JPH0724147B2 - Decoding method of multiple writing data - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention is for decoding data recorded by multiplexing and recording data such as an address and an error detection code or an error correction code on a recording medium such as an optical disk. The present invention relates to a method for decoding multiple write data.

B. Outline of the Invention According to the present invention, one unit of recording unit in which an error detection or correction code is added to data such as an address, like an identification section of each sector of an optical disk, is n-fold writing (n is an integer of 2 or more). ) And when playing back what was recorded on the recording medium,
A majority vote is taken only for each data portion of the reproduced signal of n units written n times, and a majority vote is taken only for each error detection or correction code portion. It is possible to perform highly reliable address reproduction by simple signal processing by performing error detection or correction processing on the combined one unit and reading the data.

C. Conventional Technology In recent years, recording media having an extremely high recording density such as optical recording media such as optical disks and optical cards have been put into practical use. Since the frequency of occurrence of burst errors and random errors is high, the same data should be used for particularly important data, such as the address data of each sector of the optical disk and the data such as the user registration number or password of the optical card. Multiple writing is done in duplicate.

That is, concentric or spiral (spiral) tracks are formed on a disc-shaped optical recording medium such as an optical disc or a magneto-optical disc, and one track is divided into a plurality of sectors. Further, in a card-shaped recording medium such as an optical card, for example, a band-shaped recording area is divided into a plurality of recording tracks. At a predetermined position of each recording block such as each sector or each recording track, for example, at each head position, a so-called formatting process prior to the start of use of a new disc or a so-called pre-formatting process on the side of the disc or card supplier is performed. As a result, a combination of an address and an error detection or error correction code (a unit which is a recording unit) is multiple-written, for example,
It is overwritten and recorded.

D. Problems to be Solved by the Invention By the way, a unit (data such as an address and a set of error detection or correction code) recorded in such a recording medium by generally n-fold writing (n is an integer of 2 or more) is recorded. ) Is reproduced and read, decoding (decoding) processing such as error detection and error correction is performed for each reproduction signal of each n-fold written unit, and error detection and correction processing for all units is performed. After that, the decision process of valid data must be performed by the majority decision logic, the decoding algorithm and hardware are complicated, and the time required for arithmetic processing and the like becomes long, which may hinder high-speed access. .

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a decoding method for multiple write data that can simplify decoding processing such as error detection and error correction without deterioration of reliability. .

E. Means for Solving the Problems In order to solve the above-mentioned problems, the method for decoding multiple-writing data according to the present invention is such that, in order to solve the above-mentioned problems, a unit consisting of data and error detection or correction code is n-fold written. (N is an integer of 2 or more) In a signal reproducing method for reproducing a recorded one, a majority decision of each data is made with respect to a reproduced signal for n units obtained by reproducing the n-overwritten unit. The selected data is combined with the code selected by adopting the majority decision of each error detection or correction code to form a new unit, and error detection or detection is performed for this combined unit. The feature is that the data is read after the correction processing.

F. Operation Since it is only necessary to perform error detection or correction processing on the new unit obtained by combining the above, it is not necessary to perform error detection or correction processing for each unit, so reliability is improved. The signal processing can be simplified without deterioration and the processing time can be shortened.

G. Embodiment Next, the basic principle of the reproducing operation of the signal reproducing method of the embodiment of the present invention will be described with reference to FIG.

Generally, one unit as a recording unit to be written n times (n is an integer of 2 or more) is, for example, important data such as address data and a code obtained by performing error detection coding or error correction coding on this data. In the example of FIG. 1, for example, n = 3 (triple writing), and the data and code of one unit are equal to 24 bits. That is, the first unit UT1 consists of 24-bit data D1 such as the above address and 24-bit error detection or correction code E1, UT2 also consists of D2 and E2, and UT3 consists of D3 and E3. There is. Play three such triple-written units UT1, UT2, UT3,
A majority of the data D1, D2, and D3 parts is taken and one data D _SL is selected. The majority decision at this time may be made according to the coincidence of the data values themselves, or may be made for each data bit of each data. In addition, a majority vote is similarly taken for each of the reference signs E1, E2, and E3 of each unit to select one reference code E _SL . The data D _SL and the code E _SL obtained in this way are combined to form one new unit, and a predetermined error detection or error correction decoding process (decoding process) is applied to this unit. I am trying to read the data.

By the way, as the multiple writing data, for example, address data of each sector of the optical disk can be cited. A specific example of the decoding method in the case of this address data will be described with reference to FIG.

That is, FIG. 2 is a diagram for explaining a specific example of a signal recording format on an optical disc as an example of an optical recording medium. In FIG. 2, one track on the optical disk is linearly stretched and the identification section (so-called ID section) of one sector is enlarged and schematically shown. 1
The track is composed of a plurality of sectors, and one sector is composed of, for example, a preformatted identification section IDR and a data section DTR as an area in which general sector data is recorded. At the head position of the identification section IDR, the recording section of the synchronization signal (PLO sync) PLOS for stabilizing the operation of the PLL circuit for clock generation when reading the data is arranged at the head, and the recording section of this synchronization signal PLOS Consecutively, the unit UT which is one recording unit of the sector identification address information is arranged in triple writing (n = 3). That is, three units UT1, UT2, and UT3 having the same content, which are recording units of sector identification address information, are sequentially arranged following the synchronization signal PLOS, and each recording unit or unit UT has a sync pattern address mark at the beginning. Address where SPA is arranged and consists of track address TA and sector address SA
AD is arranged, and then a CRC error detection code or an error correction code ECC composed of, for example, a BCH code is arranged. Here, as an example of the number of bits of each part, the track address
24 in total with 16 bits of TA and 8 bits of sector address SA
It is a bit address AD, and the length of the error detection or correction code ECC is 24 bits, which is equal to the address AD. It is assumed that an error correction code is used as this code ECC, and when the 24-bit address AD is encoded by the (48,24) extended BCH code, error correction up to 5 bits is possible.

When reading the identification section (ID section) of each sector in such a recording form and reproducing the address signal, conventionally,
After detecting or correcting each address AD of each unit UT1 to UT3 with error detection or correction code ECC,
The valid ones of these processed address values are compared with each other, and when these valid address values are different, the address value that is most matched by the majority logic (in the case of triple writing, of the three address values, (The two are the same). However, in such a method, decoding processing is required for all addresses of each unit in which multiple writing has been performed, and complicated decoding processing is continuously required for each unit in which multiple writing has been performed, resulting in a heavy hardware burden. .

Therefore, in the embodiment of the present invention, one address AD _SL is selected by taking a majority decision for each address AD1 to AD3 of the reproduction signal of each unit in which the multiple writing has been performed, and each code EC
After selecting one code ECC _SL by majority vote for C1 to ECC3, combine these AD _SL and code ECC _SL to form one new unit, and perform decoding processing only for this one unit. As a result, the number of decoding processes is reduced from the conventional three times (generally n times for n-fold writing) to one. That is, by adopting a majority decision before the decoding process, the process is simplified and the hardware load can be reduced. The error detection or correction capability in this case is almost the same as that in the case where the majority decision is taken after the decoding process for each unit in the related art, and there is no deterioration in reliability.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and for example, other than the optical disc, a recording medium such as a magneto-optical disc or an optical card can be easily applied. In addition to addresses, important data such as registration numbers, personal identification numbers, and directory information can be given as the multiple-written data.

H. Effect of the Invention According to the method for decoding multiple-writing data of the present invention, the number of times of decoding processing (decoding processing) for n-fold writing data can be significantly reduced without degrading the reliability, and the processing time can be shortened. In addition, the hardware load can be reduced and the configuration can be simplified.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of a data signal reproducing operation of an embodiment of the present invention, and FIG. 2 is a diagram showing an example of a signal recording format on an optical disk used in the present invention.

Claims (1)

[Claims] 1. A signal reproducing method for reproducing what is recorded by recording n units of data and error detection or correction code on a recording medium (n is an integer of 2 or more). In the reproduced signal for n units obtained by reproducing the unit, one data selected by taking a majority vote for each data portion and each error detection or correction code portion Multiplexing characterized by combining one selected code by adopting a majority vote to form a new unit and performing decoding processing for error detection or correction on this combined one unit. How to decrypt write data.