市级台站无人值守机房光纤信号的搭建与思考

针对市级台站无人值守机房光纤信号源相关问题的解决,结合目前市级台站布局及光纤路由现状,在综合考虑业务发展并利用现有资源的基础上,以扬州台“江苏健康广播”光纤信号源的搭建为例,阐述市级台站无人值守机房光纤信号源的设计思路,并对相应的交换机、解码器的具体配置进行简单介绍,同时对该方案进行分析与思考,证明此设计方案的可靠性及稳定性,将其应用在市级台站无人值守机房光纤信号源上是行之有效的.     

CMOS三值译码器

本文探讨了在常规CMOS集成电路基础上设计三值逻辑电路的方法。从三值倒相器入手,结合常规CMOS门电路,给出了CMOS三值译码器的设计方案及应用电路。     

Performance analysis and simulation of OCDMA system based on FBGs encoder/decoder

The encoding/decoding scheme based on Fiber Bragg Grating （FBG） for Optical Code Division Multiple Access （OCDMA） system is analyzed and the whole process from transmitting end to receiving end is researched in detail. The mathematical mode including signal transmission, summing, receiving and recovering are established respectively. One of the main sources of Bit Error Rate （BER） of OCDMA system based on FBGs is the unevenness of signal power spectrum, which leads to the chip powers unequal with each other. The Signal to Interfere Ratio （SIR） and BER performance of the system are studied and simulated at the case with uneven distribution of chips＇ powers.     

Instance-optimality in probability with an -minimization decoder

Let Φ(ω), ωΩ, be a family of n×N random matrices whose entries _i,j are independent realizations of a symmetric, real random variable η with expectation and variance . Such matrices are used in compressed sensing to encode a vector by y=Φx. The information y holds about x is extracted by using a decoder . The most prominent decoder is the ℓ₁-minimization decoder Δ which gives for a given the element which has minimal ℓ₁-norm among all with Φz=y. This paper is interested in properties of the random family Φ(ω) which guarantee that the vector will with high probability approximate x in to an accuracy comparable with the best k-term error of approximation in for the range kan/log₂(N/n). This means that for the above range of k, for each signal , the vector satisfies

with high probability on the draw of Φ. Here, Σ_k consists of all vectors with at most k nonzero coordinates. The first result of this type was proved by Wojtaszczyk [P. Wojtaszczyk, Stability and instance optimality for Gaussian measurements in compressed sensing, Found. Comput. Math., in press] who showed this property when η is a normalized Gaussian random variable. We extend this property to more general random variables, including the particular case where η is the Bernoulli random variable which takes the values with equal probability. The proofs of our results use geometric mapping properties of such random matrices some of which were recently obtained in [A. Litvak, A. Pajor, M. Rudelson, N. Tomczak-Jaegermann, Smallest singular value of random matrices and geometry of random polytopes, Adv. Math. 195 (2005) 491–523].     

复杂环境下低信噪比WCDMA信号接收系统总体设计

根据区域内移动通信网信号接收的需求,提出了一种复杂环境下 低信噪比WCDMA移动通信信号接收系统的总体设计方案,针对关键环节小区搜索采用了差分 相干累积和RS译码判决等改进措施,提高了低信噪比WCDMA信号的处理性能。仿真和实验证 明了改进措施的有效性。     

802.11b中卷积码和Viterbi译码的FPGA设计实现

卷积码是一种重要的信道纠错编码方式,其纠错性能通常优于分组码,目前(2,1,6)卷积码已广泛应用于无线通信系统中,Viterbi译码算法能最大限度地发挥卷积码的纠错性能。阐述了802.11b中卷积码的编码及其Viterbi译码方法,给出了编译码器的设计方法,并利用Verilog HDL硬件描述语言完成编译码器的FPGA实现。使用逻辑分析仪,在EP2C5T144C8芯片上完成了编译码器的硬件调试。     

一种改进的汉明码译码器设计与FPGA验证

提出了一种汉明码译码器改进方法,采用串行数据传输和时序优化的方法来降低汉明码译码器占用的资源和成本,并采用模块式的设计方法,设计了编译码系统仿真平台,详细地阐述了整个系统和各个模块的FPGA实现过程.仿真结果表明,设计的译码器复杂度明显降低.     

基于单片机的HDB3编/译码器的设计与实现

介绍了一种基于单片机的HDB3编/译码器的设计.以常用的51系列单片机为核心,结合外围电路,实现了HDB3编/译码器的功能.在单片机应用系统之间的数字基带通信中,具有一定的应用前景.     

GSM网络监测系统Abis接口信令的解码研究与实现

随着网络不断的成熟和网络承载业务量的不断增加,基于站址,站群的优化变得越来越困难。Abis接口的监测对于GSM,GPRS网优具有独特的优势。文章着重对Abis接口协议栈进行分析,并对该接口消息的解码方法进行了研究,提出GSM网络监测系统Abis接口解码模块设计的总体方案。最终的测试结果表明,该系统运行稳定且解码效率高。     

基于MIPS处理器的AMR-WB语音解码器优化

在分析自适应多速率宽带语音编码标准（AMR-WB）编解码技术的基础上,结合MIPS32 4Kec处理器的结构特点,完成算法的移植工作,并采用精简与汇编相结合的方式对系统进行优化,测试结果表明该系统具有较高的实时性和语音质量.