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程培刚 《电子技术与软件工程》2021,(3):30-31
本文研究地面数字电视广播单频网,分析其系统组成和传输覆盖,对工程实施和优化完善提出建议。地面数字电视广播单频网是我国广播电视体系的重要组成部分。单频网在传输覆盖工程中的应用十分常见,不仅可以提高频率规划效率,还可以解决覆盖盲区问题,提高覆盖率。 相似文献
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本文对地面数字电视覆盖网优化方法进行了研究,介绍了网络优化常用的传统经典优化算法及其在地面数字电视多频网频率指配和单频网优化中的应用,为地面数字电视覆盖网优化提供了技术参考. 相似文献
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本文结合云南省地面数字电视700兆赫兹频率迁移项目的技术验收和单频网调优实践,对地面数字电视发射机的重要指标检测、覆盖效果外场收测和单频网组网测试的简要理论和具体操作进行了阐述,旨在为广播电视技术人员对类似技术系统的测试提供操作参考。 相似文献
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随着广播电视无线数字化覆盖工程实施的逐步深入,地面数字电视频率规划工作已成为各级广播电视管理和技术部门面对的重要课题.本文通过辽宁单频网规划方案的分析介绍,针对规划中遇到的问题展开研究,并提出了解决方法,为其他省市的单频网规划提供了参考. 相似文献
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随着地面数字电视的发展及单频网技术的应用,越来越需要对其信号覆盖质量进行较为精确地评估分析,本文通过研究基于高精度抽样统计算法的数字单频网信号质量测算与分析方法,实现了相应的测算与分析软件,为地面数字电视及CMMB频率规划计算提供技术支持. 相似文献
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提出一种DTMB接收机抗单频网回波干扰性能实验室测试方法.首先,测量系统工作模式下的射频保护率PR、0 dB回波最大延时dmax以及延时超过dmax时回波幅度最小衰减量Dmin,然后根据射频保护率PR定义计算出延时超过dmax时有用信号功率所占回波总功率的百分比.并基于理论六边形单频网模型研究了固定接收和移动接收下DTMB接收机抗单频网回波干扰性能在不同FFT窗口同步方法下对单频网覆盖地点概率估计的影响,仿真结果表明接收机特性对单频网覆盖率有重要影响. 相似文献
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DTMB单频网组网概述 总被引:1,自引:0,他引:1
就地面数字电视国标(DTMB)单频网(SFN)组网的概念、系统构成单频网同步原理、激励器原理以及实验室测试方法等作了系统介绍。同时通过对实际组网中可能遇到的问题以及需注意的事项给出分析和解决办法。 相似文献
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Göran Malmgren 《Wireless Personal Communications》1995,2(4):307-319
A receiver in an ODFM based broadcasting system allows all transmitters in a radio network to simultaneously broadcast the same information in the same frequency block. This procedure generates an artificial multipath environment at the receiver. Since the receiver is designed to overcome these problems, such a Single Frequency Network (SFN) provides good coverage and frequency economy in national applications. However, the efficiency in local SFN has been questioned. The network planning of local SFNs is a mixture of conventional frequency reuse planning and planning to avoid excessive propagation delays caused by the artificial delay spread. In this paper we propose some rules of thumb to be considered in the design of local SFNs. The coverage properties in SFNs are strongly dependent on the transmitter density which determines the degree of diversity of receiving signals from several transmitters. Results indicate that required coverage can be attained in local networks using three OFDM frequency blocks, provided that seven transmitters are used to cover each regional service area. The results also indicate that the duration of the guard interval between two consecutive OFDM signals has to be chosen with some care dependent on the size of the service area. Furthermore, we show that there exists an optimal antenna height for a given coverage area and guard interval. 相似文献
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[摘要]:本文详细论述了移动多媒体广播(CMMB)覆盖网在特定地理环境下的建设思路,针对贵州多山的情况,首次提出了以适当大功率局部单频网建设为主、以简单单点覆盖和补点为辅的省级CMMB规划设计方案。通过贵阳单频网系统的实际试验,验证了上述思路的合理性。该建设方案对多山地区CMMB系统建设具有借鉴意义 相似文献
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All transmitters in a single frequency network (SFN) simultaneously transmit the same information within the same frequency block. Simulcasting provides a diversity gain which has been shown to yield good coverage. In traditional analysis uncorrelated shadow fading is used. In some cases this assumption does not capture the behaviour of the shadow fading, e.g., when several transmitters are shadowed by a large obstacle. We investigate the changes in coverage due to correlation among the received signals field strength from different transmitters. A spatial shadow fading correlation model is proposed and validated using the Blomquist-Ladell (1974) prediction method on a digital terrain data base. Results for both wide area and local SFN show that the coverage properties depends on the correlation in the shadow fading. This will affect the planning process since strong correlation, due to the structure of the terrain, yields better coverage for high transmitter powers (interference limited systems) and worse coverage for low transmitter powers (noise limited systems) 相似文献