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ECE :: Communication Systems

  1. A generator is feeding power to a transmission line of characteristic impedance Z0. The line is terminated in impedance ZL. Standing waves will be set up if

  2. A.
    ZL = Z0
    B.
    ZL < Z0
    C.
    ZL > Z0
    D.
    both (b) and (c)

  3. In sound recording the degree of pre-emphasis is about 6 dB/ octave.

  4. A.
    True
    B.
    False

  5. Space wave may be a direct wave or wave reflected from earth.

  6. A.
    True
    B.
    False

  7. Radio broadcasts are generally

  8. A.
    amplitude modulation
    B.
    frequency modulation
    C.
    both amplitude and frequency modulation
    D.
    neither amplitude nor frequency modulation

  9. If the frequency of a wave 20 Hz, the time period is

  10. A.
    20 secs
    B.
    2 secs
    C.
    0.2 secs
    D.
    0.05 secs

  11. Which of the following is taken as reference antenna for directive gain?

  12. A.
    Half wave dipole
    B.
    Elementary doublet
    C.
    Isotropic
    D.
    Infinitesimal dipole

  13. Push pull amplifier is

  14. A.
    voltage amplifier
    B.
    current amplifier
    C.
    power amplifier
    D.
    none of the above

  15. When the channel is noisy, producing a conditional probability of error p = 0.5; the channel capacity and entropy function would be, respectively,

  16. A.
    1 and 1
    B.
    1 and 0.5
    C.
    0.5 and 1
    D.
    0 and 1

  17. In CCIR-B system, the time between start of one H syn. pulse and next is

  18. A.
    64 μs
    B.
    6.4 μs
    C.
    640 μs
    D.
    0.64 μs

  19. Counterpoise is used in coils having

  20. A.
    high resistivity
    B.
    low resistivity
    C.
    medium resistivity
    D.
    both (b) and (c)