20-07-2012, 02:52 PM
Transmission Media
Transmission Media.ppt (Size: 2.88 MB / Downloads: 59)
Guided Media determine the path of the signal
Wires (cables, twisted pair, coax)
Fiber Optics
Other things…
Signals Propagate in all directions in Unguided Media
The medium is usually free space (air), but the signal type gets the name
Refers to transmitting signals through passive media that does not change the signal’s direction
Microwaves, broadcast radio waves
Lasers, Infrared
How Fast/How Far can a Signal be Sent?
The question:
Given a source signal with a given power, how far can it go before it is attenuated so much that the SNR is too low to be usable?
Attenuation increases with distance. Usually expressed in dB/m, dB/100ft, etc.
Guided Media
Guided media control the path of the signal wave
Electrical – Signal needs conductor and ground
Differences are in how ground/conductor interact
Twisted pair
Coax
Striplines on PCBs