Japan's NHK tests long-distance 8K TV broadcast signal

Successful 27-kilometer test is aimed at bringing 8K to viewers ahead of the 2020 Olympics.

Japan's public broadcaster has successfully broadcast long-distance digital terrestrial signals for its Super Hi-Vision 8K format, sending massive amounts of data over UHF airwaves, but despite this test it's unclear if many Japanese will be watching 8K TV by the time Tokyo hosts the Olympics in 2020.

Nippon Hoso Kyokai (NHK) Science & Technology Research Laboratories conducted the test from its bureau in Hitoyoshi, Kumamoto Prefecture, in southern Japan, and managed to send the 8K Ultra High Definition TV signal to a receiving station 27 kilometers away using a single UHF channel.

"The success of this experiment is a big step forward toward the realization of 8K Super Hi-Vision terrestrial broadcasting," NHK Labs researcher Tomohiro Saito said. "We're now working on overcoming one challenge at a time to implement it."

In May 2012, NHK's sent the world's first successful terrestrial signal in 8K to a point 4.2 km away. The broadcaster has been recording sports and other events in 8K with the aim of allowing households to receive the high-res signals in the future.

At 7,680 pixels by 4,320 pixels, about the equivalent of a 32-megapixel photo, the resolution of Super Hi-Vision is 16 times that of standard HD and four times that of 4K TVs. It also has a 22.2 multichannel sound system.

It's seen as the next step beyond 4K, which has been prominently featured at the Consumer Electronics Show in Las Vegas in recent years. About 500,000 4K TVs are expected to sell in the U.S. in 2014, according to the Consumer Electronics Association (CEA).

Uncompressed Super Hi-Vision signals can run about 24 gigabits per second or even 48 gigabits per second at 120 frames per second. NHK researchers have used orthogonal frequency-division multiplexing (OFDM), a digital data encoding method used in Wi-Fi, as well as multiple-input, multiple-output (MIMO), a technique in which multiple antennas are used at the points of transmission and reception to enhance performance.

"NHK's successful 8K trial has demonstrated technical feasibility," said Damian Thong, a technology analyst at Macquarie Securities in Tokyo. "This was never really in doubt given the technological capability of the NHK and its partners."

"The real question is whether there will be a commercial argument for 8K adoption just based on resolution," Thong added. "Simply, for most typical television viewing distances, normal humans may not be able to discern the difference between 8K and 4K. The more compelling argument for migration may be in other aspects of picture quality that will also improve with the migrations to 4K and beyond, including frame rate, color, and dynamic range.

"The move to 4K and 8K will be costly for broadcasters and other content providers. As it stands, the 4K migration will run into early next decade as there will be some initial conservatism all round. After that there will be a period, probably lengthy, when the focus will be on making investments pay off.

"So I do not expect 8K to be mainstream, if at all, till perhaps 2030 or so," Thong concluded.

NHK is funded by the Japanese government and fees paid by TV users in Japan. It has been researching high definition or what it calls Hi-Vision television since 1964, recording the Los Angeles Olympic Games in the format 20 years later.

It began research into Super Hi-Vision in 1995, and in 2012, the broadcaster produced six channels of live 8K video of the London Olympics for public viewing at sites in the U.K., the U.S., and in Japan. It said the 8K video made audiences feel as if they were at the Olympic events themselves.

Following the 2012 Games, the U.N. International Telecommunication Union approved 8K as a new high-resolution TV format. NHK has since shown 8K content at the Cannes Film Festival and the Tokyo International Film Festival.

It also plans to tape next month's Sochi Olympics in Super Hi-Vision and show the video at public viewing locations in Japan including Tokyo and Nagoya.

Looking ahead, NHK is slated to begin test satellite broadcasts in Super Hi-Vision for the Rio de Janeiro Olympics in 2016, and what is says will be "full broadcasts" in 2020, when Tokyo will host the summer Olympics.

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