On another frequency signal typically requires geo

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Unformatted text preview: nce telephone private business networks global positioning Satellite Point to Point Link Satellite Satellite Broadcast Link Satellite Broadcast Radio Broadcast radio is 3kHz to 300GHz use broadcast radio, 30MHz - 1GHz, for: FM radio UHF and VHF television is omni directional still need line of sight suffers from multipath interference reflections from land, water, other objects Infrared Infrared modulate non-coherent infrared light end line of sight (or reflection) are blocked by walls no licenses required typical uses TV remote control IRD port Wireless Propagation Wireless Ground Wave Wireless Propagation Wireless Sky Wave Wireless Propagation Wireless Line of Sight Refraction Refraction velocity of electromagnetic wave is a function of velocity density of material density ~3 x 108 m/s in vacuum, less in anything else speed changes as move between media Index of refraction (refractive index) is sin(incidence)/sin(refraction) varies with wavelength have gradual bending if medium density varies density of atmosphere decreases with height results in bending towards earth of radio waves hence optical and radio horizons differ Line of Sight Transmission Line Free space loss loss of signal with distance Atmospheric Absorption from water vapour and oxygen absorption Multipath multiple interfering signals from reflections Refraction bending signal away from receiver Multipath Interference Multipath Summary Summary looked at data transmission issues frequency, spectrum & bandwidth analog vs. digital signals transmission impairments...
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This note was uploaded on 12/27/2012 for the course TELECOM 302 taught by Professor Usman during the Spring '12 term at University of Engineering & Technology.

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