JPH0636284B2 - Data recording / playback method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention converts an audio signal into a pulse coded modulation signal and records the pulse coded modulation signal on a disk at a constant linear velocity (hereinafter referred to as an optical digital audio disk. , DAD) or a digital audio tape (hereinafter D) for recording a pulse coded modulation signal on a magnetic tape.
The present invention relates to a data recording / reproducing method in the case of recording some data in place of an audio signal by using an AT) and using the DAD or DAT as a data file.

Configuration of Conventional Example and Problems Thereof In recent years, the capacity of data files has been increased, various recording media have been devised, and the recording media have been downsized.

Conventionally, there have been examples of using optical discs as data files, but all of them are discs that rotate at a constant angular velocity, and in this case, it was possible to put address information at a certain position on the disc. . However, when using a DAD that records and reproduces at a constant linear velocity,
If the data capacity contained in one address is fixed,
Since the signal is recorded in a spiral shape with a constant linear velocity, the address information cannot be recorded at a fixed position on the disc, and the address information is dispersed on the disc.
Since the DAD is for audio data, there is no example in which the DAD is used as a data file. Similarly, D
There is no example of using AT as a data file.

It is an object of the present invention to provide a data recording / reproducing method capable of recording arbitrary data in a DAD or DAT together with its address information and retrieving the data using the address information.

According to the data recording / reproducing method of the present invention, when recording on a data recording medium, in addition to the main channel, there is a sub-channel that is completely independent and time-divisionally recorded with respect to the main channel. Performs a rearrangement operation on the time axis and an operation of adding an error detection and correction code to a data string formed by adding at least address information indicating the position of the data in the recording medium for each predetermined length of data. The data string thus created is recorded, and an error detection code is added to at least the address information and recorded in the sub-channel.

Description of Embodiments An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a data structure diagram showing a temporal positional relationship between a main channel and a sub-channel at the time of recording / reproducing DAD data. In FIG. 1, S ₀ , S _1, ... Are sub-channel byte data recorded in time division with respect to the main channel, M ₀ , M ₁ , ... Are main channel byte data, and Q ₀ , Q. ₁ ..., P ₀ , P ₁
... is code data for error detection and correction for the main channel.

FIG. 2 is a block diagram showing the flow of a reproduction signal during DAD reproduction. In FIG. 2, 1 is the first
The data string shown in the figure, 2 is a sub-channel extracting circuit for separating the sub-channel from the data string 1, 3 is main channel data and code data for error detection and correction for main channel, 4 is sub channel data, 5 is for main channel An error detection / correction circuit, 6 is an error detection circuit for sub-channel address information, 7 is main channel data, and 8 is sub-channel time information.

Figure 3 shows the DAD for the address information to be put in the subchannel
FIG. 7 is a diagram showing a data format at the time of recording / reproducing data in one embodiment of the present invention when the time information of the sub-channel is used. In FIG. 3, T ₀ , T ₁ , ...
Is the time information obtained from the DAD sub-channel, A is the 8-byte sync pattern provided in the main channel data, B ₀ , B ₁ , ... Is 8-byte address information provided in the main channel, C ₀ , C ₁ , ... Are 2336 (98 × 3 ×) provided in the main channel.
This is a user area of 8-16) bytes.

In FIG. 1, each data is S ₀ , M ₀ , M ₁ , ..., M
₁₁ , Q ₀ , ... Q ₃ , M ₁₂ , ..., M ₂₃ , P ₀ ,
_{......, P 3, S 1,} M 24, is recorded on the disk in the order of _..., it is input as reproduction data in this order to the sub-channel extracting circuit 2. As shown in FIG. 1, the data is 1 byte for sub-channel data, 24 bytes for main channel data, and 8 bits for main channel error correction code.
One frame is made up of 33 bytes in total, and one block is made up of 98 bytes (98 frames) of subchannel data. First 2 of 98 bytes
Bytes are used as a block synchronization pattern, and one time bit is obtained for each byte in the remaining 96 bytes, for a total of 96 bits to obtain one time information. Also this 96
A 16-bit error detection code is included in the bits.

Now, only the sub-channel data is extracted from the data string 1 input to the sub-channel extracting circuit 2 and the sub-channel data 4 is input to the error detecting circuit 6. The error detection circuit 6 extracts the bits of the time information and then performs error detection using an erroneous detection code, and outputs the sub-channel time information 8 when there is no error. On the other hand, the main channel data and the main channel error detection / correction code data 3 which are the other output of the sub-channel extraction circuit 2 are input to the error detection / correction circuit 5 and, after undergoing an error detection / correction operation, the main channel data. Only the channel data 7 is output. In the error detection / correction circuit 5, various time axis operations are performed on the data, so that the main channel data 7 is the same as the data input order M ₀ , M ₁ , M _2, ... Output in a completely different order. This output data 7 is 8
The ones divided into bytes and rearranged are A in Fig. 3,
B _n, it is a _{C n (n = 0,1,2 ......)} . When the main channel data 7 is divided into 2352 (98 × 3 × 8) bytes, this length is the main channel data length corresponding to one subchannel block length, and the subchannel time information (address information) is used. Is the smallest unit that can be divided. Further, the time information T ₀ , shown in FIG.
The lengths of T ₁ and T ₂ are all equal and one block length, which is naturally equal to the time corresponding to 2352 bytes of main channel data. This 2352 bytes is one record,
An 8-byte synchronization pattern A is provided at the beginning of the record, and then 8-byte address information B _n (n = 0, 1,
2, ...) and the remaining 2336 bytes can be written in the user area C _n (n = 0, 1, 2)
......) As described above, the sub-channel and the main channel enter the dedicated error detection circuit or error detection / correction circuit, respectively, and only the main channel undergoes the time axis operation to be rearranged. As described above, Δtn (n = 0, 1,
2 ...) occurs on the time axis. This shift is constant on one disc, but it is necessary to have address information in the main channel in order to quantitatively grasp the shift. In addition, since the sub-channel address information has error detection capability but no error correction capability, when a data error occurs, the address information is lost. Therefore, for the above reason, the address information B _n (n = 0, 1 ...
...) is indispensable. To search for an arbitrary record C _n by using the address information of the main channel and the address information of the sub channel configured as described above, the following may be done. First, a rough search is performed using the information T _n contained in the sub-channel among the information T _n and B _n indicating the address of C _n . That is, Δ
Considering t _n , the DAD player is kept in the playback state from a position slightly before T _n , and after detecting the synchronization pattern A in the main channel, the subsequent address information B _m (m =
0, 1, 2) is equal to B _n , and the corresponding record C _n is obtained. Generally, the DAD player can specify the desired song and time by using the time information of the sub-channel. Therefore, by adding the main channel address determination circuit to the DAD player, the DAD can be easily converted into a data file. It is possible to use.

In the above example, one record is set to 2352 bytes, which is equal to the minimum addressable unit of the sub-channel. However, if the number of bytes smaller than this is set as one record and the synchronization pattern and the address information are added to each record, the main data is further detailed. You can split the channel. On the contrary, it is also possible to increase the number of data to be input in one record and configure a record having a larger number of bytes. Further, in the above example, the sync pattern is 8 bytes, but any length may be used as long as it can be recognized as a sync pattern, and the address information may have any length as long as the address information of the record can be identified. It is also possible to put data indicating the length of the record after the address information to make one record a variable length. Also D
Since AD uses an error detection / correction code for voice recording / reproduction, an error detection / correction code may be further used in the user area in order to obtain a high degree of data reliability.

An embodiment in which the present invention is applied to a DAD has been described above. However, in a DAT having a sub-channel that can be recorded in a time division manner with a main channel, a data string containing address information in addition to data in the main channel. It is clear that DAT can be used as a data file by recording at least the address information in the sub-channel.

EFFECTS OF THE INVENTION As is clear from the above description, according to the data recording / reproducing method of the present invention, when the data is recorded on the recording medium, the data is recorded not only on the main channel but also on the main channel in a time division manner. The main channel has a sub-channel, and at least the address information indicating the position of the data in the recording medium is added to the main channel for each predetermined length of data. The operation of adding the detection and correction code is performed, the data string created thereby is recorded, and the error detection code is added to at least the address information and recorded in the sub-channel. The excellent effect that it can be used as a file is obtained.

Furthermore, the address information of the main channel uses highly accurate address information that can indicate the exact position of the data in the recording medium, and the address information of the sub-channel shows the approximate position of the data in the recording medium. By using the address information with a low accuracy, it is possible to obtain the effect that the search operation can be performed quickly and any information can be obtained.

[Brief description of drawings]

FIG. 1 is a data structure diagram showing a temporal positional relationship between a main channel and a sub-channel during DAD data recording / reproduction, and FIG. 2 is a block diagram showing a state of a reproduction signal flow during DAD reproduction. FIG. 3 is a diagram showing a data format at the time of data recording / reproducing in one embodiment of the present invention when the time information of the DAD sub-channel is used as the address information to be put in the sub-channel. S _n (n = 0, 1 ...) ... Byte data of subcode channel, M _n (n = 0, 1, ...) ... Byte data of main channel, 7 ... Main channel data, 8
...... Sub-channel time information, T _n (n = 1, 2 ...
…） …… Time information obtained from the DAD sub-channel, B _n (0,1, ...) …… 8-byte address information provided in the main channel, C _n (n = 0,1,)
2 ……) …… Data area in the main channel.

Claims (2)

[Claims] 1. When recording data on a recording medium, in addition to the main channel, there is a sub-channel that is recorded completely independently of the main channel in a time-division manner. The data sequence created by performing the rearrangement operation on the time axis and the error detection and correction code addition operation on the data sequence formed by adding at least the address information indicating the position of the data in the recording medium. A data recording / reproducing method characterized by recording and recording at least the address information by adding an error detection code to the sub-channel. 2. The address information recorded in the sub-channel is detected to specify the approximate position of the desired data in the recording medium, and the address information recorded in the main channel is detected to record the desired data. Claim 1 characterized in that an accurate position in the medium is specified and reproduced.
The data recording / reproducing method described in the item.