JPS60201572A - Multi-channel recorder - Google Patents

Abstract

PURPOSE:To realize major components with identical constitution without giving any change in frequency by recording and reproducing a signal from 2-channel to n-channel (n=2<k>) while having only to switch A/D, D/A conversion and their interface. CONSTITUTION:An N-channel input analog signal is inputted from terminals 1(1), 1(2),...1(N) and converted into a digital code by A/D converters 2(1), 2(2),...2(N). A compression memory 3 applies compression multiplex a sample data converted into a digital code into 1/N time axis. The data subject to compression multiplex is recorded on an optical disc 15 having a concentric recording track so that the same channel is arranged radially and when it is reproduced, it is converted into an analog sound signal by a decoder 23 of multiplexed data format, an expanding memory 25 expanding the multiplexed data to the original time axis and N-set of D/A convertes 26.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical disc device for recording and reproducing digital audio signals of a plurality of channels.

2. Description of the Related Art Structures and Their Problems In recent years, the development of devices for optically recording and reproducing signals on a disk-shaped record carrier generally called an optical disk has become active. A device that records and reproduces information by applying a change in the shape of irregularities on the order of microns, an optical density change, or a magneto-optical change to a record carrier.
Various types have been developed as technology advances, including types that allow playback, recording, playback, and erasing.

On the other hand, as devices that can digitally encode and record and play back audio signals, there are DADs (Digital ψ Audio Discs), including digital audio tape recorders using magnetic tape and playback-only CDs (compact discs) using disks. exists. In general, tape recorders have the advantage of being capable of long-time, multi-channel recording and playback compared to disk-type recorders, but are inferior in terms of high-speed access and editing performance. Digital audio tape recorders currently in practical use range from 2-channel stereo type to 16-32 channel multi-channel type, each using tapes of different widths.
This is achieved by changing the tape speed or by changing the number of tracks used per channel. In the multi-channel type used for professional purposes such as studios, each channel can be recorded and played back as desired, and editing functions such as assembling, inserting, dubbing, etc. are essential between each channel. In the case of business applications such as studios and broadcasting stations mentioned above, since editing and dubbing operations are frequently used, if multiple channels can be recorded for a long time and the functions of a conventional tape recorder can be realized, high-speed random access will be possible. A disk type is more suitable than a tape recorder because of its superior performance and the possibility of reducing the volume of the recording medium.

2. Description of the Related Art Conventionally, there is an example of a disk recorder that stores digitized acoustic signals as data in a magnetic disk device used as a file device for computers and the like, and has excellent high-speed access. In this case, several hundred MB (megabytes)
Even if a high-capacity magnetic disk drive is used, the recording time is approximately 46 minutes for two channels at most, and if the number of channels is doubled, the recording time is approximately halved. This is because the recordable area of a magnetic disk device is much smaller than that of a tape, and if the only purpose is to store audio signals, the redundancy of the magnetic disk device is increased due to the fact that it contains information that is unnecessary for recording audio signals. . Furthermore, magnetic disk drives are large and expensive, and have many complicated and unnecessary parts for the sole purpose of storing audio signals.

On the other hand, a recordable type called an optical disk can record at a much higher track density than a magnetic disk. Furthermore, high-speed access is possible on the order of several hundred m5ec, although it is not as fast as that of magnetic disks. Currently, these optical discs are D RAW (Dire
The development of large-capacity document file devices and cheetah file devices for computers is progressing, including types called ct Read Afte Write) types that allow additional recording and types that can be erased.

OBJECTS OF THE INVENTION An object of the present invention is to provide a recording format for realizing a device capable of recording and reproducing multiple channels of audio signals using an optical disc capable of high-density recording.

Structure of the Invention The present invention provides a method for digitally encoding a maximum of N channels of audio signals and recording and reproducing them. recording on an optical disk having concentric recording trunks so that the same channels are aligned radially, by a recording means comprising means for dividing a compressed and multiplexed data string into N groups for each channel and configuring a format; For playback, a means for detecting the playback signal from the disk and decoding the multiplexed cheetah manode, a means for expanding the multiplexed data to the original time axis, and N D/ This is a recording and reproducing device that has a reproducing means consisting of a means for converting into an analog audio signal with an A converter, and is configured according to the number of recording channels so that recording and reproducing of the audio signal of the N2H channel can also be realized with compatibility. It has a means for changing the transfer speed in the trunk width direction, and has a format configuration in which each channel is separated, so that access to each channel can be realized as desired.

Furthermore, multiple optical heads are arranged to quickly implement the editing functions required for a multi-channel recorder.

Description of examples Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a recording/reproducing apparatus according to an embodiment of the present invention. In the figure, 1 (1), ..., 1 (N) are analog audio signal input terminals, 2 (1), ..., 2 (N) are A
/D converter, 3 is compression memory, 4 is data node, 5
is a multiplier for cross-fade processing, 6 and 6' are 1
Consists of two memories with the capacity of a trunk) (sofa memory, 7 is an interleap memory that scrambles the time series of data samples, 8 is an error correction code (KCC) generation circuit, 9 is a control code generation circuit, 1o is an error A shortened cyclic code (cRcc) generation circuit for detection, 11 a modulation circuit, 12 an ampoule 5 for adding a preamble, a postamble, and a block synchronization signal (SYNC).
A YNC addition circuit, 13 a recording amplifier that drives a laser with a recording signal, and 14 a recording and reproducing device on a disk.

An optical head performs erasing, 15 is an optical disk as a recording medium, 16 is an actuator for the optical head 14 that accesses the disk in the radial direction, and 17 is a playback device that amplifies and shapes the playback signal detected by the optical head 1)4. knob, 1
8 is a demodulation circuit, 19 is a TBC (time pace corrector) that absorbs jitter components included in the reproduced signal and performs time axis correction, 2o is a CRCC detection circuit, and 21 is a data and an error correction circuit that corrects errors in the control code using an ECC (error correction code); 22 is a deinterleave memory that returns scrambled data to the original time sequence; 23 is a control decoder that decodes the control code signal;
24 is an average value interpolation circuit that corrects uncorrectable error data by average value interpolation, 25 is an expansion memory paired with the compression memory 3, and 26(1), . . . , 26(N) are D
/A converter, 27(1).

..., 27 (tJ) is an analog signal output terminal, and 28 is a CPU (central processing unit) that controls the operation of the recording/reproducing apparatus.

FIG. 2 is a diagram showing the state of formation of recording tracks on a disk, which is a recording medium, and shows concentric recording tracks, track 0, ... track j1 ... track M, arranged in the radial direction N.
Each divided area is called a sector. This sector is sector 0,..., sector i,...
Let it be sector (N-1).

FIG. 3 is a diagram showing the format of a recording signal of one sector, and each sector is separated by a preamble and a postamble. Ampoule bits for each channel (each sector)
Since it is recorded arbitrarily, it is used for guard space considering jitter margin when turning on/off the recording mode and for clock recovery pull-in during playback. One sector consists of a control block and n data blocks.
At the beginning of each program is a block synchronization signal (SYNG).
is provided. The control block consists of a block synchronization signal (SYNC), a control code, ECC (error correction code), and 0RCG (error detection code).The control code data may include various types of information as shown in the figure. It will be done. Entire sector information can be erased starting from the beginning.

Code indicating no, address code for each sector.

Format identification information (formant II) indicating how many channels were recorded in 2-channel to N-channel mode 1, channel number indicating which channel the sector corresponds to, disc number, and other IDs. Information (recording date, instrument part name,
Player names, nine song titles, indexes, etc.) can be recorded.

The Cheetah block uses the block synchronization signal (SYNC), A
/D converted sample data group, error correction code (F
CC).

It consists of error detection code (CRCC).

Next, the operation will be explained according to the drawings. N chance, LE human analog signal is terminal 1 (1) l 1 (2)
, ...1 (N), and the A/D converter 2
(1), 2(2), . . . 2(N) are converted into digital codes. The conversion is performed, for example, at a sampling frequency of 48 KHz and at 16 binot quantization levels. The compression memory 3 compresses and multiplexes the sample data converted into digital codes on a 1/N time axis. The compression memory 3 sequentially performs compression in units of samples, so for example, N
Two systems of memory with a capacity of ×16 bits are sufficient. The compressed sample data is stored in the B huff memory 6 via the data bus 4. In the buffer memory 6, which is composed of two memories each having a capacity for one track, that is, N sectors, data is divided into sectors for each channel and sent to the data bus 4 again. The sample data separated and multiplexed for each channel is rearranged (scrambled) for each channel in an interleave memory 7.

For example, interleaving is applied between odd-numbered time-series data and even-numbered data to prevent consecutive time-series samples from being adjacent. This is because even if an error cannot be corrected during reproduction, correction by means of average value interpolation works effectively. The scrambled sample data is subjected to generation of an error correction code (ECC) from the sample data of each block in an ECC generation circuit 8 for each channel (in units of sectors) and compression of data in units of sectors. As error correction codes, parity codes that can be implemented with a simple configuration, adjacent codes that can correct double errors, Reed-Solomon codes, and the like are often used. Since it is not directly related to the present invention, no particular explanation will be provided. After generating the ECC, the ECC generation circuit 8 generates an error correction code (
ECC) and data samples are interleaved. The control code provided at the beginning of one sector is
1. Although not shown, data preset by an input means such as a keyboard and sequentially increasing sector address signals are generated by a control code generation circuit 9, and inputted to a CRCC generation circuit 10 together with a data string of a cheater block. CRCO code divides input data by a constant generating polynomial and sends out the remainder along with the data.If an error occurs in the transmission system on the way, a remainder will be generated if the detected data string is divided by the same polynomial used at the time of generation. It uses
It is known as an efficient error detection means with high detection ability. After generating CRCO in block units, NR
Modulation is performed from the Z data format to the signal format recorded on the recording medium. There are various modulation methods, but in order to achieve as high density recording as possible, a method with a large density index (tensity ratio) is desirable. A preamble, a postamble and a block synchronization signal (SYNC) are added by the ampoule/5YNG addition circuit 12, and the recording amplifier 1
3, the signal is converted into a signal for driving a semiconductor laser (not shown) which is the recording means of the optical head 14. The optical head 14 includes a semiconductor laser as a recording, reproducing and erasing light source, a converging optical system, reproducing and tracking.

It consists of a configuration including a focusing detection optical system, and a minute beam spot is irradiated onto an optical disk 15 that rotates at a constant rotation speed (for example, 3600 rpm), and recording and reproduction are performed by varying the irradiation power and beam shape.

Each erase function is realized.

The playback operation is performed as follows. The reproduction signal detected by the optical head 14 is amplified by the reproduction amplifier 17.

After undergoing processing such as equalization and waveform shaping, it is demodulated into the original NRZ data string by the demodulation circuit 18. The demodulated data string is SYN
A jitter absorption operation is performed in which the C signal is detected, written into the memory of the TBCl 9 block by block, and read out using a clock pulse frequency-divided from a crystal oscillator. The CRCC detection circuit 2o also detects errors on a block-by-block basis using the CRCC code, and sends an error flag signal to the error correction circuit 21 if there is an error. The error correction circuit 21 performs error correction on the data string containing errors on a sector-by-sector basis. After performing the reverse operation of interleaving performed up to the ECC generation circuit, use the error flag as a pointer to perform the ECC
Error data will be corrected. It also decompresses data that has been compressed in sectors. A deinterleaving memory 22 restores the scramble of the sample data, and an average value interpolation circuit 24 corrects any sample data that cannot be corrected. The output sample data of the average value interpolation circuit 24 is once sent to the data bus 4, and then sent to the buffer memory I.
Rell strikes in J 6'. The buffer memory 6' converts channel-specific data separated into sectors into data strings that are multiplexed in sample units. The output data passes through the data bus 4 again, and if fade-in/fade-out processing is required, is input to the multiplier 5, where the fade-in/fade-out processing is performed by digital calculation.
Receive out processing. Fade-in/out processing is not only used during playback, but also when performing insert or assemble editing operations, it performs cross-fade processing between already recorded data and newly added data to eliminate the sense of strangeness at connection points. need to be reduced. The output data of the multiplier 5 is again sent to the data bus 4 and input to the expansion memory 25. The expansion memory 25 performs the opposite operation to that of the compression memory 3, and separates and expands channel-multiplexed sample data for each channel. The data returned to the original sampling time series in the expansion memory 25 is sent to D/A converters 26(1), 26(2), . . .
・Returns to analog signal at 26(N) and connects to terminal 27(1)
.

27 (2), ..., output from 27 (N).

The reproduction operation of the control code is performed by the error correction circuit 21''
! , the data is reproduced through the same route as the data, and the control code is processed by the control code Tudor 23. The decoded data is sent to the CPU28
and are processed for simple display and control.

For example, when used for recording and reproduction as a 2-channel recorder, the formano ID is recorded as 2-channel mode. The compression memory 3 at the time of recording is an A/D converter 2
(1) l 2 The output data of (2) is alternately compressed. 1 ah and 2 channels are arranged alternately in the sectors, and channel numbers are assigned. In this case, the actuator 16 in the disk radial direction of the optical head 14 moves at a speed of 2/H compared to the case of N-channel recording/reproduction.
Controlled by the PU 28, two-channel recording and reproduction is performed.

Similarly to the compression memory 3 during recording, the expansion memory 25 during reproduction also performs distribution and expansion into two channels under the control of the CPU 28.

The above is the basic operation of one embodiment of the present invention.

In addition to the simple recording and reproducing operations described above, a multi-channel recorder requires various functions as described in the conventional example section.

First of all, in order for each channel to be able to record and play back arbitrarily, if you use the configuration shown in Figure 1 and the recording format shown in Figures 2 and 3, each channel is separated by ampoule bits, so the channels can be Additional recording, erasure, and playback can be performed at any time.

In order to fully realize the pan-nine-out function, which allows you to monitor the already recorded sound and record a new one on the second channel, or mix multiple channels and record a new one on other channels, the following steps are required. It is necessary to provide an additional optical head in addition to the optical head 14 shown in FIG.

FIG. 4 shows the configuration of a second embodiment of the present invention.

In the example shown in FIG. 4, the optical head 1 is placed on the diameter of the disk 15.
4. and 14' are arranged facing each other, and mode setting is performed by switching switches 29 and 30 so that one optical head performs reproduction and the other optical head performs recording. That is, one optical head performs a pre-reproduction function, and signals subjected to reproduction detection processing are stored in the buffer 7 memory on a track-by-track basis, and are recorded by the other optical head via a recording signal system. In this case, it is necessary to provide an offset so that the two optical heads 14, 14' do not scan on the same track but on tracks two tracks apart. In other words, the compression processing for each trunk in the recording circuit system causes a delay of more than one track, and also during playback.
Track extension processing and black) time axis correction for each lid,
Error correction processing causes a time delay equal to one track plus several sectors, so in order to re-record the playback signal, the playback optical head and recording optical head must be placed at least two tracks apart. It is necessary to provide a head.

Furthermore, since the two optical heads 14, 14' (ri 18d) face each other at an angle of 18d, there is a time difference corresponding to the trunk, but the amount subtracted from the delay amount in sector units described above is calculated by the buffer 7 memory 6. Can be adjusted by timing control.

By the above operations, while playing back the already recorded part, switching to the input signal at any part, re-recording the data of the sector where the editing connection was made on the optical disk, and recording the new input signal from then on. A pan nine-out operation is realized. The same applies to dubbing operations and insert processing by transferring between channels.

Furthermore, if both the optical heads 14 and 14' are enabled to read and erase data by using the switch 29 and the 3° switch as shown in FIG. 4, the acquisition time can be doubled compared to the single head configuration.

According to the embodiment of the present invention described above, recording and playback from 2 channels to n channels (n=2') can be performed by A/D, D/
It is possible to perform format configuration and error correction simply by switching the format conversion and its interface.

The main parts of recording and reproduction do not change in frequency and can be realized with the same configuration. Furthermore, the high-speed access allows editing operations to be performed with greater freedom and operability than with conventional tape recorders.

Effects of the Invention According to the present invention, multi-channel recording and reproduction having a power-law number of channels can be realized in the same format using one optical disc. The configuration and operation of the recording/reproducing device can be realized only by adding input/output A/D and D/A converters and interfaces and switching the speed of the actuator in the trunk width direction.

Furthermore, since the data of the same channel is arranged radially in concentric trunks, access on a channel-by-channel basis is easy.

Furthermore, in a device configured with a plurality of optical heads,
Editing functions such as inserting, assembling, and dubbing are realized through high-speed access, and the functions of conventional multichannel tape recorders and editing machines can also be realized.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a recording/reproducing apparatus in an embodiment of the present invention, FIG. 2 is a plan view schematically showing a recording trunk of an optical disk in an embodiment of the invention, and FIG.
FIG. 4 is a diagram showing a recording format of one sector in one embodiment of the present invention, and FIG. 4 is a schematic configuration diagram of a recording/reproducing apparatus in another embodiment of the present invention. 2(1)l..., 2(N)...A/D converter, 3...Compression memory, 8...ECC generation circuit, 14, 14' ...Optical head, 15
......Optical disk, 16.Actuator, 21..Error correction circuit, 23..Control code encoder, 25.--Extension memory, 26 ( 11,...l 2 e' (N)...
...D/person converter. Name of agent: Patent attorney Toshio Nakao and one other person” Figure 2

Claims (2)

[Claims] (1) means for A/D converting and compression multiplexing analog audio signals of up to N channels; means for dividing the compressed multiplexed data into N sectors for each channel;
means for configuring a recording format on a sector-by-sector basis;
A means for recording and reproducing N sectors per track on an optical disk having concentric recording tracks, a means for decoding the formant of data not detected for reproduction in sector units, and a means for decoding the formant of data not detected for reproduction in N channels. 1. A multi-channel recorder comprising means for decompressing data into N-channel data, and means for D/A converting into N-channel analog audio signals. (2) Optical heads that perform recording, playback, and erasing on the optical disk are arranged at positions offset by two trunks from each other on the diameter of the optical disk, so that recording, playback, and erasing can be performed using any of the optical heads. A multi-channel recorder according to claim 1, characterized in that: