# Data Communication and Networking – Digital to Digital Encoding Methods – Unipolar / Bipolar / Polar MCQs A+ A  A-

This set of Data communication and Networking Multiple Choice Questions and Answers (MCQs) focuses on “Digital to Digital Encoding Methods- Unipolar – Bipolar – Polar”.

1. Unipolar
2. Bipolar
3. Polar
1. NRZ
1. NRZ-L
2. NRZ-I
2. RZ
3. Biphase
1. Manchester
2. Differential Manchester

1
. In _______ encoding one amplitude represents a 1 bit and zero amplitude represents a 0 bit (or vice versa).
• unipolar
• polar
• bipolar
• b and c
2
. In _______ encoding positive and negative amplitudes represent the bits
• unipolar
• polar
• bipolar
• b and c
3
. In _______ encoding positive, negative, and zero amplitudes represent the bits
• unipolar
• polar
• bipolar
• b and c
4
. A digital signal has its 0 bits represented by 0 volts and its 1 bit represented by 5 volts. This is _______ encoding.
• unipolar
• polar
• bipolar
• b and c
5
. A digital signal has its 0 bits represented by 0 volts and its 1 bit represented by -5 volts or 5 volts. This is _______ encoding
• unipolar
• polar
• bipolar
• b and c
6
. A digital signal has its 0 bits represented by -5 volts and its 1 bit represented by 5. This is _______ encoding
• unipolar
• polar
• bipolar
• b and c
7
. The DC component is a serious problem for _______ encoding
• unipolar
• polar
• bipolar
• b and c
8
. Unipolar encoding has a DC component because the average _______ of the signal is nonzero
• amplitude
• frequency
• phase
• period
9
. NRZ-L is a _______ encoding method.
• unipolar
• polar
• bipolar
• none of the above
10
. NRZ-I is a _______ encoding method.
• unipolar
• polar
• bipolar
• none of the above
11
. RZ is a _______ encoding method.
• unipolar
• polar
• bipolar
• none of the above
12
. Manchester encoding is a _______ encoding method
• unipolar
• polar
• bipolar
• none of the above
13
. Differential Manchester encoding is a _______ encoding method.
• unipolar
• polar
• bipolar
• none of the above
14
. AMI is a _______ encoding method
• unipolar
• polar
• bipolar
• none of the above
15
. B8ZS is a _______ encoding method.
• unipolar
• polar
• bipolar
• none of the above
16
. HDB3 is a _______ encoding method.
• unipolar
• polar
• bipolar
• none of the above
17
. _______ encoding is superior to _______ encoding because the problem of the DC component is alleviated
• Unipolar; polar
• Polar; bipolar
• Polar; unipolar
• Unipolar; bipolar
18
. Ethernet LANs use _______ encoding
• RZ
• Manchester
• differential Manchester
• NRZ-I
19
. Token Ring LANs use _______ encoding
• RZ
• Manchester
• differential Manchester
• NRZ-I
20
. In _______ encoding the transition between a positive and a negative voltage represents a 1 bit
• NRZ-I
• NRZ-L
• Manchester
• differential Manchester
21
. In _______ encoding halfway through each bit interval, the signal returns to zero.
• NRZ-I
• NRZ-L
• RZ
• Manchester
22
. RZ encoding requires _______ signal change(s) to encode one bit.
• no
• one
• two
• three
23
. Manchester and differential Manchester encoding are both types of _______ encoding
• unipolar
• NRZ
• biphase
• bipolar
24
. Which of the following is not a type of bipolar encoding?
• AMI
• RZ
• B8ZS
• HDB3
25
. The DC component problem is handled in AMI through _______
• transitions at the beginning of each bit interval
• transitions at the middle of each bit interval
• alternate positive and negative amplitudes for the 1 bits
• alternate positive and negative amplitudes for the 0 bits
26
. The DC component problem is handled in pseudoternary AMI through _______
• transitions at the beginning of each bit interval
• transitions at the middle of each bit interval
• alternate positive and negative amplitudes for the 1 bits
• alternate positive and negative amplitudes for the 0 bits
27
. The synchronization problem for long streams of 1s is handled in AMI through _______.
• transitions at the beginning of each bit interval
• transitions at the middle of each bit interval
• alternate positive and negative amplitudes for the 1 bits
• alternate positive and negative amplitudes for the 0 bits
28
. AMI is an acronym for _______.
• asynchronous mark inversion
• alternate mark inversion
• active mapped inversion
• alternate mask inversion
29
. _______ is a variation of AMI.
• B8ZS
• HDB3
• UB40
• a and b
30
. _______ is an attempt to synchronize long strings of 0s
• B8ZS
• HDB3
• UB40
• a and b
31
. In _______ encoding, anytime there are eight or more consecutive 0 bits, violations are deliberately introduced
• B8ZS
• HDB3
• HDLC
• B4ZS
32
. In _______ encoding, anytime there are four or more consecutive 0 bits, violations are deliberately introduced
• B8ZS
• HDB3
• HDLC
• B4ZS
33
. _______ encoding is used in North America to provide synchronization of strings of 0s.
• B8ZS
• HDB3
• HDLC
• B4ZS
34
. _______ encoding is used in Europe and Japan to provide synchronization of strings of 0s
• B8ZS
• HDB3
• HDLC
• B4ZS
35
. In B8ZS encoding, a string of eight consecutive 0s produces _______
• one violation
• two violations
• three violations
• any of the above
36
. In HDB3 encoding, a string of four consecutive 0s produces _______.
• one violation
• two violations
• three violations
• any of the above