信息论实验报告.docx
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信息论实验报告
信息论与编码实验报告
学校：
中国地质大学（武汉）
指导老师：
姓名：
班级序号：
071112-11
日期：
2013年11月30日
1.LempelZiv字典编码····································3
题目要求·······························································3
程序流程·······························································3
核心步骤·······························································4
程序代码·······························································5
测试结果·······························································9
效果分析及改进建议····················································11
2.信道容量计算···········································12
题目要求·······························································12
程序流程·······························································12
核心步骤·······························································13
程序代码·······························································13
测试结果·······························································13
效果分析·······························································14
3.汉明码的编码与解码····································14
题目要求·······························································14
程序流程·······························································14
核心步骤·······························································15
程序代码·······························································15
测试结果·······························································18
效果分析及改进建议·····················································19
4.循环码的生成与最小距离计算····························19
题目要求·······························································19
程序流程·······························································19
核心步骤·······························································20
程序代码·······························································20
测试结果·······························································23
效果分析·······························································23
5.卷积码的编码与解码····································24
题目要求·······························································24
程序流程·······························································25
核心步骤·······························································25
程序代码·······························································25
测试结果·······························································31
效果分析及改进建议·····················································32
6.上机总结···············································33
1.LempelZiv字典编码
题目要求
WriteaprogramthatexecutestheLempelZivalgorithm.TheinputtotheprogramcanbetheEnglishalphabets.ItshouldconvertthealphabetstotheirASCIIcodeandthenperformthecompressionroutine.Itshouldoutputthecompressionachieved.Usingthisprogram,findoutthecompressionachievedforthefollowingstringsofletters.
（i）TheLempelZivalgorithmcancompresstheEnglishtextbyaboutfiftyfivepercent.
（ii）Thecatcannotsitonthecanopyofthecar.
程序流程
1.编码算法：
N
Y
2.解码算法与编码恰好相反（略）：
核心步骤
1.构造字典，初始字典中应包含1-256所有ASIIC码对应的字符；
2.分清字典编号和字符的关系：
编码时始终对字符和字符串进行操作，但发送的始终是对应的字典编号。
解码时始终对字典编号进行操作，但输出的是编号对应字符。
3.编写相关函数，实现对字典的基本操作，如：
添加新字符、字符串拼接、查找某个编号对应的字符、查找某个字符串对应的编号；
4.在字典中添加，Newchar:
，Link...，以便对字典进行操作
程序代码
1.构建字典：
function[new_dic]=Creat_newdic（）
%构建初始字典
%使用说明：
%new_dic=Creat_newdic（）;
new_dic=zeros（512,30）;
new_dic=uint8（new_dic）;
fori=1:
256
new_dic（i,1）=i;
end
new_dic=char（new_dic）;
new_dic（257,1:
8）='Newchar:
';
new_dic（258,1:
7）='Link...';
end
2.向字典里添加新字符串：
function[dic_out,flag]=Add_newstr（dic_in,newstr）
%向字典添加新字符串
%使用方法
%[dic_out,flag]=Add_newstr（dic_in,newstr）
dic_out=dic_in;
L=size（newstr）;
flag=1;
position=Search_str（dic_in,'Link...'）;
ifposition==512
flag=0;return;
end
dic_out（position,:
）=0;
dic_out（position,1:
L
（2））=newstr;
dic_out（position+1,1:
7）='Link...';
end
3.取出字典里某个位置的字符串：
function[str]=Get_str（dic,position）
%取出某字典中的指定位置的字符串
%使用说明：
%str=Get_str（dic,position）;
%L=size（dic（position,:
））;
fori=1:
30
if（dic（position,i）~=0）
N=i;
else
break;
end
end
str（1:
N）=dic（position,1:
N）;
end
4.在指定的字典里查找某个字符串：
function[position]=Search_str（dic,str）
%在字典中查找某字符串
[M,N]=size（str）;
position=0;
fori=1:
512
ifdic（i,1:
N）==str
position=i;
break;
end
end
end
5.将两个字符串相加：
function[position]=Search_str（dic,str）
%在字典中查找某字符串
[M,N]=size（str）;
position=0;
fori=1:
512
ifdic（i,1:
N）==str
position=i;
break;
end
end
end
6.编码过程：
function[code_out,dic_out]=LZ_coding（dic_in,str）
%字典编码之发送端
%Detailedexplanationgoeshere
dic_out=dic_in;
[M,N]=size（str）;
counter=1;
ifN==0
code_out（counter）=Search_str（dic_out,'Newchar:
'）;
counter=counter+1;
code_out（counter）=Search_str（dic_out,'Link...'）;
retu
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