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Unformatted text preview: tenuation reduces S/N with cable length,
which reduces capacity. But there is another factor that reduces
Higher frequencies generally attenuate more
than low frequencies, which reduces the usable
bandwidth. T wisted Pair - a pair of wires twisted together
to reduce electromagnetic coupling.
Common situation: four twisted pairs in a plastic
sheath. Often pre wired for 4 telephone connections.
Category 3 - fewer twists per centimeter
Category 5 - more twists per centimeter
Shielded twisted pair (STP) - metallic sheathing
around the pair
High rates - even 100 Megabits/second possible for
short distances, but high attenuation at high
frequencies greatly reduces capacity with length. Coaxial cable Insert Figure 2-4 Coaxial cable supplies much higher data
rates over long distance than twisted pair.
Signaling at frequencies up to 500 mhz is
feasible up to about a kilometer distance.
Long distance telephone
Short computer system links
Local area networks Optical Fiber
Show Figure 2-7 Glass core is 50 microns, or in single mode
fiber, 8-10 microns. Text says...
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This document was uploaded on 04/03/2014 for the course EE 362 at Pennsylvania State University, University Park.
- Fall '08