Chapter 3 77-82 Flashcards
transmit
to issue signals along a network medium such as cable
transmission
process of transmitting, or the progress of signals after they’ve been transmitted
volts
the measure of electrical signals
what determines the strength of a signal?
the voltage determines the strength of a signal
How can a signal travel?
through air as electromagnetic waves, through copper cable as electrical current, through fiber optic cable as light pulses
What is analog?
varying voltage, appears as a wavy lines
what are the 4 properties of a wave?
Amplitude, frequency, wavelength, phase
amplitude
measure of strength, height of wave at a measure of time
frequency
number of times the wave cycles from highest to lowest over a fixed period of time
how is frequency expressed?
cycles per second or Hz Hertz
wavelength?
the distance between two corresponding points in a waves cycle,
how is wavelength measured?
MHz meters
Phase
the pattern of the wave.
Out of phase means?
when two signals match, but one is at a different start point, so they don’t match
What is one benefit of an analog signal?
analog signals are more variable than digital, ie your voice and a computer voice
what is a drawback of analog?
the voltage varies and is imprecise
what is an analog signal susceptible to?
Noise – interference that degrades the signal
what is a digital signal?
pulses of precise positive voltages and zero voltages
what is the numeric representation of these pulses?
0 and 1
binary system?
0 and 1 to represent information
what is a bit?
a bit is a pulse in the digital signal
How many bits make a byte?
8
Why is digital transmission more reliable?
It only is pulses of patterns of 1 and 0, not variable waves
what is overhead?
the non data information that must accompany data, ie:layer, header, trailer that allow the network to route and interpret
