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主要讨论DVB条件接收的系统组成及系统原理,根据现有小县市广播电视运营机构对收费管理的要求,阐述简易条件接收的系统构成、原理及其特点。 相似文献
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数字电视的条件接收系统原理与应用 总被引:1,自引:0,他引:1
数字电视指将传统的模拟信号转化为数字进行处理、传输和接收的系统。数字电视的条件接收系统运用各种数字技术通过对节目的加扰处理,使只有授权用户才能收看被加扰节目,从而保障运营商的利益,保证数字电视发展。
本文主要闻述当前前数字电视使用的条件接收系统的基本原理,以及实际中应用两种条件接收方式的设计和实现,并比较两种方式的优势和不足。最后介绍当前国内数字电视发展的现状。 相似文献
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数字电视条件接收系统的实现 总被引:1,自引:0,他引:1
数字电视条件接收系统是数字电视加密控制的核心技术保证,实现各项数字电视广播业务的授权管理和接收控制。设计一种适合各中小广播电视运营商开展数字电视广播业务需要的条件接收系统,给出了系统的总体设计和结构。 相似文献
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NVOD(Near Video on Demand,准视频点播)是有线数字电视增值业务的一个重要组成部分,它主要由视频服务器和DVB(Digital Video Broadcasting)前端的其他设备如复用传输系统、条件接收系统、节目制作系统等以及一些终端设备构成。介绍基于有线数字电视的NVOD系统的原理及系统构成,通过一个实例重点介绍NVOD相关的SI信息的生成和接收方法。 相似文献
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条件接收系统密码体系综述 总被引:4,自引:0,他引:4
本文介绍了条件接收系统(CAS)的基本原理和条件接收系统密码体系的组成,并对目前国际上主要的条件接收系统中的密码体系做了分析和比较,最后提出了几项条件接收系统密码体系的发展方向。 相似文献
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针对协作非正交多址(NOMA)系统中信息安全传输问题,该文提出一种基于修改转发(MF)中继的物理层安全(PLS)传输方案。该方案利用MF中继将解码信息修改后再转发,避免了合法信息泄露到窃听节点。首先对NOMA-MF系统进行建模,然后推导了系统安全中断概率(SOP)、严格正保密容量(SPSC)和窃听概率(IP)来衡量系统的保密性和安全性,以及中断概率(OP)以衡量其可靠性。此外,推导了系统的渐近性能,对比分析了解码转发(DF)协议下NOMA-DF系统与NOMA-MF系统的性能。推导及仿真结果表明:NOMA-MF系统的保密性能和安全性能比NOMA-DF系统更具有优势;NOMA-MF系统的OP和IP之间存在最优信噪比(SNR)以实现系统安全及可靠性的平衡;存在最佳功率分配参数以实现最低的SOP和OP。 相似文献
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M. Sh. Levin 《Journal of Communications Technology and Electronics》2013,58(6):584-593
The paper addresses modular design and improvement/extension of the management system in the smart home and the building automation system (BAS). The design procedure is based on the hierarchical morphological multicriteria design (HMMD) approach: (a) construction of a tree-like system model, (b) generation of design alternatives for leaf nodes of the system model, (c) the bottom-up process: (i) selection of design alternatives for system parts/components and (ii) composition of the selected alternatives into a resultant combination. Here, the HMMD approach with interval multiset estimates for design alternatives is used. The system improvement scheme is based on the following: (a) upgrade of the system components (strategy 1), (b) system extension by adding an additional part (strategy 2). The multiple choice problem with interval multiset estimates for improvement operations is used in system improvement procedure. Two basic applied illustrative numerical examples are considered: (1) a modular management system for the smart home and (2) a modular building automation system consisting of four parts. 相似文献
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在无线光通信系统中采用光码分多址(OCDMA)技术,可以充分利用其丰富带宽,提高系统性能。考虑背景光噪声、探测器噪声、多用户干扰和大气闪烁等影响因素,给出了二维无线光码分多址(2D-WOCDMA)系统模型,在该模型中采用了脉冲位置调制(PPM)和光纤布拉格光栅(FBG)编解码器。通过数值分析,详细讨论了该无线光通信系统的性能。结果表明,大气闪烁是影响二维无线光码分多址通信系统性能的重要因素,当其对数方差较大时,系统难以实现通信,需要采用诸如多用户检测、信道编码及阵列接收等技术提高系统的性能;二维无线光码分多址通信系统适合采用1550 nm波段;该通信系统还受背景光、雪崩光电二极管(APD)增益和调制消光比等因素的影响。 相似文献
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In this paper, we propose and analyze a novel multicarrier (MC) multicode (MCD) code-division multiple-access (CDMA) system employing wavelet packets (WPs) for modulation. This system can achieve robust performance against multipath fading due to the localization of WPs in the time and frequency domains. The analytical framework is presented, and the system performance with diversity is evaluated by means of bit error rates and the outage probability . Since WPs have lower sidelobes compared to sinusoidal carriers, our system is very effective in reducing the problem of intercarrier interference. The effects of system parameters (e.g., order of diversity, fading parameters, and WP type) were investigated. The major contribution is to compare the performance of the system to that of the MC/MCD-CDMA system that is based on sinusoidal carriers. The results reveal a considerable performance improvement of our proposed system over the MC/MCD-CDMA system. 相似文献
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改进的传输参考型超宽带系统抗NBI性能 总被引:1,自引:1,他引:0
为研究带有有限长脉冲响应陷波滤波器(NF)的传输参考型超宽带系统(TR-UWB)的抗窄带干扰性能,在IEEE 802.15.3a建议的标准超宽带信道下,分析比较了在不同参数设置下,该系统自相关接收机的误比特性能。仿真结果表明,带有陷波滤波器的传输参考型超宽带系统能够有效降低窄带干扰,并且系统接收机结构简单,无需信道估计,大大降低了计算量和系统复杂度。 相似文献
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Smart Dynamic Resource Allocation Model for Patient-Driven Mobile Medical Information System Using C4.5 Algorithm 下载免费PDF全文
Ching-Kan Lo Hsing-Chung Chen Pei-Yuan Lee Ming-Chou Ku Lidia Ogiela Cheng-Hung Chuang 《电子科技学刊:英文版》2019,17(3):231-241
A mobile medical information system (MMIS) is an integrated application (app) of traditional hospital information systems (HIS) which comprise a picture archiving and communications system (PACS), laboratory information system (LIS), pharmaceutical management information system (PMIS), radiology information system (RIS), and nursing information system (NIS). A dynamic resource allocation table is critical for optimizing the performance to the mobile system, including the doctors, nurses, or other relevant health workers. We have designed a smart dynamic resource allocation model by using the C4.5 algorithm and cumulative distribution for optimizing the weight of resource allocated for the five major attributes in a cooperation communications system. Weka is used in this study. The class of concept is the performance of the app, optimal or suboptimal. Three generations of optimization of the weight in accordance with the optimizing rate are shown. 相似文献
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论文提出了一种基于安全系统工程理论[1]的航空信息系统安全评价指标体系,结合动态控制方法,从战略、技术、管理、工程四个角度评价航空信息系统的安全。首先建立了一个航空信息系统安全评价指标体系,其次采用模糊层次分析法,对系统的静态指标部分进行了安全评估,得到了较好的评估结果。 相似文献
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The DSRC (Dedicated Short Range Communication) system based on the wireless communication technologies is essential to provide ITS (Intelligent Transport Systems) services using the information and communication network which is named Smart Gateway. Focusing on the DSRC system, the RVC (Road-to-Vehicle Communication) system and IVC (Inter-Vehicle Communication) system are studied in this paper. The priority technical issues come out for the purpose of realizing the Smart Gateway using both the DSRC-RVC system and the DSRC-IVC system. 相似文献