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ECE :: Communication Systems

  1. In frequency modulation noise can be further reduced by

  2. A.
    increasing deviation
    B.
    reducing deviation
    C.
    reducing carrier frequency
    D.
    increasing signal amplitude

  3. Which one of the following is digital?

  4. A.
    Pulse code modulation
    B.
    Pulse width modulation
    C.
    Pulse frequency modulation
    D.
    Pulse position modulation

  5. Automatic sensitivity control by target voltage control is easily possible in

  6. A.
    Vidicon
    B.
    Plumbicon
    C.
    New vicon
    D.
    both (b) and (c)

  7. Pick the odd one out

  8. A.
    PPM
    B.
    PDM
    C.
    PWM
    D.
    PLM

  9. In a colour TV receiver SAW filter consists of

  10. A.
    piezoelectric substrate on which are deposited two inter, digital transducers
    B.
    photo conductive substrate which are deposited two inter digital transducers
    C.
    photo voltaic substrate which are deposited two inter digital transducers
    D.
    photo resistive substrate which are deposited two inter digital transducers

  11. Diffraction of EM waves

  12. A.
    arises only with spherical wave front
    B.
    may occur around the edge of an obstacle
    C.
    occurs when waves pass through a big slot
    D.
    none of the above

  13. The start of modern computer age was started by the event

  14. A.
    development of disc drive
    B.
    development of transistor
    C.
    development of Hollerith code
    D.
    design of EVIAC computer

  15. At night D layer of ionosphere is absent.

  16. A.
    True
    B.
    False

  17. Which of the following is not correct?

  18. A.
    In SSB amplitude modulated system, the transmitter circuit has to be more stable leading to better reception
    B.
    In SSB amplitude modulated system more channel space is available as compared to double sideband amplitude modulated system
    C.
    In SSB amplitude modulated system the signal is more noise resistant as compared to double sideband system
    D.
    An SSB-AM system requires lesser power (for the same signal strength) as compared to DSB-AM system

  19. Assertion (A): Data communication using digital data must be very accurate.

    Reason (R): In analog signals redundancy is available but in digital signals redundancy is not available.

  20. A.
    Both A and R are correct and R is correct explanation of A
    B.
    Both A and R are correct but R is not correct explanation of A
    C.
    A is correct but R is wrong
    D.
    A is wrong but R is correct