In a predawn test coinciding with the 50th anniversary of TV's debut at the New York World's Fair, NBC on Thursday transmitted what it called the first commercial broadcast of a high-definition TV signal in the United States.
Mike J. Sherlock, president of NBC Operations and Technical Services, said the broadcast "is to television what Kitty Hawk was to flight." But it made no difference in the picture that television viewers saw here.
That's because TV sets capable of receiving what NBC called the Advanced Compatible Television Signal, which has double the 525 lines of conventional TV sets, are several years away from production. Existing TV sets can receive the high-tech signal but only display a standard picture.
The test transmissions were conducted by the David Sarnoff Research Center in Princeton, N.J., which has been working on ways of improving TV-picture quality for six years. The research has been funded with $60 million by a consortium that includes NBC.
Sherlock said other developments in the ACTV system will be demonstrated on April 29 at the National Assn. of Broadcasters' convention in Las Vegas.
High-definition television already is a reality in Japan, although only on a limited basis, with the higher-quality HDTV signal beamed via satellite to a relatively small number of homes equipped with special receivers.
Regular HDTV broadcasts are to begin in Japan next year, Sherlock said.