Chapter 3

Question 1

What is data communication?

Answer 1

Data communication is the transferring of information between computers.

Question 2

What are 3 basic requirements for successful communications?

Answer 2

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.

Question 3

What is a transmitter?

Answer 3

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.

Question 4

What is an antenna?

Answer 4

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.

Question 5

What is a receiver?

Answer 5

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.

Question 6

What is IR?

Answer 6

Intentional Radiator

A device that intentionally generates and emits radio frequency energy by radiation or induction.

Question 7

What is EIRP?

Answer 7

Equivalent Isotropically Radiated Power.

Is the highest RF signal strength that is transmitted from a particular antenna.

Question 8

What are the units of power (absolute)?

Answer 8

Watt
Miliwatt
dBm

Question 9

What are the units of comparison (relative)?

Answer 9

decibel
dBi
dBd

Question 10

What is a noise floor?

Answer 10

Is the ambient or background level of radio energy on a specific channel.

Bluetooth, portable telephones.

Question 11

What is SNR?

Answer 11

Signal to Noise Ratio

Signal quality is defined by it.

Question 12

What is a link budget?

Answer 12

Link budget is the sum of all gains and losses from the transmitting radio, through the RF medium, to the receiver radio.

Question 13

What is the purpose of link budget?

Answer 13

Its purpose is to guarantee that the final received signal amplitude is above the receiver sensitivity threshold of the receiver radio

Question 14

What RF component is responsible for generating the AC signal?

Answer 14

Transmitter

Question 15

A point source that radiates RF signal equally in all directions is known as what?

Answer 15

An isotropic radiator is known as point source.

Question 16

The sum of all the components from the transmitter to the antenna, not including the antenna, is known as what?

Answer 16

IR

Intentional Radiator

Question 17

WLAN vendors use RSSI thresholds to trigger which radio card behaviors?

Answer 17

Roaming

Dynamic Rate Switching

Question 18

dBi is a measure of what?

Answer 18

The signal increased caused by the antenna

Question 19

In a normal wireless bridged network, the greatest loss of signal is caused by what component?

Answer 19

FSPL

Question 20

How do you double the distance of my signal?

Answer 20

By increasing it by 6dB

Question 21

Which value should not be used to compare wireless network cards manufactured by different WLAN vendors?

Answer 21

RSSI