The controversy over which high definition television system will be the system of choice for the United States has manufacturers from all over the world vying for dominance.

Although the broadcasters, cablecasters and manufacturers are still far from making a decision about HDTV, the Federal Communications Commission has ruled the new format must be compatible with existing American televisions, eliminating a clearly superior Japanese system now used in that country.An article in the current issue of Video Magazine explores what each competing system has to offer and what the final decision will mean to American consumers.

High definition television is a broadcast and reception standard that allows up to five times more visual detail than is now available on broadcast TV. The result is a sharper picture, improved color, a wide screen shape and digital audio for improved sound.

The best high definition video picture seen to date is the HDTV production standard developed by the Japanese Broadcasting Co., NHK. Designed to take advantage of the way the human eye sees, the NHK system is close to becoming a world production standard and is already used in studios in the United States, Europe and Japan to produce high definition programming. The FCC's guidelines have eliminated those systems, including NHK's and one used in Europe, that do not use the broadcast spectrum efficiently. This has sent researchers scrambling to introduce new systems that meet the FCC's criteria.

A leading contender has been developed by the David Sarnoff Research Center working with RCA and NBC. It is fully compatible with the existing American standard but, like most competing systems, would require new television sets to take full advantage of the benefits of HDTV.