数字卫星电视接收应用方案

随着广播电视事业的蓬勃发展,我国卫星电视节目的上星传送方式已由传统的模拟方式积极过渡到数字压缩传送方式。以中央电视台、中国教育电视台以及省级电视台卫星节目共40余个频道的现状看,各个频道目前已经基本上应用了数字压缩技术。中央电视台第一套节目也将于2005年底停止模拟信号的发送。鉴于这一喜人的变化,对于一些目前还没有采取应变措施的区、县级有线电视台和镇级广电站,以     

数字卫星电视节目的接收

１绪言目前我国大部分省（直辖市、自治区）都采用数字压缩技术传送卫星电视节目,其中新疆３套、内蒙２套为ＭＣＰＣ方式,其余均用ＳＣＰＣ方式。另外还有中央数套卫星电视节目也采用数字压缩技术传送（表１列出中央及部分省市区数字卫星广播电视接收参数）。全国纷纷采用数字压缩技术传送卫星电视节目后,接收天线口径比收模拟卫星电视大大缩小,图像声音质量明显提高。各地有线台纷纷接收数字卫星电视节目作为信号源。因此掌握数字卫星节目的接收技术就显得十分必要和迫切。下文以在福州接收亚洲２号上的福建卫视东南台节目为例,介绍如…     

数字卫星电视节目接收

随着广播卫星技术的发展,尤其是数字压缩技术的发展,上星节目越来越多,丰富了人们的文化生活。笔者遇到过许多卫视发烧友,在安装、调试天线的过程中走了不少弯路,费了不少劲。下面我就卫星电视节目接收中提一点建议,供广大同仁参考,如有不妥请批评指正。     

CATV系统中数字卫星电视节目的接收

近年来,由于数字压缩技术的突破,使电视图像、声音以及各种多媒体信息都采用数字方式来处理。过去,卫星电视转发器的常规使用方法是一路模拟电视信号一般占用一个转发器带宽。采用数字压缩技术后,在一个转发器带宽内可传送多套数字电视节目。采用数字电视后不仅大大提高卫星电视图像质量,而且可以减少地面接收天线口径。目前我国大部分省、市及中央台都采用数字压缩技术传     

数字卫星电视接收系统故障分析

数字卫星电视接收系统的组成与模拟卫星电视系统类似,也是由卫星信号接收天线、馈源及下变频组件LNB、线路放大器（天线距离解码器较远时需要）、卫星电视接收机（对于数字卫星电视又称数字卫星电视解码器）以及监视器等终端设备组成。但是数字卫星电视接收系统具有自己的特殊性质,例如同是C波段,数字卫星电视信号强度较模拟卫星电视信号小,并且一个数字卫星电视频道可以同时传送多路数字卫星电视。对于数字卫星接收系统,系统故障有其本身的特点;加上许多数字卫星电视接收设备没有配电路图纸,检修起来很不方便。笔者依自己安装、维…     

浅析数字卫星电视接收天线

卫星电视接收天线就是安装有线电视前端机房外面空地或楼顶上,类似“大锅盖”状的设备。天线的作用是将来自地球同步卫星上的携带有数字电视信号的电磁波接收下来,通过反射将其聚焦于抛物面状天线的焦点上,进而传输给馈源。本文就卫星电视接收天线的种类、特点以及安装工作进行探讨。     

数字卫星电视接收的实践

随着广播电视技术的发展，数字技术在广播电视中的应用越来越广泛，数字卫星电视以其抗干扰性强、使用带宽小、图像质量佳的特性。从而推动了数字卫星电视的发展，使整个模拟卫星电视逐渐淘汰。本文试从理论和实践两方面来说明数字卫星电视接收的特点。     

数字卫星电视接收系统故障检修思路

卫星广播电视接收系统由天线、高频头、数字卫星接收机和电视机或监视器等部分构成。在卫星广播电视接收系统安装调试完毕投入使用后，系统通常处于良好的运行状态。由于种种原因也会出现如马赛克、伴音间断、短时图像消失等故障。为使维修人员在卫星电视接收系统发生故障时，能够迅速判断故障部位和故障类型从而进行检修，本人根据卫星数字电视接收系统的特点及实践经验，提出几条与检修有关的思路，仅供同行参考。     

数字卫星电视解码器PID设置

在接收数字卫星电视节目时 ,往往需要对要接收节目的参数进行设置。对于大多数的通用数字卫星解码器 ,一般只需要设定ＬＮＢ参数 (包括接收频率、本振频率、极化方式 )、数字信号传输符码率、ＦＥＣ ,然后通过自动搜索就可找到要收的节目。有些专业数字卫星的设置比较复杂 ,除了要设置一般解码器的参数之外 ,还必须对接收卫星节目的ＰＩＤ参数进行设置。对于单频多套节目的卫星信号 ,各个节目的区别只是在于ＰＩＤ的不同 ,要接收一定的节目就必须设定其节目的ＰＩＤ。对于电视台等专业节目部门 ,一部解码器长期固定接收某一个节目 ,要求的是…     

Coded channels. Digital television by satellite

Digital compression techniques will allow satellite TV broadcasting to continue to compete effectively with broadband cable. Instead of transmitting a continuously varying analogue electrical voltage to represent the picture, digital television converts each of the pixels that makes up a TV picture into a coded message. Provided that a receiver can decode the digital message, it can build up a completely new picture, dot by dot, on the screen, with perfect results. As digital compression of television signals becomes the norm, and broadcasters try to squeeze ten or more, services down the same bandwidth that used to carry just one analogue picture, lessons will be learned-about what is acceptable on different types of picture material. Variable rates of compression could perhaps be applied to different scenes in real time, and the channel bandwidth provided for each programme being transmitted over a satellite transponder could be varied dynamically according to the data rate that each scene requires. The author discusses these various aspects of data compression and channel coding     

Digital data transmission over nonlinear satellite channels

The M-ary PSK system over nonlinear satellite channels, in the presence of an arbitrary number of interferers and additive Gaussian noise on the uplink and downlink paths, is investigated. The effect of intersymbol interference due to the transmitter filter is also included. The bit error probabilities are obtained using the Gauss quadrature formula and a two-dimensional moment technique     

浅谈数字化电视

数字电视是从电视节目制作、播出、传输到用户接收及系统运行管理全部采用数字编码与数字传输技术的新一代电视技术。数字电视技术是下一阶段电视发展的必然方向,也是当前广播电视科技发展的制高点。     

Digital television

It is now recognized worldwide that all television services, including HDTV, will eventually become digital, but there is wide disagreement about the optimum timing for transforming existing analog systems. A major driving force is the ongoing partial merging of television and digital computers in interactive multimedia services involving digital television and applications in areas like information (news), education, medical, entertainment, etc. A major target is to maximize interoperability of video services at all levels, including various resolutions, different transmission and storage mechanisms, as well as bit rates. This paper provides an overview of the current status in digital television, techniques used, future prospects, and research areas that need to be investigated. The maturity of compression techniques needed for digital video storage and transmission, and the establishment of international standards for digital television representation, like MPEG-2, have greatly contributed in this transformation. Recent developments are mentioned, including the American “Grand Alliance” FCC effort for digital terrestrial HDTV broadcasting, and also other efforts for digital television by cable and DBS. The concept of hierarchical multiresolution coding is also explained, and some of its techniques are briefly described     

浅谈卫星电视干扰的几种解决方案

抚州市位于江西省东部,全市土地总面积188万平方公里,人口420万．现辖临川区和南城、南丰、黎川、崇仁、乐安、宜黄、金溪、资溪、广昌、东乡10个县。在边远的县城,大部分群众选择用卫星电视接收器来接受电视节目。近些年,由于经济利益的驱使和不正当的竞争,部分农村电视传输经营者对用卫星电视接收器用户进行恶意干扰,导致广大人民群众不能正常收听和收看电视节目。     

广播电视卫星传输（连载五）

5.地球站天馈线系统的播出维护 5.1 机械维护 （1）为防止因生锈造成反射蘿过大及其它性能下降，天馈线系统波导内部必需保持干燥 ，因此应随时检查充气机内的硅胶干燥剂，发现其变红应及时更换。     

Digital television terrestrial broadcasting

Digital transmission will change the way television channels are allocated and will force broadcasters to master a new set of parameters for optimizing service coverage. This article discusses modulation and channel coding issues related to digital television terrestrial broadcasting (DTTB), such as data throughput, spectrum efficiency, single- and multicarrier modulations, interferences under simulcasting conditions, multilayer services, and DTTB coverage. Current advanced television (ATV) research for terrestrial broadcasting in the VHF/UHF bands is converging toward a fully digital implementation. In a digital ATV system, the digitized high definition video sources, with raw bit rate of up to l-Gb/s, are compressed using source coding techniques based on the discrete cosine transform (DCT) coding. The output data rate of the video source encoder, with present technology, is typically 15 to 20 Mb/s. This data rate is sufficient to provide a satisfactory distribution quality video service     

An integrated FEC coding scheme for ATM transmission over regenerative satellite networks

The application of asynchronous transfer mode (ATM) on both wireless and satellite networks requires system adaptation. This adaptation has to improve the overall system's performance, and achieve high quality‐of‐service classes approaching that for fibre‐optic communications. In this paper, a new integrated forward‐error‐correction (FEC) coding scheme is introduced for ATM transmission over regenerative satellite networks. The proposed FEC scheme is a concatenation of two Reed–Solomon codes tailored for the header and payload parts of the ATM cell. This integrated coding scheme is shown to significantly improve the cell loss ratio as compared to the standard CRC code used in the ATM cell header. We obtain both upper and lower performance bounds for the concatenated code and check their accuracy when compared to exact system's performance. Both analytical and simulation results show that a cell loss ratio and bit‐error rate (BER) of 10^?25 and 10^?7 can be, respectively, achieved with minimum delay requirements on the SATCOM link. Finally, an approximation for the system's throughout is obtained. It is shown that using a hybrid selective‐repeat automatic‐repeat‐request (SR‐ARQ) with the RS code, a large throughput of approximately 0.843 can be achieved at BERs lower than 10^?7 for data services. Copyright © 2005 John Wiley & Sons, Ltd.