Practice Exam Test Questions
Choose the letter of the best answer in each questions.
1. If the maximum amplitude of a sine wave is 2 V, the minimum amplitude is ________ V.
A) 2
B) 1
C) -2
D) between -2 and 2
Answer: Option C
2. _________ can impair a signal.
A) Noise
B) Attenuation
C) Distortion
D) All of the above
Answer: Option D
3. ________is the rate of change with respect to time.
A) Time
B) Frequency
C) Amplitude
D) Voltage
Answer: Option B
4. A signal is measured at two different points. The power is P1 at the first point and P2 at the second point. The dB is 0. This means ________.
A) P2 equals P1
B) P2 is zero
C) P2 is much larger than P1
D) P2 is much smaller than P1
Answer: Option A
5. Baseband transmission of a digital signal is possible only if we have a ____ channel.
A) bandpass
B) low-pass
C) high rate
D) low rate
Answer: Option B
6. ________ is a type of transmission impairment in which the signal loses strength due to the resistance of the transmission medium.
A) Distortion
B) Attenuation
C) Noise
D) Decibel
Answer: Option B
7. A sine wave in the ______ domain can be represented by one single spike in the _____ domain.
A) time; phase
B) frequency; time
C) time; frequency
D) phase; time
Answer: Option C
8. If the bandwidth of a signal is 5 KHz and the lowest frequency is 52 KHz, what is the highest frequency?
A) 5 KHz
B) 47 KHz
C) 57 KHz
D) 10 KHz
Answer: Option C
9. In a time-domain plot, the horizontal axis is a measure of ________.
A) phase
B) signal amplitude
C) frequency
D) time
Answer: Option D
10. _______ data are continuous and take continuous values.
A) digital
B) analog
C) (a) or (b)
D) none of the above
Answer: Option B
11. Frequency and period are ______.
A) proportional to each other
B) inverse of each other
C) the same
D) none of the above
Answer: Option B
12. When propagation speed is multiplied by propagation time, we get the ________.
A) wavelength of the signal
B) throughput
C) distance a signal or bit has traveled
D) distortion factor
Answer: Option C
13. A _________ sine wave is not useful in data communications; we need to send a _______ signal.
A) single-frequency; composite
B) composite; single-frequency This is the correct answer.
C) single-frequency; double-frequency
D) none of the above
Answer: Option A
14. The _________ product defines the number of bits that can fill the link.
A) delay-amplitude
B) frequency-amplitude
C) bandwidth-period
D) bandwidth-delay
Answer: Option D
15. _______ signals can have only a limited number of values.
A) Digital
B) Analog
C) (a) or (b)
D) None of the above
Answer: Option A
16. Before data can be transmitted, they must be transformed to ________.
A) periodic signals
B) electromagnetic signals
C) aperiodic signals
D) low-frequency sine waves
Answer: Option B
17. Data can be ________.
A) digital
B) analog
C) (a) or (b)
D) none of the above
Answer: Option C
18. ________ is a type of transmission impairment in which the signal loses strength due to the different propagation speeds of each frequency that makes up the signal.
A) Noise
B) Distortion
C) Attenuation
D) Decibel
Answer: Option B
19. Signals can be ________.
A) digital
B) analog
C) either (a) or (b)
D) neither (a) nor (b)
Answer: Option C
20. A sine wave is ________.
A) periodic and discrete
B) aperiodic and discrete
C) periodic and continuous
D) aperiodic and continuous
Answer: Option C
21. _______ data have discrete states and take discrete values.
A) Analog
B) Digital
C) (a) or (b)
D) None of the above
Answer: Option B
22. For a ______ channel, we need to use the Shannon capacity to find the maximum bit rate.
A) noiseless
B) noisy
C) low-pass
D) bandpass
Answer: Option B
23. What is the bandwidth of a signal that ranges from 1 MHz to 4 MHz?
A) 1 KHz
B) 3 MHz
C) 4 MHz
D) none of the above
Answer: Option B
24. _____ signals can have an infinite number of values in a range.
A) Analog
B) Digital
C) (a) or (b)
D) None of the above
Answer: Option A
25. A(n)_________ signal is a composite analog signal with an infinite bandwidth.
A) digital
B) analog
C) either (a) or (b)
D) neither (a) nor (b)
Answer: Option A
26. A periodic signal completes one cycle in 0.001 s. What is the frequency?
A) 1 Hz
B) 100 Hz
C) 1 KHz
D) 1 MHz
Answer: Option C
27. The _____ of a composite signal is the difference between the highest and the lowest frequencies contained in that signal.
A) period
B) bandwidth
C) frequency
D) amplitude
Answer: Option B
28. ________ is a type of transmission impairment in which an outside source such as crosstalk corrupts a signal.
A) Noise
B) Distortion
C) Attenuation
D) Decibel
Answer: Option A
29. _______ describes the position of the waveform relative to time 0.
A) Amplitude
B) Phase
C) Frequency
D) Voltage
Answer: Option B
30. Given two sine waves A and B, if the frequency of A is twice that of B, then the period of B is ________ that of A.
A) one-half
B) twice
C) the same as
D) indeterminate from
Answer: Option B
31. As frequency increases, the period ________.
A) increases
B) decreases
C) doubles
D) remains the same
Answer: Option B
32. If the available channel is a ______ channel, we cannot send a digital signal directly to the channel.
A) low-pass
B) low rate
C) bandpass
D) high rate
Answer: Option C
33. For a ______ channel, the Nyquist bit rate formula defines the theoretical maximum bit rate.
A) low-pass
B) bandpass
C) noisy
D) noiseless
Answer: Option D
34. In a frequency-domain plot, the horizontal axis measures the ________.
A) phase
B) frequency
C) slope
D) peak amplitude
Answer: Option B