Television

In addition to all these things, television brings its viewers a steady stream of programs that are designed to entertain. In fact, TV provides many more entertainment programs than any other kind. The programs include dramas; comedies; soap operas; sporting events; cartoon, quiz, and variety shows; and motion pictures.

About 98 percent of the homes in the United States have at least one television set. Altogether, there are about 200 million sets in the United States. On the average, a TV set is in use in each home for about seven hours each day. Because of its widespread popularity, television has an important influence on today's culture, including how people spend their time and money, and what they see and learn.

The name television comes from a Greek word meaning far and a Latin word meaning to see. Thus, television means to see far. Television systems change the light and sound waves from a scene into electronic signals. A television set receives these signals and turns them back into pictures and sounds.

Many scientists contributed to the development of television, and no one person can be called its inventor. Experiments leading to the invention of TV began in the 1800's, but progress was slow. Television as we know it today was not developed until the 1920's. It had little importance in communication until the late 1940's, when local over-the-air broadcasting of entertainment television began. Television stations used electronic signals called electromagnetic waves to send programs over the airwaves from a nearby transmitter to antennas in homes.

Today, over-the-air broadcasting is only one of several ways to transmit programs to TV viewers. About 60 percent of the American homes with television sets subscribe to cable television systems, which use cables to bring programs to the home. Other households subscribe to direct-broadcast satellite (DBS) systems, which enable viewers to receive signals directly from satellites. In addition, many homes have videocassette recorders (VCR's) that enable people to watch programs distributed through stores.

Television also has many uses other than broadcasting programs to the home. For example, schools, businesses, hospitals, and many other organizations use closed-circuit television. In closed-circuit TV, signals are sent--by way of wires--to only certain television sets rather than to all sets within the area that broadcast signals could reach.

Since the late 1970's, such equipment as videocassette recorders, videodisc players, and personal computers have changed the way people use television in their homes. For example, TV sets may be used to play electronic games and to watch prerecorded movies.

Commercial television. Commercial television stations broadcast many more entertainment programs than any other kind. These shows include light dramas called situation comedies; action-packed dramas about detectives, doctors, lawyers, and police officers; variety shows featuring comedians, dancers, and singers; and movies, including some made expressly for television. Entertainment programs also include quiz shows and soap operas (melodramatic plays), and cartoons and other children's shows.

Another kind of commercial television program is the documentary. A documentary is a dramatic, but nonfictional, presentation of information. Some TV documentaries entertain as well as inform. These include travel programs about people, animals, and things in faraway places. Television also presents documentaries about such serious social issues as alcoholism, drug abuse, poverty, and racial prejudice.

Commercial television stations broadcast many discussion, or talk, shows. On these shows, a host interviews people from many walks of life--including athletes, authors, motion-picture and TV stars, and politicians.

Commercial television stations cover almost every kind of sports event--from baseball and football to table tennis and skydiving. Every two years, TV brings its viewers the colorful Olympic Games--often from halfway around the world.

All commercial stations broadcast brief summaries of local, national, and international news every day. Also, stations often interrupt their regular program schedules to present extended coverage of special events, such as political conventions and presidential activities.

Advertising makes up an important part of commercial television. Television commercials appear between and during most programs. The vast majority of the commercials urge viewers to buy some kind of product--from dog food and hair spray, to cars and insurance policies. At election time, many political candidates buy advertising time on television to ask people to vote for them. A small percentage of TV advertising provides a public service. Public service ads include messages that tell people to drive carefully and follow other safety rules. They also include announcements about local community activities.

Commercial television attracts huge audiences. Often, more than 50 million people tune in to a top entertainment show or sporting event. On a typical day, more than 25 million homes have a television set tuned to one of the network evening news programs. Thus, it must be assumed that large numbers of people like what commercial television offers. Even so, many people criticize its coverage. They say that commercial TV shows too many programs designed only to entertain, and not enough programs that inform, educate, or provide cultural enrichment. The critics also claim that much of the entertainment is of poor quality because it aims at the largest possible audience. They criticize newscasts for being too brief to provide the real meaning of the news.

The people responsible for deciding what appears on commercial television respond to such criticisms by pointing out that commercial TV can stay in business only by selling much advertising time at high prices. To do this, the programs must attract large numbers of viewers. Statistics show that many more people watch popular shows and brief news reports than watch more sophisticated shows and in-depth news reports.

Public television programming focuses chiefly on educational and cultural subjects. Because public television stations are less dependent on advertising, it is not necessary for them to attract huge audiences.

Public stations broadcast educational programs on a wide range of subjects, from literature and physics to cooking and yoga. In some cases, viewers can earn college credits by passing tests based on what the programs teach. Some educational programs on public TV take much the same form as classroom instruction. But others use a more entertaining approach. Examples include "Sesame Street" and "Mister Rogers' Neighborhood," two lively, yet educational, children's shows.

Public television stations offer many programs that combine entertainment and cultural enrichment. They telecast such things as plays by leading dramatists, ballets and symphonies, and surveys of art and history. Such television shows draw up to 2 million viewers--a small audience by commercial TV standards, but a much larger one than ever attended a theater or concert hall.

About 90 percent of the public television stations in the United States carry an hour-long newscast on weekday evenings. In addition, public television often presents programs in which leading journalists and others who deal closely with current events participate in in-depth discussions of news developments.

Subscription television is television broadcasting paid for by the viewers. Most subscription TV is made up of cable systems. In addition, many people subscribe to satellite systems, particularly in areas where cable TV is not available.

Cable television has two important advantages over commercial and public television stations. First, it offers improved reception of network and local station programs. Second, it provides a greater variety of programming.

Commercial and public television stations send signals over the airwaves. Cable television delivers signals to home TV sets by way of cables. Cable television systems can send programs to places that either cannot receive TV signals through the air, or can receive them only with much interference.

Some cable systems carry more than 100 channels--far more than can be broadcast over the airwaves even in the largest urban areas. This increase in the number of channels available made narrowcasting possible. Unlike broadcasting, which tries to appeal to the largest possible audience, narrowcasting offers programs that appeal to a particular group. For example, cable channels may specialize in movies, news, sports, music, comedy, health, religion, weather, or Spanish-language programs. Such channels focus on attracting viewers with particular interests. Many communities also require cable operators to reserve channels for programs of local interest, such as city council meetings. Thus, cable television offers a wide variety of programming to its viewers.

Most cable networks sell advertising time and receive part of the monthly fee for basic cable service. Other cable channels do not sell advertising time. Pay channels, such as premium movie channels, rely on subscriptions that customers pay in addition to the monthly fee for basic service. Nonprofit channels offer public affairs programming without advertising.

Satellite television also offers improved reception and a greater variety of programs to its subscribers. Millions of homes now receive TV signals from direct-broadcast satellites (DBS). Subscribers use dish-shaped antennas to receive DBS signals.

Closed-circuit television has a number of specialized uses. Many schoolrooms have TV sets that receive special lessons by way of closed-circuit television. Also, a lesson in one class can be shown simultaneously to students in other parts of the school through closed-circuit TV.

Businesses use videotaped television programs extensively to train their employees. Many large corporations operate their own private TV studios. Some companies conduct nationwide meetings and conferences by live TV. This procedure, called teleconferencing, saves the time and expense of travel.

Closed-circuit TV in banks and prisons enables guards to observe many people at once. Hospitals use closed-circuit TV to monitor (keep track of) patients. Television cameras are placed in operating rooms to give medical students close-up views of actual surgical procedures.

Video entertainment systems include videocassette recorders (VCR's), videodisc and compact disc players, and electronic games.

Videocassette recorders enable people to tape television programs on blank videocassettes and play them back later. The VCR is attached to the user's television set. People also may buy or rent prerecorded videotapes. Many of these are tapes of movies, concerts, or sports events. With the use of a video camera, families can create their own videotaped television programs.

Videodiscs resemble phonograph records, but they carry both sound and pictures. These prerecorded programs are transmitted by a videodisc player to an attached TV set. Videodiscs are used in the home primarily for viewing movies and concerts of popular and classical music.

The information on a videodisc, as on other optical discs, is played back by a device called a laser inside the player. A videodisc holds up to 54,000 pictures, or frames, per side and can store a vast amount of information. The images on these frames may be observed singly, like the pages of a book. They also may be played in sequence to produce a moving picture. A videodisc player provides instant access to any frame on the disc.

In an interactive optical system, the videodisc player is linked to a computer. If a student answered a test question incorrectly, the disc might automatically respond with the appropriate information. Videodiscs have been used to teach chemistry to high school students and tank gunnery to soldiers.

Compact discs (CD's), another type of optical disc, also carry both sound and pictures. Because compact discs store information in digital (numerical) code, they can hold even more data than videodiscs can. With a special player and a remote control, a viewer can react to prerecorded programs by means of words and symbols shown on the TV screen. These interactive CD's have uses in education, entertainment, and other fields. See Compact Disc.

Electronic games often use a television screen as a game board. Such games, also called video games, are played on a computer-controlled unit connected to a TV set. Each video game has its own program on a cartridge that is inserted into the unit. Players operate controls that move electronic dots, lines, and other images that appear on the TV screen.

Most television productions take place in television studios. But television production companies also create shows in movie studios, on city streets, in stadiums, in deserts and jungles, and even underwater. Broadcasters telecast some programs live (as they happen). Live telecasts include coverage of political conventions, speeches by the President, and sports events. The parts of newscasts in which the announcers speak are also live. But most of the news stories shown on these programs come from videotape recordings.

Most TV programs--including almost all entertainment shows--are prerecorded, and then telecast later. The recording may be done on videotape or on film. Many prerecorded programs are produced from beginning to end, in the manner of a stage play. However, television production companies also use the piecemeal approach of the motion-picture industry. In the piecemeal approach, each scene is recorded separately, and spliced (connected together) later.

The first two parts of this section--Planning and preparation and Putting a show on the air--trace the production of a program in a television studio. But much of the information under these headings applies to all TV productions. The last part of this section describes other production methods.

The producer usually begins by obtaining a script and choosing a director. Sometimes--especially for uncomplicated shows--producers write their own script. They may also serve as their own director--in which case they become a producer-director. But more often, the producer assigns the script-writing job to a professional writer or team of writers, and the directing job to a professional director. The producer and director select the talent (actors, actresses, or other people who will appear on the show). The producer also chooses the production specialists needed to produce the show. These people may include an art director, a costume designer, and a composer. In addition, the producer works closely with the director throughout the production process. The producer of a news program decides which of the day's events to include in the newscast and in what order to present them.

Writers prepare the scripts for television programs. A television script is a written account of what is to be said and done during the program. The amount of detail a script contains varies, depending on the program. A talk show script, for example, may include only the host's opening remarks and some of the key questions to ask the guests. During most of the show, the host and the guests carry on adlibbed (unplanned) conversations. A script for a television drama, on the other hand, includes every word to be spoken by the actors and actresses. It also describes the actions they are to perform. For a newscast, writers prepare the script that the announcers read.

The director. As soon as the writers complete the script, the director reads it and tries to visualize ways to translate it into an actual television program. Directors get ideas about how the characters should speak, move, and generally behave. They decide what camera shots will be needed to create the effects they visualize. Sometimes, the director has an artist prepare a storyboard (a series of drawings) that shows how key parts of the program will look.

Production specialists. The producer and director call on many production specialists to help prepare for the program. An art director and artists and craftspeople who work with the art director design and build the show's scenery. A costume designer creates or obtains costumes needed for the production. A property manager gets special items called props for the show. These items include furniture, vases of flowers, and guns. Specialists in technical work also play a key role in the production process. They advise the producer and director on what kinds of cameras, microphones, and lights will be needed. A production manager, or production coordinator, sees to it that all the required equipment is available when needed.

Talent is a technical term for all the people who appear on television programs. A talent may be a performer, or an actor or actress. The talent who appear as themselves on television are performers. A talent who plays someone else is an actor or actress. Television performers include newscasters, sports announcers, and talk show hosts. The people who play roles in TV dramas and situation comedies are actors and actresses.

Selection of talent ranks among the key steps in the planning of a television program. The producer and director do this important job. If the talent are big stars, they may get television roles because of their fame and proven ability. But usually, the talent must audition (try out) for the parts they want to play. During an audition, the director and producer may ask the talent to take a screen test (perform in front of a camera).

The talent who earn a job get a script so they can study their lines. An actor or actress may have less than a week to learn the lines for a one-hour drama. Those who perform on TV's daily soap operas have only a few hours each day to memorize their lines.

Some television productions make use of cue cards to help the talent with their lines. A cue card is a large piece of cardboard or similar material with writing on it. The writing may be a key word or phrase, or an entire passage from a script. An off-camera stagehand holds the card up so the talent can see it.

Television performers who deliver commercials, news stories, and speeches often use an aid called a TelePrompTer. A TelePrompTer is a device that displays the words from a script. The display moves continuously, giving the talent a line-by-line view of the script. The TelePrompTer is located so that a person reading from it appears to be looking directly at the camera.

Composers and musicians. Most entertainment programs include music. A producer and director may decide they need an original musical composition for their show. If so, the producer hires a composer. The composer meets with the producer and director to discuss the theme, mood, and climaxes (dramatic high points) of the program. Composers base their compositions on what they learn about the show. Often, producers and directors use existing music for their programs. To do so, they must get permission from the holders of the copyright on the music, and pay them a fee.

The producer hires musicians and a conductor to perform the music. For prerecorded shows, the musicians often record the music after the actual program is produced. Then, technicians combine the music with the rest of the program.

Rehearsals are practice sessions for TV shows. Most TV productions require at least one rehearsal. Complicated productions often require many more.

During a rehearsal, the talent--under the director's guidance--practice their lines and their actions. The director also directs the actions of the camera operator and other off-camera workers.

Rehearsal for a dramatic production may begin with a script reading. Then, the director may call for a dry run (rehearsal without equipment or costumes). Many dry runs take place in a rehearsal room. This room has lines on the floor that indicate where such things as doors, chairs, and tables will be during the actual production. A director may watch a dry run through a director's viewfinder. This device resembles the viewfinder on a still camera. It enables the director to get an idea of how scenes will appear on television.

Finally, the director calls for a dress rehearsal, or camera rehearsal, in the studio. The goal of a dress rehearsal is to achieve a performance that is the same as the final production will be. In fact, directors sometimes record both the dress rehearsal and the actual production. In reviewing both recordings, directors may decide that parts of the dress rehearsal came out better than the actual production. They may then substitute the parts of the dress rehearsal they like for the corresponding parts of the actual production.

Television rehearsals stress the importance of split-second timing. A television show cannot run even a few seconds past its planned time, because that time is set aside for the next program.

Some studios have rows of seats, very much like a theater. Visitors can come to these audience areas and watch shows being produced.

Before the show begins, makeup artists apply makeup to the talent who will appear on the show. Makeup helps people look natural on camera. The talent put on special costumes, if the show calls for such costumes. Finally, they come into the studio and perform the production before the cameras.

The cameras used for shooting (making pictures of) the production are big instruments. They are mounted on devices that have wheels so the camera operators can move them around the studio to change the direction of their shots. Some cameras are operated by remote control from the control room instead of by an operator in the studio. Cameras can be tilted up and down to change the vertical angles and turned left and right to follow action. In addition, cameras can adjust from a close-up to a long-range view of a scene by means of a device called a zoom lens. The zoom lens enables the camera to vary televised scenes without moving. Zooming (moving in and out on scenes) is a widely used television production technique.

Microphones. Most studio TV productions involve the use of one or more boom microphones. A boom microphone is attached to a boom (long metal arm). A worker called the boom operator uses mechanical devices to move the microphone above and in front of the person speaking. For dramatic productions, it is essential that the microphone be kept out of camera view. Imagine a dramatic scene in which an actor lies exhausted in a hot desert, crying for help. If suddenly the boom microphone that hangs above him dropped into camera view, the scene would look ridiculous. Sometimes, television makes use of hidden microphones--either in addition to, or in place of, boom microphones. They may be hidden in or behind scenery or props.

Talk shows and other nondramatic productions may use boom microphones. But they also use microphones that viewers can see. These include desk microphones, which stand on desks or tables in front of performers; and hand microphones, which performers hold. Another kind of microphone, the lavalier, is hung around a performer's neck or attached to a performer's clothing. It may be in camera view or hidden in the clothing.

The control room. During a television program, scenes from each of the studio's cameras will appear on the viewer's screen. Pictures from other video sources, including filmed commercials, taped news stories, and slides that show titles, will also be seen. The job of determining which scene appears on the screen at a given time is performed in the control room. A program may also include sounds from several sources. Technicians in the audio control section of the control room regulate the sounds. In addition, engineers operate equipment that maintains the quality of the pictures and sounds.

The control room has several monitors (television sets). Each monitor shows the scenes from a different camera or other video source. The director watches the monitors when choosing which scenes to put on the air. The picture that is on the air at any given time appears on a monitor called the program, or line, monitor.

An important piece of equipment in the control room is the switcher. This instrument has many buttons, including buttons for selecting any of the studio cameras and any other picture source. On command from the director, a technician called the technical director (T.D.) presses buttons to change the televised scene. If the director wants the scene being photographed by camera number 1 to be shown, the director tells the T.D. to press the button for camera number 1. To change to camera number 2, the T.D. presses button number 2, and so on. This switching process goes on throughout the program. The switcher also enables television broadcasters to cut (switch instantly) from the program to commercials, and back again.

The switcher also has levers. By moving levers in various ways, the T.D. can combine scenes from two or more cameras or other video sources. The T.D. can also make other changes. These combinations and changes are called special effects. They include the dissolve, the super, the wipe, matting, and digital video effects.

The dissolve is a gradual change from one picture to another in which the two pictures overlap briefly. Directors use the dissolve to move smoothly from scene to scene and, sometimes, to indicate a passage of time.

The super, or superimposition, is the blending together of two scenes. Television often uses this device to show dream scenes. One camera shows a close-up of the face of the sleeping person, and the other shows the scene about which the person is dreaming.

A wipe is a special effect in which one picture seems to push another picture off the screen. A wipe stopped halfway is called a split screen. TV productions use the split-screen technique to show scenes from two different places at the same time. Other wipes include the circle and the diamond, in which the second picture appears on the screen as an expanding circle or diamond.

The matting technique may be used to change the background in a scene. A camera shoots a picture of a person against a bright blue background. Then a device called a matting unit replaces the blue with another picture so that it looks as if the person is standing in front of the new background. TV productions use this technique to place weather reporters in front of maps. Matting may also be used to show text over a scene.

Digital video effects (DVE) systems may be part of the switcher or separate devices. The T.D. can use them to perform a variety of special effects, including shrinking pictures and changing colors in a scene.

The sound inputs of a television program are controlled by an instrument called an audio console. An audio engineer operates this instrument. The audio engineer pushes buttons and moves levers to choose and mix together various audio inputs. For example, a scene of two people sitting in an automobile might require the audio engineer to mix the sounds of the people's conversation with recorded sounds of the automobile engine, outside traffic, and mood music. The audio engineer also controls the volume of sounds.

Taping the program. Broadcasters usually record live programs on videotape at the same time as they telecast them. This allows them to rerun all or parts of a show at a later time. For example, videotaped highlights of a live telecast of a speech by the President are often shown later on newscasts. Videotapes of live sports events allow sportscasters to rerun and analyze key plays immediately after they happen. This process is called instant replay.

Master control is the electronic nerve center of a television station. Much of the electronic equipment that helps create television pictures is located there. A program goes from master control by cable or microwave to the transmitter. Then, the transmitter sends it on its way to the viewers. Master control also has equipment for switching from program to program. The programs include those that originate at the station, at network headquarters, and at remote locations.

The piecemeal approach involves recording a program on videotape or film scene-by-scene with stopdowns (stops) between scenes. Each recorded scene is called a take. After each take, directors can play back the tape or film and judge its merits. If they like the take, they go on to another one. If they do not like it, they can call for a retake (shoot the scene over again). The piecemeal approach also allows directors to shoot scenes out of order. If, for example, the first and last scenes of a TV play happen in the same location, the director may shoot them one right after the other. Upon completion, film or tape editors splice all the scenes together in their proper order to create a continuous story.

Filming and taping programs. Many TV producers use film or video cameras to create programs that take place at several locations. For example, television news programs, which report on widely scattered events, use film or videotape. In addition, motion-picture studios create many entertainment programs with film cameras.

After camera operators film a program, broadcasters telecast it from a telecine unit, a device that converts film images to TV signals. For technical information, see Telecine later in this article.

Prerecorded telecasts include nearly all entertainment programs. These programs are produced straight through in the television studio and recorded on videotape for broadcast later. The videotape machine stands in or near a special part of the television studio called master control. The director reviews the finished tape, and tape editors correct any major errors in it. Then, the tape is stored until the time the program is scheduled for broadcasting. For technical information on videotape, see Videotape recording later in this article.

Remote telecasts. Almost all remote telecasts are broadcast live. They include telecasts of sports events and political conventions. Producers of these programs use regular-sized television cameras. But they also use cameras small enough to be carried around. These handheld cameras help TV crews cover the huge area of a sports field or convention hall. Broadcasters park a remote truck near the place of the telecast. This truck contains control room and master control equipment needed to create TV signals. The signals travel by microwave or wire from the truck to the transmitter.

The number of TV stations accounts for only part of television's impact on the American economy. The manufacture and sales of television sets and broadcasting equipment became big businesses because of the rise of television. In addition, broadcasting, manufacturing, and sales created thousands of new jobs.

The national networks. About three-fourths of all commercial television stations in the United States are affiliates of one of the four major national networks. That is, they agree to carry programs provided by these networks. The major national television networks are those of Capital Cities/ABC Inc., CBS Inc., the National Broadcasting Company (NBC), and the Fox Broadcasting Company. The networks create some of their programs and buy others from independent producers.

An affiliate agrees to carry programs provided by a network. The network pays the affiliate for carrying the programs. Sponsors, in turn, pay the networks for showing their commercials on the stations.

A network's success depends on its ability to select programs that attract large audiences. The bigger a program's audience, the more money sponsors will pay for the right to show commercials on it.

The TV executives who choose network programs know that famous entertainers and championship sports contests usually attract large audiences. But these executives cannot be certain how many viewers other shows are likely to attract. They are helped in choosing programs by specialists in audience research. Such specialists collect data about people's interests and the kinds of programs they like to watch. These specialists also gather the responses of audiences that are invited to view special "pilot" episodes of new programs. Such research has limited success in predicting a program's popularity. As a result, network executives must ultimately rely on their own intuition in choosing programs.

The success of a program is measured in ratings and shares. Ratings measure the percentage of all households equipped with television that are tuned to a particular program. Share measures the percentage of TV homes with a set switched on that are tuned to a particular program. The A. C. Nielsen Company ranks as the most important national audience measurement service. It provides television stations and advertisers with information about ratings and share and with demographic data about audiences. Demographic data describe the makeup of an audience in terms of sex, age, income, education, race, place of residence, and other features. The Arbitron Ratings Company is the leading American audience measurement service at the local level.

A national audience survey typically consists of about 3,000 households that are paid a small fee. The viewing habits in these households supposedly reflect the habits of the entire nation. Networks usually cancel a program that receives low ratings, often after only a few shows.

Commercial stations. More than 1,100 local commercial stations operate in the United States. About three-fourths of them are affiliates of the four major networks. The rest operate independently or as affiliates of smaller networks.

An affiliate carries many hours of network programs daily. But in 1971, the Federal Communications Commission (FCC)--which regulates broadcasting in the United States--limited the amount of network programming affiliates can carry during prime time. Prime time refers to the evening hours, when television programs draw the largest audience. The FCC ruled that local stations in the nation's 50 largest television markets cannot broadcast more than 3 hours of network programs during prime time. This ruling was designed to force the stations to offer a wider variety of programs--especially programs of local interest--during the prime-time period.

In spite of this FCC ruling, most nonnetwork programs are old movies, talk shows, game shows, and reruns of old network shows. These programs are syndicated--that is, sold to the stations by independent organizations called syndicates. Affiliates or independent stations prefer to buy syndicated programs rather than produce new programs because it is far less expensive. In addition, syndicated programs are generally well known. Local stations fill some time with shows they produce themselves, especially newscasts. Both affiliates and independent stations sell time to advertisers to cover the costs of their programs.

Public stations. More than 300 public TV stations operate in the United States. These stations create many of the programs they show and buy programs from independent producers. Often, a program created by one public station is carried by many others. An agency called Public Broadcasting Service (PBS) serves as a distributor of locally produced public programs.

Public stations are nonprofit organizations, but they need money to cover their production and operating costs. The largest part of a station's funds come from viewer contributions. Businesses and foundations also help support public television. Local and state taxes help support many public stations. Stations also get funds from the Corporation for Public Broadcasting (CPB).

The CPB, created by Congress in 1967, gets most of its funds from the federal government. The CPB helps public stations serve their communities through grants for programming and technical facilities. It also finances the production of programs distributed by PBS and sets policies for a national public broadcasting service.

Cable television systems bring television to the home by means of cables rather than through the air. Cable TV, which began in the early 1950's, is one of the fastest-growing parts of the television industry. Its original purpose was to bring network and local station programs to places that either cannot receive TV signals through the air, or can receive them only with much interference. Such places include isolated communities, mountain valleys, extremely hilly regions, and areas with heavy concentrations of tall buildings.

Improved reception of regular television programs still ranks as an important purpose of cable television. But since the 1960's, people have begun to use it for other purposes. A single cable system can carry more than 100 channels. Thus, a cable system can transmit regular network television programs and also provide a wide variety of special features. Some cable systems offer adult education classes; continuous news, weather, and stock market reports; programming from distant independent TV stations; first-run motion pictures; and special sporting events. In many communities, channels are set aside for coverage of such local activities as city council and school board meetings.

In 1993, there were about 11,000 cable television systems in the United States. The largest of these systems provided TV to about 900,000 homes. Others served fewer than 100 homes. Altogether, cable TV served more than 55 million homes in over 30,000 communities.

Cable TV has great economic potential despite the high cost of installing cable systems. Many operators charge an installation fee. Subscribers pay a monthly fee for the basic service plus additional fees for special services. Operators can also create their own programming and sell advertising time to sponsors.

Television awards are presented each year by a number of organizations. The best-known awards, the Emmys, are given by the Academy of Television Arts and Sciences and by the National Academy of Television Arts and Sciences. The two academies recognize achievements of the preceding year in various fields of the TV industry. Some local chapters of the National Academy also present Emmys for local programming.

In Canada. About 98 percent of all homes in Canada have television sets. About 3 out of every 4 households subscribe to cable television services.

The Canadian Broadcasting Corporation, (CBC), a publicly owned corporation, operates two national television networks. One network broadcasts in English, and the other broadcasts in French. About 30 television stations in the Canadian provinces are affiliated with the CBC. The CBC delivers programs by satellite to people in northern Canada. Some of these programs are in Indian and Inuit languages.

Canada's other national network is the CTV Television Network, with 23 affiliates. Smaller networks operate in several provinces. Canada has about 70 privately owned television stations and about 2,000 licensed cable systems. Many of the privately owned stations depend on programs produced in other countries, especially the United States. Canadian homes receive nearly all of the network programs broadcast in the United States.

Careers in television. The television industry has thousands of job opportunities. It needs such workers as writers, producers, directors, camera operators, engineers, electronic technicians, stagehands, lighting specialists, graphic artists, and set designers to help produce TV shows. Actors, actresses, and performers are needed to appear in them. TV news departments provide various jobs for journalists. TV broadcasting also creates many jobs for specialists in management, market research, and advertising.

The television industry also employs workers in technical fields outside of broadcasting. Scientists and engineers are needed to design television equipment. Factory workers manufacture television sets and other TV equipment. Technicians service home receivers.

Almost all careers in television require special training. Many colleges and universities have departments that train students in nontechnical broadcasting careers. Journalism schools teach courses in broadcast--and printed-media--journalism. Technological institutes and engineering departments of colleges offer training in technical areas of television. Information on television careers is available from the National Association of Broadcasters in Washington, D.C.

Effects on leisure time. A typical adult spends more time watching TV than doing anything else except sleeping and working. Watching television ranks as the most time-consuming leisure activity among adults. It takes time away from other activities, such as reading, conversation, social gatherings, and exercise.

Effects on learning. Television contributes greatly to what home viewers learn. It benefits people by widening their experience. On the other hand, TV also may contribute to harmful impressions of the world.

Enriched experience. No communication system has ever provided so many people with as wide a range of new experiences as television has. Without leaving their homes, TV viewers can watch government officials perform important functions, and see how people in far-off lands look and live. Television takes viewers to deserts, jungles, and the ocean floor. A TV viewer can see how a famous actor performs the role of Hamlet, and how top comedians draw laughter. Television gives its viewers a glimpse of real-life tragedy, as when it covers the victims of war, natural disasters, and poverty. It also captures moments of great triumph, such as when astronauts first set foot on the moon. However, some authorities question how much specific information viewers remember from watching television.

Harmful impressions. Many social scientists believe that people are likely to form two negative impressions from watching a lot of television. One of these impressions is that many people are better off than they are. The other is that the world is an unfriendly place, filled with untrustworthy people and risky circumstances.

Television programs often show people who lead more glamorous lives and have more material possessions than most viewers. In addition, TV commercials constantly urge viewers to buy various goods. Many sociologists believe that as a result, the material expectations of TV viewers are raised, sometimes to an unrealistic level. One harmful effect results when people fail to achieve the success they see on TV and become dissatisfied or bitter.

The violent, crime-filled world shown on TV may contribute to an impression of an evil world. Studies indicate that people who watch a great deal of television are more likely to hold fearful or negative views of the world than those who watch less TV. However, some researchers argue that people who watch a lot of television already hold such views.

Effects on society. Television has brought about major changes in several parts of American society, including politics, motion pictures and radio, and sports.

Politics. Every election year, thousands of political candidates use television in their campaigns. They buy commercial time to urge voters to support them. They also appear in debates with other candidates and answer interviewers' questions about their views. Television plays its greatest role in presidential races. Before TV, presidential candidates tried to make personal appearances and speeches in as many cities and states as possible. Today, many candidates reach more voters through a single television appearance than through all the in-person campaigning they do.

The most widely used form of political advertising in television is the spot announcement. Spot announcements are political messages that last 10 to 90 seconds. News programs often televise only a sentence or two, called a sound bite, from a candidate's remarks. These contrast sharply with the long political speeches that are typical of traditional in-person campaigning.

Television does much to promote interest in politics and political issues. But political advertising on TV also draws criticism. Critics say spot announcements are too short to allow candidates to discuss issues. Instead, candidates use the time to present oversimplified statements. Critics also claim that, because television time is so expensive, TV campaigning gives unfair advantage to the candidates with the most money.

Motion pictures and radio. From the 1920's through the 1940's, films and radio were the chief forms of entertainment for millions of Americans. Many people went to the movies at least once a week. They listened to comedies, dramas, and other entertainment programs on the radio almost every night. The rise of TV in the 1950's caused a sharp drop in movie attendance. Ever since, the movie industry has faced economic problems. Radio entertainment changed completely after TV became a part of American life. Almost every radio entertainment show went off the air. Recorded music became the chief kind of radio programming.

Professional sports have long attracted millions of spectators yearly. But many more millions now watch the events on television. Television networks and stations pay team owners huge amounts of money for the right to televise games. These funds, in turn, help owners pay the huge salaries of today's professional athletes. Television also helps increase the popularity of sports. For example, the popularity of professional football has soared largely because of television. On the other hand, minor league baseball lost much of its audience after television brought major league games into the home.

Effects on young people. There is little agreement about how television affects young people. Parents have long been concerned about the amount of time young people spend watching TV. Studies have linked watching a lot of television with poor performance in school. However, these studies do not prove that TV viewing actually causes students to perform poorly. Watching television may simply be an activity preferred by young people who do poorly in school. Other studies suggest that televised violence encourages aggressive behavior.

A TV set uses these signals in re-creating the picture on its screen. The scanning process puts the picture back together piece by piece. A person watching TV does not realize this is happening. The process works so quickly that the viewer sees only a complete picture.

Sending television pictures and sounds involves three basic steps. (1) The light and sound waves from the scene being televised must be changed into electronic signals. (2) These signals must be transmitted to the television receiver. (3) The receiver must unscramble the signals and change them back into copies of the light and sound waves that came from the original scene.

This section describes how a TV camera creates video signals. It also explains how video signals are produced by telecine and videotape. TV audio signals are created in the same way as radio signals. For information on this process, see Radio.

TV stations broadcast composite color signals. These video signals produce a color picture when received on a color television set, and they produce a black-and-white picture on a black-and-white set.

Color TV uses the three primary colors in light--red, blue, and green--to produce full-color pictures. The proper mixture of these three colors can produce any color of light. For example, a mixture of red and green light produces yellow light. Equal amounts of red, blue, and green light produce white light.

The television camera. In producing a composite color signal, the TV camera must (1) capture the image of the scene being telecast; (2) create video signals from the image; and (3) encode the color signals for transmission. To perform these tasks, a television camera uses a lens, a system of mirrors and filters, image sensors, and complex electronic circuits.

Capturing the image. The lens gathers the image (picture) of the scene in front of the camera. Like the lenses in other cameras and the human eye, the TV lens focuses (collects and bends) the light from the scene in order to form a sharp image. This image contains all the colors of the scene. However, in order to produce color signals, the camera must split the full-color image into three separate images--one for each primary color.

Most TV cameras use two dichroic mirrors to split the image into the primary colors. These mirrors, like the color filters used in photography, reflect light of only one color and let other colors through. The first mirror reflects the blue image and allows red and green light to pass through it. The second mirror reflects the red image, leaving only the green image. Other mirrors reflect each image to a separate image sensor. In many cameras, this color separation is done by color filters and prisms contained in a small compartment called the prism block.

Creating the video signals. An image sensor changes the light image into video signals. A black-and-white camera has only one sensor. Most high-quality color cameras have three sensors. These sensors create a separate video signal for each of the three primary colors. Many small, lower-quality, portable cameras are equipped with a single sensor. This sensor has many thin red, blue, and green filter stripes on its surface. The stripes divide the light into the three primary colors, and the sensor then converts each of the colors into a separate video signal.

Two types of image sensors may be used in television cameras. Tube cameras contain improved versions of a vacuum tube called a vidicon. Solid-state cameras contain electronic sensing mechanisms called charge-coupled devices, or CCD's. Solid-state cameras are smaller, lighter, and more reliable than tube cameras. This section describes the working of one sensor in cameras that have three.

A vidicon tube has a glass faceplate at its front end. In back of the faceplate is a transparent coating called the signal plate. A second plate, called the target, lies behind the signal plate. The target consists of a layer of photoconductive material that conducts electricity when exposed to light. At the rear of the tube is a device called an electron gun.

Light from the image reaches the target after passing through the faceplate and the signal plate. The light causes negatively charged particles called electrons in the photoconductive material to move toward the signal plate. This movement leaves the back of the target with a positive electric charge. The strength of the positive charge on any area of the target corresponds to the brightness of the light shining on that area. The camera tube thus changes the light image gathered by the lens into an identical electric image of positive charges on the back of the target.

The electron gun shoots a beam of electrons across the back of the target. The beam moves across the target in an orderly pattern called a scanning pattern. As the beam moves across the target, it strikes areas with different amounts of positive charge. Areas of the target that have the strongest charge attract the most electrons from the beam. This occurs because particles of unlike electric charge attract each other. Other areas of the target attract fewer electrons. The electrons from the beam move through the target and cause an electric current to flow in the signal plate. The voltage of this current changes from moment to moment, depending on whether the beam is striking a bright or dim part of the image. This changing voltage is the video signal from that camera tube.

A charge-coupled device is a silicon chip with tiny, square photoconductive elements (parts) arranged on its surface. Light falling on an element (also called a pixel) causes electrons to flow into the element's capacitor, a device that stores an electrical charge. As more light falls on the element, more electrical charge accumulates in the capacitor. The CCD thus changes the light coming through the camera lens into an identical electric image. The CCD then reads out the image by releasing the charge stored in each capacitor to cause an electric current to flow. This current is the video signal from that CCD. The CCD releases the capacitor charges according to the scanning pattern.

Most television systems use interlaced scanning. This pattern starts at the top of the picture and scans the odd-numbered lines from left to right. After it reaches the bottom, it returns to the top and scans the even-numbered lines.

The scanning pattern of TV cameras in the United States is made up of 525 lines (262 1/2 odd-numbered and 262 1/2 even-numbered lines). The camera completes one field each time it scans 262 1/2 lines. Two fields make up a complete television picture, called a frame. The camera scans so quickly that it produces 30 complete frames in a second. This speed is fast enough so the television picture shows moving images smoothly.

Each of the three image sensors converts its particular primary color to a video signal by means of the scanning process. Wires carry the signals to electronic circuits in the camera that amplify (strengthen) them. The three signals then go to the encoder.

Encoding the color signals. At the encoder, the three video signals are combined with other signals to produce a composite color signal. The first step in this process involves combining the three video signals into two color-coded signals and a black-and-white signal. The two color-coded signals are called chrominance signals, and the black-and-white signal is called a luminance signal. A circuit in the encoder, called the matrix, performs this function.

The encoder then combines the chrominance and luminance signals and adds a color burst and a synchronization signal. The color burst enables a color TV set to separate the color information in the chrominance signals. This information, along with the luminance signal, produces a full-color picture on the TV screen. A black-and-white set uses only the luminance signal. The synchronization signal locks the receiving set into the same scanning pattern as that used by the camera.

Telecine (pronounced TEHL uh sihn ee) is equipment that transfers motion pictures or slides into TV signals. The name comes from the word television and the word cinema, which refers to film. Telecine uses a combination of film and slide projectors and a single television camera to create such signals. A typical telecine unit, often called a film chain, consists of two motion-picture projectors, a slide projector, a multiplexer, and a telecine camera. The multiplexer is a system of mirrors that directs the images from film or slides into the telecine camera. The camera then converts these images into video signals.

Videotape recording stores television pictures and sound as magnetic impulses on tape. The video signals are usually recorded as diagonal (slanted) tracks in the center of the tape, and sound and control signals are recorded along the tape's edge. Unlike film, which must be developed before showing, a videotape can be played back immediately.

Character generators and video paint boxes work like small computers to generate letters or pictures. TV productions use these graphics to create a variety of materials, including advertisements and weather maps.

Color television transmission begins with a television camera. A mirror system breaks light from a scene into the three primary colors of light--red, blue, and green. At the same time, a microphone changes sounds into audio signals. Camera tubes then convert the color light images into electronic video signals. These signals go to the encoder, which produces a compatible color signal for transmission. The transmitter combines the audio and video signals for broadcast from the antenna. From The World Book™ Multimedia Encyclopedia ©1998 World Book, Inc., 525 W. Monroe, Chicago, IL 60661. All rights reserved. World Book diagram by Mas Nakagawa.

A camera tube produces a video signal for one of the primary colors. Light striking the tube causes a pattern of electric charges to form on its target. As an electron beam scans (moves across) the target, electrons flow from the target and become one of the primary color signals. From The World Book™ Multimedia Encyclopedia ©1998 World Book, Inc., 525 W. Monroe, Chicago, IL 60661. All rights reserved. World Book diagram by Mas Nakagawa.

Broadcasting. Before a TV signal is broadcast, the transmitter boosts its frequency (rate of vibration). A TV signal needs a high frequency to carry the picture information through the air. The transmitter amplifies the signal so it has enough power to reach a large area.

The transmitter increases the frequency of both the video and audio signals by a process called modulation. High-frequency electromagnetic waves, called carrier waves, are first generated by the transmitter. The transmitter uses the video signal to vary the amplitude (strength) of the carrier waves to produce the video part of the TV signal. This process is called amplitude modulation (AM). The video signal is then amplified to a power of 1,000 to 100,000 watts.

The transmitter uses the audio signals to modulate another carrier wave, which becomes the audio part of the TV signal. This process, called frequency modulation (FM), shifts the frequency of this carrier wave slightly. The transmitter then combines the modulated video and audio carrier waves to form the TV signal.

A wire called the transmission line carries the television signal to the transmitting antenna, which releases the signal into the air. Television stations erect their antennas on high buildings or towers so the signal can reach as far as possible. The maximum range of most television signals is from 75 to 150 miles (121 to 241 kilometers).

Television stations in the same area transmit on different frequencies so their signals do not interfere with one another. The group of frequencies over which one station broadcasts is known as a channel.

Sixty-eight channels are available for broadcasting in the United States and Canada. These channels are divided into two groups. Channels numbered 2 through 13 are called very high frequency (VHF) channels. VHF refers to signals with a frequency between either 54 megahertz (54,000,000 vibrations per second) and 72 megahertz, 76 and 88 megahertz, or 174 and 216 megahertz. Channels numbered 14 through 69 are called ultrahigh frequency (UHF) channels. UHF signals have a frequency between 470 and 806 megahertz.

Coaxial cable and fiber-optic cable are used to carry television signals for long distances or to areas that have difficulty receiving signals. The networks often send programs to their affiliated stations through coaxial cables. The affiliates then broadcast the programs to their viewers. Cable television systems use coaxial or fiber-optic cables to carry signals to the homes of subscribers. See Fiber Optics.

Microwaves are electromagnetic waves, similar to television signals. Tall relay towers spaced about 30 miles (48 kilometers) apart across the country carry programs from the networks to affiliate stations on these waves. Equipment in a tower automatically receives, amplifies, and then retransmits the microwave signal to the next tower. The affiliate stations change the microwave signals back into TV signals.

Satellites carry television signals between stations where cables or microwave towers cannot be built. For example, satellites relay signals across oceans. Satellites work like relay towers in space. They receive coded TV signals from a special earth station, amplify them, and send them on to another earth station. The two stations may be thousands of miles or kilometers apart.

Satellite television systems use direct-broadcast satellites to carry signals directly to the homes of subscribers. Such signals are received by dish-shaped antennas. Many older antennas measure about 10 feet (3 meters) across. Some newer home antennas measure only 18 inches (46 centimeters) across.

A color television receiver picks up television signals with its receiving antenna. The signals travel to the tuner, which selects the desired station. Electronic circuits within the TV set separate the television signal into audio and video signals. The set amplifies the audio signal and changes it into sound. A decoder changes the video signals into primary color signals. Three electron guns in the picture tube--one for each primary color--scan the screen. The screen is covered with tiny phosphor dots of red, blue, and green. When struck by a beam, the colored dots glow and form the color picture. From The World Book™ Multimedia Encyclopedia ©1998 World Book, Inc., 525 W. Monroe, Chicago, IL 60661. All rights reserved. World Book diagram by Mas Nakagawa.

The picture tube screen, a part of which is shown here, has more than 300,000 colored phosphor dots arranged in groups of three on its surface. A metal shadow mask behind the screen has holes that keep each electron beam in line with its own color dots and away from dots of other colors. From The World Book™ Multimedia Encyclopedia ©1998 World Book, Inc., 525 W. Monroe, Chicago, IL 60661. All rights reserved. World Book diagram by Mas Nakagawa.

Receiving antenna. A good antenna collects a strong enough television signal for the receiver to produce a picture. A simple indoor antenna, commonly called rabbit ears, picks up a strong enough signal within a few miles or kilometers of the transmitter. At greater distances, a more elaborate antenna mounted on the roof may be needed. The best reception results when the antenna is pointed toward the desired station. Some antennas can be rotated by remote control to align them with widely separated stations.

Tuner. Signals from the antenna are fed into the set's tuner. The tuner selects only the signal from the station the viewer wants to receive. It shuts out all others. Most TV sets have two tuning devices. One device selects the VHF channels, 2 through 13, and the other device selects the UHF channels, 14 through 69.

Amplifiers and separators. From the tuner, the television signal goes to a group of complicated electronic circuits in the set. These circuits amplify the signal and separate the audio and video portions of it. The audio signals are changed into sound waves by the speaker. The video signals go to the picture tube, or kinescope, where they re-create the picture.

A color set has circuits that use the color burst to separate the video signal into the two chrominance signals and the luminance signal. Another group of circuits, called the decoder or matrix, transforms these signals into red, blue, and green signals that duplicate the signals from the three camera tubes.

The picture tube transforms the video signals into patterns of light that duplicate the scene in front of the camera. One end of the picture tube is rectangular and nearly flat. This end forms the screen of the television set. Inside the set, the picture tube tapers to a narrow neck. The neck of a color picture tube holds three electron guns--one each for the red, blue, and green signals. A black-and-white tube has only one electron gun.

Each electron gun in a color picture tube shoots a separate beam of electrons at the screen. Each beam scans the screen just as the beam in each camera tube scanned its target. The synchronization signal, which is a part of the video signal, ensures that the picture tube's scanning pattern follows exactly the pattern used by the camera. The beams must be in step with each other in order to produce a picture.

The screen of a color tube is coated with dots or stripes of red, green, and blue phosphors. These dots or stripes glow with their respective color when struck by an electron beam. A metal plate perforated with thousands of tiny holes lies about 1/2 inch (13 millimeters) behind the screen. This plate is called the shadow mask. Its holes keep the beams from hitting any color phosphors but their own.

The amount of light given off by the phosphors depends on the beam's strength at the instant it strikes them. Since the beam's strength is controlled by the video signal from the camera, the phosphors are bright where the scene is bright and dark where the scene is dark. When the TV set shows a color program, the three colored phosphors blend together in the viewer's mind to produce all the colors in the original scene (see Eye). The phosphors appear to produce only differing amounts of white light when showing a black-and-white program.

Digital television represents one of the biggest changes in television since the introduction of color in the 1950's. Digital systems convert television signals into sequences of 1's and 0's--that is, the same numerical code used by computers. Digital systems provide stronger and more reliable signals. Such signals are less likely to be disrupted by electrical interference from appliances and thunderstorms or by reflections from tall buildings and aircraft.

Digital systems also improve TV pictures by making it possible for television signals to carry more information. Digital systems use a technique called data compression that removes unnecessary information from the signal. For example, a frame of a movie or a television signal usually resembles the one before it. Digital systems take advantage of digital memory in the receiver to avoid retransmitting the parts of the picture that remain the same. The system can then fit higher-quality signals into existing channels.

High-definition television (HDTV) produces super-sharp images. HDTV employs over 1,000 scanning lines, each of which carries a greater amount of detail than do today's lines. Other improvements offered by HDTV include wider screens, digital transmission of video and sound, and progressive scanning. This scanning pattern offers greater clarity than interlaced scanning because it scans all the lines every time. Limited HDTV transmissions began in Japan in 1989. The television industry hopes to bring HDTV to U.S. and Canadian viewers in the late 1990's and to broadcast all U.S. programming in HDTV by 2006. HDTV was scheduled to begin in Europe in the late 1990's or early 2000's.

Flat-panel TV sets. In the late 1990's, flat, lightweight television sets became available that could be hung on the wall like a picture. Manufacturers are using a number of different technologies to develop these flat-panel televisions.

The FCC also sets standards for broadcasters. The agency cannot censor programs, but it has the power to take away, or refuse to renew, a station's license if the station violates the standards too much. The FCC expects stations to avoid obscenity and pornography in their programs. The agency requires stations to provide public services and programs designed to meet the needs of their local communities. Another FCC standard requires television broadcasters to give equal time to all legally qualified candidates for public office. In addition, the FCC, along with the Federal Trade Commission (FTC), evaluates truthfulness in television advertising.

Congress can also regulate broadcasting. For example, it passed a law prohibiting cigarette advertising on television. The law was based on the government's conclusion that cigarette smoking is harmful to health. In 1996, Congress passed the Telecommunications Act, which required that, by 1998, all new television sets contain a computer chip that would enable parents to block programs they considered inappropriate for their children. To this end, the television industry would rate programs on their explicitly violent or sexual content. The chip, which was popularly known as the "V" chip (for "violence"), could block out programs as instructed according to the rating.

Broadcasters and regulations. Broadcasters generally oppose government regulations. They say programming regulations interfere with their rights to freedom of expression. Most members of Congress disagree, as do many citizens' groups. They claim that because the airwaves are public property, the government must create regulations that serve the public's interest.

The first radio operators sent code signals through the air. By the early 1900's, operators could transmit words. Meanwhile, many scientists had conducted experiments involving the transmission of pictures. As early as 1884, Paul Gottlieb Nipkow of Germany had invented a scanning device that sent pictures short distances. His system worked mechanically, rather than electronically as television does. In 1922, Philo T. Farnsworth of the United States developed an electronic scanning system. In 1925, John Logie Baird, a Scottish engineer, gave the first public demonstration of a mechanical television system. Vladimir K. Zworykin, a Russian-born American scientist, invented the iconoscope and the kinescope in 1923. The iconoscope was the first television camera tube suitable for broadcasting. The kinescope is the picture tube used in TV receivers. Zworykin demonstrated the first completely electronic, practical television system in 1929.

The start of broadcasting. Many experimental telecasts took place in the late 1920's and the 1930's. The British Broadcasting Corporation (BBC) in Britain, and CBS and NBC in the United States were leaders in experimental telecasts. World War II and the economic problems that followed the war caused the BBC to abandon TV experiments. The United States moved far ahead of the rest of the world in TV broadcasting.

In 1936, the Radio Corporation of America (later RCA Corporation), which owned NBC, installed television receivers in 150 homes in the New York City area. NBC's New York station began experimental telecasts to these homes. A cartoon of Felix the Cat was its first program. NBC established the first regular TV broadcasts in the United States in 1939. The United States entered World War II in 1941. Television broadcasting was suspended until after the war ended in 1945.

The television boom. The national networks--all based in New York City--resumed broadcasting shortly after the war. At first, their telecasts reached only the Eastern Seaboard between Boston and Washington, D.C. But by 1951, they extended coast-to-coast. TV stations sprang up throughout the country. Entertainment, news, special events, and sports contests replaced the simple, largely experimental, prewar shows.

The American people became fascinated with the idea of having so wide a range of visual events available in their homes. The demand for TV sets became enormous. In 1945, there were probably fewer than 10,000 sets in the country. This figure soared to about 6 million in 1950, and to almost 60 million by 1960. In TV's early days, people who had no set often visited friends who had one just to watch television. Also, many stores placed television sets in windows, and crowds gathered on the sidewalk to watch programs.

Early programs. Milton Berle became the first television entertainer to attract a huge, nationwide audience. His show, "The Texaco Star Theater," was filled with zany comedy routines. It ran from 1948 to 1956, and often attracted 80 percent of the TV audience. "I Love Lucy," starring Lucille Ball, went on the air in 1951. This early situation comedy also attracted a huge following. Westerns such as "Gunsmoke" and "Have Gun Will Travel" became popular in the mid-1950's. Other popular early entertainment programs included Ed Sullivan's variety show, "The Toast of the Town"; the comedy-variety program "Your Show of Shows," starring Sid Caesar; professional wrestling matches; and quiz shows offering prizes of thousands of dollars. A major scandal hit TV in 1959, when it was learned that quiz show producers had helped some contestants answer questions.

Coverage of special events did much to widen TV's appeal. In 1951, TV broadcast the Kefauver hearings, in which U.S. Senator Estes Kefauver and his Senate committee questioned alleged mobsters about organized crime. In 1954, TV covered the Army-McCarthy hearings. Viewers watched spellbound as Senator Joseph R. McCarthy accused the U.S. Army of "coddling Communists," and the Army charged McCarthy's staff with "improper conduct." The hearings reached a dramatic climax when Joseph Welch, a soft-spoken lawyer for the Army, and the outspoken McCarthy clashed in an emotion-filled argument.

The 1960's opened with a milestone of television broadcasting. During the fall of 1960, presidential candidates John F. Kennedy and Richard M. Nixon faced each other and the nation in a series of TV debates. It marked the first time presidential candidates debated on TV. Many people believe the debates made an important contribution to Kennedy's victory in the 1960 election.

Popular entertainment remained the major part of television's coverage during the 1960's. But TV also reflected the turmoil that marked American life. President Kennedy was assassinated on Nov. 22, 1963. Two days later, millions of viewers witnessed one of the most startling scenes ever shown on television. In full view of TV cameras, Jack Ruby shot and killed accused Kennedy assassin Lee Harvey Oswald as policemen were taking Oswald from one jail to another.

From the mid-1960's on, television regularly brought viewers battle scenes from the Vietnam War. The conflict was sometimes called "the first war to be fought on television." Television viewers also watched war protesters demonstrate--sometimes violently--and witnessed bitter debates over the war policy of the United States. Civil rights protests by blacks and other minority groups also became part of TV coverage.

Technological advances made during the 1950's and 1960's helped improve the physical quality of telecasts. In TV's early days, most screens measured 7 or 10 inches (18 or 25 centimeters) diagonally. Today, 21- and 25-inch (53- and 64-centimeter) screens are common. In the 1970's, manufacturers introduced projection television systems, which beam programs onto a screen as large as 7 feet (2 meters) measured diagonally. Other TV sets, small enough to fit in a pocket, have screens measuring about 3 inches (7.6 centimeters) diagonally.

Improvements in broadcasting and receiving equipment provide much clearer pictures than were available in the past. In early days, all programs were telecast in black and white. Color television began in 1953. Today most programs are telecast in color. More than 90 percent of American households have a color set.

At first, most telecasts were live productions or programs made from film. The film took time to develop. Also, the equipment and techniques used produced pictures and sounds of poor quality. Videotaping of programs began in the mid-1950's and became a major production method. Videotapes can be played back immediately after taping. They produce good quality pictures and sounds, and allow flexibility in program scheduling. Later, scientists developed equipment and techniques that improved the quality of filmed shows.

Early Bird, the first commercial communications satellite, was launched in 1965. Satellites made worldwide television broadcasting possible. Today, viewers can see such events as the Olympic Games as they happen.

Changes in programming. Television continues to be primarily a source of entertainment. But it also carries on its role of providing coverage of important events. For example, networks may cancel regular programs to cover a speech by the President.

Through the years, broadcasters generally avoided controversial themes, such as abortion, alcoholism, divorce, drug abuse, political satire, prejudice, and sex. They feared such themes would result in a loss of viewers. But in the late 1960's, broadcasters found that they could deal with controversial themes and still draw big audiences. The comedy show "Laugh-In" included many jokes about sex and much political satire, and it became the top-rated show of the late 1960's. "All in the Family," a situation comedy satirizing prejudice, gained top ratings in the early 1970's. "M*A*S*H," a popular situation comedy of the 1970's and early 1980's, satirized war. Such dramatic programs as "Little House on the Prairie" and "The Waltons" dealt with many moral and ethical problems. The success of such shows encouraged broadcasters to cover a wide range of topics.

Many people believe, however, that television has gone too far in its presentation of controversial themes. The amount of violence and sex on TV has especially drawn a great deal of criticism.

In the late 1970's, broadcasters began to present an increasing number of made-for-TV movies, serialized dramas called miniseries, and other special programs. The most popular such presentation was Roots, an eight-part drama tracing the history of an African American family from slavery to freedom.

In the late 1980's, the division between news and entertainment programs became less definite. Networks produced made-for-TV movies based on recent news events. Television news programs sometimes staged re-creations of news events when they did not have actual videotape recordings from the scene.

Recent developments. Videocassette recorders skyrocketed in popularity during the 1980's. Many viewers enjoyed renting pretaped movies and watching them at home. Also in the 1980's, satellites gained importance in distributing television programs to cable systems, broadcasting stations, and home subscribers.

In the early 1990's, new advances included high-definition television (HDTV), which produces very sharp pictures, and lightweight flat-panel television sets, which can be hung on a wall. For more information, see the Developments in television technology section of this article.

Contributor: V. Michael Bove, Jr., Ph.D., Associate Prof., Media Arts and Sciences Program, Massachusetts Institute of Technology., and Andrew B. Lippman, M.S., Associate Director, MIT Media Lab.

Related articles include:

Biographies
Hertz, Heinrich Rudolph

Equipment and physical principles
Electromagnetism; Electron Gun; Electronics; Frequency Modulation; Microphone; Radio; Speaker; Tape Recorder; Transistor.

What is a dissolve? A super? A wipe?

How did Vladimir K. Zworykin help develop TV?

Who was the first major television entertainer?

What career opportunities are available in television?

What are the methods of transmitting TV programs?

What are some negative impressions that people may form from watching a lot of television?

On what does the quality of a television picture depend?

Who regulates television broadcasting in the United States?

What are some specialized uses of television?

Cheney, Glenn A. Television in American Society. Watts, 1983.

Griffin-Beale, Christopher, and Gee, Robyn. TV & Video. EDC Pub., 1982.

Lambert, Mark. TV and Video Technology. Bookwright, 1990.

Barnouw, Erik. Tube of Plenty: The Evolution of American Television. Rev. ed. Oxford, 1990.

Brown, Les. Les Brown's Encyclopedia of Television. 3rd ed. Gale Research, 1992. Originally published in 1977 as New York Times Encyclopedia of Television.

Condry, John. The Psychology of Television. Erlbaum, 1989.

Winship, Michael. Television. Random Hse., 1988. Discusses the history and current trends of television.

Master Index