In this section of Data Communication and Networking – Data and Signals MCQ (Multiple Choice) Based Questions and Answers,it cover the below lists of topic, All the Multiple Choice Question and Answer (MCQs) have been compiled from the books of Data Communication and Networking by The well known author behrouz A forouzan.

- Data and signal MCQs.
- Amplitude, frequency, and phase MCQs.
- Time-domain graph plots MCQs.
- Frequency-domain graph plots MCQs.
- Spectrum ,bandwidth of a signa MCQs.
- Bit rate (number of bits per second) and bit interval (duration of 1 bit) MCQs.
- Nyquist formula MCQs.
- Shannon capacity MCQs.
- Attenuation, distortion, and noise MCQs.
- Throughput, propagation speed, and propagation time ,wavelength of a frequency MCQs.

#### 1. Before data can be transmitted, they must be transformed to ________.

- periodic signals
- electromagnetic signals
- aperiodic signals
- low-frequency sine waves

B. electromagnetic signals

#### 2. A periodic signal completes one cycle in 0.001 s. What is the frequency?

- 1 Hz
- 100 Hz
- 1 KHz
- 1 MHz

C. 1 KHz

#### 3. In a frequency-domain plot, the horizontal axis measures the ________.

- peak amplitude
- frequency
- phase
- slope

B. frequency

#### 4. In a time-domain plot, the horizontal axis is a measure of ________.

- signal amplitude
- frequency
- phase
- time

D. time

#### 5. If the bandwidth of a signal is 5 KHz and the lowest frequency is 52 KHz, what is the highest frequency?

- 5 KHz
- 10 KHz
- 47 KHz
- 57 KHz

D. 57 KHz

#### 6. What is the bandwidth of a signal that ranges from 1 MHz to 4 MHz?

- 4 MHz
- 1 KHz
- 3 MHz
- none of the above

C. 3 MHz

#### 7. As frequency increases, the period ________.

- decreases
- increases
- remains the same
- doubles

A. decreases

#### 8. 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.

- one-half
- twice
- the same as
- indeterminate from

B. twice

#### 9. A sine wave is ________.

- periodic and continuous
- aperiodic and continuous
- periodic and discrete
- aperiodic and discrete

A. periodic and continuous

#### 10. If the maximum amplitude of a sine wave is 2 V, the minimum amplitude is ________ V.

- 2
- 1
- -2
- between -2 and 2

C. -2

#### 11. A signal is measured at two different points. The power is *P*_{1} at the first point and *P*_{2} at the second point. The dB is 0. This means ________.

- P2 is zero
- P2 equals P1
- P2 is much larger than P1
- P2 is much smaller than P1

B. P2 equals P1

#### 12. ________ is a type of transmission impairment in which the signal loses strength due to the resistance of the transmission medium.

- Attenuation
- Distortion
- Noise
- Decibel

A. Attenuation

#### 13. ________ 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.

- Attenuation
- Distortion
- Noise
- Decibel

B. Distortion

#### 14. ________ is a type of transmission impairment in which an outside source such as crosstalk corrupts a signal.

- Attenuation
- Distortion
- Noise
- Decibel

C. Noise

#### 15. When propagation speed is multiplied by propagation time, we get the ________.

- throughput
- wavelength of the signal
- distortion factor
- distance a signal or bit has traveled

D. distance a signal or bit has traveled

#### 16. Data can be ________.

- analog
- digital
- (a) or (b)
- none of the above

C. (a) or (b)

#### 17. _______ data are continuous and take continuous values.

- analog
- digital
- (a) or (b)
- none of the above

A. analog

#### 18. _______ data have discrete states and take discrete values.

- Analog
- Digital
- (a) or (b)
- None of the above

B. Digital

#### 19. Signals can be ________

- analog
- digital
- either (a) or (b)
- neither (a) nor (b)

C. either (a) or (b)

#### 20. _____ signals can have an infinite number of values in a range.

- Analog
- Digital
- (a) or (b)
- None of the above

A. Analog

#### 21. _______ signals can have only a limited number of values.

- Analog
- Digital
- (a) or (b)
- None of the above

B. Digital

#### 22. Frequency and period are ______

- inverse of each other
- proportional to each other
- the same
- none of the above

A. inverse of each other

#### 23. _______is the rate of change with respect to time.

- Amplitude
- Time
- Frequency
- Voltage

C. Frequency

#### 24. _______ describes the position of the waveform relative to time 0.

- Frequency
- Phase
- Amplitude
- Voltage

B. Phase

#### 25. A sine wave in the ______ domain can be represented by one single spike in the _____ domain.

- time; frequency
- frequency; time
- time; phase
- phase; time

A. time; frequency

#### 26. A _________ sine wave is not useful in data communications; we need to send a _______ signal.

- composite; single-frequency
- single-frequency; composite
- single-frequency; double-frequency
- none of the above

B. single-frequency; composite

#### 27. The _____ of a composite signal is the difference between the highest and the lowest frequencies contained in that signal

- frequency
- period
- bandwidth
- amplitude

C. bandwidth

#### 28. A(n)_________ signal is a composite analog signal with an infinite bandwidth.

- digital
- analog
- either (a) or (b)
- neither (a) nor (b)

A. digital

#### 29. Baseband transmission of a digital signal is possible only if we have a ____ channel

- low-pass
- bandpass
- low rate
- high rate

A. low-pass

#### 30. If the available channel is a ____ channel, we cannot send a digital signal directly to the channel

- low-pass
- bandpass
- low rate
- high rate

B. bandpass