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- CWNA-107
21.
When the multiple RF signals arrive at a receiver at the same time and are ________ with the
primary wave, the result can be ________ of the primary signal.
- A.out of phase, scattering
- B.in phase, intersymbol interference
- C.in phase, attenuation
- D.180 degrees out of phase, amplification
- E.in phase, cancellation
- F.180 degrees out of phase, cancellation
- Answer & Explanation
- Report
Answer : [F]
Explanation :
Explanation :
| Nulling, or cancellation, can occur when multiple RF signals arrive at the receiver at the same time and are 180 degrees out of phase with the primary wave. |
22.
Which of the following statements are true? (Choose all that apply.)
- A.When upfade occurs, the final received signal will be stronger than the original transmitted signal.
- B.When downfade occurs, the final received signal will never be stronger than the original transmitted signal.
- C.When upfade occurs, the final received signal will never be stronger than the original transmitted signal.
- D.When downfade occurs, the final received signal will be stronger than the original transmitted signal.
- Answer & Explanation
- Report
Answer : [B, C]
Explanation :
Explanation :
| When the multiple RF signals arrive at the receiver at the same time and are in phase or partially out of phase with the primary wave, the result is an increase in signal strength (amplitude). However, the final received signal, whether affected by upfade or downfade, will never be stronger than the original transmitted signal because of free space path loss. |
23.
What is the frequency of an RF signal that cycles 2.4 million times per second?
- A.2.4 hertz
- B.2.4 MHz
- C.2.4 GHz
- D.2.4 kilohertz
- E.2.4 KHz
- Answer & Explanation
- Report
Answer : [B]
Explanation :
Explanation :
| 802.11 wireless LANs operate in the 5 GHz and 2.4 GHz frequency range. However, 2.4 GHz is equal to 2.4 billion cycles per second. The frequency of 2.4 million cycles per second is 2.4 MHz. |
24.
What is the best example of a time domain tool that could be used by an RF engineer?
- A.Oscilloscope
- B.Spectroscope
- C.Spectrum analyzer
- D.Refractivity gastroscope
- Answer & Explanation
- Report
Answer : [A]
Explanation :
Explanation :
| An oscilloscope is a time domain tool that can be used to measure how a signal’s amplitude changes over time. A frequency domain tool called a spectrum analyzer is a more commonplace tool most often used during site surveys. |
25.
What are some objects or materials that are common causes of reflection? (Choose all that
apply.)
- A.Metal
- B.Trees
- C.Asphalt road
- D.Lake
- E.Carpet floors
- Answer & Explanation
- Report
Answer : [A, C, D]
Explanation :
Explanation :
| This is a tough question to answer because many of the same mediums can cause several different propagation behaviors. Metal will always bring about reflection. Water is a major source of absorption; however, large bodies of water can also cause reflection. Flat surfaces such as asphalt roads, ceilings, and walls will also result in reflection behavior. |
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