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ECE :: Communication Systems

Communication Systems - Section 1
Communication Systems - Section 2
Communication Systems - Section 3
Communication Systems - Section 4
Communication Systems - Section 5
Communication Systems - Section 6
Communication Systems - Section 7
Communication Systems - Section 8
Communication Systems - Section 9
Communication Systems - Section 10
Communication Systems - Section 11
Communication Systems - Section 12
Communication Systems - Section 13
Communication Systems - Section 14
Communication Systems - Section 15
Communication Systems - Section 16
Communication Systems - Section 17
Communication Systems - Section 18
Communication Systems - Section 19
Communication Systems - Section 20
Communication Systems - Section 21
Communication Systems - Section 22
Communication Systems - Section 23
Communication Systems - Section 24
Communication Systems - Section 25
Communication Systems - section-26
Communication Systems - Section-27

  1. The main systems used for generation of SSB are

    2. A.
    filter method
    B.
    phase cancellation method
    C.
    third method
    D.
    all of the above

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  2. An antenna operates effectively when its dimensions are

    3. A.
    of the order of magnitude of wavelength to be transmitted
    B.
    very small than the magnitude of wavelength to be transmitted
    C.
    very large than the magnitude of wavelength to be transmitted
    D.
    either (a) or (b)

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  3. The mobile unit of a mobile telephone is generally in

    4. A.
    vehicles
    B.
    pocket
    C.
    office
    D.
    vehicle or pocket

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  4. Assertion (A): Water waves are longitudinal but EM waves are transverse

    Reason (R): In an EM wave electric field, magnetic field and propagation are mutually perpendicular.

    5. A.
    Both A and R are correct and R is correct explanation of A
    B.
    Both A and R are correct but R is not correct explanation of A
    C.
    A is correct but R is wrong
    D.
    A is wrong but R is correct

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  5. In a wave the electric field lines are vertical. Then the wave is

    6. A.
    horizontally polarized
    B.
    vertically polarized
    C.
    either (a) or (b)
    D.
    neither (a) nor (b)

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  6. For an RC low pass filter, the relation between noise bandwidth BN and 3-dB bandwidth B3dB is

    7. A.
    B.
    BN = B3-dB
    C.
    D.
    BN = p B3-dB

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  7. In FM and AM the ratio of signal to noise ratio at the detector output least depends upon

    8. A.
    bandwidth
    B.
    transmission
    C.
    carrier frequency
    D.
    modulating frequency

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  8. Which of the following can provide two or more voice circuits with the same carrier?

    9. A.
    SSB
    B.
    Carrier reinsertion
    C.
    Lincompex
    D.
    Independent side band system

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  9. A linear diode detector uses RC filter. As modulation index increases the maximum permissible value of time constant RC

    10. A.
    increases
    B.
    decreases
    C.
    remains constant
    D.
    either (a) or (c)

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  10. In SSB generation, the most commonly used filter is

    11. A.
    low pass
    B.
    RC
    C.
    LC
    D.
    mechanical

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