L5 - Optical fiber has very low attenuation. Show Fig. 2-7...

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Optical fiber has very low attenuation. Show Fig. 2-7 (2.6 in old text)
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UNGUIDED MEDIA Electromagnetic radiation - omnidirectional or directed Wireless advantages Communication from anywhere - Mobile communication Fixed devices - save on installing wires or optical fiber. Disadvantages Less private Interference with other wireless
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Free space propagation - Radiated signal spreads spherically (omnidirectional case) or approximately conically (directional case). The surface of a sphere (S = 4 ð R) 2 increases with the square of radius R. Excluding losses due to atmosphere or objects, the signal power received by a fixed size antenna falls inversely with R . 2 With losses and obstacles, received power may fall off with distance at a higher rate: R , e > 2. -e
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kilometer. If the distance is doubled, the power goes down by 1/4, or 6 dB. Thus the attenuation rule for free space is 6 dB per doubling of the distance. For a cable with attenuation of 20 dB, doubling the length increases attenuation to 40 dB. Quadrupling increases to 80 dB. For a free-space radio signal which is
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This note was uploaded on 07/16/2011 for the course EE 362 taught by Professor Unknow during the Spring '11 term at Penn College.

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L5 - Optical fiber has very low attenuation. Show Fig. 2-7...

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