True/False
Indicate whether the sentence or statement is true
or false.
|
|
|
1.
|
In a
wireless transmission data travels on invisible radio waves.
|
|
|
2.
|
Whenever a wave completes its trip and returns back to the starting point it has
finished two cycles.
|
|
|
3.
|
The
ASK 1 bit has a carrier signal (positive voltage) while a 0 bit has no signal (zero
voltage).
|
|
|
4.
|
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
|
|
|
5.
|
Highly-directional antennas are generally concave dish-shaped devices.
|
Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
|
|
|
6.
|
Electromagnetic waves travel freely through space in all directions at the speed of
light, or approximately ____ per second. a. | 1 kilometer | c. | 186,000 miles | b. | 100
kilometers | d. | 93,000,000
miles | | | | |
|
|
|
7.
|
Which
of the following is an electromagnetic wave? a. | light | c. | radio | b. | heat | d. | All of the
above | | | | |
|
|
|
8.
|
Which
of the following types of wave is imperceptible? a. | light | c. | heat | b. | radio | d. | ether | | | | |
|
|
|
9.
|
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 | c. | amplifier | b. | translator | d. | phaser | | | | |
|
|
|
10.
|
Which
of the following units is used to measure frequency? a. | decibel | c. | hertz | b. | volt | d. | byte | | | | |
|
|
|
11.
|
The
term ____ describes the rate of electrical flow. a. | voltage | c. | resistance | b. | current | d. | electrical
power | | | | |
|
|
|
12.
|
____
modulation changes the number of waves representing one cycle. a. | Amplitude | c. | Frequency | b. | Phase shift | d. | Phase | | | | |
|
|
|
13.
|
Television uses three types of modulation. The video portion uses
____.
|
|
|
14.
|
Which
digital modulation technique is similar to frequency modulation? a. | amplitude shift
keying | c. | phase shift
keying | b. | frequency shift keying | d. | All of the above | | | | |
|
|
|
15.
|
____
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 | c. | Loss | b. | Modulation | d. | Gain | | | | |
|
|
|
16.
|
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 | c. | refraction | b. | absorption | d. | scattering | | | | |
|
|
|
17.
|
Which
type of RF loss is caused by the equipment transmitting the signal? a. | Scattering | c. | Diffraction | b. | Voltage Standing Wave Ratio | d. | Absorption | | | | |
|
|
|
18.
|
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 | | |
|
|
|
19.
|
A
loss of 10 decibels means that ____ percent of the power has been lost in mW.
|
|
|
20.
|
The
maximum EIRP for IEEE 802.11b WLANs is ____ mW.
|
|
|
21.
|
The
length of an antenna should be about ____ the wavelength. a. | 1/10
of | c. | 1/2
of | b. | 1/4 of
| d. | equal
to | | | | |
|
|
|
22.
|
____
polarization is typically used in wireless LANs with the dual antennas of access points pointing
upward. a. | Vertical | c. | Circular | b. | Horizontal | d. | Dual | | | | |
|
|
|
23.
|
What
is the shape of a Fresnel zone? a. | Circular | c. | Ellipsoidal | b. | Rectangular | d. | Elliptical | | | | |
|
|
|
24.
|
What
is the free space loss (in dB) for IEEE 802.11b and 802.11g WLANs when the distance in meters is
100?
|
|
|
25.
|
A
____ dipole antenna produces a flatter signal than a standard dipole antenna. a. | Fresnel | c. | zoned | b. | high-gain | d. | semi-directional | | | | |
|
|
|
26.
|
____
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 | c. | Semi-directional | b. | Omni-directional | d. | Highly-directional | | | | |
|
Completion
Complete each sentence or
statement.
|
|
|
27.
|
A(n)
____________________ signal has numerous starts and stops throughout the signal stream.
|
|
|
28.
|
Resistance is measured in ohms and the total amount of resistance is called the
____________________.
|
|
|
29.
|
____________________ is defined as the positive difference in amplitude between
two signals.
|
|
|
30.
|
RF
power gain and loss on a relative scale are measured in ____________________ instead of
mW.
|
|
|
31.
|
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.
|
Matching
|
|
|
Match each term with the correct statement below. a. | diffraction | f. | voltage | b. | loss | g. | scattering | c. | electrical
power | h. | polarization | d. | oscillating signal | i. | frequency | e. | modulation | | | | |
|
|
|
32.
|
voltage multiplied by the current
|
|
|
33.
|
up-and-down wave
|
|
|
34.
|
orientation of the radio waves as they leave the antenna
|
|
|
35.
|
rate
at which an event occurs
|
|
|
36.
|
bending caused by an object in the path of the transmission
|
|
|
37.
|
changes to a signal that can be made to enable it to carry information
|
|
|
38.
|
equal
to current times resistance
|
|
|
39.
|
negative difference in amplitude between signals
|
|
|
40.
|
occurs when the RF signal comes in contact with elements in the air, such as rain or
heavy dust particles
|
Short Answer
|
|
|
41.
|
Why
is it important to understand how wireless technology works?
|
|
|
42.
|
What
is the difference between an analog and digital signal? Provide an example of each signal
type.
|
|
|
43.
|
What
is amplitude modulation?
|
|
|
44.
|
There
are several advantages of digital modulation over analog modulation. What are
they?
|
|
|
45.
|
There
are several factors that may result in RF loss. List and describe three of them.
|
|
|
46.
|
How
is RF power measured?
|
|
|
47.
|
How
does an antenna work?
|
|
|
48.
|
What
is polarization?
|
|
|
49.
|
What
is antenna diversity?
|
|
|
50.
|
What
is the most common type of antenna for a WLAN?
|