© 2001 A. Michael Noll
All rights reserved.
August 2, 2001
[This material is expanded from a live radio interview on August 2, 2001 from 7:20 to 7:35 AM on FM radio station KPFK in North Hollywood, CA.]
The first regularly scheduled television broadcasting in the United States began in 1939 by NBC in three cities. The FCC (Federal Communications Commission) allocated 13 channels for television broadcasting in 1945, which is the generally accepted date for the beginning of commercial television in the United States. In 1952, the FCC allocated additional radio spectrum for television in the UHF band. The NTSC color television standard was adopted by the FCC in 1953.
Television broadcasting in the United States uses 525 interlaced scan lines, although an industrial standard of 1000 lines was also used in limited cases for closes-circuit television applications. High definition television (HDTV) for the home generally means about 1000 scan lines, which is double the current NTSC analog standard. However, the 525-line standard was chosen based on the acuity of human vision at a specified distance from the screen. HDTV will look better only is the screen is substantially larger and is viewed from a closer distance.
HDTV broadcasting to the home was introduced in Japan by the Japanese Broadcasting Corporation (NHK) with the MUSE system. MUSE is an analog system using compression of the TV signal. Both CBS and RCA developed analog HDTV systems in the 1980s that were backwards compatible with the existing NTSC system. The TV industry than made the decision to leapfrog over analog and develop digital television. One reason was to stimulate television manufacturing in the United States and forestall Japanese domination. A Grand Alliance was formed within the television industry to agree upon a standard and to promote HDTV. The industry then lobbied the Congress and the FCC for legislation and rules to foster HDTV on the public, supposedly for the benefit of the television broadcasters and set manufactures.
The Telecommunications Act of 1996 authorized the FCC to issue "...additional licenses for advanced television services..." on designated frequencies to the existing broadcasters. At some time in the future, "...either the additional license or the original license [would] ...be surrendered..."
The FCC Fifth Report and Order (adopted April 3, 1997) set the rules for advanced television services as legislated by the Telecommunications Act. The FCC Order called digital television "a technological breakthrough" and reaffirmed the national policy to "...preserve and promote universal, free, over-the-air television." The FCC considered a schedule of 15 years for adoption of a digital TV system, but decided on a more ambitious target date of 2006 for ceasing the broadcasting of analog television. The target date is subject to review every two years. A variety of objective standards for determining when to surrender one of the licenses is discussed in the FCC Order, such as the percentage of digital sets sold or the percentage of TV households relying on digital television.
Digital is a form of encoding in which the waveform of a signal is represented as a series of digits, which are then encoded as binary "0s" and "1s," or as "ONs" and OFFs." Since digits rather than an analog of the waveform are encoded, the digital representation allows near perfect storage and transmission. But these advantages are obtained at the expense of bandwidth, and digital requires considerably more bandwidth than analog. The solution is to compress the digital signal. For television, this compression is accomplished using the MPEG (Motion Pictures Expert Group) standard. VCR quality is possible at about 1 Mbps. DVD quality is possible at from 2 to 4 Mbps.
Digital TV has many possible meanings. It can mean HDTV. But HDTV involves many factors, such as an increase in the number of scan lines (to about 1000), a wide screen display, non-interlaced scanning with less flicker, and compression of the digital signal to conserve bandwidth when transmitted. Digital TV can also mean multicasting in which a number of conventional (but digitized) TV signals are sent in the space of a single channel. The multiple signals (usually about four) can be time-displaced versions of the same program, multiple different programs, or different camera shots of the same program. Digital TV can also mean some yet-undefined form of interactive television.
The many different meanings of digital TV can be confusing to consumers. Confused consumers usually do not buy and instead walk away. The definitions are also different for different segments of the television industry, depending on the advocacy of the segment at the present time. This only compounds the confusion as we wait for the dust to settle.
Since my old television set is either on of off, I have jokingly referred to it as a digital TV set. This little play on words is one way to determine whether my audience has fallen asleep!
Consumers watch television because of program content-not picture quality. Thus, HDTV might only allow consumers to see more clearly how poor the program content is!
In the end, digital television is all about radio spectrum space. Radio spectrum space is a very valuable commodity. Once a chunk of it has been allocated in some geographic region, it can not be used for other purposes. Whomever obtains a license to its use, in effect, "owns" valuable radio spectrum property.
Radio waves travel over distance and reach use wherever we might be. Radio waves were first observed by Thomas Alva Edison in 1875. Radio waves were first used for wireless telegraphy and then for broadcasting of music and news. Guglielmo Marconi sent the first radio waves across the Atlantic Ocean in 1901. Nikola Tesla envisioned radio as a mass medium for broadcasting. Edwin Howard Armstrong developed essential electronic circuitry and championed FM radio broadcasting. Today, radio waves are used for commercial AM and FM radio broadcasting, for VHF and UHF television broadcasting, for wireless cellular telecommunication, for communication satellites, and for a host of other applications. Each application utilized its own unique band of radio frequencies within the radio spectrum.
Each television station in the United States broadcasts within a band of electromagnetic radio spectrum that is 6 MHz (6,000,000 Hertz) wide. For digital television broadcasting, the FCC gave each broadcaster an additional 6 MHz in the UHF band. Thus, each television broadcaster now controls 12 MHz of spectrum space. One of the channels is to be returned someday in the future, but "someday" has a way of becoming forever. If spectrum were abundant, the hogging of 12 MHz by each television broadcaster would not be a problem, but radio spectrum is a scarce commodity.
Radio should be used for valuable, needed services that can not be delivered by other media. Wireless cellular telecommunication reaches us anyplace, anytime, anywhere. Radio is the only way such telecommunication can occur. The tremendous growth of wireless cellular service has created great demands for additional radio spectrum space. The frequencies that would be most useful are in the UHF band that is currently being allocated for digital television. Thus, the television broadcasters and the wireless telecommunication providers are headed for a clash over this valuable spectrum space.
The television broadcasters were given licenses for the additional 6 MHz for free. Wireless cellular providers are charged by the government for their spectrum space through an auction process. Thus, digital television has become the biggest give-away ever to a privileged industry. Television broadcasters has considerable political influence and usually get their way-and for free!
Today's television broadcasters are a few megaliths. CBS is owned by Viacom; NBC by General Electric; ABC by Disney; and everything else by Murdoch and Warner. It is difficult to justify the giving of valuable spectrum space to such huge and wealthy firms.
In 1945 when television first began broadcasting over the current VHF channels, 100 percent of TV households obtained their television over-the-air. There were no alternatives. Today, television is obtained over a variety of media: over-the-air VHF and UHF broadcasts, cable (CATV) television, direct broadcast satellite (DBS), other forms of satellite broadcast, and physical media (such as tape and disc). In 1997, only 22 percent of TV households obtained their television directly over-the-air, and I am told that today that percentage is much less than 20 percent, and continuing to decline. Over-the-air television is dying!
The people who still obtain their television directly over-the-air are most likely the poor and those too cheap to pay for cable or DBS. These are not the kinds of consumers who will lead the pack by investing in new digital television sets. There thus is no market for over-the-air digital television. The times have changed. It is no surprise that the broadcasters are now delaying their plans for over-the-air digital television.
Although over-the-air digital television might have a dismal future, digital television is already here in many ways and forms. Direct broadcast satellite television is sent digitally using compression, and some DBS systems are already offering HDTV on some of their channels. The digital video disc (DVD) is digital and has images with tremendous technical quality. Television studios are using digital to process and store television programs which are then sent in analog form over-the-air. Cable systems are starting to convert to digital transmission, although the cost is high because of the need for new set-top boxes.
The world of television has changed from the late 1980s when HDTV was hatched. The market for over-the-air digital television has evaporated, and perhaps really was little more than the result of fuzzy thinking and over promotion. Today is a time when most people in the United States obtain their television over cable, when satellite dishes are appearing on the roofs of homes around the country, and when almost everyone has a DVD player. This is a new world of television, and over-the-air television has been left behind.
What then should be done? There will always be a few consumers for whom over-the-air, free broadcasting is their only source of television. But radio spectrum is too precious to allocate 6 MHz per television channel to serve this dwindling audience. One solution would be to require cable companies to offer free basic cable service. Another solution would be to require television broadcasters to compress their television signal to 1 MHz using digital technology and then provide inexpensive converters to those who watch over-the-air television.
The future and ultimate fate of over-the-air television is a matter of public debate that will require careful thought by the FCC and by political leaders.
Noll, A. Michael, Television Technology: Fundamentals and Future Prospects, Artech House, Inc. (Norwood, MA), 1988.
Noll, A. Michael, "High Definition Television (HDTV)," Chapter 57 in Media USA (Second Edition), Arthur Asa Berger (Editor), Longman: New York (1991), pp. 431-438.
Noll, A. Michael, Highway of Dreams: A Critical Appraisal of the Communication Superhighway, Lawrence Erlbaum Associates (Mahwah, NJ), 1997.
Noll, A. Michael, "Digital Television, Analog Consumers," Telecommunications, Vol. 31, No. 9, September 1997, p. 18.
Noll, A. Michael, "The Evolution of Television Technology," in Darcy Gerbarg (Ed.), The Economics, Technology and Content of Digital TV, Kluwer Academic Publishers (Boston), 1999, pp. 3-17.
Noll, A. Michael, "The Impending Death of Over-the-Air Television, info, Vol. 1, No. 5 (October 1999), pp. 389-391.
Noll, A. Michael, Principles of Modern Communications Technology, Artech House, Inc. (Norwood, MA), 2001.