Communication miscellaneous

Communication miscellaneous

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Communication

Communication miscellaneous
  1. Assuming other parameters unchanged if the modulating frequency is halved in a modulating systems, the modulation index is doubled. The modulation system is—








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    Since modulation index is given by

    β =
    KfAm
    ωm

    given,
    ω'm =
    ωm
    2

    Now,
    β' =
    KfAm
    		 = 2β
    ωm/2

    Hence alternative (B) is the correct choice.
    Since here,
    β ∝
    1
    ωm

    Correct Option: B

    Since modulation index is given by

    β =
    KfAm
    ωm

    given,
    ω'm =
    ωm
    2

    Now,
    β' =
    KfAm
    		 = 2β
    ωm/2

    Hence alternative (B) is the correct choice.
    Since here,
    β ∝
    1
    ωm

  1. Which of the following process is a linear modulation process?








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    NA

    Correct Option: C

    NA

  1. An increase in the modulation index leads increase in bandwidth in case of—








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    Refer synopsis

    Correct Option: B

    Refer synopsis

  1. FM broadcast band lies in—








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    NA

    Correct Option: A

    NA

  1. The threshold in FM depends on—








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    When the carrier to noise ratio is slightly less than unity, the frequency of spike generation is small, and each spike produces individual clicking sound in the receiver. But, when the carrier to noise ratio is further decreased so that the ratio is moderately less than unity, the spikes are generated rapidly and the clicks merge into sputtering sound. This phenomenon is known as threshold effect in FM. and the level of threshold depends upon the frequency deviation and power level of frequencies radiated at the receiver.

    Correct Option: C

    When the carrier to noise ratio is slightly less than unity, the frequency of spike generation is small, and each spike produces individual clicking sound in the receiver. But, when the carrier to noise ratio is further decreased so that the ratio is moderately less than unity, the spikes are generated rapidly and the clicks merge into sputtering sound. This phenomenon is known as threshold effect in FM. and the level of threshold depends upon the frequency deviation and power level of frequencies radiated at the receiver.