|
|
|
|
|
|
Lesson#32
|
TELEVISION – A NEW DIMENSION IN MASS
COMMUNICATION
|
|
|
|
TELEVISION – A NEW DIMENSION IN MASS COMMUNICATION
Television is the process of capturing photographic images,
converting them into electrical
impulses, and then transmitting the signal to a decoding
receiver. Conventional transmission is by means of
electromagnetic radiation, using the methods of radio.
Among the technical developments that have come to dominate our
lives, television is surely one of the top
few. In the developed world, the average household watches
television for seven hours per day, which
helps to explain why news, sports, and educational entities, as
well as advertisers, value the device for
communication.
The device we call the television is really an image and sound
receiver that is the end point of a broadcast
system that starts with a television camera or transmitter and
requires a complicated network of transmitters
using ground-based towers, cables, and satellites to deliver the
original picture to our living rooms.
TV came like a bang as the time distance between the invention
of radio and television is not much. People
across the world were still amazed by the presence of radio in
their lives that within years they were having a
device which also showed images with sound – a great fun indeed.
How it started?
The electronic way of communication was quite well know by the
start of the 20th
century but in
almost all cases it was limit to sending or receiving voice
messages. Since most researchers and scientists
were focusing on the voice transmission, the radio broadcast
resulted almost simultaneously in many parts
of the world with the exception of a difference of few years.
The name of Marconi, however, stands
distinguished in the eyes of many as the inventor of radio.
The inventor of television, the device responsible for receiving
voice as well as images, is John Logie Baird
of Scotland. But obviously the new invention has been the result
of the extensive work done by scores of
other scientists as well. The development of the television
occurred over a number of years, in many
countries, and using a wide application of sciences, including
electricity, mechanical engineering,
electromagnetism, sound technology, and electrochemistry. No
single person invented the television;
instead, it is a compilation of inventions perfected by fierce
competition.
Early Discoveries
Chemicals that are conductors of electricity were among the
first discoveries leading to the TV.
Baron Ȯns
Berzelius of Sweden isolated selenium in 1817, and Louis May of Great Britain
discovered, in
1873, that the element is a strong electrical conductor. Sir
William Crookes invented the cathode ray tube in
1878, but these discoveries took many years to merge into the
common ground of television.
Paul Nipkow of Germany made the first crude television in 1884.
His mechanical system used a scanning
disk with small holes to pick up image fragments and imprint
them on a light-sensitive selenium tube. A
receiver reassembled the picture. In 1888, W. Hallwachs applied
photoelectric cells in cameras; cathode rays
were demonstrated as devices for reassembling the image at the
receiver by Boris Rosing of Russia and A.
A. Campbell-Swinton of Great Britain, both working independently
in 1907. Countless radio pioneers
including Thomas Edison invented methods of broadcasting
television signals.
Although Logie Baird had been developing his own methods of
televised images for many years it was in
1924 that he first demonstrated a mechanically scanned
television system which transmitted objects in
outline and went on the following year to show the head of a
dummy, not just in outline but as a real image.
First Pictures were shown on Sept 7, 1927.
TV changes some basic concepts
TV is largely responsible for bringing about so many social,
cultural and economic changes- and
that too with rapid speed, and is considered as one major factor
to help globalize human thinking and
understanding on various matters by fully exploiting all the
elements possible in visual communication, or
say broadcasting. More on this aspect will be discussed in a
coming lecture.
108
By 1935, mechanical systems for transmitting black-and-white
images were replaced completely by
electronic methods that could generate hundreds of horizontal
bands at 30 frames per second. Vladimir K.
Zworykin, a Russian immigrant who first worked for Westinghouse,
patented an electronic camera tube
based on the cathode tube. Philo T. Farnsworth and Allen B.
Dumont, both Americans, developed a pickup
tube that became the home television receiver by 1939.
From Black and White to color
The Columbia Broadcasting System (CBS) had entered the color TV
fray and battled with RCA to
perfect color television, initially with mechanical methods
until an all-electronic color system could be
developed. Rival broadcasts appeared throughout the 1940s
although progress was slowed by both World
War II and the Korean War. The first CBS color broadcast on June
25, 1951, featured Ed Sullivan and
other stars of the network.
Commercial color television broadcasts were underway in the
United States by 1954.
In December of 1954, RCA introduced their 21" color TV. Although
the number recorded in history
books is 5,000 units sold, the common belief (amongst
collectors) is that the actual number sold to the
public was considerably less.
1950-1959 was an exciting time period for television. In the
USA, B&W television exploded onto the scene
at the beginning of the decade, mid-decade saw electronic color
television and remote controls launched,
and at the end of the decade the public witnessed some
interesting styling changes and the introduction of
transistorized television.
II World War
The sudden outbreak of WW2 halted to some extent progress on TV
transmissions and
improvement in technological advancement in making TV a
household item for most. The B/W limited
scale TV transmission continued to excite people. The images of
war ridden and ravaged sites on mini
screens of old-fashioned TV sets would pull crowd to watch those
and get influenced by the devastation of
the mad war. Seeing is believing, worked to make people
understand as who was winning the war and who
was controlling the known cities at different stages of the
years long fighting. It was a sight not to be
forgotten for those who first witnessed defeat of German armies
at different fronts and marching of the
allied forces on the German land towards the last days of the
war.
TV Programs
TV program pattern remained like the ones seen on radio
broadcast. Classification of its
transmission has been made in the following manner.
News
Music
Films
Comedy shows
Live shows
Sports
There are currently 3
main television transmission standards
used throughout the world:
NTSC - National
Television Standards Committee. The oldest existing standard, developed in the
USA.
First used in 1954. Consists of 525 horizontal lines of display
and 60 vertical lines.
SECAM - Système
Électronique pour Couleur avec Mémoire. Developed in France. First used in 1967.
A
625-line vertical, 50-line horizontal display.
PAL - Phase
Alternating Line. Developed by German engineer Walter Bruch who patented his
invention
1963 and the first commercial application of the PAL system was
in August 1967. Also a 625/50-line
display and alternative of NTSC. Proponents call it
"Perfection
At
Last."
109
Broadcast, Cable, and Satellite Television Transmission
Television programs may be transmitted either “live” or from a
recording. The principle means of
recording television programs for future use is videotape
recording. Videotape recording is similar to
conventional tape recording .The sound is recorded along with
the video signal on the same tape.
When a television program is broadcast, the varying electrical
signals are then amplified and used to
modulate a carrier wave the modulated carrier is usually fed to
an antenna, where it is converted to
electromagnetic waves and broadcast over a large region. The
waves are sensed by antennas connected to
television receivers.
The range of waves suitable for radio and television
transmission is divided into channels, which are
assigned to broadcast companies or services.
Most television viewers across the world no longer receive
signals by using antennas; instead, they receive
programming via cable television. Cable delivery of television
started as a way to improve reception. A
single, well-placed community antenna received the broadcast
signals and distributed them over coaxial or
fiber-optic cables to areas that otherwise would not be able to
receive them. Today, cable television is
popular because of the wide variety of programming it can
deliver. Many systems now provide more than
100 channels of programming. Typically, a cable television
company receives signals relayed from a
communications satellite and sends those signals to its
subscribers.
The first transatlantic television broadcast was accomplished by
such a satellite, called Telstar, on July 10,
1962. Some television viewers use small satellite dishes to
receive signals directly from satellites. Most
satellite-delivered signals are scrambled and require a special
decoder to receive them clearly.
The Future
The future of television seems bright. More research is going
into this process. High Definition
Television (HDTV) was developed by the Japanese Broadcast
Corporation and first demonstrated in 1982.
This system produces a movie-quality picture by using a
1,125-line picture on a "letter-box" format screen
with a 16 to nine width to height ratio. High-quality, flat
screens suitable for HDTV, are being perfected
using synthetic diamond film to emit electrons in the first
application of synthetic diamonds in electronic
components.
Other developments in the receiver include gold-plated jacks, an
internal polarity switch on large screens
that compensates for the effect of Earth's magnetic field on
image reception, accessories to eliminate ghosts
on the screen. Liquid crystal display (LCD) technology is also
advancing rapidly as an alternative to the
cumbersome television screen. Assorted computer chips add
functions like channel labeling, time and data
displays, swap and freeze motions, parental channel control,
touch screens, and a range of channel-surfing
options.
Digital television of the future will allow the viewer to
manipulate the angle of the camera, communicate
with the sports commentator, and merge and edit movies on
screen. Two-way TV will also be possible.
Current screens may be used thanks to converter boxes that
change the analog signal that presently
energizes the phosphors on the back of your television screen to
digital signals that are subject to less
distortion—and are the language of computers. Computer
technology will then allow a world of
manipulation of the data as well as broadcast of six times as
much data. |
|
|
|
|
|
|
