JPH0576716B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention converts an audio signal into a pulse code modulation signal (hereinafter abbreviated as PCM signal).
Data when using a PCM audio disk playback device that arranges PCM signals in a spiral pattern on the disk, records some data instead of the audio signal, and uses the PCM disk as a data file. This relates to the recording method.

Conventional configurations and their problems Conventionally, there have been examples of using optical disks as data files, but all of them are disks that rotate at a constant angular velocity, and in this case, address information is stored at a certain position on the disk. It was possible to include However, when using an optical disk with a constant linear velocity, the rotation speed at the inner circumference is fast,
Since the rotation speed at the outer periphery is slow, if the amount of data contained in one address is constant, the address information cannot be recorded at a fixed position on the disk and is dispersed.

Conventionally, there has been no example in which address information has been recorded on such a disk with a constant linear velocity.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a data recording method that allows arbitrary data to be retrieved from information recorded on a PCM disk with a constant linear velocity based on address information.

Structure of the Invention The data recording method of the present invention uses a read-only optical disk that rotates at a constant linear velocity as a recording medium for digital signals, and uses one specific bit among the 16 bits that make up one word as an address recognition bit. ,
Address recognition bits are set for one or more consecutive words for each fixed amount of continuous data, and error detection is performed for the bit address pattern other than the address recognition bit of the word in which the address recognition bit has occurred, the address recognition bit, and the address pattern. The code is arranged, the address recognition bit is detected during playback, the address information is read, and an error is detected. If there is no error, the subsequent data can be read out. It is possible to search for data at any address.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram schematically showing the format of the address area portion of continuous data recorded on a disk.

Optical PCM disks use 16 bits as one word, which is the smallest unit of information. In FIG. 1, there is a 4-word address area for each fixed amount of continuous data, which separates data areas. In order to distinguish between the address area and the data area, the first bit of 1 word = 16 bits is set as address recognition bit 1. For example, if the address recognition bit of the address area is set to "1" and the address recognition bit of the data area is set to "0", the address area can be recognized by monitoring the address recognition bit during address search.

Since 1 bit is used as an address recognition bit, 1 word has 15 bits remaining, so when recording, 16 bits remain.
Bit data must be converted into 15-bit data in advance. Figure 2 shows how 16-bit data is distributed into 15-bit units. 1st
The word contains one address recognition bit 1 and the first 15 bits of data A2. The second word contains 1 address recognition bit 1, the last 1 bit of data A2, and the first bit of data B3.
Contains 14 bits. The third word contains one address recording bit 1, the last two bits of data B3, and the first 13 bits of data C4. Similarly, the 16 bits in the data are shifted by 1 bit across two words, and in the 16th word, address recognition bit 1 is shifted by 1 bit, and data N is shifted by 1 bit.
The last 15 bits of 5 are entered. In other words, the data capacity that can be recorded is 15 words in an area of 16 words.

In Figure 1, the address area is an area for 4 words, but 1 bit is used for each word as an address recognition bit, so
There are 4 bits in total, and the number of bits that can be used as address information is 60 bits. 19 as address value
An 11-bit cyclic code (hereinafter abbreviated as CRC) is added to protect the address.
These steps were repeated twice and recorded for a total of 60 bits. By adding CRC, it is possible to prevent incorrect address recognition due to code errors.

As mentioned above, the address recognition bit and address
By arranging the CRC for data recognition, it becomes possible to search for necessary data when playing a disc.

To help understand this embodiment, a method for reproducing a disc recorded in the above format will be described. The PCM disk format includes an auxiliary data section called a subcode, which includes a code called a Q code. Usually, the Q code records the song number of each song, the time in each song, the time throughout all songs, etc. The search function of the PCM audio disc playback device uses the above-mentioned time information. Its time resolution is 1/75 second.

In this embodiment, in order to have format compatibility with a music PCM disk playback device,
The search function uses time information. In other words, it is a two-stage system in which address information and time information are in a one-to-one correspondence, the requested address is converted to time, a search is performed to the vicinity, and the correct address is read while reproducing from that point. It's becoming a method.

The amount of data contained in one address is in units of 1/75 seconds, which is the same as the minimum unit of time information.
It becomes 2352 bytes. After subtracting the address recognition bit and address part, it becomes 2200 bytes or 1100 words. This unit will be called one block.
Also, 8 blocks will be called one record.
These relationships can be summarized as follows.

1 block = 2200 bytes = 1100 words 1 record = 8 blocks 1 disk (average) = 33751 records Therefore, to represent an address, the number of records is 16 bits, the number of blocks is 3 bits,
A total of 19 bits are required.

Next, an apparatus for realizing the above embodiment will be explained. FIG. 3 is a block diagram of an apparatus including a preprocessing section of a recording machine for recording data using the method of this embodiment. Since current PCM audio disks are for playback only, this equipment belongs to the equipment of the disk manufacturer. Assuming that there is some kind of database 10, the data converter 11 converts 16 words of data into 15 words of data using the method described in FIG. On the other hand, the address generation section 12 generates address recognition bits and address values using the synchronization signal from the editing machine 14, and switches between the output of the data converter 11 and the output of the address generation section 12 using a switching circuit 13 to generate the original music signal. is input to the encoder 15 for cutting onto a disc. The address value and the time information generated by the encoder 15 are synchronized by the editing machine 14.

FIG. 4 shows a block diagram of a reproducing machine in which a PCM audio disk recorded and cut by the apparatus of FIG. 3 is used as a data file.

Here, assuming that the address of the data to be retrieved is known, when the address value is input to the control section 24, the control section 24 converts this into time information of the PCM disk and transmits it to the player 20. The player 20 searches according to the time information and starts playing from that part. The address detection unit 21 monitors the digital output data of the player 20,
The address part is detected by the address recognition bit. The data is further sent to the address recognition section 22, which recognizes the address value of the address area detected by the address detection section 21, and further performs a CRC check. If the CRC is correct, the recognized address value and the address value input to the control section 24 are compared, and if they are equal, the data is transferred to the data conversion section 23. The data conversion section 23 converts the received data of 15 bits per word into data of 16 bits per word by inverse conversion of the method described in FIG. The data output by this is the data included in the desired address.

Effects of the Invention As is clear from the above explanation, the present invention has the following effects:
Address information to the PCM audio disk,
Of the 16 bits that make up one word, one specific bit is used as an address recognition bit, and for each fixed amount of continuous data, the address recognition bit is set for one or more consecutive words, and the word with the address recognition bit is set. The data is recorded in a format in which an address pattern and an error detection code for the address recognition bit and address pattern are placed in bits other than the address recognition bit of the address recognition bit, and the address recognition bit is detected during playback, then the address information is read, and error detection is performed. If there is no error, the data to be read after that can be read out. Therefore, the address can be detected by reading only the word for which the address detection bit is set, making it extremely easy for the playback device to read out the data. Easy to configure. Further, by simply adding some additional circuitry to the audio disc playback device, it is possible to easily search for necessary data as a data file.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the format of the address area within continuous data recorded on a disk, Figure 2 is a diagram showing how data is distributed in the data area, and Figure 3 is a diagram of the recording machine of the embodiment. block diagram,
FIG. 4 is a block diagram of the regenerator of the embodiment. 1...Address recognition bit, 2...Data A,
3... Data B, 4... Data C, 5... Data N, 10... Database, 11, 23... Data converter, 12... Address generation unit, 13... Switching circuit, 14... Editing machine , 15...encoder,
20... Player, 21... Address detection section, 2
2...Address recognition unit, 24...Control unit.

Claims (1)

[Claims] 1. An optical disk for reproduction only that rotates at a constant speed is used as a recording medium for digital signals. Among the 16 bits that make up one word, one specific bit is used as an address recognition bit. Address recognition bits are set consecutively for at least one word, and an address pattern and an error detection code for the address recognition bits and address pattern are placed in the bits other than the address recognition bits of the word in which the address recognition bits were set, and the address recognition bits are set during playback. Detects the recognition bit, then reads the address information,
The data recording method is characterized in that it further performs error detection, and if there is no error, the subsequent data can be read out, thereby making it possible to search for data at any address on the disk.