辅导交流
地 址:西安市科技路JR电子科技
3127247860:点击这里给我发消息
2733195595:点击这里给我发消息
电 话:13649286003
邮 箱:jr_dz_kj@163.com
当前位置:首页主页 >> 论文展示 >>
数字通信系统帧同步设计及可靠性研究
作者:admin   发布于:2014-03-05 20:28    文字:【】【】【
 摘要
在数字通信过程中,同步系统作为一项关键的技术,起着至关重要的作用。在正常的数据传输过程中,只有收发双方之间建立了同步才能准确地传输信息,因此要求同步信息传输的可靠性高于信号传输的可靠性。随着信道编解码技术的提高,信道误码率的降低,对帧同步的要求也越来越高。因为帧同步作为信道解码的前提条件,在不能识别帧同步码字的情况下,也就找不到帧的起始位置,信道解码是无法进行的,信道编解码系统也就失去了作用。
    本文首先介绍了帧同步技术的基本原理。最大似然判决算法是在每一帧前插入一个具有良好自相关性的同步码,如巴克码等,然后接收端在比特流中的各个候选位置与同步码计算相关,将相关值最大的位置判决为同步码的位置。根据帧同步技术的原理,本文在分析低压电力线载波通信特点的基础上,通过使用MATLAB软件仿真数字通信帧同步系统,对现有的电力线载波信道数据帧同步技术中帧同步码长度和码型方案进行分析、比较。设计出一种电力线载波自动抄表系统的数据帧同步方案。
    本文还在理论研究的基础上对仿真数据结果进行了必要的分析,通过图表对比理论值和实际值的整体变化趋势,得出了具体码字在具体判决门限性能,能够给实际工程带来帮助。
 
关键词: 数字通信系统  数据帧同步  MATALB
 
 
 
 
 
 
 
 
 

ABSTRACT

Synchronization system, as a key technique, is particularly important in the process of digital communication .In the normal data transmission, the information is transferred correctly only when the receiver and sender are synchronous, so the reliability of synchronization transfer information must be higher than that of signal transfer in-formation. With the improvement of channel encoding technique and the decrease of channel error-code rate, the need for frame synchronization is higher and higher. Be-cause the frame synchronization is the precondition of the channel decoding, the be-ginning place of the frame synchronization could not be found and the channel de-coding could not be progressed on the condition that the frame synchronization codeword could not be recognized, thus it is meaningless to the channel decoding system.
    In this paper, the basic theory of frame synchronization technique is explained first. The maximum likelihood (ML) decoding algorithm is to insert a good dependent synchronization code before each transfer frame, such as Barker codes, and then compute the dependent of synchronization code and candidate place o bit stream in the receiving end, finally consider the biggest place as the synchronization code place. Based on the theory of frame synchronization and the characteristic of power line communication, By using MATLAB to simulate the system, and analyzing the result. Devise a system be becoming to power line communication.
    In this article, the simulation result is analyzed based on the theoretical research. The just codeword and performance of the decision threshold is proposed through the changing trend by contrasting the theoretical value to the true value in the graph, and it is helpful to the practical engineering.
 
Keywords:    digital communication system   data frame synchronization      
                            MATALB

目 录

第一章  绪论.................................................. 1
1.1  课题研究现状................................................... 1
1.2  课题研究的目的和意义........................................... 1
第二章 低压电力线信道分析..................................... 3
2.1低压电力线衰减特性.............................................. 3
2.2低压电力线上的噪声.............................................. 4
2.2.1  电力线通信信道特点........................................ 4
2.2.2  电力线噪声及其分布........................................ 4
2.3 低压电力线高频通信下的阻抗特性................................. 9
第三章  帧同步技术........................................... 11
3.1常用的帧同步法................................................. 11
3.1.1  起止式同步法............................................. 11
3.1.2  连贯式插入法............................................. 12
3.1.3  间隔式插入法............................................. 16
3.2 群同步系统的性能指标.......................................... 19
3.2.1  漏同步概率P1............................................. 19
3.2.2  假同步概率............................................... 20
3.2.3  群同步平均建立时间ts..................................... 20
3.3 群同步的保护.................................................. 20
第四章  同步码循环相关检测技术................................ 23
4.1.循环自相关算法................................................ 23
4.1.1  基本理论................................................. 23
4.1.2   算法提出................................................ 24
4.2.循环互相关函数................................................ 28
4.3.循环互相关运算的MATLAB实现................................... 29
4.3.1  循环互相关运算的MATALB的实现过程........................ 29
4.3.2  其他相关问题............................................. 30
第五章  帧同步技术及可靠性研究................................ 33
5.1位同步信号的性能要求........................................... 33
5.2位同步信号的提取方法........................................... 33
5.3 数字位同步系统结构............................................ 33
5.4 位同步对数字通信系统的影响.................................... 34
致  谢...................................................... 37
参考文献.................................................... 39


附件一 附件二
友情链接