JPH06195947A - Disk recording medium - Google Patents

Abstract

PURPOSE:To provide a disk recording medium where digital data is recorded with the same signal form as conventional disks and information in the disk is accurately accessed. CONSTITUTION:A compact disk has the subcode changed with the period of 98 frames. The length of 0th to 97th frames is defined as one block. The same number of frames as the unit of the subcode are defined as one block of main digital data substituted for audio data. This main digital data has an address of each block. The subcode and main digital data are recorded in the same manner as audio data. When main digital data is accessed, both of the subcode and the address are used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc recording medium which uses a digital disc on which a 2-channel digital audio signal is recorded and which can store digital data other than the 2-channel digital audio signal.

[0002]

2. Description of the Related Art A system using an optical digital audio disc (referred to as a compact disc) is a disc system capable of reproducing high quality stereo music. If this disk system can reproduce digital data such as character data, display data, and program data in addition to stereo music without drastically changing the configuration of the player, a graphics device can be added by adding a display device. It is possible to realize a reproducing apparatus for visual information such as charts, statistics, and a picture book by still images, and a video game apparatus, and it is possible to expand the application range of the compact disc system. The current compact disk has a data storage capacity of about 500 Mbytes, which is an advantage over the storage capacity of a conventional flexible disk.

On the other hand, since the compact disc is designed to reproduce an audio signal, the beginning of the data on the disc is a relatively large unit such as a music unit or a phrase unit. However, as a storage device, 128
It is necessary to be able to read data in smaller units of about 10 Kbytes to bytes.

[0004]

DISCLOSURE OF THE INVENTION The present invention is capable of reproducing an existing disc reproducing apparatus for digital audio as it is or by changing a part of the disc reproducing apparatus. Instead of a digital audio signal, a program and a data are reproduced. It is an object of the present invention to provide a disk recording medium capable of storing digital signals such as.

[0005]

In order to achieve the above object, a disk recording medium according to the present invention has one frame of data composed of main digital data and sub-digital data for selectively reproducing the main digital data. The sub digital data is formed into a predetermined number of frames as one unit, and a plurality of frames, which is an integral multiple or an integer fraction of the number of frames in one unit of the sub digital data, constitutes one block of the main digital data. The main digital data of the block is characterized in that a digital signal formed by including the address of the main digital data is recorded.

[0006]

The relationship between the sub digital data and the main digital data is the same as that of the existing digital audio disc, and it is possible to maintain the same signal form or signal processing. Further, since an address is included in each block of the main digital data, desired data can be accurately read by both the sub digital data and this address.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is one in which the present invention is applied to a compact disc. The data structure when the signal recorded on the compact disc is audio data will be described with reference to FIGS.

FIG. 1 shows a data stream recorded on a compact disc. The 588 bits of the recording data are set as one frame, and the DC sync suppression bit RB of 3 bits is provided after the frame synchronization pulse FS of a specific bit pattern for each frame, and further, each of them is 14 bits of 0. Data bits DB of Nos. To 32 and DC suppression bits RB of 3 bits are provided alternately. The 0th one of the data bits DB is called a sub-coding signal or user's bit, and is used for reproduction control of the disc, display of related information and the like. 1-12, 17-2
The eighth data bit DB is assigned to the main channel audio data, and the remaining 13 to 16 and 29 to 32 are stored.
The second data bit DB is assigned to the parity data of the error correction code of the main channel. Each data bit DB is obtained by converting 8-bit data into 14-bit data by 8-14 conversion during recording.

FIG. 2 shows a state in which each data bit DB is 8 bits and 98 frames are sequentially arranged in parallel except the DC component suppression bit. The subcoding signals P to W of the 0 and 1 frames form a sync pattern which is a predetermined bit pattern. Regarding the Q channel, a CRC code for error detection is inserted in 16 frames on the terminating side of the 98 frames.

The P channel is a flag indicating a pause and music, and has a low level for music, a high level for pause, and a pulse of 2 Hz period in the lead-out section. Therefore, it is possible to select and play the designated music by detecting and counting the P channel. The Q channel can perform the same kind of control more complicatedly. For example, the information of the Q channel is taken into a microcomputer provided in the disc reproducing device, and immediately after the music is being reproduced, another music is reproduced. You can select a random song. Channels R to W other than this are used for displaying the lyricist, composer, commentary, poem, etc. of the song recorded on the disc, and for explaining by voice.

Of the 98 bits of the Q channel, the first 2 bits are the sync pattern, the next 4 bits are the control bits, the next 4 bits are the address bits, and the subsequent 72 bits are the data. Bits, and a CRC code for error detection is added at the end. The track number code TNR and the index code X are included in 72 bits of the data bits. The track number code TNR can change from 00 to 99, and the index code X can also change from 00 to 99. Further, the Q channel data includes a time display code indicating the time of the song and pause, and a time display code displaying the absolute time which continuously changes from the beginning of the program area of the compact disc to the end of the outermost peripheral side. Be done. These time display codes are
Each consists of a 2-digit minute, second, and frame code. One second is divided into 75 frames. In order to access a compact disc in units shorter than music, such as digital data, the above-mentioned time display code relating to absolute time is used.

As described above, in the compact disc, the minimum unit of change of the sub-coding signal is 98 frames. In this embodiment, when a digital signal other than a stereo music signal is recorded, the length of 98 frames from the 0th frame to the 97th frame is one block, as shown in FIG. As described above, 12 words of digital audio data are included in one frame, so that 24 bytes of digital data can be inserted in one frame. In FIG. 3, one sample of L channel of audio data and one sample of its R channel are 32 bits in total, and each frame has 6 rows.

A sync bit of 1 bit is added to the beginning of each row of 32 bits. The first 32 bits and the next 32 bits of the leading sync bit of the 0th frame are both 0. The first 32 bits of the leading sync bits of the even-numbered frames other than the 0th frame are set to 0, and the first 32 bits of the leading sync bits of the odd-numbered frame are set to 1. With this sync bit, it is possible to detect the position of the beginning of a block in units of 98 frames.

The above-mentioned one block is (24 bytes × 98)
= 2352 bytes). 2 Kbytes (2048 bytes) of data is inserted into one block, and the remaining 304 bytes (= 2432 bits).
As the sync bit, (6 × 98 = 588 bits) is used. Also, 7 is added to the first 32 bits of the 0th frame.
Since a bit mode signal and a 24-bit address signal are inserted, 1813 bits still remain in one block. The 1813 bits can be assigned to redundant bits when error correction coding is performed on one block of data.

The mode signal specifies the type of data of the block. For example, a mode signal is used to distinguish character data, still image data, and program code. The address signal is for specifying the data of the block. Furthermore, the reason why the sync bit of the even-numbered frame is set to 0 is that it is taken into consideration when forming a data block in units of two frames. In the case of a block having a size of 2 frames, a mode signal and an address signal are added to each block. As in one embodiment of the present invention, in the case of a block having a length of 98 frames, the codes for absolute time display of P data and Q data of subcoding signals in the same block are the same.

Recording of a digital signal in the format shown in FIG. 3 on a compact disc can be performed by the same method as that for an audio compact disc.
That is, a digital signal to be recorded is supplied to a digital input terminal of a digital audio processor, and this digital signal is converted into a video signal form and recorded by a rotary head type VTR. In this case, a T code for generating a sub-coding signal on the audio track at the beginning of the magnetic tape on which this digital signal is recorded.
Record OC (table of contents) data. Next, the TOC data reproduced from this magnetic tape is supplied to the sub-coding generation circuit, the reproduced digital signal is supplied to the encoder, the sub-coding signal is further supplied to this encoder, and the laser light is output from the encoder. Modulate. By this modulated laser light,
Make a master disk.

As another method of recording a digital signal, there is a method of accessing a hard disk memory, which can be accessed at high speed, with a minicomputer and supplying the digital signal to the encoder of the cutting system in real time.

FIG. 4 shows the structure of an example of a disc reproducing apparatus capable of reproducing the present invention. In FIG.
Reference numeral 1 denotes a compact disc to which the present invention is applied and in which the digital signal of the above-mentioned format is spirally recorded. The compact disc 1 is rotated by a spindle motor 2. In this case, the spindle motor 2 is controlled by the spindle servo circuit 3 so that the compact disc 1 rotates at a constant linear velocity.

Reference numeral 4 denotes an optical head. The optical head 4 includes a laser source for generating a laser beam for reading, an optical system such as a beam splitter and an objective lens, a light receiving element for the laser beam reflected by the compact disc 1, and the like. Have The optical head 4 can be moved in the radial direction of the compact disc 1 by a sled feed motor 5. The thread feed motor 5 is
It is driven by the sled drive circuit 6. Further, the optical head 4 is displaceable in two directions, that is, a direction orthogonal to the signal surface of the compact disc 1 and a direction parallel thereto, and is controlled so that focusing and tracking of laser light at the time of reproduction are always good. To be done. For this purpose, a focusing and tracking servo circuit 7 is provided.

The reproduction signal of the optical head 4 is supplied to the RF amplifier 8. The optical head 4 is provided with, for example, a focus error detection unit including a combination of a cylindrical lens and a 4-division detector, and a tracking error detection unit using three laser spots. This servo error signal is supplied to the focusing and tracking servo circuit 7.

The output signal of the RF amplifier 8 is supplied to the digital demodulation circuit 9 and the bit clock recovery circuit 10.
The digital signal recorded on the compact disc 1 is EFM-modulated. EFM modulation is a method of block-converting 8-bit data into a 14-bit preferable (that is, 14-bit pattern in which the minimum inversion time of the modulated signal is long and the low frequency components thereof are small). The digital demodulation circuit 9 is configured to perform EFM demodulation. The bit clock extracted by the bit clock reproduction circuit 10 is supplied to the digital demodulation circuit 9 and the spindle servo circuit 3.

The digital demodulation circuit 9 separates the sub-coding signals and supplies the sub-coding signals to the system controller 11. A CPU is provided in the system controller 11, and the system controller 11 controls the rotation operation of the compact disc 1, the thread feeding operation, the reading operation of the optical head 4, and the like. System controller 1
1, the control command is supplied via an interface 17 described later. That is, the system controller 11 controls to read out a desired digital signal from the compact disc 1 using the sub-coding signal.

The main digital data output from the digital demodulation circuit 9 passes through the RAM controller 12 and R
It is supplied to the AM 13 and the error correction circuit 14. This R
The AM controller 12, the RAM 13, and the error correction circuit 14 perform processing for removing time axis fluctuations, error correction, and error interpolation, and take out main digital data to the terminals 15L and 15R. When reproducing a compact disc on which audio data is recorded, a D / A converter is connected to each of the terminals 15L and 15R. Here, since the digital data is taken out as it is to the output, no D / A converter is provided, and the reproduced digital data is supplied to the data conversion circuit 16. The reproduced sub-coding signal is also supplied to the data conversion circuit 16, and the reproduced data is converted into a serial signal form.

This serial signal is the interface 17
The data for the system controller 11 is also supplied from the microcomputer system 18 via the interface 17. The microcomputer system 18 designates a read address and sends a control signal such as a start signal in addition to the read address to the interface 17 and the system controller 1.
Give to one. A list of a plurality of recording areas is recorded on the lead-in track of the innermost peripheral portion of the compact disc 1 by using the subcoding signal as an address, and this list is reproduced in the initial state when the reading of the compact disc 1 is started. Read by the microcomputer system 18.

FIG. 5 shows an example of the word format of the serial signal output from the data conversion circuit 16. This serial signal has 32 bits as one word,
The first 4 bits are the preamble, the next 4 bits are the auxiliary bits of the audio data, and the next 20 bits are the digital audio sample. When the digital audio sample has 16 bits, 16 bits are inserted from the least significant bit (LSB). Four bits are added after the digital audio sample. Of these 4 bits,
The bit labeled V is a flag that indicates whether the digital audio sample for that word is valid,
The bit indicated by U is each bit of the sub-coding signal, the bit indicated by C is a bit for identifying the channel, and P is a parity bit. Bit U of the sub-coding signal is inserted one by one in each of the word formats and transmitted sequentially.

To reproduce the disc 1 according to the present invention, first, the microcomputer system 18 executes a read command for a predetermined address.
This address is the code itself for displaying the absolute time of the Q channel, and via the interface 17,
It is supplied to the system controller 11. The system controller 11 controls the sled drive circuit 6 and moves the optical head 4 to a position near the target reading position while watching the sub-coding signal reproduced by the optical head 4.

In this example, the reproduced sub-coding signal contains an error, and in order to prevent a malfunction in which the set sub-coding signal is not reproduced and the access operation does not end, reproduction is started from a position several blocks away. I am trying. Then, when the reproduced sub-coding signal matches the specified address, or by starting the reproduction from the position of the correct sub-code signal in the vicinity and counting the frame synchronization signal, the number of target blocks is increased. After capturing the block front, the target block is captured by the address signal obtained by reproducing the main digital data.

With respect to the structure of the above-mentioned disc reproducing apparatus,
An operation keyboard may be added to the D / A converter and the system controller 11 so that a compact disc on which a stereo music signal is recorded can also be reproduced. Further, an access code signal encoded with an error correction code may be inserted into the other channels R to W in the sub-coding signal.

[0029]

According to the present invention, it is possible to provide a large-capacity disk recording medium as compared with a conventional flexible disk, and still read a digital signal in a unit suitable for handling. You can

Further, according to the present invention, with respect to a disc for reproducing a stereo music signal such as a compact disc which has already been commercialized, a signal form and a signal such as an error correction method and a recording data format. Digital data other than the stereo music signal can be recorded while maintaining the processing identity. Therefore, by adding a data processing unit such as a microcomputer, a color CRT, and a speaker to an existing disc player as an adapter, it is possible to reproduce various image information and audio information. Can be expanded.

Further, the disc recording medium of the present invention can accurately access desired digital data by utilizing both the address and the sub digital data added in the main digital data.

[Brief description of drawings]

FIG. 1 is a schematic diagram used for explaining a data structure of recorded data of a compact disc to which the present invention is applied.

FIG. 2 is a schematic diagram used for explaining a data structure of recorded data of a compact disc to which the present invention is applied.

FIG. 3 is a schematic diagram showing the configuration of one block when recording digital data in one embodiment of the present invention.

FIG. 4 is a block diagram showing a structure for reproducing the present invention.

FIG. 5 is a schematic diagram showing a word format of serial data in an embodiment of the present invention.

[Explanation of symbols]

 1 Compact Disc 2 Spindle Motor 4 Optical Head 5 Thread Feed Motor 11 System Controller 13 RAM 17 Interface 18 Microcomputer System

Claims (1)

[Claims] One frame of data is formed by the main digital data and the sub-digital data for selectively reproducing the main digital data. The sub-digital data has a predetermined number of the frames as one unit. A plurality of frames each having an integral multiple or an integer fraction of the number of unit frames are one block of the main digital data, and a main digital data of each block is recorded with a digital signal formed including an address of the main digital data. Disc recording medium.