JPH0783277B2 - Original representation format conversion circuit on Galois field - Google Patents
Original representation format conversion circuit on Galois fieldInfo
- Publication number
- JPH0783277B2 JPH0783277B2 JP61232003A JP23200386A JPH0783277B2 JP H0783277 B2 JPH0783277 B2 JP H0783277B2 JP 61232003 A JP61232003 A JP 61232003A JP 23200386 A JP23200386 A JP 23200386A JP H0783277 B2 JPH0783277 B2 JP H0783277B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- galois field
- output
- multiplication
- conversion circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Detection And Correction Of Errors (AREA)
- Error Detection And Correction (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明はデジタル処理回路に関し、特にその符号化・復
号回路において用いられるガロア体(galois体:加減乗
除の四則演算が行える元の集合で元の数が有限であるも
の。通常、qを元の数としてGF(q)で表わす。)上の
元の指数・ベクトル変換回路に関する。Description: TECHNICAL FIELD The present invention relates to a digital processing circuit, and particularly to a Galois field used in an encoding / decoding circuit, which is an original set capable of performing four arithmetic operations of addition, subtraction, multiplication and division. A finite number, usually represented by GF (q) where q is the original number).
従来、ガロア体上の元の指数・ベクトル変換は処理が非
常に複雑であるので、指数・ベクトル変換回路としては
ROM(リードオンメモリー)に指数−ベクトル対応テー
ブルを生成しておきそれにより変換処理を行なうのが通
常であった。Conventionally, the processing of the original exponent-vector conversion on the Galois field is very complicated, so as an exponent-vector conversion circuit,
It is usual to generate an index-vector correspondence table in ROM (read-on memory) and then perform the conversion process.
しかしながらROMは回路構成が大きいので回路構成の簡
略化には不適であった。このためROMに変わる簡単で回
路量の小さい指数・ベクトル変換回路が望まれていた。However, since the ROM has a large circuit configuration, it is not suitable for simplifying the circuit configuration. Therefore, an exponent-vector conversion circuit that can be easily replaced with a ROM and has a small circuit amount has been desired.
本発明は、ROMを用いず、ゲート回路及び乗算回路によ
ってガロア体上の元の指数・ベクトル変換を行なう簡単
な回路の指数・ベクトル変換回路を提供することを目的
とする。It is an object of the present invention to provide an exponent / vector conversion circuit which is a simple circuit for performing original exponent / vector conversion on a Galois field by a gate circuit and a multiplication circuit without using a ROM.
かかる目的を達成するために、本発明では、αを原始元
とするガロア体GF(2m)上の任意の元αnについて、指
数表現をn=2m-1・Nm-1+2m-2・Nm-2+・・・+2・N1
+N0とするとき、入力されるNi(i=0,1,・・・,m−
1)が1のときにαの2i乗を出力し、0のときに1を出
力する論理回路手段と、記憶手段と、該記憶手段の記憶
内容と前記論理回路手段からの出力とを乗算する乗算手
段と、該乗算手段の乗算結果を前記記憶手段に更新記憶
するように制御する制御手段とを具える。In order to achieve such an object, according to the present invention, an arbitrary element α n on a Galois field GF (2 m ) having α as a primitive element has an exponential expression of n = 2 m-1 · N m-1 +2 m. -2・ N m-2 + ・ ・ ・ +2 ・ N 1
+ N 0 , the input N i (i = 0,1, ..., m−
When 1) is 1, α 2 i is output, and when it is 0, 1 is output. Logic circuit means, storage means, the storage content of the storage means and the output from the logic circuit means are multiplied. And a control means for controlling so as to update and store the multiplication result of the multiplication means in the storage means.
以下、本発明の実施例について説明する。 Examples of the present invention will be described below.
指数・ベクトル変換回路においては指数nはバイナリで
入力され、次のように表される。それからαnを生成す
るために次のように分解される。In the exponent / vector conversion circuit, the exponent n is input in binary and expressed as follows. It is then decomposed to produce α n as follows.
n=N7・128+N6・64+N5・32 +N4・16+N3・8+N2・4+N1・2+N0・1 αn=αN7・128・αN6・64・αN5・32・αN4・16 ・αN3・8・αN2・4・αN1・2・αN0 従って、Ni(i=0・・・7)が1のときα2^iを出力
し、0のとき1を出力する回路を構成し、その出力を順
次乗じていけばよい。そのブロック図を第1図に示し、
その動作タイミングを第2図に示す。符号長nのバイナ
リー表現がN0→N7の順で送られてきたときバスラインY
にはαN0→αN7・128が出力され乗算回路2に送られ
る。乗算回路2の出力Zからは順次αN0〜αN7・128を
乗じた出力が出力される。その出力をレジスタ3にとり
こみ、乗算回路2のもう一つの入力端子Xに出力する。
ただし、Xには、最初YがαN0を出力した時1を出力す
るようにレジスタの内容をセツトしておく。αN7・128
が出力されたときαnが生成される。n = N7 ・ 128 + N6 ・ 64 + N5 ・ 32 + N4 ・ 16 + N3 ・ 8 + N2 ・ 4 + N1 ・ 2 + N0 ・ 1 α n = α N7 ・ 128・ α N6 ・ 64・ α N5 ・ 32・ α N4 ・ 16・ α N3 ・ 8・ α N2・ 4・ α N1 ・ 2・ α N0 Therefore, a circuit that outputs α 2 ^ i when Ni (i = 0 ... 7) is 1 and outputs 1 when Ni is 0, and outputs it sequentially Just multiply it. The block diagram is shown in FIG.
The operation timing is shown in FIG. When the binary representation of code length n is sent in the order of N0 → N7 Bus line Y
Α N0 → α N7 · 128 is output to and is sent to the multiplication circuit 2. From the output Z of the multiplication circuit 2, an output obtained by sequentially multiplying by α N0 to α N7 · 128 is output. The output is taken into the register 3 and output to the other input terminal X of the multiplication circuit 2.
However, the contents of the register are set in X so that 1 is output when Y Y first outputs α N0 . α N7 ・ 128
Is output, α n is generated.
HCKは、N0〜N7が出力されている間図示しないクロツク
発振器から出力されているクロツクパルスである。HCK is a clock pulse output from a clock oscillator (not shown) while N0 to N7 are output.
ここでN0〜N7に従ってαN0〜N7・128を出力する指数/
ベクトル回路1の構成を第3図に示す。Here, the index that outputs α N0 to N7 · 128 according to N0 to N7 /
The configuration of the vector circuit 1 is shown in FIG.
この回路は従来はROMによって生成されていたが本実施
例ではゲート回路によって構成してある。尚、第3図に
おいて▲[+]▼はExclusive OR(排他的論理和)回
路、 はバスラインを示す。第3図の回路は既約多項式がp
(x)=x8+x4+x3+x2+1の場合においてNi=1(i
=0→7)のとき順次α=(01000000),α2=(0010
0000),α4=(00001000),α8=(10111000),α
16=(00110010),α32=(10111001),α64=(1111
1010),α128=(10100001)を出力し、Ni=0のとき
1を出力するゲート回路構成になっている。This circuit was conventionally generated by a ROM, but in this embodiment it is constituted by a gate circuit. In FIG. 3, ▲ [+] ▼ is an Exclusive OR circuit, Indicates a bus line. In the circuit of FIG. 3, the irreducible polynomial is p
(X) = x 8 + x 4 + x 3 + in the case of x 2 +1 Ni = 1 (i
When = 0 → 7) α = (01000000), α 2 = (0010
0000), α 4 = (00001000), α 8 = (10111000), α
16 = (00110010), α 32 = (10111001), α 64 = (1111
1010), α 128 = (10100001), and outputs 1 when Ni = 0.
以上の構成によって、指数表現nから、ベクトル表現α
nへの変換を簡略化されたゲート回路と乗算回路によっ
て行なうことができる。With the above configuration, from the exponent expression n to the vector expression α
The conversion to n can be performed by a simplified gate circuit and multiplication circuit.
第1図の例ではαn生成までにN0〜N7をシリアルに出力
するために8クロツク入力必要であるが、クロツク入力
数を少なくしたい場合N0〜N7をパラレルに出力し、乗算
回路をそれに応じて複数もつことによってクロツク入力
にすることもできる。その場合回路量が多少本実施例よ
り多くなる。In the example of FIG. 1, 8 clock inputs are required to serially output N0 to N7 until α n is generated. However, if you want to reduce the number of clock inputs, N0 to N7 are output in parallel and the multiplication circuit responds accordingly. It is also possible to make a clock input by having multiple clocks. In that case, the circuit amount is somewhat larger than that of this embodiment.
以上説明したように、本発明によれば、ガロア体上の元
の指数表現からベクトル表現への変換を、演算により実
現するようにしたので、両表現を対応させたテーブルを
利用する場合に比して、小さな回路規模で、この変換を
行うことができるという効果がある。As described above, according to the present invention, since the conversion from the original exponential expression on the Galois field to the vector expression is realized by the operation, it is possible to compare with the case where the table in which both expressions are associated is used. Then, there is an effect that this conversion can be performed with a small circuit scale.
第1図は本発明の実施例に係る指数・ベクトル変換回路
のブロツク図、第2図は第1図のブロツク図の動作タイ
ミングチヤート、第3図は指数/ベクトル回路の構成を
示す図である。 1……指数/ベクトル回路 2……乗算回路 3……レジスタFIG. 1 is a block diagram of an exponent / vector conversion circuit according to an embodiment of the present invention, FIG. 2 is an operation timing chart of the block diagram of FIG. 1, and FIG. 3 is a diagram showing a structure of an exponent / vector circuit. . 1 ... Exponent / vector circuit 2 ... Multiplication circuit 3 ... Register
Claims (1)
意の元αnについて、指数表現を n=2m-1・Nm-1+2m-2・Nm-2+・・・+2・N1+N0 とするとき、入力されるNi(i=0,1,・・・,m−1)が
1のときにαの2i乗を出力し、0のときに1を出力する
論理回路手段と、 記憶手段と、 該記憶手段の記憶内容と前記論理回路手段からの出力と
を乗算する乗算手段と、 該乗算手段の乗算結果を前記記憶手段に更新記憶するよ
うに制御する制御手段とを具え、前記論理回路手段にNi
(i=0,1,・・・,m−1)を順次入力して、前記元αn
のベクトル表現を生成することを特徴とするガロア体上
の元の表現形式変換回路。1. An exponential expression for an arbitrary element α n on a Galois field GF (2 m ) with α as a primitive element is expressed as n = 2 m-1 · N m-1 +2 m-2 · N m-2. + ... + 2 · N 1 + N 0 , when the input N i (i = 0,1, ..., m−1) is 1, α 2 i is output and 0 Sometimes a logic circuit means for outputting 1; a storage means; a multiplication means for multiplying the stored contents of the storage means by the output from the logic circuit means; and a multiplication result of the multiplication means updated and stored in the storage means. and control means for controlling to, N i to the logic circuit means
(I = 0,1, ..., m-1) are sequentially input, and the element α n
An original representation format conversion circuit on a Galois field characterized by generating a vector representation of.
Priority Applications (9)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP61232003A JPH0783277B2 (en) | 1986-09-30 | 1986-09-30 | Original representation format conversion circuit on Galois field |
EP87308648A EP0262944B1 (en) | 1986-09-30 | 1987-09-29 | Error correction apparatus |
DE3789266T DE3789266T2 (en) | 1986-09-30 | 1987-09-29 | Error correction device. |
EP93201798A EP0566215B1 (en) | 1986-09-30 | 1987-09-29 | Error correction apparatus |
DE3751958T DE3751958T2 (en) | 1986-09-30 | 1987-09-29 | Error correction device |
DE3752367T DE3752367T2 (en) | 1986-09-30 | 1987-09-29 | Error correction unit |
EP96200874A EP0723342B1 (en) | 1986-09-30 | 1987-09-29 | Error correction apparatus |
US08/400,521 US5590138A (en) | 1986-09-30 | 1995-03-07 | Error correction apparatus |
US08/701,327 US5774389A (en) | 1986-09-30 | 1996-08-23 | Error correction apparatus |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP61232003A JPH0783277B2 (en) | 1986-09-30 | 1986-09-30 | Original representation format conversion circuit on Galois field |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6386924A JPS6386924A (en) | 1988-04-18 |
JPH0783277B2 true JPH0783277B2 (en) | 1995-09-06 |
Family
ID=16932418
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP61232003A Expired - Fee Related JPH0783277B2 (en) | 1986-09-30 | 1986-09-30 | Original representation format conversion circuit on Galois field |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0783277B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5275398B2 (en) | 2011-03-28 | 2013-08-28 | 株式会社東芝 | Reed-Solomon decoder and receiver |
-
1986
- 1986-09-30 JP JP61232003A patent/JPH0783277B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPS6386924A (en) | 1988-04-18 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
LAPS | Cancellation because of no payment of annual fees |