Deck 3: How Wireless Works

Question 1

What is a problem with measuring RF loss using a linear scale?

A) it does not reveal what the loss is in relation to the whole
B) it is inaccurate
C) it is difficult to calculate
D) it requires complex measurements

Answer 1

A

Question 2

Electromagnetic waves travel freely through space in all directions at the speed of light, or approximately ____ per second.

A) 1 kilometer
B) 100 kilometers
C) 186,000 miles
D) 93,000,000 miles

Answer 2

C

Question 3

____ can occur intentionally from an external power source that amplifies the signal, or unintentionally when an RF signal bounces off an object and combines with the original signal to amplify it.

A) Phase shift
B) Modulation
C) Loss
D) Gain

Answer 3

D

Question 4

When an RF signal moves from one medium to another of a different density the signal actually bends instead of traveling in a straight line. This is known as ____.

A) reflection
B) absorption
C) refraction
D) scattering

Question 5

When a digital signal needs to be transmitted over an analog medium, such as when a computer needs to send digital signals over an analog telephone line or TV cable, a device known as a(n) ____ is used.

A) modem
B) translator
C) amplifier
D) phaser

Question 6

Which of the following units is used to measure frequency?

A) decibel
B) volt
C) hertz
D) byte

Question 7

A basic rule of thumb is that each 6 dB increase in EIRP results in a quadrupling of the transmission range (distance from the antenna), and a 6 dB reduction in EIRP translates into reducing the range by four

Question 8

Which type of RF loss is caused by the equipment transmitting the signal?

A) Scattering
B) Voltage Standing Wave Ratio
C) Diffraction
D) Absorption

Question 9

Television uses three types of modulation. The video portion uses ____.

A) AM
B) FM
C) DM
D) PM

Question 10

The ASK 1 bit has a carrier signal (positive voltage) while a 0 bit has no signal (zero voltage).

Question 11

Whenever a wave completes its trip and returns back to the starting point it has finished two cycles.

Question 12

____ modulation changes the number of waves representing one cycle.

A) Amplitude
B) Phase shift
C) Frequency
D) Phase

Question 13

The term ____ describes the rate of electrical flow.

A) voltage
B) current
C) resistance
D) electrical power

Question 14

Which of the following is an electromagnetic wave?

A) light
B) heat
C) radio
D) All of the above

Question 15

Which digital modulation technique is similar to frequency modulation?

A) amplitude shift keying
B) frequency shift keying
C) phase shift keying
D) All of the above

Question 16

In a wireless transmission data travels on invisible radio waves.

Question 17

The maximum EIRP for IEEE 802.11b WLANs is ____ mW.

A) 10
B) 100
C) 1000
D) 10,000

Question 18

A loss of 10 decibels means that ____ percent of the power has been lost in mW.

A) 10
B) 30
C) 90
D) 100

Question 19

Which of the following types of wave is imperceptible?

A) light
B) radio
C) heat
D) ether

Question 20

Highly-directional antennas are generally concave dish-shaped devices.

Question 21

A(n) ____________________ signal has numerous starts and stops throughout the signal stream.

Question 22

What is amplitude modulation?

Question 23

____ antennas are used for long distance, point-to-point wireless links, such as connecting buildings that are up to 42 kilometers (25 miles) apart.

A) Fresnel
B) Omni-directional
C) Semi-directional
D) Highly-directional

Question 24

What is the free space loss (in dB) for IEEE 802.11b and 802.11g WLANs when the distance in meters is 100?

A) 80
B) 88
C) 92
D) 97

Question 25

____ polarization is typically used in wireless LANs with the dual antennas of access points pointing upward.

A) Vertical
B) Horizontal
C) Circular
D) Dual

Question 26

What is the shape of a Fresnel zone?

A) Circular
B) Rectangular
C) Ellipsoidal
D) Elliptical

Question 27

How does an antenna work?

Question 28

A ____ dipole antenna produces a flatter signal than a standard dipole antenna.

A) Fresnel
B) high-gain
C) zoned
D) semi-directional

Question 29

Why is it important to understand how wireless technology works?

Question 30

Resistance is measured in ohms and the total amount of resistance is called the ____________________.

Question 31

There are several factors that may result in RF loss. List and describe three of them.

Question 32

What is the difference between an analog and digital signal? Provide an example of each signal type.

Question 33

____________________ is defined as the positive difference in amplitude between two signals.

Question 34

How is RF power measured?

Question 35

What is polarization?

Question 36

RF power gain and loss on a relative scale are measured in ____________________ instead of mW.

Question 37

There are several advantages of digital modulation over analog modulation. What are they?

Question 38

The length of an antenna should be about ____ the wavelength.

A) 1/10 of
B) 1/4 of
C) 1/2 of
D) equal to

Question 39

A(n) ____________________ is a copper wire or similar device that has one end up in the air and the other end connected to the ground or a grounded device.

Question 40

What is antenna diversity?

Question 41

What is the most common type of antenna for a WLAN?