WO2016175035A1

WO2016175035A1 - Encoding device and method, decoding device and method, and program

Info

Publication number: WO2016175035A1
Application number: PCT/JP2016/061987
Authority: WO
Inventors: 康生朝倉; 野田　誠
Original assignee: ソニーセミコンダクタソリューションズ株式会社
Priority date: 2015-04-27
Filing date: 2016-04-14
Publication date: 2016-11-03
Also published as: JP2016208401A

Abstract

The present feature pertains to an encoding device and method, a decoding device and method, and a program configured to make it possible to improve the performance of a DC-free code. An encoder encodes an information word into a code word having a multivalue degree of 4, an encoding ratio of 0.8, and a digital sum variation (DSV) of 8-32 at a minimum inter-symbol distance of 2. A decoder decodes a code word into an information word, the code word having a multivalue degree of 4, an encoding ratio of 0.8, and a DSV of 8-32 at a minimum inter-symbol distance of 2. The present feature is applicable, for example, to an encoding device for encoding a DC-free code, or a decoding device for decoding a DC-free code.

Description

Encoding apparatus and method, decoding apparatus and method, and program

The present technology relates to an encoding device and method, a decoding device and method, and a program, and more particularly, to an encoding device and method, a decoding device and method, and a program that improve the performance of a DC-free code.

When the transmitter and the receiver perform data communication via the communication path, the quality spectrum of the transmission signal in the communication path may be suppressed by controlling the frequency spectrum of the transmission signal. Among codes that perform such frequency spectrum control, there are many types of DC-free codes that suppress the low-frequency component by setting the DC component as null, and are widely used in communication systems, storage systems, and the like. For example, as an example of the binary DC-free code, there are a Manchester code used in the wireless standard Felica (registered trademark) and the like, and an 8B10B code used in USB 3.0 and Gigabit Ethernet (registered trademark).

Conventionally, as a means for speeding up communication without expanding the necessary bandwidth, a multi-value DC-free code having a codeword symbol value of three values (Ternary) or more has been proposed. For example, Patent Document 1 proposes an 8B6T DC-free code that encodes an 8-bit information word into a ternary 6-symbol codeword. Patent Document 2 discloses a 12B8QT DC-free code for converting a 12-bit information word into a 4-value (Quaternary) 8-symbol codeword, and a 14-bit information word as a 5-value (Quinary) 8-symbol. A 14B8QN DC-free code to be converted into a codeword is proposed.

JP 2011-41059 A Japanese Patent No. 5564896

By the way, the amount of information of signals transmitted in data communication is steadily increasing. Therefore, it is desired to realize a DC-free code with better performance.

Therefore, the present technology is intended to improve the performance of the DC free code.

The encoding device according to the first aspect of the present technology has a DSV (Digital Sum Variation) of 8 or more and 32 or less when the multi-level is 4, the coding rate is 0.8, and the minimum distance between symbols is 2. An encoder for encoding an information word into a code word is provided.

The code word can be 10 symbols and the information word can be 16 bits.

DSV can be set to 8.

The run length of the code sequence in which the code words are arranged can be 4 or less.

CDS (Codeword Digital Sum) of the codeword is set to −2, 0, or 2, and the encoder includes an RDS (Running Digital Sum) of the start point and end point of the codeword of the code sequence in which the codewords are arranged. Can be limited to -1 or 1.

The code word can be 5 symbols and the information word can be 8 bits.

DSV can be 10.

The run length of the code sequence in which the code words are arranged can be 6 or less.

The CDS of the code word is set to -3, -1, 1 or 3, and the encoder has the RDS of the start point and the end point of the code word of the code sequence in which the code words are arranged to be -2, -1 It can be limited to 1 or 2.

The encoding method according to the first aspect of the present technology is an information word including a code word having a DSV of 8 or more and 32 or less when the multilevel is 4, the coding rate is 0.8, and the minimum distance between symbols is 2. An encoding step of encoding.

The program according to the first aspect of the present technology encodes an information word into a code word having a DSV of 8 to 32 when the multi-level is 4, the coding rate is 0.8, and the minimum distance between symbols is 2. The computer is caused to execute a process including an encoding step.

The decoding device according to the second aspect of the present technology uses, as an information word, a codeword having a DSV of 8 or more and 32 or less when the multilevel is 4, the coding rate is 0.8, and the minimum distance between symbols is 2. A decoder for decoding is provided.

The code word can be 10 symbols and the information word can be 16 bits.

DSV can be set to 8.

The code word can be 5 symbols and the information word can be 8 bits.

DSV can be 10.

The decoding method according to the second aspect of the present technology uses a codeword having a DSV of 8 or more and 32 or less when the multilevel is 4, the coding rate is 0.8, and the minimum distance between symbols is 2 as an information word. A decoding step of decoding.

The program according to the second aspect of the present technology decodes a codeword having a DSV of 8 or more and 32 or less into an information word when the multilevel is 4, the coding rate is 0.8, and the minimum distance between symbols is 2. The computer is caused to execute a process including a decoding step.

In the first aspect of the present technology, an information word is encoded into a code word having a DSV of 8 or more and 32 or less when the multi-level is 4, the coding rate is 0.8, and the minimum distance between symbols is 2. Is done.

In the second aspect of the present technology, a code word having a DSV of 8 or more and 32 or less is decoded into an information word when the multi-level is 4, the coding rate is 0.8, and the minimum distance between symbols is 2. The

According to the first aspect or the second aspect of the present technology, the performance of the DC free code is improved.

It should be noted that the effects described here are not necessarily limited, and may be any of the effects described in the present disclosure.

It is a block diagram which shows the basic composition of the transmission system to which this technique is applied. It is a block diagram showing a 1st embodiment of a transmission system to which this art is applied. It is a figure which shows the 1st example of the state transition diagram for every symbol of an encoder. It is a figure which shows the 1st example of the state transition diagram for every codeword of an encoder. It is a figure which shows the 1st example of an encoding / decoding table. It is a figure which shows the 2nd example of an encoding / decoding table. It is a block diagram which shows 2nd Embodiment of the transmission system to which this technique is applied. It is a figure which shows the 2nd example of the state transition diagram for every symbol of an encoder. It is a figure which shows the 2nd example of the state transition diagram for every codeword of an encoder. It is a figure which shows the 3rd example of an encoding / decoding table. It is a figure which shows the 4th example of an encoding / decoding table. It is a figure which shows the 5th example of an encoding / decoding table. It is a figure which shows the 5th example of an encoding / decoding table. It is a figure which shows the 5th example of an encoding / decoding table. It is a figure which shows the 5th example of an encoding / decoding table. It is a figure which shows the 5th example of an encoding / decoding table. It is a figure which shows the 5th example of an encoding / decoding table. It is a figure which shows the 6th example of an encoding / decoding table. It is a figure which shows the 6th example of an encoding / decoding table. It is a figure which shows the 6th example of an encoding / decoding table. It is a figure which shows the 6th example of an encoding / decoding table. It is a figure which shows the 6th example of an encoding / decoding table. It is a figure which shows the 6th example of an encoding / decoding table. It is a block diagram which shows the structural example of a computer.

Hereinafter, modes for carrying out the present technology (hereinafter referred to as embodiments) will be described. The description will be given in the following order.
1. 1. Basic configuration of transmission system First Embodiment (Example of realizing a DC-free code of 16B10QT)
3. Second Embodiment (Example of realizing 8B5QT DC-free code)
4). Modified example

<1. Basic configuration of transmission system>
First, a basic configuration of a transmission system to which the present technology is applied will be described with reference to FIG.

The transmission system 1 in FIG. 1 is configured to include an encoder 11 and a decoder 12.

The encoder 11 encodes an input signal into an n-symbol codeword having a multilevel m in units of k-bit information words. The encoder 11 transmits a transmission signal including a code sequence in which encoded codewords are arranged to the decoder 12 via a communication path. Note that the communication path between the encoder 11 and the decoder 12 may be wired or wireless.

The decoder 12 decodes each codeword included in the transmission signal into the original k-bit information word. The decoder 12 outputs an output signal including data in which the decoded information words are arranged to a subsequent apparatus.

Note that a general communication system often has a processing system in units of 8 bits because one byte is 8 bits. Therefore, it is desirable to set the number of bits k of the information word to a multiple of 8.

Here, as an index for evaluating the performance of the encoder 11, for example, there are a coding rate, a DSV, a maximum run length, and the like.

The coding rate r is obtained by the following equation (1).

r = 1 / n × log _m 2 ^k (1)

For example, the coding rate of the 8B6T DC-free code of Patent Document 1 described above is 0.841. Also, the coding rate of the DC-free code of 12B8QT in Patent Document 2 described above is 0.75, and the coding rate of the DC-free code of 14B8QN is 0.754.

DSV is the difference between the maximum value and the minimum value of RDS, which is the sum of the symbol values of the code sequence, and is generally defined as in the following equation (2).

DSV = RDS _max -RDS _min (2)

RDS _max is the maximum value of RDS, and RDS _min is the minimum value of RDS.

DSV is one index indicating the degree of suppression of the low frequency component of the DC free code, and the lower the value, the lower the frequency component can be suppressed. Further, in order to make the DC component null, it is necessary to limit the RDS to be finite.

For example, the DSV of the 8B6T DC-free code of Patent Document 1 described above is 10. Further, the DSV of the DC free code of 12B8QT in Patent Document 2 described above is 18, and the DSV of the DC free code of 14B8QN is 20.

The DSV value of each DC-free code is a value calculated by normalizing the symbol value of the code word so that the minimum distance between symbols (hereinafter referred to as the minimum symbol point distance) is 2. . For example, when the minimum symbol point distance is set to 2, the symbol value of the quaternary code word is, for example, one of {−3, −1, +1, +3}. By this normalization process, it is possible to compare DSVs of codes having different multilevel values on the same basis.

The maximum run length is the maximum value of the number of consecutive identical symbols (same value symbols) in the code sequence. For example, when the maximum number of consecutive identical symbols within one codeword is N, the maximum run length is 2N. In many transmission lines, it is desirable to make the maximum run length as small as possible for symbol synchronization.

<2. First Embodiment>
Next, a first embodiment of the present technology will be described with reference to FIGS.

{Configuration example of transmission system 1a}
FIG. 2 shows a configuration example of a transmission system 1a that is the first embodiment of the transmission system to which the present technology is applied.

The transmission system 1a is configured to include an encoder 11a and a decoder 12a.

The encoder 11a encodes the input signal into a 10-symbol code word having a multi-level of 4 in units of 16-bit information words. The encoder 11a transmits a transmission signal including a code sequence in which encoded codewords are arranged to the decoder 12a via a communication path.

The decoder 12a decodes each codeword included in the transmission signal into the original 16-bit information word. The decoder 12a outputs an output signal including data in which the decoded information words are arranged to a subsequent apparatus.

In the following, it is assumed that the symbol value of the code word consists of four values {-3, -1, +1, +3}. Therefore, the distance between the minimum symbol points is 2.

{State transition of encoder 11a}
Next, an example of state transition of the encoder 11a will be described with reference to FIGS.

FIG. 3 shows an example of a state transition diagram for each symbol of the encoder 11a. Each circle in the state transition diagram indicates the internal state of the encoder 11a. The subscript value to the right of the letter S in each circle indicates the RDS value in that state. In this example, the maximum value of RDS is +4 and the minimum value is −4. Therefore, the DSV is 8.

In the following, each internal state is indicated using the RDS value. For example, an internal state where RDS is 0 is referred to as S ₀ , an internal state where RDS is ₊₁ is referred to as S _+1, and an internal state where RDS is ₋₁ is referred to as S ₋₁ .

Each arrow indicates a state transition when the symbol having the value indicated by the arrow is output. For example, when the internal state is S ₀ and the symbol value + 1 symbol is output, the internal state transitions to S _{+ 1} , and when the symbol value + 3 symbol is output, the internal state is S _{+ 3} . Transition. Also, for example, when the internal state is S ₀ , if a symbol value of −1 is output, the internal state transitions to S ₋₁ , and if a symbol value of −3 is output, the internal state is Transition to S- ₃ .

Here, in order to facilitate the configuration of the encoder 11a and the decoder 12a, an internal state (hereinafter referred to as a post-codeword output state) that the encoder 11a can take after the final symbol of each codeword is output. It is desirable to reduce the number of Therefore, the encoder 11a limits the post-codeword output state to two states, S _{+ 1} and S- ₁ .

FIG. 4 shows an example of a state transition diagram for each codeword of the encoder 11a when the post-codeword output state is limited to two states S _{+ 1} and S- ₁ . Each circle in the state transition diagram indicates a state after the code word output of the encoder 11a. Each arrow in FIG. 4 indicates a state transition when the code word of the CDS indicated by each arrow is output.

Here, CDS is the sum of the symbol values in the codeword. For example, when the code word is [−3, −1, −1,1, −1,1, −1,1, −1,3], the CDS is −2 (= −3-1−1 + 1−1 + 1). -1 + 1-1 + 3).

When the codeword output state is S _{+ 1} , the encoder 11a outputs a codeword with CDS of 0 or -2. When a codeword with CDS of 0 is output, the post-codeword output state remains S _{+ 1} , and when a codeword with CDS of −2 is output, the post-codeword output state transitions to S- ₁ . .

When the codeword output state is S- ₁ , the encoder 11a outputs a codeword with CDS of 0 or +2. When a codeword with CDS of 0 is output, the post-codeword output state remains S- ₁ , and when a codeword with CDS of -2 is output, the post-codeword output state transitions to S _{+ 1} . .

Therefore, a codeword with CDS of 0 is used when the post-codeword output state is both S _{+ 1} and S- ₁ . On the other hand, a codeword with CDS of +2 is used only when the post-codeword output state is S ₋₁ , and a codeword with CDS of −2 is used only when the post-codeword output state is S ₊₁ .

{Encoding / Decoding Table of Transmission System 1a}
FIGS. 5 and 6 show examples of encoding / decoding tables used in the transmission system 1a in order to realize the state transitions of FIGS.

The encoding / decoding table A in FIG. 5 shows the correspondence between information words 0 to 16371 and code words. Since the number is large, only the information words from 0 to 9 are shown in this figure.

Here, the internal state of the starting point of the encoding / decoding table A is the internal state of the encoder 11a before outputting the code word in the table, that is, the code after the previous code word is output. This is the state after word output. The internal state of the end point is the internal state of the encoder 11a after outputting the codeword in the table, that is, the state after output of the codeword after the codeword in the table is output.

The codewords in Table A are all codewords in which CDS is 0, the maximum value of RDS in the codeword is 3 or less, and the minimum value is −3 or more. The codewords in Table A are used when the post-codeword output states are both S _{+ 1} and S- ₁ .

6 shows the correspondence between information words 16372 to 65335 and codewords. In addition, since there are many numbers, in this figure, only the information words from 16372 to 16381 are shown.

The codeword in Table B is a codeword having CDS of 0 or −2, the maximum value of RDS in the codeword being 3 or less, and the minimum value of −4 or −5. The codeword in Table B is used only when the codeword output state is S _{+ 1} .

{Encoding method of encoder 11a}
Next, the encoding method of the encoder 11a will be described.

When the information word to be encoded is included in the table A, the encoder 11a outputs a code word corresponding to the information word in the encoding / decoding table A of FIG. For example, when the information word is 0, the output code word is [-3, 1, -1, 1, -1, 1, -1, 1, -1, 3].

In addition, when the information word to be encoded is included in the table B, the encoder 11a switches the codeword to be output according to the state after the codeword is output.

Specifically, when the post-codeword output state is S _{+ 1} , the encoder 11a uses the codeword corresponding to the information word when the internal state is S _{+ 1} in the encoding / decoding table B of FIG. Is output. For example, when the information word is 16372, the output code word is [−3, −1, −1,1, −1,1, −1,1, −1,3].

When the post-codeword output state is S ₋₁ , the encoder 11 a uses the symbol value of each codeword corresponding to the information word when the internal state is S ₊₁ in the encoding / decoding table B of FIG. Output a codeword with all polarities reversed. For example, when the information word is 16372, the output code word is [3, 1, 1, -1, 1, -1, 1, -1, 1, -3]. The CDS of the code word output at this time becomes +2 by inverting the polarity of each symbol value.

In this way, the encoder 11a generates a 16B10QT DC-free code. That is, the encoder 11a encodes the input signal into a 10-symbol codeword having a multilevel of 4 in units of 16-bit information words. Then, the encoder 11a transmits a transmission signal including a code sequence in which encoded codewords are arranged to the decoder 12a via a communication path.

{Decoding method of decoder 12a}
The decoder 12a searches the encoding / decoding table A in FIG. 5 and the encoding / decoding table B in FIG. 6 for a codeword that matches the codeword to be decoded. Then, when a matching code word is found, the decoder 12a outputs an information word corresponding to the code word.

For example, when the code word to be decoded is [-3, 1, -1, 1, -1, 1, -1, 1, -1, 3], the code word that matches the code word is It exists in the encoding / decoding table A of FIG. Then, 0 which is an information word corresponding to the code word is output.

On the other hand, when no matching codeword is found, the decoder 12a inverts all the polarities of the symbol values of the codeword. Next, the decoder 12a searches the encoding / decoding table B shown in FIG. Then, the decoder 12a outputs an information word corresponding to the code word that matches the code word after the polarity inversion.

For example, when the code word to be decoded is [3, 1, 1, -1, 1, -1, 1, -1, 1, -3], the code word after polarity inversion is [-3 , −1, −1, 1, −1, 1, −1, 1, −1, 3]. Exists. Then, 16372, which is an information word corresponding to the code word after polarity inversion, is output.

In this way, the decoder 12a decodes the 16B10QT DC-free code.

{About the performance of the encoder 11a}
Under the conditions shown in the state transition diagram of FIG. 3, the Shannon capacity is 0.856. On the other hand, in the above-described 16B10QT DC-free code, the number of bits of the information word k = 16 bits, the multilevel m of the code word m = 4, and the number of symbols n = 10. The rate r = 0.8. This is 0.94 times the theoretical limit indicated by the Shannon capacity. Further, this coding rate exceeds the coding rate of the above-described 8B6T DC-free code of Patent Document 1, and 12B8QT DC-free code and 14B8QN DC-free code of Patent Document 2.

Also, the number of bits of an information word that can be expressed by one symbol of a code word is 1.6 bits. This is approximately 1.07 times the 1.5 bits of the 12B8QT DC-free code of Patent Document 2, which has the same multivalue level of 4.

Furthermore, since the maximum value of RDS is +4 and the minimum value is -4, DSV = 8. This DSV is smaller than the DSV of the 8B6T DC-free code of Patent Document 1 and the 12B8QT DC-free code and 14B8QN DC-free code of Patent Document 2.

Note that the DSV can be set to a value larger than 8. Obviously, even if the DSV is larger than 8, the constraint condition is relaxed, and the coding rate of 0.8 can be realized. However, DSV is, for example, [3, 3, 3, 3, 3, -3, -3, -3, -3, -3] and [-3, -3, -3, -3, -3, When two

codewords

3, 3, 3, 3, 3] are used, the maximum is 32.

In addition, among the codewords that can be used when the post-codeword output state is S _{+ 1} , the number of codewords having the same symbol number of 1 (that is, the same symbol is not consecutive) is 13538 in total. Yes, less than the number of information words. On the other hand, among the codewords that can be used when the post-codeword output state is S _{+ 1} , the number of codewords in which the number of consecutive identical symbols is 2 or less is 69351 in total, which is larger than the number of information words . Therefore, the number of consecutive identical symbols in one codeword can be suppressed to 2 or less, and the maximum run length can be limited to 4.

As described above, a DC-free code with higher performance than the conventional DC-free code can be realized. Also, the DC-free code is a code that can be sufficiently configured with realistic hardware, and since the information word is 16 bits, it has high compatibility with existing systems. Therefore, it can be easily applied to various systems.

<3. Second Embodiment>
Next, a second embodiment of the present technology will be described with reference to FIGS.

{Configuration example of transmission system 1b}
FIG. 7 illustrates a configuration example of a transmission system 1b that is the second embodiment of the transmission system to which the present technology is applied.

The transmission system 1b is configured to include an encoder 11b and a decoder 12b.

The encoder 11b encodes the input signal into a 5-symbol codeword having a multilevel of 4 in units of 8-bit information words. The encoder 11b transmits a transmission signal including a code sequence in which encoded codewords are arranged to the decoder 12a via a communication path.

The decoder 12b decodes each codeword included in the transmission signal into the original information word. The decoder 12a outputs an output signal including data in which the decoded information words are arranged to a subsequent apparatus.

{State transition of encoder 11b}
Next, an example of state transition of the encoder 11b will be described with reference to FIGS.

FIG. 8 shows an example of a state transition diagram for each symbol of the encoder 11b by the same diagram as FIG. 3 described above.

When the state transition diagram of FIG. 8 is compared with the state transition diagram of FIG. 3, the difference is that S ₊₅ and S _-5 are added. Therefore, in this example, since the maximum value of RDS is +5 and the minimum value is −5, DSV is 10.

FIG. 9 shows an example of a state transition diagram for each codeword of the encoder 11b by the same diagram as FIG. 4 described above.

In this example, if the post-codeword output state of the nth codeword is S _{+ 1} or S- ₁ , the post-codeword output state of the n + 1th codeword is limited to S _{+ 2} or S- _2. , The post-codeword output state of the (n + 2) th codeword is limited to S _{+ 1} or S- ₁ .

When the codeword output state is S ₊₂ , the encoder 11b outputs a codeword having a CDS of −1 or −3. When a codeword with CDS of -1 is output, the post-codeword output state transitions to S _{+ 1,} and when a codeword with CDS of -3 is output, the post-codeword output state transitions to S- ₁ . To do.

When the codeword output state is S _{+ 1} , the encoder 11b outputs a codeword having a CDS of +1 or -3. When a codeword with CDS of +1 is output, the post-codeword output state transitions to S ₊₂ . When a codeword with CDS of −3 is output, the post-codeword output state transitions to S ₋₂ . .

When the codeword output state is S- ₁ , the encoder 11b outputs a codeword having a CDS of +3 or -1. When a codeword with CDS of +3 is output, the post-codeword output state transitions to S ₊₂ . When a codeword with CDS of −1 is output, the post-codeword output state transitions to S ₋₂ . .

When the post-codeword output state is S- ₂ , the encoder 11b outputs a codeword with CDS of +3 or +1. When a codeword with CDS of +3 is output, the post-codeword output state transitions to S _{+ 1,} and when a codeword with CDS of +1 is output, the post-codeword output state transitions to S- ₁ .

Therefore, a codeword with CDS of +3 is used when the post-codeword output state is S ₋₁ and S ₋₂ . Codewords with CDS of +1 are used when the post-codeword output states are S _{+ 1} and S- ₂ . Codewords with CDS −1 are used when the post-codeword output states are S ₊₂ and S ₋₁ . Codewords with CDS of -3 are used when the post-codeword output states are S ₊₂ and S ₊₁ .

In the state transition diagram of FIG. 8, the initial value of the post-codeword output state may be set to any of S ₊₂ , S ₊₁ , S ₋₁ , and S ₋₂ .

{Encoding / Decoding Table of Transmission System 1b}
10 to 23 show examples of encoding / decoding tables used in the transmission system 1b in order to realize the state transition of FIGS. In this example, the information word is written in octal and the code word is written in decimal.

The encoding / decoding table C in FIG. 10 shows the correspondence between 0 to 5 information words and code words.

The codeword in Table C is a codeword in which CDS is −3, the maximum value of RDS in the codeword is 4, and the minimum value is −6 or more. The codeword in Table C is used when the post-codeword output state is S _{+ 1} .

11 shows a correspondence relationship between information words 6 to 23 and code words.

The codeword in Table D is a codeword having CDS of +1, the maximum value of RDS in the codeword being 4 or less, and the minimum value being −4, −5, or −6. The codeword in Table D is used when the post-codeword output state is S _{+ 1} .

The encoding / decoding table E in FIGS. 12 to 17 shows the correspondence between information words 24 to 140 and code words.

The codeword in Table E is a codeword having a CDS of +1, a maximum value of RDS in the codeword of 4 or less, and a minimum value of -3 or more. The codeword in Table E is used when the post-codeword output state is S _{+ 1} or S- ₂ .

The encoding / decoding table F in FIGS. 18 to 23 shows the correspondence between the information words 141 to 255 and the code words.

The codeword in Table F is a codeword having a CDS of −3, a maximum value of RDS in the codeword of 3 or less, and a minimum value of −6 or more. The codeword in Table F is used when the post-codeword output state is S _{+ 1} or S _{+ 2} .

{Encoding method of encoder 11b}
Next, the encoding method of the encoder 11b will be described.

When the information word to be encoded is included in the table C, the encoder 11b switches the codeword to be output according to the post-codeword output state.

Specifically, when the post-codeword output state is S _{+ 1} , the encoder 11b outputs a codeword corresponding to the information word in the encoding / decoding table C of FIG. For example, when the information word is 0, the output code word is [-3, -3, -1, 1, 3].

When the codeword output state is S ₋₁ , the encoder 11b determines the symbol value of each codeword corresponding to the information word when the internal state is S _{+ 1} in the encoding / decoding table C of FIG. Output a codeword with all polarities reversed. For example, when the information word is 0, the output code word is [3, 3, 1, −1, −3]. The CDS of the code word output at this time becomes +3 by inverting the polarity of each symbol value.

When the codeword output state is S _{+ 1} , the encoder 11b reverses the symbols of the codeword corresponding to the information word when the internal state is S _{+ 1} in the encoding / decoding table C of FIG. The codewords rearranged in are output. For example, when the information word is 0, the output code word is [3, 1, -1, -3, -3].

When the codeword output state is S- ₂ , the encoder 11b reverses the symbols of the codeword corresponding to the information word when the internal state is S _{+ 1} in the encoding / decoding table C of FIG. And a code word in which the polarity of each symbol value is reversed. For example, when the information word is 0, the output code word is [−3, −1,1,3,3]. The CDS of the code word output at this time becomes +3 by inverting the polarity of each symbol value.

In addition, when the information word to be encoded is included in the table D, the encoder 11b switches the code word to be output according to the state after the code word is output.

Specifically, when the post-codeword output state is S _{+ 1} , the encoder 11b outputs a codeword corresponding to the information word in the encoding / decoding table D of FIG. For example, when the information word is 6, the output code word is [-1, 3, 3, -3, -1].

When the codeword output state is S ₋₁ , the encoder 11b determines the symbol value of each codeword corresponding to the information word when the internal state is S _{+ 1} in the encoding / decoding table D of FIG. Output a codeword with all polarities reversed. For example, when the information word is 6, the output code word is [1, -3, -3, 3, 1]. The CDS of the code word output at this time becomes −1 by inverting the polarity of each symbol value.

When the codeword output state is S ₊₂ , the encoder 11b reverses the symbols of the codeword corresponding to the information word when the internal state is S _{+ 1} in the encoding / decoding table D of FIG. And a code word in which the polarity of each symbol value is reversed. For example, when the information word is 6, the output code word is [1, 3, −3, −3, 1]. The CDS of the code word output at this time becomes +3 by inverting the polarity of each symbol value.

When the codeword output state is S- ₂ , the encoder 11b reverses the symbols of the codeword corresponding to the information word when the internal state is S _{+ 1} in the encoding / decoding table D of FIG. The codewords rearranged in are output. For example, when the information word is 6, the output code word is [-1, -3, 3, 3, -1].

In addition, when the information word to be encoded is included in the table E, the encoder 11b switches the code word to be output according to the state after the code word is output.

Specifically, when the codeword output state is S _{+ 1} or S- ₂ , the encoder 11b outputs a codeword corresponding to the information word in the encoding / decoding table E of FIGS. To do. For example, when the information word is 24, the output code word is [-3, 1, -1, 1, 3].

When the codeword output state is S ₊₂ or S ₋₁ , the encoder 11b receives the information when the internal state is S ₊₁ or S ₋₂ in the encoding / decoding table E of FIGS. 12 to 17. A code word in which the polarity of each symbol value of the code word corresponding to the word is reversed is output. For example, when the information word is 24, the output code word is [3, -1, 1, -1, -3]. The CDS of the code word output at this time becomes −1 by inverting the polarity of each symbol value.

Furthermore, when the information word to be encoded is included in the table F, the encoder 11b switches the codeword to be output according to the state after the codeword is output.

Specifically, when the codeword output state is S ₊₂ or S _{+ 1} , the encoder 11b outputs a codeword corresponding to the information word in the encoding / decoding table F of FIGS. To do. For example, when the information word is 141, the output code word is [-3, -3, 1, -1, 3].

When the codeword output state is S ₋₁ or S ₋₂ , the encoder 11b performs the information when the internal state is S ₊₂ or S ₊₁ in the encoding / decoding table F of FIGS. A code word in which the polarity of each symbol value of the code word corresponding to the word is reversed is output. For example, when the information word is 141, the output code word is [3, 3, -1, 1, -1]. The CDS of the code word output at this time becomes +3 by inverting the polarity of each symbol value.

In this way, the encoder 11b generates an 8B5QT DC-free code. That is, the encoder 11b encodes the input signal into a 5-symbol codeword having a multi-level of 4 in units of 8-bit information words. Then, the encoder 11b transmits a transmission signal including a code sequence in which encoded codewords are arranged to the decoder 12b via a communication path.

{Decoding method of the decoder 12b}
The decoder 12b searches the encoding / decoding tables C to F for a code word that matches the code word to be decoded. Then, when a matching code word is found, the decoder 12b outputs an information word corresponding to the code word.

For example, when the code word to be decoded is [-3, -3, -1, 1, 3], a code word that matches the code word exists in the encoding / decoding table C in FIG. . Then, 0 which is an information word corresponding to the code word is output.

On the other hand, when no matching codeword is found, the decoder 12b inverts the polarity of each symbol value of the codeword. Next, the decoder 12b searches the encoding / decoding tables C to F for a code word that matches the code word after the polarity inversion. Then, the decoder 12b outputs an information word corresponding to the code word that matches the code word after the polarity inversion.

For example, when the codeword to be decoded is [1, -3, -3, 3, 1], there is no matching codeword in the encoding / decoding tables C to F. On the other hand, codewords that match the codewords [−1, 3, 3, −3, −1] after polarity inversion exist in the encoding / decoding table D of FIG. Then, 6 which is an information word corresponding to the code word is output.

Also, when the codeword after polarity inversion does not find a matching codeword, the decoder 12b rearranges the symbols of the codeword in reverse order. Next, the decoder 12b searches the encoding / decoding tables C to D for a code word that matches the code word after the reverse order rearrangement. Then, the decoder 12b outputs an information word corresponding to the code word that matches the code word after the reverse order rearrangement.

For example, when the codeword to be decoded is [-1, -3, 3, 3, -1], there is no matching codeword in the encoding / decoding tables C to F. Further, there is no code word in the encoding / decoding tables C to F that matches the code word [1, 3, −3, −3, 1] after polarity inversion. On the other hand, codewords that coincide with [−1, 3, 3, −3, −1] that are codewords after the reverse order are present in the encoding / decoding table D of FIG. Then, 6 which is an information word corresponding to the code word is output.

Furthermore, when a codeword that matches both the codeword after polarity reversal and the codeword after reverse order rearrangement is not found, the decoder 12b rearranges each symbol of the codeword in reverse order, and further, Invert all polarities. Next, the decoder 12b searches the encoding / decoding tables C to D for codewords that match the codewords after the reverse order rearrangement and polarity inversion. Then, the decoder 12b outputs an information word corresponding to a code word that matches the code word after reverse order rearrangement and polarity inversion.

For example, when the codeword to be decoded is [1, 3, −3, −3, 1], there is no matching codeword in the encoding / decoding tables C to F. Also, there is no code word in the encoding / decoding tables C to F that matches the code word [−1, −3, 3, 3, −1] after polarity inversion. Further, there is no code word in the encoding / decoding tables C to D that matches the code word [1, -3, -3, 3, 1] which is the code word after the reverse order rearrangement. On the other hand, codewords that coincide with [−1, 3, 3, −3, −1], which are codewords after reverse sorting and polarity reversal, exist in the encoding / decoding table D of FIG. Then, 6 which is an information word corresponding to the code word is output.

In this way, the decoder 12b decodes the 8B5QT DC-free code.

{About the performance of the encoder 11b}
Under the conditions shown in the state transition diagram of FIG. 8, the Shannon capacity is 0.897. On the other hand, in the above-described 8B5QT DC-free code, the number of bits of the information word k = 8 bits, the multilevel m = 4 of the code word, and the number of symbols n = 10. The rate r = 0.8. This is 0.89 times the theoretical limit indicated by the Shannon capacity. Further, this coding rate exceeds the coding rate of the above-described 8B6T DC-free code of Patent Document 1, and 12B8QT DC-free code and 14B8QN DC-free code of Patent Document 2.

Furthermore, since the maximum value of RDS is +5 and the minimum value is -5, DSV = 10. This DSV is the same value as the 8B6T DC-free code of Patent Document 1 described above, and is smaller than the DSV of the 12B8QT DC-free code and 14B8QN DC-free code of Patent Document 2.

Note that the 8B5QT DC-free code of the second embodiment has a higher DSV than the 16B10QT DC-free code of the first embodiment. However, since the number of bits of the information word is halved, the circuit scale of the encoder 11b and the decoder 12b can be significantly reduced as compared with the encoder 11a and the decoder 12a.

It is also possible to set the DSV to a value greater than 10. It is obvious that even if the DSV is larger than 10, the constraint condition is relaxed and a coding rate of 0.8 can be realized. However, the maximum DSV is 16, for example, when two codewords [3, 3, 1, -3, -3] and [-3, -3, -1, 3, 3] are used.

In addition, among the codewords that can be used when the post-codeword output state is S _{+ 1} , the number of codewords in which the number of consecutive identical symbols is 2 or less is 237 in total, which is smaller than the number of information words . On the other hand, among the codewords that can be used when the post-codeword output state is S _{+ 1} , the number of codewords in which the number of consecutive identical symbols is 3 or less is 260 in total, which is larger than the number of information words . Therefore, the number of consecutive identical symbols in one codeword can be suppressed to 3 or less, and the maximum run length can be limited to 6.

<4. Modification>
Hereinafter, modifications of the above-described embodiment of the present technology will be described.

The combination of the information word and the code word in the encoding / decoding table described above is an example, and can be freely changed within a range in which the performance of the DC free code described above can be secured. For example, the CDS of the codeword of the encoding / decoding table B in FIG. 6 may be designed to be 0 or +2. For example, the CDS of the codewords in the encoding / decoding table E in FIG. For example, the CDS of the code word E in the encoding / decoding table F in FIG. 12 may be designed to be all +3.

Further, the above-described state transition diagram is an example, and can be freely changed within a range in which the performance of the above-described DC-free code can be secured.

{Example of computer configuration}
The series of processes described above can be executed by hardware or can be executed by software. When a series of processing is executed by software, a program constituting the software is installed in the computer. Here, the computer includes, for example, a general-purpose personal computer capable of executing various functions by installing various programs by installing a computer incorporated in dedicated hardware.

FIG. 13 is a block diagram showing an example of the hardware configuration of a computer that executes the above-described series of processing by a program.

In the computer, a CPU (Central Processing Unit) 201, a ROM (Read Only Memory) 202, and a RAM (Random Access Memory) 203 are connected to each other by a bus 204.

An input / output interface 205 is further connected to the bus 204. An input unit 206, an output unit 207, a storage unit 208, a communication unit 209, and a drive 210 are connected to the input / output interface 205.

The input unit 206 includes a keyboard, a mouse, a microphone, and the like. The output unit 207 includes a display, a speaker, and the like. The storage unit 208 includes a hard disk, a nonvolatile memory, and the like. The communication unit 209 includes a network interface and the like. The drive 210 drives a removable medium 211 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.

In the computer configured as described above, the CPU 201 loads, for example, the program stored in the storage unit 208 to the RAM 203 via the input / output interface 205 and the bus 204 and executes the program. Is performed.

The program executed by the computer (CPU 201) can be provided by being recorded in the removable medium 211 as a package medium or the like, for example. The program can be provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

In the computer, the program can be installed in the storage unit 208 via the input / output interface 205 by attaching the removable medium 211 to the drive 210. The program can be received by the communication unit 209 via a wired or wireless transmission medium and installed in the storage unit 208. In addition, the program can be installed in the ROM 202 or the storage unit 208 in advance.

The program executed by the computer may be a program that is processed in time series in the order described in this specification, or in parallel or at a necessary timing such as when a call is made. It may be a program for processing.

In this specification, the system means a set of a plurality of components (devices, modules (parts), etc.), and it does not matter whether all the components are in the same housing. Accordingly, a plurality of devices housed in separate housings and connected via a network and a single device housing a plurality of modules in one housing are all systems. .

Furthermore, embodiments of the present technology are not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present technology.

For example, the present technology can take a cloud computing configuration in which one function is shared by a plurality of devices via a network and is jointly processed.

Further, the effects described in the present specification are merely examples and are not limited, and other effects may be obtained.

Also, for example, the present technology can take the following configurations.

(1)
An encoder that encodes an information word into a code word having a DSV (Digital Sum Variation) of 8 or more and 32 or less when the multilevel is 4, the coding rate is 0.8, and the minimum distance between symbols is 2. An encoding device provided.
(2)
The codeword is 10 symbols,
The encoding word according to (1), wherein the information word is 16 bits.
(3)
The encoding apparatus according to (2), wherein the DSV is 8.
(4)
The encoding device according to (3), wherein a run length of a code sequence in which the codewords are arranged is 4 or less.
(5)
CDS (Codeword Digital Sum) of the codeword is −2, 0, or 2,
The encoder restricts the RDS (Running Digital Sum) at the start point and end point of the code word of the code sequence in which the code words are arranged to −1 or 1, according to any one of the above (2) to (4) The encoding device described.
(6)
The codeword is 5 symbols,
The information word is 8 bits. The encoding apparatus according to (1).
(7)
DSV is 10. Encoding apparatus as described in said (6).
(8)
The encoding device according to (7), wherein a run length of a code sequence in which the codewords are arranged is 6 or less.
(9)
The CDS of the codeword is -3, -1, 1 or 3;
The encoder restricts the RDS of the start point and end point of the code word of the code sequence in which the code words are arranged to -2, -1, 1 or 2, according to any one of (6) to (8) The encoding device described.
(10)
An encoding method including an encoding step of encoding an information word into a code word having a DSV of 8 or more and 32 or less when the multilevel is 4, the coding rate is 0.8, and the minimum distance between symbols is 2.
(11)
When the multi-level is 4, the coding rate is 0.8, and the minimum distance between symbols is 2, a process including an encoding step for encoding an information word into a code word having a DSV of 8 or more and 32 or less is performed on a computer. A program to be executed.
(12)
A decoding apparatus comprising: a decoder that decodes a codeword having a DSV of 8 or more and 32 or less into an information word when the multi-level is 4, the coding rate is 0.8, and the minimum distance between symbols is 2.
(13)
The codeword is 10 symbols,
The decoding device according to (12), wherein the information word is 16 bits.
(14)
The decoding device according to (13), wherein the DSV is 8.
(15)
The decoding device according to (14), wherein a run length of a code sequence in which the codewords are arranged is 4 or less.
(16)
The codeword is 5 symbols,
The decoding device according to (12), wherein the information word is 8 bits.
(17)
The decoding device according to (16), wherein the DSV is 10.
(18)
The decoding device according to (17), wherein a run length of a code sequence in which the codewords are arranged is 6 or less.
(19)
A decoding method comprising: a decoding step of decoding a code word having a DSV of 8 or more and 32 or less into an information word when the multi-level is 4, the coding rate is 0.8, and the minimum distance between symbols is 2.
(20)
Let the computer execute a process including a decoding step of decoding a codeword having a DSV of 8 or more and 32 or less into an information word when the multi-level is 4, the coding rate is 0.8, and the minimum distance between symbols is 2. Program for.

1, 1a, 1b transmission system, 11, 11a, 11b encoder, 12, 12a, 12b decoder

Claims

An encoder that encodes an information word into a code word having a DSV (Digital Sum Variation) of 8 or more and 32 or less when the multilevel is 4, the coding rate is 0.8, and the minimum distance between symbols is 2. An encoding device provided.
The codeword is 10 symbols,
The encoding apparatus according to claim 1, wherein the information word is 16 bits.
The encoding device according to claim 2, wherein the DSV is 8.
The encoding apparatus according to claim 3, wherein a run length of a code sequence in which the code words are arranged is 4 or less.
CDS (Codeword Digital Sum) of the codeword is −2, 0, or 2,
3. The encoding device according to claim 2, wherein the encoder limits an RDS (Running Digital Sum) of a start point and an end point of the code word of a code sequence in which the code words are arranged to −1 or 1. 4.
The codeword is 5 symbols,
The encoding apparatus according to claim 1, wherein the information word is 8 bits.
The encoding apparatus according to claim 6, wherein the DSV is 10. 7.
The encoding apparatus according to claim 7, wherein a run length of a code sequence in which the code words are arranged is 6 or less.
The CDS of the codeword is -3, -1, 1 or 3;
The encoding device according to claim 6, wherein the encoder limits RDSs of the start point and end point of the code word of the code sequence in which the code words are arranged to -2, -1, 1 or 2.
An encoding method including an encoding step of encoding an information word into a code word having a DSV of 8 or more and 32 or less when the multilevel is 4, the coding rate is 0.8, and the minimum distance between symbols is 2.
When the multi-level is 4, the coding rate is 0.8, and the minimum distance between symbols is 2, a process including an encoding step for encoding an information word into a code word having a DSV of 8 or more and 32 or less is performed on a computer. A program to be executed.
A decoding apparatus comprising: a decoder that decodes a codeword having a DSV of 8 or more and 32 or less into an information word when the multi-level is 4, the coding rate is 0.8, and the minimum distance between symbols is 2.
The codeword is 10 symbols,
The decoding device according to claim 12, wherein the information word is 16 bits.
The decoding device according to claim 13, wherein the DSV is 8.
The decoding device according to claim 14, wherein a run length of a code sequence in which the codewords are arranged is 4 or less.
The codeword is 5 symbols,
The decoding device according to claim 12, wherein the information word is 8 bits.
The decoding device according to claim 16, wherein the DSV is 10.
The decoding device according to claim 17, wherein a run length of a code sequence in which the codewords are arranged is 6 or less.
A decoding method comprising: a decoding step of decoding a code word having a DSV of 8 or more and 32 or less into an information word when the multi-level is 4, the coding rate is 0.8, and the minimum distance between symbols is 2.
Let the computer execute a process including a decoding step of decoding a codeword having a DSV of 8 or more and 32 or less into an information word when the multi-level is 4, the coding rate is 0.8, and the minimum distance between symbols is 2. Program for.