Computer Networking – Physical Layer and Transmission Media MCQs

1. As frequency increases, the period ________.

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

3. ________ 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.

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

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

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

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

8. For a ______ channel, the Nyquist bit rate formula defines the theoretical maximum bit rate.

9. For a ______ channel, we need to use the Shannon capacity to find the maximum bit rate.

10. _________ can impair a signal.

11. The _________ product defines the number of bits that can fill the link.

12. Polar and bipolar encoding are types of _______ coding.

13. ___________ conversion involves three techniques: line coding, block coding, and scrambling.

14. In ______ schemes, the voltage level oscillates between a positive and a negative values although it may remain at zero level between the two values.

15. In _____, the level of the voltage determines the value of the bit.

16. In ______, the change or lack of change in the level of the voltage determines the value of the bit.

17. The idea of RZ and the idea of NRZ-L are combined into the ________ scheme.

18. The idea of RZ and the idea of NRZ-I are combined into the ________ scheme.

19. In Manchester and differential Manchester encoding, the transition at the middle of the bit is used for __________.

20. In _______ encoding, we use three levels: positive, zero, and negative.

21. The _____ scheme uses data patterns of size 2 and encodes the 2-bit patterns as one signal element belonging to a four-level signal.

22. _______ encoding has a transition at the middle of each bit.

23. _______ encoding has a transition at the beginning of each 0 bit.

24. Which of the following encoding methods does not provide for synchronization?

25. Which encoding method uses alternating positive and negative values for 1s?

26. Block coding can help in _______ and _________ at the receiver.

27. ________ is the process of converting digital data to a digital signal.

28. _______ provides redundancy to ensure synchronization and inherent error detection.

29. ________ is normally referred to as mB/nB coding; it replaces each m-bit group with an n-bit group.

30. ________ provides synchronization without increasing the number of bits.

31. Two common scrambling techniques are ________.

32. PCM is an example of _______ conversion.

33. The most common technique to change an analog signal to digital data is called __________.

34. The first step in PCM is ________.

35. ______ finds the value of the signal amplitude for each sample; ____ finds the change from the previous sample.

36. The ________ rate defines the number of data elements sent in one second; the ______ rate is the number of signal elements sent in one second.

37. ASK, PSK, FSK, and QAM are examples of ________ conversion.

38. AM, FM, and PM are examples of ________ conversion.

39. In QAM, both ________ of a carrier frequency are varied.

40. In ________, the amplitude of the carrier signal is varied to create signal elements. Both frequency and phase remain constant.

41. In _________, the frequency of the carrier signal is varied to represent data. Both peak amplitude and phase remain constant.

42. In ________, the phase of the carrier is varied to represent two or more different signal elements. Both peak amplitude and frequency remain constant.

43. Quadrature amplitude modulation (QAM) is a combination of ___________.

44. ________ uses two carriers, one in-phase and the other quadrature.

45. How many carrier frequencies are used in BASK?

46. How many carrier frequencies are used in BFSK?

47. How many carrier frequencies are used in BPSK?

48. Which of the following is not an analog-to-analog conversion?

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

50. In _____ transmission, the carrier signal is modulated so that its amplitude varies with the changing amplitudes of the modulating signal.

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

52. Which multiplexing technique is used for analog signals?

53. _______ data are continuous and take continuous values.

54. Which multiplexing technique is used for digital signals?

55. _______ data have discrete states and take discrete values.

56. Which multiplexing technique shifts each signal to a different carrier frequency?

57. _____ signals have an infinite number of values in a time interval.

58. Which multiplexing technique involves signals composed of light beams?

59. _______ signals can have only a limited number of values in a time interval.

60. ________ is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link.

61. Frequency and period are ______.

62. ____ is designed to use the high bandwidth capability of fiber-optic cable.

63. ________ is the rate of change with respect to time.

64. ______ is an analog multiplexing technique to combine optical signals.

65. _______ describes the position of the waveform relative to time 0.

66. _____ is a digital process that allows several connections to share the high bandwidth of a link.

67. A simple sine wave can be represented by one single spike in the _____ domain.

68. We can divide ____ into two different schemes: synchronous or statistical.

69. In ________ TDM, each input connection has an allotment in the output even if it is not sending data.

70. In ________ TDM, slots are dynamically allocated to improve bandwidth efficiency.

71. The _______ technique uses M different carrier frequencies that are modulated by the source signal. At one moment, the sign modulates one carrier frequency; at the next moment, the signal modulates another carrier frequency.

72. The ______ technique expands the bandwidth of a signal by replacing each data bit with n bits using a spreading code.

73. Transmission media are usually categorized as _______.

74. Transmission media lie below the _______ layer.

75. _______ cable consists of an inner copper core and a second conducting outer sheath.

76. In fiber optics, the signal is _______ waves.

77. Which of the following is not a guided medium?