Wireless signals are electromagnetic waves, which can travel through space. No physical medium is necessary for wireless signals, which travel as well in the vacuum of space as they do through the air in an office building. The ability of radio waves to pass through walls and cover great distances makes wireless a versatile way to build a network. Figure shows wireless technologies and features.
The waves differ only in their frequency. Power waves, radio waves, microwaves, Infrared light waves, visible light waves, ultraviolet light waves, x-rays, and gamma rays share some very important characteristics:
-All of these waves have an energy pattern.
-All of these waves travel at the speed of light, c = 299,792,458 meters per second, in a vacuum. This speed might more accurately be called the speed of electromagnetic waves.
-All of these waves obey the equation (frequency) x (wavelength) = c.
-All of these waves will travel through a vacuum. However, they have very different interactions with various materials.
-The primary difference among different electromagnetic waves is their frequency. Low frequency electromagnetic waves have a long wavelength, while high frequency electromagnetic waves have a short wavelength. Wavelength represents the distance from one peak to the next on the sine wave.
The interactive calculator can be used for the following activities:
-Enter a frequency and notice that the calculator displays the wavelength.
-Enter a wavelength and notice that the calculator displays the frequency.
-In either case, the calculator displays the electromagnetic wave associated with the calculation.
-Enter a frequency and notice that the calculator displays the wavelength.
-Enter a wavelength and notice that the calculator displays the frequency.
-In either case, the calculator displays the electromagnetic wave associated with the calculation.
Wireless ApplicationsA common application of wireless data communication is for mobile use. Some examples of mobile use include the following:
-Person-to-person communications from moving cars or airplanes
-Satellite communication relays
-Telemetry signals to remote space probes
-Communication links to space shuttles and space stations
-Communications without reliance on copper or optical fiber tethers
-Any-to-any communications to exchange network data
-Person-to-person communications from moving cars or airplanes
-Satellite communication relays
-Telemetry signals to remote space probes
-Communication links to space shuttles and space stations
-Communications without reliance on copper or optical fiber tethers
-Any-to-any communications to exchange network data