Analog Communication 1

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Electronic Engineering MCQ Question Papers: ENTC, IT Interview Placement

Subject:  Analog Communication 1

Part 1: List for questions and answers of Analog Communication

 

Q1. In Pulse Position Modulation, the drawbacks are

a) Synchronization is required between transmitter and receiver

b) Large bandwidth is required as compared to PAM

c) None of the above

d) Both a and b

 

Q2. In PWM signal reception, the Schmitt trigger circuit is used

a) To remove noise

b) To produce ramp signal

c) For synchronization

d) None of the above

 

Q3. In pulse width modulation,

a) Synchronization is not required between transmitter and receiver

b) Amplitude of the carrier pulse is varied

c) Instantaneous power at the transmitter is constant

d) None of the above

 

Q4. In different types of Pulse Width Modulation,

a) Leading edge of the pulse is kept constant

b) Tail edge of the pulse is kept constant

c) Centre of the pulse is kept constant

d) All of the above

 

Q5. In Pulse time modulation (PTM),

a) Amplitude of the carrier is constant

b) Position or width of the carrier varies with modulating signal

c) Pulse width modulation and pulse position modulation are the types of PTM

d) All of the above

 

Q6. Drawback of using PAM method is

a) Bandwidth is very large as compared to modulating signal

b) Varying amplitude of carrier varies the peak power required for transmission

c) Due to varying amplitude of carrier, it is difficult to remove noise at receiver

d) All of the above 

 

Q7. Pulse time modulation (PTM) includes

a) Pulse width modulation

b) Pulse position modulation

c) Pulse amplitude modulation

d) Both a and b

 

Q8. In pulse amplitude modulation,

a) Amplitude of the pulse train is varied

b) Width of the pulse train is varied

c) Frequency of the pulse train is varied

d) None of the above

 

Q9. Types of analog pulse modulation systems are

a) Pulse amplitude modulation

b) Pulse time modulation

c) Frequency modulation

d) Both a and b

 

Q10. The sampling technique having the minimum noise interference is

a) Instantaneous sampling

b) Natural sampling

c) Flat top sampling

d) All of the above

 

Q11. The instantaneous sampling

a) Has a train of impulses

b) Has the pulse width approaching zero value

c) Has the negligible power content

d) All of the above

 

Q12. The techniques used for sampling are

a) Instantaneous sampling

b) Natural sampling

c) Flat top sampling

d) All of the above

 

Q13. A low pass filter is

a) Passes the frequencies lower than the specified cut off frequency

b) Rejects higher frequencies

c) Is used to recover signal from sampled signal

d) All of the above 

 

Q14. Calculate the Nyquist rate for sampling when a continuous time signal is given by

x(t) = 5 cos 100 pt +10 cos 200 pt – 15 cos 300 pt

a) 300Hz

b) 600Hz

c) 150Hz

d) 200Hz

 

Q15. Calculate the minimum sampling rate to avoid aliasing when a continuous time signal is given by 

 x(t) = 5 cos 400 pt

a) 100 Hz

b) 200 Hz

c) 400 Hz

d) 250 Hz

 

Q16. A distorted signal of frequency fm is recovered from a sampled signal if the sampling frequency fs is

a) fs > 2fm

b) fs less than 2fm

c) fs = 2fm

d) fs > and equal 2fm

 

Q17. The desired signal of maximum frequency wm centered at frequency w=0 may be recovered if

a) The sampled signal is passed through low pass filter

b) Filter has the cut off frequency wm

c) Both a and b

d) None of the above

 

Q18. The spectrum of the sampled signal may be obtained without overlapping only if

a) fs > and equal 2fm

b) fs is less than 2fm

c) fs is greater than fm

d) fs is less than fm

 

Q19. The rms value of thermal noise voltage is related to Boltzmann’s constant k as

a) Vn is Directly proportional to k^2

b) Vn is Directly proportional to k

c) Vn is Directly proportional to squre root of k

d) Vn is Directly proportional to k^3 

 

Q20. Threshold effect is:

a) Reduction in output signal to noise ratio

b) Large noise as compared to input signal to envelope detector

c) Detection of message signal is difficult

d) All of the above 

 

Part 1: List for questions and answers of Analog Communication

 

Q1. Answer: b

 

Q2. Answer: a

 

Q3. Answer: a

 

Q4. Answer: d

 

Q5. Answer: d

 

Q6. Answer: d

 

Q7. Answer: d

 

Q8. Answer: a

 

Q9. Answer: d

 

Q10. Answer: b

 

Q11. Answer: d

 

Q12. Answer: d

 

Q13. Answer: d

 

Q14. Answer: a

 

Q15. Answer: c

 

Q16. Answer: b

 

Q17. Answer: c

 

Q18. Answer: a

 

Q19. Answer: c

 

Q20. Answer: d