Computer Systems Technology DCN386 Lecture Notes - Lecture 6: Fast Ethernet, Non-Return-To-Zero, Bit Rate
14 Dec 2015
School
Department
Professor
Document Summary
Signaling change of the medium data being sent. Encoding interpreting the signal that is being sent (to establish rules). Bit time individual time in the signal, to separate bits. Used to tell when and when not to read. Signal can be interpreted with noise ( with the help of a repeater-for digital signal-rebuilds signal)/ less packet loss. Emi can create false positives ( depends on encoding method) Manchester (self-clocking): synchronizes clocks by looking at the change of the voltage, uses dead zones to prevent emi interference. Rejects voltages from a certain range: disadvantage: twice the amount of time. Less efficient: reliability (clocking) over efficiency ( twice the time for bit times) Every change in voltage is a change in bit. The longer the same voltages/bits the farther the synchronization drifts apart. Advantage: efficient - less change in voltage. Amplifier boosts power to the signal, though it is not perfect. Quadrature amplitude modulation (qam) to send more data more per wave.
