JP3257811B2 - Syndrome generation circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a syndrome generation circuit for generating a syndrome for correcting an error in an information recording device, a communication path or the like.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing an example of a conventional syndrome generation circuit.

In FIG. 1, reference numeral 1 denotes a register for holding a syndrome, and 2 denotes a multiplier, which multiplies an output of the register 1 by a certain constant. Numeral 3 denotes a logical adder for adding the output of the multiplier 2 and the input data.

[0004]

Since the conventional syndrome generation circuit is constructed as described above, it is applicable to a data format in which the direction of the data input and the direction of the error correction codeword are different as shown in FIG. In order to generate a syndrome, it is necessary to once accumulate input data in a memory and input it to an error correction circuit in the order of codewords. The same applies to the case where a syndrome is generated for a product encoded data format, and C1 (a code word whose processing direction is different from the data input direction) and C2 (a code word whose processing direction is the same as the data input direction). Also, when the syndromes of (1) and (2) are simultaneously generated, there is a problem that the processing order of the codewords C1 and C2 is different and the circuit becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is not necessary to accumulate in a memory once to deinterleave input data with respect to a product encoded data format. It is an object of the present invention to provide a syndrome generation circuit that can easily generate a syndrome for a code word of.

[0006]

According to the present invention, there is provided a syndrome generation circuit which stores each data at a plurality of holding positions in the next holding position.
Input data to the first holding position
Holding, holding means for outputting the data of the last holding position, and multiplying means for multiplying a predetermined <br/> constant output data from the last holding position, output and 2D of the multiplication means
Read in order from the input word group corresponding to the array in a predetermined direction
Logically add the input word to be output and hold the addition result
And an adding means for inputting to the device, the said logical sum
Perform for all input words in the input word group, and
A syndrome is generated for the group in a direction orthogonal to the predetermined direction .

Also, a memory means having a plurality of addresses
And a sequential access address among the plurality of addresses.
Address control means for cyclically shifting
Multiply the data read from the address by a predetermined constant
A multiplying means corresponding to the output of the multiplying means and the two-dimensional array.
Input sequentially read from a group of input words along a predetermined direction
And the logical sum of the word and the result of addition
And an adding means for writing the logical addition into the input
Perform for all input words in the word group, and
On the other hand, a syndrome in a direction orthogonal to the predetermined direction is generated.
Is what it does .

[0008]

[0009]

[0010]

FIG. 1 is a block diagram showing an example of a syndrome generation circuit according to an embodiment of the present invention.

Referring to FIG. 1, reference numeral 11 denotes a register for cyclically holding a syndrome, 12 a multiplier for multiplying the register output by a constant, and 13 a logical adder for adding the output of the multiplier 12 to input data. is there.

In the syndrome generation circuit configured as described above, the input code words are sequentially shifted in the holding position.
Holding means (in this embodiment, register 1
1) and a predetermined fixed value for each held content of the holding position.
Multiplication means (multiplier 12) for multiplying a number;
Performs a logical addition operation on the output and the subsequent input codeword,
Holding the calculation result while sequentially shifting the holding position cyclically
Logical addition means (logical adder 13) held by the means
The input code word
Is generated, it is possible to obtain a syndrome having a different data input direction.

The operation of FIG. 1 will be described below with reference to FIG.

The input order of the data format shown in FIG. 4 is, as shown in the figure, input R11, R21,.
R12, R22, ..., Rm2, R1n, R2n, ..., R
mn. The order of the codewords in this case is [Rm
1, Rm2,..., Rmn]. So register 1
.., Rm1 are cyclically shifted with respect to inputs R11, R21,..., Rm1, and R11, R21,. Next input R
12, R22,..., Rm2
When the 1 is cyclically shifted again, the result of multiplying each value of the previous held data by the value α ⁱ of the multiplier 12 and the exclusive OR of the input data, R11 · α ⁱ + R12, R21 · α
ⁱ + R22,..., Rm1 · α ⁱ + Rm2 are logical adders 1
3 and are again input to the register 11 and held. By repeating this, when all the data in the data format has been input, a syndrome for α ⁱ for each codeword is generated in each register 11.

Therefore, by using the syndrome generation circuit shown in FIG. 1 in correspondence with the value α ⁱ of the multiplier 12 by the number of syndromes, all the syndromes for the code word C1 having different processing directions can be obtained by one data input. be able to. Further, the code word C2 having the same data input direction and processing direction can be obtained by the syndrome generation circuit shown in FIG. 3, so that the data input direction and the processing direction can be changed by combining the syndrome generation circuits. With the same codeword C2 and data input, syndromes of a codeword C1 having different processing directions can be obtained at a time.

In the above-described embodiment, it goes without saying that the register section of the syndrome generation circuit can be similarly achieved even if the configuration is such that the address control of the memory, not the register, is performed cyclically (see FIG. 2).

FIG. 2 is a block diagram showing an example of a syndrome generation circuit according to another embodiment of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals.

In the figure, reference numeral 5 denotes an address control means constituted by a counter for cyclically outputting values from 0 to m-1, for example, for controlling access to the storage medium 4.

In the syndrome generation circuit having the above-described configuration, the holding means is provided with an address having a different holding position.
Constituted by a storage medium 4, which is specified by the scan, then hold the input data in the storage medium 4 while the address control unit 5 is visited access address, successively multiplies the data and constants multiplier 12 is read from each address Do, logical adder 1
3 executes a logical addition operation between the output of the multiplier 12 and the input data, and the address control means 5 accesses the operation result.
The address is stored in the recording medium 4 while circulating ,
Perform logical addition operation a predetermined number of times, and
It is possible to obtain a syndrome of a code word having a different word direction .

[0020]

As described above, according to the present invention,
The memory generation circuit stores each data at multiple
Input data to the first holding position
Holding, holding means for outputting the data of the last holding position, and multiplying means for multiplying a predetermined constant on the data output from the last holding position, output and 2D of the multiplication means
Read in order from the input word group corresponding to the array in a predetermined direction
Logically add the input word to be output and hold the addition result
And an adding means for inputting to the device, the said logical sum
Perform for all input words in the input word group, and
Since the syndrome is generated for the group in the direction orthogonal to the predetermined direction, it is not necessary to provide a memory for storing the entire input data in order to deinterleave the input data, and the circuit configuration can be simplified. Further, a syndrome of a code word in a direction different from the data input direction can be obtained with a simple circuit configuration.

A syndrome generation circuit according to another aspect.
Comprises a memory means having a plurality of addresses;
The address is sequentially shifted cyclically in the address.
Address control means to read from the access address.
Multiplication means for multiplying the found data by a predetermined constant;
From the output of the multiplication means and the input words corresponding to the two-dimensional array
Logical addition of input words read in order along the specified direction
And writing the addition result to the access address.
Means for performing the logical addition on all the input words in the input word group.
For the input word group, and
Generates a syndrome in the direction orthogonal to the direction.
The entire input data to deinterleave the force data
There is no need to provide a memory for storage, and the circuit configuration can be simplified.
Simply can. In addition, marks in a direction different from the data input direction
The syndrome of the issue language can be found in the barber easily by the address control.

Therefore, there are the effects that the scale of the conventional syndrome generation circuit can be significantly reduced and the syndrome generation control can be simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a syndrome generation circuit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a syndrome generation circuit showing another embodiment of the present invention.

FIG. 3 is a block diagram illustrating an example of a conventional syndrome generation circuit.

FIG. 4 is a diagram showing a data format of input data.

[Explanation of symbols]

 11 Register 12 Multiplier 13 Logical adder

Claims (2)

(57) [Claims] 1. A method according to claim 1 , wherein each data at a plurality of holding positions is stored in a next holding position
Input data in the first holding position
Holding means for holding and outputting data of the last holding position ;
Multiplying means for multiplying the data output from the last holding position by a predetermined constant, and an output of the multiplying means and a two-dimensional array
From the input word group corresponding to
Means for logically adding the input word to
And an adding means for inputting the logical addition to the input.
Perform for all input words in the word group, and
A syndrome generation circuit that generates a syndrome in a direction orthogonal to the predetermined direction . 2. A memory means having a plurality of addresses;
The access addresses are sequentially cycled through the plurality of addresses.
Address control means for shifting the access address
Multiplying the data read from the address by a predetermined constant
Means, an output of the multiplication means and an input corresponding to the two-dimensional array.
Input words that are sequentially read from the group of power words along a predetermined direction;
Is logically added, and the addition result is written to the access address.
Input means for performing the logical addition on the input word group.
For all input words of
To generate a syndrome in a direction orthogonal to the predetermined direction.
Syndrome generating circuit, characterized in that that.