循环码(7,4)

循环码的编码和译码

信息编码技术实验艮告三题目：循环码的编码和译码院系：计算机科学与工程学院班级：姓名：学号：【实验目的】1. 通过实验了解循环码的工作原理。

2. 了解生成多项式g(x)与编码、译码的关系。

3. 了解码距d 与纠、检错能力之间的关系。

【实验条件】仪器设备：PC 机，应用软件：Matlab 。

【实验内容］1、编程实现(7,4)系统循环码的编、译码。

已知(7, 4)循环码的生成多项式和校验多项式分别为：£(/)=疋+兀+ 1, h(x) = x 4+x 2+x + U 其生成矩阵和校验矩阵分别为：2、计算出所有的码字集合，可纠错误图样E (X 〉表和对应的错误伴随式表。

【程序代码】% (7,4)系统循环码编码.译码 clc;clear all;close all;n=7;k=4;r=n-k;mx=input ('请输入信息码字:m=\n' ) ; %输入信息码字 gx=[l Oil];x_nk=[l, zeros (1, r)];messg=conv(x.nk> mx); [qx, rxO] =deconv(messg, gx); %模 gx> qx 为所得除式，rxO 为余式 rx=mod (rxO, 2); %将余式rxO 转换为二进制cx=me ssg+rx;%编码码字多项式 c=cx瀚出编码码字 %=====绘图======== fs=1000;ts=l/fs;%fs 为一个单位内的样点 for i=l ：n%以方波形式输出编码码字，一个单位内一个码字for j=l ：fscx.wave ((i-1) *fs+j) =c (i);end endt=O ：ts ：n-ts;1 0 1 1000 0 10 1 1 00 G= 00101 1 0000 10 11 1110100 H = 0 1110 10 0011001%循环码生成多项式 %x* (n-k)> %x*(n-k)*mxplot (t, cx_wave); %以方波形式输出编码码字xlabel ('时间');ylabel C 幅度');title C (7,4)循环码编码输出波形')；axis([0 7 0 1. 2]);%==^ 码===============S=zeros (1, r); 颂始化校验子gx=[l Oil]; %循环码生成多项式Rx=input (*请输入接收码字:R=\n ) ;%接收码字多项式% Rx=[l 0 1 0 1 1 1];R=Rx；繊收码字[nx, SxO]=deconv(Rx, gx); %接收码字多项式除以gx, SxO为余式(十进制) Sx=mod(SxO, 2); %将SxO转换为G (2)域下多项式S=Sx(5:7); %SxO最后3位为检验子if S=[0 0 0] 燈验子二0disp('There is no wrong!'); % 显示接收码字无错E=[0 0 0 0 0 0 0]; %査表得出错误图样为0C=R; %译码输出为接收码字elseif S=[0 0 1] %接收码字第一位r0错dispC1 r0 is wrong!'); % 显示rO 错E=[0 0 0 0 0 0 1]; %査表得出错误图样C=xor (R, E); %译码输出C=R+Eelseif S=[0 1 0] %rl 错disp('rl is wrong!');E=[0 0 0 0 0 1 0];C=xor (R, E);elseif S=[l 0 0] 紐2 错disp('ir2 is wrong!');E=[0 0 0 0 1 0 0];C=xor(R, E);elseif S=[0 1 1] %r3 错dispC1 r3 is wrong!');E=[0 0 0 1 0 0 0];C=xor (R, E);elseif S=[l 1 0] %r4 错disp('r4 is wrong!');E=[0 0 1 0 0 0 0];C=xor (R, E);elseif S=[l 1 1] %r5 错dispC r5 is wrong!');E=[0 1 0 0 0 0 0];C=xor (R, E);elseif S=[l 0 1] %r6 错dispC* r6 is wrong!1);E=[l 0 0 0 0 0 0]; C=xor (R, E);endC %输出译码码字【实验结果】请输入信息码字:[10 110 10]10 110 1 0 1 1请输入接收码字:R 二 [10 11010 110] There is no wrong!C =10 11 0 1 0 1 1 0【实验心得】通过本次实验，我加深了对循环码的1:作原理的理解，也了解了生成多项式 g(x)与编码、译码的关系和码距d 与纠、检错的关系，在动手实验过程中，对知识点的印象更加清晰，让我的理解更加深刻了。

循环码(7,4)第3章循环码编码和译码3.1循环码概念循环码是线性分组码中一个重要的分支。

它的检、纠错能力较强，编码和译码设备并不复杂，而且性能较好，不仅能纠随机错误，也能纠突发错误。

循环码是目前研究得最成熟的一类码，并且有严密的代数理论基础，故有许多特殊的代数性质，这些性质有助于按所要求的纠错能力系统地构造这类码，且易于实现，所以循环码受到人们的高度重视，在fec系统中得到了广泛应用。

3.1.1、循环码定义定义。

一个线性分组码，若具有下列特性，则称为循环码。

设码字a。

（an。

1an。

2...（3-1）a1a0）若将码元左移一位，得a（1）。

（an。

2an。

1...a1a0an。

1）a（1）也是一个码字。

注意。

循环码并非由一个码字的全部循环移位构成。

3.1.2循环码的特点表3-1列出了某（7，4）循环码的全部码组码组编号a61234567800000000信息位a500001111a400110011a301010101a201110110监督位a100101100a001111001码组编号a691011121314151611111111信息位a500001111a400110011a301010101a210011001监督位a111000011（3-2）a001101001循环码有两个数学特征：1.线性分组码的封闭型。

即如果c1，c2，是与消息m1，m2对应的码字，则c1+c2必定是与m1+m2对应的码字。

2.循环性，即任一许用码组经过循环移位后所得到的码组仍为该许用码组集合中的一个码组。

即若（an-1an-2…a1a0）为一循环码组，则（an-2an-3…anan-1）、（an-3an-2…an-1an-2）、……还是许用码组。

也就是说，不论是左移还是右移，也不论移多少位，仍然是许用的循环码组。

以3号码组（0010111）为例，左移循环一位变成6号码组（0101110），依次左移一位构成的状态图如图1.1-2所示。

matlab(7,4)汉明码和(7,4)循环码的编程设计

二、创新实验设计创新实验一：（7,4）汉明码的编码与译码实现1、实验目的实现（7,4）汉明码的编码与译码，通过这次实验不但加深了对汉明码编码和译码原理了解，而且对线性分组码有所了解。

2、实验原理线性分组码的构造方法比较简单、理论较为成熟，应用比较广泛。

汉明码是一种能够纠正一个错码的效率比较高的线性分组码，下面以（7,4）码为例就汉明码的编码与译码分别进行介绍：（1）编码原理一般来说，若汉明码长为n ，信息位数为k ，则监督位数r=n-k 。

若希望用r 个监督位构造出r 个监督关系式来指示一位错码的n 种可能位置，则要求21r n -≥或211rk r -≥++ (1)设汉明码（n,k ）中k=4，为了纠正一位错码，由式（1）可知，要求监督位数r ≥3。

若取r=3,则n=k+r=7。

这样就构成了（7,4）码。

用6543210a a a a a a a 来表示这7个码元，用123s s s 的值表示3个监督关系式中的校正子，则123s s s 的值与错误码元位置的对应关系可以规定如表1所列。

表2.1 校正子和错码位置的关系则由表1可得监督关系式：16542s a a a a =⊕⊕⊕()226531s a a a a =⊕⊕⊕()3 36430s a a a a =⊕⊕⊕()4 在发送端编码时，信息位6543a a a a 的值决定于输入信号，因此它们是随机的。

监督位2a 、1a 、a 应根据信息位的取值按监督关系来确定，为使所编的码中无错码，则123,,S S S 等于0，即65426531643000(5)0a a a a a a a a a a a a ⊕⊕⊕=⎧⎪⊕⊕⊕=⎨⎪⊕⊕⊕=⎩方程组（5）可等效成如下矩阵形式6543210111010001101010010110010a a a a a a a ⎡⎤⎢⎥⎢⎥⎢⎥⎡⎤⎡⎤⎢⎥⎢⎥⎢⎥=⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎣⎦⎣⎦⎢⎥⎢⎥⎢⎥⎣⎦（6）式(6)可简化为0T T HA =，H 为监督矩阵，则由式(6)可得到监督矩阵11101001101010=[P I ] (7)1011001r H ⎡⎤⎢⎥=⎢⎥⎢⎥⎣⎦因为生成矩阵'=[I Q]=[I ]k k G P ，所以由(7)得生成矩阵G 如下：[]k 10001110100110[']00101010001011k G I Q I P ⎡⎤⎢⎥⎢⎥===⎢⎥⎢⎥⎣⎦然后利用信息位和生成矩阵G 相乘产生整个码组，即有[][]65432106543=(8)A a a a a a a a a a a a G=其中A 为整个码组矩阵，6543a a a a 是信息位。

基于51单片机的(7,4)循环码编程

基于51单片机的（7，4）循环码编译码的设计电子信息科学与技术专业学生王东菊指导老师王心水摘要: 通信系统中最重要的是通信质量问题，而衡量通信系统质量的主要性能指标就是有效性和可靠性。

所谓有效性是指要求系统高效率地传输信息，在数字通信系统中信源编码旨在解决有效问题；所谓可靠性，是指要求系统可靠地传输消息，而信道编码旨在解决可靠性问题。

以往循环码编译电路大多用移位寄存器和模2构成的线性时序网络来完成。

基本电路简单，容易实现。

但在体积和功能扩展上受到了限制而不能发挥更大的作用。

采用（7，4）循环码，充分运用单片机的软件功能进行编码及译码纠错,可有效的克服来自通讯信道的干扰,保证数据通讯的可靠及系统的稳定,使误码率大幅度的降低。

而且，只要改变软件算法，即可适用于不同微机、不同字长的需要。

总之，本设计使用软件编程方法实现编译码过程既有简化电路、可靠性高、运算速度快、体积小等优点，又可以扩展电路其他功能，而且可以根据需要任意修改，这是其它硬件电路所无法相比的，是抛开传统模式的一种新尝试。

关键词: 单片机通信循环码编码译码纠错抗干扰The design of Encoding and Decoding of (7,4) Cyclic CodeBased on the 51 SCMStudent majoring in Electronic information science and technology Wang DongjuTutor Wang XinshuiAbstract:The most important problem in communication system is communication quality, and the most important measures of the quality of communication system is effectiveness and reliability. So-called effectiveness refers to the system efficiently transmit information in digital communication system .So-called reliability, refers to the system, and reliable transmission channel encoding aims at solving problems. Reliability, Previous cycle code compiler circuit with the shift register and mostly composed of two linear temporal network to accomplish. The basic circuit is simple and easy to implement. But in volume and function expansion by restrictions and cannot play a bigger role. Using (7,4) codes, make full use of the MCU software functions encoded and decoding correction, which can effectively overcome the interference from communication channel, ensure the reliability of data communication systems, the stability and the ber greatly reduced. And, just change the software algorithm, and can be used in different microcomputer, different words long need. Anyhow, this design using the software programming method (both simplified decoding process, high reliability, operation circuit faster, smaller, and may expand advantages and other functions, circuit according to need any modification, this is compared to other hardware circuit cannot abandon traditional pattern, is a new attempt.Key words: Microcontroller;Communication;Cyclic code;Encode;Decode;Correcting code;Anti-intreferance引言在数据通信中，误码率是项重要指标。

基于FPGA的(7,4)循环码编码和译码的实现

基于FPGA的(7,4)循环码编码和译码的实现摘要：循环码在实际通信中被广泛使用，因为它可以提高信息传输的可靠性和有效性。

随着FPGA芯片的普及，其在各个领域的已广泛使用。

本文在简单的理论分析上，描述了在FPGA中实现(7,4)循环码的编码与译码的实现方案。

关键词：(7,4)循环码FPGA 编码译码1.引言现场可编程逻辑门阵列（FPGA），是一个含有可编辑元件的半导体设备，可供使用者现场程式化的逻辑门阵列元件。

目前以硬件描述语言（Verilog 或VHDL）所完成的电路设计，可以经过简单的综合与布局，快速的烧录至FPGA 上进行测试，是现代IC 设计验证的技术主流。

为了使信号具有较好的抗干扰能力，就要对信号加以改造，使信号内部结构具有更强的规律性和相互关联性，以致在噪声破坏了信号的结构时，仍能根据信号原有的内在规律性和相互关联性来发现错误，甚至改正错误，恢复原有的信息。

其一般方法是：按照某种规律，对原来的码组添加一些新的码元——监督码元，而原码组中的码元则称为信息码元。

监督码元的作用是监督该码组在传输过程中是否发生了错误，甚至指出是哪位或哪些码元发生了错误，以便纠正，添加监督码元的方法（规律或规则）不同，就形成不同的编码方法。

2.(7,4)循环码在通信系统中，为提高信息传输可靠性,广泛使用了具有一定纠错能力的信道编码技术,某(7,4)循环码的生产多项式是：，则其生成矩阵是，具体结果见表其中：，，，并根据生成矩阵与监督矩阵的关系G·H=0从而得到：（2）根据公式（2）可得到：（3）3.编码与译码“公式（3）”表达了根据信息码元值得到各个监督码元值的运算公式，根据这些公式，我们可以得到信息元值与监督元值的具体关系。

在FPGA中进行(7,4)循环码的编码时，可以根据“公式(3)”编写算法由信息码元值来计算监督码元值，也可以采用查表法由信息码元来计算监督码元。

后面一种方法不适用于信息码元位数及监督码元位数较多的循环码，因为这时列出情况较多，其编程较前种方法较复杂。

循环码(7,4)

8.4 循环码时间：2012年09月01日信息来源：《通信原理》精品课程网站点击：2452次我要评论(0) 【字体：大中小】循环码是线性分组码重要的一个子类，现有的重要线性分组码都是循环码或与循环码密切相关。

与其他大多数码相比，循环码的编码及译码易于用简单的具有反馈连接的移位寄存器来实现，这是它的优势所在。

另外，对它的研究是建立在比较严密的数学方法基础之上，因此比较容易获得有效的译码方案。

循环码在实际中应用很广。

8.4.1 循环码基本概念一个线性（）分组码，如果它的任一码字经过循环移位后（左移或右移），仍然是该码的一个码字，则称该码为循环码。

上一节中表8-3所示的（7，3）分组码就是一个循环码。

为了便于观察，将（7，3）码重新排列如表8-9所示。

表8-9 循环码的循环移位在代数编码理论中，常用多项式（8.4-1）来描述一个码字。

表8-9中的任一码组可以表示为（8.4-2）这种多项式中，仅是码元位置的标记，因此我们并不关心x的取值，这种多项式称为码多项式。

例如，码字（0100111）可以表示为（8.4-3）左移一位后为（1001110），其码字多项式为（8.4-4）需要注意的是，码字多项式和一般实数域或复数域的多项式有所不同，码字多项式的运算是基于模二运算的。

（1）码多项式相加，是同幂次的系数模二加，不难理解，两个相同的多项式相加，结果系数全为0。

例如（8.4-5）（2）码多项式相乘，对相乘结果多项式作模二加运算。

例如（8.4-6）（3）码多项式相除，除法过程中多项式相减按模二加方法进行。

当被除式的幂次高于等于除式的幂次，就可以表示为一个商式和一个分式之和，即（8.4-7）其中余式的幂次低于的幂次。

把称作对取模的运算结果，并表示为（8.4-8）有了这个运算规则，就可以很方便地表示一个移位后码字多项式。

可以证明，字长为的码字多项式和经过次左移位后的码字多项式的关系为（8.4-9）例如，（7，3）循环码的码字（1001110），其多项式为，移位3次后的多项式可求得如下：（8.4-10）即，它对应的码字为11101008.4.2 循环码生成多项式由表8-9可知，（7，3）循环码的非0码字多项式是由一个多项式分别乘以得到的。

实验2 信道编码----(7,4)循环码

信息论与编码实验报告姓名：学号：院系：班级：指导教师：实验2 信道编码----（7,4）循环码一、实验目的1.掌握循环码的编码原理（生成多项式、校验多项式等）2.掌握VB开发环境的使用（尤其是程序调试技巧）3.掌握VB的编程技巧二、实验环境1.计算机2.Windows 2000 或以上3.VB三、实验内容根据信道编码——循环码的编码原理，制作（7,4）循环码的码字生成器软件。

要求软件有简单的用户界面，当输入信息码字时，软件能够输出相应的循环码字。

实验结果要求：1、g(x)= x3+ x2+1；2、当输入m(x)= x3+x2时电路工作过程中各寄存器的状态。

四、实验原理1、实验原理循环码定义：设CH是一个[n.k]线性分组码，C1是其中的一个码字，若C1的左(右)循环移位得到的n 维向量也是CH中的一个码字，则称CH是循环码。

循环码的生成多项式和生成矩阵：全0码字除外）称为生成多项式，用g(x)表示。

可以证明生成多项式g(x)具有以下特性：（1）g(x)是一个常数项为1的r=n-k次多项式；（2）g(x)是的一个因式；（3）该循环码中其它码多项式都是g(x)的倍式。

为了保证构成的生成矩阵G的各行线性不相关，通常用g(x)来构造生成矩阵，这时，生成矩阵G(x)可以表示成为其中，因此，一旦生成多项式g(x)确定以后，该循环码的生成矩阵就可以确定，进而该循环码的所有码字就可以确定。

显然，上式不符合形式，所以此生成矩阵不是典型形式，不过，可以通过简单的代数变换将它变成典型矩阵。

2、实验方法循环码的编码方法在编码时，首先需要根据给定循环码的参数确定生成多项式g(x)，也就是从的因子中选一个（n-k）次多项式作为g(x)；然后，利用循环码的编码特点，即所有循环码多项式A(x)都可以被g(x)整除，来定义生成多项式g(x)。

根据上述原理可以得到一个较简单的系统循环码编码方法：设要产生（n,k）循环码，m(x)表示信息多项式，则其次数必小于k，而·m(x)的次数必小于n，用·m(x)除以g(x)，可得余数r(x)，r(x)的次数必小于（n-k），将r(x)加到信息位后作监督位，就得到了系统循环码。

信息论(7,4)汉明码(7,3)循环码

functionvarargout = Hamming(varargin)% HAMMING M-file for Hamming.fig% HAMMING, by itself, creates a new HAMMING or raises the existing % singleton*.%% H = HAMMING returns the handle to a new HAMMING or the handle to % the existing singleton*.%% HAMMING('CALLBACK',hObject,eventData,handles,...) calls thelocal% function named CALLBACK in HAMMING.M with the given input arguments. %% HAMMING('Property','Value',...) creates a new HAMMING or raises the % existing singleton*. Starting from the left, property value pairs are% applied to the GUI before Hamming_OpeningFunction gets called. An % unrecognized property name or invalid value makes property application% stop. All inputs are passed to Hamming_OpeningFcn via varargin. %% *See GUI Options on GUIDE's Tools menu. Choose "GUI allows only one% instance to run (singleton)".%% See also: GUIDE, GUIDATA, GUIHANDLES% Edit the above text to modify the response to help Hamming% Last Modified by GUIDE v2.5 07-Jan-2008 20:22:48% Begin initialization code - DO NOT EDITgui_Singleton = 1;gui_State = struct('gui_Name', mfilename, ...'gui_Singleton', gui_Singleton, ...'gui_OpeningFcn', @Hamming_OpeningFcn, ...'gui_OutputFcn', @Hamming_OutputFcn, ...'gui_LayoutFcn', [] , ...'gui_Callback', []);ifnargin&&ischar(varargin{1})gui_State.gui_Callback = str2func(varargin{1});endifnargout[varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});elsegui_mainfcn(gui_State, varargin{:});end% End initialization code - DO NOT EDIT% --- Executes just before Hamming is made visible.functionHamming_OpeningFcn(hObject, eventdata, handles, varargin)% This function has no output args, see OutputFcn.% hObject handle to figure% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% varargin command line arguments to Hamming (see VARARGIN)% Choose default command line output for Hamminghandles.output = hObject;% Update handles structureguidata(hObject, handles);% UIWAIT makes Hamming wait for user response (see UIRESUME)% uiwait(handles.figure1);% --- Outputs from this function are returned to the command line. functionvarargout = Hamming_OutputFcn(hObject, eventdata, handles)% varargout cell array for returning output args (see VARARGOUT);% hObject handle to figure% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Get default command line output from handles structurevarargout{1} = handles.output;function edit1_Callback(hObject, eventdata, handles)% hObject handle to edit1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit1 as text% str2double(get(hObject,'String')) returns contents of edit1 as a double% --- Executes during object creation, after setting all properties. function edit1_CreateFcn(hObject, eventdata, handles)% hObject handle to edit1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit2_Callback(hObject, eventdata, handles)% hObject handle to edit2 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit2 as text% str2double(get(hObject,'String')) returns contents of edit2 as a double% --- Executes during object creation, after setting all properties. function edit2_CreateFcn(hObject, eventdata, handles)% hObject handle to edit2 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit3_Callback(hObject, eventdata, handles)% hObject handle to edit3 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit3 as text% str2double(get(hObject,'String')) returns contents of edit3 as a double% --- Executes during object creation, after setting all properties. function edit3_CreateFcn(hObject, eventdata, handles)% hObject handle to edit3 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit4_Callback(hObject, eventdata, handles)% hObject handle to edit4 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit4 as text% str2double(get(hObject,'String')) returns contents of edit4 as a double% --- Executes during object creation, after setting all properties. function edit4_CreateFcn(hObject, eventdata, handles)% hObject handle to edit4 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit5_Callback(hObject, eventdata, handles)% hObject handle to edit5 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit5 as text% str2double(get(hObject,'String')) returns contents of edit5 as a double% --- Executes during object creation, after setting all properties. function edit5_CreateFcn(hObject, eventdata, handles)% hObject handle to edit5 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit6_Callback(hObject, eventdata, handles)% hObject handle to edit6 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit6 as text% str2double(get(hObject,'String')) returns contents of edit6 as a double% --- Executes during object creation, after setting all properties. function edit6_CreateFcn(hObject, eventdata, handles)% hObject handle to edit6 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');end% --- Executes on button press in pushbutton1.function pushbutton1_Callback(hObject, eventdata, handles)% hObject handle to pushbutton1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)chose=get(handles.popupmenu1,'value');if chose==1;clc;msg=str2num(get(handles.edit1,'string'))%信息产生code=encode(msg,7,4);%汉明编码rcv=decode(code,7,4);%汉明译码set(handles.edit2,'string',num2str(code));set(handles.edit3,'string',num2str(rcv));elsek=str2num(get(handles.edit1,'string'));code1=encode(k,7,3,'cyclic/binary');rcv1=decode(code1,7,3,'cyclic/binary');set(handles.edit2,'string',num2str(code1));set(handles.edit3,'string',num2str(rcv1));endfunction edit7_Callback(hObject, eventdata, handles)% hObject handle to edit7 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit7 as text% str2double(get(hObject,'String')) returns contents of edit7 as a double% --- Executes during object creation, after setting all properties. function edit7_CreateFcn(hObject, eventdata, handles)% hObject handle to edit7 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit8_Callback(hObject, eventdata, handles)% hObject handle to edit8 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit8 as text% str2double(get(hObject,'String')) returns contents of edit8 as a double% --- Executes during object creation, after setting all properties. function edit8_CreateFcn(hObject, eventdata, handles)% hObject handle to edit8 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit9_Callback(hObject, eventdata, handles)% hObject handle to edit9 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit9 as text% str2double(get(hObject,'String')) returns contents of edit9 asa double% --- Executes during object creation, after setting all properties. function edit9_CreateFcn(hObject, eventdata, handles)% hObject handle to edit9 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit10_Callback(hObject, eventdata, handles)% hObject handle to edit10 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit10 as text% str2double(get(hObject,'String')) returns contents of edit10 as a double% --- Executes during object creation, after setting all properties. function edit10_CreateFcn(hObject, eventdata, handles)% hObject handle to edit10 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit15_Callback(hObject, eventdata, handles)% hObject handle to edit15 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit15 as text% str2double(get(hObject,'String')) returns contents of edit15 as a double% --- Executes during object creation, after setting all properties. function edit15_CreateFcn(hObject, eventdata, handles)% hObject handle to edit15 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');end% --- Executes on button press in pushbutton2.function pushbutton2_Callback(hObject, eventdata, handles)% hObject handle to pushbutton2 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)chose=get(handles.popupmenu1,'value');if chose==1;[H,G,N,K]=hammgen(3); %产生H和G矩阵for i=1:2^Kfor j=K:-1:1if rem(i-1,2^(-j+K+1))>=2^(-j+K)U(i,j)=1;elseU(i,j)=0;endendendC=rem(U*G,2);A=str2num(get(handles.edit7,'string'));[r,l]=size(A);E=[0 0 0 0 0 0 0;0 0 0 0 0 0 1;0 0 0 0 0 1 0;0 0 0 0 1 0 0;0 0 0 1 0 00;0 0 1 0 0 0 0;0 1 0 0 0 0 0;1 0 0 0 0 0 0]; %%%%%求校正子，然后将其转化成十进制数S=rem(A*H',2);Sx=bi2de(S,'left-msb');%%%%下面是（7,4）码检错for i=1:rswitch(Sx)case 0disp=('此接收码字没错')case 1disp=('注意：此接收码字的第3位有错，请纠正')case 2disp=('注意：此接收码字的第2位有错，请纠正')case 4disp=('注意：此接收码字的第1位有错，请纠正')case 3disp=('注意：此接收码字的第5位有错，请纠正')case 5disp=('注意：此接收码字的第7位有错，请纠正')case 6disp=('注意：此接收码字的第4位有错，请纠正')case 7disp=('注意：此接收码字的第6位有错，请纠正')endendset(handles.edit8,'string',disp);%%%下面为在知道哪位出错的情况下，进行纠正for i=1:rswitch(Sx)case 0B(i,:)=A(i,:)+E(1,:);case 1B(i,:)=A(i,:)+E(6,:);case 2B(i,:)=A(i,:)+E(7,:);case 4B(i,:)=A(i,:)+E(8,:);case 3B(i,:)=A(i,:)+E(4,:);case 5B(i,:)=A(i,:)+E(2,:);case 6B(i,:)=A(i,:)+E(5,:);case 7B(i,:)=A(i,:)+E(3,:);endendB=rem(B,2);set(handles.edit9,'string',num2str(B));elsegenpoly=cyclpoly(7,3);[p,g]=cyclgen(7,genpoly);c=str2num(get(handles.edit7,'string'));s=rem(p*c',2);Sx=s(1,1)+s(2,1)*2+s(3,1)*4+s(4,1)*8;switch(Sx)case 0set(handles.edit8,'string','此接收碼无错');set(handles.edit9,'string',num2str(c));case 1if c(1,1)==0c(1,1)=1;elsec(1,1)=0endset(handles.edit8,'string','注意：此接收码字的第一位有错，请纠正');set(handles.edit9,'string',num2str(c));case 2if c(1,2)==0c(1,2)=1;elsec(1,2)=0endset(handles.edit9,'string',num2str(c));set(handles.edit8,'string','注意：此接收码字的第二位有错，请纠正');case 4if c(1,3)==0c(1,3)=1;elsec(1,3)=0endset(handles.edit9,'string',num2str(c));set(handles.edit8,'string','注意：此接收码字的第三位有错，请纠正');case 8if c(1,4)==0c(1,4)=1;elsec(1,4)=0endset(handles.edit9,'string',num2str(c));set(handles.edit8,'string','注意：此接收码字的第四位有错，请纠正');case 13if c(1,5)==0c(1,5)=1;elsec(1,5)=0endset(handles.edit9,'string',num2str(c));set(handles.edit8,'string','注意：此接收码字的第五位有错，请纠正');case 7if c(1,6)==0c(1,6)=1;elsec(1,6)=0endset(handles.edit9,'string',num2str(c));set(handles.edit8,'string','注意：此接收码字的第六位有错，请纠正');case 14if c(1,7)==0c(1,7)=1;elsec(1,7)=0endset(handles.edit9,'string',num2str(c));set(handles.edit8,'string','注意：此接收码字的第七位有错，请纠正');case{3,5,6,9,10,11,12,15}set(handles.edit8,'string','注意：此接收码字有错');set(handles.edit9,'string','注意：无法纠正无法判别错在哪位'); endend% --- Executes on selection change in popupmenu1.function popupmenu1_Callback(hObject, eventdata, handles)% hObject handle to popupmenu1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: contents = get(hObject,'String') returns popupmenu1 contents as cell array% contents{get(hObject,'Value')} returns selected item from popupmenu1% --- Executes during object creation, after setting all properties. function popupmenu1_CreateFcn(hObject, eventdata, handles)% hObject handle to popupmenu1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: popupmenu controls usually have a white background on Windows. % See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');end。

matlab(74)汉明码和(74)循环码的编程设计

二、创新实验设计创新实验一：（7,4）汉明码的编码与译码实现1、实验目的实现（7,4）汉明码的编码与译码，通过这次实验不但加深了对汉明码编码和译码原理了解，而且对线性分组码有所了解。

2、实验原理线性分组码的构造方法比较简单、理论较为成熟，应用比较广泛。

汉明码是一种能够纠正一个错码的效率比较高的线性分组码，下面以（7,4）码为例就汉明码的编码与译码分别进行介绍：（1）编码原理一般来说，若汉明码长为n ，信息位数为k ，则监督位数r=n-k 。

若希望用r 个监督位构造出r 个监督关系式来指示一位错码的n 种可能位置，则要求21r n -≥或211rk r -≥++ (1)设汉明码（n,k ）中k=4，为了纠正一位错码，由式（1）可知，要求监督位数r ≥3。

若取r=3,则n=k+r=7。

这样就构成了（7,4）码。

用6543210a a a a a a a 来表示这7个码元，用123s s s 的值表示3个监督关系式中的校正子，则123s s s 的值与错误码元位置的对应关系可以规定如表1所列。

表2.1 校正子和错码位置的关系则由表1可得监督关系式：16542s a a a a =⊕⊕⊕()226531s a a a a =⊕⊕⊕()3 36430s a a a a =⊕⊕⊕()4 在发送端编码时，信息位6543a a a a 的值决定于输入信号，因此它们是随机的。

监督位2a 、1a 、0a 应根据信息位的取值按监督关系来确定，为使所编的码中无错码，则123,,S S S 等于0，即65426531643000(5)0a a a a a a a a a a a a ⊕⊕⊕=⎧⎪⊕⊕⊕=⎨⎪⊕⊕⊕=⎩方程组（5）可等效成如下矩阵形式6543210111010001101010010110010a a a a a a a ⎡⎤⎢⎥⎢⎥⎢⎥⎡⎤⎡⎤⎢⎥⎢⎥⎢⎥=⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎣⎦⎣⎦⎢⎥⎢⎥⎢⎥⎣⎦（6）式(6)可简化为0T T HA =，H 为监督矩阵，则由式(6)可得到监督矩阵11101001101010=[P I ] (7)1011001r H ⎡⎤⎢⎥=⎢⎥⎢⎥⎣⎦因为生成矩阵'=[I Q]=[I ]k k G P ，所以由(7)得生成矩阵G 如下：[]k 10001110100110[']00101010001011k G I Q I P ⎡⎤⎢⎥⎢⎥===⎢⎥⎢⎥⎣⎦然后利用信息位和生成矩阵G 相乘产生整个码组，即有[][]65432106543=(8)A a a a a a a a a a a a G=其中A 为整个码组矩阵，6543a a a a 是信息位。

(完整word版)matlab(7,4)汉明码和(7,4)循环码的编程设计

二、创新实验设计创新实验一：（7,4）汉明码的编码与译码实现1、实验目的实现（7,4）汉明码的编码与译码，通过这次实验不但加深了对汉明码编码和译码原理了解，而且对线性分组码有所了解。

2、实验原理线性分组码的构造方法比较简单、理论较为成熟，应用比较广泛。

汉明码是一种能够纠正一个错码的效率比较高的线性分组码，下面以（7,4）码为例就汉明码的编码与译码分别进行介绍：（1）编码原理一般来说，若汉明码长为n ，信息位数为k ，则监督位数r=n-k 。

若希望用r 个监督位构造出r 个监督关系式来指示一位错码的n 种可能位置，则要求21r n -≥或211rk r -≥++ (1)设汉明码（n,k ）中k=4，为了纠正一位错码，由式（1）可知，要求监督位数r ≥3。

若取r=3,则n=k+r=7。

这样就构成了（7,4）码。

用6543210a a a a a a a 来表示这7个码元，用123s s s 的值表示3个监督关系式中的校正子，则123s s s 的值与错误码元位置的对应关系可以规定如表1所列。

表2.1 校正子和错码位置的关系则由表1可得监督关系式：16542s a a a a =⊕⊕⊕()226531s a a a a =⊕⊕⊕()3 36430s a a a a =⊕⊕⊕()4 在发送端编码时，信息位6543a a a a 的值决定于输入信号，因此它们是随机的。

监督位2a 、1a 、a 应根据信息位的取值按监督关系来确定，为使所编的码中无错码，则123,,S S S 等于0，即65426531643000(5)0a a a a a a a a a a a a ⊕⊕⊕=⎧⎪⊕⊕⊕=⎨⎪⊕⊕⊕=⎩方程组（5）可等效成如下矩阵形式6543210111010001101010010110010a a a a a a a ⎡⎤⎢⎥⎢⎥⎢⎥⎡⎤⎡⎤⎢⎥⎢⎥⎢⎥=⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎣⎦⎣⎦⎢⎥⎢⎥⎢⎥⎣⎦（6）式(6)可简化为0T T HA =，H 为监督矩阵，则由式(6)可得到监督矩阵11101001101010=[P I ] (7)1011001r H ⎡⎤⎢⎥=⎢⎥⎢⎥⎣⎦因为生成矩阵'=[I Q]=[I ]k k G P ，所以由(7)得生成矩阵G 如下：[]k 10001110100110[']00101010001011k G I Q I P ⎡⎤⎢⎥⎢⎥===⎢⎥⎢⎥⎣⎦然后利用信息位和生成矩阵G 相乘产生整个码组，即有[][]65432106543=(8)A a a a a a a a a a a a G=其中A 为整个码组矩阵，6543a a a a 是信息位。

循环码

谢谢观看
常用CRC码
CRC码生成多项式 CRC－12 x12+x11+x3+x2+x+1 CRC－16 x16+x15+x2+1 CRC－CCITT x16+x12+x5+1 BCH码 BCH码是循环码的一个重要的子类，它是一种能纠正多个随机错误的应用最为广泛和有效的差错控制码。定义：对于任意正整数m(m≥3)和t(t<2m－1=一定存在一个具有下列参数的二进制BCH码：
编码种类
十六进制数自然二进制码循环二进制码十六进制数自然二进制码循环二进制码 0 0000 0000 8 1000
特征
为了探讨循环码的特征，把码字C=(Cn－1 Cn－2…C1C0)用如下的码多项式C(x)来表示。（1）特性一在一个(n,k)循环码中，存在惟一的一个n－k次码多项式：每一个码多项式C(x)都是g(x)的一个倍式，反之每个为g(x)倍式，且次数小于等于n－1的多项式必是一个码多项式。由此可见，(n,k)循环码中的每一个码多项式C(x)均可由下式表示：如果m(x)的系数(mk－1…m1m0)就是表示待编码的k位信息位，则C(x)就是对应于此信息组m(x)的码多项式。因此(n,k)循环码完全可由g(x)确定。g(x)也称为循环码(n,k)的生成多项式。g(x)的次数n－k等于码中一致校验位的位数。
译码器
缩短循环码
循环码的生成多项式g(x)应该是xn+1的一个(n－k)次因子，但有时在给定码长n时，xn+1的因子不能满足设计者的需要，为了增加选择机会，往往采用缩短循环码。
在(n,k)循环码的2k个码字中选择前i位信息位为0的码字，共有2k－i个，组成一个新的码字集。这样就构成了一个(n－i,k－i)缩短循环码。

二进制(7,4)循环码编码器与译码器的仿真

二进制(7,4)循环码编码器与译码器的仿真摘要：1.全文概述2.二进制(7,4)循环码编码器原理3.二进制(7,4)循环码译码器原理4.仿真实验及结果分析5.总结正文：【提纲1】1.全文概述本文主要介绍了二进制(7,4)循环码编码器与译码器的仿真设计。

通过编码器将7位二进制信息编码为4位二进制码，再通过译码器将4位二进制码还原为7位二进制信息。

文中详细阐述了编码器与译码器的原理，并进行了仿真实验及结果分析。

【提纲2】2.二进制(7,4)循环码编码器原理二进制(7,4)循环码编码器是一种将7位二进制信息编码为4位二进制码的编码器。

其原理如下：- 首先，将7位二进制信息进行分组，每组包含4位二进制数；- 然后，对每组4位二进制数进行异或操作，得到对应的4位二进制码；- 最后，将得到的4位二进制码进行循环移位，得到最终的编码结果。

【提纲3】3.二进制(7,4)循环码译码器原理二进制(7,4)循环码译码器的原理与编码器相反。

首先，将4位二进制码进行循环移位，得到原始的4位二进制数。

然后，对每个4位二进制数进行解码，得到对应的7位二进制信息。

解码过程主要包括：- 将4位二进制码转换为12位二进制码；- 对12位二进制码进行分组，每组包含7位二进制数；- 对每组7位二进制数进行译码，得到原始的7位二进制信息。

【提纲4】4.仿真实验及结果分析为了验证二进制(7,4)循环码编码器与译码器的正确性，本文进行了仿真实验。

实验结果表明，编码器能够将7位二进制信息正确编码为4位二进制码，译码器能够将4位二进制码还原为7位二进制信息。

通过对比编码前后的信息，证明了编码器与译码器的有效性。

【提纲5】5.总结本文对二进制(7,4)循环码编码器与译码器进行了详细阐述，并进行了仿真实验。

结果表明，该编码器与译码器能够实现二进制信息的编码与解码。

74循环码——精选推荐

循环码的系统编码1.循环码：一个线性分组码，若具有下列特性，称为循环码。

设码字c ＝（cn-1，cn-2，…，c1，c0）若将码元左移一位，得c (1)＝（cn-2，…，c1，c0，cn-1）c (1)也是一个码字。

2.码多项式：设c ＝（cn-1 cn-2 … c1 c0）是（n ，k ）循环码的一个码字，则与其对应的多项式 c (x)＝c n 1-c x c x c x n n n 01221.........+++--- 称为码字c 的码字多项式（或码多项式）。

3.非系统循环马变系统码的方法：（1）首先将信息元多项式m(x)乘以x k n )(-成为x k n )(-m(x)；（2）将xn-km(x)除以生成多项式g(x)得到余式r(x)，该余式就是校验元多项式，（3）系统码的码字多项式c(x)＝xn-km(x)＋r(x)。

用电路实现编码时可采用以g(x)为除式的除法电路，该电路是一个（n-k ）级移位寄存器。

以生成多项式g(x)＝x3＋x2＋1的（7，4）循环码的编码电路如下：电路的工作原理：输入消息前需将寄存器清零处理，闭合k1，再输入消息序列，序列的输入是从后位逐个输入，一边直接输出到输出码字中（右后向前逐个输入的），一边影响寄存器里的存储信息；当输完消息序列后断开K1，闭合K2，将移位寄存器的信息序列逐个输出到接收的码字中。

程序总代码：#include <iostream.h>#include<windows.h>void main(){int g[4]={1,1,0,1};int b[3],u[4],v[7];int i,j,m,n;cout<<"移位寄存器的初始值为："<<" ";for(i=0;i<3;i++){ //初始时刻，将寄存器清零b[i]=0;cout << b[i];}cout << endl;Sleep(1000);//调用的库函数windows中的延时函数，延时1秒。

7,4循环码的误比特率

7,4循环码的误比特率The bit error rate (BER) of a 7,4 cyclic code is an important metric for evaluating the performance of the code in noisy communication channels. A 7,4 cyclic code is a type of linear block code that possesses certain cyclic properties, making it suitable for use in various error-correction and detection schemes.7,4循环码的误比特率（BER）是评估该码在有噪声通信信道中性能的重要指标。

7,4循环码是一种具有特定循环性质的线性分组码，适用于各种纠错和检测方案。

The BER measures the probability of a bit being decoded incorrectly at the receiver due to noise or other disturbances in the channel. For a 7,4 cyclic code, the BER depends on several factors, including the code's design, the channel conditions, and the decoding algorithm used.误比特率衡量的是由于信道中的噪声或其他干扰导致接收器解码错误的概率。

对于7,4循环码，误比特率取决于多个因素，包括码的设计、信道条件以及所使用的解码算法。

The design of a 7,4 cyclic code involves selecting a set of codewords that satisfy certain constraints, such as having a specific minimum distance between codewords. This minimum distance determines the code's ability to detect and correct errors. A larger minimum distance typically results in a lower BER.7,4循环码的设计涉及选择一组满足特定约束的码字，如具有特定最小码距。

(7,4)循环码的编码和译码(精品WORD文档)

(7,4)循环码的编码译码编码的实验原理：根据循环码的代数性质建立系统编码的过程，可以把消息矢量用如下多项式表示：m(x) = m k」x k' + m k/X k，十…十m i x 十m°要编码成系统循环码形式，把消息比特移入码字寄存器的最右边k 位，而把监督比特加在最左边的n-k个中，则要用x n」乘以m(x)得到n _kx m(x)= mk」x n_l m k-2x n-2…m1x nJ^ 1m0x nJ<nx m(x)= q(x) g(x)+ p(x)，其中p(x)可以表示为n _k _1 Er n -kp(x)= P n 上」X …Pi X P o ，贝y p(x)+ x m(x)nd 丄n _2 丄丄n _k H i 丄n _k n _k A= m k」x m k/x …mi x m o x + p n」_i x …pi x p o另U(x)= p(x)+ x m(x)，贝卩U=( p o , p i , p2，•…，P n_k」，m o , m i，•…, m k 1 ) o本实验根据以上原理，用matlab实现书上例6.8系统形式的循环3码，生成多项式为g(x)= x x(7,4)循环码的编码的程序如下：clear;clc;a=[1 0 1 1];%高次项系数在前的生成多项式Gx=[1 0 1 1];%将数组a的高位依次放在数组Data的低位Data二zeros(1,7);Data(1)=a(4);Data(2)=a(3);Data(3)=a(2);Data(4)=a(1);%Data除以Gx得到余数Rx[Qx,Rx]=deconv(Data,Gx); b=Rx+Data; %将数组b 的高位放在后面c=b(1);b(1)=b(7);b(7)=c;c=b(2);b(2)=b(6);b(6)=c;c=b(3);b(3)=b(5);b(5)=c;%将数组b 校正for i=1:7if rem(abs(b(i)),2)==0b(i)=0;endendfor i=1:7if rem(abs(b(i)),2)==1b(i)=1;endenddisp(输入序列：');disp('编码输出序列:');b程序运行结果为：输入序列：a =110 0编码输出序列：b =10 1110 0改变输入序列a=[1 0 1 1],运行结果：输入序列：a =10 11编码输出序列：b =10 0 10 11运行结果的编码如下：译码的实验原理g(x)= 1 x x3，在(n, k)循环码中，由于g(x)能除尽，因此x n T可分解成g(x)和其他因式的乘积，记为x n V g(x)h(x)x n 1g (x)即 h (x) = x 4 X 2 X 〔则h *(x)=x 4 x 3 x 1，其中h *(x)式h(x)的逆多项式。

7.4节循环码

南京邮电大学通信与信息学院
课件制作：朱 10彤
2. 循环码的生成矩阵G
问题生成矩阵 G可由k 个线性无关的码组构成。那么，如何寻找这 k 个
线性无关的码组呢？
定理：线性分组码全0信息码必对应全0校验码。
在(n, k) 循环码的2k个码组中挑出一个前面(k−1)位都是“0”第k位
是1的码组，用g(x)表示。(常数(即末位)不为0、次数最低的非全0码。
g(x)称为循环码的生g(成x) 多项式。
g(x)一旦确定，整个(n, k)循环码就被确定了。它是循环码中唯一的一
个常数不为0的(n−k)次多项式。
南京邮电大学通信与信息学院
课件制作：朱11彤
例
解: r = n–k = 7–3 =4，码组中唯一一个4次码多项式代表的码组是：
0010111 g(x) =x4+x2+x+1
（3）作 a(x) = xn–k m(x)+r(x)
—— 即得循环码的码多项式。(注：对二进制+−等价， r(x)即为校验码)
由上，可得直接构成循环码系统码生成矩阵的方法：
即先求xn−i,(i=1,2,…,k−1)分别除以g(x)的余式，r n−i(x), 从而系统码生
成矩阵为
xn1 rn1(x)
a0 xi
an1xi1
ani
（模(xn + 1)）
所以，这时有
a(x) an1i xn1 an2i xn2 a0 xi an1xi1 ani
显而易见，模(xn + 1)运算的结果是把所有指数大于n的项指数n置于尾部。
将码字用多项式表示是为了利用多项式代数分析、研究编码，并
用其对循环码进行构造、编、译码。

基于MATLAB的(7,4)循环码的编译仿真

Equation Chapter 1 Section 1Harbin Institute of Technology信息论与编码实验报告基于MATLAB的（7，4）循环码的编译仿真院系：电子与信息工程学院姓名：周才发学号：13S005051班级：通信二班哈尔滨工业大学基于MATLAB的（7，4）循环码的编译仿真（电子与信息工程学院13S005051 周才发序号：15）1、循环码简介随着社会经济的迅速发展和科学技术的全面进步，计算机事业的飞速发展，以计算机与通信技术为基础的信息系统正处于蓬勃发展的时期。

随着经济文化水平的显著提高，人们对生活质量及工作软件的要求也越来越高。

在计算机通信信息码中循环码是线性分组码的一个重要子集，是目前研究得最成熟的一类码。

它有许多特殊的代数性质，它使计算机通信以一种以数据通信形式出现，实现了在计算机与计算机之间或计算机与终端设备之间进行有效的与正确地信息传递，它使得现代通信的可靠性与有效性实现了质的飞跃。

它是现代计算机技术与通信技术飞速发展的产物，在日常生活通信领域、武器控制系统等领域都被广泛应用。

纠错码(error correcting code)，在传输过程中发生错误后能在收端自行发现或纠正的码。

仅用来发现错误的码一般常称为检错码。

为使一种码具有检错或纠错能力，须对原码字增加多余的码元，以扩大码字之间的差别，即把原码字按某种规则变成有一定剩余度（见信源编码）的码字，并使每个码字的码之间有一定的关系。

关系的建立称为编码。

码字到达收端后，可以根据编码规则是否满足以判定有无错误。

当不能满足时，按一定规则确定错误所在位置并予以纠正。

纠错并恢复原码字的过程称为译码。

检错码与其他手段结合使用，可以纠错。

纠错编码又称信道编码，它与信源编码是信息传输的两个方面。

它们之间存在对偶的关系。

应用信道译码直接对一些自然信息进行处理，可以去掉剩余度，以达到压缩数据的目的。

为了使一种码具有检错或纠错能力，必须对原码字增加多余的码元，以扩大码字之间的差别，使一个码字在一定数目内的码元上发生错误时，不致错成另一个码字。

信息论(7,4)汉明码(7,3)循环码

functionvarargout = Hamming(varargin)% HAMMING M-file for Hamming.fig% HAMMING, by itself, creates a new HAMMING or raises the existing % singleton*.%% H = HAMMING returns the handle to a new HAMMING or the handle to % the existing singleton*.%% HAMMING('CALLBACK',hObject,eventData,handles,...) calls thelocal% function named CALLBACK in HAMMING.M with the given input arguments. %% HAMMING('Property','Value',...) creates a new HAMMING or raises the % existing singleton*. Starting from the left, property value pairs are% applied to the GUI before Hamming_OpeningFunction gets called. An % unrecognized property name or invalid value makes property application% stop. All inputs are passed to Hamming_OpeningFcn via varargin. %% *See GUI Options on GUIDE's Tools menu. Choose "GUI allows only one% instance to run (singleton)".%% See also: GUIDE, GUIDATA, GUIHANDLES% Edit the above text to modify the response to help Hamming% Last Modified by GUIDE v2.5 07-Jan-2008 20:22:48% Begin initialization code - DO NOT EDITgui_Singleton = 1;gui_State = struct('gui_Name', mfilename, ...'gui_Singleton', gui_Singleton, ...'gui_OpeningFcn', @Hamming_OpeningFcn, ...'gui_OutputFcn', @Hamming_OutputFcn, ...'gui_LayoutFcn', [] , ...'gui_Callback', []);ifnargin&&ischar(varargin{1})gui_State.gui_Callback = str2func(varargin{1});endifnargout[varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});elsegui_mainfcn(gui_State, varargin{:});end% End initialization code - DO NOT EDIT% --- Executes just before Hamming is made visible.functionHamming_OpeningFcn(hObject, eventdata, handles, varargin)% This function has no output args, see OutputFcn.% hObject handle to figure% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% varargin command line arguments to Hamming (see VARARGIN)% Choose default command line output for Hamminghandles.output = hObject;% Update handles structureguidata(hObject, handles);% UIWAIT makes Hamming wait for user response (see UIRESUME)% uiwait(handles.figure1);% --- Outputs from this function are returned to the command line. functionvarargout = Hamming_OutputFcn(hObject, eventdata, handles)% varargout cell array for returning output args (see VARARGOUT);% hObject handle to figure% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Get default command line output from handles structurevarargout{1} = handles.output;function edit1_Callback(hObject, eventdata, handles)% hObject handle to edit1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit1 as text% str2double(get(hObject,'String')) returns contents of edit1 as a double% --- Executes during object creation, after setting all properties. function edit1_CreateFcn(hObject, eventdata, handles)% hObject handle to edit1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit2_Callback(hObject, eventdata, handles)% hObject handle to edit2 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit2 as text% str2double(get(hObject,'String')) returns contents of edit2 as a double% --- Executes during object creation, after setting all properties. function edit2_CreateFcn(hObject, eventdata, handles)% hObject handle to edit2 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit3_Callback(hObject, eventdata, handles)% hObject handle to edit3 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit3 as text% str2double(get(hObject,'String')) returns contents of edit3 as a double% --- Executes during object creation, after setting all properties. function edit3_CreateFcn(hObject, eventdata, handles)% hObject handle to edit3 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit4_Callback(hObject, eventdata, handles)% hObject handle to edit4 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit4 as text% str2double(get(hObject,'String')) returns contents of edit4 as a double% --- Executes during object creation, after setting all properties. function edit4_CreateFcn(hObject, eventdata, handles)% hObject handle to edit4 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit5_Callback(hObject, eventdata, handles)% hObject handle to edit5 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit5 as text% str2double(get(hObject,'String')) returns contents of edit5 as a double% --- Executes during object creation, after setting all properties. function edit5_CreateFcn(hObject, eventdata, handles)% hObject handle to edit5 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit6_Callback(hObject, eventdata, handles)% hObject handle to edit6 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit6 as text% str2double(get(hObject,'String')) returns contents of edit6 as a double% --- Executes during object creation, after setting all properties. function edit6_CreateFcn(hObject, eventdata, handles)% hObject handle to edit6 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');end% --- Executes on button press in pushbutton1.function pushbutton1_Callback(hObject, eventdata, handles)% hObject handle to pushbutton1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)chose=get(handles.popupmenu1,'value');if chose==1;clc;msg=str2num(get(handles.edit1,'string'))%信息产生code=encode(msg,7,4);%汉明编码rcv=decode(code,7,4);%汉明译码set(handles.edit2,'string',num2str(code));set(handles.edit3,'string',num2str(rcv));elsek=str2num(get(handles.edit1,'string'));code1=encode(k,7,3,'cyclic/binary');rcv1=decode(code1,7,3,'cyclic/binary');set(handles.edit2,'string',num2str(code1));set(handles.edit3,'string',num2str(rcv1));endfunction edit7_Callback(hObject, eventdata, handles)% hObject handle to edit7 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit7 as text% str2double(get(hObject,'String')) returns contents of edit7 as a double% --- Executes during object creation, after setting all properties. function edit7_CreateFcn(hObject, eventdata, handles)% hObject handle to edit7 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit8_Callback(hObject, eventdata, handles)% hObject handle to edit8 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit8 as text% str2double(get(hObject,'String')) returns contents of edit8 as a double% --- Executes during object creation, after setting all properties. function edit8_CreateFcn(hObject, eventdata, handles)% hObject handle to edit8 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit9_Callback(hObject, eventdata, handles)% hObject handle to edit9 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit9 as text% str2double(get(hObject,'String')) returns contents of edit9 asa double% --- Executes during object creation, after setting all properties. function edit9_CreateFcn(hObject, eventdata, handles)% hObject handle to edit9 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit10_Callback(hObject, eventdata, handles)% hObject handle to edit10 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit10 as text% str2double(get(hObject,'String')) returns contents of edit10 as a double% --- Executes during object creation, after setting all properties. function edit10_CreateFcn(hObject, eventdata, handles)% hObject handle to edit10 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction edit15_Callback(hObject, eventdata, handles)% hObject handle to edit15 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of edit15 as text% str2double(get(hObject,'String')) returns contents of edit15 as a double% --- Executes during object creation, after setting all properties. function edit15_CreateFcn(hObject, eventdata, handles)% hObject handle to edit15 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');end% --- Executes on button press in pushbutton2.function pushbutton2_Callback(hObject, eventdata, handles)% hObject handle to pushbutton2 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)chose=get(handles.popupmenu1,'value');if chose==1;[H,G,N,K]=hammgen(3); %产生H和G矩阵for i=1:2^Kfor j=K:-1:1if rem(i-1,2^(-j+K+1))>=2^(-j+K)U(i,j)=1;elseU(i,j)=0;endendendC=rem(U*G,2);A=str2num(get(handles.edit7,'string'));[r,l]=size(A);E=[0 0 0 0 0 0 0;0 0 0 0 0 0 1;0 0 0 0 0 1 0;0 0 0 0 1 0 0;0 0 0 1 0 00;0 0 1 0 0 0 0;0 1 0 0 0 0 0;1 0 0 0 0 0 0]; %%%%%求校正子，然后将其转化成十进制数S=rem(A*H',2);Sx=bi2de(S,'left-msb');%%%%下面是（7,4）码检错for i=1:rswitch(Sx)case 0disp=('此接收码字没错')case 1disp=('注意：此接收码字的第3位有错，请纠正')case 2disp=('注意：此接收码字的第2位有错，请纠正')case 4disp=('注意：此接收码字的第1位有错，请纠正')case 3disp=('注意：此接收码字的第5位有错，请纠正')case 5disp=('注意：此接收码字的第7位有错，请纠正')case 6disp=('注意：此接收码字的第4位有错，请纠正')case 7disp=('注意：此接收码字的第6位有错，请纠正')endendset(handles.edit8,'string',disp);%%%下面为在知道哪位出错的情况下，进行纠正for i=1:rswitch(Sx)case 0B(i,:)=A(i,:)+E(1,:);case 1B(i,:)=A(i,:)+E(6,:);case 2B(i,:)=A(i,:)+E(7,:);case 4B(i,:)=A(i,:)+E(8,:);case 3B(i,:)=A(i,:)+E(4,:);case 5B(i,:)=A(i,:)+E(2,:);case 6B(i,:)=A(i,:)+E(5,:);case 7B(i,:)=A(i,:)+E(3,:);endendB=rem(B,2);set(handles.edit9,'string',num2str(B));elsegenpoly=cyclpoly(7,3);[p,g]=cyclgen(7,genpoly);c=str2num(get(handles.edit7,'string'));s=rem(p*c',2);Sx=s(1,1)+s(2,1)*2+s(3,1)*4+s(4,1)*8;switch(Sx)case 0set(handles.edit8,'string','此接收碼无错');set(handles.edit9,'string',num2str(c));case 1if c(1,1)==0c(1,1)=1;elsec(1,1)=0endset(handles.edit8,'string','注意：此接收码字的第一位有错，请纠正');set(handles.edit9,'string',num2str(c));case 2if c(1,2)==0c(1,2)=1;elsec(1,2)=0endset(handles.edit9,'string',num2str(c));set(handles.edit8,'string','注意：此接收码字的第二位有错，请纠正');case 4if c(1,3)==0c(1,3)=1;elsec(1,3)=0endset(handles.edit9,'string',num2str(c));set(handles.edit8,'string','注意：此接收码字的第三位有错，请纠正');case 8if c(1,4)==0c(1,4)=1;elsec(1,4)=0endset(handles.edit9,'string',num2str(c));set(handles.edit8,'string','注意：此接收码字的第四位有错，请纠正');case 13if c(1,5)==0c(1,5)=1;elsec(1,5)=0endset(handles.edit9,'string',num2str(c));set(handles.edit8,'string','注意：此接收码字的第五位有错，请纠正');case 7if c(1,6)==0c(1,6)=1;elsec(1,6)=0endset(handles.edit9,'string',num2str(c));set(handles.edit8,'string','注意：此接收码字的第六位有错，请纠正');case 14if c(1,7)==0c(1,7)=1;elsec(1,7)=0endset(handles.edit9,'string',num2str(c));set(handles.edit8,'string','注意：此接收码字的第七位有错，请纠正');case{3,5,6,9,10,11,12,15}set(handles.edit8,'string','注意：此接收码字有错');set(handles.edit9,'string','注意：无法纠正无法判别错在哪位'); endend% --- Executes on selection change in popupmenu1.function popupmenu1_Callback(hObject, eventdata, handles)% hObject handle to popupmenu1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: contents = get(hObject,'String') returns popupmenu1 contents as cell array% contents{get(hObject,'Value')} returns selected item from popupmenu1% --- Executes during object creation, after setting all properties. function popupmenu1_CreateFcn(hObject, eventdata, handles)% hObject handle to popupmenu1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: popupmenu controls usually have a white background on Windows. % See ISPC and COMPUTER.ifispc&&isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');end。