One glimpse of high-definition television and you're hooked. You simply have to stop for a closer look. Of all the exhibits at the ``Cable 88'' convention this month, high-definition television, or HDTV, was the thing to see. On conventional TV, a program about microscopic pond organisms could be a real yawner.
But on high-definition TV, it's a drama of astonishing delicacy. The creatures' transparent membranes and hairlike flagella stand out with almost touchable clarity. Their minute movements are captured in crisp detail.
Part of the allure of HDTV is what's not there: no flicker, no visible scan lines, no ``chroma crawl.'' During a slow scene, images have the undisturbed stillness of a photograph, and when the on-screen action gets intense, it flows smoothly without blurring.
HDTV works by packing twice as much information into each image. On conventional TV in the United States, the picture is made up of 525 horizontal lines. HDTV has roughly double that number, on a wider screen that is closer to the shape of a movie screen. The sound is better, too.
Broadcasters and TV manufacturers around the world have been developing high-definition technology for years - the Japanese with particular aggressiveness. The first HDTV sets are expected to reach the US market sometime in 1991 and will cost about $3,500.
But before HDTV programs can be broadcast here, there are knotty technical and political issues to be resolved.
The biggest is, how do you broadcast HDTV programs without making ordinary televisions obsolete? The HDTV system closest to being ready for the market requires signals that cannot be received by today's TV sets.
Japan and Europe are planning to broadcast these signals by satellite. Japan's national broadcasting network, NHK, is already gearing up to try a satellite transmission of the summer Olympics in Seoul to HDTV sets in Japan.
But in the US, the Federal Communications Commission would not approve any system that bypasses conventional broadcasters, because its superior quality could eventually put them out of business, says Lynn McReynolds of the National Cable Television Association (NCTA). High-definition broadcasting by satellite would be a pay-TV service available only to subscribers with a satellite dish.
``The whole government regulation of television over the years has been based on the premise that there should be free over-the-air broadcasting,'' she explains.
So the quest is on for a high-definition system compatible with conventional TV. Philips Corporation, Faroudja Laboratories Inc., the David Sarnoff Research Center, and other companies are working on such systems.
But it's a tough task. HDTV transmission needs more ``bandwidth,'' or room on the frequency spectrum, than regular TV does. To be workable, a system must shoehorn as much information as possible into the already crowded airwaves without causing interference.
The FCC has appointed an advisory panel to study the problem. The panel is completing an interim report this week, but there is much to be done before the commission decides exactly what form HDTV will take in this country. The panel is planning to spend the next year and a half testing systems and developing proposed standards.
Once the standards for HDTV are decided on and the new television sets hit the market, consumers looking to get the most out of their equipment may find cable TV particularly attractive.
``With a cable, you're receiving a picture through a wire that doesn't get the normal interference that a broadcasting signal does. So we think we will be at an advantage,'' says James Boyle of the NCTA.