Improvements in Television Technology

views updated

Improvements in Television Technology

Although television sets first became available to the American people in the late 1930s, sales did not really begin to take off until after World War II ended in 1945. The following year, industry leader RCA (Radio Corporation of America) introduced the 630-TS set, a black-and-white model with a ten-inch screen. RCA sold ten thousand units in the first year, at a price of $385 each. In 1947 sales jumped to two hundred thousand units. In fact, the 630-TS became so popular that it was often referred to as the "Model T" of television (after the hugely successful early Ford automobile, which brought car ownership to many people).

The American television industry grew rapidly during the postwar years. TV ownership increased from 10 percent of American homes in 1950 to 67 percent in 1955, then reached 87 percent in 1960 and 94 percent in 1965. The number of commercial television stations grew rapidly as well—from nine immediately after the war ended in 1945 to five hundred by 1960. Continuing improvements in television technology—including the development of color TV, the use of satellite transmission systems, the invention of videotape technology, and the introduction of high-definition TV—helped fuel this remarkable growth.

Color TV makes its debut

After electronic systems overtook mechanical systems to become the television technology of choice, the next major technical challenge involved developing color TV sets. The Scottish inventor John Logie Baird (1888–1946) demonstrated the first color television as early as 1928. His mechanical system used a spinning disk with three colored filters on it. The disk rotated behind the TV screen, and the filters corresponded with special gas-filled cells that lit up to provide colors for viewers. The following year, Bell Laboratories, a communications research company, demonstrated the first color television system in the United States. Like Baird's invention, it was a mechanical system that displayed a crude image on a screen the size of a postage stamp.

The first real breakthrough in color television technology took place shortly before the United States entered World War II (1939–45) in 1941. The main figure behind the development of color TV was Peter Gold-mark (1906–1977), an engineer who worked for the Columbia Broadcasting System (CBS). CBS had been created in 1927 through the merger of two entertainment companies. Under the leadership of William S. Paley (1901–1990), CBS grew into a strong radio network by the mid-1930s. Around this time, Goldmark talked Paley into starting a small research department at CBS to focus on the emerging technology of television.

Goldmark first became interested in adding color to television in early 1940, when he saw the blockbuster movie Gone with the Wind. "For me it was a uniquely exhilarating experience, not because of the performers or the story, but because it was the first color movie I had seen, and the color was magnificent," he recalled in Tube: The Invention of Television. "I could hardly think of going back to the phosphor images of regular black-and-white television. All through the long, four-hour movie I was obsessed with the thought of applying color to television."

Upon returning to his lab at CBS, Goldmark spent the next six months working feverishly to develop a color television system. The method he came up with became known as a "field-sequential" color system. It involved two spinning wheels with red, blue, and green filters—one behind the lens of a TV camera and one in front of the cathode ray tube inside a TV set. The spinning wheel in the camera scanned the image in color, and the spinning wheel in the receiver reproduced the colors in sequence as they appeared in the original scene. In effect, the color TV set painted a black-and-white image in three colors in rapid succession. Goldmark's color system was a combination of mechanical and electronic TV systems because it used a mechanical spinning wheel to insert color into an electronic television system.

Goldmark had perfected his color television system by August 1940. That month, CBS sent him as a representative to the National Television System Committee (NTSC). This group of scientists and engineers studied television technology and made recommendations to help the Federal Communications Commission (FCC) establish national standards. (The FCC, a government agency, was created in 1934 to oversee and regulate all types of communications, including radio, television, telephone, and telegraph.) Since black-and-white electronic television systems had recently been perfected, the FCC was eager to set rules to guide manufacturers and broadcasters.

As the NTSC debated the benefits of various black-and-white systems, Goldmark got upset. He believed that his color television system was far superior to any existing black-and-white technology, so he felt it was pointless to spend a lot of time discussing black-and-white TV standards. He finally stood up and told the group that he had perfected color television broadcasting. "I calmly announced that we could transmit pictures in color, and I invited the assemblage to a demonstration in the CBS laboratory of a broadcast from the Chrysler Building [in New York City]," Goldmark remembered in his book Maverick Inventor: My Turbulent Years at CBS. NTSC attendees were eager to see Goldmark's technology.

Goldmark's demonstration impressed representatives of the FCC. According to Tube: The Invention of Television, seeing the CBS color system prompted FCC Chairman Lawrence Fly to rethink issuing black-and-white standards. "If we can start television off as a color proposition, instead of a black-and-white show, it will have a greater acceptance with the public," he declared. Although the FCC recognized the potential benefits of the CBS system, it ultimately decided that color television required further testing. When the FCC issued its first technical standards for commercial television broadcasting in April 1941, the rules only addressed black-and-white television systems. The FCC did allow CBS to begin experimental color broadcasts, but further development of the technology was suspended during World War II.

A "color war" pits RCA against CBS

David Sarnoff (1891–1971), the powerful president of RCA, had watched the development and testing of Goldmark's color television system with great interest. RCA had invested a great deal of time and money in developing black-and-white television systems and taking control of TV manufacturing. As soon as the ban on TV manufacturing was lifted following World War II, RCA emerged as the leading producer of black-and-white television sets in the United States. In fact, the company controlled 80 percent of the market. Sarnoff realized that his company stood to lose a fortune in sales if the FCC approved the CBS color system for commercial production.

In 1946 CBS invited FCC representatives to a formal demonstration of the Goldmark color system and once again asked for it to be adopted as a commercial standard. The new FCC chairman, Charles Denny, initially seemed as impressed with the system as Lawrence Fly had been in 1940. But Sarnoff and RCA immediately began working to turn the FCC and the public against the CBS color television system. Sarnoff argued that Goldmark's system relied upon lesser quality mechanical technology that RCA and other TV manufacturers had discarded years earlier. According to Kenneth Bilby in The General: David Sarnoff and the Rise of the Communications Industry, Sarnoff claimed that adopting the CBS system as a technical standard would "set back the cause of our technology by a generation." He also declared that "RCA will never allow this counterfeit scheme [false plan] to be foisted on the American people." Sarnoff requested that the FCC wait until an all-electronic color TV system could be perfected before adopting a color standard.

As sales of RCA's black-and-white TV sets grew rapidly during the postwar years, Sarnoff added another argument against the CBS color system. He pointed out that it was incompatible, or did not work properly, with the growing number of black-and-white sets on the market. He meant that anyone who had already purchased a black-and-white set—and 250,000 people had done so by the end of 1947—would see nothing but static during color broadcasts. Goldmark tried to overcome this argument by creating a converter that could be attached to black-and-white sets to allow them to receive color signals. CBS also took out advertisements telling consumers to wait for color to become available before purchasing a television set.

Due in part to Sarnoff's objections, in 1947 the FCC once again decided to postpone the adoption of a color television standard. The FCC claimed that adopting an incompatible color standard would place an unfair burden on the growing number of consumers who had already purchased black-and-white TV sets. If they wanted to receive color broadcasts on their existing sets, they would have to pay for converter units or expensive modifications. The FCC also claimed that it was trying to protect broadcasters with its decision. If television networks chose to broadcast in color, the FCC commissioners argued, they would lose the portion of the viewing audience that had not yet converted to color receivers. Finally, the FCC noted that RCA and several other competitors were working on experimental electronic color TV systems that would be compatible with existing black-and-white systems.

Goldmark and CBS were understandably upset with the FCC's decision. After all, it allowed RCA to rush ahead with its production of black-and-white sets and thus limit the future market for color televisions. CBS executives became even angrier six months later, when Charles Denny resigned as chairman of the FCC to take a job as vice president and general counsel for NBC, the broadcasting arm of RCA. CBS claimed that Denny's job change indicated that RCA had bribed him in order to gain favorable FCC decisions. But Denny and RCA denied the charges.

CBS wins a temporary victory

In 1949 Goldmark used an American Medical Association conference to demonstrate his color television system to the public. CBS set up a number of TV sets at the convention center in Atlantic City, New Jersey, and broadcast live surgical procedures from a nearby hospital. An estimated fifteen thousand people witnessed the demonstration, and a fair number of them passed out at the sight of the bright red blood. "We began to measure the impact of our television shows by the number of faintings we could count," Goldmark noted in Maverick Inventor. The success of these broadcasts created a growing public demand for access to color television technology. Legislators heard the call and began pressuring the FCC to remove the barriers keeping color TV from the American people.

Later that year, CBS once again petitioned the FCC to adopt its color television system as the technical standard for the United States. To help make its case, CBS arranged for a side-by-side test against RCA's best electronic color system, which was still in development at that time. The CBS system clearly outperformed RCA's system in the test. As cited in Tube: The Invention of Television, even Sarnoff admitted that, with the experimental RCA system, "The monkeys were green, the bananas were blue, and everybody had a good laugh." But Sarnoff claimed that RCA's scientists were on the verge of perfecting electronic color television, and he argued that the mechanical CBS system was inferior technology. "You are being urged to build a highway to accommodate the horse and buggy when already the self-propelled vehicle is in existence," he warned the commission.

Thanks to the test results and the increasing political pressure, however, CBS finally managed to convince the FCC that adopting its color system was in the public interest. The FCC established Goldmark's system as the color standard in 1950 and authorized commercial production of color TV sets to begin immediately. RCA objected to the decision, and appealed it all the way to the U.S. Supreme Court, the highest court in the United States. When the Court upheld the FCC's decision in 1951, it marked an important victory for CBS. "We had taken on the great Sarnoff, the king of Radio City, and won," Goldmark stated in Maverick Inventor.

CBS launched a regular schedule of color broadcasts in June 1951. The first program, called Premiere, featured Ed Sullivan and several other well-known entertainers. Unfortunately for CBS, almost no one saw the show. Of the twelve million TV sets in American homes at that time, only about two dozen could receive color broadcasts. CBS soon found that there was very little it could do about the lack of color TV receivers. CBS had come to prominence as a radio network, and it did not have the capacity to manufacture television sets. To complicate matters, the United States was involved in the Korean War (1950–53) at this time, so most of the nation's manufacturing plants were dedicated to making military equipment. As a result, CBS faced a long and expensive battle to produce a profitable line of color television sets. In October 1951 CBS was forced to discontinue its color broadcasts due to the limited number of viewers who could watch them.

Color TV slowly gains acceptance

In the meantime, Sarnoff became committed to developing a workable electronic color television system. He ordered RCA's engineers to spend as much time and money as necessary to perfect the technology. In 1951, shortly after the Supreme Court ruled in favor of CBS, RCA unveiled the result of this effort: an all-electronic color television system that was compatible with existing black-and-white broadcast standards (see sidebar "Electronic Color TV"). When RCA demonstrated the new system for the media, several reporters expressed the opinion that the FCC had made a terrible mistake by approving the CBS color system. As noted in Tube: The Invention of Television, Jack Gould of the New York Times wrote that RCA's successful development of electronic color TV "put the FCC on a spot which is certain to become controversial and embarrassing."

Both CBS and RCA put the development of color television on hold during the last two years of the Korean War. By the time the war ended in 1953, American consumers had purchased twenty-three million black-and-white TV sets. At this point, CBS gave up trying to manufacture its color system. CBS President William S. Paley decided that the large number of incompatible black-and-white sets in U.S. households would prevent Goldmark's mechanical color system from ever gaining a hold in the market. Later that year, the FCC reversed its earlier decision and established RCA's electronic color system as the commercial standard.

Electronic Color TV

Color television sets function in a very similar way to black-and-white sets, with a few important differences. Instead of a single electron beam within the cathode ray picture tube, for instance, a color TV set has three electron beams—one red, one green, and one blue. These beams move across the inside of the screen at the same time. Instead of a single sheet of phosphor that glows when struck by the electrons, the screen of a color TV set is coated with red, green, and blue phosphors arranged in a pattern of hundreds of thousands of tiny dots. As the three electron beams move across the screen and paint it with an image, the beam of each color strikes the phosphor dots of the same color, causing them to glow. If a portion of the picture was red, for example, then the red beam excites the red phosphor dots in that area of the screen.

The color TV camera also differs from a black-and-white one. When a color TV camera scans an image, it separates the light reflected off that image into its three color components before turning the information into electrical signals. A color TV signal is the same as a black-and-white signal except that it contains an additional element called chrominance. Black-and-white television sets simply ignore this part of the signal, while color TV sets use it to determine how to fire the three colored electron beams at the screen. This feature of electronic color television signals allows them to be viewed on older black-and-white sets, making the two systems compatible, or able to work together properly.

RCA began selling its all-electronic color TV sets to the public in 1954. Sarnoff predicted that sales would reach seventy-five thousand units in the first year, but only a few thousand of the sets actually sold. These figures prompted Time magazine to declare color television a "resounding industrial flop." American consumers were slow to accept color TV technology for a number of reasons. Prices of color sets were significantly higher than black-and-white sets, while the color screens were much smaller. Consumers often found it difficult to adjust the sets for proper color reception, and the sets required more maintenance than the time-tested black-and-white models. In addition, the public found little reason to buy color TV sets because the major broadcast networks did not offer much color programming in the early years. For instance, CBS offered only eight hundred hours of color programming in all of 1965, while ABC provided only six hundred hours.

NBC offered more color programming than the other major networks because it wanted to help its parent company, RCA, sell color TV sets. One of the first hit programs to be broadcast in color was Walt Disney's Wonderful World of Color, which began airing on NBC in 1960. The show's success helped increase demand for color TV sets. After spending $130 million on product development and marketing, RCA announced that it had earned a profit on its color systems for the first time that year. By 1967 most television broadcasts were in color, and by 1972 half of the TV sets in American homes were color.

Improvements in TV transmission systems

Throughout the battle over the development of color television systems, scientists and engineers continued to improve upon broadcast technology. In 1945, for example, the Western Union telegraph company introduced the first experimental microwave relay system. This system consisted of a series of towers that relayed radio wave signals through the air between New York City and Philadelphia, Pennsylvania. Installing towers every few miles to carry broadcast signals cost considerably less than burying miles of coaxial cable to connect distant locations. (Coaxial cable—which consisted of copper wire surrounded by insulation, with an aluminum covering—could be used to transmit TV, telephone, and data signals.) As a result, microwave relay systems quickly grew in popularity, until by the 1970s they were used to carry most television broadcasts.

The birth of cable television

In 1948, as the major broadcast networks were busy starting television stations in large cities across the country, some rural communities began testing cable television. Since the FCC limited the number of television stations it licensed, most stations were concentrated in cities with large populations. This strategy allowed the stations to reach more viewers with their broadcasts and thus attract more money for advertisers. One negative consequence, however, was that the residents of many rural areas did not enjoy good network TV reception. To address this problem the idea arose to run cables from the rural areas to television stations in nearby large cities.

Two of the first communities to test cable television transmission systems were the mountainous cities of Lansford, Pennsylvania, and Astoria, Oregon. Unlike the cable TV systems available in the 2000s, the pioneer cable providers did not offer a wide assortment of different channels. Instead, they mainly re-transmitted signals from the broadcast networks so that rural residents could get better reception. Cable television service grew slowly until the 1960s, when increasing numbers of local providers appeared. In 1960 there were 640 cable TV systems nationwide, with 650,000 subscribers. By 1970 these figures had increased to nearly 2,500 cable systems with 4.5 million subscribers.

The major broadcast networks began pushing the FCC to regulate, or make rules to control, cable television as early as the mid-1950s. At first, however, the commissioners claimed that they did not have the authority to regulate cable systems since the technology did not use the air waves. In 1962, however, the FCC reconsidered and claimed jurisdiction (authority or command) over cable providers. The commissioners decided that they did have the authority to regulate cable TV because it had the capacity to affect broadcast networks.

Satellite broadcasting

Another significant development in the transmission of television signals took place in 1962, with the world's first satellite broadcast of a TV program. Satellites are like giant antennas that orbit around Earth and can be used to relay communications signals. The development of satellite television capability grew out of an agreement between two American communications companies (AT&T and Bell Labs), the National Aeronautics and Space Administration (NASA), the British Post Office, and the French National Post Office. These institutions led an international effort to develop, launch, and transmit signals using telecommunications satellites. The first satellite, called TELSTAR, was launched into orbit around Earth from the Kennedy Space Center. The following day saw the first live television program ever transmitted across the Atlantic Ocean, between Andover, Maryland, and Pleumeur-Bodou, France.

The introduction of satellite technology marked a major development in television history. Satellite transmission made it possible for American TV viewers to see events elsewhere in the world as they occurred. Before this time, it could take days or even weeks for people in the United States to learn about events in distant countries. Some historians claim that satellite transmission of television signals helped increase Americans' understanding of other nations and cultures. It certainly enabled Americans to witness exciting and momentous events in their nation's history as they happened. In 1969, for example, an estimated 600 million people around the world watched live via satellite as American astronaut Neil Armstrong (1930–) became the first human being to set foot upon the Moon.

Fiber-optic cable

Another major development in the delivery of television signals came in 1970, when a group of researchers for the Corning chemical company invented fiber-optic cable. This type of cable consists of clear rods of glass or plastic. They transmit TV signals or other types of information using rapid pulses of light. Fiber-optic cable can carry sixty-five thousand times more information than traditional copper wires. The technology led to significant improvements in the delivery of television programming to American households.

Impact of videotape technology

Meanwhile, the process of creating television programs also changed technologically. In 1956 a company called Ampex introduced the videotape recorder (VTR). Up to this time, most television programs were broadcast live, as they happened. The only way to preserve video images for later viewing was through a process called kinescope recording, in which a special movie camera recorded what was displayed on a television monitor. Kinescopes were a kind of film, and they required several hours to develop. In contrast, the VTR captured live images directly from TV cameras, converted them into electrical signals, and saved them onto reels of magnetic tape. The broadcast industry immediately recognized the VTR as vastly superior to the kinescope film system that had been used to record television programs. Videotape technology also provided much better visual and audio quality on home television sets.

The introduction of videotape also led to a shift in the relationship between broadcast networks and the advertisers who sponsored programs. Before the mid-1950s, the sponsor of a television program usually developed and produced that program. This gave advertisers a great deal of control over the content of TV programming. The sponsor could approve the script, select the actors, and even insert positive messages about its products into the stories.

When sponsors produced programs, they usually were broadcast live from network studios in New York City. Once videotape technology became available, however, television programs could be recorded almost anywhere. Within a few years, most of the artistic and technical parts of the TV industry moved to California in order to take advantage of the film talent and production expertise in Hollywood. The role of corporate sponsors gradually decreased, and the networks gained the power to develop their own programming.

VCRs make their debut

Nearly two decades later, videotape technology once again led to important changes in the television industry. In 1972, the Phillips Corporation introduced the first video cassette recorder (VCR) for TV viewers to use at home. VCRs allowed viewers to record television programs for later viewing. They used magnetic videotape enclosed in a plastic cassette. Competing companies soon offered similar machines that used cassettes of different shapes and sizes. In 1976, for instance, Sony introduced the Betamax format of home VCR. The following year, RCA released its VHS format VCR, which became the standard that is still used in the 2000s.

The earliest VCRs were large, expensive, and the subject of serious debate. In fact, shortly after home videotaping technology became available, several major Hollywood movie studios joined in a lawsuit, or court case, against the companies that manufactured the machines. The studios argued that VCRs should be outlawed because their main purpose was making illegal copies of television shows and movies. The studios felt that people who used home VCRs to tape movies were stealing copyrighted material (a copyright is a form of legal protection for creative works—including books, pictures, music, films, and software—that prevents others from using the works without the creators' permission). The studios worried that widespread use of VCRs would reduce the income they earned from their movies.

The legal dispute over VCRs resulted in Sony Corporation v. Universal City Studios (more commonly known as the Betamax case), which went all the way to the U.S. Supreme Court. In 1984 the Court ruled in favor of Sony, the VCR manufacturer. The justices said that using a VCR to tape a television program or movie did not violate the studios' copyright protection, as long as the tape was intended for personal use at home rather than for commercial (moneymaking) purposes. As soon as it became clear that home VCR use was legal, sales of VCRs increased sharply.

As it turned out, VCRs did not cause harm to the movie industry. In fact, the popularity of home video actually led to an overall increase in income for the movie studios. "The studios have come to enjoy greater revenue from cassette sales and rentals than from theatrical exhibition, and must look back in wonder at their temporary insanity when the player-recorders first were sighted in North America," Michael Couzens explained in the Museum of Broadcast Communications publication Networks.

The impact of home VCR use on the broadcast TV networks has not been as positive as it has been on the movie industry. The most frequent use of the VCR draws viewers away from network television to watch movies that played in theaters. Many people also use their VCRs to record television programs for later viewing. When they watch these programs, however, they often use the VCR's fast-forward feature to skip the commercials. As of the early 2000s, the networks have been allowed to count the viewers who record programs in their audience totals. These figures are used to determine the rates networks can charge companies to advertise on certain programs. The larger the audience for a program, the higher the rates a network can charge for commercial time during that program. If studies continue to show that VCR users bypass commercials, however, advertisers may demand changes in the way audience numbers are calculated.

Improvements in picture and sound quality

By the turn of the twenty-first century, most television sets still worked on the same principles as the original sets that were invented in the 1930s. As described in Tube, both early and modern television systems "scan an image with a beam of electrons to create an electrical signal, and then re-create the image at the receiver by turning that signal back into an electron beam and bombarding a fluorescent screen." Despite using the same basic technology, however, television sets still underwent a number of technical improvements over the years. For instance, the first wireless TV remote control, a device that allows viewers to change channels from their seats, was introduced by Zenith in 1957. This futuristic technology, called the Space Commander, represented a vast improvement over earlier models, which were connected to the TV set by wires and did not function properly in direct sunlight.

The audio portion of television systems also improved over the years. The FCC authorized multichannel TV sound broadcasts for the first time in 1984. This meant that broadcasters could separate the sound portion of programs into different audio signals to create a more natural listening experience for people at home. Almost immediately afterward, new TV sets flooded into appliance stores offering stereophonic sound. Better known as stereo, this technology reproduced sound using two independent audio channels, which gave viewers the impression that the sounds on television programs came from various directions. The national television networks began broadcasting in stereo at this time, and within two years stereo TV broadcasts were available in all major U.S. population areas. In 1987, television sound improved further with the introduction of the Dolby noise reduction system for TV sets. This technology separated out high-frequency sounds, which could not be heard well over background noise on regular TV sets, and restored them to their proper balance with other parts of the audio signal. Again, viewers at home benefited from more pleasant and natural sound when watching television programs.

High-definition television

Perhaps the most significant improvement in picture quality came with the development of high-definition television (HDTV). The first HDTV systems were introduced in Japan in the 1980s. These systems marked a major improvement in the visual quality available on a television screen. In order to be scanned by a TV camera and reproduced on a TV screen, an image is divided into horizontal lines. The American technical standard, which was established by the FCC in 1941, dictates that TV screens have 525 lines. The HDTV systems developed in Japan featured more than twice as many lines on a screen, allowing for a much sharper picture.

In 1987 the Japanese national broadcasting company, NHK, demonstrated a 1,125-line HDTV system in the United States. The remarkable picture quality impressed the FCC, which soon launched a competition to create an American HDTV system. A number of American electronics firms joined in the race to develop the new technology. The FCC expected all of the proposed HDTV systems to be compatible with the existing U.S. broadcasting system, which used an analog signal (continuous, measurable electronic impulses carried on radio waves). Under this system, every television channel was allowed a certain amount of space on the airwaves—6 megahertz (MHz) of frequency bandwidth—to broadcast its signal. A standard-definition TV picture fit into this space, or bandwidth, but the Japanese high-definition picture did not: it required 20 MHz of bandwidth. The FCC felt that the U.S. airwaves were too crowded to allow TV stations to expand their signals for high-definition broadcasting. Instead, the FCC wanted to find a way to squeeze more detailed pictures into the existing bandwidth.

The FCC received a number of proposals for adjusting HDTV to analog broadcasting. But then, in 1990, a California-based company called General Instrument (GI) announced that it had developed the world's first all-digital television broadcasting system. Unlike analog signals, which transmit information through continuous, measurable electronic impulses, digital signals turn data into a binary code consisting of long strings of the digits zero and one (for example, 1010100010111). This code can be understood by computers and all other types of digital devices. The main benefit of digital over analog transmission is that it allows a great deal more data to be sent over the same amount of bandwidth. For television signals, this means that digital technology can provide better picture and sound quality, as well as interactive features like program menus and on-demand movies and games.

The engineer who led the development of digital HDTV at General Instrument was Woo Paik, a Korean-born graduate of the Massachusetts Institute of Technology. His team found a way to compress 1,500 megabytes per second (mbps) of information into 6 MHz of bandwidth, which can usually carry only about 20 mbps of data. Their system compares each frame of a visual image and only transmits the parts that move or change. In other words, it provides just enough detail to make the human eye perceive a continuous picture with nothing missing. "Today's analog television system transmits a complete picture frame thirty times a second. But since most of the picture is unchanged from one frame to the next, a lot of redundant [repetitive] information is transmitted," Tube explained. "GI's digital system only transmits what changes in the picture, once it has presented a complete frame."

The FCC established technical standards for HDTV in 1994. It also rolled out a plan for the United States to make a gradual switch from analog to digital television broadcasting by 2006, although completion date for the transition was later moved back to 2009. Digital technology is expected to bring many changes to the television industry. It promises to allow networks to broadcast high-definition pictures over regular channels and allow stations to engage in multicasting, which means offering several different programs on a single channel. Digital television sets are also expected to be more interactive, giving viewers greater ability to select, respond to, and even change the content of programs.

For More Information


Barnouw, Erik. Tube of Plenty: The Evolution of American Television. New York: Oxford University Press, 1975.

Bilby, Kenneth. The General: David Sarnoff and the Rise of the Communications Industry. New York: Harper and Row, 1986.

Fisher, David E., and Marshall Jon Fisher. Tube: The Invention of Television. Washington, D.C.: Counterpoint, 1996.

Goldmark, Peter C. Maverick Inventor: My Turbulent Years at CBS. New York: Saturday Review Press, 1973.

Hilliard, Robert L., and Michael C. Keith. The Broadcast Century: A Biography of American Broadcasting. Boston: Focal Press, 1992.


"The FCC History Project: Historical Periods in Television Technology." Federal Communications Commission. (accessed on June 5, 2006)