Chapter 3 Flashcards
What is data communication?
Data communication is the transferring of information between computers.
What are 3 basic requirements for successful communications?
Two or more devices want to communicate.
There must be a medium, a means, or a method for them to use to communicate.
There must be a set of rules for them to use when they communicate.
What is a transmitter?
Transmitter is the initial component in the creation of the wireless medium.
Transmitter takes the data provided and modifies the AC signal by using a modulation technique to encode the data into the signal.
What is an antenna?
An antenna provides two functions in a communication system.
Antenna takes the RF waves that it receives through the air and directs the AC signal to the receiver.
What is a receiver?
Receiver is the final component in the wireless medium. The Receiver takes the carrier signal that is received from the antenna and translates the modulated signals into binary.
What is IR?
Intentional Radiator
A device that intentionally generates and emits radio frequency energy by radiation or induction.
What is EIRP?
Equivalent Isotropically Radiated Power.
Is the highest RF signal strength that is transmitted from a particular antenna.
What are the units of power (absolute)?
Watt
Miliwatt
dBm
What are the units of comparison (relative)?
decibel
dBi
dBd
What is a noise floor?
Is the ambient or background level of radio energy on a specific channel.
Bluetooth, portable telephones.
What is SNR?
Signal to Noise Ratio
Signal quality is defined by it.
What is a link budget?
Link budget is the sum of all gains and losses from the transmitting radio, through the RF medium, to the receiver radio.
What is the purpose of link budget?
Its purpose is to guarantee that the final received signal amplitude is above the receiver sensitivity threshold of the receiver radio
What RF component is responsible for generating the AC signal?
Transmitter
A point source that radiates RF signal equally in all directions is known as what?
An isotropic radiator is known as point source.
The sum of all the components from the transmitter to the antenna, not including the antenna, is known as what?
IR
Intentional Radiator
WLAN vendors use RSSI thresholds to trigger which radio card behaviors?
Roaming
Dynamic Rate Switching
dBi is a measure of what?
The signal increased caused by the antenna
In a normal wireless bridged network, the greatest loss of signal is caused by what component?
FSPL
How do you double the distance of my signal?
By increasing it by 6dB
Which value should not be used to compare wireless network cards manufactured by different WLAN vendors?
RSSI
