基于IP over DVB技术的数据分发系统的实现

介绍的数据分发是一种基于IP多播或广播技术的主动服务模式,能广泛应用于局域网、广域网和数字广播网络,其目的是将热点信息推送到海量的用户终端中.提出了基于IP over DVB技术的数据分发系统从发送端到接收端的解决方案,阐述了整个系统的设计思路,发送端与接收端的软件结构及具体实现过程.     

基于OFDM技术的高速有线传输系统软硬件设计

设计了一种基于OFDM技术的高速有线传输系统,分为接收端和发送端两部分,每一部分均由PC、DSP、调制解调模块组成。软件系统由PC端软件和DSP端软件组成,其中PC端软件负责人机交互,DSP端软件主要负责数据的处理和传输,软件设计采用发送端和接收端一体化设计,使用了分层设计和模块化设计的思想,具有良好的复用性和移植性,综合使用了网络开发、DSP、PC编程等技术。系统实验结果表明,该系统能实现数据在双绞线上的高速、可靠传输,拥有良好的应用前景。     

局域网视频广播接收器的设计

描述了一个局域网视频广播接收器的设计。发送端以计算机按UDP/IP的方式向局域网中发送视频广播，在接收端利用FPGA器件设计的接收器对广播进行接收、缓冲、格式转换，以电视作为显示终端，并介绍了在FPGA器件中所设计的各个模块。     

利用DS3接口传输MPEG-2码流

利用PDH/SDH网络传输MPEG-2码流,是数字电视广播的一种解决方案,其关键技术在于发送端和接收端MPEG-2码流与三次群数字码流(DS3流)之间的相互转换.提出码流格式转换中应遵循的一些原则,并给出发送端和接收端的设计思路.     

电视文字广播

电视文字广播(Teletext,以下简称文字广播)是在发送端把文字和图形构成的图象信息,以数码形式插入到全电视信号的场消隐期间的某几行里,用普通电视通道来传送;而在接收端用译码器将发送端送来的编码信号解码、变换为图象信号,显示在电视屏幕上的一种广播业务。它对正常电视广播信号没有什么干扰。在文字广播的数字数据中,除文字、图形信息外,还含有用于信号解调的同步脉冲和控制码。一般地说,文字广播传送的是黑白二     

基于FPGA的实时数字化光纤传输系统

提出一种实时数字化光纤传输系统,该系统分为发送端和接收端。发送端用A/D转换器将输入的模拟信号数字化,再用FPGA对数据进行处理,并通过光纤传输。同时,FPGA还控制A/D转换器的工作。接收端用串行收发器TLK1501对接收数据进行解码处理,还原有效信号。实验表明,该系统实时性好、信号传输误码率低、工作性能稳定、抗干扰性强,系统具有可行性和有效性。     

盲速率判决技术在OFDM系统中的应用

该文借助CDMA系统中的盲速率判决技术解决交织与相位旋转(IPR-OFDM)( IPR:Interleaving and Phase Rotation),系统中接收端恢复交织序号,对接收信号进行检测的问题。IPR-OFDM系统在发送端使用了V 个交织器,接收端为了恢复数据需要知道发送端使用的交织器序号进行解交织。一种解决方法是发送辅助信息(SI:Side Information),这需要占用信道容量;该文借助于CDMA系统中速率判决的思想提出一种在接收端进行盲判的方法,它通过检测CRC(循环冗余校验码)和反转误码率(SER)信息等来获得所需要的交织序号,这种方法相对于前者提高了信道利用率。     

时分复分技术的FPGA实现

用FPGA芯片来实现时分复分接技术,设计复用电路和分接电路。发送端完成复用电路。在发送端将一路1024K数据、一路512K数据、7路64K数据通过时分复用,合成一路2048K数据,传输出去。接收端完成分接电路。在接收端,利用同步技术,从2048K数据中,分解出发送端的原始数据:一路1024K数据、一路512K数据、7路64K数据。经过波形对比验证,分接出来的数据与原始数据一致。     

数据广播中的UCL标引与传输机制

UCL(Uniform Content Locator)是作者、编者和读者进行语义沟通的工具,是数据广播中解决接收端数据信息的快速选择、信息过滤、智能代理和信息的主动服务的基础.本文系统地介绍了数据广播中UCL的概念,提出了在数据广播中进行UCL标引的方法和两级复用方法,研究了数据广播的UCL-W标引方案,研究了多映射与复用技术,最后给出了在数据广播的传输过程中,发送端对数据信息进行采集、标引、映射、复用、格式转换和调制的工作流程.实验验证了理论方案的正确性和有效性.     

部分信道状态信息下多天线系统的最优发送

在实际的单用户多天线平坦衰落通信系统中,接收端往往具有理想的信道状态信息,而发送端只有来自接收端的部分信道状态信息反馈,因此在发送端信道模型假设为复高斯随机矩阵.在发射端具有信道协反差反馈或者均值反馈的情形下,对达到最大的信道容量即信息论角度的最优化问题进行了理论分析,研究了系统的最优发送方案.对目前的关于单方向发射的最优条件进行扩展,进一步推导了沿任意多个方向发送达到信道容量的条件.数值结果验证了分析结论.     

Response Time Analysis in a Data Broadcast System with User Cache

Data broadcast has been considered a promising way of information dissemination to a massive number of users in a wireless communication environment. Reducing user-waiting time is a major problem in developing a data broadcast system. There are two approaches for this problem; One is to design a broadcast schedule at the server side which reduces the mean response time, and the other is to utilize a local cache at the user side which may respond to a user request instantly. Though these two approaches were addressed separately in the literature, they may be taken jointly for better performance. The performance of system with joint approach depends on several factors such as broadcast schedule, cache size, cache management strategy, etc. In this paper we analyze response time in a data broadcast system with joint approach in which information items are structurally related with each other as in WWW. Based on the worst-case assumption, we derive a lower bound on the system performance for a given set of broadcast schedule, cache size, and cache management strategy. This result will be of help for designing and developing a data broadcast system. We support our analysis by carrying out an extensive simulation on some interesting proposed broadcast schedules and cache management strategies.     

信号异常？不要慌张——播出系统外来信号异常的分析与快速恢复

本文通过介绍苏州台播出系统遇到的外来信号的常见异常问题,为电视台内播出一线的技术人员提供一些常用的分析和解决播出外来信号异常问题的方法和经验,以此提高播出人员处理和解决信号异常的能力,保证电视台的安全优质播出工作。     

基带+IP异构高清播控系统建设方案

IP化是电视播控系统必然趋势,但由于习惯了基带架构,我们对于纯IP化的播出安全仍有担心。为此,我们建设了基带+IP异构的高清播控系统。系统上线至今运行稳定,效果良好。     

电视播控系统网络及服务器备份策略

随着科技的进步,电视播控系统网络也在不断发展,但是电视播控系统网络的安全以及做好服务器备份工作不容忽视.国家广电局也颁布了《广播电视播出管理规定》,对维护电视播控系统网络和服务器备份做出了明确规定,提出要对操作系统、服务器配置参数以及其他应用软件进行备份等,注意净化电视播控系统网络.本文将简单针对如何维护电视播控网络安全与做好备份工作提出个人建议,希望能够为网络电视技术提供参考.     

Modeling and analysis of applying adaptive modulation coding in wireless multicast and broadcast systems

Traditional wireless communications only utilize fixed-rate multicast and broadcast. In other words, only the most robust modulation and coding scheme can be applied for data transmission. Such a scheme fails to sufficiently exploit the potential gains of multicast and broadcast, resulting in bandwidth waste. To overcome such a problem, investigating the rate adaptation of multicast and broadcast wireless systems is the primary task. Unlike the traditional wireless systems, this paper presents an analytical model with rate adaptation for both multicast and broadcast. Adaptive modulation and coding are applied to achieve rate adaptation. We construct a stochastic model by using Finite State Markov chains for the multicast broadcast system modeling. The model’s outputs are shown to approximate to the results of our system level simulations. The model derives the performance of rate adaptation in multicast and broadcast. With the deduced modeling results, we can predict the system throughput providing the channel states, and the modulation and coding schemes variations.     

High Performance Data Broadcasting Systems

Data broadcasting as a means of efficient data dissemination is a key technology facilitating ubiquitous computing. For this reason, broadcast scheduling algorithms have received a lot of attention. However, all existing algorithms make the core assumption that the data items to be broadcast are immediately available in the transmitter's queue, ignoring the key role that the disk subsystem and the cache management play in the overall broadcast system performance. With this paper we contribute a comprehensive system's perspective towards the development of high performance broadcast systems, taking into account how broadcast scheduling, disk scheduling, and cache management algorithms affect the overall performance. We contribute novel techniques that ensure an efficient interplay between broadcast scheduling, cache management, and disk scheduling. We study comprehensively the performance of the broadcast server, as it consists of the broadcast scheduling, the disk scheduling, the cache management algorithms, and the transmitter. Our results show that the contributed algorithms yield considerably higher performance. Furthermore, one of our algorithms is shown to enjoy considerably higher performance, under all values of the problem and system parameters. A key contribution is the result that broadcast scheduling algorithms have only a small effect on the overall system performance, which necessitates the definition of different focal points for efforts towards high performance data broadcasting.     

广播电视安全播出指挥调度平台管理系统

安全播出工作是广播电视的生命,随着广播电视和现代科技的发展,广电局的监管能力和应急指挥调度需要更新更便捷的技术系统,来保证安全播出日常管理工作和应急处置工作的顺利进行。从应用前景、发展趋势、主要功能及技术难点、技术关键等方面简要介绍了广播电视安全播出指挥调度平台管理系统。     

在播出实际中数字电视指标测试的意义

数字播出系统在青海电视台更新4年多时间,在播出设备维护中,对数字硬盘播出系统的指标在实际测试和运用中发现,如果单纯地以技术指标作为衡量数字播出中图像质量的标准,存在一定的误区,就此现象有针对性地进行分析和阐述。     

数字播控技术下电视台播出系统的优化设计

针对电视台播控系统在机房建设初期采用的模拟数字播出系统的软件无法适应现代全数字硬盘播出要求,需要对其进行升级优化,以满足全数字化播控要求。因此,阐述电视台数字播控系统构成,分析电视台数字播出系统存在的无法自动搜索、自动复制以及自动编排节目表单等问题,并针对存在的问题进行优化,提高电视播出系统的稳定性和可靠性。     

Cooperative multihop broadcast for wireless networks

We address the minimum-energy broadcast problem under the assumption that nodes beyond the nominal range of a transmitter can collect the energy of unreliably received overheard signals. As a message is forwarded through the network, a node will have multiple opportunities to reliably receive the message by collecting energy during each retransmission. We refer to this cooperative strategy as accumulative broadcast. We seek to employ accumulative broadcast in a large scale loosely synchronized, low-power network. Therefore, we focus on distributed network layer approaches for accumulative broadcast in which loosely synchronized nodes use only local information. To further simplify the system architecture, we assume that nodes forward only reliably decoded messages. Under these assumptions, we formulate the minimum-energy accumulative broadcast problem. We present a solution employing two subproblems. First, we identify the ordering in which nodes should transmit. Second, we determine the optimum power levels for that ordering. While the second subproblem can be solved by means of linear programming, the ordering subproblem is found to be NP-complete. We devise a heuristic algorithm to find a good ordering. Simulation results show the performance of the algorithm to be close to optimum and a significant improvement over the well known BIP algorithm for constructing energy-efficient broadcast trees. We then formulate a distributed version of the accumulative broadcast algorithm that uses only local information at the nodes and has performance close to its centralized counterpart.