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ECE :: Communication Systems

  1. If D is diagonal and F is focal length, lens angle θ is

  2. A.
    θ = tan-1 (D/F)
    B.
    θ = 2 tan-1 (D/F)
    C.
    θ = tan-1 (D/2F)
    D.
    θ = 2 tan-1 (D/2F)

  3. Present day stereophonic systems have

  4. A.
    only CD playback facility
    B.
    only tape playback facility
    C.
    both CD and tape playback facilities along with radio
    D.
    none of the above

  5. RF choke used for suppressing interference in TV is generally

  6. A.
    honey comb wound coil
    B.
    iron core coil
    C.
    single layer coil
    D.
    multilayer coil

  7. Indicate the false statement: To combat noise

  8. A.
    reduce signalling rate
    B.
    increase transmitted power
    C.
    use redundancy
    D.
    increase channel bandwidth

  9. Audio and video signals are called modulating waves.

  10. A.
    True
    B.
    False

  11. In AM, if modulation index is more than 100%, then

  12. A.
    bandwidth increases
    B.
    the wave gets distorted
    C.
    power of the wave increases
    D.
    efficiency of transmission increases

  13. The width of air gap on recording head in a tape recorder is about

  14. A.
    6 micron
    B.
    3 micron
    C.
    1 micron
    D.
    25 micron

  15. In a stereo tape recorder the speed of the tape is

  16. A.
    38 m/s
    B.
    19 m/s
    C.
    9.5 m/s
    D.
    4.75 m/s

  17. Which of the following refers to SSB suppressed carrier amplitude modulated system?

  18. A.
    A3E
    B.
    H3E
    C.
    J3E
    D.
    C3F

  19. The frequency at which the piezoelectric effect occurs is primarily determined by

  20. A.
    the weight of the crystal
    B.
    thickness of the crystal
    C.
    length of the crystal
    D.
    gain structure of the crystal