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2024 1044022024 V4 1044022023 1044022023 V2 104402

2024104402

B.Tech 4th Semester Examination, 2024

03 Hours70 marks

Instructions

  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct option / answer the following (Any seven question only):-

Ask AI

  1. Q1.1

    If the carrier of a 100% modulated A.M. wave is suppressed, the power saving will be in percent-

    a)

    50

    b)

    67

    c)

    80

    d)

    100

    Ask AI

  2. Q1.2

    Modulation is the process of-

    a)

    combining audio and radio frequency waves

    b)

    reducing distortion in RF amplifiers

    c)

    generating constant-frequency radio waves

    d)

    improving thermal stability of a system

    Ask AI

  3. Q1.3

    The FM broadcast band is from-

    a)

    88 to 108 MHz

    b)

    88 to 108 kHz

    c)

    1600 kHz to 59.75 MHz

    d)

    88 to 108 GHz

    Ask AI

  4. Q1.4

    The standard intermediate frequency for FM is-

    a)

    10.7 MHz

    b)

    10.7 kHz

    c)

    4.5 MHz

    d)

    4.5 kHz

    Ask AI

  5. Q1.5

    With 100% modulation. ratio of sideband power to total power transmitted in an amplitude-modulated wave is-

    a)

    2/3

    b)

    4/3

    c)

    1/2

    d)

    1/3

    Ask AI

  6. Q1.6

    In an FM signal. as the modulation index increases. the power-

    a)

    increases

    b)

    remains constant

    c)

    decreases

    d)

    None of above

    Ask AI

  7. Q1.7

    The simplex system is a

    a)

    bidirectional communication system

    b)

    multidirectional communication

    c)

    unidirectional communication

    d)

    None of the above

    Ask AI

  8. Q1.8

    In ________ modulation the phase of the carrier signal is modulated by the message signal.

    a)

    pulse

    b)

    amplitude

    c)

    phase

    d)

    frequency

    Ask AI

  9. Q1.9

    In baseband signal the audio frequency signal range is around

    a)

    10-20 kHz

    b)

    5-10 kHz

    c)

    0-20 kHz

    d)

    0-20 MHz

    Ask AI

  10. Q1.10

    In super heterodyne receiver. at high frequency the

    a)

    signal processing should be done

    b)

    signal transmission should be done

    c)

    bandwidth is low

    d)

    Both (i) and (ii)

    Ask AI

Q.2 Solve both questions :

Ask AI

  1. Q2.1

    Draw the block diagram of communication system. Explain the concept of frequency mixing.

    Ask AI

  2. Q2.2

    Explain the function of each block of communication system.

    Ask AI

Q.3 Solve both questions :

Ask AI

  1. Q3.1

    Explain generation of DSB-SC signal with the help of balanced modulator using diodes.

    Ask AI

  2. Q3.2

    Draw the frequency spectrum of DSB-SC modulation with necessary mathematical expressions. Write short note on Pre-Emphasis and De-Emphasis circuits.

    Ask AI

Q.4 Solve both questions :

Ask AI

  1. Q4.1

    Write short note on Pre-Emphasis and De-Emphasis circuits.

    Ask AI

  2. Q4.2

    Draw block diagram of Super-heterodyne AM receiver and explain function of each block.

    Ask AI

Q.5 Solve both questions :

Ask AI

  1. Q5.1

    (i) The maximum peak-to-peak voltage of an AM wave is 12 mV and the minimum voltage is 4mV. Calculate the modulation factor. (ii) An audio signal of 1 KHz is used to modulate a carrier 500 KHZ. Determine side band frequencies and band width required.

    Ask AI

  2. Q5.2

    Describe thermal noise and shot noise.

    Ask AI

Q.6 Solve both questions :

Ask AI

  1. Q6.1

    With block diagram explain the generation of PWM signals.

    Ask AI

  2. Q6.2

    What are the differences between PAM, PWM, and PPM

    Ask AI

Q.7 Solve both questions :

Ask AI

  1. Q7.1

    The output signal from an AM modulator is: $ s(t) = 5\cos(1800\pi t) + 20\cos(2000\pi t) + 5\cos(22000\pi t) $. (a) Determine the modulation index. (b) Determine the ratio of the power in the sidebands to the power in the carrier.

    Ask AI

  2. Q7.2

    Explain (i) Signal to Noise Ratio (ii) Figure of merit.
    Discuss about noise effect in PM and obtain expression for figure of merit.

    Ask AI

Q.8 Solve both questions :

Ask AI

  1. Q8.1

    Define amplitude modulation and describe it in detail with suitable diagrams.

    Ask AI

  2. Q8.2

    Write the difference forms of Amplitude Modulation, what is the efficiency of the AM?

    Ask AI

Q.9 Solve both questions :

Ask AI

  1. Q9.1

    Write short notes our Envelope Detector.

    Ask AI

  2. Q9.2

    Find the overall noise factor for the cascaded noise networks as shown in given figure. [Stage 1: $ N_F = 4dB $, $ G = 15dB $; Stage 2: $ N_F = 6dB $, $ G = 15dB $]

    Question Diagram
    Ask AI

2024V4104402

B.Tech 4th Semester Examination, 2024

03 Hours70 marks

Instructions

  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct option / answer the following (Any seven question only):-

Ask AI

  1. Q1.1

    If the carrier of a 100% modulated A.M. wave is suppressed, the power saving will be in percent-

    a)

    50

    b)

    67

    c)

    80

    d)

    100

    Ask AI

  2. Q1.2

    Modulation is the process of-

    a)

    combining audio and radio frequency waves

    b)

    reducing distortion in RF amplifiers

    c)

    generating constant-frequency radio waves

    d)

    improving thermal stability of a system

    Ask AI

  3. Q1.3

    The FM broadcast band is from-

    a)

    88 to 108 MHz

    b)

    88 to 108 kHz

    c)

    1600 kHz to 59.75 MHz

    d)

    88 to 108 GHz

    Ask AI

  4. Q1.4

    The standard intermediate frequency for FM is-

    a)

    10.7 MHz

    b)

    10.7 kHz

    c)

    4.5 MHz

    d)

    4.5 kHz

    Ask AI

  5. Q1.5

    With 100% modulation. ratio of sideband power to total power transmitted in an amplitude-modulated wave is-

    a)

    2/3

    b)

    4/3

    c)

    1/2

    d)

    1/3

    Ask AI

  6. Q1.6

    In an FM signal. as the modulation index increases. the power-

    a)

    increases

    b)

    remains constant

    c)

    decreases

    d)

    None of above

    Ask AI

  7. Q1.7

    The simplex system is a

    a)

    bidirectional communication system

    b)

    multidirectional communication

    c)

    unidirectional communication

    d)

    None of the above

    Ask AI

  8. Q1.8

    In ________ modulation the phase of the carrier signal is modulated by the message signal.

    a)

    pulse

    b)

    amplitude

    c)

    phase

    d)

    frequency

    Ask AI

  9. Q1.9

    In baseband signal the audio frequency signal range is around

    a)

    10-20 kHz

    b)

    5-10 kHz

    c)

    0-20 kHz

    d)

    0-20 MHz

    Ask AI

  10. Q1.10

    In super heterodyne receiver. at high frequency the

    a)

    signal processing should be done

    b)

    signal transmission should be done

    c)

    bandwidth is low

    d)

    Both (i) and (ii)

    Ask AI

Q.2 Solve both questions :

Ask AI

  1. Q2.1

    Draw the block diagram of communication system. Explain the concept of frequency mixing.

    Ask AI

  2. Q2.2

    Explain the function of each block of communication system.

    Ask AI

Q.3 Solve both questions :

Ask AI

  1. Q3.1

    Explain generation of DSB-SC signal with the help of balanced modulator using diodes.

    Ask AI

  2. Q3.2

    Draw the frequency spectrum of DSB-SC modulation with necessary mathematical expressions. Write short note on Pre-Emphasis and De-Emphasis circuits.

    Ask AI

Q.4 Solve both questions :

Ask AI

  1. Q4.1

    Write short note on Pre-Emphasis and De-Emphasis circuits.

    Ask AI

  2. Q4.2

    Draw block diagram of Super-heterodyne AM receiver and explain function of each block.

    Ask AI

Q.5 Solve both questions :

Ask AI

  1. Q5.1

    (i) The maximum peak-to-peak voltage of an AM wave is 12 mV and the minimum voltage is 4mV. Calculate the modulation factor. (ii) An audio signal of 1 KHz is used to modulate a carrier 500 KHZ. Determine side band frequencies and band width required.

    Ask AI

  2. Q5.2

    Describe thermal noise and shot noise.

    Ask AI

Q.6 Solve both questions :

Ask AI

  1. Q6.1

    With block diagram explain the generation of PWM signals.

    Ask AI

  2. Q6.2

    What are the differences between PAM, PWM, and PPM

    Ask AI

Q.7 Solve both questions :

Ask AI

  1. Q7.1

    The output signal from an AM modulator is: $ s(t) = 5\cos(1800\pi t) + 20\cos(2000\pi t) + 5\cos(22000\pi t) $. (a) Determine the modulation index. (b) Determine the ratio of the power in the sidebands to the power in the carrier.

    Ask AI

  2. Q7.2

    Explain (i) Signal to Noise Ratio (ii) Figure of merit.
    Discuss about noise effect in PM and obtain expression for figure of merit.

    Ask AI

Q.8 Solve both questions :

Ask AI

  1. Q8.1

    Define amplitude modulation and describe it in detail with suitable diagrams.

    Ask AI

  2. Q8.2

    Write the difference forms of Amplitude Modulation, what is the efficiency of the AM?

    Ask AI

Q.9 Solve both questions :

Ask AI

  1. Q9.1

    Write short notes our Envelope Detector.

    Ask AI

  2. Q9.2

    Find the overall noise factor for the cascaded noise networks as shown in given figure. [Stage 1: $ N_F = 4dB $, $ G = 15dB $; Stage 2: $ N_F = 6dB $, $ G = 15dB $]

    Question Diagram
    Ask AI

2023104402

B.Tech 4th Semester Examination, 2023

03 Hours70 marks

Instructions

  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer of the following (Any seven question only):

Ask AI

  1. Q1.1

    In NBFM, the modulation index is close to

    a)

    1

    b)

    10

    c)

    greater than 1

    d)

    infinite

    Ask AI

  2. Q1.2

    The maximum power efficiency of an AM modulator is

    a)

    50%

    b)

    25%

    c)

    75%

    d)

    100%

    Ask AI

  3. Q1.3

    Spectral density of white noise is

    a)

    Varies with frequency

    b)

    Constant

    c)

    Varies with bandwidth

    d)

    Varies with amplitude

    Ask AI

  4. Q1.4

    If the step size of a system is 0.0721, find its quantization power?

    a)

    3.25×10−33.25 \times 10^{-3}

    b)

    4.33×10−34.33 \times 10^{-3}

    c)

    4.33×10−44.33 \times 10^{-4}

    d)

    3.25×10−23.25 \times 10^{-2}

    Ask AI

  5. Q1.5

    Which of the following frequency is not transmitted in AM transmission?

    a)

    Upper side band frequency

    b)

    Carrier frequency

    c)

    Lower side band frequency

    d)

    Audio frequency

    Ask AI

  6. Q1.6

    What is the use of Companding?

    a)

    in PCM transmitters to allow amplitude limiting in the receivers

    b)

    in PCM receiver to overcome impulse noise

    c)

    to overcome quantizing noise in PCM

    d)

    to protect small signals in PCM from quantizing distortion

    Ask AI

  7. Q1.7

    Envelope Detector is a/an

    a)

    Coherent detector

    b)

    Asynchronous Detector

    c)

    Synchronous Detector

    d)

    Product Demodulator

    Ask AI

  8. Q1.8

    A 1000KHz carrier is modulated by 100Hz and 200Hz waves, then which of the following frequencies cannot be present at the output?

    a)

    1000.1 KHz

    b)

    999.9 KHz

    c)

    1000.2 KHz

    d)

    999.7 KHz

    Ask AI

  9. Q1.9

    For 100% modulation, power in each sideband is _____ of that of carrier.

    a)

    50%

    b)

    60%

    c)

    25%

    d)

    33.33%

    Ask AI

  10. Q1.10

    The frequency of local oscillator

    a)

    can be either below or above the RF frequency

    b)

    is below the RF frequency

    c)

    is above the RF frequency

    d)

    is fixed typically at 450KHz

    Ask AI

Q.2 Solve this question :

Ask AI

  1. Q2.1

    A radio receiver with equivalent noise bandwidth of 10kHz has a noise figure of 20dB.If input SNR to receiver is 40dB, determine the output SNR. What is equivalent noise temperature if ambient temperature is 27°C.

    Ask AI

Q.3 Solve this question :

Ask AI

  1. Q3.1

    Discuss the Armstrong method for the generation of wideband FM.

    Ask AI

Q.4 Solve both questions :

Ask AI

  1. Q4.1

    Explain the working of slope detector method used for demodulation.

    Ask AI

  2. Q4.2

    Write notes on PAM, PPM and PWM.

    Ask AI

Q.5 Solve both questions :

Ask AI

  1. Q5.1

    Explain need of modulation and its advantage.

    Ask AI

  2. Q5.2

    Derive the expression for power content in an AM wave.

    Ask AI

Q.6 Solve this question :

Ask AI

  1. Q6.1

    When a super-heterodyne receiver is tuned to 600kHz,its local oscillator provides the mixer with an input at 1055 kHz. What is the image frequency? The antenna of the receiver is connected to the mixer via a tuned circuit with Q 50. What will be the rejection ratio for the calculated image frequency?

    Ask AI

Q.7 Solve this question :

Ask AI

  1. Q7.1

    What is demodulation? Explain square law demodulator.

    Ask AI

Q.8 Solve this question :

Ask AI

  1. Q8.1

    Derive the expression of AM modulated wave and draw its waveform.

    Ask AI

Q.9 Write short notes on any two of the following:

Ask AI

  1. Q9.1

    a)

    Thermal Noise and Shot Noise & Carson Rule.

    b)

    DSB-SC & VSB

    c)

    Difference between Analog & Digital communication

    d)

    Synchronous detection of DSB-SC

    Ask AI

2023V2104402

B.Tech 4th Semester Examination, 2023

03 Hours70 marks

Instructions

  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer of the following (Any seven question only):

Ask AI

  1. Q1.1

    In NBFM, the modulation index is close to

    a)

    1

    b)

    10

    c)

    greater than 1

    d)

    infinite

    Ask AI

  2. Q1.2

    The maximum power efficiency of an AM modulator is

    a)

    50%

    b)

    25%

    c)

    75%

    d)

    100%

    Ask AI

  3. Q1.3

    Spectral density of white noise is

    a)

    Varies with frequency

    b)

    Constant

    c)

    Varies with bandwidth

    d)

    Varies with amplitude

    Ask AI

  4. Q1.4

    If the step size of a system is 0.0721, find its quantization power?

    a)

    3.25×10−33.25 \times 10^{-3}

    b)

    4.33×10−34.33 \times 10^{-3}

    c)

    4.33×10−44.33 \times 10^{-4}

    d)

    3.25×10−23.25 \times 10^{-2}

    Ask AI

  5. Q1.5

    Which of the following frequency is not transmitted in AM transmission?

    a)

    Upper side band frequency

    b)

    Carrier frequency

    c)

    Lower side band frequency

    d)

    Audio frequency

    Ask AI

  6. Q1.6

    What is the use of Companding?

    a)

    in PCM transmitters to allow amplitude limiting in the receivers

    b)

    in PCM receiver to overcome impulse noise

    c)

    to overcome quantizing noise in PCM

    d)

    to protect small signals in PCM from quantizing distortion

    Ask AI

  7. Q1.7

    Envelope Detector is a/an

    a)

    Coherent detector

    b)

    Asynchronous Detector

    c)

    Synchronous Detector

    d)

    Product Demodulator

    Ask AI

  8. Q1.8

    A 1000KHz carrier is modulated by 100Hz and 200Hz waves, then which of the following frequencies cannot be present at the output?

    a)

    1000.1 KHz

    b)

    999.9 KHz

    c)

    1000.2 KHz

    d)

    999.7 KHz

    Ask AI

  9. Q1.9

    For 100% modulation, power in each sideband is _____ of that of carrier.

    a)

    50%

    b)

    60%

    c)

    25%

    d)

    33.33%

    Ask AI

  10. Q1.10

    The frequency of local oscillator

    a)

    can be either below or above the RF frequency

    b)

    is below the RF frequency

    c)

    is above the RF frequency

    d)

    is fixed typically at 450KHz

    Ask AI

Q.2 Solve this question :

Ask AI

  1. Q2.1

    A radio receiver with equivalent noise bandwidth of 10kHz has a noise figure of 20dB.If input SNR to receiver is 40dB, determine the output SNR. What is equivalent noise temperature if ambient temperature is 27°C.

    Ask AI

Q.3 Solve this question :

Ask AI

  1. Q3.1

    Discuss the Armstrong method for the generation of wideband FM.

    Ask AI

Q.4 Solve both questions :

Ask AI

  1. Q4.1

    Explain the working of slope detector method used for demodulation.

    Ask AI

  2. Q4.2

    Write notes on PAM, PPM and PWM.

    Ask AI

Q.5 Solve both questions :

Ask AI

  1. Q5.1

    Explain need of modulation and its advantage.

    Ask AI

  2. Q5.2

    Derive the expression for power content in an AM wave.

    Ask AI

Q.6 Solve this question :

Ask AI

  1. Q6.1

    When a super-heterodyne receiver is tuned to 600kHz,its local oscillator provides the mixer with an input at 1055 kHz. What is the image frequency? The antenna of the receiver is connected to the mixer via a tuned circuit with Q 50. What will be the rejection ratio for the calculated image frequency?

    Ask AI

Q.7 Solve this question :

Ask AI

  1. Q7.1

    What is demodulation? Explain square law demodulator.

    Ask AI

Q.8 Solve this question :

Ask AI

  1. Q8.1

    Derive the expression of AM modulated wave and draw its waveform.

    Ask AI

Q.9 Write short notes on any two of the following:

Ask AI

  1. Q9.1

    • Thermal Noise and Shot Noise & Carson Rule.
    • DSB-SC & VSB
    • Difference between Analog & Digital communication
    • Synchronous detection of DSB-SC
    a)

    Thermal Noise and Shot Noise & Carson Rule.

    b)

    DSB-SC & VSB

    c)

    Difference between Analog & Digital communication

    d)

    Synchronous detection of DSB-SC

    Ask AI

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