Direct Broadcast Satellite Research Articles

A microstrip antenna array for direct broadcast satellite receivers

A uniformly illuminated square subarray of 16 circularly polarized patch elements is developed. It can be incorporated into a full-size direct broadcast satellite (DBS) receiver antenna. A stacked circular patch microstrip configuration is used to achieve increased bandwidth. Experimental results for the return loss, bandwidth, radiation pattern, and gain are presented. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 15, 68–72, 1997.

Comparison of the design of a contoured-beam and an elliptical-beam satellite offset reflector antennas to cover the Taiwan island region for satellite communications

For the design of the satellite antenna for the future geostationary (GEO) satellite communication or DBS (direct broadcasting satellite) applications to serve the Taiwan Island region, it may be required to have a antenna beam which effectively covers the Taiwan region and reduces the antenna radiation level in the nearby area of mainland China. Two cases of the Ka-band (20 GHz) satellite antenna, a shaped offset reflector antenna to synthesize a contoured beam and an elliptical offset reflector antenna to generate an elliptical beam, have been studied. This paper presents the comparison and discussion of the antenna coverage performance of the two designs.

Circularly polarized dielectric-loaded planar antenna excited by the parallel feeding waveguide network

A new receiving planar array antenna for DBS (direct broadcasting satellite) is proposed. The element antenna is a short waveguide aperture mounted in the ground plane, loaded with a dielectric and polarizers, and excited through its side wall by another feeding rectangular waveguide. The gain of the element antenna loaded with a dielectric is so high that the grating lobes can be reduced sufficiently even if the element spacing in the array is wider than the wavelength in free space. Therefore we can reduce the number of the array elements, and parallel feeding by the low loss waveguide network can be feasible to provide a planar array antenna. This paper describes the experimental results of several kinds of the circularly polarized dielectric-loaded element antennas and the planar antennas fed by the waveguide network. In the 12 GHz band the planar antenna with 64-element radiators has a maximum gain of 31.9 dBi with an aperture efficiency of 94.7%, the 1 dB-down frequency bandwidth of the gain is about 800 MHz (6.7% for a center frequency of 11.85 GHz), and the frequency bandwidth of the axial ratio is less than 1 dB of 850 MHz (7.2%).

Globalization and policy choice: television and audiovisual services policies in India

Policies shaping the production and distribution of electronic broadcasting or audiovisual services in India have undergone tremendous changes from the 1980s to the 1990s. The number of channels and programming carried by Doordarshan, the state broadcaster, has grown. Private companies both from within and outside India now produce television programming and distribute it through direct broadcast satellites or cable television systems. The dominant account of the liberalization of audiovisual services policies in India focuses almost solely on the role of global economic forces and technical change. While policy choices have been constrained, many of these limitations arose from Indian decisions made about the role of broadcasting in the 1970 and 1980s, and from social and economic developments within India in the 1990s.

Challenges in a Digital, Server-Based Broadcasting Environment

DIRECTV, Inc., initiated operations at its all-digital Castle Rock Broadcast Center (CRBC) in Colorado on June 17, 1994. The broadcast center contains a 512 × 12 SMPTE 259M serial digital router, controls more than 300 digital VTRs, and transmits nearly 200 channels via the DIRECTV geosynchronous direct broadcast satellites. This paper describes the issues and challenges facing DIRECTV in evolving the CRBC and its other facilities toward a “server-based” architecture. Tentative conclusions may change as requirements change and technology matures. It is also intended to provide a basis for industry discussion of key issues.

Broadband Data Services over Residenial Access Networks

ese are truly exciting times for residential and business customers served by local telephone, cable television, and direct satellite providers. Perhaps for the first time, we are witnessing the application of computer networking techniques to telecommunication access network architectures. These local access options include fiber in the loop, fiber to the home, hybrid fibericoax, switched digital video, direct broadcast satellite, wireless microwave/RF links, broadband PCS, and so on. All these state-of-the-art access alternatives are being equipped with an overlaid TCP/IP data services delivery architecture to support high-speed interactive data services to the subscriber’s premises. Transmission rates from a few hundred kilobits per second to tens of megabits per second are envisioned using various digital subscriber line (xDSL over twisted pair) and RF subcarrier multiplexing (cable modems over coax) technologies. The ultimate objective is to equip the end user with high-speed access to the Internet, corporate intranets, and popular on-line services. This is with the grand intention of finally solving the last-mile bandwidth bottleneck and facilitating the deployment of advanced multimedia services such as work at home, distance learning, telemedicine, home shopping, electronic commerce, and high-speed Web access. This special issue is dedicated to provide up-to-date information on research topics, research results, and performance and economic comparisons of various access methods and architectures currently being considered for interactive broadband services (IBS) over residential access networks. The 1996 Telecommunications Deregulation Act allows both local and long-distance telephone service providers and television service providers to offer IBS to the home. Under this intense competition, the winning IBS providers would be those who can either use as much existing infrastructure as possible or cost-effectively and rapidly deploy access, transport, service, and management infrastructures. Research, investigations, standardization efforts, and field trials on all aspects of IBS to the home are progressing at full swing. We received more than 20 articles for publication in this special issue, but could accommodate only seven here. The reviewers selected the ones which fit

The design and implementation of TSBB for KOREASAT D-DBS (digital direct broadcasting satellite) system

The TSBB (transmitter station baseband) system is one of the main subsystems of the digital DBS system for KOREASAT. The TSBB subsystem processes, compresses, packetizes and multiplexes the program and data sources, and sends the multiplexed output to the RF/IF module for transmission. The TSBB has the following characteristics; a resolution of up to 720/spl times/480, 4/spl times/3 and 16/spl times/9 aspect ratios, closed caption, and multilingual language (up to 3 languages). The TSBB adopts MPEG-2 MP@ML for video processing, and MPEG-1 Layer II for audio processing. A data program is available at up to 2 Mbps. The TSBB also scrambles the program for subscriber or pay-per-view channels. We introduce the functional requirements, system design and system implementation for the TSBB. We show the test results for the TSBB functions which include video broadcasting, audio broadcasting, data service, encoder/multiplexer, and performance test.

The configuration of TSBB for Koreasat D-DBS (digital direct broadcasting satellite) system

The TSBB (transmitter station baseband) is one of the main subsystems of the D-DBS system for Koreasat. It pre-processes, compresses, packetizes and multiplexes the program and data sources, and send the multiplexed output to the RF/IF module for transmission. The TSBB has the following characteristics: a video resolution of up to 720/spl times/480, optional usage of an aspect ratio between 4/spl times/3 and 16/spl times/9, closed captioning, and multiple languages (up to 4 languages). The TSBB employs MPEG-2 MP@ML for video compression, and MPEG-1 Layer II for audio compression. Data programs are available at up to 2 Mbps. The TSBB also scrambles programs for subscription and pay-per-view channels. We introduce the system requirements, system design and system implementation for the TSBB. We also show test results for the TSBB functions which include video/audio/data broadcasting and encoder/MUX configuration, and test results for the TSBB performance.

The Internet in space: problems and solutions

With the advent of direct broadcast satellites and inexpensive minidishes, satellite broadcasters are competing with cable television providers by delivering hundreds of channels of digital video services to millions of customers without a wired infrastructure. Many of these broadcasters also want to compete with Internet service providers by delivering high-speed Internet access to homes and businesses. If satellite services have their way, users will no longer have to wait to enjoy multimegabit Internet data connections until the telephone company provides them with fiber-optic cable. The paper considers how space-based Internet service must overcome a fundamental problem before it can realize its full potential. While it is possible to bounce Internet data packets off geosynchronous-Earth-orbit (GEO) communication satellites, the protocol that ensures that the packets will arrive safely (TCP/IP) also slows satellite-based traffic to a relative crawl. This is because in space TCP/IP must carry data over distances that are much longer than the protocols were designed for. This creates transmission delays that make it impractical to download the large files of data, including images and multimedia products, that many organizations need. However, researchers who are looking for solutions to this problem have come up with several promising proposals.

Direct satellite broadcasting in the Arab Gulf region: Trends and policies

During the past decade, the six Arab Gulf Cooperation Council (AGCC) states, comprising of Saudi Arabia, Oman, the United Arab Emirates, Kuwait, Qatar, and Bahrain have taken long strides in the development of their mass media and national telecommunications infrastructures. One of the areas positively affected by this trend has been direct satellite broadcasting and reception. Not only have AGCC states made possible their populations' exposure to DBS television programming, but they themselves have become active participants in international satellite broadcasting, some of them are even beaming their TV materials on an around-the-clock basis. This study argues that the rise of DBS in the Gulf is part of a three-decade trend of commu nications development in the region whereby national broadcasting systems in the six states have acquired high degrees of sophistication and maturity. The study notes that major DBS broadcasters to the Gulf region range in background from CNN International, to Middle East Broadcasting Center, London, to the French International Channel (CFI). Local Gulf popula tions watch DBS programs through direct-to-home transmissions, telecasts of selected foreign and Arab satellite services by national TV channels, and finally through microwave distribution systems. The authors note that while DBS in the Arab Gulf region is here to stay, it has to be approached with a balanced vision that takes into account the national interests of Gulf societies and media systems. While total blackout approaches seem to be unrealitistic in light of accelerating innovations in DBS reception techniques, openness to international television via satellite should serve as a means of fostering intercultural interactions and of enhancing national media performance.

A flexible transmission technique for the satellite ISDB system

A new transmission technique which can achieve suitable quality and reliability for satellite ISDB (Integrated Services Digital Broadcasting) is introduced. The transmission system for satellite ISDB must have high spectrum efficiency, continuous service availability and also superior flexibility in its transmission scheme. This paper first studies appropriate transmission schemes, taking account of the 12 GHz band DBS (direct broadcasting satellite) system. Then, employing a hierarchical transmission technique and a newly proposed TMCC (transmission and multiplexing configuration control) signal, it describes the requirements for satellite ISDB. The hierarchical transmission extends the service availability under heavy rainfall conditions. The TMCC signal can change the transmission configuration depending on the program content and the weather conditions. In addition, a generalized method for the design of transmission configurations for satellite ISDB is presented.

New AFC tracking algorithms for digital DBS receiver

Two new automatic frequency control (AFC) tracking algorithms are proposed for QPSK demodulation in a digital direct broadcasting satellite (DBS) receiver. These are called rotational decision directed AFC(RDDAFC) and decision device embedded AFC(DDEAFC). In order to prevent the presence of the residual phase difference by the CPAFC [Natali 1984] as well as the AFC based on the tan/sup -1/ circuit [Ishigawa 1992], the RDDAFC rotates the decision boundary for the kth received symbol by the frequency detector output of the (k-1)th received symbol while the DDEAFC uses the product of the kth received symbol and the decision device output before passing through the cross product discriminator. It is shown that the total pull-in time of the RDDAFC and PLL was 0.13 msec with a carrier frequency offset of 2.4 MHz when the S/N equals 2dB while 0.2 msec is for the DDEAFC.

Pseudomorphic AlGaAs/InGaAs/GaAs HEMTs in low-cost plastic packaging for DBS application

0.2 µm gate length pseudomorphic AlGaAs/InGaAs/GaAs HEMTs in low-cost plastic packaging have been manufactured in our laboratory. The PHEMTs show typical peak extrinsic transconductances of 390 – 430 mS/mm. From S-parameter measurements, the PHEMTs show typical current-gain cutoff frequencies of 65 – 72 GHz. The devices on-wafer exhibited 0.40 – 0.47 dB noise figure and 12.6 – 13.5 dB associated gain at 12 GHz, respectively. The authors report the first demonstration of devices in a plastic packaging with 1.0 – 1.2 dB noise figure and 9.5 – 9.9 dB associated gain. The volume production of high performance AlGaAs/InGaAs/GaAs PHEMTs in plastic packaging is suitable for direct-broadcast satellite applications.

Tuning In, Tuning Out: The Strange Disappearance of Social Capital in America

It is a daunting honor to deliver the inaugural Pool Lecture. Ithiel de Sola Pool was a brilliant, broad-gauged scholar whose interests ranged from the Nazi elite to direct satellite broadcasting, from the first rigorous computer simulation of electoral behavior to the development of network theory, from which he invented small world research. He helped found the field of political communications. A graduate of the University of Chicago's political science department during its classic golden age, and first chair of the MIT political science department, Pool must also have been a remarkable teacher, for his students continue to contribute to our understanding of technology, communications, and political behavior. When I accepted this honor, I did not guess how close my own inquiry would lead me to Pool's own professional turf. I shall return to the contemporary relevance of Pool's insights at the conclusion of this talk.

In‐orbit test of the first Hughes United States direct broadcast satellite

AbstractThis paper describes the in‐orbit test of the first United States direct broadcasting satellite (DBS‐1) developed by Hughes Space and Communications (HSC) for Hughes Communications Galaxy, Inc. and DIRECTV Inc. This satellite provides direct broadcast of digitally compressed television channels across the United States for service providers DIRECTV™ and United States Satellite Broadcasting (USSB).Following a brief description of the communication system of the spacecraft, the in‐orbit test set‐up and the measurements that were performed are described. Measurements which have not been described elsewhere (antenna contour verification, modulated e.i.r.p., e.i.r.p. with wide band energy dispersal function (EDF), auto saturation, etc.) are covered in some detail.Finally, the results of the in‐orbit test of DBS‐1 which was performed in January 1994 are presented.

What's behind DBS services: MMIC technology and MPEG digital video compression

This paper discusses recent developments in Direct-Broadcast Satellite (DBS) television systems, and specifically how these developments are implemented using today's MMIC technology. A brief review of Raytheon's experience in supplying low cost GaAs devices to the commercial DBS market place is included. A description of a dual-channel downconverter is provided as an example of applying GaAs MMIC technology to the advanced technical needs of the DBS market. A discussion of the MPEG-2 digital compression standard and its relationship to DBS is also included. >

Variable output power 21 GHz direct broadcasting satellite systems

This paper describes the 21 GHz band Direct Broadcasting Satellite transponder for wide RF band HDTV and reduction of satellite weight. The most difficult problem with this frequency band is rain attenuation. We studied a variable output power transponder system for a contoured six-beam antenna covering all of Japan. The output power of transponders corresponding to rain areas are boosted from the normal margin of 5 dB (the worst month service time rate 95%) to 9 dB (99%). This variable output power method can decrease about 30% of the satellite power and weight.

Direct broadcast satellites in Japan: A case study in government-business partnerships

Abstract The following case study examines government-business partnerships in the planning and implementation of direct broadcast satellite (DBS) communications in Japan. The country's decision to launch the world's first DBS system demonstrated a national commitment to advance the cause of a highly sophisticated technology. For Japan's Ministry of Posts and Telecommunications DBS was clearly a high-profile project that would invite both national and international attention. Less clear were the unintended consequences that would result from planning a new system of broadcast communication that involved balancing the unique requirements of a non-profit corporation in the form of NHK and Japan's five major commercial broadcasters.

The direct broadcast satellite industry in the U.S.: Development and economic concerns

Throughout 1992 and 1993, announcements by DirecTV and USSB promised the initiation of Direct Broadcast Satellite service in the United States would occur before the end of 1994. The two services were indeed launched in 1994 and a new industry is emerging. This industry is different from the traditional wire‐based and terrestrial broadcast means of television program delivery to individual homes since DBS is space‐based. DBS is also different from the TVRO industry which is space‐based since, unlike TVRO, DBS services are specifically and solely designed and intended for home reception. This paper first reviews the evolution of American DBS in the 1980s and 1990s. Later an analysis explores some economic concerns with respect to American DBS ventures. This paper concludes that key economic determinants of success include: 1) the presence of a large‐enough subscriber base to justify the investment of at least one DBS provider; 2) the absence of excessive and predatory barriers to entry created by the alter...

Analysis and design of a Ka‐band satellite shaped offset reflector antenna for producing a contoured beam to cover the Taiwan region

Abstract Analysis and design of a Ka‐band (20‐GHz) satellite offset‐fed shaped reflector antenna with a single feed for producing a contoured beam to cover the Taiwan region is presented. The design of this shaped reflector antenna is for future geostationary (GEO) satellite communication or DBS (direct broadcasting satellite) applications to serve the Taiwan region. The geometrical optics (GO)/aperture field (AF) method and aperture phase optimization procedures are employed for reflector surface shaping to produce the desired contoured beam. The physical optics (PO) method is used to accurately calculate the far‐field radiation pattern. Numerical simulation results show that the designed shaped reflector produces a Taiwan region converge beam and effectively reduces the antenna gain level in the nearby area of mainland China. Further reduction of the antenna gain level can be achieved by shifting the boresight direction of the satellite antenna for a certain small angle.