WASHINGTON -- The three top rivals for the right to develop the next generation of television technology in the United States agreed yesterday to join forces on a single approach, hastening the biggest change in broadcasting since the advent of color in the 1960s.
The agreement to collaborate on high-definition television, a move strongly supported by top federal officials, eliminates the likelihood of protracted disputes and litigation, which could have delayed the introduction of the technology for years.
With yesterday's agreement, HDTV -- offering wide-screen pictures nearly as bright and clear as movies and sound approaching the crispness of digital compact disks -- could be available as early as 1995.
The agreement to collaborate also represents a broad technical consensus for the next generation of television sets. The industry has paved the way for television's rapid convergence with the interactive world of computers and high-speed two-way communications.
The new HDTV system will be digital, meaning the signals will be transmitted in the ones and zeros of computer code, instead of the traditional, less precise, technique of transmitting television signals in electromagnetic waves that mimic sound and light waves.
"This is not just about pretty pictures," said Richard E. Wiley, chairman of the federal advisory committee for HDTV. "We are looking for interoperability -- not only between broadcasting and cable, but also with computers. This has applications in factory automation, medical imaging and even defense."
The alliance effectively ends a remarkable competition begun nearly five years ago when the Federal Communications Commission announced its intention to choose a standard for advanced television and invited companies from around the world to propose systems.
The three groups that joined forces yesterday were the sole survivors of a rigorous testing process that began in 1991 and ended thisFebruary. One of the three is a team consisting of General Instrument Corp. and Massachusetts Institute of Technology. A second team is Zenith Electronics and American Telephone & Telegraph Co. The third group is a consortium formed by Philips Electronics of the Netherlands, Thomson Consumer Electronics of France, NBC and the David Sarnoff Research Center in Princeton, N.J.
The new alliance hopes to develop a working model in as few as nine months. The new system would then require testing and approval by the FCC, which hopes to adopt a new standard sometime next year.
Under rules the commission adopted last year, television stations will be given a second channel for HDTV. Each station would be required to begin transmitting HDTV signals within five years of the adoption of the standard.
Television sets capable of receiving HDTV signals could be available as early as 1995. To receive these signals, consumers will need special sets expected to initially cost $1,000 to $2,000 more than today's sets. But broadcasters will also continue to transmit programs in the traditional format into the next century.
In an attempt to broker the competing demands of broadcasters and computer companies, the alliance has agreed that the system will be capable of transmitting images in a number of different formats with varying degrees of sharpness.
This decision means that movie spectaculars might be transmitted in the most sophisticated format, for example, while news programs could be transmitted at lower resolution and at less cost to the broadcaster. Each household's television set would decode the signals according to electronic instructions that accompany them.
The system tries to satisfy the demands of computer companies, which have argued that the next generation of TV sets have to display images without the flickering that is characteristic of most video systems.
Perhaps the most important feature of the new system will be that it transmits images and sound entirely in digital form, a concept that most broadcasting experts ridiculed as impossible and impractical as recently as 1990. The HDTV format already used in Japan and under development in Europe transmits programs in the traditional analog form, in which electromagnetic waves are analogous to the original images.
Digital broadcasting offers much greater freedom from distortion and static. More important, a television system that uses digital transmission handles information in the same way as a computer and can be used to provide a rich array of interactive services like games, shopping and browsing through electronic libraries.