Light and Sound in Communication
(TV) is a major communication tool in today’s world. It is based on the very fundamental principle of science that energy can change forms. Sound and light are both forms of energy that are converted into electrical waves and transmitted across the globe as radio waves or signals. Radio waves carry TV signals efficiently, with low interference. Such waves have a long range and can penetrate structures like walls and buildings.
The signals are captured by appropriate devices and converted back into sound and light forms by the TV set. That's how we are able to see and hear events taking place at distant places on a 'live' basis. The same mechanism enables video calls on Skype and OOVOO platforms.
Televising or telecast requires a transmitter, a receiver and a display device with sound speakers as the basic components. Video and audio sources provide the content such as a TV show, news program, live feed or movie. The video and audio sources are usually pre-recorded.( Source- Wikipedia)
All major broadcasting agencies use their own transmitters, usually terrestrial transmission towers. The transmitter is necessary for broadcasting signals over the airwaves to viewers in their area. The electrical signals are transformed into radio waves, which are picked up, if free to air, by our TV sets (which has in-built receivers) or by receivers installed by Cable TV operators, who, in turn, provide the feed to our TV sets. Satellite TV with Direct to Home (DTH) signals are also available.
A transmitter typically telecasts a number of different channels, out of which viewers can choose what they want to see & hear.
A display device can either be a TV set or a monitor. The display device turns electrical signals into viewable images. TV sets used to have cathode ray tubes (CRT) in the past to project images. Display devices now include liquid crystal display (LCD), gas charged display (plasma) and High Definition (HDD) devices. (Source – How stuffs work)
The display device is usually equipped with speakers as well. Audio signals need to match up with videos being shown. Output can also be sent to high quality sound systems to improve the audio experience. (Source – How stuffs work)
Broadcast TV signals are mostly free to air. They can be picked up by anyone, using a receiver. Signals can be transmitted on a range of radio frequencies (RF). Federal Communications Commission (FCC) of the USA has allocated 6 MHz of bandwidth for each TV channel, which can be on any one of the 3 bands, namely, Bands III, IV or V. Band-wise channel distribution is given below:
Channels 2 to 13 carry Very High Frequency (VHF) signals, whereas Ultra High Frequencies (UHF) channels usually cover channels 14 to 83. (Source- TelevisionBroadcast.com )
Satellite TV carries out transmission through transponders fixed on earth orbiting satellites and not terrestrial towers. Satellite signals, usually digital, are encrypted and compressed and therefore require special antennas, properly aligned, to pick up specific satellite signals.
As these signals need to be decoded and decompressed to view on a TV set, they require special equipment.
Cable TV is a popular channel for delivery of entertainment content. The cable TV operator collects the signals from a central point for onward supply to our homes via copper or fibre optic cables laid out for the purpose. The signals are usually encoded or compressed. Viewers require technical devices to unscramble and decompress the signals so as to view the content on their TV sets.
Ever since TV technology was invented, it has undergone many improvements. The old TV sets all had vacuum tubes called Cathode Ray Tubes (CRT), inside which electrons moved rapidly from one field to another (negative to positive) and streamed onto a screen that was coated with phosphor. Phosphor glowed when these electrons hit the screen, resulting in formation of images.
TV form images by creating small dots, called pixels, on the screen. The more pixels there are on the screen the better is the video quality. (Source- TVTechnology.com )
Colour & Clarity
CRT technology further developed and started having three beams instead of one beam used in black and white TV sets. Colour TVs have red, blue and green beams, with three sheets of phosphor (red, blue and green) behind the TV screen. With this, TV became colourful and more real.
TV technology has made further advances by using LCD, Plasma, HDD and other complex technologies and other image & sound enhancing devices, which give almost real life distortion free picture and sound quality.
Television was invented in the early 1900’s and, in a few decades, it was all over the developed world. The device gradually spread to developing countries in Asia and Africa, with the support of their respective national governments. Initially, TV was viewed as a means of disseminating information and news to the public. Channels were generally free to air. Entertainment content was limited. Now it is difficult to imagine life without TV. TV channels have mushroomed. Satellite and Cable TV further add to the variety. Programme guides have been on offer to help viewers choose their programmes. The first and foremost impact is almost instant telecasting of news and developments taking place in any part of the world to the rest of the world. 24 hour news channels dish out all kinds of news all the time. Mass media has become really important due to such channels. However, it has become difficult for viewers to judge which channel is truthful. In wartimes, the practice of ‘embedding’ TV reporters to war fronts can give us a distorted picture.
By watching movies, we also get to know the culture of other countries. This has powered globalisation. People in different countries are now freely adopting cultural practices and lifestyles displayed on TV. Globalisation is good for the mankind as it opens up new opportunities, but at times it can also lead to cultural conflicts in conservative societies. There is also a feeling that the powerful TV media is often misused to broadcast ill-informed opinions and views of some people.
Sitcoms and movies are great sources of entertainment at home. But they also make us lazy. Many a time people neglect their work to watch TV programmes. This can be very harmful for students. Too much of watching TV is known to make young boys and girls lazy and fat.
On the whole, TV is a powerful social media for communication. It can bring all the news, views and entertainment to your doorsteps from all over the world. Interactive TV also helps viewers exercise active control of what they are watching. But, in a society that is not democratic, it can also be used to spread political doctrines or the ‘right’ culture. So it is politically sensitive. (Source- wowessays)
Bits, Top . "How Television Works." TopBits. N.p., n.d. Web. 5 May 2010. <http://www.topbits.com/how-television-works.html>.
essays, Wow. "Telivison." wowessays. N.p., n.d. Web. 5 May 2010. <www.wowessays.com/dbase/af4/crs241.shtm l>.
.org, Wikipedia. "Technology of television - Wikipedia, the free encyclopedia." Wikipedia, the free encyclopedia. N.p., n.d. Web. 5 May 2010. http://en.wikipedia.org/wiki/Technology_of_television
Lung, Doug. "TVTechnology.com - HD, Antenna TV, Broadband, 3dTV, Engineering, Audio Transmission & Reception." TVTechnology.com - HD, Antenna TV, Broadband, 3dTV, Engineering, Audio Transmission & Reception. N.p., n.d. Web. 5 May 2010. <http://www.tvtechnology.com/
Unknown, Unknown. "Howstuffworks "TV Technology"." Howstuffworks "Electronics". N.p., n.d. Web. 5 May 2010. <http://electronics.howstuffworks.com/tv-technology.htm>.
"TelevisionBroadcast.com | TVB | 3DTV | Broadcasting | Digital | Broadcast | Television | DTV |." TelevisionBroadcast.com | TVB | 3DTV | Broadcasting | Digital | Broadcast | Television | DTV |. N.p., n.d. Web. 5 May 2010. <http://www.televisionbroadcast