Digital Communications

Baseband Transmission-2

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Which waveform has the feature of error detection?
NRZ-L
RZ-AMI
Manchester coding
Duobinary
Explanation:
Duobinary scheme does error detection without introducing any additional error bits into the data sequence.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
Some of the M-ary waveforms are
PAM
PPM
PDM
All of the mentioned
Explanation:
When we pulse modulate non binary signals we get M-ary waveform. Some of the examples of M-ary waveforms are PAM, PPM, PDM.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
In pulse modulation, reciprocal of T(time) is
Bandwidth
Symbol rate
Signal voltage
None of the mentioned
Explanation:
T is the time period of the signal. In pulse modulation, the symbol rate Rs can be given as reciprocal of T.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
Which waveform type has better noise immunity?
NRZ
RZ
Phase encoded
Multilevel codes
Explanation:
NRZ waveforms has better error performance than RZ signal waveforms.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Which waveform type has the feature of clocking?
Manchester coding
Bbi-p-M
Delay modulation
NRZ-L
Explanation:
In manchester coding transition occurs in the middle of every bit interval. Thus it has a feature of clocking.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
In which waveform one is represented by half bit wide pulse positioned during the first half and zero is represented by half bit wide pulse positioned in the second half?
Bi-p-L
Bi-p-M
Bi-p-S
Delay modulation
Explanation:
In bi-phase-level one is represented by half bit wide pulse positioned during the first half and zero is represented by half bit wide pulse positioned in the second half.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
PCM word size can be described by
Time period
Symbol rate
Number of quantization levels
None of the mentioned
Explanation:
Each analog sample is transformed into PCM word made up of a group of bits. The PCM word size can be described by number of quantization levels allowed for each sample.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Application of phase encoded binary signals are
Optical communication
Magnetic recording
Satellite telemetry
All of the mentioned
Explanation:
Some of the fields where phase encoded waveforms is being used are optical communication, magnetic tape recording, satellite telemetry etc.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
Which waveform scheme introduces bandwidth compression?
Duobinary
Manchester coding
Phase encoded waveform
Multilevel codes
Explanation:
Multilevel codes increases the bandwidth efficiency by reducing the bandwidth utilization for the given data rate.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
Which binary waveform uses three levels?
Bipolar RZ
RZ-AMI
Bipolar RZ & RZ-AMI
None of the mentioned
Explanation:
In PCM waveforms signals generally use two levels. But few signals use three levels such as bipolar RZ, RZ-AMI, dicode, duobinary etc.