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ECE :: Communication Systems

  1. If sound intensity is 8 W/m2, the dB level of this sound is about

  2. A.
    5 dB
    B.
    50 dB
    C.
    129 dB
    D.
    1290 dB

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  3. The distance of a direct broadcasting satellite from earth's surface is about

  4. A.
    1000 km
    B.
    10000 km
    C.
    36000 km
    D.
    55000 km

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  5. Which of the following microphones has an inbuilt amplifier?

  6. A.
    Condenser
    B.
    Moving coil
    C.
    Ribbon
    D.
    Carbon

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  7. UHF range is

  8. A.
    3 to 30 MHz
    B.
    30 to 300 MHz
    C.
    300 to 3000 MHz
    D.
    3000 to 30000 MHz

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  9. In asynchronous TDM, for n signal sources, each frame contains m slots, where m is usually

  10. A.
    Less than n
    B.
    2n
    C.
    n
    D.
    greater than 2n

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  11. How much is contributed by each bit in the code word of a PCM system under uniform and symmetric quantization to the signal to noise ratio?

  12. A.
    3 dB
    B.
    4 dB
    C.
    5 dB
    D.
    6 dB

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  13. Noise which assumes great importance at high frequencies is

  14. A.
    flicker noise
    B.
    Johnson noise
    C.
    transit-time noise
    D.
    shot noise

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  15. Which one is Analog Continuous modulation technique?

  16. A.
    AM
    B.
    DM
    C.
    PAM
    D.
    PCM

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  17. AM transmitter employing low level modulation

  18. A.
    uses class C amplifier for amplification
    B.
    requires higher audio power
    C.
    has a poor efficiency
    D.
    has a higher efficiency

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  19. As the area of a public meeting increases the amplifier power output required increases.

  20. A.
    True
    B.
    False

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