JP2002184101A - Method of preventing copying of code information, coding equipment and decoding equipment as well recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the compatibility of copyright protection with the convenience of a user when copying digital signals. SOLUTION: The high-quality digital signals subjected to analog-to-digital conversion with 24 bits is subjected to digital-to-analog conversion by a digital- to-analog converter 45 and the analog signals are outputted through an output terminal 55. The high-quality digital signals are added with copyright data relating to their data and are outputted through a digital output terminal 90.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for converting analog information such as an audio signal into an analog signal with a certain quantization bit number.
Digital information (A / D) conversion to be recorded on a recording medium or transmitted via a transmission medium, a copy protection method for code information for preventing and managing copying of digital data, encoding device, decoding device, and recording medium About.

[0002]

2. Description of the Related Art C as an optical disc for audio reproduction
More than ten years have passed since D (Compact Disc) came on the market, and as a recording medium for audio information, it has already shown remarkable spread over conventional cassette tapes. The physical / logical format of a CD which is a digital disk is an EF of an 8-bit fixed data length symbol.
M modulation recording system, subcode, audio data, CR
Established as a data format such as C
CD players to which various application functions are added have been developed.

A CD is also used as a data CD-ROM by discriminating it by control bits (4 bits) of the Q channel in the subcode or by discriminating the absence of TOC. Its application is expanding in the field of electronic publishing by making effective use of the large capacity and high-speed accessibility of disks. By the way, in the above CD-ROM, the audio is ADP
It is compressed by CM, and the original sound quality cannot be reproduced by the compression, so that a recording with higher fidelity has been demanded. In other words, even a compressed CD
It is expected that a disc capable of recording an audio signal equivalent to twice the bandwidth of a disc will appear.

[0004] However, when such high-quality Hi-Fi signals are copied in the form of digital information, they are convenient for the user because they do not deteriorate, but they are not desirable from the viewpoint of copyright protection. . In addition,
As a method of solving such a problem, a method of limiting the number of times of copying digital information, a method of not providing a digital output terminal at all in a device, and the like have been proposed.

[0005]

However, it is difficult to achieve both user convenience and copyright protection by limiting the number of times of copying digital information or by not providing a digital output terminal in a device at all. There is a problem. By the way, copying of high-quality digital data that has been A / D-converted with a relatively large number of quantization bits is not permitted, but copying of low-quality digital data having a substantially small number of quantization bits is permitted. There is a good idea.

There is also the idea that copyright data may be added to such an extent that the quality of high-quality digital data is not degraded, and copying may be permitted if the copyright holder can prove that the product is a duplicate. . Further, in analog copy, since copyright-related information such as copy number restriction information included in digital data is not included, data once analog-copied may be copied thereafter without limitation. It is not preferable from the viewpoint of protection.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a code information copy prevention method, an encoding device, a decoding device, and a recording medium that can achieve both user convenience and copyright protection.

[0008]

Means for Solving the Problems In order to achieve the above object, the present invention comprises the following means 1) to 13). That is, 1) a step of A / D converting an analog signal to generate first digital data, and a second step of adding copyright data related to the first digital data to the first digital data.
Transmitting copyright data from the second digital data and modulating the copyright data; extracting the first digital data from the second digital data and converting it to an analog signal Outputting the digital data only in a state of the digital data obtained by adding the modulated copyright data to the first digital data. 2) A / D conversion of an analog signal to generate first digital data, and a second method in which copyright data relating to the first digital data is added to the first digital data.
Transmitting copyright data from the second digital data and modulating the copyright data; extracting the first digital data from the second digital data and converting it to an analog signal Outputting the digital data only in the state of the digital data obtained by adding the modulated copyright data to the first digital data; and outputting the analog data when the copyright data is not accompanied by the copy number limitation. A step of D / A-converting and outputting only the second digital data with respect to the signal; and an step of outputting the second digital data when the copyright data is accompanied by a limitation on the number of copies. Is controlled so that the second digital data is not D / A converted or is not output after D / A conversion. Steps and the have copy protection method code information that. 3) A / D conversion means for A / D converting an analog signal to generate first digital data, and an A / D converter having a predetermined encoding format in which copyright data relating to the first digital data is added to the first digital data. And an output means for outputting digital data. 4) A code information decoding device for decoding second digital data in which copyright data relating to the first digital data generated by A / D conversion of an analog signal is added to the first digital data, The first digital data is extracted from the second digital data and D /
D / A conversion means for A / A conversion, an analog signal output terminal for outputting an analog signal D / A converted by the D / A conversion means, and copyright data extracted from the second digital data and modulated. Modulating means, adding means for adding the copyright data modulated by the modulating means to the first digital data, and a digital signal output terminal for outputting the output of the adding means in the form of digital data; A code information decoding device configured not to output the first digital data to which the copyright data modulated by the modulation means is not added. 5) A code information decoding device for decoding second digital data in which copyright data relating to the first digital data generated by A / D converting an analog signal is added to the first digital data, The first digital data is extracted from the second digital data and D /
D / A conversion means for A / A conversion, an analog signal output terminal for outputting an analog signal D / A converted by the D / A conversion means, and copyright data extracted from the second digital data and modulated. A modulating means, an adding means for adding the copyright data modulated by the modulating means to the first digital data, a digital signal output terminal for outputting the output of the adding means in the form of digital data, When the data is not accompanied by the copy number limitation, only the second digital data is converted to D for analog signals.
When the copyright data is accompanied by a copy number limit, the output of the second digital data is permitted, but the output of the second digital data is permitted.
Control means for not performing D / A conversion or not outputting after D / A conversion, wherein the first digital data to which the copyright data modulated by the modulation means is not added is provided. Code information decoding device configured not to output the code information. 6) A recording medium in which digital data generated by A / D conversion of an analog signal is recorded as second digital data in a predetermined encoding format in which copyright data relating to the data is added. 7) A / D converting an analog signal to generate first digital data; modulating copyright data relating to the first digital data; and converting the copyrighted data modulated to the first digital data. Transmitting, via a medium, second digital data in a predetermined encoding format to which the right data has been added; converting the second digital data into an analog signal and outputting the analog data; A code information copy protection method that is output only in the data state. 8) A / D converting an analog signal to generate first digital data, modulating copyright data relating to the first digital data, and writing the modulated copyrighted data to the first digital data. Transmitting, via a medium, second digital data in a predetermined encoding format to which copyright data has been added, and when the copyright data is not accompanied by a copy number limit, only the second digital data for an analog signal is output. D / A conversion and output; and when the copyright data is accompanied by a limit on the number of copies, the output of the second digital data is permitted, but for analog signals, the second digital data is converted to a digital signal. / A conversion is not performed or the output is not output after the D / A conversion. Copy protection method for coding information to be output only when the digital data. 9) A / D conversion means for A / D converting an analog signal to generate first digital data, modulation means for modulating copyright data relating to the first digital data, and Output means for outputting second digital data to which the copyright data modulated by the modulation means is added. 10) An analog signal is A / D converted to generate first digital data, and copyright data related to the first digital data is modulated. The modulated copyright data is converted to the first digital data. Second added
A code information decoding device for decoding the digital data of the second digital data, a D / A conversion means for D / A conversion of the second digital data, and a D / A conversion by the D / A conversion means.
An analog signal output terminal that outputs the converted analog signal, and a digital output terminal that outputs the second digital data, wherein the first digital data to which the modulated copyright data is not added is Code information decoding device configured not to output. 11) An analog signal is A / D converted to generate first digital data, and copyright data relating to the first digital data is modulated, and the modulated copyright data is converted to the first digital data. Second added
A code information decoding device for decoding the digital data of the second digital data, a D / A conversion means for D / A conversion of the second digital data, and a D / A conversion by the D / A conversion means.
An analog signal output terminal for outputting the converted analog signal; and a digital output terminal for outputting the second digital data. When the copyright data is not accompanied by a copy frequency limit, the analog signal is output to the second terminal. When only the digital data is D / A-converted and output, on the other hand, when the copyright data is accompanied by a limit on the number of copies, the output of the second digital data is permitted, but the output of the second digital data is allowed for analog signals. Control means for controlling not to D / A convert the data or to output the data after the D / A conversion, and to not output the first digital data to which the modulated copyright data is not added. Code information decoding device. 12) The analog signal is A / D converted to generate first digital data, and copyright data related to the first digital data is modulated. The modulated copyright data is converted to the first digital data. Second added
A recording medium on which digital data is recorded. 13) The method according to any one of claims 1, 2, 7, and 8, wherein the modulating step spreads copyright data in a spectrum.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an encoder for realizing a first reference example of the code information copy protection method according to the present invention, FIG. 2 is a block diagram showing the signal processing circuit 32 of FIG. 1 in detail, and FIG. FIG. 4 is an explanatory diagram showing a sampling cycle and a data string of an A / D converter, FIG. 4 is an explanatory diagram showing user data packed by the allocation circuit of FIG. 2, and FIG. 5 is a first example of a code information copy protection method according to the present invention. 6 is a block diagram showing the signal processing circuit of FIG. 5 in detail, and FIG. 7 is an explanatory diagram showing a data stream decoded by the decoder of FIG. 6 and a sampling period.

An analog signal such as an audio signal is input to an input terminal IN shown in FIG.
The sampling is performed by the / D converter 31 at a sufficiently high sampling frequency (sampling period Δt shown in FIG. 3), for example, 192 kHz enough to prohibit copying, and is converted into a 24-bit high resolution PCM signal, for example, as shown in FIG. Are converted into the data strings xb1, x1, xa1, x2, xb2, x3, xa2,..., Xbi, x2i-1, xai, x2i,.

This data string (xbi, x2i-1, xai, x2
i) is a signal processing circuit 32 and a memory 3 shown in detail in FIG.
3 and then the DVD encoding circuit 34
Packed by. This packing data is output to the output terminal OUT1, or is modulated by the modulation circuit 35 in a modulation method according to the medium and output to the output terminal OUT2.

The configuration of the signal processing circuit 32 will be described in detail with reference to FIG. First, a low-pass filter 36 for passing a half band, for example, an FIR filter, is used as shown in FIG.
(Xbi, x2i-1, xa)
i, x2i), a data sequence xc1, *, *, *, xc2, *, *, *, xc3, *, *, corresponding to the band-limited curve β
, Xci, *, *, *,..., And by thinning out the data “*” from the data string by the thinning circuit 37, the data string xc1, xc2, xc3,. , Xci, ... are generated. In addition, data strings (xbi, x2i-1, xai, x
2i), the data sequence xb1, xa1, xb2, xa2,..., Xbi, xai,.

These data strings xci, xbi, x
Based on ai, a difference xbi-xci = [Delta] 1i xai-xci = [Delta] 2i is calculated by a difference calculator 39 formed by an adder. Here, the difference data Δ1i and Δ2i are, for example, 2
It is 4 bits or less, and the number of bits may be fixed or variable. The allocation circuit 40 packs the data sequence xci and the difference data Δ1i, Δ2i as user data as shown in FIG. 4 and outputs the user data to be recorded on a recording medium, for example, a DVD (digital video disk). Are transmitted to the transmission path. When the user data is 2034 bytes like a DVD, the data xci and the difference data Δ1i and Δ2i are both 22 bytes.
There are five, and the subheader is 9 bytes. Here, the data sequence xci is a data sequence in which the sampling frequency is reduced to ４ by limiting the band of the digital data A / D converted by the A / D converter 31.

Next, the decoder will be described with reference to FIG. The input signal is first supplied to the modulation circuit 35 on the encoder side.
The signal is demodulated by the demodulation circuit 41 in accordance with the modulation method described above, and is then decoded by the DVD decoding circuit 42. And switch 51
Is applied to In the signal processing circuit 43, as shown in FIG. 6, first, the adder 46 calculates Δ1i + xci = xbi Δ2i + xci = xai to restore the data strings xbi and xai. Here, the data strings xbi and xai are the original 24 bits.

Next, in the interpolation processing circuit 47, the data string xa
Using a plurality of data i and xbi, a data sequence xi therebetween is interpolated as shown in FIG. The interpolation processing circuit 4
In step 7, the interpolation data sequence xi can be obtained by filling the 0 data and passing through a low-pass filter using, for example, an upsampling method. The interpolation data sequence xi may be obtained by curve approximation or prediction approximation. In this case, it is possible to increase the degree of approximation by additionally transmitting the approximation auxiliary data.

The data thus interpolated is arranged as xb1, x1, xa1, x2, xb2, x3, xa2,..., Xbi, x2i-1, xai, x2i,. D / A converter 45 and adder 56
Is applied to In the D / A converter 45, the input data is converted into an analog signal at a sampling frequency of 192 kHz and output via an analog output terminal 55.

On the other hand, the data strings (xbi, x2i-1, xai, x
Dither noise is generated from the dither generator 57 as random noise for substantially limiting the number of quantization bits (24 bits) of each data of 2i) to, for example, about 16 bits. In the adder 56, the dither noise and the data string (xb
i, x2i-1, xai, x2i) are added and output via the output terminal 53. Note that the dither noise and the data string (x
Instead of simply adding bi, x2i-1, xai, x2i), dither noise is added after the lower 17 bits of the 24-bit data of the data string (xbi, x2i-1, xai, x2i) are truncated. You may. Further, the S / N ratio of the data sequence (xbi, x2i-1, xai, x2i) may be degraded by adding white noise or pink noise instead of dither noise.

Therefore, the data string (xbi, x2i-1, xai, xai) is subjected to A / D conversion with a 24-bit quantization bit number, encoded, recorded on a recording medium, and decoded.
In 2i), since the S / N ratio is deteriorated and output as digital data, it is possible to prevent copying with a high quality quantization bit number. DVD decoding circuit 4
The output data strings xci, Δ1i, and Δ2i are output to a digital output terminal 52 via a switch 51, and a terminal 49 for inputting a personal identification number, and decrypting the personal identification number input via the terminal 49. A decryption unit 50 is provided for turning on the switch 51 in the event of a failure. Therefore,
Only the specific person can copy the encrypted data sequence (xci, Δ1i, Δ2i), but the high-quality data sequence (xbi, x2i
-1, xai, x2i) cannot be copied.

FIG. 8 is a block diagram showing a signal processing circuit of a decoder for realizing a second reference example of the code information copy protection method according to the present invention, and FIG. 9 is an S / N diagram of the signal processing circuit of FIG.
It is explanatory drawing which shows a ratio deterioration process. The encoder is the same as that of the first reference example, and the circuit shown in FIG. 8 is different only in the circuit for deteriorating the high-quality data sequence (xbi, x2i-1, xai, x2i). is there.

Here, in the DVD, the ID number is recorded together with the video and audio. Therefore, the ID number (AB... Z) and the character code "COPY" decoded by the DVD decoding circuit 42 are converted into, for example, an ASCII code by the pattern generator 58, and this is converted into noise and copy evidence data in FIG. As shown, the high-quality data string (xbi, x2i-1, xai, x2i) is replaced with the lower 8 bits and output as digital data.

Therefore, if the user copies and D / A-converts the data, the quality of the audio signal is degraded, so that it is possible to prevent the data from being copied with a high-quality quantization bit number, and the copyright holder By reproducing the recording medium and identifying the ASCII code, the side can detect whether or not the recording medium is a copy. Also, I
Instead of the D number, the current time data (data output time) of the clock 59 may be converted into, for example, an ASCII code, which may be used for deteriorating the quality of the audio signal and for determining the copy.

In the above reference example, the data string xci is A
The digital data that has been A / D converted by the / D converter 31 is band-limited and the sampling frequency is reduced to 1/4, and the difference data is calculated based on the data sequence xci. The data sequence xci is a data sequence in which the sampling frequency is reduced to し て by limiting the band of the digital data A / D converted by the A / D converter 31, and the difference data is calculated based on the data sequence xci. You may. In the above embodiment, the data string xci reduces the sampling frequency of the digital data A / D converted by the A / D converter 31 to 1/4. D
The interpolation data may not be calculated as a data string having the same sampling frequency as the converted digital data.

Next, a first embodiment will be described with reference to FIGS. FIG. 10 is a block diagram showing an encoder for realizing the first embodiment of the code information copy protection method according to the present invention, FIG. 11 is a block diagram showing the signal processing circuit of FIG. 10 in detail, and FIG. 12 is A of FIG. FIG. 13 is an explanatory diagram showing a sampling cycle and a data sequence of a / D converter. FIG. 13 is a block diagram showing a decoder for realizing a first embodiment of a code information copy protection method according to the present invention.
FIG. 14 is a block diagram showing the signal processing circuit of FIG. 13 in detail. The user data packed by the allocation circuit of FIG. 11 is the same as that shown in FIG.
The data sequence decoded by the decoder of FIG. 13 and the sampling period are the same as those shown in FIG.

In the encoder shown in FIG. 10, a copyright identification signal supply unit 100 is added to the configuration shown in FIG. 1, and the signal processing circuit 32 performs processing as shown in FIGS. First, similarly to the first and second embodiments, the analog signal input via the input terminal IN is A
A sufficiently high sampling frequency (sampling period Δ
t), for example, sampled at 192 kHz and converted into a high-resolution PCM signal of, for example, 24 bits, and
As shown in the figure, the data sequence (xbi, x2i-
1, xai, x2i).

This data sequence (xbi, x2i-1, xai, x2
i) is encoded by the signal processing circuit 32 and the memory 33 shown in detail in FIG. 11, and then this data is encoded by the DVD encoding circuit 34 together with the copyright data as the copyright identification signal from the copyright identification signal supply unit 100. Will be packed. This packing data is output from the output terminal OUT
1, or is modulated by the modulation circuit 35 in a modulation method according to the medium and output to the output terminal OUT2,
The information for identifying the copyright is output to the output terminal OUT3.
Is output to The output terminal OUT3 is also used as an input terminal when searching from an external device.

As shown in detail in FIGS. 11 and 12, in the signal processing circuit 32, the data string (xbi, x2i-1, xai, x2i) is first divided into 1/4 as in the first and second embodiments. Is divided into low bands by a low-pass filter 36 and down-sampled to a quarter band, and a low band signal (xci) in the band is extracted by a thinning circuit 37 and applied to an allocation circuit 40. Further, the data sequence (xbi, xai) is extracted by the thinning circuit 38,
The difference Δ1i xbi−xci = Δ1i is calculated by the subtracter 39 and applied to the allocation circuit 40.

In the first embodiment, the predictor 101 calculates the predicted value xdi 'of the curve β at the time of the sample (xai) of the curve α by using, for example, the quadratic prediction method. The difference Δ2i xai−xdi ′ = Δ2i between the predicted value xdi ′ and the actual sample value xai is calculated by 102 and applied to the allocation circuit 40. As shown in FIG. 4, the allocation circuit 40 packs these low-frequency components xci, the two types of prediction differences Δ2i and Δ1i, and the copyright identification signal in different channels in a predetermined arrangement, and the DVD encoding circuit 34 To supply.

Here, when one user data (packet) is 2034 bytes like a DVD, 334 low-frequency data xci are 3 bytes, and difference data Δ2i and Δ1i are 167 each having an average of 1.5 bytes each. And the subheader is allocated 33 bytes. Data from the copyright identification signal supply unit 100 is recorded in the subheader. For example, a disc serial number (16 bytes) which is information for managing a duplication state to identify a copyright; Code (4 bytes)-Recording date (3 bytes)-Number of recordings (3 bytes)-Number of copies (4 bytes) and-Number of copies (3 bytes) for managing copyright status are recorded. In addition to the sub-header on DVD,
The information for identifying the copyright is recorded in more detail in a copyright management information area (CMI area) provided on the inner periphery of the disc so as to correspond to a TOC area defined in a CDR disc or the like.

Next, the decoder will be described with reference to FIGS. In the decoder shown in FIG.
In place of the adder 56, the dither generator 57, and the digital output terminal 53 shown in FIG.
A digital output terminal 90 for adding copyright information to, for example, LSB of PCM data of (1, xai, x2i) and outputting the same is provided.

Referring to FIG. 14, the signal processing circuit 43 will be described.
bi = Δ1i + xci is calculated, xai = Δ2i + xdi ′ is calculated by the predictor 111 and the adder 112, and then xi is calculated by the interpolation processing circuit 47 based on the xai and xbi.
To calculate a high-quality data string (xbi, x2i-
1, xai, x2i). This data string (xbi, x2
i-1, xai, x2i) are output as analog signals via a D / A converter 45 and an analog output terminal 55. In the circuit shown in the lower stage, a high-quality data string (xbi, x2i) is output.
Digital data obtained by adding the copyright data (adder 118) to the multi-valued data of (-1, xai, x2i) is output via the digital output terminal 90.

More specifically, the copyright data reproduced from the subheader is, for example, 5 kHz from the oscillator 113.
It is modulated by an FM modulator 114 at a frequency of z, and the modulated signal is then spread widely to a low level by a spreading modulator 116 using a spreading code 115. Further, the Δ modulator 117
The data is converted to bits (192 kHz) and applied to the adder 118, and the adder 118 converts the high-quality data sequence (xbi,
After being added to the LSB of the data of (x2i-1, xai, x2i), the data is output as digital data.

Therefore, when outputting in the form of digital data, since the data includes copyright data, the copy state can be managed even when the data is copied, and as a result, unlimited copying is prevented. can do. Further, in this example, since the copyright data is transmitted through the medium, the decryption unit 50 decrypts the password and only the specific person copies the encrypted data string (xci, Δ1i, Δ2i). Since the copyright data is included, the copy state can be managed.

Next, a second embodiment will be described with reference to FIGS. FIG. 15 is a block diagram showing in detail a signal processing circuit of an encoder for realizing a second embodiment of the code information copy protection method according to the present invention. FIG. 16 is a block diagram showing the second embodiment of the code information copy protection method according to the present invention. FIG. 2 is a block diagram illustrating in detail a signal processing circuit of a decoder that realizes the embodiment. The second embodiment is a modification of the first embodiment, and FIGS. 15 and 16 correspond to FIGS. 11 and 14, respectively.

As shown in FIGS. 15 and 16, the copyright identification signal is modulated and the data sequence (xbi, x2i-1, xai, x2
Oscillator 113 for adding to i), FM modulator 11
4. Spreading modulator 116, Δ modulator 117, and adder 11
Reference numeral 8 is provided not on the decoder side but on the encoder side. That is, as shown in FIG. 15, the data obtained by adding the copyright data to the LSB of the multi-value data of the high-quality data sequence (xbi, x2i-1, xai, x2i) on the encoder side is transmitted to the low-pass of the signal processing circuit 32. The data is input to the filter 36, compressed, and transmitted.

Then, as shown in FIG. 16, on the decoder side, data obtained by adding the copyright data to the LSB of the multivalued data of the high-quality data string (xbi, x2i-1, xai, x2i) is output in a digital state. Enable and allow digital copying. That is, the copyright data is copied at the time of digital copying in the first embodiment and not copied at the time of analog copying, whereas the copyright data is copied at the time of digital copying or analog copying in the second embodiment.
When the decryption unit 50 decrypts the personal identification number and only the specific person copies the encrypted data string (xci, Δ1i, Δ2i), the copyright data recorded in the subheader of the recording medium is damaged or restricted. It can be copied intact without being interrupted or disturbed.

Next, a third embodiment will be described with reference to FIG. The third embodiment is a modification of the decoder of the first reference example shown in FIG. 5, in which a control unit 126 that responds to the copy number restriction information output from the decryption unit 50 is provided. Although the digital signal is output from the digital signal output terminal 53 when it exists,
The D / A converter 45 is disabled and an analog signal is controlled not to be output from the analog signal output terminal 55. This prevents analog data that does not include copyright data from being copied indefinitely.

FIG. 18 is a block diagram showing the fourth embodiment, which is a modification of the decoder of the first embodiment shown in FIG. The control unit 126 that responds to the copyright data in response to the copy number restriction information output from the decryption unit 50 disables the D / A converter 45 when the copy number restriction information exists, as in the fifth embodiment. The analog signal is controlled so as not to be output from the analog signal output terminal 55. Instead, the output signal of the signal processing circuit 43 is output via the digital signal output terminal 90, and a digital signal to which copyright data is added is output. This prevents analog data that does not include copyright data from being copied indefinitely. In the third embodiment and the fourth embodiment,
When the copy count restriction information exists, the operation of the D / A converter 45 is stopped. However, the present invention is not limited to this.
A switch can be provided before and after the converter 45 so that an analog signal is not output from the analog signal output terminal.

[0038]

As described above, according to the present invention, in particular, high-quality digital data is allowed to be copied in the state of digital data in which data indicating copyright is added. Convenience and copyright protection can both be achieved. In addition, if the digital signal is limited in the number of copies, the output is allowed only as a digital signal and the analog signal is not output, so that unlimited copying as an analog signal is effective. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first embodiment of a code information copy protection method according to the present invention.
FIG. 14 is a block diagram illustrating an encoder that realizes the reference example of FIG.

FIG. 2 is a block diagram illustrating a signal processing circuit of FIG. 1 in detail;

FIG. 3 is an explanatory diagram showing a sampling cycle and a data string of the A / D converter of FIG. 1;

FIG. 4 is an explanatory diagram showing user data packed by the allocation circuit of FIG. 1;

FIG. 5 is a diagram illustrating a first embodiment of a code information copy protection method according to the present invention.
FIG. 14 is a block diagram showing a decoder for realizing the reference example of FIG.

FIG. 6 is a block diagram showing the signal processing circuit of FIG. 5 in detail.

7 is an explanatory diagram showing a data string decoded by the decoder of FIG. 6 and a sampling period.

FIG. 8 is a diagram illustrating a second example of the code information copy protection method according to the invention.
FIG. 14 is a block diagram illustrating a signal processing circuit of a decoder that realizes the reference example of FIG.

9 is an explanatory diagram illustrating an S / N ratio deterioration process of the signal processing circuit of FIG. 8;

FIG. 10 is a block diagram illustrating an encoder that implements a first embodiment of a code information copy protection method according to the present invention.

11 is a block diagram illustrating the signal processing circuit of FIG. 10 in detail.

FIG. 12 is an explanatory diagram showing a sampling cycle and a data string of the A / D converter of FIG. 1;

FIG. 13 is a block diagram illustrating a decoder that realizes the first embodiment of the code information copy protection method according to the present invention.

FIG. 14 is a block diagram showing the signal processing circuit of FIG. 13 in detail.

FIG. 15 is a block diagram showing in detail a signal processing circuit of an encoder for realizing a second embodiment of the code information copy protection method according to the present invention.

FIG. 16 is a block diagram showing in detail a signal processing circuit of a decoder for realizing a second embodiment of the code information copy protection method according to the present invention.

FIG. 17 is a block diagram illustrating a decoder that realizes a third embodiment of the code information copy protection method according to the present invention.

FIG. 18 is a block diagram illustrating a decoder that realizes a fourth embodiment of the code information copy protection method according to the present invention.

[Explanation of symbols]

31 A / D converter (A / D conversion means) 32, 43 Signal processing circuit 33, 44 Memory 34 DVD encoding circuit 35 Modulation circuit 36 Low-pass filter 37, 38 Decimation circuit 39 Adder (difference calculation unit) 40 Allocation circuit ( Output means) 41 Demodulation circuit 42 DVD decoding circuit 45 D / A converter (D / A conversion means) 46 Adder (constituting restoration means together with interpolation processing circuit 47) 47 Interpolation processing circuit 49 Terminal 50 Decryption unit 51 Switch 52 , 53, 90 Digital output terminal 55, 132 Analog output terminal 56 Adder (dither generator 57, pattern generator 5
8, constituting S / N ratio deterioration means together with clock 59) 57 dither generator 58 pattern generator 59 clock 100 copyright identification signal supply unit 101, 111 predictor 102, 112 adder 113 oscillator (FM modulator 114 , The spreading code 115,
114 FM modulator 115 Spreading code 116 Spreading modulator 117 Δ modulator 118 Adder (adding means) 126 Control unit (Control means)

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Claims (13)

[Claims] 1. A / D conversion of an analog signal to generate first digital data, and transmitting second digital data obtained by adding copyright data related to the first digital data to the first digital data. Extracting the copyright data from the second digital data and modulating it; extracting the first digital data from the second digital data, converting the first digital data into an analog signal, and outputting the analog signal; Outputting the data only in the state of digital data obtained by adding the modulated copyright data to the first digital data. 2. A / D conversion of an analog signal to generate first digital data, and transmitting second digital data obtained by adding copyright data to the first digital data to the first digital data. Extracting the copyright data from the second digital data and modulating it; extracting the first digital data from the second digital data, converting the first digital data into an analog signal, and outputting the analog signal; Outputting the data only in the state of digital data obtained by adding the modulated copyright data to the first digital data; and when the copyright data is not accompanied by a copy number limit,
D / A converting and outputting only the second digital data for an analog signal; and outputting the second digital data when the copyright data is accompanied by a limitation on the number of copies. Controlling the signal so as not to D / A convert the second digital data or not to output the second digital data after the D / A conversion. 3. A / D conversion means for A / D converting an analog signal to generate first digital data, and a predetermined encoding in which copyright data relating to the first digital data is added to the first digital data. Output means for outputting second digital data in a format. 4. A code information decoding device for decoding first digital data generated by A / D conversion of an analog signal and second digital data to which copyright data related to the first digital data is added. D / A conversion means for extracting the first digital data from the second digital data and performing D / A conversion; and an analog for outputting an analog signal D / A converted by the D / A conversion means. A signal output terminal; a modulating means for extracting and modulating copyright data from the second digital data; an adding means for adding copyright data modulated by the modulating means to the first digital data; A digital signal output terminal for outputting the output of the adding means in the form of digital data, wherein the copyright data modulated by the modulating means is added. A decoding device for decoding the encoded information so as not to output the first digital data. 5. A code information decoding device for decoding first digital data generated by A / D converting an analog signal and second digital data to which copyright data relating to the first digital data is added. D / A conversion means for extracting the first digital data from the second digital data and performing D / A conversion; and an analog for outputting an analog signal D / A converted by the D / A conversion means. A signal output terminal; a modulating means for extracting and modulating copyright data from the second digital data; an adding means for adding the copyright data modulated by the modulating means to the first digital data; A digital signal output terminal for outputting the output of the adding means in the form of digital data, and when the copyright data is not accompanied by a copy number limit,
For an analog signal, only the second digital data is D / A-converted and output. On the other hand, when the copyright data is accompanied by a copy count limit, the output of the second digital data is permitted, For the signal, the second digital data is not D / A-converted or D / A-converted.
Control means for controlling not to output after the A-conversion; and decoding means for decoding code information, wherein the first digital data to which the copyright data modulated by the modulation means is not added is not output. 6. A recording medium in which digital data generated by A / D conversion of an analog signal is recorded as second digital data in a predetermined encoding format in which copyright data relating to the data is added. 7. A / D converting an analog signal to generate first digital data; modulating copyright data relating to the first digital data; and modulating the first digital data with the first digital data. Transmitting, via a medium, second digital data in a predetermined encoding format to which the added copyright data has been added; and converting and outputting the second digital data to an analog signal. 2. A method for preventing copying of code information which is output only in the state of digital data. 8. A / D converting an analog signal to generate first digital data; modulating copyright data relating to the first digital data; and modulating the first digital data with the first digital data. Transmitting, via a medium, second digital data in a predetermined encoding format to which the copyright data has been added, and when the copyright data is not accompanied by a copy number limit,
D / A converting and outputting only the second digital data for an analog signal; and outputting the second digital data when the copyright data is accompanied by a limitation on the number of copies. Controlling the signal so that the second digital data is not D / A converted or not output after the D / A conversion, and the digital data is output only in the state of the second digital data. And a method for preventing code information from being copied. 9. A / D conversion means for A / D converting an analog signal to generate first digital data; modulation means for modulating copyright data relating to the first digital data; Output means for outputting second digital data obtained by adding the copyright data modulated by the modulation means to the digital data. 10. An analog signal is subjected to A / D conversion to obtain a first signal.
Digital data is generated, and copyright data relating to the first digital data is modulated.
A decoding device for decoding code information for decoding the second digital data obtained by adding the modulated copyright data to the digital data, comprising: D / A conversion means for D / A converting the second digital data; An analog signal output terminal that outputs an analog signal that has been D / A converted by the D / A conversion means, and a digital output terminal that outputs the second digital data, wherein the modulated copyright data is A decoding device for code information configured to not output the first digital data not added. 11. An analog signal is subjected to A / D conversion to generate a first signal.
Digital data is generated, and copyright data relating to the first digital data is modulated.
A decoding device for decoding code information for decoding the second digital data obtained by adding the modulated copyright data to the digital data, comprising: D / A conversion means for D / A converting the second digital data; An analog signal output terminal that outputs an analog signal that has been D / A converted by the D / A conversion means; and a digital output terminal that outputs the second digital data, wherein the copyright data is not subject to a copy number limit. when,
For an analog signal, only the second digital data is D / A-converted and output. On the other hand, when the copyright data is accompanied by a copy count limit, the output of the second digital data is permitted, For the signal, the second digital data is not D / A-converted or D / A-converted.
Control means for controlling not to output after the A-conversion, and a decoding device for decoding code information configured to not output the first digital data to which the modulated copyright data is not added. 12. An analog signal is subjected to A / D conversion to generate a first signal.
Digital data is generated, and copyright data relating to the first digital data is modulated.
A recording medium on which is recorded the second digital data obtained by adding the modulated copyright data to the digital data. 13. The method according to claim 1, wherein the modulating step spreads copyright data in a spectrum.
7. A method for preventing code information from being copied according to any one of items 7 and 8.