The History Of Television

By Author: Robert Gordon
Total Articles: 4
Comment this article

Thanks to technology, the development of televisions has come a long way. Once only used for public announcements and only displayed in black and white, TVs have made an incredible transformation.

Dell tvs are now available in Plasma TVs, LED HDTVs, LCD HDTVs and display hundreds of channels. The usages and capabilities of TVs have changed tremendously over the years.

Televisions are defined as telecommunication mediums used for transmitting and receiving moving images that can be black-and-white or colored, and can be accompanied with or without sound.

TVs have been commercially available since the late 1920s. They have become extremely common in homes, businesses and institutions. Not only are they used for sources of news, but they're also used as a vehicle for advertising and provide entertainment. Since the 1970s, TVs have been used to view recorded as well as broadcast material. There has even been a recent rise in Internet television available via the Internet ...
... through sources such as iPlayer and Hulu.

The most common usage of a TV is for broadcasting television, which was modeled on the existing radio broadcasting systems developed in the 1920s. It uses high-powered radio-frequency transmitters to broadcast the television signal to individual TV receivers.

The first electromechanical television system was patented in 1884 by Paul Gottlieb Nipkow, a 23-year-old university student in Germany. The patent utilized a scanning disk and a spinning disk with a series of holes spiraling toward the center, for rasterization. The holes were equally spaced at angular intervals so that the disk would allow light to pass through every hole and onto a light-sensitive selenium sensor in a single rotation, which produced the electrical pulses. While an image was focused on the rotating disk, every hole obtained a horizontal slice of the complete image.

The design did not become practical until advances in amplifier tube technology were made available. The device was only useful when it came to transmitting still halftone images, which were represented by equally spaced dots of varying size, over telegraph or telephone lines. Future designs employed a rotating mirror-drum scanner to attain the image and a cathode ray tube (CRT) as a display device. However, moving images were still not possible because of the poor sensitivity of the selenium sensors.

In 1907, Boris Rosing became the first inventor to use a CRT in the receiver of an experimental television system. The Russian scientist used mirror-drum scanning to transmit simple geometric shapes to the CRT.

Scottish inventor John Logie Baird succeeded in demonstrating the transmission of moving silhouette images in London in 1925 by using a Nipkow disk. He used the technology to move monochromatic images in 1926. The scanning disk produced an image of 30 lines resolution, which was enough to distinguish a human face. Baird's demonstration is said to be the world's first true demonstration of television.

Broadcast TV programs were previously transmitted as an analog television signal, but in 2008 the U.S. went almost exclusively digital. A typical television set includes multiple internal electronic circuits, along with those for receiving and decoding broadcast signals. A TV system can use different technical standards like digital television (DTV) and high-definition television (HDTV). TV systems are now also used for surveillance, industrial process control and even the guiding of weapons in places where direct observation is impaired.

TVs have come a long way. With the constant development of technology, there are sure to be quite a few changes in the upcoming years.