Analog Communication 5

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Electronic Engineering MCQ Question Papers: ENTC, IT Interview Placement

Subject:  Analog Communication 5

Part 5: List for questions and answers of Analog Communication


Q1. What is the maximum frequency deviation allowed in commercial FM broadcasting?

a) 100 KHz

b) 75 KHz

c) 15 KHz

d) 120 KHz


Q2. What is the change in the bandwidth of the signal in FM when the modulating frequency increases from 12 KHz to 24KHz?

a) 40 Hz

b) 58 Hz

c) 24 Hz

d) Bandwidth remains unaffected


Q3. According to Carson’s rule, Bandwidth B and modulating frequency fm are related as

a) B = 2(Δ f + fm) Hz

b) B = fm Hz

c) B is less than 2fm Hz

d) B is greater than 2fm Hz


Q4. The audio signal having frequency 500Hz and voltage 2.6V, shows a deviation of 5.2KHz in a Frequency Modulation system. If the audio signal voltage changes to 8.6V, calculate the new deviation obtained

a) 17.2 KHz

b) 19.6 KHz

c) 25.6 KHz

d) 14.6 KHz


Q5. What is the required bandwidth according to the Carson’s rule, when a 100 MHz carrier is modulated with a sinusoidal signal at 1KHz, the maximum frequency deviation being 50 KHz

a) 1 KHz

b) 50 KHz

c) 102 KHz

d) 150 KHz 


Q6. Disadvantages of FM over AM are

a) Prone to selective fading

b) Capture effect

c) Poorer signal to noise ratio at high audio frequencies

d) All of the above


Q7. The modulation index of FM is given by

a) µ = frequency deviation/ modulating frequency

b) µ = modulating frequency /frequency deviation

c) µ = modulating frequency/ carrier frequency

d) µ = carrier frequency / modulating frequency


Q8. Armstrong method is used for the generation of

a) Direct FM

b) Indirect FM




Q9. What is the effect on the deviation d of an FM signal when it is passed through a mixer?

a) Doubles

b) Reduces

c) Becomes half

d) Remains unchanged


Q10. Pre emphasis is done before

a) Before modulation

b) Before transmission

c) Before detection at receiver

d) After detection at receiver


Q11. De emphasis is

a) is restoring of original signal power

b) is done at the detector output of the receiver

c) is the inverse process of Pre emphasis

d) All of the above


Q12. Pre emphasis is done

a) For boosting of modulating signal voltage

b) For modulating signals at higher frequencies

c) In FM before modulation

d) All of the above 


Q13. Amplitude limiter in FM receivers are used to

a) Remove amplitude variations due to noise

b) Filteration

c) Demodulation

d) Amplification


Q14. The standard value for Intermediate frequency (IF) in double conversion FM receivers is

a) 455 KHz

b) 580 KHz

c) 10.7 MHz

d) 50 MHz


Q15. In radio receivers, varactor diodes are used for

a) Tuning

b) Demodulation

c) Mixing

d) None of the above


Q16. Sensitivity is defined as

a) Ability of receiver to amplify weak signals

b) Ability to reject unwanted signals

c) Ability to convert incoming signal into Image Frequency

d) Ability to reject noise


Q17. Drawbacks of Tuned Radio Receiver are

a) Oscillate at higher frequencies

b) Selectivity is poor

c) Bandwidth of the TRF receiver varies with incoming frequency

d) All of the above


Q18. What are the disadvantages of using balanced slope detector for demodulation of FM signal?

a) The detector operates only for small deviation in frequency

b) Low pass filter of the detector produces distortion in the detection

c) Both a and b

d) None of the above 


Q19. Advantage of using direct method for generation of FM signal is

a) It gives high stability to FM signal frequency

b) Distortion free FM signal is generated

c) High power FM generation is possible

d) None of the above


Q20. Drawbacks of using direct method for generation of FM signal are

a) Does not give high stability to FM signal frequency

b) Distorted FM signal is generated due to harmonics of modulating signal

c) Cannot be used for high power FM generation

d) Both a and b 


Part 5: List for questions and answers of Analog Communication


Q1. Answer: b


Q2. Answer: c


Q3. Answer: a


Q4. Answer: a


Q5. Answer: c


Q6. Answer: d


Q7. Answer: a


Q8. Answer: b


Q9. Answer: d


Q10. Answer: a


Q11. Answer: d


Q12. Answer: d


Q13. Answer: a


Q14. Answer: c


Q15. Answer: a


Q16. Answer: a


Q17. Answer: d


Q18. Answer: c


Q19. Answer: c


Q20. Answer: d