Film, Radio and TV - 23 |
Television --the Beginning
For thousands of people living some distance from the large cities even this kind of picture required the installation of a tall antenna next to their houses. Often, they could only get only one station -- and only then if atmospheric conditions were good. But, despite the difficulties, it was television, and it marked the beginning of a phenomenon that was to have a major impact on news, advertising, film, radio, and the world -- not to mention how millions of people would spend their leisure hours.
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Although television is blamed for everything from crime to tooth
decay, television has contributed many positive things to society, as we
will see when we explore this medium in the upcoming modules.
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But, let's start at the beginning. Inventions Leading to Television Discovering how to send audio through the airwaves opened the door to the possibility of television, but video was far more complex. It was correctly reasoned that since pictures had millions of times more data than audio, pictures would have to be broken down into bits of information (a data stream) before being transmitted. This was done by wrapping a photo around a drum, as shown on the right, and rotating the drum as a light-sensitive photocell moved over the image picking up brightness differences. The photocell created voltages that were amplified thousands of times and then sent by telephone lines to the subscribing newspapers. At the receiving end, somewhat the reverse took place. A piece of photographic paper spun around on a cylinder within a light-tight enclosure. The intensity of a pinpoint of light focused on the paper varied with the signal being picked up by the originating machine. When the scan was finished, the paper was taken out in a darkroom and processed as a photographic print. You may recall from an earlier module that experiments with film demonstrated that if a series of pictures were presented at a rate of about 16 or more per-second, an illusion of motion could be created. So the problem became one of electronically transmitting a series of still pictures every second. To do this the wirephoto approach of transmitting still photos -- which originally took about 20 minutes just to transmit
one picture -- would have to be speeded up millions of times.
Who Invented TV? Early approaches were based on mechanical devices using a kind of Even with the obvious limitations, some TV transmitters went on the air using mechanical approaches. In the United States, four people are given credit for major inventions leading to television: Philo T. Farnsworth, Allen B. DuMont, Charles Jenkins, and Vladimir K. Zworykin. Philo T. Farnsworth, an American engineer, who is most associated with the invention of TV, rejected the mechanical approach and decided that the only thing fast enough to scan a moving image was a stream of electrons. In 1926, he was trying to construct a TV receiver in the dining room of his Hollywood, California apartment. According to his wife, although constant "pops," "sizzles" and "bangs" came from the experimental TV equipment, these were not as bad as the terrible acidic smell that filled their apartment.
Farnsworth not only had problems with his wife. Since he had the blinds pulled on his house during the day (to better see the experimental TV sets), the neighbors and police reasoned that he must have been doing something illegal -- probably brewing alcohol. They raided his apartment, and, although mystified by what they saw, at least they didn't throw him in jail. In the close-up of a black and white TV screen on the right you can see the individual lines that comprise this type of TV picture. This scanning approach is still used today, although with today's color systems the scanning process results in millions of illuminated colored dots.
Once the problem of how to dissect images and sequentially transmit them through the air by means of radio waves was solved, we had the central elements of the television equation. The television process is explained more fully
Television Officially Launched by RCA But, since there still weren't many TV sets in existence, most of the audience was watching the show at the Fair. The first TV receivers had 13 cm (5 inch) screens and black and white pictures. They cost about half the price of an automobile. Before long, six TV stations were on the air in the U.S., and many more were in development.
On July 1st, 1942, CBS launched 15 hours of weekly programming, including two 15-minute, Monday through Friday newscasts. The TV news was simply read from a script, radio style, by an announcer in a small announce booth. A single camera was aimed through the window of the booth. Also on July 1st, an NBC station broadcast the Dodger-Phillie baseball game -- complete with a Bulova watch commercial (TV's first commercial). The people who had seen TV were mesmerized by what they saw, and television was poised to immediately take off. But, it was not to be -- not just yet.  In the next module we'll trace the development of television into its "golden age."
A website that focuses on the history of television can be
 found here.
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concept was wirephotos (using telephone lines to send still photos to newspapers).
moving peephole that focused light reflected from a scene on a photocell. Although these devices worked, they were big, heavy, cumbersome, and of low resolution (producing limited detail). One of the first TV images of this type is the famous Felix the cat image shown here.
of electrons to "read out" brightness information on a line-by-line basis from the backside of an image focused on a light-sensitive area of a tube.
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