The digital dawn in Europe [HDTV]

Europe's digital television plans downplay high-definition applications because of their previous defeat by an uninterested public. Europe's move from analog to digital television is still unfolding. It all began in 1986 with an Europe-wide research project that used digital technology to enhance analog television. Under the umbrella of Project EU-95 manufacturers and broadcasters throughout the region joined forces to develop a high-definition television (HDTV) system native to their part of the world. The European system used 1250 picture lines, exactly twice the 625 lines of the domestic phase alternation line (PAL) system, to make compatibility with existing television sets easier to achieve. But it did not build directly on the PAL standard. Instead, the high-definition system built on a then-new 625 line MAC (multiplexed analog components) and so was called HD-MAC     

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     

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      

The digital backlot [cinema special effects]

Special effects become more special thanks to digital processing at every level of filmmaking. Here, the author describes how Hollywood's nearly insatiable demands for novelty are being met with state-of-the-art graphics technology and innovative craftsmanship     

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     

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。     

The congressional corral [digital media copying prevention]

For now, technologies for ripping, mixing, and burning digital technology are lawful to manufacture and distribute in the United States. But for how much longer? The motion picture industry among other groups of copyright holders, wants Congress to mandate that standard technical protection be installed in all digital media devices. In March 2002, Senator Ernest ("Fritz") Hollings (D-S.C.), with the endorsement of Senator Dianne Feinstein (D-Calif) and others, introduced legislation to do just that. His Consumer Broadband and Digital Television Promotion Act (CB DTPA) would give representatives of technology companies, copyright holders, and consumer groups 12 months to agree on such "standard technical measures". The act would require the Federal Communications Commission (FCC) to conduct a rulemaking that would lead to the requirement that a standard protection measure be embedded in every digital media device. This latter term is broadly enough defined to include general-purpose computers. Making or distributing digital media devices without the standard measure, or removing or altering the measure, would be illegal and, if done for profit, would be a felony.     

Extreme lawsuits [digital copyright]

Copyright owners concerned that digital technology can allow consumers to quickly make perfect copies of their works have increasingly considered adopting technology to limit that capability-technology that often limits viewing or hearing those works as well. The current fights over digital copyright are basically struggles over two questions. One is: how should the law protect copyright owners who control access to their works with measures such as encryption? The other asks whether you should be held liable for copyright violations if you make a product that can evade those control measures-but that also has legitimate uses. Answers to these questions are now emerging, if fitfully and confusingly, from a host of lawsuits, legislation, and business developments. Those answers will have far-reaching effects on everything from how we purchase music, movies, and other cultural works; what we can do with them after we buy them; and how future consumer electronics products are designed.     

Modulation for terrestrial broadcasting of digital HDTV

The digital modulation methods used by the DigiCipher, DSC-HDTV, ADTV, and ATVA-P digital high-definition television (HDTV) systems are discussed. Three of the systems use a quadrature amplitude modulation method and the fourth uses a vestigial sideband modulation method. The channel equalization and spectrum sharing of the digital HDTV systems is discussed     

Source coding for digital HDTV terrestrial broadcasting

It is claimed that an all-digital system will provide true high-definition television quality and coverage area equivalent to NTSC without noise and interference. Less transmission power may be required, and the signal will be easy to encrypt. The proposed source coding algorithms are reviewed, and the methods by which they are used in the proposed digital HDTV terrestrial broadcasting systems are discussed     

Multicarrier modem for digital HDTV terrestrial broadcasting

A digital modulation system using orthogonal frequency division and multiplexing (OFDM) is addressed in this paper. Such a system presents the advantage of coping with echoes more easily than classical single-carrier modems, thanks to the insertion of a guard interval between two symbols. The signal equalization is then achieved in the frequency domain. This OFDM modem is improved by using dual polarizations. In this configuration, it can convey a 70 Mbits/s (HDTV) bit stream in an 8 MHz UHF channel. Some experimental results relate field trials carried out in several countries with such equipment.     

Channel coding for digital HDTV terrestrial broadcasting

In order to transmit the HDTV signal in 6 MHz, the four United States digital HDTV proponents, the DigiCipher, DSC-HDTV, ADTV and ATVA-P systems, are reducing the video data rate of HDTV to 15-17 Mb/s, a compression ratio of approximately 60-70 times. The high compression dictates that channel coding be used to avoid block errors and multiframe error propagation. High efficiency in channel utilization required by the 6-MHz limitation means that the channel must be properly equalized and that the multipath and interfering signals must be severely limited. The channel coding techniques used for error reduction include data interleaving, error detection and replacement, and error correction at different levels of protection for bits and blocks of unequal importance     

Adaptive importance sampling [digital communication]

Parametric adaptive importance sampling (IS) algorithms that adapt the IS density to the system of interest during the course of the simulation are discussed. This approach removes the burden of selecting the IS density from the system designer. The performance of two such algorithms is investigated for both linear and nonlinear systems operating in Gaussian noise. In addition, the algorithms are shown to converge to the optimum improved importance sampling density for the special case of a linear system with Gaussian noise     

Eternal bits [digital files preservation]

The MIT Libraries is addressing the problem of maintaining and sharing digital content over the long haul with a project called DSpace. For this digital repository, a simple, open-source software application was built that not only accepts digital materials and makes them available on the Web but also puts them into a data management regime that helps to preserve them for generations to come. Other organizations worldwide have begun similar efforts including Cornell University, and the University of Toronto, the University of Cambridge. DSpace has a growing group of committed programmers distributed across the globe who continually maintain and improve it.