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ECE :: Communication Systems

  1. Which of the following is not advantage of FM over AM?

  2. A.
    Noise immunity
    B.
    Capture effect
    C.
    Fidelity
    D.
    Spluttering effect

  3. In single tone FM discriminator (S0/N0) is

  4. A.
    proportional to deviation
    B.
    proportional to cube of deviation
    C.
    proportional to square of deviation
    D.
    none of the above

  5. In a PCM the amplitude levels are transmitted in a 7 unit code. The no. of levels is

  6. A.
    18
    B.
    14
    C.
    128
    D.
    64

  7. In high power AM transmission modulation is done at

  8. A.
    IF stage
    B.
    RF power
    C.
    buffer stage
    D.
    oscillator stage

  9. Which one of the following gives maximum probability of error?

  10. A.
    ASK
    B.
    DPSK
    C.
    FSK
    D.
    PSK

  11. FM has poor efficiency than

  12. A.
    AM
    B.
    AM-SC
    C.
    PAM
    D.
    PCM

  13. The number of spectral component when two sine wave of same frequency multiplied is

  14. A.
    2
    B.
    3
    C.
    D.
    4

  15. Public address systems generally use electret microphones.

  16. A.
    True
    B.
    False

  17. The noise at the input to an ideal frequency detector is white. The detector is operating above threshold. The power spectral density of the noise at the output is

  18. A.
    raised-cosine
    B.
    flat
    C.
    parabolic
    D.
    Gaussian

  19. As regards BCH code, Hamming code and Reed-Solomon code

  20. A.
    BCH and Hamming code are special cases of Reed-Solomon code
    B.
    Reed-Solomon and Hamming code are special cases of BCH code
    C.
    BCH and Reed-Solomon code are special case of Hamming code
    D.
    none of the above