adplus-dvertising
81. In ______ schemes, the voltages are on the both sides of the time axis. For example, the voltage level for 0 can be positive and the voltage level for 1 can be negative.
a. polar
b. bipolar
c. unipolar
d. all of the above
Answer: (a).polar

82. In _____, the level of the voltage determines the value of the bit.
a. NRZ-I
b. NRZ-L
c. both (a) and (b)
d. neither (a) nor (b)
Answer: (b).NRZ-L

83. In ______, the change or lack of change in the level of the voltage determines the value of the bit.
a. NRZ-I
b. NRZ-L
c. both (a) and (b)
d. neither (a) nor (b)
Answer: (a).NRZ-I

84. The idea of RZ and the idea of NRZ-L are combined into the ________ scheme.
a. Manchester
b. differential Manchester
c. both (a) and (b)
d. neither (a) nor (b)
Answer: (a).Manchester

85. The idea of RZ and the idea of NRZ-I are combined into the ________ scheme.
a. Manchester
b. differential Manchester
c. both (a) and (b)
d. neither (a) nor (b)
Answer: (b).differential Manchester

86. In _______ encoding, the duration of the bit is divided into two halves. The voltage remains at one level during the first half and moves to the other level in the second half. The transition at the middle of the bit provides synchronization.
a. Manchester
b. differential Manchester
c. both (a) and (b)
d. neither (a) nor (b)
Answer: (c).both (a) and (b)

87. In ___________ there is always a transition at the middle of the bit, but the bit values are determined at the beginning of the bit. If the next bit is 0, there is a transition; if the next bit is 1, there is none.
a. Manchester
b. differential Manchester
c. both (a) and (b)
d. neither (a) nor (b)
Answer: (b).differential Manchester

88. In Manchester and differential Manchester encoding, the transition at the middle of the bit is used for __________.
a. bit transfer
b. baud transfer
c. synchronization
d. none of the above
Answer: (c).synchronization

89. The minimum bandwidth of Manchester and differential Manchester is ____ that of NRZ.
a. the same as
b. twice
c. thrice
d. none of the above
Answer: (b).twice

90. In _______encoding, we use three levels: positive, zero, and negative.
a. unipolar
b. bipolar
c. polar
d. none of the above
Answer: (b).bipolar