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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. Which of the following is an indirect way of generating FM?

    2. A.
    Armstrong modulator
    B.
    Varactor diode modulator
    C.
    Reactance FET modulator
    D.
    Reactance bipolar transistor

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  2. When the length of antenna is a whole wavelength

    3. A.
    the radiation at right angles is zero
    B.
    the radiation at right angles is maximum
    C.
    the radiation is zero in all directions
    D.
    the radiation is maximum in all directions

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  3. Circular polarization

    4. A.
    is useful in reducing depolarization effect on received wave
    B.
    involves critical alignment of transmitting and receiving antenna
    C.
    is useful in discrimination between reception of adjacent beams
    D.
    none of the above

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  4. An FM radio receiver which is tuned to a 91.6 MHz broadcast station may receive an image frequency of __________ MHz.

    5. A.
    102.3
    B.
    113
    C.
    70.2
    D.
    80.9

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  5. If S represents the carrier synchronization at the receiver and r represents the bandwidth efficiency, then the correct statement for the coherent binary PSK is

    6. A.
    r = 0.5, S is required
    B.
    r = 1.0, S is required
    C.
    r = 0.5, S is not required
    D.
    r = 1.0, S is not required

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  6. For telegraphy the most commonly used modulation system is

    7. A.
    FSK
    B.
    two tone modulation
    C.
    PCM
    D.
    single tone modulation

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  7. Commercial Frequency deviation of FM is

    8. A.
    70 kHz
    B.
    75 kHz
    C.
    80 kHz
    D.
    65 kHz

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  8. The colour of an object is decided by

    9. A.
    the reflected colour
    B.
    the wavelength transmitted through it
    C.
    reflected colour for opaque object and wavelength transmitted through it for transparent objects
    D.
    none of the above

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  9. In Pulse Code Modulation system

    10. A.
    large bandwidth is required
    B.
    quantising noise can be overcome by companding
    C.
    quantising noise can be reduced by decreasing the number of standard levels
    D.
    suffers from the disadvantage of its incompatibly with TDM

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  10. Waveform shown in figure is that for

    11. A.
    FM
    B.
    PCM
    C.
    AM-DSB
    D.
    AM-SSB

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