We discuss the theory and technology of coding and cryptology in the study of information security and information reliability in the disseration . some valuable theoretic results are presented , most of these results are published on the important journey of china , parts of these results are used in some application system . in the design and analysis of error - correcting codes , we obtain the following results 本文探讨了信息安全和信息可靠性研究中的编码密码理论与技术，在纠错码的设计与分析、序列密码的设计与分析以及分组密码的设计与分析等方面，得到了一些有价值的理论结果，大多数结果已在国内核心刊物上发表，有些结果已用于实际的应用系统。
Chapter is the most important part in this paper , we used pulse position modulation ( ppm ) and maxim - likelihood demodulation to increase the power efficiency , improve the ber , also we used rs ( reed - solomon ) code to correct the bunched bit error because of the atmosphere scintillation . with the ppm modulation / ml demodulation method and rs code , the performance of the system improved to a new stage 第四章是对无线光接入的调制解调和编码技术的分析，也是本文的重点，比较了ppm调制和ook调制的带宽和功率利用率、硬判决解调和最大似然解调对系统性能的改善，以及采用rs纠错码对系统性能的改善。
In the first chapter , the basis of communication and channel coding theory is introduced briefly , the present situation of the development of error - correcting code and ldpc codes are pointed out . the second chapter introduces the tdd beyond 3g system model , including the system ’ s demand , the system ’ s target and the system ’ s basic parameter 第一章介绍了通信系统、信道编码理论的基础知识、纠错码的发展状况, ldpc码的提出及其发展,第二章介绍了我校设计的tddbeyond3g系统模型,包括系统的设计要求、指标及系统的基本参数。
The proposed md mesh - based motion coding methodis then combined with the pairwise correlating transform , and acomplete md video coding scheme is proposed . further measures are takento reduce the mismatch between the encoder and decoder that occurs whenonly one description is received and the decoder reconstruction isdifferent from the encoder . the performance of the proposed scheme isevaluated using computer simulations , and the results show , compared toreibman s md transform coding mdtc method , the proposed schemeachieves better redundancy rate distortion performance 数据重传必然会引起延迟，因而在需要很短延迟的应用中是行不通的，如双向无线通信同时在以广播方式进行数据传输时也是行不通的当有大量突发错误时，纠错码如分组纠错码block code及卷积码convolutional code无法在不产生额外延迟及需要额外运算的前提下对数据提供足够的保护而错误掩蔽的性能则受接收到数据与丢失数据之间的残留相关性大小的影响。
Since 1980s , many mathematicians have been engaged in studying the applications of the grobner basis such as solving the system of algebraic equations , factoring polynomials , testing primary ideals , factoring algebraic manifolds , decoding circular codes in corrected codes and algebraically geometrical codes , analyzing and synthesizing high dimensional linear recurring arrays in cryptology , dealing with multidimensional systematic theory , signaling , solving integer programming and so on ) bner基的应用研究包括代数方程组求解，多项式的因子分解，素理想的检验，代数流形的分解，纠错码中循环码和代数几何码的译码，密码学中高维线性递归阵列的分析与综合，多维系统理论，信号处理和求解整数规划等诸多领域。
Our object is an intermediate frequency modem of a software defined radio transmitter - receiver of multi - service , multi - modulationmode and multi - processdatarate . first , related software defined radio theory is introduced ; later , channels of transmitter - receiver are designed with consideration of data format , modulation , fec , interwaving . and scrambling ; emphasis is placed on theory and implementation of an audio compression algorithm cvsd ( continuous variable slope delta modulation ) and a fec technique convolutional coding - decoding 本文首先介绍了相关的软件无线电理论；然后完成了包括数据格式，调制方式，纠错码方式，交织器和扰码器等部分的中频调制解调器通道设计；接着着重介绍了系统中使用的音频压缩算法cvsd (连续可变斜率增量调制)的原理和实现，以及作为前向纠错码的卷积码编码理论和编解码的高效实现。
