Assignment 1: Wireless Data Transmission
Name: Fabio M. Cesar Professor: Patricia White Course: Enterprise Wireless Networks Date: 01/17/2013
A radio signal is an electromagnetic wave propagated by an antenna. Radio waves have different frequencies, and by tuning a receiver’s radio at a specific frequency, you can pick up a signal, because the starting point, or direction of the wave changes. An interesting aspect of radio waves is that each wireless technology has its “small band” available.
The most common frequency bands are:
• AM radio - 535 kilohertz to 1.7 megahertz
• shortwave radio - 5.9 MHz to 26.1 MHz
• CB radio - 26.96 megahertz to 27.41 megahertz
• TV channels - 54-88 MHz channel 2 through 6
• FM radio - 88 megahertz to 108 megahertz
• TV channels - 174 to 220 megahertz channel 7 until 13
• remote control garages, alarm systems, etc.: around 40 MHz
• cordless telephones: 40 to 50 MHz
• baby monitor: 49 MHz
• remote control airplanes: around 72 MHz
• remote control cars: around 75 MHz
• collars for tracking wild animals: 215 to 220 megahertz
• MIR space station: 145 megahertz and 437 megahertz
• cell phones: 824-849 MHz
• new cordless 900 MHz: around 900 megahertz.
• radar air traffic control: from 960 to 1.215 MHz
• Global Positioning System (GPS - Global Positioning System): 1.227 and 1.575 MHz
• radio communications in space: 2290 MHz to 2300 MH Amplitude modulation (AM) - the amplitude of the carrier from a transmitter is varied according to the signal against the signal of interest, which is the modulating signal. The frequency and carrier phase are kept constant. An AM signal is very prone to static and other electrical interference. Frequency modulation (FM) - changes the carrier frequency according to the information being conveyed. In FM, unlike the PM, the