Digital Communication 2

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Electronic Engineering MCQ Question Papers: ENTC, IT Interview Placement

Subject: Digital Communication 2

Part 2: List for questions and answers of Digital Communication


Q1. The digital modulation scheme in which the step size is not fixed is

a) Delta modulation

b) Adaptive delta modulation


d) PCM


Q2. In Adaptive Delta Modulation, the slope error reduces and

a) Quantization error decreases

b) Quantization error increases

c) Quantization error remains same

d) None of the above


Q3. The number of voice channels that can be accommodated for transmission in T1 carrier system is

a) 24

b) 32

c) 56

d) 64


Q4. The maximum data transmission rate in T1 carrier system is

a) 2.6 megabits per second

b) 1000 megabits per second

c) 1.544 megabits per second

d) 5.6 megabits per second


Q5. T1 carrier system is used

a) For PCM voice transmission

b) For delta modulation

c) For frequency modulated signals

d) None of the above


Q6. Matched filter may be optimally used only for

a) Gaussian noise

b) Transit time noise

c) Flicker

d) All of the above 


Q7. Characteristics of Matched filter are

a) Matched filter is used to maximize Signal to noise ratio even for non Gaussian noise

b) It gives the output as signal energy in the absence of noise

c) They are used for signal detection

d) All of the above


Q8. Matched filters may be used

a) To estimate the frequency of the received signal

b) In parameter estimation problems

c) To estimate the distance of the object

d) All of the above


Q9. The process of coding multiplexer output into electrical pulses or waveforms for transmission is called

a) Line coding

b) Amplitude modulation

c) FSK

d) Filtering


Q10. For a line code, the transmission bandwidth must be

a) Maximum possible

b) As small as possible

c) Depends on the signal

d) None of the above


Q11. Regenerative repeaters are used for

a) Eliminating noise

b) Reconstruction of signals

c) Transmission over long distances

d) All of the above


Q12. Scrambling of data is

a) Removing long strings of 1’s and 0’s

b) Exchanging of data

c) Transmission of digital data

d) All of the above 


Q13. In polar RZ format for coding, symbol ‘0’ is represented by

a) Zero voltage

b) Negative voltage

c) Pulse is transmitted for half the duration

d) Both b and c are correct


Q14. In a uni-polar RZ format,

a) The waveform has zero value for symbol ‘0’

b) The waveform has A volts for symbol ‘1’

c) The waveform has positive and negative values for ‘1’ and ‘0’ symbol respectively

d) Both a and b are correct


Q15. Polar coding is a technique in which

a) 1 is transmitted by a positive pulse and 0 is transmitted by negative pulse

b) 1 is transmitted by a positive pulse and 0 is transmitted by zero volts

c) Both a & b

d) None of the above


Q16. The polarities in NRZ format use

a) Complete pulse duration

b) Half duration

c) Both positive as well as negative value

d) Each pulse is used for twice the duration


Q17. The format in which the positive half interval pulse is followed by a negative half interval pulse for transmission of ‘1’ is

a) Polar NRZ format

b) Bipolar NRZ format

c) Manchester format

d) None of the above


Q18. The maximum synchronizing capability in coding techniques is present in

a) Manchester format

b) Polar NRZ

c) Polar RZ

d) Polar quaternary NRZ 


Q19. The advantage of using Manchester format of coding is

a) Power saving

b) Polarity sense at the receiver

c) Noise immunity

d) None of the above


Q20. Alternate Mark Inversion (AMI) is also known as

a) Pseudo ternary coding

b) Manchester coding

c) Polar NRZ format

d) None of the above 


Part 2: List for questions and answers of Digital Communication


Q1. Answer: b


Q2. Answer: c


Q3. Answer: a


Q4. Answer: c


Q5. Answer: a


Q6. Answer: a


Q7. Answer: d


Q8. Answer: d


Q9. Answer: a


Q10. Answer: b


Q11. Answer: d


Q12. Answer: a


Q13. Answer: d


Q14. Answer: d


Q15. Answer: a


Q16. Answer: a


Q17. Answer: c


Q18. Answer: a


Q19. Answer: a


Q20. Answer: a