JPS62192978A - Data transmission method - Google Patents

Abstract

PURPOSE:To raise the error correction capacity on data and additional information by performing the formation of a product code not only on the data but also on the additional information relating to the data when forming the product code high in the error correction capacity on the data. CONSTITUTION:Every plural data of predetermined number, the prescribed number of the additional information is added to form (n) rows X (m) columns of data blocks, the first error correction code is formed in the direction of the row of the data block and the second error correction code is formed in the direction of the column, respectively to form the product code and transmit the data. Thus, the error correction capacity is large on the data because of the product code, and the additional information is similarly processed to the data and the error correction code is formed, so that the error correction capacity on this additional information is large.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is used when transmitting data via a transmission (recording and re-transmission) medium with a slightly high error rate of 1, such as a magneto-optical disk. and preferred techniques.

[Summary of the invention]

In this invention, each predetermined number of data is divided into blocks, each block is configured to include additional information related to the data, a product code is formed for this block data, and this is transmitted. Not only can double errors be corrected in the row and column directions, but the same error can be corrected for additional information, which has the effect of making this additional information more resistant to errors and allowing for better data transmission. .

[Conventional technology]

A so-called hard disk device is conventionally known as a writable disk device for storing large-capacity information.

This is generally used for data storage in computers, and information is recorded in the form of intermittent (or spiral) tracks on a disk that rotates at a predetermined number of revolutions.

As shown in FIG. 4, writing and reading data to and from the hard disk drive (1) is done by the CPU (31) via the data bus (2). Since it is driven at a constant rotation speed that is unrelated to the rate (non-synchronized), a record of 22 is recorded at IJ (3). This is because the data handled is intermittent data.

Data is exchanged between the hard disk drive (1) and the CPU (31) using the RAM (4) as a buffer.
).

[Problem that the invention seeks to solve]

Since the above-mentioned hard disk recording W rule is generally performed under controlled conditions, the occurrence of berth 1 errors is small.

For this reason, the data format of this hard disk does not require a strong error correction code, and many formats do not have parity for error correction. Furthermore, even if there is, when one data block is arranged in a matrix, parity is usually assigned only to one direction of the row and column.

By the way, these days, it is called the new media era, and various kinds of information are provided to the world, and it has become so-called multimedia information.

This information includes intermittent data such as 'X1 computer data, semi-intermittent data such as still images and images, and completely continuous information such as digital audio.

It would be convenient if these various pieces of information could be stored on a disk and made available for use by the coaster as needed. However, as mentioned above, conventional disk drives generally record data at a constant rotational speed and are controlled and controlled by the CPU, and there has been no system that can handle multimedia information. .

Incidentally, magneto-optical disks are attracting attention as a rewritable mass storage device. Such mass storage devices have the potential to store multimedia information.

In the case of this magneto-optical disk, unlike a hard disk,
Burst errors are relatively common. Furthermore, because of the large capacity, various additional information is added to the data and recorded, but it is necessary to prevent this additional information from becoming unreadable due to errors. The present invention takes the above points into consideration and aims to provide a system with a strong error correction ability for both data and additional information.

[Means for solving problems]

Add a predetermined number of additional information to each predetermined number of pieces of data.
In addition, a data block of n rows x m columns is formed, and a first error correction code is generated in the row direction of this data block, and a second error correction code is generated in the column direction, respectively, to form a product code. to transmit data.

[Effect]

Since it is a product code, the error correction ability for data is large, and since the additional information is processed in exactly the same way as the data to generate the error correction code, the error correction ability for this additional information is also large.

〔Example〕

An example of the method of this invention will be explained with reference to the drawings, taking as an example the case where data is transmitted via a magneto-optical disk.

First, the format of a magneto-optical disk will be explained.

As shown in Fig. 2, on this magneto-optical disk (11), data is recorded as one track per rotation, forming a trunk (12) in an intermittent circular or spiral shape, and is reproduced from this trunk. be done.

One trunk (12) of this magneto-optical disk (11) consists of a plurality of sectors equally divided in the circumferential direction.
In each sector, a predetermined number of data with an error correction code, an error detection code, etc. generated and added is recorded.

In the case of FIG. 2, the l track is (n+
1) It consists of sectors; in this example, one track has 32 sectors.

The format of data recorded in one sector is, for example, as shown in FIG. That is, one sector has a header section, a data section, a gear/double section GAP provided after the ladder section, and after the data section, l! :
Consisting of

A preamble signal is recorded at the beginning of the header section.
The F code F, CG added and the address synchronization signal ASYNC added are recorded twice.

Further, in the data portion, a preamble signal is recorded at the U-port, and after that, data and an error correction code ECC and the like added to the data are recorded.

In this case, the standard amount of degree data recorded in the data section of one sector is 512 hides in consideration of use as a computer storage device.

In this case, the structure of the data section is as shown in FIG.

That is, in the case of FIG. 1, the number of data is 512 by 1- from Do to Ds, and the actual data is the track number TrNo and sector before the 512 by 1 data Do to D511 of the bag. Number Se.

12 bytes of additional information including data identification information
has been added. Then, 528 bytes with 4 bytes of error/detection CRC code generated for this total 524 bytes of data are 24X as shown in the figure.
It is arranged in a matrix as 22 bytes.

And 528 including 4 bytes of this CRC code.
The first error correction code Ci (for example, (28,
24) Reed-Solomon code) is added, and a 4-byte second error correction code (,2
(This is, for example, a (26, 22) Reed-Solomon code) is added.

In the figure, at the beginning of each row there is a synchronization signal (
In this example, a resync (referred to as resync) is added, and writing and reading are performed sequentially in the row direction.

From the above, in this case, the 512 bytes of data is
Additional information related to this data (including CRC code)
16 bytes are added to form a block of 528 bytes, which is arranged in 24 rows and 22 columns to generate and add parity ex in the row direction and parity C2 in the column direction to form a product code. 11) is recorded and reproduced as one sector.

In this case, what is recorded on the track is the data in the matrix shown in FIG. 1 read out sequentially in the row direction as serial data, and if a burst error occurs, the data in the row direction will be affected.

However, even if all of the data in the row direction is corrupted, for example, for one row, it can be corrected by the parity C2 in the column direction.

Therefore, even if the additional information section is completely destroyed due to a burst error, it can be restored correctly by error correction.

Note that in this example, the track number TrN.

and sector number Se are also recorded in a part of the header before the data section, and additional information that can be effectively used when playing data such as track number TrNo and sector number Se is doubled (part of the header is already Because it is overwritten, it is protected three times in this example.

In addition, instead of data in units of hides, it is also possible to divide 1 word of 16 bits or 12 bits of data into 512 bytes, form a product code, and transmit the data. At this time, for example, the identification information I of the additional information section
Information identifying the number of bits in one word is recorded in D.

Further, by changing the number of rotations of the disk, it becomes possible to record data with different transfer rates, and information indicating the transfer rate may be recorded in this identification information ID.

FIG. 3 is a block diagram of an example of a recording and reproducing system that records and reproduces information of various transfer rates in the sector format as described above by changing the number of rotations of the disk.

(Eng. 1) is a magneto-optical disk, and recording is performed on this disk (11) as a spiral track.
A recording/reproducing head (not shown) is subjected to tracking control so that it correctly scans the track that has been formed.

(21) is the J motor that drives the disk, and the disk (11)
is rotationally controlled by this motor so that it rotates at a predetermined speed with a constant angular velocity.

That is, this drive motor (21) is equipped with a frequency generator (
22) is installed BJ, and this frequency generator (22)
A frequency signal F proportional to the rotational speed of the motor (21)
G is obtained and supplied to the phase comparison circuit (23). - On the other hand, the speed reference signal REF is supplied to this phase comparator circuit (23). This speed reference signal RRT
? can be changed depending on the transfer rate of the data to be recorded or reproduced as described later, but the frequency generator when the disk (11) is rotating at the target rotation speed. This is a signal equal to the frequency of the output FG of (22). However, a signal with a frequency similar to that obtained by dividing the output FG may be used, and in that case, it is natural that the output FC is also divided by the same frequency division ratio and supplied to the comparator circuit (23).

The comparison output of this phase comparison circuit (23) is the integration circuit (24).
) to form a speed error voltage, which is supplied to the motor (21) via the motor drive circuit (25) so that the motor (21) rotates at an angular velocity according to the speed reference signal R3F. controlled by.

Next, to explain the recording system, (3), D is the input terminal for digital data, and as digital data, in addition to computer data, analog audio data is sampled at various predetermined sampling frequencies. Each sample value is sampled as a word 1: of a predetermined number of bits, and various other types of transferred digital data are input.

<31A) is an input terminal to which an analog 1 cog signal, such as an audio signal, is supplied.

When a digital signal is input to the digital signal input terminal (31D), a signal indicating the transfer rate may be sent along with this digital signal, but the signal indicating the transfer rate is sent to the input terminal (311?). Supplied.

Digital data from the input terminal (31D) is supplied to the selector (33). In addition, the input terminal (31A)
The analog signals are converted into digital signals in an A/D converter (32). This A/D converter (
The sampling frequency at 32) is, for example, 32kHz.
It is possible to switch to various frequencies such as , 44.1kHz, 48kHz, etc.;
.

It is possible to switch and output words of various bit numbers, such as 12 bits and 16 bits.

A digital signal from this A/D converter (32) is supplied to a selector (33).

The selector (33) selects either the digital signal from the input terminal (310) or the digital signal from the A/D converter (322) manually or by an external control signal.

The digital signal obtained from this selector (33) is EC
C encoder (34) and as described above 51
One sector of data is formed every two bytes. At this time, if ■ word 8-bit digital data is 512
One sector of data is formed for each word, but in the case of digital data where one word is not 8 bits, such as 12 bits, 16 bits, etc., one sector of data is formed by an integer word in Fig. 3.
There are cases where a row cannot be formed and a word spans two rows or even two sectors, but by setting the number of bytes in the row direction to an appropriate value in the sector format data structure shown in Figure 3, You can prevent it.

The data from the ECC encoder (34) is supplied to a recording process circuit (35), and after being subjected to appropriate modulation, it is supplied bit-serial to the head and recorded on the magneto-optical disk (11).

The rotational speed of the disk (11) at this time is synchronized with the transfer rate of digital data to be recorded as follows.

That is, during this recording, the switch (26) is connected to the terminal REC.
The signals from the speed reference generation circuit (36) are supplied as speed reference signals RIF and F to the phase comparator circuit (23).

When the digital signal to be recorded is a digital signal from the input terminal (310) and is so-called self-clocking data, the data from this input terminal (311) is sent to the speed reference generation circuit (36). I] sock is extracted from this data, the transfer rate is detected from this, and the detected transfer! A speed reference signal corresponding to the note is output from this.

When the digital signal from the input terminal (31D) is not a so-called self-clock signal, but a signal that indicates the transfer rate separately from the data, such as a clock signal,
This is supplied to the speed reference generation circuit (36) through the input terminal (31R), which detects the transfer rate from the signal and outputs a speed reference signal corresponding to the transfer rate.

In addition, when the signal to be recorded is a signal obtained by sampling the analog signal from the input device +7-(31^), switch (37) is turned on according to the selected sampling frequency and the number of bits for one sample as mentioned above. switching °ζ,
A speed reference signal corresponding to the transfer rate is obtained from the speed reference generation circuit (36).

If the transfer rate of the digital signal from the input terminal (311) is known, and it is not self-clock data and no signal is being sent, this switch (37 ) allows you to select a reference signal according to the transfer rate.

The motor (21) is driven so that the speed reference signal corresponding to the transfer rate thus obtained and the frequency signal FC from the frequency generator (22) match in phase (frequency match), and the disk (11) is driven at the transfer rate. Rotates at a rotation speed synchronized with.

In this case, the signal from the speed reference generation circuit (36) identifying the transfer rate 1- is sent to the ECC encoder (36).
4), and this transfer rate identification signal is recorded as part 2 of the data identification information ID in the additional information section of the data structure shown in FIG. The sampling frequency and the number of bits of the data word are also recorded as part of the fabric information HID.

Note that if the digital signal supplied to the input terminal (311) is ECC encoded with parity or other redundant bits added, these are once decoded to produce only the original digital data.

However, since the magneto-optical disk has a large capacity, it may continue to contain redundant bits. However, in that case, the transfer rate will be slightly different.

The identification signal indicating the transfer rate of recorded data is
It may also be recorded in the directory of the playback start area on the innermost or outermost circumference of the disc.

Further, the sampling frequency of the A/D converter and the number of bits of the data word may also be written in this directory and used during playback.

The relationship between practical applications, transfer rates, and disk rotational speeds is shown below.

Although the number of revolutions changes as shown below, the total number of bits for one disk does not change because the head is under tracking control so that it scans on the same track. In other words, the recording time differs depending on the transfer rate.

As is clear from this table, various standard rates for digital communication: 1.536 Mbps; 6. ], 44Mbp
s, 2.048 Mbps, etc.

It also becomes possible to record the sound of a digital audio tape recorder as is.

Next, the time of reproduction will be explained.

The digital signal reproduced by the head from the disk (11) is supplied to the reproduction process circuit (41) and demodulated.
Bit-synchronized playback is performed and converted into a digital signal. The output of this process circuit (41) is supplied to the decoder (46) of the CJ identification information ID, and the signal indicating the transfer rate recorded in the additional data section of each sector is decoded, and the decoded output is used as the speed standard. A speed reference signal corresponding to the decoded transfer rate is obtained from the generation circuit (47), which is then supplied to the phase comparator circuit (23) through the reproduction side terminal PB of the switch (26), and the disc is It rotates at a rotation speed synchronized with the transfer rate of recorded data.

The speed reference signal for controlling the rotation of the disk during playback can also be obtained by reading data indicating the transfer rate recorded in the directory of the disk prior to playback.

In addition, if the transfer rate of data recorded on the disk can be known from a memo or the like, manual switching is also possible.

In this way, the data reproduced at the rotation speed L7 in synchronization with the data transfer relay I is transferred to the F through the reproduction process circuit (41).
After being supplied to the CC decoder (42) and subjected to processing such as error correction for each middle sector, only the original data from which redundant focus has been removed is sent to the multiplexer (42).
43), when it is digital data, the output terminal (45
D), the analog signal is digitized, and if the analog signal is digitized, it is converted back to an analog signal by the D/A converter (44) and then output to the output terminal (45A).

The sampling signal frequency and the number of bits of the data word in this D/A: 1 heart rate (44) are also identified by the identification information ID.
It is possible to know this in advance by decoding it or by reading data recorded in the directory, and perform D/A conversion accordingly.

In this case, the identification information ID in the additional information section is part of the product code data and has high error correction ability, so it is easy to obtain the correct transfer rate, sampling frequency, and number of bits of the recorded data during playback. It is.

Note that although the above is a case where the rotation of the disk is controlled so that the rotational angular velocity is constant, it goes without saying that the present invention can also be applied to a case where the rotation of the disk is controlled so that the linear velocity is constant.

〔Effect of the invention〕

As described above, the present invention forms and transmits a product code with high error correction ability for data, but when forming this product code, not only the data but also additional information related to the data is also included. Since a product code is formed, this additional information is resistant to errors and can be effectively used on the data receiving (reproducing) side.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a product code used in the method of this invention,
FIG. 2 is a diagram showing a sector format of a magneto-optical disk to which the method of this invention is applied, FIG. 3 is a diagram showing an example of a disk recording/reproducing device to which this invention is applied, and FIG. 4 is a diagram showing data recording/reproducing by a hard disk device. FIG. 2 is a diagram illustrating the system. Do to Ds11 are data, and C1 and C2 are parities in the row and column directions.

Claims (1)

[Claims] A predetermined number of additional information is added to each predetermined number of pieces of data to form a data block of n rows by m columns, and a first error correction code is applied in the row direction of this data block and the first error correction code is applied in the column direction. A data transmission method in which second error correction codes are respectively generated to form a product code and data is transmitted.