CN101764617B - Coding method of 9B/10B code - Google Patents

Abstract

The invention discloses a coding method of a 9B/10B code, comprising the following steps: dividing a 9bit codeword into three code segments, and performing mapping to obtain a negative polarity 10bit codeword; calculating the unbalance degree of the negative polarity 10bit codeword, And calculate the positive polarity 10bit code word according to the unbalance degree; calculate the polarity of the current channel code stream, and select the negative polarity 10bit code word or the positive polarity 10bit code word output according to the polarity to achieve DC balance. The method utilizes the jump of positive and negative polarity deviations to realize the direct current control of encoding, and has the advantages of high encoding efficiency and good direct current characteristics.

Description

A Coding Method of 9B/10B Code

technical field

The invention relates to the technical field of communication, in particular to a coding method of a 9B/10B code, which has a DC equalization characteristic.

Background technique

With the rapid development of communication technology, the rate and data volume of data transmission have been greatly improved, so higher requirements are put forward for the reliability of data transmission. Due to the increase of the transmission distance and the increase of the transmission rate, the signal attenuation becomes very serious, and the waveform is also prone to obvious distortion, which leads to a significant decline in data reliability. In order to increase the reliability and stability of data transmission, it is necessary to code and modulate the digital signal to match the signal spectrum with the transmission medium, so as to realize the full utilization of the transmission medium.

Compared with ordinary wired communication systems, optical fiber digital transmission systems have the advantages of low loss, wide bandwidth, low electromagnetic interference and high security, and are more and more used in communication systems. The mB/nB modulation code is the most commonly used code in optical fiber digital transmission systems. It is essentially a block code. A mapping rule with high coding speed and efficiency can be preset according to the requirements of transmission characteristics. It is suitable for hardware implementation. The mB/nB modulation code has the advantages of better signal spectrum characteristics, small baseline drift, and low bit error rate.

The main principle of mB/nB encoding is to group the input binary original code stream, and each group has m binary codes, denoted as mB, which is called a codeword, and then transforms a codeword into n binary codes, denoted as nB, and output in the same time slot. Both m and n are positive integers, n>m, generally select n=m+1, among them, 1B/2B, 2B/3B, 3B/4B, etc. are mainly used in low-speed optical fiber digital transmission, 5B/6B, 5B/7B, 6B/8B, 7B/8B, etc. are mainly used in high-speed optical fiber digital transmission, but the highest can only reach hundreds of megabits/s, which still cannot meet the needs of actual transmission.

At present, Gigabit Ethernet of the 1000BASE-X standard mainly adopts 8B/10B modulation codes with small transmission bandwidth, high conversion density, limited code word run length and DC balance characteristics. However, the coding efficiency of the 8B/10B modulation code is only 80%, and there is still a need to further improve the coding efficiency in high-speed data transmission systems. However, the 9B/10B modulation code with relatively high coding efficiency is difficult to implement in hardware due to the complicated coding process and large amount of calculation. Currently, its application in the field of optical fiber transmission is limited.

Contents of the invention

Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a 9B/10B coding method with higher coding efficiency and simple coding process.

In order to achieve the above object, the present invention provides a coding method of 9B/10B code, comprising the following steps: dividing the 9bit codeword into three code segments, and performing mapping to obtain the negative polarity 10bit codeword; calculating the negative polarity 10bit codeword According to the unbalance degree, calculate the positive polarity 10bit code word; calculate the polarity of the current channel code stream, and select the negative polarity 10bit code word or the positive polarity 10bit code word output according to the polarity to achieve DC balance.

The beneficial effect of the present invention is that the method adopts the encoding method of 9B/10B code, and its theoretical encoding efficiency can be as high as 90%, which has the advantage of high encoding efficiency. During the encoding process, the code word is divided into three code segments for classification and mapping, which can greatly simplify the 9B/10B code table generation process, effectively improve the encoding speed, and facilitate the hardware implementation of the 9B/10B codec. In addition, this method also uses the jump of positive and negative polarity deviation to realize the DC control of the encoding, and try to choose the codeword with short run length in the process of code table design, which has the advantages of high encoding efficiency, good DC characteristics, and short run length. advantage.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, wherein:

Fig. 1 is the flow chart of the coding method of 9B/10B code according to the embodiment of the present invention;

Fig. 2 is a schematic diagram of the process of code word mapping in the coding method of 9B/10B code according to the embodiment of the present invention; And

Fig. 3 is a schematic diagram of a process of updating the polarity of a channel code stream in a coding method of a 9B/10B code according to an embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

FIG. 1 shows a general flow of a method for encoding a 9B/10B code according to an embodiment of the present invention. The main steps of the encoding method of the 9B/10B code are: first divide the 9bit codeword into three code segments, and map to obtain the negative polarity 10bit codeword; then calculate the unbalance degree of the negative polarity 10bit codeword, and according to different The balance degree calculates the positive polarity 10bit codeword; finally calculates the polarity of the current channel code stream, and selects the negative polarity 10bit codeword or the positive polarity 10bit codeword output according to the polarity to achieve DC balance. The specific operation of each step is as follows:

S1: Divide the 9-bit codeword into three code segments, and perform mapping to obtain a negative polarity 10-bit codeword.

FIG. 2 shows a general process of codeword mapping in the encoding method of 9B/10B code according to the embodiment of the present invention. Combining Figure 1 and Figure 2, it can be seen that in step S1, the 9-bit code word obtained by grouping the input data is firstly divided into three code segments with lengths of 4 bit, 1 bit and 4 bit and classified respectively, so as to classify each 9-bit code Words are classified; then the three code segments of the classified 9bit code word are mapped into three code segments of length 4bit, 2bit and 4bit respectively to form the negative polarity 10bit code word. Dividing the code word into three code segments can greatly simplify the code table generation and encoding process of the 9B/10B code, and it is also easy to realize the hardware of the 9B/10B codec.

S101: Divide the 9-bit codeword into three code segments with lengths of 4bit, 1bit and 4bit and classify them respectively, so as to classify the 9-bit codeword.

In step S101, the 9-bit code word X is first divided into a 4-bit first code segment X ₁ , a 1-bit second code segment X ₂ and a 4-bit third code segment X ₃ , the specific form is:

X＝X ₁ -X ₂ -X ₃ ＝[x ₈ x ₇ x ₆ x ₅ x ₄ x ₃ x ₂ x ₁ x ₀ ]

in

X ₁ =[x ₈ x ₇ x ₆ x ₅ ], X ₂ =[x ₄ ], X ₃ =[x ₃ x ₂ x ₁ x ₀ ]

Then divide the 4-bit information in the first code segment X ₁ and the third code segment X ₃ of the 9-bit codeword into 5 categories according to the number of "1" in the bit, and the number corresponding to "1" is 0 respectively , 1, 2, 3, 4, the 1bit information in the second code segment X ₂ is divided into 2 types according to the states of "1" and "0" in the bits, and the corresponding states are 1 and 0 respectively, so that the 9bit code Words are divided into 5*2*5=50 categories. For example, for a 9-bit codeword 1110-1-0101, its classification is 3-1-2.

S102: Map the three code segments of the classified 9-bit codeword into three code segments with lengths of 4 bits, 2 bits and 4 bits respectively, so as to form the negative polarity 10-bit code word.

In order to describe the coding mapping rules more clearly, in step S102, a method similar to step S101 may also be used to segment and classify each bit of the 10-bit codeword. Divide the 10-bit code word Y into a 4-bit first code segment Y ₁ , a 2-bit second code segment Y ₂ and a 4-bit third code segment Y ₃ , the specific form is:

Y=Y ₁ -Y ₂ -Y ₃ =[y ₉ y ₈ y ₇ y ₆ y ₅ y ₄ y ₃ y ₂ y ₁ y ₀ ]

in

Y ₁ =[y ₉ y ₈ y ₇ y ₆ ], Y ₂ =[y ₅ y ₄ ], Y ₃ =[y ₃ y ₂ y ₁ y ₀ ]

Then divide the 4-bit information in the first code segment Y ₁ and the third code segment Y ₃ of the 10bit codeword into 5 categories according to the number of "1" in the bit, and the number corresponding to "1" is 0 respectively , 1, 2, 3, 4, the 2bit information in the second code segment Y ₂ is divided into 4 categories according to the combined state of "1" and "0" in the bit, corresponding to the combined state of "1" and "0" are 00, 01, 10, and 11 respectively, so that the 10-bit codewords are divided into 5*4*5=100 categories. For example, for a 10-bit codeword 1111-01-0010, its classification is 4-01-1.

After the classification of 9bit codewords is completed, use the classification of 9bit codewords to select the corresponding mapping rules from the preset common codeword mapping rule modification table, common codeword mapping rule table and special codeword mapping rule table to perform 9bit codeword classification. map. Table 1 is a table for modifying common codeword mapping rules, Table 2 is a table for common codeword mapping rules, and Table 3 is a table for special codeword mapping rules. The mapping rules shown in Table 1, Table 2 and Table 3 are designed based on the principle of reducing the design complexity of 9B/10B codecs, and are easy to implement in hardware.

Table 1

source word([x ₈ ... x ₀ ]) codeword([y ₉ ... y ₀ ]) source word([x ₈ ... x ₀ ]) codeword([y ₉ ... y ₀ ]) 0001-1-1000 1110-11-1010 0001-1-1111 1101-11-1010 0011-1-1111 1011-11-1010 1111-1-0111 0111-11-1010

Table 2

X Y R X Y R X Y R X Y R X Y R 0-0-0 3-11-2 N ₁ 1-0-0 2-11-1 D ₁ 2-0-0 2-11-2 D ₁ 3-0-0 3-11-2 B ₁ 4- 0-0 3-11-2 N ₃ 0-1-0 3-11-2 N ₅ 1-1-0 2-11-1 D ₂ 2-1-0 2-11-2 D ₂ 3-1- 0 3-11-0 A ₁ 4-1-0 3-11-2 N ₇ 0-0-1 2-11-1 C ₁ 1-0-1 3-00-3 A ₄ 2-0-1 2-00-3 A ₂ 3-0-1 3-01-1 A ₁ 4- 0-1 2-11-1 C ₂ 0-1-1 2-11-1 C ₃ 1-1-1 1-11-3 A ₂ 2-1-1 2-11-3 A ₂ 3-1- 1 3-10-1 A ₁ 4-1-1 2-11-1 C ₄ 0-0-2 2-11-2 C ₁ 1-0-2 3-00-2 A ₃ 2-0-2 2-01-2 A ₁ 3-0-2 3-01-2 A ₁ 4- 0-2 2-11-2 C ₂ 0-1-2 2-11-2 C ₃ 1-1-2 1-11-2 A ₁ 2-1-2 2-10-2 A ₁ 3-1- 2 3-10-2 A ₁ 4-1-2 2-11-2 C ₄ 0-0-3 3-11-1 E ₁ 1-0-3 1-01-3 A ₁ 2-0-3 2-01-3 A ₁ 3-0-3 3-01-3 A ₁ 4- 0-3 3-11-1 E ₂ 0-1-3 3-11-1 E ₃ 1-1-3 1-10-3 A ₁ 2-1-3 2-10-3 A ₁ 3-1- 3 3-10-3 A ₁ 4-1-3 3-11-1 E ₄ 0-0-4 3-11-2 N ₂ 1-0-4 1-00-4 A ₁ 2-0-4 2-00-4 A ₁ 3-0-4 3-00-4 A ₁ 4- 0-4 3-11-2 N ₄ 0-1-4 3-11-2 N ₆ 1-1-4 1-10-4 A ₁ 2-1-4 2-10-4 A ₁ 3-1- 4 3-11-2 B ₂ 4-1-4 3-11-2 N ₈

table 3

source word([x ₈ ... x ₀ ]) codeword([y ₉ ... y ₀ ]) source word([x ₈ ... x ₀ ]) codeword([y ₉ ... y ₀ ]) 0111-1-1100 0111-11-1100 0001-1-1111 0001-10-1111 1110-1-1100 1110-11-1100 1101-1-1100 1101-11-1100 0011-1-1111 0011-10-1111 0111-1-1000 0111-11-1000 0001-1-0111 0001-11-0111 1011-1-1100 1011-11-1100

Since the code stream transmitted in the channel includes common codewords and special codewords with special functions such as frame synchronization, in order to avoid the common codewords being mistakenly matched into special codewords during the mapping process, the common codewords shown in Table 1 are specially formulated. Codeword mapping rule revision table. If the 9bit codeword is an ordinary codeword, first query Table 1, if the 9bit codeword can find the corresponding mapping rules in Table 1, then directly map according to the mapping rules in Table 1, otherwise follow the corresponding mapping in Table 2 rules for mapping. The specific meaning of the mapping rule R in Table 2 is as follows:

Mapping rule A ₁ : Y ₁ =X ₁ , Y ₃ =X ₃ , a total of 316 mappings;

Mapping rule A ₂ : Y ₁ =X ₁ , Y ₃ =-X ₃ (-X ₃ represents the inverse of X ₃ , the same below), a total of 64 mappings;

Mapping rule A ₃ : Y ₁ =-X ₁ , Y ₃ =X ₃ , 24 mappings in total;

Mapping rule A ₄ : Y ₁ =-X ₁ , Y ₃ =-X ₃ , 16 mappings in total;

Mapping rule B ₁ : Y ₁ =X ₁ , Y ₃ =[0011], 4 mappings in total;

Mapping rule B ₂ : Y ₁ =X ₁ , Y ₃ =[0101], 4 mappings in total;

Mapping rule C ₁ : Y ₁ =[0011], Y ₃ =X ₃ , 10 mappings in total;

Mapping rule C ₂ : Y ₁ =[0101], Y ₃ =X ₃ , 10 mappings in total;

Mapping rule C ₃ : Y ₁ =[0110], Y ₃ =X ₃ , 10 mappings in total;

Mapping rule C ₄ : Y ₁ =[1001], Y ₃ =X ₃ , 10 mappings in total;

Mapping rule D ₁ : Y ₁ =[1010], Y ₃ =X ₁ , 10 mappings in total;

Mapping rule D ₂ : Y ₁ =[1100], Y ₃ =X ₁ , 10 mappings in total;

Mapping rule E ₁ : Y ₁ =X ₃ , Y ₃ =[0001], 4 mappings in total;

Mapping rule E ₂ : Y ₁ =X ₃ , Y ₃ =[0010], 4 mappings in total;

Mapping rule E ₃ : Y ₁ =X ₃ , Y ₃ =[0100], 4 mappings in total;

Mapping rule E ₄ : Y ₁ =X ₃ , Y ₃ =[1000], 4 mappings in total;

Mapping rule N ₁ : Y ₁ =[0111], Y ₃ =[0110], a total of 1 mapping;

Mapping rule N ₂ : Y ₁ = [1011], Y ₃ = [0110], a total of 1 mapping;

Mapping rule N ₃ : Y ₁ =[1101], Y ₃ =[0110], a total of 1 mapping;

Mapping rule N ₄ : Y ₁ =[1110], Y ₃ =[0110], a total of 1 mapping;

Mapping rule N ₅ : Y ₁ =[0111], Y ₃ =[1001], a total of 1 mapping;

Mapping rule N ₆ : Y ₁ =[1011], Y ₃ =[1001], a total of 1 mapping;

Mapping rule N ₇ : Y ₁ =[1101], Y ₃ =[1001], a total of 1 mapping;

Mapping rule N ₈ : Y ₁ =[1110], Y ₃ =[1001], 1 mapping in total.

In the process of signal transmission, some special codewords for establishing synchronization, diagnosing line faults, controlling transmission status, etc. need to be added to improve the reliability of signal transmission. When the 9-bit codeword is a special codeword, it is mapped according to the mapping rules in Table 3.

After the mapping is completed through the above steps, the negative polarity 10-bit codeword corresponding to the input 9-bit codeword can be obtained. For example, for the code word 0110-1-0000 with a source of 9 bits, its classified value is 2-1-0, according to Table 2, the corresponding 10-bit code word value is 2-11-2 , the mapping rule is D ₂ , that is, Y ₁ =[1100], Y ₃ =X ₁ , so Y ₁ =[1100], Y ₂ =[11], Y ₃ =X ₁ =[0110], namely 9bit code The negative polarity 10-bit code word corresponding to the word 0110-1-0000 is 1100-11-0110.

S2: Calculate the unbalance degree of the negative polarity 10-bit codeword, and calculate the positive polarity 10-bit codeword according to the unbalance degree.

The unbalance degree of a 10bit codeword is defined as the difference between the number of "0" and the number of "1" in the 10bit codeword, that is, when the number of "0" is less than the number of "1", it is negative and equal When it is zero, it is positive when it is greater than.

After calculating the imbalance degree, if the imbalance degree is zero, the positive 10-bit codeword is the original code of the negative polarity 10-bit codeword; if the imbalance degree is not zero, the positive polarity 10-bit codeword is the inverse of the negative polarity 10-bit codeword code, so that the positive polarity 10-bit code words corresponding to all negative polarity 10-bit code words can be obtained.

For example, for a codeword K.0FCH with a source of 9 bits, K. indicates that the codeword is a special character, and H is a hexadecimal symbol. This codeword can be used for frame synchronization and is a special character, and its binary representation is 0111 -1-1100, look up table 3, we can know that the corresponding negative polarity 10bit code word is 0111-11-1100, the unbalance degree of this 10bit code word is -4, so the positive and negative polarity 10bit code corresponding to K.0FCH The words are inverse codes, that is, the positive polarity 10bit codeword is 1000-00-0011, thus the positive and negative polarity codewords corresponding to the 9bit codeword K.0FCH as the source are 0111-11-1100( negative) and 1000-00-0011 (positive).

For another example, for the code word D.038H of 9bit, D. represents that this code word is a common character, and its binary representation is 0001-1-1000, which belongs to the source word listed in Table 1, that is, D.038H is For the codeword that needs to be corrected, look up Table 1 to know that the corresponding negative polarity 10bit codeword is 1110-11-1010, and the unbalance degree of the 10bit codeword is -4, so the positive and negative polarity 10bit corresponding to D.038H The codewords are inverses of each other, that is, the positive polarity 10bit codeword is 0001-00-0101, and thus the positive and negative polarity codewords corresponding to the 9bit source word D.038H are 1110-11-1010 (negative) and 0001-00-0101 (positive).

For another example, for the codeword D.086H whose source is 9bit, the codeword is an ordinary character, and its binary representation is 0100-0-0110, which does not belong to the source words listed in Table 1. Look up Table 2 to know its corresponding The negative polarity 10bit codeword of D.086H is 1011-00-0110, and the unbalance degree of this 10bit codeword is 0, so the positive and negative polarity 10bit codewords corresponding to D.086H are the same, that is, the positive polarity 10bit codeword is also 1011- 00-0110, thus it can be obtained that the positive and negative polarity code words corresponding to the 9-bit source word D.086H are 1011-00-0110 (negative) and 1011-00-0110 (positive) respectively.

S3: Calculate the polarity of the current channel code stream, and select the negative polarity 10-bit code word or the positive polarity 10-bit code word to output according to the polarity, so as to realize DC balance.

Figure 3 shows the general process of updating the polarity of the channel code stream in the encoding method of the 9B/10B code according to an embodiment of the present invention, wherein RD ₁₀ represents the unbalance degree of the output 10bit code word, and RDS represents the channel code stream The total unbalance degree, the specific steps are as follows:

S301: Set the polarity of the channel code stream at the initial moment to be negative;

S302: Determine the polarity of the current channel code stream, if the polarity is negative, output a positive polarity 10-bit code word at the next moment, and if the polarity is positive, output a negative polarity 10-bit code word at the next moment;

S303: After outputting the 10-bit code word, calculate the total unbalance degree RDS of the channel code stream, and update the polarity of the channel code stream according to the total unbalance degree RDS, and proceed to step S302 again.

The total imbalance degree RDS of the channel code stream is defined as the sum of the imbalance degree RD ₁₀ of all output 10-bit code words from the initial moment to the current moment. After calculating the total unbalance degree RDS of the channel code stream at the current moment, if the total unbalance degree RDS is positive, the polarity of the channel code stream is updated to be positive; if the total unbalance degree RDS is negative, the polarity of the channel code stream is If the total unbalance degree RDS is zero, and the unbalance degree RD ₁₀ of the currently output 10bit codeword is zero, then the polarity of the channel code stream does not change; if the total unbalance degree RDS is zero, and If the unbalance degree RD ₁₀ of the currently output 10-bit codeword is not zero, the polarity of the channel code stream is reversed. Then, according to the polarity of the channel code stream, the polarity of the 10-bit code word that can be output at the next moment is selected.

According to the 9B/10B codeword mapping method, each 9bit source word corresponds to two 10bit codewords with positive and negative polarities. By selecting codeword outputs with different polarities, the characteristic of DC balance in the encoding process can be realized.

For example, the source codeword sequence to be encoded is as follows:

K.0FCH D.0FCH D.038H D.086H D.009H D.188H D.15EH D.03FH

Among them, K.0FCH is a special character for frame synchronization, and the rest are common characters. According to the above code word mapping rules, the positive and negative polarity 10-bit code words corresponding to each 9-bit source word are obtained, and then according to the process shown in Figure 3, DC equalization is performed on the code word sequence as the source to obtain 9B/10B code. The process is as follows:

9bit source word Negative polarity 10bit code word Positive polarity 10bit code word Channel code stream polarity before encoding output codeword Output codeword imbalance (RD ₁₀ ) Channel code stream total unbalance (RDS) Coded channel code stream polarity K.0FCH 0111-11-1100 1000-00-0011 burden 1000-00-0011 4 4 just D.0FCH 0111-10-1100 1000-01-0011 just 0111-10-1100 -2 2 just D.038H 1110-11-1010 0001-00-0101 just 1110-11-1010 -4 -2 burden D.086H 1011-00-0110 1011-00-0110 burden 1011-00-0110 0 -2 burden D.009H 0011-11-1001 1100-00-0110 burden 1100-00-0110 2 0 just D.188H 1100-00-0111 1100-00-0111 just 1100-00-0111 0 0 just D.15EH 1010-10-1110 0101-01-0001 just 1010-10-1110 -2 -2 burden D.03FH 1101-11-1010 0010-00-0101 burden 0010-00-0101 4 2 just

The codeword sequence output obtained after 9B/10B encoding is as follows:

10000000110111101100111011101010110001101100000110110000011110101011100010000101

According to the encoding method of the 9B/10B code in the embodiment of the present invention, the EP2C35F484I8 chip of Altera Company can be used to design the 9B/10B hardware encoder and decoder. The whole design is realized by Verilog HDL programming language. A total of 242 logic units are used in the simulation experiment, among which the encoder occupies 120 logic units, and the decoder occupies 122 logic units. The highest clock frequency of the system can reach 338MHz. In the encoding process of 9B/10B code, through the selection of 10bit code words, the code words that may cause long consecutive "0" or "1" are eliminated, and the source code word and target code are designed based on the principle of short run length priority The mapping rules between words finally realize the control of the run length of the channel code stream. The coding efficiency of this coding method can reach 90% in theory. Compared with the 8B/10B coding commonly used in the current high-speed serial data transmission, the coding efficiency is increased by 12.5%. up 12.5%. The method utilizes the jump of positive and negative polarity deviations to realize the direct current control of encoding, and has the advantages of high encoding efficiency and good direct current characteristics. Compared with the existing 9B/10B encoding technology, the 9B/10B encoding method of the present invention has the advantages of simple encoding process and fast encoding speed, is very easy to implement in hardware, and is suitable for application in high-speed communication systems.

The above-mentioned disclosures are only preferred embodiments of the present invention, and certainly cannot be used to limit the protection scope of the present invention. It can be understood that equivalent changes made according to the essence and scope defined in the appended claims of the present invention still belong to the scope covered by the present invention.

Claims (6)

1. a coding method of 9B/10B code, is characterized in that, comprises the following steps: S1: Divide the 9-bit codeword into three code segments, and perform mapping to obtain a negative polarity 10-bit codeword; S2: Calculate the unbalance degree of the negative polarity 10-bit codeword, and calculate the positive polarity 10-bit codeword according to the unbalance degree; S3: Calculate the polarity of the current channel code stream, and select the negative polarity 10-bit code word or the positive polarity 10-bit code word to output according to the current channel code stream polarity, so as to realize DC balance; Said step S1 comprises: S101: Divide the 9-bit codeword into three code segments with a length of 4bit, 1bit and 4bit and classify them respectively, so as to classify the 9-bit codeword; S102: Mapping the three code segments of the classified 9-bit codeword into three code segments with lengths of 4bit, 2bit and 4bit, respectively, to form the negative polarity 10bit codeword; The step S101 includes dividing the 4-bit information in the first code segment and the third code segment of the 9-bit codeword into 5 categories according to the number of "1"s in the bits, and the 1-bit information in the second code segment according to the number of bits The state of "1" and "0" in is divided into 2 categories, thereby dividing the 9bit codeword into 50 categories; The step S102 includes dividing the 4-bit information in the first code segment and the third code segment of the 10bit codeword into 5 categories according to the number of "1"s in the bits, and the 2-bit information in the second code segment according to the number of bits Combination states of "1" and "0" in are divided into 4 categories, so that the 10-bit codeword is divided into 100 categories. 2. The encoding method of 9B/10B code according to claim 1, characterized in that, said step S102 comprises using the classification of said 9bit codewords from the preset common codeword mapping rule revision table, common codeword mapping A corresponding mapping rule is selected from the rule table and the special codeword mapping rule table to map the 9-bit codeword. 3. The encoding method of 9B/10B code according to claim 2, characterized in that, said step S102 comprises if said 9bit code word is a common code word, query said common code word mapping rule revision table, if said The 9bit codeword can find the corresponding mapping rule in the normal codeword mapping rule modification table, then select the corresponding mapping rule to directly map according to the normal codeword mapping rule modification table and the special codeword mapping rule table, otherwise Mapping is performed according to corresponding mapping rules in the common codeword mapping rule table. 3. The encoding method of 9B/10B code according to claim 2, characterized in that, said step S102 comprises if said 9bit codeword is a special codeword, then according to the mapping in said special codeword mapping rule table rules for mapping. 4. the encoding method of 9B/10B code according to claim 1, is characterized in that, described step S2 comprises: If the degree of imbalance is zero, the positive 10bit codeword is the original code of the negative 10bit codeword; if the imbalance is not zero, the positive 10bit codeword is the original code of the negative 10bit codeword inverse code. 5. the encoding method of 9B/10B code according to claim 1, is characterized in that, described step S3 comprises: S301: Set the polarity of the channel code stream at the initial moment to be negative; S302: Determine the polarity of the current channel code stream, if the polarity is negative, then output the positive polarity 10bit code word at the next moment, and if the polarity is positive, then output the negative polarity 10bit codeword at the next moment Codeword; S303: Calculate the total unbalance degree of the channel code stream after outputting the 10-bit code word, and update the polarity of the channel code stream according to the total unbalance degree, and proceed to step S302 again. 6. the encoding method of 9B/10B code according to claim 5, is characterized in that, described step S303 comprises: If the total unbalance degree is positive, the polarity of the channel code stream is updated to be positive; If the total unbalance degree is negative, the polarity of the channel code stream is updated to be negative; If the total unbalance degree is zero, and the unbalance degree of the currently output 10bit codeword is zero, then the polarity of the channel code stream does not change; If the total unbalance degree is zero and the unbalance degree of the currently output 10-bit codeword is not zero, the polarity of the channel code stream is reversed.

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