Radio Communication Presentation. Work for Tech 1002.

1. Radio Communication and the Mobile Phone By Daniel Williams

2. Introduction This short presentation will explain and describe key points of: Radio Waves Radio communication using amplitude modulation (AM) How a mobile phone network uses radio communication

3. History Although the concept and creation of mobile telephones, is one that is new to our modern day society, the use of radio communications has been extremely relevant in the western world for well over a hundred years now.

4. Who was behind it? There is still a lot of confusion and uncertainty to who is behind the creation of radio communication but the two men who are seen to be the fathers of radio communication are Tesla and Marconi. Guglielmo Marconi was the first person to create a radio signal that crossed the Atlantic. This was seen as a measure that made radio waves a significant way of communication. Nikola Tesla was the first person to develop a way of transmitting radio signals.

5. What are Radio Waves? Radio waves have the longest wavelengths in the electromagnetic spectrum. These waves can be longer than a football field or as short as a football. Radio waves do more than just bring music to your radio. They also carry signals for your television and cellular phones.

6. Amplitude Modulation(AM) Carrier Waves are send and can communicate basic signals such as Morse Code. If you want to add addition information to a wave such as speech or computer data, a process called modulation is used Modulation involves a certain feature either the amplitude (in the case of AM) or frequency (in the case of FM) being varied in the radio signal. For amplitude modulation transmission, the electrical signal from a microphone produced by speech is used to fluctuate the amplitude of the carrier wave, so that at any instant the size or amplitude of the carrier wave is made proportional to the size of the electrical modulating signal.

8. Frequencies Different media types use different frequencies so that the signals are not overlapped and interrupted. AM Radio Frequencies range form 180 kHz to 1.6 MHz. FM Radio Frequencies range form88kHz to 108 MHz. TV signals range from 470 to 854 MHz. Mobile Phone signals range from 872-960 MHz, 1710-1875 MHz and 1920 - 2170 MHz.

9. Mobile Phones Radio Communication is used to send and receive information through mobile phone. Radio frequency signals are transmitted from the phone to the nearest base station and incoming signals are sent from the base station to the phone at a slightly different frequency. When the signal reaches the nearest base station it can be transmitted to the main telephone network, either by telephone cables or by higher frequency radio links between an antenna at the base station and another at a terminal connected to the main telephone network.

10. Base Stations Each base station provides radio coverage to a geographical area known as a cell. Base stations are connected to one another by central switching centres, which track calls and transfer them as the caller moves from one cell to the next. An ideal network may be envisaged as consisting of a mesh of hexagonal cells, each with a base station at its centre. The cells overlap at the edges to ensure the mobile phone users always remain within range of the base station.

11. References Microphone IMAGE. Posted by Tom (2007). Houston’s Clear Thinkers. Weblog [Online] August 22. Available from: http://blog.kir.com/archives/2007/08/sports_talk_rad.asp [Accessed 22/01/11] National Astronauts and Space Administration. [Web Definition] [Accessed 22/01/11] Available form: http://science.hq.nasa.gov/kids/imagers/ems/radio.html National Astronauts and Space Administration(2010). [Online Image] [Accessed 22/01/11] Available form: http://science.hq.nasa.gov/kids/imagers/ems/radio.html OFCOM(2010) Mobile Cells [online images] Available form: http://www.sitefinder.ofcom.org.uk/mobilework.htm [Accessed 22/01/11]