Historical Review, Invention of Television

In the word Television Tele-” is a prefix that means “far off” or “operating at a distance.”  The word "television" was agreed upon quite rapidly, and while other terms like "iconoscope" and "emitron" referred to patented devices that were used in some electronic television systems, television is the one that stuck.

A television basically consists of three parts: the TV camera that turns a picture and sound into a signal;  the TV transmitter that sends the signal through the air;  and the TV receiver (the TV set in the home) that captures the signal and turns it back into picture and sound.  TV creates moving pictures by repeatedly capturing still pictures and presenting these frames to your eyes quickly that they seem to be moving.  The images are flickering on the screen so fast that they fuse together in your brain to make a moving picture.

Earlier televisions were monochrome mono means single and chrome means colour, having single colour known as black and white televisions.

Historical review

No single inventor deserves credit for the television.  The idea was floating around long before the technology existed to make it happen, and many scientists and engineers made contributions that built on each other to eventually produce what we know as TV today.

Television's origins can be traced to the 1830s and '40s, when Samuel F.B.  Morse developed the telegraph, the system of sending messages (translated into beeping sounds) along wires.  Another important step forward came in 1876 in the form of Alexander Graham Bell's telephone, which allowed the human voice to travel through wires over long distances.

Both Bell and Thomas Edison speculated about the possibility of telephone-like devices that could transmit images as well as sounds.  But it was a German researcher who took the next important step towards developing the technology that made television possible.  In 1884, Paul Nipkow came up with a system of sending images through wires via spinning discs.  He called it the electric telescope, but it was essentially an early form of mechanical television.

The word "television" first appeared in 1907 in the discussion of a theoretical device that transported images across telegraph or telephone wires.  Ironically, this prediction was behind the times, as some of the first experiments into television used radio waves from the beginning.

TV Goes Electronic With Cathode Ray Tubes

In the early 1900s, both Russian physicist Boris Rosing and Scottish engineer Alan Archibald Campbell-Swinton worked independently to improve on Nipkow's system by replacing the spinning discs with cathode ray tubes, a technology developed earlier by German physicist Karl Braun.  Swinton's system, which placed cathode ray tubes inside the camera that sent a picture, as well as inside the receiver, was essentially the earliest all-electronic television system.

Russian-born engineer Vladimir Zworykin had worked as Rosing's assistant before both of them emigrated following the Russian Revolution.  In 1923, Zworykin was employed at the Pittsburgh-based manufacturing company Westinghouse when he applied for his first television patent, for the “Iconoscope,” which used cathode ray tubes to transmit images.

 Meanwhile, Scottish engineer John Baird gave the world's first demonstration of true television before 50 scientists in central London in 1927. With his new invention, Baird formed the Baird Television Development Company, and in 1928 it achieved the first transatlantic television transmission between London and New York and the first transmission to a ship in the mid-Atlantic.  Baird is also credited with giving the first demonstration of both color and stereoscopic television.

Earlier television shows were in monochrome, but with advancements in technology, they also started coming in colored versions. And remote control invented later for more convinece. By clicking on link You can read the articles colour television and invention of remote control in detail.

Continue

Historical Review, Invention of Colour Television

Earlier television were in monochrome, but with advancements in technology, they also started coming in colored versions.

Colour Television in 19th  century 

Colour television was by no means a new idea.  In the late 19th century a Russian scientist by the name of A.A.  Polumordvinov devised a system of spinning Nipkow disks and concentric cylinders with slits covered by red, green, and blue filters.  But he was far ahead of the technology of the day;  even the most basic black-and-white television was decades away.  In 1928, Baird gave demonstrations in London of a color system using a Nipkow disk with three spirals of 30 apertures, one spiral for each primary color in sequence.  The light source at the receiver was composed of two Cathode ray tubes or gas-discharge tubes, one of mercury vapor and helium for the green and blue colors and a neon tube for red.  The quality, however, was quite poor.

Colour Television in 20th century 

In the early 20th century, many inventors designed color systems and their basic concept was later called the "sequential" system, different terminologies used as more and more new functions introduced. They introduce three successive coloured filter red, blue, and green to scane the picture. Idea was that in the result out put human eye would see original multicoloured.

Unfortunately, this system required too fast a rate of scanning which were not possible in black-and-white receivers would not be able to reproduce the pictures.  Sequential systems therefore came to be described as "noncompatible."

An alternative approach which is compatible with existing black and white recovers known as “simultaneous” system, which would transmit the three primary-colour signals together.

In 1924, Harold McCreary designed a system using cathode-ray tubes as camera speratly to scane each of three primary colour components of picture at receiving end. In each tube,  elecron struck the phosphors coated screen In the result glow of appropriate three primary Colour produced, series of mirrors would then combine these images into one picture.

At that time this was a new idea but not working properly .

In 1929 Herbert Ives and colleagues at Bell Laboratories transmitted 50-line colour television images between New York City and Washington, D.C.; this was a mechanical method, using spinning disks, but one that sent the three primary colour signals simultaneously over three separate circuits.

After World War II, the Columbia Broadcasting System (CBS) began demonstrating its own sequential color system, designed by Peter Goldmark.  Combining cathode-ray tubes with spinning wheels of red, blue, and green filters, it was impressive enough that's why Federal Communications Commission (FCC) to authorize the Goldmark system for commercial television, but Sarnoff warned against using a "horse-and-buggy" system that was incompatible with monochrome TV.  At the same time, Sarnoff whipped his troops at RCA into developing the first all-electronic compatible color system in 1950.

In this every 1/60 of a second the receiver’s three electron guns painted the entire picture simultaneously with red, green, and blue, left to right, line by line.

And the RCA colour system was compatible with existing black-and-white sets.

In 1952, the National Television Systems Committee (NTSC) was reformed, this time with the purpose of creating an "Industry Color System." Which adopted most of Europe and Japan as well. And after this varity of different colours and system like PAL (phase alternation line) introduce in Germany the United Kingdom, and the rest of Europe had adopted PAL. In France Henri de France developed SECAM Soviet Union adopted SECAM, both these system are based on NTSC system with slitly modifications, These are still the standards of colour television today, despite the arrival of digital television.

With the passage of time different name were given according to modifications of system three colour system then multi coloured and digital television now a days smart television like LCD and LED with high resolution advance futures and systems.

Digital television 

Digital television technology emerged to public view in the 1990s.  In the United States professional action was spurred by a demonstration in 1987 of a new analog high-definition television (HDTV) system by NHK, Japan's public television network.  This incited the FCC to declare an open competition to create American HDTV, and in June 1990 the General Instrument Corporation (GI) surprised the industry by announcing the world's first all-digital television system.  Designed by the Korean-born engineer Woo Paik, the GI system displayed a 1,080-line color picture on a wide-screen receiver and managed to transmit the necessary information for this picture over a conventional television channel.  Heretofore, the main obstacle to producing digital TV had been the problem of bandwidth. 

Within a few months of GI's announcement, both the Zenith Electronics Corporation and the David Sarnoff Research Center (formerly RCA Laboratories) announced their own digital HDTV systems.

In 1993 these and four other TV laboratories formed a "Grand Alliance" to develop marketable HDTV.  In the meantime, an entire range of new possibilities aside from HDTV emerged.  Digital broadcasters could certainly show a high-definition picture over a regular six-megahertz channel, but they might "multicast" instead, transmitting five or six digital standard-definition programs over that same channel.

Indeed, digital transmission made “smart TV” a real possibility, where the home receiver might become a computer in its own right. 

There are varity of smart television like LCD and LED available in market with high resolution advance futures and systems.

Continue