Digital Communications

Baseband Transmission-2

Question 1
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 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%
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.
Question 4
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 5
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 6
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 7
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 8
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 9
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 10
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.