radio communication and the mobile phone
TRANSCRIPT
RADIO COMMUNICATION AND THE MOBILE PHONE
A Wonderful Presentation by Gareth Dakin
RADIO COMMUNICATION
•A little over a hundred years since Marconi’s first
transmission , 60% of the UK enjoy the benefits of
mobile phone use.
RADIO WAVES
•Mobile phones transmit and receive signals using
electromagnetic waves or radio waves
•Electromagnetic radiation consists of oscillating
electric, magnetic fields and the frequency
FREQUENCY
•Frequency is the number of times per second at
which the wave oscillates
•This is measured in Hertz (Hz)
•Between 30 kHz and 300 GHz is what’s used for
telecommunications including radio
FREQUENCY
•The UK AM radio uses frequencies between 180
kHz and
1.6 MHz
• Mobile frequency range is between 872-960 MHz,
1710-1872 MHz and 1920-2170 MHz
RADIO COMMUNICATION USING AMPLITUDE
MODULATION
•Radio frequency wave used for radio communication
is known as a carrier wave
•The carrier wave is produced by the transmitter as
a sine wave
•For the radio wave to convey information such as
speech information needs to be added to the carrier
wave, this is modulation
RADIO COMMUNICATION USING AMPLITUDE
MODULATION
•For amplitude modulation electrical signals from a
microphone is used to vary the amplitude of the
carrier wave
•At any instant the amplitude of the carrier wave is
made proportional to the size of the electrical
modulating signal
•There are many types of modulating techniques
with different characteristics for different
applications
MOBILE PHONE NETWORKS USING RADIO
COMMUNICATION
•A mobile phone sends and receives information via radio
communication
•Radio frequency signals are transmitted from the phone to
the nearest base station
•Incoming signals are sent from the base station to the
phone at a slightly different frequency
•Base stations link mobile phones to the rest of the network
MOBILE PHONE NETWORKS USING RADIO
COMMUNICATION
•Signals are transmitted to the network via
telephone cables or higher frequency radio links
between an antenna
•Each base station provides radio coverage to a
geographical area known as a cell
BIBLIOGRAPHY
Geo Tau Aisay (2009) Radio waves [Online image]. Available from:
http://www.ieeeghn.org/wiki/index.php/Radio_Waves [24/01/11]
Hardware sphere (2010) Nokia to charge phone via radio waves [Online image]. Available from:
http://www.hardwaresphere.com/2009/06/12/nokia-to-charges-phone-via-radio-waves-in-201x/
[24/01/11]
Lee global history network (2011) Radio waves modulated by amplitude and frequency [Online
image]. Available from: http://www.ieeeghn.org/wiki/index.php/Radio_Waves [25/01/11]
Public telecommunication networks unit (2001) How mobile phone networks work [WWW] Ofcom.
Available from: http://www.sitefinder.ofcom.org.uk/mobilework.htm [18/01/11]
Queensland university (2010) Mobile phones [Online image]. Available from: http://
www.fmd.qut.edu.au/campus_services/cleaning/waste_disposal/mobile_phone.jsp [24/01/11]
Virtual systems e-blacktech (unknown) Structure of cellular network [Online image]. Available
from: http://www.e-blacktech.com/telephoneservice/cellphones.html [25/01/11]