18-01-2012, 04:33 PM
William StallingsData and Computer Communications7th Edition
03-DataTransmission.ppt (Size: 392 KB / Downloads: 21)
Frequency Domain Concepts
Signal usually made up of many frequencies
Components are sine waves
Can be shown (Fourier analysis) that any signal is made up of component sine waves
Can plot frequency domain functions
Spectrum & Bandwidth
.Spectrum
range of frequencies contained in signal
.Absolute bandwidth
width of spectrum
.Effective bandwidth
Often just bandwidth
Narrow band of frequencies containing most of the energy
.DC Component
Component of zero frequency
Data Rate and Bandwidth
.Any transmission system has a limited band of frequencies
.This limits the data rate that can be carried
Analog and Digital Data
.Analog
-Continuous values within some interval
-e.g. sound, video
.Digital
-Discrete values
- e.g. text, integers