Multiresolution broadcast for digital HDTV using jointsource/channel coding

The use of multiresolution (MR) joint source-channel coding in the context of digital terrestrial broadcasting of high-definition television (HDTV) is shown to be an efficient alternative to single-resolution techniques, which suffer from a sharp threshold effect in the fringes of the broadcast area. It is shown how matched multiresolution source and channel coding can provide a stepwise graceful degradation and improve the behavior, in terms of coverage and robustness of the transmission scheme, over systems not specifically designed for broadcast situations. The alternative available for multiresolution transmission through embedded modulation and error correction codes are examined. It is also shown how multiresolution trellis-coded modulation (TCM) can be used to increase coverage range. Coding results and simulations of noisy transmission are presented, and tradeoffs are discussed     

四通道调频广播数字调制电路

为了覆盖无线广播信号的接收盲点,设计了一种微型化的四通道调频广播补点覆盖设备。其中的调制电路选用FPGA作为核心器件,采用小数分频的数字调频调制技术,把数字传输的广播声音电压信号直接变换成中频信号。这种调制电路不仅非常简单,而且从根本上解决了传统多通道模拟调制器的串音问题。     

Choosing an American digital HDTV terrestrial broadcasting system

A public process has been in place in the United States for six years to establish an HDTV terrestrial broadcasting standard. The process, having moved through a planning phase, a competition phase, and an examination phase, has now entered a cooperation phase. Remarkable progress has been made-a testament to the process. During 1994 the American digital HDTV terrestrial broadcasting system will be tested, fully documented, and recommended to the FCC for adoption     

Advanced digital HDTV transmission system for terrestrial videosimulcasting

Transmission aspects of the advanced digital high definition television (AD-HDTV) system, for terrestrial simulcast delivery of HDTV are described. In AD-HDTV, two quadrature-amplitude-modulated (QAM) carriers, with different power spectral densities, are employed in a frequency division multiplex (FDM) mode within the standard 6-MHz channel. The resulting spectral shaping allows a larger power to be transmitted, compared to that for a single QAM carrier, for the same level of perceptual interference into cochannel NTSC. The coded video data are split into high-priority (HP) data and standard-priority (SP) data, and the vital information is sent on the appropriate QAM carrier, resulting in a robust audio and video transmission system. The availability is higher in scenarios where the carrier-to-noise ratio (CNR) is above the threshold for HP reception but below the threshold for SP reception; this is important in fringe areas. The NTSC planning factors, suitably modified for HDTV delivery, are used to estimate the coverage area for AD-HDTV. The calculated AD-HDTV coverage area of 54.5 miles is comparable to that for NTSC transmission     

Professional HDTV digital recorder

Some of the essential technology for record/playback systems in professional HDTV digital recorders is described. The full bandwidths of 1125/60 HDTV signals (30 MHz for luminance and 15 MHz each for the two color difference signals) were recorded. An 8-8 mapping channel code and integrated detection were used. A special phase locked loop (PLL) to cope with picture search functions was developed. At the high data rate of 148.5 Mb/s per channel and the high linear density of 0.345 μm per bit, the recorder operates with a word error rate of less than 10^-4      

Using object multiplex technique in data broadcast on digital CATV channel

Data broadcast is a new kind of value-add service of DTV broadcasting and some data broadcast protocols have already been established. However, these protocols only describe the method for locating files in data streams, and a method for distribution of a large collection of files in one or more data streams is not provided. Research on this problem mainly focuses on how to decrease the wait time and some methods of allocating files on multiple streams based on access probability are proposed, but how to assign the file with a reasonable bandwidth is ignored. In this paper, we introduced an object multiplex algorithm to optimize the allocation of objects on a DTV channel. This method assigns different bandwidth statistically to a different object according to its size and access probability. In this method, both download time and wait time are considered. It adopts a modified virtual clock (VC) scheduling algorithm to multiplex files accurately and smoothly.     

基于数字播控技术的电视台播出系统优化研究

伴随着我国现代化社会的深化发展,科技的飞速进步,越来越多的家庭中都拥有了数字电视,数字播控技术在之后的时间里,一定是向着创新和标准的方向前进。目前,我国在数字播控技术上的钻研还在逐渐深化当中,本文将针对数字播控技术基础上的电视台播出系统进行优化研究,以期为电视台节目的播出可靠性带来有效的参考价值。     

Integrated alerting and system broadcast channel for a wirelessaccess system

A protocol is described which allows a wireless access system to dynamically multiplex the alerting, system information, and priority access request subchannels on its system-wide broadcast channel. These subchannels each have different requirements with respect to the message length and position within the framing structure; the described protocol meets each of their requirements. The protocol efficiently accommodates a wide range of alerting traffic levels and provides for efficient downloading of system information to subscriber units by using excess capacity when alerting traffic is low. It provides error detection capabilities above that provided by the radio channel alone and is easily extendible to accommodate other services such as paging and low bandwidth broadcast messaging. The flexibility provided by this protocol could permit a broad range of network architectures for wireless access     

Hierarchical NTSC compatible HDTV system architecture — A North American perspective

High definition television (HDTV) has become a major world-wide event in the television arena. Since the early 1980s, when HDTV was first demonstrated by Japan, a number of alternative systems have emerged. These systems clearly reflect the business and political objectives of the particular countries or organizations. In North America, which is the largest single consumer market in the world, technical, business and political considerations are shaping the evolution of HDTV. This paper describes a possible advanced television (ATV) architecture for North America and defines its functional modules and corresponding interfaces. The developed model is recommended as a design tool for standardizing ATV in North America and analysing interrelationships of the functional modules on the economic basis. The paper proposes an ‘hierarchical’ ATV emission system with full NTSC compatibility and HDTV quality. Solutions are recommended for terrestrial broadcast, CATV and satellite. This work describes a total systems approach to HDTV called HDS-NA (high definition system for North America). The two emission signals of HDS-NA: HDMAC-60 and HDNTSC are characterized. RF alternatives for the terrestrial broadcast of HDTV are also discussed.     

The challenges of digital HDTV

The characteristics of digital high-definition television (HDTV) and its advantages over analog and hybrid systems are described. The issues to be addressed in using digital transmission in the terrestrial broadcast environment are examined. Four proposed digital HDTV systems are discussed, and their similarities and differences are highlighted. Key techniques are the use of complex compression coding and motion compensation algorithms     

Source coding, channel coding and modulation techniques used in thedigital spectrum-compatible HDTV system

The digital spectrum-compatible high-definition television (DSC-HDTV) system, a digital HDTV simulcast system designed for United States terrestrial broadcasting on currently unassignable channels, is described. The system uses progressively scanned source signals and is characterized by an effective, high-performance video compression system. Compression includes motion compensation with hierarchical block matching and block transform coding with adaptive quantization according to perceptual criteria. Video compression is designed to simplify the receiver decoding; only a few VLSI chips and only one full frame memory are required. The source signal, source coding, channel coding, modulation, and performance of the system are discussed     

HDMAC coding for MAC compatible broadcasting of HDTV signals

The authors consider the problem of bandwidth reduction needed to allow HDTV (high-definition television) signals to be transmitted through the narrow DBS (direct broadcast by satellite) channel and to simultaneously fulfil the compatibility requirement with the European DBS transmission standard, the MAC/packet family. This problem is studied in the context of the EUREKA 95 project. The HDMAC coding system is outlined; it is a three-mode system (stationary 80 ms, tracking 40 ms, and dynamic 20 ms modes) with motion compensation used in the 40 ms mode. The system was built in hardware and has been demonstrated     

基于DVB-C有线数字电视平台的应急广播系统

介绍了基于DVB-C有线数字电视平台的应急广播系统,依托现有有线数字电视播控与传输平台,应急广播指令与音频信号复用到数字电视播控平台.利用有线电视共缆传输,终端设备的技术实现与数字电视机顶盒基本一致.以全新的理念全面实现了音频/文字信息数字化、播控自动化、管理智能化、扩展自由化,与现有HFC网络完全融合,是广电运营商建设应急广播系统的理想的解决方案.     

HDTV and the new digital television

Introduces a special section of IEEE Spectrum on HDTV and digital television. Mention is made of historical aspects first before a very brief run-down of the papers in the section     

HDTV evolves for the digital era

HDTV was created in an era of analog TV, seeking higher performance through the enhancements feasible in such an environment, such as higher resolution. The digital era is now in place, bringing compression and other processing enhancements, along with a new order of requirements, possibilities, and constraints for TV systems. HDTV in this era has a new meaning, with very different criteria being established. The paper traces the development of HDTV and details current work to establish HDTV systems appropriate for evolving and future digital application     

Compatible coding of digital interlaced HDTV

A compatible coding scheme for interlaced HDTV (high-definition television) is proposed. This scheme provides a standard definition signal and a second channel containing the additional information required to reach the HD resolution. The global scheme is of the pyramidal type: the standard TV is obtained by downsampling the HDTV signal by means of a field-based operation. The standard TV signal is coded, decoded, and upsampled. It is used as a prediction of the HD signal and the prediction error is coded in a second channel. In both branches, motion-compensated hybrid DCT coding is used. In addition, the DCT is taken within the frame     

十堰电视台六个标清频道全硬盘播出系统

本文介绍了十堰电视台六个标清频道全硬盘播出系统的组成及功能,详解了视频服务器、数据库服务器、MDC服务器兼同步迁移服务器、控制工作站、上载工作站、摆渡系统、时钟和同步系统等关键技术。     

浅谈数字HDTV技术

本文介绍了HDTV的基本概念、关键技术与标准、HDTV系统结构等内容。