December 1998

ABC, Fox, NBC, and PBS stations. Together, these stations will reach 39% of U.S. TV households with DTV and HDTV signals. By November 1, 1999, 12 CBS DTV/HDTV stations will be on-the-air along with 29 ABC, Fox, NBC, and PBS stations for a total of 41 digital stations. At this time 61% of U.S. TV households will be able to access digital TV and HDTV. In Canada, the Canadian Task Force on the Implementation of Digital Television recommended: The Task Force unanimously believes that a common North American standard for terrestrial Advanced Television Services will benefit Canadian consumers and the Canadian broadcasting systems. Further the Task Force recommended: By the end of 2007, two thirds of each broadcasters schedule and two thirds of new Canadian content productions should be available in the HDTV format. The Canadian Government is presently considering all the Task Force recommendations. Action on finalizing the regulations is expected later this year. The ATSC transmission standard supports a hierarchy of open, nonproprietary scanning formats with HDTV at the highest level, and includes SDTV and digital datacasting. Note the dominance of 1080i equipment and the near absence of yet-to-be designed 720p equipment. 1080i will be the mass-market HD format in America. The latest information from the consumer equipment suppliers in America shows Native Display Format manufacturers plan to decode all the ATSC formats, including HDTV, but plan to display only 1080i and the 480i & p formats. The 720p format will not be displayed in its native quality, but rather, will be converted to 480i, 480p or 1080i for display. Major consumer equipment manufacturers plan to produce DTV/HDTV receivers beginning this summer for marketing this autumn ready for the 1998 Christmas buying season. Direct view, front and rear projection, and flat screen models will be offered over the next 12 months. Pricing is not broadly known, but some manufacturers are announcing initial DTV/ HDTV receivers in the $2,500 to $8,000 and up range. With so many competitors entering the market, prices are expected to fall rapidly. In production, the widespread use of 1080i as an HDTV production format is in harmony with the ITU Recommendation ITU-R BT.709 which states in part: Considering: - that parameter values for HDTV production standards should have maximum commonality; - that an active image format of 1920 pixels by 1080 lines provides square pixels sampling, with attendant advantages for interoperability between various applications including digital television and computer imagery; Recommends: - that for new implementations, particularly where interoperability with other applications is important, systems described in Part II (of document ITU-R BT.709) are preferred. Part II describes the CIF systems as: 1080/60/2:1; 1080/60/1:1 and 1080/50/1:1; 1080/50/2:1 with 1920 samples per active line at an aspect ratio of 16:9. This recommendation was strongly supported by the Technical Committee of the World Broadcasting Unions (WBU-TC) in 1997 in their statement which reads: The World Broadcast Unions Technical Committee strongly supports the adoption of unique standard for program production and exchange of high definition television. This will lead to easier and better exchange of HDTV programs, and lower equipment costs. It will accelerate the move to high definition throughout the world. The WBU-TC recommends that the unique standard should be the so-called HD-CIF standard which has a 1080 line by 1920 sample x 50Hz/60Hz scanning system. This standard should be used for HDTV production equipment. Studio equipment manufacturers are being encouraged to set in motion the means to provide equipment to this standard. This statement was reaffirmed at this years meeting of the WBU-TC in Krakow, Poland on April 26. Thus, we finally have a single worldwide common image format standard for high definition program production and program exchange based on the ITU Recommendation BT.709. In considering the importance of HDTV broadcasting, it is vital to understand that wide screen high definition is not just pretty pictures for todays small screen TV sets. Rather, it is a wholly new digital platform which will support the larger and vastly improved displays now in development for commercialization HDTV. Viewed on such large wide screen displays will create an entirely new viewing experience in the home, and consumers will want that experience. Those who believe, or want to believe, that the public will never want wide screen digital HDTV when it is offered, are taking a bet-the-business gamble. More-of the-same standard definition, 525 or 625 line, digital transmissions are unlikely to capture the market, unlikely to sell digital receivers in quantity, and will give way to HDTV worldwide! For its part, America will stick to the digital transition with unwavering enthusiasm. The American writer, Ralph Waldo Emerson, expressed this best in 1850 when he wrote: Nothing great was ever achieved without enthusiasm. (received 29 May 1998)

Mitsubishi Electric ADVANCE

TECHNICAL R EPORTS

Overview: The Present and Future of Digital TV Broadcasting
by Tokumichi Murakami, Tetsuya Yamaguchi, Dr. Tommy C. Poon, Dr. Paul A. Ratliff and Dr. Tamotsu Nomakuchi*
This report addresses policy, technology and standards development as nations prepare for the advent of the era of digital television, and describes the current state of development of digital broadcasting systems and services. The capabilities of broadcasting equipment developed by Mitsubishi Electric, including codecs, gathering and distribution systems, semiconductor products and consumer receivers, are also introduced. Digital Broadcasting Systems and Development Schedule The transition to digital television raises numerous issues including government policy, broadcast technology, consumer electronics and market acceptance. Fig. 1 shows timelines for the introduction of digital services to satellite, terrestrial and cable broadcasting in Japan, the United States and Europe. Table 1 summarizes specifications of
1996 and earlier BS Satellite CS Jul. 95 Technical standard (TTC report) Terrestrial Jun. 96 Services started
1997 Sep. Tentative technical standard Dec. Feb.
1998 Nov. ARIB standard (version 1)
1999 Jun. ARIB standard (version 2)
2000 and later Dec. 2000 Services start
Technical standard (TTC report)
DirecTV Japan services started
Sep. Draft tentative technical standard May 96 Cable Technical standard (TTC report) Service trial began May
Sep. Tentative technical standard Jul. Services started

Nov. Service trial began

Apr. Technical standard (TTC report)

Fall Channel plan

Around 2000 Services start

Analog broadcasts end

Transition to fully digital full-service broadcasts
Dec. 96 Terrestrial FCC selects DTV standard

Nov. Services start

May Four major networks begin broadcasts to 10 major metropolitan areas (30% of households)

May 2003

Four major Digital Analog networks conversion broadcasts broadcast complete end to 30 major metropolitan areas (55% of households)

Satellite

Dec. 94 Standards adopted (EN300421, DVB-S)
96 Services started in Germany, France, Italy Mar. Standards adopted (EN300744, DVB-T) 98 Services started in UK, Spain, Sweden

Europe

Terrestrial
Dec. 94 Standards adopted (EN300429, DVB-C)
98 Services started in Germany
Key TTC: Telecommunications Technology Council
Fig. 1 Digital broadcasting implementation schedules.
*Tokumichi Murakami is with Information Technology R&D Center, Tetsuya Yamaguchi with Koriyama Works, Dr. Tommy C. Poon with ITA, Dr. Paul A. Ratliff with ITE-VIL and Dr. Tamotsu Nomakuchi with Corporate Research and Development.

Table 1 A Summary of Digital Broadcasting Systems
Japan Baseband signal 1080i: 1920 or 1440 pels x 1080 lines, 30f/s 480i: 720 pels x 480 lines, 30f/s 480p: 720 pels x 480 lines, 60f/s 720p: 1280 pels x 720 lines, 60f/s (verification required) 1080p: 1920 or 1440 pels x 1080 lines, 60f/s (under study) US (ATSC) 1080i: 30f/s 1080p: 24 or 30f/s 720p: 24, 30 or 60f/s 480p: 24, 30 or 60f/s 480i: 30f/s and others (picture format) Europe (DVB) 576i: 25f/s (4:3 &16:9) 1152i, 1080i/p: 25 f/s (16:9 & 2.21:1) 720p, 576p: 25, 50f/s(16:9& 2.21: 1 or 4:3) and others (for 60Hz countries: 1080i/p: 30f/s, 1080p: 24f/s 720p: 24, 30, 60f/s, 480i: 30f/s, 480p: 24,30,60f/s and others) MPEG-2 video, MPEG-2 audio
Source coding (video, audio) Multiplexing Application Information rate (Mbit/s) Out coding Transmission Inner coding Modulation Bandwidth (MHz)

MPEG-2 video, MPEG-2 AAC

MPEG-2 video, Dolby AC-3 MPEG-2 transport stream

Satellite (BS) 52.2

Terrestrial (draft) 23.4 RS (204,188)

Cable 29.2

Terrestrial 19.39 RS (207, 187)
Satellite 29.2 (at 27MHz)
Terrestrial 24.1 RS (204, 188)

Cable 38.1

Trellis, convolutional PSK 34.5
Convolutional OFDM + PSK, QAM 6

QAM 6

Trellis

Convolutional

Convolutional OFDM + PSK, QAM 8

8-VSB 6

QPSK 26~54
Key AAC Advanced Audio Coding

RS Reed Solomon

Note: In the specifications 1080i, 480p, etc., the numerals indicate the number of active lines, the letter "i" indicates interlace scanning and the letter "p" progressive scanning. For terrestrial broadcasting, 544 or 480 pels x 480 lines, 60f/s can also be used.
digital broadcasting systems. Virtually all of the development work in digital broadcasting source coding and multiplexing technologies is based on the standards established by the Moving Picture Experts Group, Phase 2 (MPEG-2). Japan National policy is directed toward establishing digital transmission channels for satellite, terrestrial and cable distribution within a few years into the new millennium. The CS satellite has been beaming digital broadcasts to the nation since 1996. The BS satellite will mainly use three digital broadcast formats: 480i, which consists of 720 pels x 480 lines and is similar to conventional TV with interlaced scanning, 480p, similar to 480i, but with progressive scanning, and 1080i, which consists of 1,920 pels x 1,080 lines for HDTV signals. MPEG-2s Advanced Audio Coding (AAC) was selected for high sound quality. Trellis-coded 8 phase-shift keying was chosen as the modulation system for its efficient frequency utilization. Tentative technical standards have been established for digital terrestrial broadcasting, and practical broadcasting methods are under study. These standards are distinguished from those of other nations by support for robust mobile reception, which is expected to encourage integrated products such as handheld receivers with personal digital assistant (PDA) functions and vehicle-mounted receivers with car-navigation functions. Accord-

ing to the Ministry of Posts and Telecommunications schedule, test trials of digital terrestrial broadcasting in the Tokyo area will begin in 2000 and country-wide service will begin by 2006. Analog broadcasting will be phased out by 2010. United States In 1994, several companies including DirecTV, USSB and Primestar began multichannel digital satellite broadcasts and now serve more than five million subscribers. The Federal Communications Commission (FCC) has been studying digital terrestrial broadcasting since 1987. In 1993, broadcast-related companies formed the Grand Alliance aimed at integrating standards for digital broadcasting. The Grand Alliances Advanced Television Systems Committee established the ATSC standard in 1995, which the FCC selected for its Digital Television (DTV) standard in 1996. The final choice among the 18 formats specified in the ATSC standard is left to the discretion of the broadcasting companies. According to the FCCs implementation schedule, the four major networks will inaugurate digital terrestrial broadcasting services in ten metropolitan areas with the largest numbers of viewers by May 1999 and in the 30 largest cities by November 1999. Other commercial broadcasters will follow by May 2002, and public television stations by May 2003. Analog broadcasting will be phased
TECHNICAL R EPORTS out in 2006. The four major networks and the Public Broadcasting Network (PBS) began offering digital broadcasting services this fall, 1998. The launching of the space shuttle carrying Senator John Glenn and Astronaut Chiyaki Mukai on October 29 was safely accomplished and simultaneously broadcast by CBS using Mitsubishi Electrics HDTV codec for digital transmissions to major cities including New York and Los Angeles. Interest was high, and the broadcasts were a great success. Europe The EU is setting policy for digital broadcasting development in the form of EC Directives, while the Digital Video Broadcasting (DVB) Organization, a private-sector standards body of broadcasters, network operators and manufacturers, together with EU and national government representatives, has developed a family of digital broadcasting standards. The European Telecommunication Standards Institute (ETSI), representing some 34 countries of a greater technical Europe, has established the final standards. Exploitation began with digital satellite broadcasting services using quadrature phase-shift keying (QPSK), begun by companies such as Telepiu (Italy), Canal Satellite (France) and recently BSkyB (UK). These are based on the DVB-S standard (EN 300421) completed by ETSI in 1994. Cable soon followed with the DVB-C standard (EN 300429, also completed in 1994), using up to 256-quaternary amplitude modulation (QAM). In its established markets, cable generally provides a complementary delivery service of largely the same program services available off-air, but not always in the same service area, and some other one-stop attractions to subscribers. The latest arrival is digital terrestrial TV (DTT) broadcasting, with its more complex, but highly multipath-resistant, coded orthogonal frequencydivision multiplexing (COFDM) form of modulation. This employs selectable modulation from QPSK up to 64-QAM on nominal 2000 or 8000 OFDM carrier implementations within a 7 or 8MHz TV channel. From a DVB-T draft in 1995, ETSI released the final standard (EN 300744) in 1997. The UK has recently implemented services with a mix of simulcasting existing analog program services and new digital-only programs supplied by both existing and new commercial providers (ON digital). The rapid deployment of major new digital transmitter networks was facilitated by the UK Digital TV Groups influential implementation standards for interoperability, known as the D-book. Although the current digital broadcasts in Europe are only standard-definition TV (576i, 50Hz), HDTV forms part of the DVB standards, with commercial services on the horizon, especially as the standards have been extended for use outside Europe in both 50 and 60Hz countries. Indeed, DVBHDTV has been demonstrated at broadcasting trade shows such as ITVS 95 & 97 and NAB 98. Digital Broadcasting Standardization Standardization of digital broadcasts is essential to ensure that various types of broadcasting equipment can be linked (interconnectability), different services can work alongside each other to all receivers (interoperability), and that content can be made available over heterogeneous networks (interavailability). Fig. 2 illustrates the relationships between international, regional and privatesector standards organizations. Broadcast-related international standards for

A Model Digital Broadcasting Station
by Susumu Oka and Norihiko Nakazawa*
Mitsubishi Electric has assembled a model digital broadcasting station to test equipment and systems for delivering digital programming via satellite, terrestrial and cable broadcasting networks in Japan, Europe and the United States. The model station serves as a testbed for checking specifications compliance and optimizing the design of production systems. Digital Broadcasting Systems MPEG-2-based video and audio coding and multiplexing technologies are at the focus of standards and equipment development as European, American and Japanese broadcasting stations prepare to deliver new services using digital signal formats. Digital broadcasting stations will provide a variety of new services over satellite, terrestrial broadcasting and cable distribution networks using a content-gathering, distribution and broadcasting system similar to that illustrated in Fig. 1. System equipment based on computers and highspeed networks must be developed and optimized while complying with the requirements of the relevant international and regional standard organizations including the International Standardization Organization (ISO), International Engineering Consortium (IEC), Digital Audio-Visual Council (DAVIC), Advanced Television Systems Committee (ATSC), Digital Video Broadcasting (DVB) and the Association for Radio Industries and Businesses (ARIB). A Model Digital Broadcasting Station Mitsubishi Electric is developing digital broadcasting equipment and has assembled a model

CONTENT GATHERING

DISTRIBUTION

BROADCASTING

Satellite Satellite broadcasting

SNG truck

Source acquisition

Program distribution

Terrestrial broadcasting
Source acquisition Cable network FPU Microwave link High-speed digital network Local station - Local program and commercial production - Program editing - Coding and multiplexing - Commercial insertion - Program switching Cable station Public subscriber telephone network, Internet
Main station - Acquiring source material - Program and commercial production - Coding and multiplexing - Generating ancillary data - Passing control data between stations
Key SNG: Satellite news gathering FPU: Field pick up
Fig. 1 A digital content-gathering, distribution and broadcasting system.
*Susumu Oka and Norihiko Nakazawa are with the Information Technology R&D Center.

Satellite broadcasting

Subscriber subsystem

Digital SNG truck

MODEL DIGITAL BROADCASTING STATION Baseband subsystem Coding and program multiplexing subsystem HDTV encoder SDTV encoder Terrestrial broadcasting Broadcasting system, transmission coding and modulation Cable station Transmitter, links to other stations Monitoring subsystem

Receiver, links to other stations Camera VCR

Routing switcher

To other stations
Media storage subsystem Remote database Video server
Satellite links, microwave links, high-speed leased lines
Management subsystem Station management server Conditional access mgt. server SI/EPG server

Program demultiplexer

HDTV decoder SDTV decoder Stream analyzer Public subscriber telephone network, Internet

High-speed leased lines

Commercial storage system
Monitoring control Local LAN

Broadcasting scheduler

Subscriber management server
Fig. 2 A model digital broadcasting station.
digital broadcasting station (Fig. 2) that will serve as a testbed for developing commercial systems. The model station is configured as functional blocks. The baseband subsystem handles raw uncompressed video streams received from digital cameras and VCRs or other stations. The coding and multiplexing subsystem compresses and multiplexes program source material. The media storage subsystem includes media storage equipment and a data-broadcasting server. The management implements program-transmission control, electronic program guide (EPG) and conditional access functions. The monitoring system is used to verify the normality of the outgoing transmissions. The other key element in the system is the subscriber subsystem, a compatible digital broadcasting receiver that decodes the compressed and multiplexed programs, delivering video, audio and data content to the viewer.
Evaluating Using the Model Station Fig. 3 shows a verification model developed to ensure the compatibility of our model station equipment with the satellite, terrestrial and
Service domain Markets Japan, Asia, United States and Europe, etc. (satellite, terrestrial, cable) Functional implementation Functional implementation Technical Domain Tools (video coding, audio coding, multiplexing, AV synchronization, etc.) Specification requirements
System domain Specifications, function, performance (MPEG-2 encoder, program multiplexer, etc.)
Specification requirements
Fig. 3 Verification classes for model station.
CODING AND PROGRAM MULTIPLEXING SUBSYSTEM AV encoder Program multiplexer AV encoder 6

SUBSCRIBER SUBSYSTEM Broadcasting system 6 MONITORING SUBSYSTEM AV decoder Receiver Monitor
GUI evaluation, service verification

Shared EPG server

3 MANAGEMENT SUBSYSTEM Program broadcasting 1 scheduler SI/EPG 4 editor SI/EPG compiler 5 Key 1 Own station schedule data 2 Program information 3 Other stations' schedule data 4 Broadcast-ready EPG data 5 Transmit SI/EPG data 6 MPEG-2 transport stream 7 Receive SI/EPG data
Program demultiplexer AV decoder SI/EPG monitor 7

2 Program data server

Syntax verification, transmit/receive comparison testing, transmission interval verification
Fig. 4 Verification flow for an electronic program guide.
cable broadcasting services of Japan, Europe and the United States. Conformance verification addresses standards compatibility and related technical issues. Compliance verification addresses system specifications and connectivity issues. Interoperability verification addresses backward compatibility with analog broadcasting services and other adaptations required to meet viewer and market needs. Fig. 4 shows the verification model for a proposed electronic program guide (EPG) service that will allow verification of the EPG data syntax, transmission interval, and viewer display functions. A complete testbed for digital broadcasting systems, Mitsubishi Electrics model station is an important milestone on the road to delivering digital program content worldwide. u
Digital Broadcasting and Home NetworksA DAVIC Perspective
by Yoshiaki Kato and Shinji Akatsu*
This article reports on standardization activities for MPEG-2-based high quality audiovisual services by the Digital Audio Visual Council (DAVIC). DAVIC is an industry association working towards consensus on interoperability standards for future audiovisual services in applications areas ranging from digital broadcasting to home networks. The DAVIC Digital Video Distribution System DAVIC was established in June 1994, when MPEG-2 standards had been completed and broad-band networks such as asynchronous transfer mode (ATM) were becoming commercially available. DAVIC has been working on industrial standards for interoperability of equipment, systems, applications and content in digital broadcasting, interactive video systems and point-to-point communications. Fig. 1 shows the DAVIC system reference model. The DAVIC model includes a service provider system, a delivery system and a set-top box. It also specifies a number of reference points in the system (A1, A9, etc.) The delivery system consists of a core network of ATM or other high-speed backbone network and an access network that delivers content to individual users through subscriber link technologies, such as asymmetric digital subscriber line (ADSL), fiber to the curb (FTTC), hybrid fiber coax (HFC), or satellite. The application program interface (API) standards for the set-top box include the MHEG-5 runtime engine and a Java virtual machine which is hardware and operating-system independent. Five logical information flows are defined between subsystems. S1 is a realtime unidirectional stream of MPEG-2 encoded video and audio data, and flows from the server to the set-top box. S2 is a bidirectional flow between the server and the set-top box for application control and application data that is managed by the user-touser protocol specified in the MPEG-2 digital storage media command and control (DSM-CC) standards. S3 carries session control signals under the MPEG-2 DSM-CC user-to-network protocol. S4 carries connection control signals that manage an individual call. S5 carries network control signals for the delivery system. Fig. 2 shows the protocol stack at point A9 in the system reference model. DAVIC Home Network Consumer electronic equipment with digital control interfaces will eventually be integrated into a home network. Home networks will link a digital broadcasting receiver or set-top box with

Simple profile Main profile
SNR scalable Spatially profile scalable profile High profile

422 profile

Multiview profile
Fig. 2 Profiles and levels specified in MPEG-2.
ated with stereo and multilingual broadcasts. In AAC, MPEG-1 compatibility is sacrificed for higher coding efficiency. AAC includes three profiles: Main, where sound quality is given priority; Low Complexity (LC), which minimizes code processing cost and hardware scale; and Scalable Sampling Rate (SSR), a variable bandwidth option which further reduces decoder complexity by lowering the signal bandwidth to suit the particular application. The MPEG-2 System part handles multiplexing and synchronization. Multiplexing is the task of breaking audio and/or video streams into packets. A transport stream (TS) and program stream (PS) are defined. A TS can transport multiple programs using fixed-length packets, and is used in channels that are subject to errors. A TS can also transmit information about programs and program data streams for implementing electronic program guide (EPG) and program selection functions. A PS, which has a undefined packet length and can carry only a single program, is intended for DVD and other recording media. Digital Broadcasts and MPEG-2 Different countries are implementing a variety of MPEG-2 based digital TV broadcasts. The Digital Television (DTV) system being developed
in the United States defines 18 picture formats. The final selection among these numerous alternatives is being left to the marketplace, and each of the television networks has announced different policies. In Japan, the MPEG-2 Main profile and Main level (MP@ML) have been adopted for CS digital broadcasts, and the High level has been adopted for BS digital broadcasts. For audio encoding, the United States has adopted Dolby Laboratories AC-3 system, while Europe is using BC. Japan has adopted BC for its CS broadcasts and the newly established AAC standard for broadcasts. Both BS and CS employ MPEG-2 multiplexing, while different methods are being used for error-resistant framing and modulation. The Present and Future of MPEG Standards MPEG work is underway to complete version 1 of the MPEG-4 standard by a target date of December 1998. MPEG-4 will likely be used through lossy, low-speed channels such as wireless communications and Internet connections. Its low bit-rate capabilities may also be used for multiplex programming or data transfer via digital broadcasting channels. MPEG-4 consists of System, Visual and Audio parts. The System part handles multiplexing and synchronization management, and defines scene description

Bit stream

Good afternoon
Input Audio object coding Video object coding Audio object decoding

Demultiplexing

Output

MITSUBISHI

Text object coding Computer graphics object coding Scene description coding ENCODER
Text object decoding Computer graphics object decoding Scene description decoding DECODER

Composition

Multiplexing

Video object decoding

User controls

Scene description

Fig. 3 MPEG-4 coding and decoding.
methods. Scene description combines multiple AV objects into a single composite screen (Fig. 3). The visual part permits objects recorded in the image to be handled as independent logical objects. In a continuation of the natural image object coding in MPEG-2 and other standards, the MPEG-4 visual part defines texture and object shape coding methods. Audio coding methods can be selected to suit the particular audio object type, typically voice or music. Coding tools for high-quality audio and speech synthesis are also defined. Studies for MPEG-7, the successor to MPEG4, have begun in earnest. MPEG-7 targets standards for supplementary information about program content such as description, affiliation and characteristics that will facilitate program searches. The standards are planned for completion in the year 2001. The MPEG standards are based on coding technologies developed for video conferencing and other multimedia applications. Mitsubishi Electric has actively participated in standards development since commercial video conferencing systems have been available and is continuing to contribute to the development of international standards. The standards prescribe the narrowest set of conditions required to ensure compatibil-
ity, giving manufacturers wide latitude to select function and performance to suit hardware constraints and application requirements. Mitsubishi Electric has been pioneering equipment and systems in step with standardization activities, retaining proprietary technologies for commercial implementations of existing standards while continuing research toward new standards. u
Digital Broadcasting Codecs
by Okikazu Tanno and Takashi Honda*
Digital broadcasting coder-decoders (codecs) are a critical component of developing digital broadcasting technologies. Mitsubishi Electric has developed two codecs and a program multiplexer for program distribution, terrestrial and satellite broadcasts and cable delivery. This report introduces the Model MH-1100 codec for HDTV applications, the Model BC-1100 codec for SDTV applications and the Model TM-1100 program multiplexer. Performance Requirements Image quality is the dominant requirement on codecs for broadcasting applications, since the quality of the compressed video signal determines the quality available to broadcasting services. For example, a codec capable of delivering HDTV quality images in the 6MHz bandwidth used by current analog TV broadcasts would make the transition to digital broadcasting highly attractive. A second major requirement is functionality to support multiplexing of several program channels and data for electronic program guides and other purposes. Fig. 1 shows the basic configuration of Models MH-1100, BC-1100 and TM-1100 for implementing various digital broadcasting functions. The Model MH-1100 HDTV Codec Mitsubishi Electric has been developing coding technologies for HDTV applications for several

Key Helicopter : Raw source material transmissions : Interstation program transmissions
Portable earth station Portable earth station
Broadcasting center with earth station
Broadcasting center with earth station Mobile earth station
Fig. 1 A satellite newsgathering network.
*Kenichi Asano is with Information Technology R&D Center and Gen Sasaki with Communication Systems Center.
four commercial networks. Codecs are one of the cornerstones of digital broadcasting technology, pumping video and audio streams with maximum efficiency over satellite links from remote sites to the program production centers of the major broadcasting networks. u
Fig. 2 VX-3000 Series codec.
Video Codec Video codecs have made it possible to convert analog SNG networks to digital because codecs increase link utilization efficiency and increase the tolerance of the satellite link to fading and other error sources. At the transmitter, the codec compresses the source data, which can include video and audio streams and auxiliary data, then multiplexes the compressed data, adds robust error-correction codes and performs digital modulation. At the receiver, the codec demodulates the incoming signal, performs error correction, and then decodes the original video, audio and auxiliary data. SNG codecs support several special functions suited to SNG applications. First, they support high picture qualitybetter than analog networksto provide a sufficient margin for editing and other processing. Second, they offer short processing delay, which supports realtime conversations in live on-site reports. Third SNG codecs are light enough for mobile or portable use. Fourth, they use strong error-correction codes that prevent line disturbances from disrupting transmissions. Mitsubishi Electric has developed and is delivering MPEG-2-compliant VX-3000 Series SNG codecs with these attributes. Fig. 2 shows a photograph of a VX-3000 Series codec. An original coding-control technology provides high picture quality for broadcasting use while the unit is small enough for portable applications. The codecs are already in operation at Japans

Fig. 6 Photomicrograph of display processor. Table 2. Display-Processor Chip Specifications
Process Chip area Power supply voltage Power dissipation Clock frequencies Number of transistors Internal memory Number of filter taps Package 0.5 m CMOS two-layer metal 14.9 x14.9 mm2 3.3V 2.9W 54/54.05, 74.18/74.25, 13.5/13.51 MHz 1.9 million 284kB 188 388-pin plastic BGA

SDRAMs

filter. In order to solve this problem, an automatic filter generation program, which extracts the optimum configurations of filters shared in hardware through systematic computer calculations, has been developed. A single-chip display processor is now capable of picture-rate conversion processing including block-raster conversions, three types of scan-format conversions, colorinterpolation, edge-enhancement, and inversematrix conversion, and has an internal threechannel D/A converter. Fig. 5 is the block diagram of this processor. Table 2 gives the chip specifications, and Fig. 6 is a photomicrograph of the display processor, an 0.5m CMOS two-layer metal device integrating 1.9 million transistors and measuring 14.9 x 14.9mm2. Total integrated memory is 284kB, and there are a total of 188 filter taps, including those for edge enhancement, etc. By developing chipsets that integrate the key functions required for digital TV transmission and reception, Mitsubishi Electric is laying the foundation for new generations of equipment that will bring digital TV to its huge potential audience, quickly and at minimum cost. u

References: see page 28.

Sync. Data

Pict. Rate conv.

Scan format conv.
Pict. making Color interpolation Enhancement Inverse matrix Error concealment

3ch DAC

Analog RGB

Status decoder

Sync. generator
Fig. 5 Display processor block diagram.
Data Broadcasting Service
by Yukio Yokoyama and Heikan Izumi*
With the emergence of digital television broadcasts, and as channels proliferate and the affinity between television and computers grows, more sophisticated and attractive data-broadcasting services are expected. This article addresses the contents of electronic programs conforming to the U.S. advanced television systems committee (ATSC) standards and related data-broadcasting services, and gives a brief overview of Mitsubishi Electrics system for data-broadcasting services. The SI/EPG System In the system information/electronic program guide (SI/EPG) system, channel and program information are broadcast together with the program contents, so that users can view program
guides on their TV screens and make program selections. Mitsubishi Electric has developed for the U.S. DTV market an SI/EPG system that enables SI/EPG data to be edited on a personal computer for output to a program multiplexer we have produced (Fig. 1). The SI/EPG system is intimately related to the stations MPEG encoder equipment, program multiplexer, broadcasting scheduler and other equipment. It consists of the following three devices: The SI/EPG editor receives program information from the stations broadcasting scheduler and from other stations, and other SI/EPG information necessary for digital TV is added or edited.

and transfers it to the program multiplexer according to the broadcasting schedule. Databroadcasting protocols currently supported are the data-carousel protocol, used for periodic rebroadcasting, and multiprotocol encapsulation, used when attaching IP packets or other data units. The data monitor is located within the station, and is used to verify the contents of data broadcasts. Digital broadcasting, and the new standards being developed for it, support the integration of TV and a wide range of information services. Mitsubishi Electric is commited to developing the systems and hardware to implement these promising new services. u
References (continued from page 26) [1] ISO-IEC/JTC1 SC29, DIS 13818, Part 2, 1994. [2] A. Hanami, S. Scotzniovsky, K. Ishihara, T. Matsumura, S. Takeuchi, H. Ohkuma, K. Nishigaki, H. Suzuki, M. Kazayama, T. Yoshida, K. Tsuchihashi, A 165-GOPS Motion Estimation Processor with Adaptive Dual-Array Architecture for High Quality Video-Encoding Application, Proc. IEEE CICC, 9.1.1-9.1.4, 1998. [3] T. Yoshida, Y. Shimazu, A. Yamada, E. Holmann, K. Nakakimura, H. Takata, M. Kitao, T. Kishi, H. Kobayashi, M. Sato, A. Mohri, K. Suzuki, Y. Ajioka, K. Higashitani, A 2V 250MHz Multimedia Processor, Proc. IEEE ISSCC, pp. 266-267, Feb., 1997. [4] FCC ATSC: FINAL TECHNICAL REPORT, Oct. 31, 1995.
MITSUBISHI ELECTRIC OVERSEAS NETWORK (Abridged)

Country

U.S.A.

Address

Mitsubishi Electric America, Inc. Mitsubishi Electric America, Inc. Sunnyvale Office Mitsubishi Electronics America, Inc. Mitsubishi Consumer Electronics America, Inc. Mitsubishi Semiconductor America, Inc. Mitsubishi Electric Power Products Inc. Mitsubishi Electric Automotive America, Inc. Astronet Corporation Powerex, Inc. Mitsubishi Electric Information Technology Center America , Inc. Mitsubishi Electric Sales Canada Inc. Melco de Mexico S.A. de C.V. Melco do Brazil, Com. e Rep. Ltda. Melco-TEC Rep. Com. e Assessoria Tecnica Ltda. Melco Argentina S.A. Melco de Colombia Ltda. Mitsubishi Electric U.K. Ltd. Livingston Factory Apricot Computers Ltd. Mitsubishi Electric Europe B.V. Corporate Office Mitsubishi Electric France S.A. Bretagne Factory 5665 Plaza Drive, P.O. Box 6007, Cypress, California 90630-East Arques Avenue, Sunnyvale, California Plaza Drive, P.O. Box 6007, Cypress, California 90630-0007 9351, Jeronimo Road, Irvine, California 92618 Three Diamond Lane, Durham, North Carolina Keystone Drive, Warrendale, Pennsylvania Bethany Road, Mason, Ohio Crestwood Parkway Suite 400 Duluth, Georgia 30096 Hills Street, Youngwood, Pennsylvania Broadway, Cambridge, Massachusetts 14th Avenue, Markham, Ontario L3R 0J2 Mariano Escobedo No. 69,Tlalnepantla, Edo. de Mexico Apartado Postal No.417, Tlalnepantla Av. Rio Branco, 123, S/1504-Centro, Rio de Janeiro, RJ CEP 20040-005 Av. Rio Branco, 123, S/1507, Rio de Janeiro, RJ CEP 20040-005 Florida 890-20-Piso, Buenos Aires Calle 35 No. 7-25, P.12 A. A. 29653 Santafe de Bogota, D.C. Houston Industrial Estate, Livingston, West Lothian, EH54 5DJ, Scotland 3500 Parkside, Birmingham Business Park, Birmingham, B37 7YS, England Centre Point (18th Floor), 103 New Oxford Street, London, WC1A 1EB Le Piquet 35370, Etrelles 3rd Floor, Parnassustoren, Locatellikade 1, 1076 AZ, Amsterdam Avenue Louise 125, Box 6, 1050 Brussels Gothaer Strasse 8, 40880 Ratingen Konrad-Zuse-Strasse 1, D-52477 Alsdorf Polgono Industrial Can Mag, Calle Joan Buscall 2-4, Apartado de Correos 420, 08190 Sant Cugat del Valls, Barcelona Centro Direzionale Colleoni, Palazzo Persero-Ingresso 2, Via Paracelso 12, 20041 Agrate Brianza Room No. 1609 Scite Building (Noble Tower), Jianguo Menwai Street, Beijing 39th Floor, Shanghai Senmao International Building, 101, Yincheng Road (E), Pudong New Area, Shanghai Room No. 1221-4, Garden Tower, Garden Hotel, 368, Huanshi Dong Lu, Guangzhou 811 Jiang Chuan Road, Minhang, Shanghai 41st Floor, Manulife Tower, 169 Electric Road, North Point 10th Floor, Manulife Tower, 169 Electric Road, North Point 32nd Floor, Manulife Tower, 169 Electric Road, North Point 410, Dangjung-Dong, Kunpo, Kyunggi-Do 11th Floor, 88 Sec. 6, Chung Shan N. Road, Taipei 75, Sec. 6, Chung Shan N. Road, Taipei Chung-Ling Bldg., No. 363, Sec. 2, Fu-Hsing S. Road, Taipei 152, Beach Road, #11-06/08, Gateway East, Singapore 189721 307, Alexandra Road, #05-01/02, Mitsubishi Electric Building, Singapore 159943 3000, Marsiling Road, Singapore 739108 307, Alexandra Road, #02-02, Mitsubishi Electric Building, Singapore 159943 Plo 32, Kawasan Perindustrian Senai, 81400 Senai, Johor Daruel Takzim No.6 Jalan 13/6, P.O. Box 1036, 46860 Petaling Jaya, Selangor, Daruel Ehsan No. 14 Jalan 19/1, 46300 Petaling Jaya Selongar Daruel Ehsam 28 Krungthep Kreetha Road, Huamark, Bangkapi, Bangkok Moo 11, Bangna-Trad Road KM. 20, Bangplee, Samutprakarn Moo 4, Bangna-Trad Road KM. 23, Bangsaothong, Samutprakarn 10540 700/86~92, Amata Nakorn Industrial Estate Park2, Moo 6, Bangna-Trad Road, Tambon Don Hua Roh, Muang District, Chonburi 17th Floor, Bangna Tower, 2/3 Moo 14, Bangna-Trad Highway 6.5 Km, Bangkawe, Bang Plee, Samutprakarn 10540 K.m. 23 West Service Road, South Superhighway, Cupang, Muntinlupa, Metro Manila 348 Victoria Road, Rydalmere, N.S.W. Parliament St., Lower Hutt, Wellington