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     

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      

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     

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.     

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     

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     

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     

A packet delay analysis for cellular digital packet data

We formulate and analyze a model of voice and data burst traffic for cellular digital packet data (CDPD). To develop a tractible model, we make some reasonable simplifying assumptions to model the voice traffic and one of the logical CDPD channels as an M/M/1 queue in a random environment. Rather than explicitly solve the resulting matrix quadratic equation, we develop an asymptotic analysis that gives us simple approximate formulas (with error bounds) for many performance measures of interest. In particular, one metric that we highlight comes from using our approximate mean data burst delay formula to characterize the performance of a set of interacting logical CDPD channels. We do so by describing it in terms of an equivalent number of independent, dedicated CDPD channels, We can use this metric to suggest what the optimal number of logical CDPD channels for a given system should be     

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     

A robust coding scheme for packet video

Some of the important characteristics and requirements of packet video are discussed. A layered packet video coding algorithm based on a progressive transmission scheme is presented. The algorithm provides good compression and can handle significant packet loss with graceful degradation in the reconstruction sequence. A network simulator used in testing the scheme is introduced, and simulation results for various conditions are presented     

Channel coding scheme for in HDTV digital VCR

The authors have developed an experimental in HDTV digital videocassette recorder (VCR). The VCR can record HDTV digital base-band signals for more than 64 min on a in metal particle (MP) tape. An eight-to-eight modulation ( ) scheme has been developed for this VCR to realize high-density recording. In order to suppress sufficiently the low-frequency components and reduce the occurrence probability of long-run-lengths for the recording data sequence, a new conversion table and bit-rearrangement method have been introduced in this modulation scheme. This conversion table has been particularly structured to reduce run-length using the bit-rearrangement process. Three kinds of typical HDTV images were used to evaluate the performance compared with the scrambled-NRZ method. The run-length distribution and the frequency spectrum were calculated for each image. The results showed that the occurrence probability of long-run-lengths were well reduced and the low-frequency components along with the DC component were sufficiently suppressed. Cross-talk interferences and overwriting noises were also found to be much less than those for the scrambled-NRZ method.     

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     

Signal processing for a digital HDTV chromakey mixer

The quality requirements on HDTV are much higher compared to standard TV. For this reason sophisticated methods of signal processing are necessary within the HDTV studio. This paper compares different methods of key signal generation with respect to the resulting picture quality. Furthermore, an automatic set-up procedure for a digital chromakey mixer is described.     

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     

Optical digital transmission of HDTV signals for `contribution' use

The key technologies for a 1.2 Gb/s HDTV optical digital transmission system for contribution service use are addressed. A wide-dynamic-range optical receiver is described. Attained average received optical power for an error rate of 10^-9 was from -6 dBm to -38 dBm, with an optical dynamic range of 32 dB. This system provides for transmission lengths from a few meters to up to 80 km. It was confirmed that the system developed is available for interconnecting HDTV equipment within a studio and for dispatching HDTV programs from a production site to a postproduction studio. Scrambled-8B1C NRZ line coding was used to keep clock recovery reliable in the receiver. The line-coding circuit satisfies the BSI (bit sequence independent) property and can be easily implemented using commercial high speed ECL devices     

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。     

高清晰度数字电视(HDTV)与个人电脑技术的融合

论述了个人电脑系统及计算机网络在HDTV技术发展中的地位和作用，从设计水平上分析了个人电脑处理播放HDTV节目的技术基础，提出了未来数字电视网络与计算机网络融合为一、个人电脑与电视合二为一的观点。