JPH077574B2 - Recording / playback device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus such as a digital audio tape recorder (hereinafter referred to as DAT) capable of converting an analog signal into a digital signal for recording and reproducing. Is.

2. Description of the Related Art In recent years, standardization of interface specifications for connecting audio equipment with digital signals has progressed, and CD players, satellite broadcast receiving tuners (hereinafter referred to as BS tuners), etc. have digital output terminals in addition to analog output terminals. Have been commercialized. Also in the recording / reproducing apparatus, a recording / reproducing apparatus such as a DAT capable of directly recording a digital signal while converting an analog signal from a conventional audio device into a digital signal for recording has been put into practical use.

Hereinafter, a DAT will be described as an example of the recording / reproducing apparatus described above with reference to the drawings.

FIG. 3 is a connection diagram of a conventional audio device centering on a DAT, FIG. 4 is a part of a signal format of a digital audio interface, and FIG. 5 is a part of a recording format of a DAT.

In FIG. 3, 61 is a BS tuner, and 61A and 61D are BS tuners.
These are analog output terminals and digital output terminals of the tuner 61. 62 is a CD player, and 62A and 62D are analog output terminals and digital output terminals of the CD player 62. 63 is DAT
63A and 63D are analog output terminals and digital output terminals of the DAT 63. 64 is an analog audio device such as an FM tuner or an analog record player.
Is an analog output terminal of the analog audio device 64. 65 and 66 are DAT, 65B and 66B are DAT65 and DAT66
, Analog input terminals of 65C, 66C are digital input terminals of DAT65, DAT66, 65A, 66A are analog output terminals of DAT65, DAT66,
65D and 66D are digital output terminals of DAT65 and DAT66. DAT65 from the digital output terminals 61D, 62D, 63D and 65D of each device
Digital input terminal 65C and DAT 66 digital input terminal 66
Signals are transmitted to and received from C in a prescribed format as shown in FIG. As shown in FIG. 4 (a), two subframes of the left channel and the right channel are formed at the time of sampling the analog signal. Each sub-frame consists of 32 bits as shown in FIG. 4B, and is configured to transfer 20-bit audio data after 4-bit synchronization signal and 4-bit spare data. The channel status, which is 1 bit of the remaining 4 bits, is configured so that 192 bits are significant as one block as shown in FIG. 4 (c).
The 6 bits from bit 0 to bit 5 of the channel status are control bits, and indicate the purpose of data, availability of digital copying, and the like. That is, as shown in FIG. 4 (d), of the signal input to the digital input terminal 65C,
The second bit of the channel status, bit 2
When is “0”, DAT65 cannot record directly with digital signals (hereinafter referred to as digital copy). (For example,
(See Electronics Life Circular No. 655, pages 18 to 19, hereafter, when bit 2 of the channel status is "0", this bit 2 will be referred to as a copy prohibition bit.) Copyright is recognized as a compact disc. In general, a signal indicating that digital copying is prohibited is recorded on a compact disc, and when the compact disc is played back, a copy inhibition bit is output from the digital output terminal.
Since the signal from the digital output terminal 62D of the CD player 62 has a copy prohibition bit, the DAT 65 cannot record the signal on a recording tape (hereinafter referred to as tape).

In addition, DAT63, DAT65, and DAT66 tapes have a recording format as shown in FIG. 5, and have a main ID for reproducing PCM data in which audio signals are encoded and PCM data.
Is recorded in the PCM area in the center of the tape. The PCM area shown in FIG. 5 (a) consists of 128 blocks, and one block consists of 288 bits as shown in FIG. 5 (b). As shown in FIG. 5 (c), the main ID is repeatedly recorded every one block from the format ID, ID ₁ to ID ₆ , ID ₇ . As shown in FIG. 5 (d), the format ID 2
When the bit is "00", that is, when the DAT tape is recording audio data, the 2 bits of ID ₆ are "00"
When, the digital copy is possible, and when it is "10", the digital copy is prohibited. In other words, the tape recorded by the user of the DAT has ID ₆ of "00" and digital copying is possible, but in the case of a soft tape such as a music source, ID ₆
If you record "10" in, you cannot make digital copies.

However, the CD player 62 analog output terminal 62A to DAT65
The analog input terminal 65B of the DAT63 and the analog output terminal 63A of the DAT63 to the analog input terminal 65B of the DAT65 can be recorded (hereinafter referred to as analog copy). However, the control circuit 31 becomes possible. However, in this case, since it goes through the DA conversion circuit of the CD player 62 or the DA conversion circuit of the DAT 63 and the AD conversion circuit of the DAT 65, the sound quality may be slightly deteriorated as compared with the digital copy. Furthermore, since the ID ₆ shown in FIG. 5 (d) is "00" for the tape which has been analog-copied once, it is possible to endlessly perform digital copy from DAT65 to DAT66 without deterioration of sound quality.

Problems to be Solved by the Invention As described above, in the conventional DAT, although the freedom of recording for personal enjoyment is permitted, the compact disc has the digital copy prohibition in the digital signal. Since there is the signal shown, it is not possible to directly record the digital signal, which forces the DAT user to record with the analog signal, which slightly deteriorates the sound quality.

However, the ID _{6 of} the main ID is recorded as "00" in the DAT tape that has once been subjected to the analog copy control circuit 31, so that digital copying is possible indefinitely thereafter, and compact discs and DAT music soft tapes are analog. Although the sound quality is slightly deteriorated during copying, it is possible to make a duplicate product after that by digital copying without deterioration of the sound quality. for that reason,
It had a problem that it could bring huge disadvantage to the software industry such as music.

In view of the above problems, the present invention is an analog copy DAT.
The present invention provides a recording / reproducing apparatus such as a DAT that limits the number of generations of digital copy based on this tape that can be digitally copied.

Means for Solving the Problems In order to solve the above problems, the recording / reproducing apparatus of the present invention has a predetermined value at the time of analog copy, and the output digital signal when the recorded digital signal is reproduced next time is digitally copied. When a signal recorded on a recording medium is reproduced, a copy control signal generating section for obtaining a copy control subcode signal consisting of a plurality of bits indicating whether the digital copy is possible or not is determined by the presence or absence of a copy inhibition bit. When a category code setting section that outputs a category code or a second category code that enables digital copying regardless of the presence or absence of a copy prohibition bit and a copy control subcode signal having a predetermined value are reproduced A copy control signal discriminating unit for adding the copy prohibition bit and the second category code. Of.

Operation According to the present invention, when the analog copy first generation recording material is reproduced by the above-mentioned configuration, the digital output signal is added with the copy prohibition bit and the digital copy is performed regardless of the presence or absence of the copy prohibition bit. Since a possible second category code is added, this digital output signal can be input to the digital input terminal of another DAT to perform digital copying, and a second generation recorded matter can be obtained.
When the following second-generation recorded matter is reproduced, the copy prohibition bit is added to the digital output signal, and the presence or absence of the copy prohibition bit determines whether or not digital copying is possible.
Since it is configured to add the category code of
Subsequent digital copying is not possible. Therefore, the second generation can be duplicated by digital copying from the recorded matter obtained by analog copying the first generation, but the third generation cannot be duplicated by digital copying from the recorded matter of the second generation. You can limit the number.

Embodiment One embodiment of the present invention will be described below with reference to the drawings by taking a DAT as an example.

FIG. 1 is a block diagram of a DAT in one embodiment of the present invention. In FIG. 1, 1 is an analog input terminal and 2 is an AD
A converter 3 is a digital input terminal for demodulating a digital signal input to the digital input terminal 4 and a digital input decoder 4 is a selector switch for selecting whether the output signal of the AD converter 2 is an output signal of the digital input decoder 4, 6
Is a recording signal processing circuit that performs interleave processing for changing the temporal arrangement of digital signals, addition of error correction code, addition of an output signal of a subcode encoder 13 described later, and the like.
Reference numeral 7 is a recording amplifier, 8 is a recording head, and 9 is a magnetic tape. Reference numeral 10 denotes a copy inhibition bit determination unit that determines whether or not bit 2 of the channel status is "0" (presence / absence of copy inhibition bit). Reference numeral 11 indicates whether the category code shown in FIGS. 4 (c) and 4 (e) is the first category code (hereinafter, referred to as DAT category code) that determines whether digital copying is possible or not depending on the presence or absence of the copy inhibition bit, for example. Signal from the second category code (hereinafter referred to as DAT-C) for enabling digital copying regardless of the presence or absence of the copy inhibition bit, or a signal from a category other than DAT. It is a category code discrimination unit that discriminates whether the code is another code shown.

12 is obtained from the output signal of the copy prohibition bit discrimination unit 10 and the output signal of the category code discrimination unit 11 as the main ID ID ₆ shown in FIG.
In the case of analog copy, this is a copy control signal generator whose ID is "01". 13 is a subcode encoder that creates a subcode including ID ₆ . Reference numeral 14 denotes an operation switch including a recording switch, a reproduction switch, and an input selection switch for switching whether to record a signal input to the analog input terminal 1 or a signal input to the digital input terminal 3. An input setting unit that controls the selection switch 5 in accordance with the input changeover switch and controls ID ₆ to be "01" in the case of analog copy. 16, the copy prohibition bit determination unit 10 detects the copy prohibition bit,
This is a recording prohibition setting unit that controls the recording signal processing circuit 6 so as to prohibit recording when the category code determination unit 11 detects a DAT category code. 28 is a reproducing head, 17 is a reproducing amplifier, 18 is a reproducing signal processing circuit for performing error correction of digital signals and deinterleaving processing for restoring the temporal arrangement, 19 is a DA converter, 20 is an analog output terminal Is. 21 is a subcode decoder that obtains a signal such as a main ID, 22 is an ID output from the subcode decoder 21,
A copy control signal discriminating unit that outputs a command as shown in Table 2 to a copy prohibition bit setting unit 29 described later and a category code setting unit 30 described later.

Reference numeral 29 denotes a copy prohibition bit setting unit that sets bit 2 of the channel status to "0" when the copy control signal determination unit 22 outputs the copy prohibition bit existence, and "1" otherwise. Is. A category code setting unit 30 sets a corresponding 8-bit category code when "11000000" is output as DAT-C when the copy control signal determination unit 22 outputs DAT. Reference numeral 23 is a channel status encoder including the output signals of the copy prohibition bit setting unit 29 and the category code setting unit 30. 25 is an output signal of the reproduction signal processing circuit 18 and a channel status encoder 23
4 is a digital output encoder for obtaining the digital output signals shown in FIGS. 4 (a) and 4 (b) from the output signal of FIG. Reference numeral 27 denotes a system controller including a copy control signal generation unit, an input setting unit 15, a recording prohibition setting unit 16, a copy control signal discrimination unit 22, a copy prohibition bit setting unit 29, and a category code setting unit 30. For example, a microcomputer It is composed of.

The operation of the DAT configured as described above will be described below with reference to the drawings and tables. FIG. 2 is a flowchart showing a part of the processing of the system controller 27.

First, a case where a signal input from the analog input terminal 1 is recorded and this tape is digitally copied will be described.

When the input switch of the operation switch 14 is set to analog copy and the recording switch is pressed, the judgment step of FIG.
At 36, it is determined that the recording switch is pressed, and the process goes to a decision step 37. When it is determined in step 37 that analog copying is performed, in step 44, the signal input to the analog input terminal 1 and converted into a digital signal by the AD converter 2 is input to the selection switch. The input setting unit 15 controls the selection switch 5 to select the output of the AD converter, and in the processing step 45, outputs a control signal to the copy control signal generation unit 12 so that ID ₆ becomes “01”. Then in process step 53, the ID
_The subcode signal including ₆ and the output signal of the selection switch 5 are recorded on the timing tape 9 to perform analog copy.
The tape thus recorded is referred to as a first-generation tape.
When the second generation tape is made by digitally copying the first generation tape, when the reproduction switch in the reproduction side DAT operation switch 14 is pressed, the system controller 27 determines in step 46 that the reproduction switch is pressed. Recognizing that, the reproducing head 28 reproduces the signal recorded on the magnetic tape 9, and the digital signal of the audio signal is input to the DA converter 19 and the digital output encoder 25 via the reproducing amplifier 17 and the reproducing signal processing circuit 18. Then, the subcode signal is input to the copy control signal determination unit 22 via the subcode decoder 21.

Judgment step 47 of the system controller 27 of the reproducing DAT
In step S48, the copy control determination unit 22 determines that the ID ₆ is “01”, and in process step 48, outputs a command from the second table to the copy inhibition bit setting unit 29 to add the copy inhibition bit. In the determination step 49, the copy control signal determination section 22 causes the category code setting section 30 to display the DAT-
The command is output so that the category code corresponding to C is output. In processing step 50, the category code setting unit 30 outputs a command to the channel status encoder 23 to output an 8-bit category code indicating that digital copying is possible regardless of the presence or absence of the copy prohibition bit. The channel status encoder 23 obtains the signal shown in FIG. Subsequently, in processing step 54, the digital output decoder 25 outputs the output signals of the channel status encoder 23 and the reproduction signal processing circuit 18,
The digital signal shown in FIGS. 4A and 4B is obtained and output from the digital output terminal 26. When this signal is connected to the digital input terminal 3 of another DAT and digitally copied,
When the input selector switch of the operation switch 14 is set to digital recording and the recording switch is pressed, it is determined in decision step 37 that digital recording is set, and the process proceeds to step 38, where the input setting section 15 The selection switch 5 outputs the output signal of the digital input decoder 4 to the recording signal processing circuit 6
The recording controller DAT is set to input to the judgment step 39 of the system controller 27 of the recording side DAT. In the judgment step 39, the copy inhibition bit judgment unit 10 inputs the output signal of the digital input decoder 4 and checks the bit 2 of the channel status. Since bit 2 when the first generation tape is reproduced is a digital copy prohibition signal, that is, "0", it is judged that there is a copy prohibition bit, and the judgment step 40 is reached. In the judgment step 40, the category code judgment unit 11 inputs the output signal of the digital input decoder 4, checks bits 8 to 15 of the channel status, judges that it is DAT-C, and judges in processing step 42.
As shown in Table 1, ID ₆ is "1".
Set to 0 ". The tape thus digitally copied is the second generation tape. Similarly, when the second generation tape is digitally copied to make the third generation tape, the second generation tape is set. Reproduction, the copy control signal determination unit 22 determines that the ID ₆ is "10" and the processing step 48 is reached, and the copy inhibition bit setting unit 29 sets bit 2 of the channel status to "0". The command is output to the channel status encoder 23. Next, the determination step 49 is reached, and since the ID ₆ is “10”, the processing step 52 is reached and the category code setting unit 30 indicates to the channel status encoder that it is a DAT. A command is output to set the code to be "11000000." The channel status encoder 23 obtains the signal shown in Fig. 4 (c). The decoder 25 obtains the digital signal shown in FIGS. 4 (a) and 4 (b) from the output signals of the channel status encoder 23 and the reproduction signal processing circuit 18, and outputs it from the digital output terminal 26. Output from digital output terminal 26.
When a digital copy is made by connecting to the digital input terminal 3 of the DAT, in the decision step 39, the copy inhibition bit determination unit 10 determines that there is a copy inhibition bit, and in the determination step 40, the category code determination unit 11 is the DAT. Determine that. Here, if the channel status signal of the digital input signal includes a copy prohibition bit and the category code is DAT, digital copy is added, that is, the recording prohibition setting unit 16 prohibits recording in process step 41. In this way, if recording is prohibited by, for example, cutting off the signal output from the recording signal processing circuit 6 to the recording amplifier 7, the first generation is digitally copied from the analog copied tape to the second generation. Can be made, but it is not possible to make a digital copy from a second generation tape to make a third generation tape.

As described above, when a recorded material such as a first-generation tape that has been analog copied is reproduced, the digital output signal is
A copy prohibition bit is added, and digital copying is possible regardless of the presence or absence of the copy prohibition bit.
Since this category code is added, this digital output signal can be input to the digital input terminal of another DAT for digital copying, and a recorded material such as a second generation tape can be obtained. When the following second-generation recorded matter is reproduced, a copy prohibition bit is added to the digital output signal, and a first category code that determines whether digital copying is possible or not is determined by the presence or absence of the copy prohibition bit. Therefore, subsequent digital copy is not possible. Therefore, the second generation can be duplicated by digital copying from the recorded matter obtained by analog copying the first generation, but the third generation cannot be duplicated by digital copying from the recorded matter of the second generation. You can limit the number.

In the above-described embodiment, when the signal from the analog output terminal of the CD player or DAT is converted into a digital signal and analog copy is performed, that is, the reproduction device on the sending side is discriminated (whether reproduction is performed by the CD player or reproduction by the DAT. It was explained that limiting the number of copy generations for copyright protection when a signal that cannot be identified) is recorded on a DAT, but the analog signal was converted to a digital signal using an AD converter as an external device. , When the digital signal is directly input to the digital input terminal of the DAT and digitally copied, the copy inhibit bit is not added to the output signal of the AD converter in general. , And the subsequent digital copy is possible without limit,
Problems similar to analog copy occur. Therefore, even when digital copying is performed using an AD converter as an external device, if the copy control subcode signal is set in the same manner as the analog copying of the above-described embodiment, the number of generations of digital copying thereafter can be limited. it can.

As described above, according to the present invention, a copy control signal generating unit that generates a copy control subcode signal of a plurality of bits, which has a predetermined value at the time of analog copy and indicates whether or not reproduction signals can be copied, and a copy prohibition bit. A category code setting unit capable of outputting a first category code that determines whether digital copying is possible or not, or a second category code that enables digital copying regardless of the presence or absence of a copy prohibition bit, and a copy of the predetermined value. When the control sub-code signal is reproduced, a copy control signal discriminating unit for adding the copy prohibition bit and the second category code to the digital output signal is provided, so that the first generation is recorded as an analog copy. The second generation can be duplicated by digital copying, but from the second generation, the digitally copied third generation can be duplicated. The number of copy generations can be limited. Therefore, it does not bring any disadvantage to the software industry such as music.

[Brief description of drawings]

FIG. 1 is a block diagram of a DAT of an embodiment of the present invention, FIG. 2 is a flowchart showing a part of the processing of the system controller of FIG. 1, and FIG. 3 is a conventional audio device centering on a DAT. FIG. 4 is a block diagram showing a connection, FIG. 4 is a format diagram showing a main part of a signal format of a digital audio interface, and FIG. 5 is a format diagram showing a main part of a DAT recording format. 3 ... Digital input terminal, 10 ... Copy prohibition bit discrimination unit, 11 ... Category code discrimination unit, 12 ... Copy control signal generation unit, 13 ... Sub code encoder, 21 ... Sub code decoder, 22 ... Copy control signal discrimination section, 23 ... Channel status encoder, 26 ... Digital output terminal, 27 ... System controller, 29 ... Copy prohibition bit setting section, 30 ... Category code setting section.

Claims (1)

[Claims] 1. A predetermined value when an analog signal transmitted between a reproducing-recording device is converted into a digital signal and recorded, and an output digital signal when the recorded digital signal is reproduced next time is digital. When a signal recorded on a recording medium is reproduced, a copy control signal generator that obtains a copy control sub-code signal consisting of multiple bits indicating whether or not a signal can be directly copied is used. A category code setting section that outputs a first category code that determines whether or not to permit or outputs a second category code that enables digital copying regardless of the presence or absence of a copy prohibition bit, and a copy control subcode having a predetermined value To add the copy prohibition bit and the second category code to the digital output signal when the signal is reproduced Based on a recording medium created by converting the analog signal transmitted between the reproduction and recording equipment into a digital signal and recording the digital signal, the digital signal after that is provided with the copy control signal discrimination section. A recording / reproducing apparatus characterized in that the number of generations directly copied as it is is limited.