The use and importance of radio waves and


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The use and importance of radio waves and

  2. 2. Radio waves and signals are used in a number of different devices, and are in no way confined to radio broadcasting.Other uses of radio waves and signals include · Cordless phones · Garage door openers · Wireless networks · Radio-controlled toys · Television broadcasts · Mobile phones · GPS receivers · MRI · Satellite communications · Police radios · Wireless clocks
  3. 3. SOME EXAMPLES IN MORE DETAILCordless PhonesA cordless telephone is a combination of a telephone and a radio transmitter/receiver. There are two main parts- the base and the handset. The base and phone are attached by a standard phone wire connection. The base receives incoming calls through the phone line (as an electrical signal) and converts it to an FM radio signal before broadcasting the signal. The telephone reaches the radio signal, converts it back into an electrical signal to the speaker where is it then converted into sound. When the person talks the system basically goes the opposite way. The handset broadcasts your voice back through a separate FM signal back to the base which then converts it to an electrical signal once again and through the phone line to the other party. This is called a duplex frequency.
  4. 4. Wireless NetworksA computers wireless adapter translates data into a radio signal and transmits it using an antenna. Then a wireless router receives the signal and decodes it. The router sends the information to the Internet using a physical, wired connection (Ethernet)This process also works in reverse(much like the cordless phone) , with the router receiving information from the Internet, translating it into a radio signal and sending it to the computers wireless adapter.Wi-Fi has a lot of advantages. Wireless networks are easy to set up and don’t cost much. They transmit at frequencies of 2.4 GHz or 5 GHz. This frequency is much higher than the frequencies used for cell phones and walkie-talkies. The frequency being higher allows the signal to carry more data.
  5. 5. TelevisionDifferent channels on a television use different frequencies ( carrier waves) and television receivers are designed so that they can tune into a certain frequency at a certain time and ignore other signals.The radio signals received by a TV antenna are normally weak and so have to be amplified, before being demodulated through a tuner. The tuner produces electromagnetic waves of the same frequencies as the carrier waves ( used to broadcast channels)Signals are sent to the antenna, which then sends the signal out into the air as electromagnetic waves. The receiver receives the waves and demodulates the signal before recreating the original sounds/ images.
  6. 6. MRI (Magnetic resonance imaging)Radio frequency (RF) energy has been used in medical treatments for over 75 yearsRadio waves are used in MRI scans to give 3D images of the body. The magnet in the scanner causes all the protons in the body to align, a radio wave pulse causes the protons to move out of alignment in different directions, generating the 3D image and giving a doctor the ability to look at tissue, bone and fluid inside a patient. Once the Radio wave pulse is turned off the protons realign.
  7. 7. Radio controlled toys ( e.g. Cars)The transmitter sends a signal over a frequency to the receiver in the toy. The transmitter usually has a 9-volt battery, that provides the power for the controls and the transmission of the signal.The main difference between radio controlled and remote controlled toys is that whilst the remote controlled toys have a wire that connects the controller and toy, radio controlled toy s are always wireless. Most RC toys operate at either 27 MHz or 49 MHzThis pair of frequencies has been chosen for both these toys and other basic consumer items, such as garage door openers and walkie- talkies.The way that the signal reaches the controls the car is similar to the radios created in our lab sessions, inside the toy there is a circuit which includes all the necessary equipment to pick up the radio signal. “capacitors, resistors and diodes, as well as the IC that controls the motors. The radio receiver consists of a crystal that oscillates at a specific frequency, inductors and an antenna.”
  8. 8. Clearly radio waves are a large feature in a modern society, branching much further that just as a form of entertainment. Radio waves and signals control various pieces of important technology that helps us stay connected ( e.g. mobile phones, cordless phones and Wi-Fi) but also keep us safe and healthy ( MRI scans and police radio)Eventually, I expect that an even larger proportion of technology will become “wireless” and therefore controlled by radio waves, and whilst this is positive in terms of effectiveness and ease. There is also the issue of loosing one’s privacy and the issues that would follow if the “system” that we are already so reliable on were to have a problem
  9. 9. BBC - Learning Zone Class Clips - Radio waves and MRI scans - the electromagnetic spectrum - Science Video. 2012. BBC - Learning Zone Class Clips - Radio waves and MRI scans - the electromagnetic spectrum - Science Video. [ONLINE] Available at: waves-and-mri-scans-the-electromagnetic-spectrum/1457.html. [Accessed 26 January 2012].HowStuffWorks "How Cordless Telephones Work". 2012. HowStuffWorks "How Cordless Telephones Work". [ONLINE] Available at: [Accessed 26 January 2012].HowStuffWorks "Inside an RC Truck". 2012. HowStuffWorks "Inside an RC Truck". [ONLINE] Available at: toy3.htm. [Accessed 27 January 2012].HowStuffWorks "What Is WiFi?". 2012. HowStuffWorks "What Is WiFi?". [ONLINE] Available at: network1.htm. [Accessed 27 January 2012].Radio and Television. 2012. Radio and Television. [ONLINE] Available at: [Accessed 26 January 2012].