前向纠错技术中卷积交织器的FPGA实现

介绍了信道编码中所采用的前向纠错编码（FEC）方案中的重要技术——卷积交织器和解交织器的原理,并在此基础上提出了基于FPGA的卷积交织器的设计方案。丈中对卷积交织器设计的关键部分,即读写地址的产生方法进行了详细分析,给出了一种新的地址计算方法,并通过对FPGA内部EAB资源的双口RAM的存储单元的读写操作的合理控制,实现了卷积交织。该设计具有实现简单、占硬件资源少等优点。     

卷积交织器和解交织器的VHDL设计和FPGA实现

介绍了信道编码中所采用的前向纠错编码(FEC)方案中的重要技术——卷积交织器和解交织器的原理，并在此基础上提出了一种VHDL设计和FPGA实现方案，给出了具体的实现方法，该方法具有实现简单和占用资源少的优点。     

DVB-T调制器外码编码器的FPGA设计

设计并实现了一种DVB—T调制器的外码编码器，着重介绍了码流自适应接口、能量扩散、RS编码器及卷积交织器的设计方法，该设计方案最终在Altera的FPGA上进行验证。     

一种基于FPGA的Turbo码译码器的设计

主要论述了一种基于FPGA的Turbo码译码器的设计。首先简单介绍了编码器和交织器的原理;然后介绍了基于Max-Log-MAP算法的译码器原理,详细论述了各个子模块;最后给出了系统仿真的误码率图形。     

Turbo码中交织器和子码的综合设计

分析了距离谱和交织器结构对 Ｔｕｒｂｏ码性能的影响，介绍了高斯信道中一种新的 Ｔｕｒｂｏ码设计方法。该方法对交织器及子码进行综合设计，并给出了交织器的设计方法。仿真结果表明，通过交织器和子码的综合设计可以获得优异的误比特率性能。     

基于FPGA的Turbo码译码器的设计

主要论述了一种基于FPGA的Turbo码译码器的设计。首先简单介绍了编码器和交织器的原理;然后介绍了基于Max-Log-MAP算法的译码器原理,对分量译码器做了详细论述,给出了各子模块原理和ModelSim仿真图形;最后给出了系统仿真的误码率图形。     

CDMA2000中信号交织器的设计与仿真

为了提高低信噪比情况下系统的纠错能力,Turbo码作为通信传输系统中的一种新兴的信道纠错编码技术,逐渐成为了信息编码界的研究热点。交织器是Turbo码编、译码器的重要组成部件。本设计对CDMA2000中的Turbo交织器进行了介绍,设计了交织器模块,并通过MATLAB进一步对交织器的应用进行了仿真。     

一种基于MATLAB的Turbo码编码仿真实现

介绍了CDMA2000系统中Turbo码的编码原理和通过MATLAB实现编码仿真的关键元件和技术-交织器、抽样器以及交织器的实现过程，仿真结果表明,可以用数据输出长度来衡量编码器的有效性。     

基于DMB-TH标准的FEC编码器的设计

本文设计了一种符合数字地面广播电视（DMB—TH）标准的前向纠错码（FEC）编码器。设计中BCH编码器采用了10比特并行的编码方式,大大提高了BCH编码的速度。LDPC的编码则以信息位的移位代替生成矩阵的移位,使得在结构和存储空间上得到很大的优化。     

ATSC数字电视标准中Trellis编码器及解交织器的FPGA实现

介绍了信道编码中网格编码调制和交织编码的基本原理,重点介绍了以上两种ATSC数字电视标准下的具体实现方法,并着重讨论了Trellis编码器以及解交织器的FPGA硬件实现。     

基于改进2-DGRS码的QC-LDPC码高效构造

利用GRS(generalized reed-solomon)码的生成多项式提出了基于改进的2-D GRS(two-dimensional GRS)码设计和构造QC-LDPC(quasi-cyclic low density parity-check)码的方法,使所构造的码具有较好的译码性能。同时在码的构造过程中,考虑到了准双对角线结构和合适的度分布。不同码率的LDPC码用于和新设计的QC-LDPC码进行测试和比较。实验结果表明,所提出的码构造方法可加快LDPC码校验矩阵的构造,同时基于所提出方法构造的QC-LDPC码可提高译码性能,并降低编码复杂度。     

OCDMA中一种新的多倍长多波长RS码

提出了一种新的容量大、相关性好的多倍长、多波长reed-solomon（MW RS）码编码方案,并构造了多倍长MW RS码.对同时使用具有两种码长的多倍长MW RS码的OCDMA系统性能分析表明,使用该多倍长MW RS码的系统性能良好,使用短码序列信号的误码率性能好于使用长码序列信号的误码率性能.该特征能满足将来大容量多媒体OCDMA网络系统对同时传输的不同速率信号所需传输质量不同的需求.     

基于知识库的雷达辐射源识别专家系统

从分析雷达辐射源识别的特点出发，提出了基于知识库的雷达辐射源识别专家系统。讨论了系统总体结构模型和面向对象模型。根据系统要求建立了数据库；积累案例形成案例库；获取专家经验及领域知识建立了规则库；依据知识层次结构建立了模型库，这四库一体化形成专家系统。介绍了基于案例、基于规则和基于模型的推理方法，比较了各种推理方法的优、缺点，并提出了基于案例、规则和模型的混合推理。最后给出了系统的功能和实现方法。应用证明基于知识库的雷达辐射源识别专家系统可以得到与专家同样的结果。     

Performance of chip-interleaving DS SS system with nonlinearity under pulsed interference

Analytical bit error rate (BER) results of a chip-interleaving direct sequence (DS) spread spectrum (SS) system using nonlinearity in the presence of pulsed interference are presented. Several simple nonlinearities, such as hole puncher, soft clipper, and hard limiter nonlinearities, are studied. The BERs of a conventional DS SS system employing the same nonlinearities are also given. The proposed system is compared with the conventional DS SS system using numerical examples.     

Ternary State Circular Sequential k-out-of-n Congestion System

A ternary state circular sequential k-out-of-n congestion (TSCSknC) system is presented. The system is an extension of the circular sequential k-out-of-n congestion (CSknC) system which consists of two connection states: a) congestion (server busy), and b) successful. In contrast, a TSCSknC system considers three connection states: i) congestion, ii) break down, and iii) successful. It finds applications in some reliable systems to prevent single-point failures, such as the ones used in (k,n) secret key sharing systems. The system further assumes that each of the n servers has known connection probabilities in congestion, break-down, and successful states. These n servers are arranged in a circle, and are made with connection attempts sequentially round after round. If a server is not congested, the connection can be either successful, or a failure. Previously connected servers are blocked from reconnecting if they were in either states ii), or iii). Congested servers are attempted repeatedly until k servers are connected successfully, or (n-k+1) servers have a break-down status. In other words, the system works when k servers are successfully connected, but fails when (n-k+1) servers are in the break-down state. In this paper, we present the recursive, and marginal formulas for the system successful probability, the system failure probability, as well as the average stop length, i.e. number of connections needed to terminate the system to a successful or failure state, and its computational complexity.     

Consequence and impact of electric utility industry restructuringon transient stability and small-signal stability analysis

The electric utility industry is undergoing unprecedented changes in its structure worldwide. With the advent of an open market environment and competition in the industry, and restructuring of the industry into separate generation, transmission, and distribution entities, new issues in power system operation and planning are inevitable. One of the major consequences of this new electric utility environment is the greater emphasis on reliability and secure operation of the power system. This paper examines the impact of restructuring on power system dynamic analysis. It specifically addresses issues related to transient stability analysis and small-signal stability analysis. Four major topics to examine the effect on the nature of studies conducted are considered. These topics are: (1) system adequacy and security, (2) system modeling data requirements, (3) system protection and control, and (4) system restoration. The consequences and impact of each of these topics on the nature of the studies conducted are examined and discussed. The emphasis on greater reliability has led to a clearer enunciation of standards, measurements, and guides in some countries. These requirements will result in: (1) more measurements on existing systems, (2) rigorous analysis of transient stability and small-signal stability to determine operating limits and plan systems, (3) greater emphasis on studies to verify coordination and proper performance of protection and controls, and (4) development of a detailed plan for system restoration in the case of wide-spread outages     

Analytical approximation of the generalized ambiguity function of the MIMO synthetic-aperture radar system

The generalized ambiguity function in spatial coordinates and its approximate analytical representation are obtained for the multifrequency multiple-input multiple-output (MIMO) synthetic-aperture radar (SAR) system. The examples in which ambiguity-function cross sections in range and azimuth are calculated in the Earth remote sensing problem for the MIMO SAR system installed on a spacecraft and compared with those for the classical SAR system are presented. In the case of the MIMO SAR system, the physical meaning and the practical importance of an increase in azimuthal resolution are explained.     

可见光化学激光研究Ⅰ.电子跃迁氟化碘化学激光探索

研究了三种可以获得电子激发态IF的超音速流动反应体系:(F+F_2+IF)、NH_3体系,(F+F_2)、(NH_3+CF_3I)体系及(F+F_2)、NH_3、RI体系.记录到了IF B→X荧光光谱.提出了上述三种反应体系产生IF(B)的机制.讨论了研制IF化学激光器的前景.     

Interval Reliability for Initiating and Enabling Events

This paper describes generation and evaluation of logic models such as fault trees for interval reliability. Interval reliability assesses the ability of a system to operate over a specific time interval without failure. The analysis requires that the sequence of events leading to system failure be identified. Two types of events are described: 1) initiating events (cause disturbances or perturbations in system variables) that cause system failure and 2) enabling events (permit initiating events to cause system failure). Control-system failures are treated. The engineering and mathematical concepts are described in terms of a simplified example of a pressure-tank system. Later these same concepts are used in an actual industrial application in which an existing chlorine vaporizer system was modified to improve safety without compromising system availability. Computer codes that are capable of performing the calculations, and pitfalls in computing accident frequency in fault tree analysis, are discussed.