JP3024044B2 - Digital recording and playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital recording / reproducing apparatus, and more particularly, to an analog audio signal obtained by digital-to-analog conversion of a digital audio signal output from a digital audio source device because digital copying from the digital audio source device is prohibited. The present invention relates to a digital recording / reproducing apparatus suitable for digital recording based on a signal.

[0002]

2. Description of the Related Art There is a DAT that can input a digital audio signal from a digital audio source device and digitally record the digital audio signal as it is on a tape. However, some sources do not allow copying, in which case,
An analog audio signal obtained by D / A conversion of a digital audio signal output from a digital audio source device is input to a DAT, A / D converted into a digital audio signal by an A / D converter of the DAT, and digitally recorded on a tape. become. In this case, the analog audio signal output from the digital audio source device is not always at an optimum level with respect to the resolution (dynamic range) of the A / D converter. It is necessary to adjust the recording level by operating the provided recording volume for variable level.

[0003]

However, in the case of a DAT having no recording level meter, since the maximum level of the analog audio signal after the level adjustment is not known, the recording level is appropriately adjusted, and the A level is adjusted without saturating the peak. It is difficult to make effective use of the resolution of the / D converter to make a recording, so that the recording level is too low to reduce the dynamic range of the digital audio signal after A / D conversion, or, conversely, to record. There has been a problem that the level is set too high, causing peak saturation in the digital audio signal after A / D conversion. Also, since the DAT has a recording level meter, even if the maximum level of the analog audio signal after the level adjustment is known, if the user is unfamiliar with the recording level adjustment and makes an incorrect adjustment, the same problem occurs. Preliminary reproduction of the digital audio source device has to be performed, and there is a problem that it takes time and effort. SUMMARY OF THE INVENTION It is an object of the present invention to automatically adjust an analog audio signal output of a digital audio source device to an appropriate recording level so that digital recording can be performed.

[0004]

This onset Akira [Summary of] demodulates a digital audio interface signal input from the digital audio source device, and the digital signal input means for outputting a digital audio signal, an analog audio input from a digital audio source device A / D conversion means for A / D converting a signal, a digital audio signal output from a digital signal input means, and a digital audio signal output from the A / D conversion means for selectively selecting and outputting. Means for inhibiting copy in digital audio interface signal /
Determining means for determining permission information; and switching control means for switching the switching means to the digital signal input means when the determining means determines that copying is permitted and switching to the A / D converting means when determining that copying is prohibited. A digital recording / reproducing apparatus provided with a level varying means for varying the level of an analog audio signal, and comparing the digital audio signal output from the digital signal input means with the level of the digital audio signal output from the A / D conversion means. Comparing means, variable level control means for performing level variable control on the level variable means so that the comparison result by the comparing means becomes the same level when the determination means determines that copying is prohibited , prohibition / permission of level variable control Instruct
Operating means, and the level varying means is a manual
The level can be changed by operation, and
Level variable control means: Level variable control prohibited by operating means
Is indicated, the level for the level variable means
Level variable control permission is instructed by operating means without variable control
Variable level system for level variable means
Before performing control, memorize the level variable amount by the level variable means
After that, the level variable control for the level variable means is performed.
After the recording is completed, the level varying means is stored.
It is configured to return to a variable level .

[0005]

[0006]

According to the present onset bright, it may be provided a level varying means for varying the level of the analog audio signal, when the determination means has determined that the copy prohibition, the level variable control means has been output from the digital signal input means a digital Since the variable level control is performed on the level variable means so that the comparison result of the level of the audio signal and the level of the digital audio signal output from the A / D conversion means become the same level, the output from the A / D conversion means is performed. The dynamic range of the digital audio signal can be made the same as the digital output of the digital audio source device, and the recording level can be automatically and optimally adjusted without the user having to adjust the recording level. Also variable level
The means can be changed by manual operation
The control means is instructed by the operation means to prohibit variable level control.
Variable level control for level variable means when
User does not need to manually
The recording level can be set, and the level is variable
When control permission is instructed, the control means
Before performing variable level control on
The level variable amount in the stage is stored, and thereafter, the level variable means
Variable level control for
Means to return to the memorized level variable
Therefore, the user usually decides the level variable means
Recording with variable level, but temporarily variable level
Control and allow the recording level to be automatically adjusted for digital recording.
If sound is heard, after recording, change the level variable means to the original level
It saves the trouble of returning to the quantity.

[0007]

[0008]

FIG. 1 is a circuit diagram of a digital recording system according to one embodiment of the present invention. Reference numeral 1 denotes a CD player as an example of a digital audio source device, which reproduces a control code including a track number, an X indicating an index, a program time, a copy inhibition / permission code, and a 16-bit digital audio signal from a CD (not shown) during reproduction. It reads and outputs a digital audio signal and a digital audio interface signal including a predetermined control code from a D-OUT (digital out) terminal. At the same time, a digital audio signal read from a CD from an A-OUT (analog out) terminal is D / A. Output the converted analog audio signal. User data bits of control code of digital audio interface signal
The (U-bit) includes the track number, X indicating the index, and the program time, and the category code of the channel status bit (C-bit) includes the copy prohibition / permission code.

Reference numeral 2 denotes D as an example of a digital recording device.
The AT is a D-IN (digital in) terminal and a D-OUT (digital out) terminal of the CD player 1 are connected by a coaxial cable of 3, and an A-IN terminal (analog in) terminal and a CD A-OUT of player 1 (analog out)
The terminals are connected by a 4 pin code. Reference numeral 5 denotes a DAI (digital audio interface) circuit for demodulating and extracting the digital audio signal and control code when a digital audio interface signal is input to the D-IN terminal, and 6 for an analog audio signal input to the A-IN terminal. This is a recording volume as a level varying means for varying a level.
The level is varied according to the manual operation of A. 7 is a detection circuit for detecting a level variable amount by a recording volume,
Reference numeral 8 denotes an A / D converter for inputting an analog audio signal whose level has been changed by a recording volume 6 and performing A / D conversion to obtain a 16-bit digital audio signal. This is a comparison circuit for comparing the level of the digital audio signal output from the / D converter 8.

Reference numeral 10 denotes a DAI circuit 5 which is controlled by a controller.
A selector 11 for selectively selecting and outputting the digital audio signal extracted by the above and the digital audio signal output from the A / D converter 8. A signal processing circuit 11 is provided from the DAI circuit 5 via the selector 10. When a control code is input, a U-bit track number, an X indicating an index, a program time, and a C-bit category code are extracted and output to the controller. The digital audio signal is converted into a recording signal in which the input digital audio signal and a predetermined control code input from the controller are combined and output.

Reference numeral 12 denotes a recording head mounted on a rotating drum (not shown). Reference numeral 13 denotes an RF amplifier that amplifies a recording signal input from the signal processing circuit 11 and drives the recording head.
Reference numeral 4 denotes a servo circuit for performing servo control of a drum motor, capstan motor, and reel motor (not shown) based on a command from the controller. Reference numeral 15 denotes REC operation, STOP operation, automatic selection recording mode, digital input recording mode, and analog input recording mode. An operation / display panel 16 for performing various operations such as an operation for designating a type of recording mode, an instruction for prohibiting / permitting a variable level control for the recording volume 6, and a display indicating that a recording operation is being performed or digital copying is not possible;
Is a DAT tape as a recording medium.

Reference numeral 17 denotes a controller constituted by a microcomputer. When a recording mode is designated and a REC operation is performed on the operation / display panel 15, each section is controlled in accordance with the designated recording mode and input from the outside. The audio signal is digitally recorded on the DAT tape 16. At the start of recording, the controller 17 sets the analog input recording mode when the copy is prohibited as a result of determining the copy prohibition / permission code input from the signal processing circuit 11 because the automatic selection recording mode is designated. In the case of the analog input recording mode, the controller 17 inputs the current level variable amount in the recording volume 6 from the detection circuit 7 and stores it in the built-in memory (not shown) unless the level variable control inhibition is previously instructed. After that, until the comparison output of the comparison circuit 9 indicates that the digital audio signal output from the DAI circuit 5 and the digital audio signal output from the A / D converter 8 are at the same level.
The variable level control is performed on the recording volume 6, and after the analog input recording is completed, the level variable stored in the internal memory is read out, and the recording volume 6 is controlled to return to the original variable level.

Next, a method of digital recording from a CD to the DAT tape 16 will be described focusing on the operation of the controller 17. Designation of the automatic selection recording mode The automatic selection recording mode is designated on the operation / display panel 15 of the DAT 2, the level variable control is permitted, the REC operation is performed, and the PLAY operation is performed on the CD player 1.
When the reproduction of D is started, the CD player 1 outputs a digital audio signal and a digital audio interface signal including a predetermined control code from the D-OUT terminal, and simultaneously outputs an analog audio signal from the A-OUT terminal. The U-bit of the control code of the digital audio interface signal includes a track number, an X indicating an index, and a program time, and the C-bit category code includes a copy prohibition / permission code. The DAT circuit 5 of the DAT 2 demodulates the digital audio interface signal, extracts the digital audio signal and the control code, outputs the digital audio signal and the control code to the selector 10, and outputs the digital audio signal to the comparison circuit 9. On the other hand, after the level of the analog audio signal input to the A-IN terminal is
The signal is converted into a digital audio signal by the / D converter 8 and output to the selector 10. The current level variable amount of the recording volume 6 is detected by the detection circuit 7 and the controller 1
7 is output.

When the REC operation is performed, the controller 17 first switches the selector 10 to the DAI circuit 5 side to input a control code in the digital audio interface signal to the signal processing circuit 11, and the signal processing circuit 11 extracts the control code. Enter the C-bit category code you entered. Then, it is determined whether or not digital copy is prohibited by the copy prohibition / permission code in the category code. If digital copy is prohibited, the mode is set to the analog input recording mode, and the selector 10 is set to the A / D converter 8 side. After switching, a recording operation command is given to each part to perform a recording operation. Subsequently, since the level variable control is permitted before the REC operation, the controller 17 inputs the current level variable amount in the recording volume 6 from the detection circuit 7 and stores it in the built-in memory. Level control is performed on the recording volume 6 until the output indicates that the digital audio signal output from the DAI circuit 5 and the digital audio signal output from the A / D converter 8 are at the same level. As a result, the digital audio signal output from the A / D converter 8 has the same dynamic range as the digital audio signal output from the DAI circuit 5, and the resolution of the A / D converter 8 is effectively used. be able to.

The signal processing circuit 11 which has started the recording operation converts the digital audio signal input from the A / D converter 8 via the selector 10 and the control code input from the controller 17 into a predetermined recording signal, and converts the signal into an RF signal. Output to the amplifier 13. The RF amplifier 13 amplifies the recording signal and drives the recording head 12. As a result, in the analog input recording mode, even if the user does not adjust the variable level of the recording volume 6 by turning the knob 6A before the start of recording, the dynamic range is automatically increased without causing peak saturation. Can be recorded on the DAT tape 16.

At the end of the reproduction of the CD, a STOP
When operated, the controller 17 controls each part to stop the recording operation and complete the analog input recording. And
The variable level stored in the internal memory is read out, and the recording volume 6 is controlled to return to the original variable level. As a result, the user normally prohibits the variable level control and sets the recording volume 6 to a certain fixed variable amount while recording, but the recording level is automatically set without temporarily prohibiting the variable level control. When the digital recording is performed with the adjustment, the trouble of returning the level varying means to the original level varying amount after the recording can be omitted.

On the other hand, when the controller 17 checks the copy prohibition / permission code in accordance with the designation of the automatic selection recording mode, if digital copying is possible, the digital input recording mode is set and the selector 10 is set to the DAI circuit 5 side. The recording operation command is given to each section while the recording mode is changed over to the recording operation. In the digital input recording mode, the controller 17 does not perform the level variable control on the recording volume 6 including the storage and the return control of the level variable amount. However, based on the control code input from the DAI circuit 5 by the signal processing circuit 11, the U-bit track number, X,
Since the program time and the like are extracted and output to the controller 17, a predetermined control code including these data is output to the signal processing circuit 11, and the signal processing circuit 11 outputs the digital audio signal input from the DAI circuit 5 through the selector 10. The signal and the control code input from the controller 17 are combined to convert the signal into a predetermined recording signal, which is output to the RF amplifier 13. Thus, a digital copy from the CD to the DAT2 is made.

If the user instructs the operation / display panel 15 to prohibit the variable level control before performing the REC operation, the controller 17 performs the analog input recording because the copy is prohibited by the copy prohibition / permission code. Mode, switch the selector 10 to the A / D converter 8 side,
Even when a recording operation command is given to each unit to perform a recording operation, the level variable control for the recording volume 6 is not performed including the storage and return control of the level variable amount. At this time, the user can freely adjust the recording level by turning the knob 6A to arbitrarily change the level variable amount of the recording volume 6.

[0019] when the REC operation on the operation / display panel 15 of the specified digital input recording mode DAT2 specify a digital input recording mode, the controller 17 switches the selector 10 to the side of the DAI circuit 5,
The copy prohibition / permission code input from the signal processing circuit 11 is checked, and if copying is permitted, the digital input recording mode is set, and a recording operation command is issued to each unit while the selector 10 is switched to the DAI circuit 5 side. Give recording operation. In the digital input recording mode, the controller 17 does not perform variable level control on the recording volume 6. However, if copying is prohibited,
The digital input recording mode is not set, and a message indicating that digital copying is prohibited is displayed on the operation / display panel 15.

Specifying the analog input recording mode As a result of specifying the digital input recording mode, digital copying is prohibited. Therefore, when the analog input recording mode is specified again on the operation / display panel 15 of the DAT 2 and the REC operation is performed, the controller 17 is operated. In the automatic selection recording mode described above, as a result of checking the copy prohibition / permission code, the same processing as when the copy is prohibited is performed. Therefore, if the user has previously permitted the variable level control, a digital audio signal having the same dynamic range as the digital audio signal output from the DAI circuit 5 is recorded on the DAT tape 16, and after the recording is completed, the recording volume 6 The variable level at is automatically restored. If the user previously instructs the prohibition of the variable level control, the controller 17 does not perform the variable level control on the input of the A / D converter.

According to this embodiment, when recording on the DAT tape 16 in the analog input recording mode, if the user instructs in advance the prohibition of the variable level control, the knob 6A is used.
By turning, digital recording can be performed at a desired recording level. Also, when the recording level of the CD is large and the resolution of the A / D converter 8 is to be used effectively,
If the level variable control has been permitted in advance, the controller 17 can control the A / D converter 8 based on the comparison output of the comparison circuit 9.
The level of the recording volume 6 is controlled so that the level of the digital audio signal output from the DAI circuit 5 becomes the same as the level of the digital audio signal output from the DAI circuit 5, so that the user does not need to manually adjust the recording level. A digital audio signal having the same dynamic range as the digital audio signal automatically output from the DAI circuit
And the resolution of the A / D converter 8 can be used effectively. Then, when the analog input recording is completed, the controller 17 automatically returns the recording volume 6 to the level variable amount before the level variable control, so that the user usually records with a certain fixed level variable amount. In the case, the recording volume 6 by manual operation
Need not be restored to the original state.

[0022] Further, if the user has a CD player 1 and a DAT 2
Is connected to the coaxial cable 3 with the pin code 4 and the CD player 1 performs the reproducing operation, and the DAT 2 specifies the automatic selection recording mode and performs the recording operation.
Automatically determines whether or not copying of the CD is prohibited. When prohibited, the digital recording is performed based on the analog input. When the copying is permitted, the digital recording is performed based on the digital input. The user can check whether or not copying is prohibited. When the copying is prohibited, the user can save the trouble of instructing analog input recording and, when permitted, instructing digital input recording.

In the above-described embodiment, the D-OUT terminal of the CD player 1 and the D-IN terminal of the DAT 2 are connected by the coaxial cable 3, but if both are provided with optical connectors, an optical fiber cable is used. May be used to transmit and receive digital audio interface signals. Digital audio sources are DAT, DCC,
Various devices such as a mini disk, a CD-PC, a BS tuner, and the like can be used, and various digital recording devices other than the DAT, such as a CD-R recording device and a mini disk system, can be used.

[0024]

According to the onset light according to the present invention, it may be provided a level varying means for varying the level of the analog audio signal, when the determination means has determined that the copy prohibition, the level variable control means is output from the digital signal input means The level variable control is performed on the level variable means so that the comparison result of the level of the digital audio signal and the level of the digital audio signal output from the A / D converter becomes the same level. The dynamic range of the output digital audio signal can be made the same as the digital output of the digital audio source device, and the recording level can be automatically and optimally adjusted without the user performing the operation of adjusting the recording level. Also,
The bell variable means can change the level by manual operation
Control means, the level variable control prohibition
When indicated, the level for the variable level means
No manual control by the user when desired
To set the desired recording level.
When permission for variable control is instructed, the control means
Before performing variable level control on the bell variable means
The variable level of the variable means is stored.
Performs variable level control for variable means,
The variable level means is restored to the stored level variable amount.
As a result, the user usually decides to change the level
Although recording was performed with a variable level,
Allow variable control to automatically adjust the recording level and
If you have recorded the sound level, use the variable level
The trouble of returning to the variable amount can be saved.

[0025]

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a digital recording system according to one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 CD player 2 DAT 3 Coaxial cable 4 Pin code 5 DAI circuit 6 Recording volume 7 Detecting circuit 8 A / D converter 9 Comparison circuit 10 Selector 11 Signal processing circuit 12 Recording head 13 RF amplifier 14 Servo circuit 15 Operation / display panel 16 DAT tape 17 controller

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Seiichi Ito 1-2-5 Shibuya, Shibuya-ku, Tokyo Inside Kenwood Corporation (72) Inventor Koji Okawara 1-2-5 Shibuya, Shibuya-ku, Tokyo Kenwood Corporation (72) Inventor Tetsuro Kino 1-2-5 Shibuya, Shibuya-ku, Tokyo Inside Kenwood Co., Ltd. (72) Inventor Hiroyuki Suzuki 1-2-5 Shibuya, Shibuya-ku, Tokyo Kenwood Co., Ltd. (56) References JP-A-3-125375 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 20/10

Claims (1)

(57) [Claims] 1. A digital signal input means for demodulating a digital audio interface signal input from a digital audio source device and outputting a digital audio signal, and an A / D converter for A / D converting an analog audio signal input from the digital audio source device.
D conversion means, switching means for selectively selecting and outputting a digital audio signal output from the digital signal input means and a digital audio signal output from the A / D conversion means, and the digital audio interface Determining means for determining copy prohibition / permission information in a signal, and switching means for switching to digital signal input means when the determination means determines that copying is permitted;
A digital recording / reproducing apparatus having a switching control means for switching to an A / D conversion means when it is determined that copying is prohibited; a level varying means for varying a level of an analog audio signal; Comparing means for comparing the level of the digital audio signal with the level of the digital audio signal output from the A / D converting means; and when the determining means determines that copying is prohibited, the result of comparison by the comparing means becomes the same level. A variable level control means for performing variable level control on the level variable means, and an operation means for instructing prohibition / permission of the variable level control , wherein the level variable means can vary the level even by manual operation.
And the level variable control means is provided with a level variable control by an operation means.
When prohibition is instructed, the level
Level variable control is enabled by operating means without performing bell variable control.
When indicated, the level for the variable level means
Before performing variable control, record the level variable amount with the level variable means.
Remember, after this, variable level control for level variable means
After the recording is completed, the level varying means is stored.
A digital recording / reproducing apparatus, wherein the digital recording / reproducing apparatus is configured to return to a variable level .