Interference to DTTV reception by first adjacent channels

Planning for digital terrestrial television (DTTV) service in a crowded spectrum requires that power limits be placed on all adjacent channels, and in particular on first adjacent channels. Realistic power limits based on intermodulation products generated at the receiver by the desired and undesired signals are proposed. The proposed limits are a function of the fundamental power in the desired and undesired channels and the receiver's 3rd order Intercept Point (IP/sub 3/). The analysis shows that in many markets present Desired/Undesired (D/U) ratios underestimate the expected interference from strong signals, and that the receiver's IP/sub 3/ should be at least 16 dBm for the dynamic range expected in the U.S. Additional improvement can be attained by minimizing the sideband splatter generated by the transmitter of the first adjacent channel and by designing a "smart" front-end receiver.     

地面数字电视频率规划案例研究

1规划的意义。我国的数字地面电视广播（DTTB）标准即将出台。DTTB的频率规划也已摆在议事日程上，并在加紧进行。     

国际电联与欧洲地面数字电视分配规划方法研究

本文介绍了国际电联及欧洲地面数字电视分配规划方法,重点对DVB-T的参考规划配置和参考网络进行了研究探讨,以期对我国的地面数字电视频率规划提供参考。     

国际电联及欧洲地面数字电视规划需求和规划原则研究

地面无线广播电视频率作为稀缺资源,高效合理公平的分配利用一直是国际电联研究的专门课题。国家广电总局广播电视规划院长期参与国际电联相关各研究组的对口研究工作。本文针对国际电联区域性规划会议（ITU RRC-06）以及欧洲地面电视规划组开展的数字地面电视频率规划工作进行分析研究,总结了国际电联会议（含欧洲）频率规划的需求、原则和方法,并对我国开展地面数字电视频率规划工作提出了具体的建议,供业界同仁参考。     

参加AIBD数字地面电视频率规划培训的情况

我于 2 0 0 1年 11月 2 6日～ 12月1日参加了亚太广播发展学院AIBD在泰国曼谷举办的为期 5天的数字地面电视 DVB T频率规划培训。时间虽然很短 ,但信息量很大。培训主要分为两部分内容 :第一部分是由 AIBD的 CART SEN先生讲述数字电视技术的主要特点及与其模拟技术的区别 ,涉及视频信号的数字化、信源编码、多工复用、信道编码及加密、解密过程。内容侧重于DVB T标准 ;第二部分是介绍频率规划的方法和计算工具 ,由德国 L & S公司的 MORGEN先生介绍该公司的频率规划软件。主要内容包括 DVB T的规划参数、干扰分析及对一些数字…     

DTV reception quality field tests for portable outdoor reception in a single frequency network

This paper presents a field measurement campaign developed to study the influence of the special features of a Single Frequency Network (SFN) reception in the C/N thresholds applicable to portable DTV reception. The measurements presented here were performed inside coverage areas of the nationwide SFN which broadcasts DTV (COFDM 8 K mode) services in Spain. The aim of this paper is to present some network planning reference values for portable reception in urban environments where both multipath and multiple transmitter reception have to be taken into account to ensure a good quality of service.     

重庆市地面数字电视覆盖网络建设项目技术规划

本文介绍了重庆市广电发展基本情况,根据重庆自然条件、收视需求和地面数字电视覆盖系统建设需要,做了一系列有针对性的技术测试,提出了重庆市地面数字电视覆盖网络建设项目各系统的技术规划和实施计划。     

Smart, active, and concealable antenna array for portable television reception

This paper describes an array which is concealable with a TV set or set-top box. The array is made of small active antennas which can provide space and polarization diversity by phase switching alone. The array can be manually or automatically controlled to maximize the signal-noise ratio of the desired channel and minimize the interference from undesired channels. The combination of automatically adjustable dual diversity and small physical size makes this device suitable for mobile reception.     

辽宁省地面数字电视单频网频率规划方案分析

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.     

地面数字电视及数字移动多媒体广播发射系统

本文介绍了地面数字电视及数字移动多媒体广播发射系统的基本组成、系统覆盖等相关技术;详细论述了构成发射系统对主要设备-数字电视发射机的技术要求、数字发射机技术的现状、设计理念和采用的新技术,供各级电视台作为模拟电视数字化的参考。     

DTV (COFDM) SFN signal variation field tests in urban environments for portable outdoor reception

The paper presents the measurement results obtained in an extensive field test campaign developed in two large cities of Spain (Madrid and Bilbao) with the aim of characterizing the portable outdoor reception of digital terrestrial television (COFDM - coded orthogonal frequency division multiplexed) and continue the studies carried out by the authors during the past years.     

地面数字电视AVS媒体播放器的开发

本文系统介绍了我国数字音视频编解码技术标准AVS及AVS媒体播放器开发的具体实现流程,该播放器基于多媒体应用开发技术DirectShow体系结构进行开发,在VC＋＋6.0的开发环境下,实现了地面数字电视信号的硬件Dongle获取、解复用、解码和播放。     

地面数字电视传输系统现场性能测试

为客观评估地面数字电视传输系统在不同工作模式下的性能，开展地面数字电视传输系统测试方法和技术的研究非常必要。地面数字电视传输系统测试主要包括实验室性能测试和现场测试两部分，实验室测试只能部分反映系统的传输性能，而现场测试才能更加真实地反映系统实际应用特性。本文将对地面数字电视传输系统现场性能测试的方法和技术进行简单的介绍。     

地面数字电视播出自动监测系统设计

本设计基于AT89S52单片机技术,实现了对数字电视发射与接收情况的自动循环监测与报警.本设计结合了湖南地面数字电视AVS+示范网工程建设和维护经验,针对模拟电视无线数字化后管理的新要求,采取对节目视音频信号并行监测等方法,能够准确进行声光报警.本设计操作简单,功能实用,有着良好的应用和推广价值.     

Planning and operating a fixed radio access network

The case for using radio in the local loop has been well documented, with obvious attractions for both developed and developing countries. Although trial systems of the various technologies exist in many countries throughout the world, operational networks are fewer in number. In June 1996, Ionica launched its service as a public telecommunications operator (PTO) in the UK, using radio in the local loop. This paper describes the experience gained in planning and operating that network. The importance of the access network in maintaining a truly competitive market is discussed. Radio propagation issues are considered, for these play a significant role in the strategic planning of the network, and then in its operational performance. The paper describes the special procedures, and the hardware and software systems, which are required for planning, building and managing the network     

Field measurement based characterization of the wideband urban multipath channel for portable DTV reception in single frequency networks

This paper presents a study developed to obtain several parameters of the small scale fading of the wideband propagation channel applied to the portable and mobile reception of Digital Terrestrial Television (DTV) services in an urban Single Frequency Network (SFN) environment. The study is focused on the calculation of some relevant parameter values related to the multipath behavior of the channel, using field data collected in a real network. Mean values for the Root mean square Delay Spread (RDS) and the frequency domain Level Crossing Rate (LCR) are given, together with an analysis of the influence of the specific environment and network (SFN) features.     

下一代地面数字电视技术发展与应用探索

本文介绍了DVB—T、ATSC、ISDB—T、DTMB四个主要的国际地面数字电视传输标准在全球的应用情况,并对其下一代地面数字电视广播传输标准的技术发展情况进行讨论,同时探讨了未来地面数字电视的应用发展趋势。     

地面数字电视国标DTMB的标准演进与海外推广

地面数字电视国标DTMB自成为国际标准以来,在同类国际技术标准中处于领先地位.在海外多次对比测试中均表现优异,展现出一定的性能优势.本文总结了地面数字电视国标DTMB的演进历程和海外推广情况,重点介绍了老挝地面数字电视全国网项目,为未来DTMB标准在国外推广应用提供借鉴.     

《地面数字电视广播单频网适配器技术要求和测量方法》标准解读

为进一步推动地面数字电视的推广和普及,2008年3月国家广播电影电视总局正式颁布了6项地面数字电视配套行业标准.本文将重点介绍GY/T229.1-200)8<地面数字电视广播单频网适配器技术要求和测量方法>标准,主要内容包括:秒帧初始化包的定义、插入过程以及码速率的适配调整,并对涉及到的相关技术进行细致深入的分析.     

无锡地面数字电视覆盖测试与计算

本文详细介绍了无锡地面数字电视覆盖收测方法，利用收测数据对不同接收方式下的覆盖范围进行理论计算，并进行验证测试。