in a section other than the section of the index number 00, and the user copies a plurality of songs from the start address of each song to the CD-R with respect to the original CD10. Even in this case, for example, since the data is always copied from the position of the start address of the n-th song, the specific data recorded between the start address of the n-th song and the leading end of the song on the original CD 10 is also CD- Since the copied CD-R is always reproduced on the R, if the copied CD-R is reproduced, the CD-R cannot be reproduced due to the specific data as described above. Of course, even if the original CD 10 employing the technical idea of the specific data insertion mode 3 as shown in FIG. 22 is completely copied to the CD-R, the specific data is copied following the start address of the n-th song. Is obvious.
[0146]
Next, as shown in FIG. 23, in the case of the specific data insertion mode 4 in the recording medium according to the present invention, the specific data insertion mode 1 shown in FIG. 20, the specific data insertion mode 2 shown in FIG. The original CD 10 is produced by combining with the specific data insertion mode 3 shown in FIG. 22, for example, between the end of the (n-1) th song and the performance end position of the song number n-1 of this song. The above-mentioned specific data is inserted and recorded, and the specific data is also inserted and recorded in the section of index number 00, and further, between the position of the start address of the n-th song and the leading end of the song. The specific data is inserted and recorded.
[0147]
Although FIG. 23 shows a case where three sets of the specific data insertion modes 1 to 3 described above are combined, the present invention is not limited thereto, and at least two sets of the specific data insertion modes 1 to 3 are combined. Alternatively, an original CD 10 may be manufactured.
[0148]
Therefore, the original CD 10 produced by combining at least two or more of the above-mentioned specific data insertion modes 1 to 3 can be entirely copied to a CD-R, or the user can record a plurality of songs from the start address of each song. Even if the data is copied onto a CD-R, at least one or more specific data is always copied between the songs on the CD-R. Therefore, when the copied CD-R is reproduced, at least one or more specific data is reproduced. As described above, the CD-R falls into an unreproducible state.
[0149]
In the modulation device, the modulation method, and the recording medium according to the present invention described in detail above, the case of the EFM modulation (8-14 modulation) system used for the CD has been described, but the invention is not limited to the CD standard. , P-bit input data word D is converted into a q-bit code word C, at least the next code word Cy and the next next code word Cz following one code word Cx are read ahead, and The minimum run length (d + 1) T to the maximum run length (k + 2) without strict adherence to the minimum run length (d + 1) T to the maximum run length (k + 1) T set based on the run length restriction rule RLL (d, k) ) Any pq modulation that generates a codeword string by adding an r-bit combination bit 1b with the best DSV value between adjacent codewords C and C to allow T Technology It can be applied to the idea.
[0150]
Further, when the input data word D to be pq modulated is music information and the p-bit input data word D is converted into a q-bit code word C, the next code following one code word Cx is used. A minimum run length (d + 1) T to a maximum run length (k + 1) set based on a predetermined run length restriction rule RLL (d, k) at least pre-read the word Cy and the next code word Cz. R combined bits 1b such that the DSV value is the best between adjacent codewords C and C so as to allow a minimum run length (d + 1) T to a maximum run length (k + 2) T without observing T. Is added to generate a codeword string, and when the pq modulated music information is recorded on the original CD 10 (FIGS. 9 and 10), specific data of an AC signal or a DC signal which cannot be discriminated from the auditory sense is included in the music information. Between songs In order to further enhance the performance of the copy protection function, the specific data described above must be inserted into a silent section formed between music pieces, and recorded. , And should be inserted and recorded in the section excluding the section with index number 00.
[0151]
【The invention's effect】
According to the modulation device, the modulation method, and the recording medium of the present invention described in detail above, a p-bit input data word is converted into a q-bit code word, and an r-bit combination bit is inserted between adjacent code words. When a code word string is generated by adding the code word string to a recording medium such as an optical disk, the copy protection effect is obtained by using TOC information recorded in a lead-in area of the optical disk (recording medium). And at least the next code word following the one code word and the next code word are read ahead, and a plurality of combinations of r bits are connected between the one code word and the next code word. Bits are temporarily added without strictly observing a predetermined run-length restriction rule to generate a plurality of sets of codeword strings, and further, the next codeword in the plurality of codeword strings and at least the next next codeword in the plurality of codeword strings are generated. Between the multiple combinations of r bits Is temporarily added without a predetermined run-length restriction rule to generate a number of sets of codeword strings from at least one codeword to the next next codeword. A set of codeword strings whose absolute value of the DSV value is closest to zero is selected from among the DSV values, and a codeword string between one codeword and the next codeword in the set of codeword strings is selected. Using the combination bits added to the above, one code word is combined with the next code word through the combination bits to output one finally determined code word sequence, and a large number of the determined code word sequences are connected. Is recorded on a recording medium such as an optical disk. When a user intentionally copies this optical disk (recording medium) using a CD-ROM drive in a pan controller, the TOC information Added copy protection effect using In a CD-ROM drive in which the technical concept of the CCD effectively functions, copy protection is immediately attained. On the other hand, a copy recording medium in which a large number of decision code word strings are copied is used in a CD-ROM drive in which the technical concept of the CCCD does not function. When a signal is reproduced, a specific frequency component increases in the reproduced signal, and the DSV value also breaks down so that reproduction cannot be performed. Therefore, it is possible to prevent copyright infringement on a digital information signal on a copy recording medium. On the other hand, a commercially available optical disk drive (for example, a CD player) having no copy function can normally reproduce an original recording medium in which a large number of determination code word strings are recorded without any trouble.
[0152]
Further, by the modulation device of the present invention or the modulation method of the present invention, AC signal data or DC signal data which cannot be discriminated perceptually as an input data word is input over a predetermined period, and this input data word is subjected to pq modulation. When encoded and recorded on a recording medium, if a copy recording medium on which the recording medium is copied is reproduced, an unpleasant sound such as a "geek sound" or a "gear sound" is generated during an unreadable section due to DSV control failure. Therefore, it is possible to notify the user that the copy recording medium is an abnormal recording medium, and to prevent copyright infringement on the digital information signal on the copied recording medium.
[0153]
Further, according to the modulation device, the modulation method, and the recording medium of the present invention, when the input data word is music information and specific data of an AC signal or a DC signal that cannot be discriminated from perception is input over a predetermined period. The specific data may be inserted into a silent section formed between songs and / or the specific data may be inserted into a silent section formed between songs and an index By inserting the data into a section excluding the section of the number 00 and recording it on the recording medium, when the copy recording medium obtained by copying this recording medium is reproduced, an unreadable section occurs due to the copied specific data and the copy recording medium is generated. Therefore, it is possible to prevent copyright infringement on the digital information signal on the copy recording medium.
[Brief description of the drawings]
1A and 1B are diagrams for explaining a signal format of music information recorded on a CD, wherein FIG. 1A shows music original data, and FIG. 1B shows an EFM signal.
FIG. 2 is a diagram showing an encoding table at the time of 8-14 modulation.
FIGS. 3A and 3B are diagrams for explaining DSV control during 8-14 modulation.
FIGS. 4A and 4B are diagrams for explaining a subcode in the EFM signal shown in FIG. 1B; FIG. 4A shows subcode data before modulation; FIG. 4B shows a Q channel in the subcode data; FIG. 3 is a diagram showing a frame structure of FIG.
FIG. 5 is a diagram showing a state in which 98 EFM signals shown in FIG. 1B constitute one block.
FIG. 6 is a block diagram schematically illustrating a conventional modulation device.
FIGS. 7 (a) to 7 (c) show a case where a combined bit is added between one codeword and the next codeword following a predetermined run-length restriction rule using a conventional modulator. FIG. 7 is a diagram for explaining a state in which DSV values of a plurality of sets of code word strings are calculated when (000), (001), and (010) are temporarily added as connection bits when a code word string is generated. is there.
FIG. 8 is a longitudinal sectional view showing an optical disc on which a copy protection measure is taken as an example of a conventional example.
FIGS. 9A and 9B are a perspective view and a longitudinal section for explaining an optical disc serving as a recording medium of the present embodiment according to the present invention.
FIG. 10 is a diagram for explaining a multi-session structure in a recording medium (optical disc) manufactured by applying the modulation device and the modulation method according to the present invention.
FIG. 11 is a block diagram (No. 1) schematically illustrating a modulation device and a modulation method of the present embodiment according to the present invention.
FIG. 12 is a block diagram (part 2) schematically illustrating a modulation device and a modulation method according to the present embodiment according to the present invention.
FIGS. 13 (a) to 13 (c) show the relationship between one code word and the next code word using the modulator of the present embodiment without strictly observing the run-length restriction rule in the CD standard. When a codeword string is generated by adding a combination bit, the next codeword following one codeword and the next codeword are read ahead, and a codeword is interposed between one codeword and the next codeword. And one set of combined bits (000), and three sets of combined bits (000), (001), and (010) are tentatively added between the next codeword and the next codeword. It is a figure for explaining the state where each DSV value of many code word strings was computed at the time.
FIGS. 14 (a) to (c) show a state in which one of a code word and the next code word following the code word are strictly adhered to without using the run-length restriction rule in the CD standard using the modulator of the present embodiment. When a codeword string is generated by adding a combination bit, the next codeword following one codeword and the next codeword are read ahead, and a codeword is interposed between one codeword and the next codeword. Is temporarily added with one set of combination bits (001), and three sets of combination bits (000), (001), and (010) are tentatively added between the next codeword and the next codeword. It is a figure for explaining the state where each DSV value of many code word strings was computed at the time.
FIGS. 15 (a) to (c) show a state in which one of a code word and a next code word following the code word are strictly adhered to without using the run-length restriction rule in the CD standard using the modulation apparatus of the present embodiment. When a codeword string is generated by adding a combination bit, the next codeword following one codeword and the next codeword are read ahead, and a codeword is interposed between one codeword and the next codeword. Is temporarily added with one set of combination bits (010), and three sets of combination bits (000), (001), and (010) are tentatively added between the next codeword and the next codeword. It is a figure for explaining the state where each DSV value of many code word strings was computed at the time.
FIG. 16 is a diagram showing a difference in frequency spectrum caused by a change in the DSV value of a codeword string between the case of the original CD according to the embodiment of the present invention and the case of a CD-R obtained by copying the original CD. .
FIG. 17 (a) shows a case where an original CD of the present invention produced by encoding specific data of an AC signal which cannot be perceived as PCM audio data is reproduced, and FIG. 17 (b) shows a copy of the original CD of the present invention. FIG. 6 is a diagram showing a case where a reproduced CD-R is reproduced.
FIG. 18 (a) shows a case where an original CD of the present invention produced by encoding specific data of a DC signal which cannot be perceived as PCM audio data is reproduced, and FIG. 18 (b) shows a copy of the original CD of the present invention. FIG. 6 is a diagram showing a case where a reproduced CD-R is reproduced.
FIG. 19 is a schematic diagram for explaining a silent section between music pieces on a general CD.
FIG. 20 is a schematic diagram for explaining a specific data insertion mode 1 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between songs in the recording medium according to the present invention.
FIG. 21 is a schematic diagram for explaining a specific data insertion mode 2 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between music pieces in the recording medium according to the present invention.
FIG. 22 is a schematic diagram for explaining a case of specific data insertion mode 3 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between music pieces in the recording medium according to the present invention.
FIG. 23 is a schematic diagram for explaining a specific data insertion mode 4 in which specific data that cannot be discriminated in terms of audibility is inserted into a silent section between music pieces in the recording medium according to the present invention.
[Explanation of symbols]
1 ... EFM signal,
1a: Frame synchronization signal, 1b: Combined bit, 1c: Subcode,
1d: first code word sequence, 1e: C2 error correction code,
1f: second code word string, 1g: C1 error correction code,
10 ... an optical disc serving as a recording medium of the present embodiment according to the present invention;
10a: first session, 10a1: first 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 reflection film,
14 ... Protective film,
20: a conventional modulation device,
21: frame synchronization signal generator, 22: subcode encoder,
23 ... CIRC encoder, 24 ... 8-14 modulation circuit,
25: coupling bit addition circuit, 26: DSV value calculation circuit,
27 DSV value comparison circuit / coupling bit selection circuit
30... The modulation device of the present embodiment,
31 ... frame synchronization signal generator, 32 ... subcode encoder,
33: ROM formatter, 34: changeover switch,
35 ... CIRC encoder, 36 ... 8-14 modulation circuit,
37A: a first combined bit adding circuit; 37B: a second combined bit adding circuit;
38A: first DSV value calculation circuit, 38B: second DSV value calculation circuit,
39 DSV value comparison circuit / coupling bit selection circuit
40 ... decision code word string output circuit,
AD: Music original data,
CAD: compressed audio data, PCMAD: PCM audio data,
D: input codeword, Cx, Cy, Cz: codeword.

Claims (9)

A p-bit input data word is converted into a q-bit code word, and r-bit combination bits are added between adjacent code words to generate a code word sequence, and this code word sequence is recorded on a recording medium. In a modulator for
Copy protection adding means for adding a copy protection effect using TOC information recorded in the lead-in area of the recording medium;
when converting the p-bit input data word into the q-bit code word, a next code word that follows one code word, and a modulation unit that at least pre-reads the next next code word;
Between the one codeword and the next codeword, a plurality of sets of combined bits by the r bits are temporarily added without strictly observing a predetermined run-length restriction rule to generate a plurality of sets of codeword strings, Further, even between the next code word in the plurality of code word strings and at least the next next code word, the plurality of combined bits by the r bits are not strictly adhered to a predetermined run-length restriction rule. Temporary bit addition means for generating a large number of sets of codeword strings from at least one codeword to the next codeword,
DSV value calculation means for calculating each DSV value of a large number of sets of the code word strings generated by the combination bit addition means;
Comparing / selecting means for selecting one set of the codeword strings whose absolute value of the DSV value is closest to zero among the DSV values of the multiple sets of the codeword strings obtained by the DSV value calculating means; When,
Using the combination bits added between the one codeword and the next codeword in the one set of codeword strings selected by the comparison / selection means, And a decision code word string output unit that outputs one decision code word string that is finally determined by combining up to the next code word through
Specific data that will include a specific frequency component is input to the code word string output in strict observance of the run length restriction rule over a predetermined period as the input data word. A modulation device for outputting a codeword string without strictly observing a run-length restriction rule. The modulation device according to claim 1,
The modulation device according to claim 1, wherein the specific data is AC signal data or DC signal data that cannot be discriminated by hearing. The modulation device according to claim 1 or 2,
When the input data word is music information, and when the specific data which cannot be distinguished in terms of audibility is input for a predetermined period, the specific data is inserted into a silent section formed between songs. A modulation device characterized by the above-mentioned. The modulation device according to claim 1 or 2,
When the input data word is music information, and when the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is included in a silent section formed between songs. And a modulator inserted in a section excluding the section of index number 00. A p-bit input data word is converted into a q-bit code word, and r-bit combination bits are added between adjacent code words to generate a code word sequence, and this code word sequence is recorded on a recording medium. In the modulation method for
A copy protection adding step of adding a copy protection effect using the TOC information recorded in the lead-in area of the recording medium;
when converting the p-bit input data word into the q-bit code word, a modulation step of at least pre-reading a next code word following one code word and a next next code word;
Generating a plurality of sets of codeword strings by temporarily adding a plurality of sets of combination bits by the r bits between the one codeword and the next codeword without strictly observing a predetermined run-length restriction rule; Further, even between the next codeword in the plurality of codeword strings and at least the next next codeword, a plurality of sets of combination bits by the r bits are not strictly adhered to a predetermined run-length restriction rule. A combined bit adding step of generating a large number of sets of codeword strings from at least one codeword to the next next codeword;
A DSV value calculating step of calculating each DSV value of the multiple sets of the code word strings generated in the combining bit adding step;
A comparing / selecting step of selecting one set of the codeword strings whose absolute value of the DSV value is closest to zero among the DSV values of the multiple sets of the codeword strings obtained in the DSV value calculating step; When,
Using a combination bit added between the one codeword and the next codeword in the one set of codeword strings selected in the comparison / selection step, the combination bits from the one codeword are used. A decision code word sequence output step of outputting one decision code word sequence finally determined by combining up to the next code word through
Specific data that includes a component of a specific frequency is input to the code word string output in strict observance of the run-length restriction rule over a predetermined period as the input data word, and the period is A modulation method for outputting a codeword string without strictly observing a run-length restriction rule. The modulation method according to claim 5,
The modulation method according to claim 1, wherein the specific data is AC signal data or DC signal data that cannot be discriminated in terms of hearing. In the modulation method according to claim 5 or 6,
When the input data word is music information, and the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is inserted into a silent section formed between songs. A modulation method, comprising: In the modulation method according to claim 5 or 6,
When the input data word is music information, and the specific data which cannot be discriminated in terms of audibility is input for a predetermined period, the specific data is included in a silent section formed between songs. A modulation method characterized by being inserted in a section excluding the section of index number 00. A recording medium recording the code word sequence encoded by the modulation device according to claim 1 or the modulation method according to claim 5.

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