Digital TV Services Research Articles

Indoor DTV Reception: Measurement Techniques

This paper explores the techniques for measuring DTV signals received in an indoor environment at UHF. It is found that the mean and standard deviation of the received signals are dependent on spatial sampling interval and the number of samples. A minimum spacing of 0.2/spl lambda/ and a minimum number of 100 samples over a minimum length of 20/spl lambda/ are required for more accurate and meaningful conclusions. A 0.5/spl lambda/ window is recommended to compute the running mean. As no other precise measurements are available elsewhere for the UHF band, these results will be useful for planning of future fixed digital TV services.

Home server for home digital service environments

This paper proposes a new scheme of the home server platform for providing home digital services by connecting home networks and the Internet. The proposed scheme is an integrated form of a home multimedia server, a home control server, and a home information server. The proposed system has an interface between access networks and home networks, various kinds of wired and wireless home networks devices, and multimedia processing modules. As examples of home digital services, the system provides a digital TV service, a remote multimedia service, and an instant message service based on the open service gateway initiative (OSGi) framework. We have implemented the proposed home server scheme, and verify that the system can be a core device of the home digital service environments.

Multimedia data processing elements for digital TV and multimedia services in home server platform

This paper describes the design and implementation of multimedia data processing elements for a home server platform. Generally, a home server can be considered as an integrated form of a multimedia data server, home control server, and home information server. As a multimedia data server, the proposed scheme has a digital TV receiver module and a multimedia codec module. Thus, watching digital TV and remote multimedia services are available in this platform. In addition, an error resilient scheme using digital watermarking is implemented to correct transmission errors in a noisy channel.

DVB-RCT: A New Standard for Interactive TV

Interactive digital TV services are now considered the key element to introduce digital TV services and to encourage customers to invest in new digital TV appliances. Some time ago, the Digital Video Broadcasting (DVB) forum, which already produced a harmonized family of technical standards including return channels using telecom networks technologies (PSTN, GSM, and ISDN), decided to engage in the work of defining return channels using the same medium as the broadcast “downstream” one. Thus, the cable and then the satellite platforms have been endowed with their dedicated return channel, and it is now possible to provide the remaining terrestrial platform with a dedicated return channel. The result of this work is called DVB-RCT (Return Channel for Terrestrial system) and is intended to provide standard specification for interactivity in the UHF/VHF bands. Using the newly defined DVB-RCT standard as a companion of the worldwide proven, recognized, and adopted terrestrial DVB system, DVB-T is no longer limited to unidirectional broadcast. It can become a true terrestrial wireless interactive system. Following a general presentation of the DVB-RCT technical specifications, two projects dealing with the future of the DVB-RCT standard are presented in this paper.

The Digital Satellite Broadcasting System in Italy: Between Mix and Hybridism

This article sets out to investigate the development of the satellite TV phenomenon as one of the first steps towards the complete digitalisation of the media in Italy. Of major importance is the set of circumstances that led a small terrestrial broadcasting company, Telepiù, to become the biggest digital TV service provider in Italy and one of the most important within Europe. Before putting forward any hypothesis about the future of Sky Italia as a new player, it is necessary to analyse the most recent changes within the duopoly Telepiù and Stream. These changes took place against the background of the predominance of generalist broadcasters and were primarily driven by the opportunity to broadcast content that was not available to traditional media, in a situation characterised by economic and legislative weakness. Digital technology at present can be considered an “unpopular” medium: it doesn’t have social appeal because it doesn’t get onto the audience’s social agenda. This can be inferred from the low level of subscription up-take and is confirmed by evidence of widespread technological incompetence among customers. At first sight, satellite digital TV seems to be apart of a recent technological convergence trend sweeping Europe, targeting TV as a whole. But on closer inspection, it is narrowly focused in Italy on football and sport in general. Satellite digital TV in its current phase is built on access to football rights and is prevented from becoming a genuinely new broad- casting system because it is controlled by the narrow interests of its owners and controllers, the major players in the global entertainment market.

A quality assurance programme for NHS Digital TV services.

A quality assurance programme for NHS Digital TV services.

Digital TV in the convergent environment

The growth of digital TV heralds a seamless convergence of media, telecommunications, and information technology, offering viewers increasingly exciting, informative interactive programming. In countries such as the UK where digital TV services have become extensively available, the ground is prepared for a seamless convergence of media, telecommunications, and information technology interactivity is provided mainly by a combination of local storage (which is now becoming vast) and the Public Switched Telephone Network (PSTN), including mobile access. The industry is also investigating other return channels, such as those using satellites or the terrestrial TV antenna systems. Thus digital TV is a key element in the communications revolution. Where there is rapid growth in the number of homes with digital TV, there is likely to be a more favorable climate for the development of electronic commerce.

Digital TV comes down to earth

The introduction of digital television, albeit with only modest pretensions to glitz, is bound to invigorate competition among manufacturers and broadcasters. The BBC and commercial TV companies in Britain will launch what looks to be the world's first terrestrial digital TV (DTTV) service intended for nationwide viewing. The British services will be the first to use ground transmitters to send digital pictures and sound to an ordinary Yagi roof antenna of the type used for analog TV in Europe or even to indoor rabbit ears. Plenty of digital receivers should be in the shops, and pay TV services, both satellite and terrestrial, will be wooing hesitant viewers with special incentives. Most other countries in Europe are also getting ready to launch DTTV services. The author discusses the phase out of analog services, digital video broadcasting standards, data rates, encryption standard, and competing digital services.

Multimedia information broadcasting using digital TV channels

The structure of a new system used to broadcast multimedia information within a digital TV channel is outlined. The proposed scheme is based on the the Digital Storage Media Command and Control (DSM-CC) functions, and uses a newly developed protocol that allows to efficiently convey multimedia information. Such information has the same characteristics of HTML files used in WWW environments, as it may contain text, images, sounds and animation organized as an hypertext. The transport structure used is the MPEG-2 Transport Stream, which is the most standardized platform for the development of new digital TV services. A prototype software was developed to encode the file system by means of DSM-CC operations and include it in a MPEG-2 compatible Transport Stream.

Multimedia information broadcasting using digital TV channels

In this paper, the structure of a new system to broadcast multimedia information within a digital TV channel is outlined. The proposed scheme is based on the DSM-CC (digital storage media command and control) functions, and uses a newly developed protocol that allows to efficiently convey multimedia information. Such information has the same characteristics of HTML files used in WWW environments, as it may contain text, images, sounds and animation organized as hypertext. The transport structure used is the MPEG-2 transport stream, which is the most popular standardized platform for the development of new digital TV services. Prototype software was developed to encode the file system by means of DSM-CC operations and include it in a MPEG-2 compatible transport system.

Digital audio coding for visual communications

Current and future visual communications for applications such as broadcasting videotelephony, video- and audiographic-conferencing, and interactive multimedia services assume a substantial audio component. Even text, graphics, fax, still images, email documents, etc. will gain from voice annotation and audio clips. A wide range of speech, wideband speech, and wideband audio coders is available for such applications. In the context of audiovisual communications, the quality of telephone-bandwidth speech is acceptable for some videotelephony and videoconferencing services. Higher bandwidths (wideband speech) may be necessary to improve the intelligibility and naturalness of speech. High quality audio coding including multichannel audio will be necessary in advanced digital TV and multimedia services. This paper explains basic approaches to speech, wideband speech, and audio bit rate compressions in audiovisual communications. These signal classes differ in bandwidth, dynamic range, and in listener expectation of offered quality. It will become obvious that the use of our knowledge of auditory perception helps minimizing perception of coding artifacts and leads to efficient low bit rate coding algorithms which can achieve substantially more compression than was thought possible only a few years ago. The paper concentrates on worldwide source coding standards beneficial for consumers, service providers, and manufacturers.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Fiber-optic transmission of microwave 64-QAM signals

Experimental results on fiber-optic transmission of microwave 64-level quadrature amplitude modulated (QAM) signals at a 1.3 mu m wavelength at a 90 Mb/s transmission rate are presented. Two important methods of improving the system performance are discussed and demonstrated: laser intensity noise minimization and error-correction coding using a self-orthogonal convolutional code. The applicability of this transmission technique to the distribution of digital TV services is assessed. >