基于HFC有线电视网络的远程居家看护系统

采用计算机平台和无计算机平台的设计方法 ,整合国际互联网络资源 ,提出以缆线调制解调器进行视频、声音及生理信号的传送 ,以浏览器为界面进行远程居家看护服务。使用传统有线电视播送方式传送视频及声音 ,配合所提出的生理信号传送电路 ,从而整合成远程居家看护系统     

石家庄电视台非线性编辑网络系统设计

随着数字技术和计算机技术的发展,数字化设备凭借其高清晰度、高分辨率等优势,正迅速进入电视领域.为适应电视技术的飞速发展,全面提高电视节目质量及节目制作效率,石家庄电视台适时对制作设备进行改型,购置了非线性后期制作网络系统和虚拟演播室系统,建成了一整套适合本台实际制作情况且独具特色的电视节目生产线.     

电视信号在省网内的传输与维护

DWDM技术允许各载波信道在一条光纤内同时传输,充分利用光纤的带宽,可直接接入多种业务,基于DWDM的SDH传输平台已成为骨干传输的主流,在此平台上,一部分带宽用来传输广播电视节目,另一部分用来直接传输用户数据等,介绍广播电视信号在省网传输中的常见故障及解决办法。     

电视信号在省网内的传输与维护

DWDM技术允许各载波信道在一条光纤内同时传输，充分利用光纤的带宽，可直接接入多种业务，基于DWDM的SDH传输平台已成为骨干传输的主流，在此平台上，一部分带宽用来传输广播电视节目，另一部分用来直接传输用户数据等，介绍广播电视信号在省网传输中的常见故障及解决办法。     

浅析AVS+技术在数字卫星广播中的应用

四川广播电视台拟将四川综合频道（卫视）高清节目上星覆盖全国,拟采用将四川综合频道（卫视）高清信号通过中广网异地传输至上海广播电视台进行加密,同时为了推动AVS+技术在广播电视领域的应用,上海广播电视卫星地球站拟将东方卫视高清、四川综合频道（卫视）高清频道和纪实高清以MCPC方式,通过上海卫星地球站上行系统进行上星传输。     

Visual C++中利用TGA文件实现透明图像

真彩图像文件格式(TGA-Targa)文件是一种带有alpha通道的图像存储格式,广泛应用于专业的图像处理设备和电视编辑设备中.TGA文件的格式中有一个独立于RGB通道的alpha通道,利用该通道可以调节整个图像的透明度.文中重点分析了TGA文件的结构,阐述了alpha通道的工作原理,提供了通过透明图像实现图像叠加的一种方法,最后,给出了使用Visual C 实现图像叠加的一个实例.     

保障演播室直播的安全策略

结合太原电视台新闻频道用于新闻直播的演播室系统的实际应用情况,分别从系统的设计（包括视频、音频、灯光、电源、计算机等）和使用的角度阐述了有效提高演播室直播安全系数的经验和体会。     

Novel synchronization for TDS-OFDM-based digital television terrestrial broadcast systems

As an effective technique for combating multipath fading and for high-bit-rate transmission over wireless channels, orthogonal frequency-division multiplexing (OFDM) is extensively used in modern digital television terrestrial broadcasting (DTTB) systems to support high performance bandwidth-efficient multimedia services. In this paper, novel synchronization schemes, including timing, frequency offset estimation, and phase error tracking, are proposed for the time domain synchronous OFDM (TDS-OFDM) based DTTB systems. Simulations under different channel situations verify the efficiency of the proposed schemes.     

Cutoff rate and outage probability performance comparisons between DVB-T and DMB-T systems under mobile multipath channels

As an effective technique for combating multipath fading and for high-bit-rate transmission over wireless channels, orthogonal frequency-division multiplexing (OFDM) is extensively used in modern terrestrial digital television broadcasting systems to support high performance bandwidth-efficient multimedia services. Cutoff rate and outage probability are two important criteria to evaluate the performance of a practical communication system in radio engineering. In this paper, the cutoff rate and outage probability performance are compared between two important terrestrial digital television broadcasting systems, the cyclic prefix OFDM based DVB-T system and the time domain synchronous OFDM based DMB-T system, under different mobile multipath channel conditions. The DVB-T system and the DMB-T system are summarily introduced. The cutoff rate and outage probability expressions are developed, and simulation results are given for both the DVB-T system and the DMB-T system.     

Source coding, channel coding and modulation techniques used in theDigiCipher system

The DigiCipher high-definition television (HDTV) system, an all-digital approach that achieves full HDTV performance with error-free reception in a single 6-MHz television channel is described. The DigiCipher HDTV system is based on discrete cosine transform coding and uses motion prediction techniques to eliminate redundancy in the digital signal, channel equalization to defeat multipath, and error correction to defeat noise and interference. The source signal, source coding, channel coding, modulation, and performance of the system are discussed     

Channel characterization and television field strength measurements

The new standard in North America for the advanced television (ATV) transmission system will be selected in 1996. The new ATV system is expected to co-exist with the conventional NTSC television system for many years to come. Simulcasting of the two systems will require a good understanding of the channels used. In this paper, a method to characterize a channel using the ghost canceling reference (GCR) signal is presented as well as the method used to conduct field strength measurements of television channels. The channel characterization gives us the time and frequency response of channels. The field strength measurements show the power variation of the signals that are transmitted through a channel over a period of time. The results obtained from field tests for a number of channels and with different polarization of transmitter's and receiver's antennas are then presented. The results for the channel characterization of a cable network using the GCR signal are also presented     

中国公共电视频道现状分析及新媒体时代的发展之道

公共频道是我国特有的产物,是一个政策性的频道,也是广播电视改革的一项重要举措。我国的公共频道目前存在的问题主要包括:公共概念游离、节目生产能力薄弱、缺少完善的评估机制;资金来源单一等。进入新媒体时代,我国公共电视发展既要借鉴西方公共电视的长处、优势,又要结合我国国情,来进一步明确市场定位,增强节目资源的生产与整合能力,健全公共电视评估机制,促进传媒经营收入的多元化,走出一条有中国特色的发展道路。     

Market Competition, Station Ownership, and Local Public Affairs Programming on Broadcast Television

This study examines the relationship between competitive conditions in television markets, ownership characteristics, and commercial broadcast television station provision of local public affairs programming. The results from an analysis of a random sample of 285 full-power television stations showed that half of the stations in the sample did not air any local public affairs programming during the 2-week sample period. Among the study's other findings are that competitive conditions and station financial resources do not necessarily increase the provision of local public affairs programming and that ownership characteristics bear little meaningful relationship to local public affairs programming provision.     

基于EPON的网络电视传输系统的频道切换

提出基于EPON的网络电视传输系统的频道切换机制,给出了利用IGMP snooping组播技术在EPON系统中实现网络电视频道切换的方法与步骤.     

Television Dramas and Support for Controversial Public Policies: Effects and Mechanisms

In this experiment, we examine effects of television dramas on support for controversial public policies (gay marriage and the death penalty) and explore mechanisms that may explain such effects. The dramas influenced support for death penalty but not gay marriage. As predicted, exposure to the relevant drama eliminated the relationship between prior ideology (conceptualized as a continuous variable) and death penalty support. Moreover, the valence of the relationship between prior (increasingly liberal) ideology and salience of a relevant value (perceived importance of a safe and crime-free society) went from negative in the comparison condition to positive after exposure to the relevant drama. These and other results suggest that a television narrative can influence policy support by reframing the dramatic situation to reduce the effect of prior ideology and values and by minimizing processing of the story as intentionally persuasive discourse.     

一套简单经济的加扰方案

目前的加扰方法多采用成品加扰设备，一个节目必须采用一路加扰设备，这样总造价非常高，为此，介绍一种简单经济的U波段节目加扰方法，可解决没有增补频道的老式电视机接收部分增补频道的问题。     

Effects of Carrier Frequency Offset and Channel Estimation Errors on the Performance of MIMO-OFDM Systems in Spatially Correlated Channels

As an effective technique for combating multipath fading and for high-bit-rate transmission over wireless channels, orthogonal frequency division multiplexing (OFDM) is extensively used in high-rate wireless communication systems, such as, the wireless local area network (WLAN) and the digital television terrestrial broadcasting (DTTB) systems, to support high performance bandwidth-efficient multimedia services. Multiple antennas and transmit or receive diversity, multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM), can be used to improve error performance and capacity of wireless systems. In this paper, we consider the effects of carrier frequency offset and channel estimation errors on the performance of MIMO-OFDM systems in spatially correlated channels. Theoretical calculations and computer simulations are done to analyze the performance degradation of MIMO-OFDM systems in spatially correlated channels due to carrier frequency offset and channel estimation errors, and the theoretical and simulated results match well.     

Modeling of the Coding Gain of Joint Coding for Multi-Program Video Transmission

In digital multi-program video transmission, several video programs are compressed (e.g., using MPEG-2), multiplexed, and transmitted over a constant bit rate (CBR) channel. Joint coding, or statistical multiplexing, which is now widely used in digital television broadcasting, dynamically allocates the available channel capacity among programs according to picture content. This scheme is much more efficient than independent coding where each channel is allocated a fixed bit rate. In this paper, we present a model which can relate the decoded picture quality to bit rate, for both independent and joint coding. The model takes into account statistical variations of video program complexity, and incorporates experimental data drawn from formal subjective picture quality assessments. We use the model to calculate the coding gain of joint coding relative to independent coding, in terms of bandwidth savings.     

贵州电视台节目播出中的音频处理

讨论了在电视台播出中出现的不同频道、不同节目之间声音强度差别大的原因,介绍了从模拟到数字的各种音频电平单位、各标准组织的校准电平标准,提出一种在节目播出中应用压限器作音频处理的方法。     

Blind decision feedback equalization for terrestrial televisionreceivers

In December 1996 the Federal Communications Commission (FCC) adopted the Grand Alliance (GA) system as the digital television broadcasting standard for the United States ending a seven-year-long search for a fully digital television standard. MPEG-2 was chosen as the video compression standard, and trellis-coded 8-vestigial sideband (VSB) with a training sequence was chosen as the transmission standard. The laboratory tests that were performed on the final two competing systems, 8-VSB with training sequence and 32-quadrature amplitude modulation (QAM) with blind equalization, showed a need for blind equalization in dynamic channels that could not be adequately handled by an equalizer training on the training sequence alone. Hence, the final GA system recommended the use of blind equalization in the receiver. In this paper, we describe the U.S. digital television transmission standard as it pertains to the equalization problem, typical transmission channel characteristics and the need for blind equalization in terrestrial television receivers