JPS63281525A - Error detecting and correcting device - Google Patents

Abstract

PURPOSE:To increase an error detecting and correcting capacity by outputting blank information when a blank detecting device and the blank information are present and being equipped with a switching device and a decoder to output code information when they are absent. CONSTITUTION:At a blank detecting device 1, a detecting device 4 extracts a synchronizing signal from the code information of a block form, resets a block address detecting device 5 and a symbol counter 6 and obtains the synchronization of a block unit. The detecting device 5 resets a block address signal, the counter 6 generates a symbol address signal and both signals determine the symbol position in a track. Further, the identification signal of tracks A and B is added and a symbol position is determined. Since the address, in which the blank information exists, is determined by an action mode, the detecting device 7 detects the coincidence of the code and the address, in which both pieces of blank information exist, by an action mode signal. After the information, in which the blank information exists in the code information, is set wholly to the correct blank information value, decoding 3 is executed, therefore, the erroneous detection and the correcting capacity can be directed to the information excluding the blank information and the erroneous detection and correcting capacity of the information can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an error detection and correction apparatus for error detection and correction codes used when recording and reproducing analog information signals such as music signals using POM.

BACKGROUND OF THE INVENTION In recent years, with advances in digital signal processing technology and semiconductor technology, PGM signal recording and reproducing devices have made rapid progress.

In a 3M signal recording and reproducing device, blank data having a predetermined value is added to PCM information data as a method of keeping the data transfer rate constant during recording and reproducing and supporting multiple sampling frequencies. A method is used in which the number is set constant and then encoded using an error detection and correction code.

Hereinafter, with reference to the drawings, an example of such conventional technology will be described as "Digital Audio Tape Recorder System (R
-DAT) Recommended Design Standard J ('DIGITAL UDIOTAPlCRIC)
CORDKRSYSTICM(R-DAT)RICCO
The method described in the technical specification for a rotary head digital audio tape recorder (hereinafter referred to as R-DAT) entitled "MMRNDKD DESIGNSTANDARD" will be described.

The above-mentioned R-DAT has 48 Niden, 44
．． Three types of sampling frequencies are available: 1 K-an, 32 and 2 sampling frequencies.

In the R-DAT, the rotary head rotates once (mu).

B) The time required to scan two tracks is 3.
omsec, and it is possible to record and reproduce 46.592 bits of information data in this time.

Now, if the number of quantization bits is 16 bits, so one word is 16 bits, and the number of channels is 2, then 3om
1.456 words of information data can be processed per channel during sec.

When the sampling frequency is 48K)h, Fig. 3a
3 per channel during somsec as shown in
0X10 X48X10 = 1,440 words PC
It is necessary to process the information data converted into M, the remaining part 1
．． 456-1,440: Blank data in which all bit values are zero is added to 16 words.

Similarly, if the sampling frequency is 44.1 Kl-(z
The case of 32KHz is also shown in Figure 3, c.
By adding blank data as shown in the figure, the data transfer rate during recording and reproduction is kept constant.

FIG. 4 shows the configuration of the encoding device in the R-DAT. As shown in Figure 4, the information data converted into PCM is
The operation mode signal (
The R-DAT has six operating modes depending on not only the sampling frequency but also the number of quantization bits, the number of channels, and the track width.

A signal representing this operating mode is called an operating mode signal.

) is added to the necessary number of blank data to make the number of data to be processed constant, and then encoded by an error detection and correction code in the encoder 9, and outputs coded data to which parity data has been added.

A double-de-Solomon code is used as the error detection and correction code, and the processing unit of encoding is 8 symbols called symbols.
Data divided into pit units is used.

FIG. 6 shows the structure of the double Donromon code. As shown in Figure 6, there are 32 symbols vertically and 32 horizontally.
One unit is made up of symbols, and 32 symbols in the vertical direction represent the first codeword called the 01 sequence, and 32 symbols in the horizontal direction represent the 02 sequence.
It constitutes a second code word called a sequence.

The G1 series is a (32,28,5) Reed-Solomon code with 28 information data symbols and 4 parity symbols, and the C2 series is a (32,28,5) Reed-Solomon code with 26 information data symbols and 6 parity symbols. , 26, 7).

The minimum code amount distance for the G1 sequence is 6, and it is possible to correct up to 4 symbols when the error position is known, and up to 2 symbols when it is not. The minimum code amount distance for G2 series is 7, and when the error position is known, it is 6 symbols,
Otherwise, it is possible to correct up to 3 symbols.

If the structure of the double de Solomon code shown in FIG. 5 is taken as one unit, such a code is made into eight units during one rotation of the rotary head, that is, the number of bits of information data is 28X26X8X8 as described above. :46.592 bits can be processed.

When recording the above code data on a magnetic tape, the code data 32
128 blocks per track and 256 blocks per one rotation of the rotary head are recorded as block-format code data in which synchronization, ID code, block address, and parity symbols are added to the symbol.

FIG. 7 shows the configuration of a conventional error detection and correction device.

As shown in FIG. 7, in the conventional error detection and correction apparatus, reproduced coded data is input, decoded (error detected and corrected) in a decoder 1o, and information data is output.

Problems to be Solved by the Invention However, in the conventional error detection and correction device as described above, when detecting and correcting errors, the same processing is performed on information data and blank data, and blank data is processed in the same manner. The error detection and correction ability of the error detection and correction code was not fully utilized because it did not take advantage of the feature that it takes only the value of .

In view of the above problems, the present invention provides an error detection and correction device with improved error detection and correction capabilities.

Means for Solving the Problems In order to solve the above problems, the error detection and correction device of the present invention includes a blank detector that detects the presence of blank data in coded data, and a blank detector that is controlled by the blank detector,
a data switch that receives the code data and blank data as input, outputs the blank data when the presence of blank data is detected, and outputs the code data when the presence of blank data is not detected; The system is equipped with a decoder that performs decoding.

Effect of the Invention With the above-described configuration, the present invention decodes all data containing blank data in the encoded data after converting it into correct blank data, so that the error detection and correction ability of the error detection and delivery correct code is reduced except for blank data. The error detection and correction ability for information data can be improved.

Embodiment Hereinafter, an error detection and correction apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of an error detection and correction device according to an embodiment of the present invention. In Fig. 1, 1 is a blank detector;
2 is a data switch, and 3 is a decoder.

The operation of the error detection and correction device configured as described above will be explained below.

The reproduced code data is input to the blank detector 1,
The presence of blank data in the code data is detected and a blank data detection signal is output. Next, the code data and blank data are input, and the blank detector 1
The data switching device 2, which uses the blank detection signal from the control signal as a control signal, outputs blank data when the presence of blank data is detected, and outputs the code data when no blank data is detected. The decoder 3 decodes the output of the data switch 2 and outputs information data.

The operation of the blank detector 1 will be further explained below with reference to FIG. FIG. 2 is an internal configuration diagram of the blank detector 1. In FIG. 2, 4 is a synchronization signal detector, 6
is a block address detector, 6 is a symbol counter, and 7 is a block address detector.
is a blank address match detector.

A synchronization signal detector 4 extracts a synchronization signal from the block-format code data, and uses the synchronization signal to reset a block address detector 5 and a symbol counter 6 to achieve synchronization in units of blocks.

A block address detector 6 detects a block address and outputs a block address signal. Further, the symbol counter 6 counts symbol clock signals, which are clock signals for each symbol, and outputs a symbol ketores signal indicating a symbol address within a block. The position of a symbol within a track can be determined by the block address signal and symbol address signal, but since one rotation of the rotary head is a unit of processing,
The position of the symbol can be determined using three address signals including the track identification signals of both tracks B.

Since the address where blank data exists is determined by the operation mode, the blank address match detector uses the operation mode signal as a control signal to detect a match between the address of the code data symbol and the address where blank data exists. , outputs a blank detection signal.

As described above, in this embodiment, all data containing blank data in the reproduced encoded data is decoded after being set to the correct blank data value, so the error detection and correction ability of the error detection and correction code is blanked. The error detection and correction ability for information data can be improved.

Effects of the Invention As described above, the present invention includes a blank detector that detects the presence of blank data in code data, and is controlled by the blank detector, receives the code data and blank data as input, and detects the presence of blank data. Error detection is possible by providing a data switch that outputs the blank data when detected and outputs the coded data when it is not detected, and a decoder that decodes the output of the data switch. It is also possible to provide an error detection and correction device with improved correction capability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an error detection and correction device in an embodiment of the present invention, FIG. 2 is a block diagram showing the internal configuration of a blank detector in this embodiment, and FIG.
FIG. 4 is a data configuration diagram showing the structure of DAT information data and blank data; FIG. 4 is a block diagram of the R-DAT encoding device; FIG. 5 is a state diagram showing the structure of the R-DAT error detection and correction code; FIG. 6 is a block format of R-DAT code data, and FIG. 7 is a block diagram of a conventional error detection and correction device. 1...71 rank detector, 2...data switcher, 3...decoder, 4...synchronization signal detector, 6...・Block address detector, 6
...Symbol counter, 7...Blank address match detector. Name of agent: Patent attorney Toshio Nakao and 1 other person (Figure 2, Figure 3) (α) (b) (C)

Claims (1)

[Claims] a blank detector that adds blank data having a predetermined value to information data and detects the presence of blank data in the code data when decoding the code data encoded by the error detection and correction code; a data switch that is controlled by a blank detector, receives the code data and the blank data as input, outputs the blank data when the presence of the blank data is detected, and outputs the code data when the blank data is not detected; , and a decoder that decodes the output of the data switch.