| | Televizyonun icadı - ingilizce
Televizyonun icadı - ingilizce
Thu, 09/11/2008 11:00 Bill Schnarr
Although traditional thinking tells us that mans best friend has always been the dog, common thinking has been that in the last century man has quietly become infatuated with a new best friendnamely, that square thing in his living room.
But where did the television come from? Although these days, you would be hard pressed to find a house without at least one television set in it, it may surprise you to know that even up to the 1970s televisions were considered something of a luxury and not the necessity that they have become today.
It all began with some very bright minds at the beginning of the last century.
But, even as bright as they were, not even they could imagine just how important their early attempts at picture transmissions would be.
The Early Innovators
Historians agree that television came into being with the advent of Nipkows Disk in 1884. Although the device was ultimately a failure, it paved the way for many later inventions.
Paul Nipkow invented a scanning system that made use of a rotating disk with a row of small holes in it. When the disk rotated, the holes, or apertures, measured the amount of light they were receiving and could send that information to another disk to be processed back into an image.
It was crude and lacked power, but it was a start. Nipkows device could essentially record and transmit a black and white silhouette of an image placed in front of it and reproduce that image on another machine.
Nipkows disk demonstrated the premise for dissecting an image into basic elements that could be sent over a wire to another machine. This idea proved to be the basic television scanning technology still in use by televisions today.
Nipkows device laid the groundwork for television technology development at the time. A few years later it would be the work of two men, Philo Farnsworth and Vladimir Zworykin, who took Nipkows work and ran with it.
A popular myth about Philo Farnsworth says that he originally dreamed up the idea of the television set when he was only fifteen years old. Whether that is true or not is now for historians to debate, but whatever the case it was apparent that from a very early age Farnsworth was a young man with some very big ideas.
At the age of 19 Farnsworth met a financial expert by the name of George Everson. Farnsworth needed Everson to secure capital for his new ideaan all-electric television set. After setting up shop in California, he quickly secured several important patents on his technology.
Among the patents in particular, was a patent for linear sweep, an important factor in the development of televisions scanning properties. In 1927 he gave the first public demonstration of his new device.
He wasnt even 21 years old!
In 1928, Farnsworth developed a device he called an Image Dissector. The Image Dissector was an electronic pickup and scanning device that used a stationary aperture to collect electrons from a charged image and recreate the image based on the charge of the photocathode at a given moment.
Essentially, based on the charge it collected, the device was able to recreate an image placed in front if it. It was an important step in the development of signal transfer for television devices.
However, because of the large amount of light needed to activate the electrons and the fact that the device lacked any recording ability (thus making only instantaneous transmission possible) it was relegated to being used as a laboratory signal.
Farnsworths original demonstration in 1928 included several graphic images, film clips from a Dempsey/Tunney fight and some scenes of Mary Pickford combing her hair from The Taming of the Shrew. This demonstration showed the world what the future of television held in store and set in motion the first wheels of the television industry.
Shortly thereafter, Farnsworth met a man named Vladimir Zworykin.
A Russian immigrant who arrived on the shores of America after World War 1, Vladimir Zworykin came across the ocean to develop his greatest dreamtelevision.
He settled in Pittsburgh, and from 1920-1929 he performed many television-related experiments for a company called Westinghouse.
Among his developments in the field, the most important ones are considered to be the Iconoscope, the first television camera tube, and the Kinescope cathode ray tube. Many people believe that because of these inventions Zworykin is the father of the modern television.
The Iconoscope was named after the Greek terms of image and to see. It was comprised of an aluminium-oxide film and an aluminium film coated with a layer of photosensitive potassium hydride. Using the Iconoscope as a camera and the CRT (cathode ray tube) as an image receptor, Zworykin created the essential elements for an electronic television.
Later, in 1929, Zworykin improved on his CRT design and presented his findings to the Institute of Radio Engineers. There he attracted the attention of David Sarnoff, a fellow Soviet immigrant who promptly made Zworykin head of the electronic research laboratory for a company known as RCA.
By 1931 Zworykin had tweaked the Iconoscope and CRT to the point where they were ready to launch their invention upon the world.
The television industry was about to be born.
Television officially went on the air in July of 1941 when the Federal Communications Commission (FCC) authorized the first two television stations to be built in the United States. At the end of World War Two in 1945, there were nine licensed stations with six of them actually on the air.
It became a fashion statement to have television antennas on the roof of your home. The number of television sets on the market exploded, and the fledgling industry was off and running.
As popular as television was, however, nobody who was involved in the design of them thought that they would be as popular as they became. Most designers believed the UHF format of 12 channels would be more than enough for society.
How little they knew.
The first UHF transmissions went on the air in 1953. Before that, there were no channels for television; one simply turned it on and watched whatever they could pick up in their area.
The UHF format allowed broadcast companies to broadcast their commercial programs on a specific wavelength, or frequency. As early televisions had no means of switching between these frequencies, converter boxes quickly became the norm. The first boxes were tuned only to single frequencies but were soon replaced by multi-frequency switchers.
Eventually, the FCC issued a mandate that all new televisions built would contain a UHF switching device, making their broadcast system more stable and usable by all.
This format was cemented with the use of a special device known as a Klystron. A klystron is a device capable of sending out high-powered UHF signals.
It also happened to be an integral part of the Allied war effort in World War Two when it was used with the British Magnetron device to develop smaller, more reliable Doppler radar devices.
It was these radar devices that won the battle of Britain, and ultimately, the war in Europe.
Reality Goes Colour
Although first developed as early of the 1920s, colour television made a long and rather sordid trip before becoming a common household item.
The first big push for a reliable colour system was by Peter Goldmark at CBS in the early 1940s. The device, known as a field sequential system, or colour filter wheel system, was incompatible with existing television receivers, had limited picture size capabilities, and was mechanically noisy. However, in 1950 the FCC adopted it as the national colour standard. The engineering community was not amused.
In 1950, monochrome (black and white) television was three years old and had a viewing base of 15 million people nationally. With the incompatible colour system pushed by CBS and backed by the FCC, television broadcasters were faced with the problem of all of their equipment suddenly becoming obsolete.
Many had wished for a colour system that was compatible with the monochrome system for simultaneous broadcasting, and some even felt that CBS had conspired with the FCC for their own political ends.
Colour broadcasting began on a 5 station East Coast network on June 21, 1951. Colour/Monochrome receivers went on sale in September of that year, but they were an abysmal failure. They sold 100 sets before ceasing their broadcast in October, and in November the NPA (National Production Authority) imposed a prohibition on colour television sets being sold to the general public. Again, this was interpreted by some as an effort to get CBS off the hook and out of the colour game.
In 1953 CBS came up with another system for colour that involved applying phosphor dots to a television faceplate with a curved shadow mask. This allowed for transmission to either colour or monochrome sets with the same signal and was quickly adopted by the FCC as the national colour standard.
A short time later, reality officially began broadcasting in colour.
Television Grows Up
Television quietly grew up during the 1980s with the advent of High Definition Television and Surround Sound technology. Unfortunately, because no one could agree on how best to format these technologies for public consumption, there was no one around to celebrate it.
In November of 1987, 58 U.S. broadcasters requested that the FCC make a ruling on advanced television services. What the broadcasters wanted to know was whether they would be permitted to broadcast HDTV on the existing television spectrum, or if another source could be used as an alternative to traditional broadcasting.
Broadcasting organizations feared that an alternative delivery of broadcast media would creep in to challenge them for their space. It appeared to be the old colour argument all over again.
Additionally, television broadcasters have been in a long fight with radio broadcasters over the amount of spectrum available for broadcast. While television broadcasters began looking at expanded television signals as a way to deliver HDTV to customers, radio broadcasters were also fighting for more spectrum space.
This argument has caused the FCC to be very careful about how it treats the situation.
As high definition digital tv came of age in the early part of the last century and has continued to develop even today, it has been a mandate by the FCC and others to protect consumers at every step of the way.
The arguments and problems arise not when a new technology pops up, but when that technology threatens to undermine the confidence of television consumers. Few people are willing to spend thousands of dollars on new equipment only to have it rendered obsolete a few years down the road.
This in turn has caused broadcast and development companies to tightly control how the television industry is run. A missed opportunity to enhance the system could cause billions in lost profits for all, while at the same time adding services at the expense of others can cause an equally staggering loss in profits.
The general thinking these days is that any advancement in technology or service must be tempered with the ability to provide continued service to even the lowliest broadcasters and television owners, from theatre screen HDTV satellite subscribers all the way down to the person who owns an old monochrome transmission receiver.
In the eyes of the television industry, every one of them is a potential source of revenue.