Deck 1: Fundamental Communications Concept

Question 1

Which of the following is the most troublesome form of external noise?

A)Atmospheric
B)Human-made
C)Space
D)Thermal

Answer 1

B

Question 2

Electronics as a discipline within the field of physical science emerged from the discovery of __________.

A)microwaves
B)gamma rays
C)cosmic rays
D)radio waves

Answer 2

D

Question 3

Which of the following did French mathematician Jean Baptiste Joseph Fourier develop?

A)A means to break down any periodic waveform into a series of sine and/or cosine waves at multiples of the fundamental frequency.
B)He created thermal interactions between free electrons and vibrating ions in a conductor.
C)The formula for calculating shot noise contributed for a complete transistor.
D)The relative measure of the desired signal power to the noise power.

Answer 3

A

Question 4

Electric and magnetic fields both result from voltage potentials and _________.

A)Radio frequencies
B)Audio frequencies
C)Current flows
D)Electric charges

Question 5

What three ratios do decibels represent?

A)Powers, voltages, currents
B)Powers, voltages, frequencies
C)Voltages, frequencies, impedances
D)Logarithms, voltages, currents

Question 6

What do modulated signals convey?

A)Information
B)Voltage
C)Noise
D)Power

Question 7

What agency in the United States has been given the authority to establish and enforce regulations regarding the use of radio transmitters and other generators of radio-frequency energy?

A)Transport and Communications Ministry
B)Federal Communications Commission (FCC)
C)International Telecommunication Union (ITU)
D)Bell Laboratories

Question 8

If you were troubleshooting a piece of equipment and you heard a frying noise,what would this indicate?

A)A wire is loose
B)The power is weakening
C)A component is about to fail
D)The equipment has been abused

Question 9

Why would you use Friiss's formula?

A)To provide the overall noise effect of a multistage system.
B)To break down any periodic waveform into a series of sine and/or cosine waves at multiples of the fundamental frequency.
C)To establish that different users can share bands of frequencies provided that each user was assigned exclusive use of a frequency range within that band.
D)To show how the construction of a square wave can be seen to be made up of a number of sinusoids.

Question 10

When troubleshooting,why would you perform voltage and resistance checks?

A)To check for signals
B)To eliminate induced failures
C)To observe frequency spectra
D)To isolate defective components

Question 11

What does the graphical display produced by an oscilloscope represent?

A)Signals in the frequency domain
B)Time-domain representation
C)Amplitude of each frequency component
D)Amplitude characteristics

Question 12

____________ consists of a mixture of signals at all frequencies and at randomly occurring amplitudes.

A)Decibel units
B)Frequency
C)Bandwidth
D)Noise

Question 13

You are troubleshooting a piece of equipment and you find that unauthorized modifications may have been performed on the equipment.What type of failure does this situation represent?

A)Faulty
B)Complete
C)Induced
D)Poor system performance

Question 14

The overall noise-intensity versus frequency curves for semiconductor devices would have what type of shape?

A)Angular
B)Square
C)Bathtub
D)Uneven

Question 15

Which of the following is an essential attribute for being an effective troubleshooter?

A)To know the latest trends in noise analysis
B)To be able to limit the frequency response
C)To know the conversion from the time to the frequency domain
D)To be able to isolate faulty components quickly and repair the defective circuit

Question 16

White noise is directly proportional to both temperature and _____________.

A)bandwidth
B)AC voltage
C)power transfer
D)frequency

Question 17

Which of the following could cause a complete failure in a piece of equipment?

A)Sporadic circuit operation
B)Open power resistors
C)Poor soldering
D)Poor alignment

Question 18

Which of the following pieces of equipment would be considered advanced test equipment?

A)Digital multimeter (DMM)
B)Broadband oscilloscope
C)Spectrum analyzer
D)RF generator

Question 19

What two factors limit all communication systems?

A)Bandwidth and noise
B)Bandwidth and frequency
C)Noise and decibels
D)Noise and currents

Question 20

The carrier is often a(n)_____________.

A)sine wave
B)vector
C)angular frequency
D)amplitude modulation

Question 21

What does the noise figure (NF)specify?
A)Exactly how noisy a device is

A)The ultimate noise performance
B)The noise content at a specific point
C)The paths in which the charge carriers move

Question 22

The terms Johnson,thermal,and _____ noise may be used interchangeably.

A)white
B)space
C)internal
D)external

Question 23

Which of the following defines frequency domain?

A)Square waves are made up of the fundamental and its odd -numbered harmonics
B)Amplitude is viewed as a function of frequency rather than of time
C)Amplitude of each harmonic decreases as the frequency increases
D)Any or all of the sine or cosine terms may be zero, and there are no restrictions on their amplitudes

Question 24

What is the function of a transducer?

A)Displays waveforms in the time domain
B)Converts energy from one form to another
C)Allows for spectrum analysis to be accomplished relatively easily in software
D)Supplies test signal at the input of a circuit

Question 25

Why are bandwidths valuable?

A)Waveforms are limited.
B)Analog signals are digitized.
C)Wireless channels are impractical.
D)Frequencies are scarce.