JPH07334940A - Digital signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform a recording without consuming recording medium more than needed with an adequate error rate for a digital VTR at the time of recording a digital recording signal and to perform the recording with a satisfactory error rate at the time of recording data for controlling of a computer. CONSTITUTION:A digital video signal and a digital voice signal are processed as a recording signal in an AV signal processing part 34. Data for the control is processed as recording signal in a C signal processing part 35. The output of the C signal processing part 35 and the spreading code Css outputted from a spread code generating circuit 39 are multiplied by a multiplier 36 and then a spectrum is spread. Then, the signal is multiplexed with a recording AV signal by an adder 37 to be recorded on a magnetic tape 100 by a magnetic head 38. At the time of reproducing, time control data are reproduced by multiplying a regenerated reproducing signal by the same spread code Css as that by which the recording signal was multiplied before the recording.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital signal recording / reproducing apparatus such as a digital VTR or an external storage device of a computer.

[0002]

2. Description of the Related Art As an external storage device for a computer,
Magnetic disks and optical disks that are excellent in random access are often used. In recent years, so-called multimedia, in which a computer handles video signals and audio signals, has been receiving attention. Along with this, external storage devices are required to have larger capacity and lower cost than ever before. Particularly, storage of natural moving images requires a very large storage capacity. Therefore, when recording and reproducing a natural moving image on a magnetic disk or an optical disk, the storage capacity is insufficient. For this reason, it is necessary to compress moving image data using a high-efficiency coding method (for example, "home-use CD-ROM, TV top player that has been seen", Nikkei Electronics, 19).
1992 5-25 (No. 555), pages 103-121
page).

On the other hand, a tape device such as a digital video tape recorder (VTR) can have a very large storage capacity per volume as compared with a magnetic disk or an optical disk.
In particular, if a home digital VTR is commercialized, it will be a very large capacity and inexpensive digital signal storage device. Therefore, when the digital VTR is used as an external storage device for a computer, even when recording a natural moving image, it is possible to reduce the compression rate in the high-efficiency encoding and record it with good image quality or record a long-time moving image.

[0004]

By the way, when the above-mentioned conventional digital VTR is used as an external storage device,
There are the following problems. The digital VTR is constructed on the premise of recording a video signal. Therefore, in recording computer data, there is a problem that the error rate of reproduced data is generally low.

Digital video signals have a bit error rate of 10 ^-7.
If the following is not a visual problem (for example, "Next Generation VT
R is a digital record ”, Nikkei Electronics, 1988.
5-30 (No. 448), 111-137.
page). On the other hand, if there is an error in the data of the computer, the computer will perform an erroneous operation, so that a better error rate is required. Therefore, many hard disk devices guarantee a data error rate of 10 ^-9 or less (for example, "small HDD, recording density" G bit era "exposure", Nikkei Electronics, 9-30 1991).
(No. 537), pp. 77-106).

If data can be recorded with a high error rate in order to record computer data, the recording density per unit area decreases. Therefore, when recording a video signal, the recording medium is consumed more than necessary. Further, it becomes necessary to change the tape format as compared with the case of recording only video.

Therefore, the present invention has been made in order to solve such a problem, and a digital signal which allows a bad error rate and a digital signal which requires a good error rate are recorded on the same recording medium. It is an object of the present invention to provide a digital signal recording / reproducing device that records with a good error rate.

[0008]

According to the invention of claim 1 of the present application, a first digital recording signal and a second digital signal which is required to have a better error rate than the first digital input signal after recording and reproduction are provided. A digital signal recording / reproducing apparatus for recording / reproducing two systems of digital recording signals together with a recording signal, wherein a spreading code generating means for generating a spreading code having a data rate higher than that of a second digital recording signal; First multiplication of a digital recording signal and a spread code of a spread code generating means
Multiplying means, a multiplexing means for multiplexing the output of the first multiplying means and the first digital recording signal, a recording / reproducing means for recording and reproducing the output of the multiplexing means, and a reproduction signal from the recording / reproducing means. To reproduce the first digital recording signal
And a second multiplying means for multiplying the reproduced signal from the recording / reproducing means by the spread code of the spread code generating means,
A low pass filter for extracting a low frequency component of the output signal of the multiplying means, and a second determining means for determining the output signal of the low pass filter and reproducing the second digital recording signal. To do.

According to a second aspect of the present invention, there is provided a digital signal recording / reproducing apparatus which stores and reproduces at least one of a digital video signal and a digital audio signal and a program or control data of a computer. First encoding means for converting at least one of the signals into a first digital recording signal, second encoding means for converting computer program or control data into a second digital recording signal, and second digital A spreading code generating means for generating a spreading code having a data rate higher than that of the recording signal; a first multiplying means for multiplying the second digital recording signal by the spreading code of the spreading code generating means; and a first multiplying means. Multiplexing means for multiplexing the output and the first digital recording signal; recording / reproducing means for recording and reproducing the output of the multiplexing means; A first judging means for judging the reproduced signal from the recording / reproducing means to reproduce the first digital recording signal, and a second multiplying means for multiplying the reproduced signal from the recording / reproducing means by the spread code of the spread code generating means. And a low-pass filter for extracting a low-frequency component of the output signal of the second multiplication means, and a second determination means for determining the output signal of the low-pass filter and reproducing the second digital recording signal. It is characterized by that.

In the invention of claim 4 of the present application, the second encoding means includes a data rate of the second digital recording signal and a first digital recording signal.
The conversion is performed so that the data rate of the digital recording signal of (1) has an integer ratio relationship.

According to the invention of claim 5 of the present application, the second encoding means sets the data rate of the second digital recording signal to the first data rate.
Is set to a value lower than the data rate of the digital recording signal, and the spreading code generating means is characterized by generating a spreading code having the same data rate as the first digital recording signal.

According to the invention of claim 8, the spreading code of the spreading code generating means and the third multiplying means for multiplying the first digital signal by the first digital signal and outputting to the multiplexing means, and the spreading code of the spreading code generating means. And a fourth multiplying means for reproducing the first digital recording signal by multiplying the output signal of the first determining means with each other.

[0013]

According to the invention of claim 1 of the present application having such a feature, the second digital recording signal for which a good error rate is required is multiplied by the first multiplication means together with the spreading code,
The multiplication output and the first digital recording signal are multiplexed by the multiplexing means and recorded in the recording / reproducing means. Then, at the time of reproduction, the signal is read from the recording / reproducing means, and the first digital recording signal is reproduced by the first judging means. Further, the spread code of the spread code generating means is multiplied by the reproduced signal by the second multiplying means, and the second digital recording signal is reproduced from the low frequency component thereof.

According to the second aspect of the present invention, one of the digital video / audio signals and the computer program and control data are encoded into the first digital recording signal by the first and second encoding means, respectively. There is. Computer programs and control data are required to have better error rates than the first digital recording signal. For this reason, the frequency band is widened by spread spectrum using a spread code and recorded in the recording / reproducing means together with the first digital recording signal. At the time of reproduction, this reproduction signal is read and reproduced, the reproduction signal is multiplied by the spread code by the second multiplication means, and the second digital recording signal is reproduced from the low frequency component thereof. In this way, it is possible to apply the property of spread spectrum that only the intended signal can be collected in the low frequency band by using the spreading code, and the undesired signal (for example, noise) is not collected in the low frequency band. Therefore, when a digital video signal is recorded, it is recorded in a tape format that does not consume the recording medium more than necessary with a sufficient error rate as a digital VTR, and when recording computer data, the VTR tape is used. It is possible to record with a good error rate without changing the format.

Further, the invention of claim 4 of the present application is a means for reproducing the clock for judging each data by setting the data rate of the digital video signal and the audio signal to the data rate of the control data to be an integer ratio. It is intended to be shared.

Further, according to the invention of claim 5 of the present application, the reproduction equalization circuit can be shared by making the data rate of the spread code the same as the data rate of the digital video signal and audio signal to be recorded. Further, the phase of the code when the spread code is used on the data reproducing side of the computer can be determined by the synchronous reproducing circuit on the digital video signal and audio signal side.

Further, in the invention of claim 8 of the present application, when the video signal and the audio signal are recorded on the magnetic tape by using the scrambled NRZ modulation, the scrambling code string and the spreading code are shared by the same code. It was done.

[0018]

Embodiments of the digital signal recording / reproducing apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a digital signal recording / reproducing apparatus according to a first embodiment of the present invention, FIG. 1 (a) is a diagram showing an example of a configuration of a magnetic tape recording unit, and FIG. 1 (b) is a magnetic tape reproducing device. It is a figure which shows one structural example of a part.

In FIG. 1A, a digital video signal is input to the AV signal processing section 34 via the input terminal 31. In addition, the digital audio signal is transmitted via the input terminal 32 to the AV
It is input to the signal processing unit 34. The AV signal processing unit 34
The input digital video signal and digital audio signal are converted according to the tape format of the magnetic tape 100, and digitally recorded and modulated. If necessary, a blanking portion for multiplexing control data and recording it on the magnetic tape 100 is created. In the following description, the signal output from the AV signal processing unit 34 to the adder 37 is recorded AV.
Call it a signal.

On the other hand, the control data is input to the C signal processing section 35 via the input terminal 33. The C signal processing unit 35
The input control data is converted according to the tape format of the magnetic tape 100. The multiplier 36 multiplies the output signal of the C signal processing unit 35 and the spread code Css output from the spread code generation circuit 39. The output signal of the multiplier 36 is time-axis multiplexed with the recording AV signal by the adder 37,
Data is recorded on the magnetic tape 100 by the magnetic head 38.
Here, the recorded AV signal is the first digital signal, and the signal output from the C signal processing block 35 is the second digital recorded signal for which a better error rate is required.
Further, the multiplier 36 is a first multiplication means for multiplying the second digital recording signal and the spread code, and the adder 37 is a multiplexing means for multiplexing the output of the first multiplication means and the first digital recording signal. I am configuring. The AV signal processing section 34 is a first encoding means for converting at least one of a digital video signal and a digital audio signal into a first digital recording signal, and the C signal processing section 35 is a second encoding program or control data of a computer. It constitutes a second encoding means for converting into a digital recording signal.

In FIG. 1B, the signal recorded on the magnetic tape 100 is reproduced by the magnetic head 40.
The output signal of the magnetic head 40 is compensated for frequency deterioration due to magnetic recording / reproduction by the reproduction equalization circuit 41, and is input to the determination circuit 42 and the multiplier 44 which are the first determination means.

The reproduced digital signal judged by the judging circuit 42 is inputted to the AV signal processing section 43 and the synchronous reproducing circuit 51. The synchronous reproduction circuit 51 reproduces a timing signal such as a clock necessary for the subsequent processing from the input reproduced digital signal and outputs it to the AV signal processing unit 43 and the spread code generation circuit 52.

Based on the timing signal from the synchronous reproduction circuit 51, the AV signal processing unit 43 converts the input reproduced digital signal into the original digital video signal and outputs it to the output terminal. Output via 48. Similarly, when the input reproduced digital signal is the portion corresponding to the audio signal, it is converted to the original digital audio signal and output via the output terminal 49.

On the other hand, the spread code generating circuit 52 generates the same spread code Css as that multiplied before recording based on the timing signal from the synchronous reproducing circuit 51. Multiplier 44
Outputs the output signal of the reproduction equalization circuit 41 to the low pass filter (LPF) 45 by multiplying the spread code Css. LP
The F45 extracts only the low-frequency signal component from the output signal of the multiplier 44, and the determination circuit 46 serving as the second determination means.
Output to. The reproduced digital signal determined by the determination circuit 46 is input to the C signal processing unit 47. When the input reproduction digital signal is the portion corresponding to the control data, the C signal processing unit 47 converts the original reproduction data into the original control data and outputs the original control data via the output terminal 50.

As described above with reference to FIG. 1, the digital video signal and the digital audio signal are recorded on the magnetic tape 100. On the other hand, the control data is spectrally spread using the spreading code Css and recorded on the magnetic tape 100. As a result, in recording / reproducing on / from the magnetic tape 100, the control data is recorded with a better error rate than the video signal and the audio signal. This point will be described in detail below with reference to FIG.

FIG. 2 is a conceptual diagram showing the spectrum of each part of a signal recorded / reproduced on / from the magnetic tape 100 using the digital magnetic recording / reproducing apparatus of this embodiment. Here, the data rate of the digital video signal is 21.60 Mbit /
Second, the data rate of the digital audio signal is 0.77 Mbi
Therefore, it is assumed that signals of 22.37 Mbit / sec in total are input. When this is recorded, the recording signal becomes a bit stream of 22.37 Mbit / sec. The spectrum required to directly transmit this recording signal is the roll-off spectrum as shown in FIG.

In comparison with this, the transfer rate of the computer program and the data rate of the control data are generally low rates. Here, it is assumed that it is 5.6 Mbit / sec. It is considered that this control data is multiplied by a spread code Css and an M-sequence signal of 22.37 Mbit / sec, which is the same data rate as the digital video / audio recording signal. At this time, the spectrum required to transmit the original control data as it is may be a narrow band as shown in FIG. 2B, but it is required to transmit the signal after being multiplied by the spread code Css as it is. The spectrum is shown in Figure 2.
It has the same spectrum as shown in FIG. 2C, that is, the spectrum required for transmitting the video and audio signals shown in FIG. This is time-multiplexed with the video and audio recording signals and recorded.

In the magnetic tape reproducing section, the video and audio signals are reproduced at 70 Mbit / sec. This is a magnetic head 38 for recording a reproducing magnetic head 40.
This can be achieved by scanning at a tape head relative speed of 70 / 22.37 times that of the above. At this time, the magnetic head 40
2D, and the spectrum of the signal after being equalized by the reproduction equalization circuit 41 is as shown in FIG. Figure 2
In (d), the shaded portion shows the spectrum of noise added during recording and reproduction. The video signal and the audio signal have an error rate determined by the signal spectrum and the noise spectrum, and are determined as digital signals by the determination circuit 42.

On the other hand, in the multiplier 44, when the same code as the spreading code Css multiplied by the multiplier 36 on the recording side is multiplied in the same phase, the spread control data undergoes despreading, and FIG. The required signal power gathers at low frequencies like the spectrum shown in (). However, the noise spectrum is only whitened with the original noise power. Therefore, the LPF 45 extracts only the low-frequency components necessary for signal determination from this spectrum, so that the signal-to-noise ratio of the input signal of the determination circuit 46 (hereinafter referred to as SN
(Abbreviated as R) is improved by approximately 22.37 / 5.6 times as much as the SNR of the input signal of the decision circuit 42. As a result, the error rate of the control data output from the determination circuit 46 becomes better than the error rate of the digital video signal and the digital audio signal output from the determination circuit 42.

With the above configuration, when recording a digital video signal, a digital VTR is recorded in a tape format which does not consume the recording medium more than necessary with a sufficient error rate, and the control data of the computer is recorded. When recording, it is possible to record with a good error rate without changing the tape format of the VTR. An example for expressing this "computer control data" more accurately is shown in FIG.

FIG. 3 is a diagram showing a so-called interactive digital signal recording device constructed by using the first embodiment of the present invention, and FIG. 4 is a diagram showing a configuration of an interactive digital signal reproducing device. In FIG. 3, a digital VTR 1 is an interactive digital signal recording device 3
A digital video signal is input to the encoding circuit 10 in the interactive digital signal recording device 3 according to a command from a recording side central processing unit (CPU) 16 therein. The encoding circuit 10 encodes the input digital video signal with high efficiency to generate a digital compressed video signal in the magnetic tape recording unit 1.
Output to 7.

Here, the digital VTR 1 sets the luminance signal to 1
It is assumed that two color difference signals of 3.5 MHz are sampled at 6.25 MHz, and so-called 4: 2: 2 component digital video signals quantized with 8 bits are output. At this time, the data rate of the digital video signal output from the digital VTR 1 is about 216 Mbit / sec.

The encoding circuit 10 also encodes the input digital video signal with high efficiency to obtain 1/1 of the original data rate.
It is assumed that the digital compressed video signal of 21.6 Mbit / sec which is 0 is output to the magnetic tape recording unit 17. Such high-efficiency coding can be easily realized (for example, Okuda: "Application of image coding technology 5.V.
Coding Technology for TR ", Journal of Television Society, 45, 7
No., pp. 813-819 (1991)).

On the other hand, the digital audio recorder 2 also inputs a digital audio signal to the encoding circuit 11 in the interactive digital signal recording device 3 in accordance with a command from the recording side CPU 16 in the interactive digital signal recording device 3. The encoding circuit 11 highly efficiently encodes the input digital audio signal and outputs it to the magnetic tape recording unit 17 as a digital compressed audio signal.

It is assumed here that the digital audio recorder 2 samples a voice signal at 48 kHz and quantizes it at 20 bits and outputs it for four channels. At this time, the data rate of the digital audio signal output from the digital audio recorder 2 is about 3.8 Mbit / sec.

Further, the encoding circuit 11 highly efficiently encodes the input digital audio signal to obtain ⅕ of the original data rate.
It is assumed that the compressed digital audio signal of 0.77 Mbit / sec is output to the magnetic tape recording unit 17. Such high-efficiency coding can also be easily realized (for example, Takama: "Digital recording technology and its application 4-2 DCC (digital compact cassette)", Journal of Television Society, 47, 6). No., pp. 845-849 (1993)).

The control data generator 15 is necessary for the reproducing side central processing unit (CPU) 25 in the interactive digital signal reproducing apparatus 4 shown in FIG. 4 to control each section of the interactive digital signal reproducing apparatus 4. Generate various programs and data. The information amount of such programs and data is usually smaller than that of digital video signals. In this embodiment, this program and data are collectively controlled as 0.7 Mby.
at a data rate of te / sec, or 5.6 Mbit / sec,
It is assumed that the data is output from the control data generator 15.

The recording side CPU 16 uses the digital VTR 1,
Digital audio recorder 2 and control data generator 1
In addition to controlling the signal output from 5, the operation of each part of the interactive digital signal recording device 3 is controlled, and the digital video signal, the digital audio signal and the control data are recorded on the magnetic tape 100 in the interactive digital signal recording device 3. To do.

In FIG. 4, the magnetic tape reproducing section 21 in the interactive digital signal reproducing device 4 reproduces the magnetic tape 100 recorded by the interactive digital signal recording device 3 of FIG.

FIG. 5 shows a conceptual diagram of an example of software recorded and reproduced on the magnetic tape 100. FIG. 5 shows the passage of time from left to right, and the user of the interactive digital signal reproducing device 4 makes two selections during the reproduction of the software, so that the user comes to nine different endings. Shows a drama.

This software is reproduced from the "start screen" at the right end of FIG. 5, and the story 1 is first displayed by video and audio. When story 1 is over,
The selection screen 1 is displayed, and the user is made to select one of the following options (three options in FIG. 5) for story development, and the result is input from the operation input unit 26.

If the user selects an option following the story 2a, the interactive digital signal reproducing device 4 displays the story 2a by video and audio and then displays the selection screen 2a again to use the next option. A user selects and makes an input from the operation input unit 26. In this way, even if the story is the same at the beginning, a different ending will be reached depending on the selection of the user on the way.

When such software is reproduced by the interactive digital signal reproducing device 4 of FIG. 4,
The reproduction order of the video signal and the audio signal changes depending on the selection by the user. That is, the digital signals recorded on the magnetic tape 100 are not reproduced from the front in the order of recording,
It is reproduced from various positions on the magnetic tape 100 as required. Therefore, data for selecting and controlling the signal to be reproduced is required. This data is the control data generator 1
The control data is output from the No. 5 and recorded on the magnetic tape 100.

The software shown in FIG. 5 is used by the interactive digital signal recording device 3 to execute the magnetic tape 10
It is assumed that data is recorded in 0 as shown in FIG. That is, in order from the head position of the magnetic tape 100, overall control data, control data of block 1, digital compressed video signal and digital compressed audio signal of block 1, control data of block 2, digital compressed video signal and digital compressed audio of block 2 The signals, control data of block 3, digital compressed video signal of block 3 and digital compressed audio signal are arranged.

Returning to FIG. 4, when the magnetic tape 100 is reproduced, the entire control data is reproduced first, and the reproducing CPU 25
Entered in. The reproduction side CPU 25 selects and reproduces the signal recorded on the magnetic tape 100 based on the overall control data. In the present embodiment, next, the magnetic tape 1
The control data of block 1 is reproduced from 00, and the reproducing side C
It is input to the PU 25. Further, subsequently, the digital compressed video signal and the digital compressed audio signal of the block 1 are reproduced from the magnetic tape 100 and recorded in the first disk recording / reproducing unit 22 together with the control data of the block 1.

In the meantime, the reproduction side CPU 25 uses the overall control data to display the title of software, a description of usage, etc. through the signal multiplexing circuit 29 and the display 5 and the speaker 6.
Is displayed (output).

The digital compressed video signal and digital compressed audio signal of block 1 are transferred to the first disk recording / reproducing section 22.
When all of the data is recorded in, the reproduction side CPU 25 reproduces the digital compressed video signal and the digital compressed audio signal of block 1 from the first disc recording / reproducing unit 22 by using the control data of block 1 already input. It is input to the decoding circuits 27 and 28 via the signal selection circuit 24. Decoding circuits 27 and 28 decode the input digital compressed video signal and digital compressed audio signal into the digital video signal and digital audio signal of the original data rate, respectively, and display 5 and speaker via the signal multiplexing circuit 29, respectively. Output to 6. This state is the state in which the story 1 is displayed by video and audio in FIG.

At this time, in parallel with the reproduction of the story 1 from the first disc recording / reproducing section 22, the reproducing side CPU 25
Controls the magnetic tape reproducing section 21 to reproduce the control data of the block 2 and the digital compressed video signal and the digital compressed audio signal of the block 2 and record them in the second disk recording / reproducing section 23.

Here, the digital signal magnetic tape reproducing section 2 is used.
1 reproduction and the first disc recording / reproducing section 22 and the second disc
Writing to the disc recording / reproducing unit 23 is 70 Mbi.
It shall be performed at a data rate of t / sec. The reproduction of the digital signal from the first disc recording / reproducing unit 22 and the second disc recording / reproducing unit 23 is 22.4 Mbit /
It shall be done at a data rate of seconds. With this configuration, assuming that it takes 3 minutes for the first disc recording / reproducing unit 22 to reproduce the story 1, during that period, the second disc recording / reproducing unit 23 reproduces the stories 2a, 2b, 3 minutes, respectively. It is possible to record all the digital signals of 2c.

Therefore, when the entire story 1 is reproduced from the first disc recording / reproducing unit 22, the reproducing CPU
25 uses the control data of the block 1 that has already been input to create an image or sound for prompting the user to perform an operation, and displays it on the display 5 and the speaker 6. This is the state where the selection screen 1 is displayed in FIG.

Next, in response to the user's input from the operation input unit 26, the reproducing CPU 25 issues a command to the second disk recording / reproducing unit 23 to reproduce the necessary data from the control data of block 2. Input to the reproduction side CPU 25.
After that, the second disc recording / reproducing unit 23 reproduces the story selected by the user in the block 2 and outputs it to the display 5 and the speaker 6.

By repeating such an operation, the interactive digital signal reproducing apparatus 4 shown in FIG. 4 displays a video signal and an audio signal. When reproducing the software as shown in this embodiment, the digital video signal and the digital audio signal to be reproduced are changed by the input from the operation input unit 26. That is, the digital signals recorded on the magnetic tape 100 are not reproduced in the order in which they were recorded, but are reproduced from various positions on the tape as necessary. For this reason, if the signal reproduction from the magnetic tape 100 is output to the display 5 and the speaker 6 as it is, it is often necessary to fast-forward the tape during reproduction or rewind operation in more complicated software. Therefore, the video and audio will be interrupted.
In this embodiment, in order to enable continuous signal reproduction from the interactive digital signal reproduction device 4 without a gap, the first disc recording / reproducing unit 22 is used.
And the second disk recording / reproducing unit 23 is used.

In the digital signal recording / reproducing apparatus having the above-mentioned structure, when reproducing the digital video signal and the digital audio signal, even if a data error is included, if it is below a certain level, it is visually and auditorily. there is no problem.
For example, in the case of a video signal, if the bit error rate is 10 ^-7 or less, there is no visual problem. Furthermore, it is possible to perform error correction using the correlation of signals.

However, since the control data determines the operation of the reproducing side CPU 25, if an error occurs, the interactive digital signal reproducing apparatus 4 as a whole malfunctions. Therefore, even if recording / reproducing is performed on the same magnetic tape 100, it is necessary to reduce the error rate of the control data. Many hard disk devices used as external storage devices of computers guarantee a data error rate of 10 ⁻⁹ or less.

Here, it is assumed that the first disk recording / reproducing section 22 and the second disk recording / reproducing section 23 in the interactive digital signal reproducing apparatus 4 guarantee a data error rate of 10 ^-9 or less. . However, since the computer data is recorded in this way, if it is possible to record in a state with a good error rate, the recording density per unit area will decrease, and when recording video signals and audio signals, recording media will be stored more than necessary. It consumes.

However, in the first embodiment of the present invention, as described above, the magnetic tape recording unit 17 and the magnetic tape reproducing unit 2 are used.
In No. 1, when recording a digital video signal and a digital audio signal, the data is recorded by a tape format which does not consume the recording medium more than necessary with a visually and audibly sufficient error rate, and the computer data is recorded. When you do
It is possible to record with a good error rate without changing the tape format of the VTR.

The signal recorded / reproduced on the track end portion of the magnetic tape 100 is inferior in reliability to the signal recorded / reproduced on the track center portion of the tape. This is because the contact between the head and the tape is unstable because the head is close to the position where the head starts or ends contact with the tape during recording or reproduction. Therefore, in this embodiment, the reliability of the control data can be improved by setting the position where the control data is recorded to the center of the track. This point will be described in detail with reference to FIG. 7.

FIG. 7A is a diagram showing a configuration example of tracks on the magnetic tape 100. In this figure, signals are recorded on tracks formed obliquely to the longitudinal direction of the magnetic tape 100. Here, it is assumed that the head records a signal in the arrow direction from the lower end to the upper end of the tape.
When recording the control data, as shown in FIG. 7A, the tape (track) in which the contact between the head and the tape is stable
The reliability of the control data can be improved by recording in the central part of the.

In FIG. 7A, guard 1 and guard 2 are set between the control signal and the video signal. This is for taking a margin for editing when it is desired to edit only the control signal. In this portion, for example, an M-sequence signal, a square wave repetitive signal, or the like may be recorded. As a result, unnecessary recording signals are erased and at the guard portion, P
It is possible to prevent the LL from coming off.

FIG. 7B is a signal obtained by extracting the signal of the track recorded at the rightmost end in FIG. 7A. In the digital VTR, as shown in FIG. 7 (c), a signal is recorded by being divided into units called sync blocks. In each sync block,
A sync signal (hereinafter referred to as SYNC) for synchronizing in sync block units is added.

Therefore, when recording the control data, it is advisable to add SYNC, which is the same synchronization signal as the video signal, to the spread control data signal and divide it into sync block units for recording. Furthermore, guard 1 and guard 2 are also the same.
It is advisable to add the same SYNC as that of the video signal and divide the sync block unit for recording. By doing so, even when the control data is recorded, it can be recorded in the same tape format as the video signal. Therefore, there is also an advantage that the synchronization in sync block units is not disturbed between the video signal and the control data. It is not necessary to apply despreading to SYNC.

Further, as shown in FIG. 7B, it is preferable to record the spreading code as it is in the first sync block of the control data. This allows the reproducing apparatus to know what kind of spreading code was used during recording.

As described above, as in the present embodiment, the data rate of the spread code Css and the data rate of the recorded digital video signal and audio signal do not necessarily have to match, but if they do match, the reproduction is performed. A common one can be used as the equalization circuit 41. Further, the spread code Css is multiplied by the multiplier 44.
The signal phase at the time of inputting to can be determined by the synchronous reproduction circuit 51 on the digital video signal and audio signal side.

Further, since the recording signal has the same data rate for the digital video signal and the audio signal and the control data, it is not necessary to change the tape format when recording the control data as compared with the case where the tape format is used as the digital VTR. .

In other words, in a digital VTR that records only digital video signals and digital audio signals, some recording signals can be replaced with control data from a computer without changing the tape format. Moreover, in that case, the error rate in recording and reproducing the control data from the computer is better than the error rate of the original digital VTR.

As described above, the digital signal recording / reproducing apparatus of this embodiment has a digital VTR which can be constructed by excluding the portion for recording / reproducing control data from this embodiment, a mechanism for head scanning, a servo system, and recording. It is possible to share the PLL and the synchronization detection circuit for the synchronous reproduction of the signal to be reproduced.

Further, the video signal and the audio signal are converted into S-NRZ.
When recording on the magnetic tape 100 using modulation, it is also possible to share the scrambling code string and the spreading code Css with the same code. FIG. 8 is a block diagram showing a digital signal recording / reproducing apparatus for recording a signal to be scrambled by using S-NRZ modulation. In this figure, the same parts as those in the first embodiment described above are designated by the same reference numerals and detailed description thereof will be omitted. In this embodiment, the AV signal processing unit 3
4 is connected to the multiplier 61. The multiplier 61 multiplies the spread code Css from the spread code generation circuit 39 and the digital recording signal from the AV signal processing unit 34 and adds the product to the adder 37. The multiplier 61 constitutes third multiplication means for multiplying the spread code by the first digital signal. Further, in FIG. 8B, a multiplier 62 is provided on the output side of the decision circuit 42. The multiplier 62 multiplies the output signal from the determination circuit 42 by the spread code Css and outputs the output to the AV signal processing unit 43. This multiplier constitutes fourth multiplying means for multiplying the output signal of the first determining means by the spread code and reproducing the first digital recording signal.
By doing so, the data can be recorded on the magnetic tape by using the S-NRZ modulation, and the scrambling code string and the spreading code can be shared.

In the present embodiment, the digital VTR 1 is used as the reproducing / generating means of the digital video signal in FIG. 3, but it is not necessarily a digital VTR, and a computer graphics (CG) device, a digital output camera. And so on. Similarly, for the digital audio recorder 2, a digital VTR, a digital audio tape player (DAT), a compact disc player (CD), an electronic musical instrument or the like may be used.

In this embodiment, the data rate of the digital signal is specifically specified and explained, but it goes without saying that the present invention is not limited to this value. Furthermore, although S-NRZ is used as the digital recording modulation, other modulation methods can be used.

Although not described in the present embodiment, if the data rates of the digital video signal and audio signal and the data rate of the control data are set to be an integer ratio, the clock used in the determination circuit 42 is reproduced. PL for
The L and the PLL for reproducing the clock used in the determination circuit 46 can be shared.

As described above, the digital signal recording / reproducing apparatus of the first and second embodiments consumes the recording medium more than necessary with a sufficient error rate as the digital VTR when recording the digital video signal. VT is used when recording computer data in a tape format that does not
Recording can be performed with a good error rate without changing the R tape format.

[0072]

As described above, the claims 1 to 3 of the present application
According to the tenth aspect of the invention, the spread spectrum characteristic that only the intended signal can be collected in the low frequency band by using the spread code, and the undesired signal (for example, noise) is not collected in the low frequency band is obtained. When applied to recording, a digital recording / reproducing apparatus such as a digital VTR is used to record a digital video signal in a format that does not consume the recording medium more than necessary with a sufficient error rate. It is possible to provide a digital signal recording / reproducing apparatus for recording data with a good error rate without changing the format of VTR or the like.

Further, according to the invention of claim 4 of the present application, since the data rate of the digital video signal and the audio signal and the data rate of the control data are set to an integer ratio, the means for reproducing the clock at the time of judging the respective data. Can be shared, and the configuration can be simplified.

Further, in the invention of claim 5 of the present application, the reproduction equalization circuit can be shared by matching the data rate of the spread code with the data rates of the digital video signal and audio signal to be recorded. Further, the phase of the code when the spread code is used on the data reproducing side of the computer can be determined by the synchronous reproducing circuit on the digital video signal and audio signal side.

Further, according to the invention of claim 8 of the present application, when the video signal and the audio signal are recorded on the magnetic tape by using the scrambled NRZ modulation, the scrambling code string and the spreading code are shared by the same code. And the configuration can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a digital signal recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram showing spectrum of each part of a signal recorded / reproduced on / from the magnetic tape 100 using the digital magnetic recording / reproducing apparatus in the first embodiment of the present invention.

FIG. 3 is a block diagram showing an interactive digital signal recording device configured using the first embodiment of the present invention.

FIG. 4 is a block diagram showing an interactive digital signal reproducing device configured using the first embodiment of the present invention.

FIG. 5 is a conceptual diagram of an example of software recorded / reproduced on / from the magnetic tape 100 by the interactive digital signal recording / reproduction device configured by using the first embodiment of the present invention.

FIG. 6 is a conceptual diagram showing an example of a recorded state of the software shown in FIG. 5 on the magnetic tape 100 in the interactive digital signal recording / reproducing apparatus configured by using the first embodiment of the present invention.

7 is a diagram showing a configuration example of tracks on the magnetic tape 100. FIG.

FIG. 8 is a block diagram showing a configuration of a digital signal recording / reproducing apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Digital VTR 2 Digital Audio Recorder 3 Digital Signal Recording Device 4 Digital Signal Reproducing Device 5 Display 6 Speaker 10 Encoding Circuit 11 Encoding Circuit 15 Control Data Generation Unit 16 Recording Side Central Processing Unit (CPU) 17 Magnetic Tape Recording Unit 21 Magnetic Tape reproducing unit 22 First disc recording / reproducing unit 23 Second disc recording / reproducing unit 24 Signal selection circuit 25 Reproduction side central processing unit (CPU) 26 Operation input unit 27 Decoding circuit 28 Decoding circuit 29 Signal multiplexing circuit 31 Input Terminal 32 Input terminal 33 Input terminal 34 AV signal processing unit 35 C signal processing unit 36 Multiplier 37 Adder 38 Magnetic head 39 Spreading code generation circuit 40 Magnetic head 41 Reproduction equalization circuit 42 Judgment circuit 43 AV signal processing unit 44 Multiplier 45 LPF 46 Judgment circuit 47 C signal Signal processing unit 48 Output terminal 49 Output terminal 50 Output terminal 51 Synchronous reproduction circuit 52 Spread code generation circuit 61, 62 Multiplier 100 Magnetic tape

Claims (10)

[Claims] 1. A digital recording signal of two systems, that is, a first digital recording signal and a second digital recording signal that requires a better error rate than the first digital input signal after recording and reproducing are recorded. A digital signal recording / reproducing apparatus for reproducing, comprising: a spreading code generating means for generating a spreading code having a data rate higher than that of the second digital recording signal; and a second digital recording signal and the spreading code generating means. First multiplication means for multiplying a spread code; multiplexing means for multiplexing the output of the first multiplication means and the first digital recording signal; and recording / reproducing means for recording and reproducing the output of the multiplexing means. A first determination means for determining a reproduction signal from the recording / reproducing means to reproduce the first digital recording signal; and a reproduction signal from the recording / reproducing means for the spread code generating means. Second multiplying means for multiplying a spread code; a low-pass filter for extracting a low-frequency component of the output signal of the second multiplying means; and a second digital recording signal by judging an output signal of the low-pass filter. And a second determination means for reproducing the digital signal recording / reproducing apparatus. 2. A digital signal recording / reproducing apparatus for storing and reproducing at least one of a digital video signal and a digital audio signal and a program or control data of a computer, wherein at least one of the digital video signal and the digital audio signal is a first signal. A first encoding means for converting into one digital recording signal; a second encoding means for converting the computer program or control data into a second digital recording signal; and more than the second digital recording signal. Spreading code generating means for generating a spreading code having a high data rate, first multiplying means for multiplying the second digital recording signal by the spreading code of the spreading code generating means, and output of the first multiplying means And multiplexing means for multiplexing the first digital recording signal, and recording for recording and reproducing the output of the multiplexing means Reproducing means; first judging means for judging a reproduced signal from the recording / reproducing means to reproduce the first digital recording signal; and a spread code of the spreading code generating means for the reproduced signal from the recording / reproducing means. A low-pass filter for extracting a low-frequency component of the output signal of the second multiplying means, and a reproduction signal of the second digital recording signal by determining an output signal of the low-pass filter. And a second determining means for controlling the digital signal recording / reproducing apparatus. 3. The recording / reproducing means is magnetic recording / reproducing means using a tape-shaped recording medium, and the multiplexing means records a second digital recording signal in the central portion of the tape-shaped recording medium. 3. The digital signal recording / reproducing apparatus according to claim 1, wherein the digital signal recording / reproducing apparatus is multiplexed as described above. 4. The second encoding means performs conversion so that the data rate of the second digital recording signal and the data rate of the first digital recording signal have an integer ratio relationship. The digital signal recording / reproducing apparatus according to claim 2, wherein 5. The second encoding means sets the data rate of the second digital recording signal to a value lower than the data rate of the first digital recording signal, and the spreading code generating means. 3. The digital signal recording / reproducing apparatus according to claim 2, wherein the spreading code having the same data rate as that of the first digital recording signal is generated. 6. A digital signal recording apparatus according to claim 5, further comprising an equalizing means for equalizing a reproduced signal from said recording / reproducing means and outputting it to a first judging means and a second multiplying means. Playback device. 7. The digital reproducing apparatus according to claim 5, further comprising a synchronous reproducing means for generating a timing signal synchronized with the signal from the output signal from the first judging means and outputting the timing signal to the spread code generating means. Signal recording / reproducing device. 8. A third multiplication means for multiplying the spreading code of the spreading code generation means by a first digital signal and outputting the multiplied signal to the multiplexing means, a spreading code of the spreading code generation means, and a first multiplication means. 6. The digital signal recording / reproducing apparatus according to claim 5, further comprising: fourth multiplying means for reproducing the first digital recording signal by multiplying it with the output signal of the determining means. 9. The multiplexing means comprises a multiplexing means for multiplexing a common synchronization signal on the first digital recording signal and the second digital recording signal at a constant cycle. Digital signal recording / reproducing device. 10. The digital signal recording / reproducing according to claim 9, wherein a guard signal for one unit is inserted between the first digital recording signal and the second digital recording signal at the cycle of the synchronizing signal. apparatus.