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ECE :: Communication Systems

  1. TV receivers use flyback switched mode power supply because

  2. A.
    it can supply many voltage outputs
    B.
    it does not require a filter choke and is cheap
    C.
    it has very good regulation at all loads
    D.
    both (a) and (c)

  3. SSB stands for

  4. A.
    Single Side Band
    B.
    Suppressed Side Band
    C.
    Single Sound Band
    D.
    Single Sky Band

  5. Assertion (A): In SSB, carrier is suppressed by about 45 dB

    Reason (R): SSB is standard form for radio communication

  6. 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

  7. For a parallel two wire line with both conductors touching each other, the characteristic impedance is about

  8. A.
    300 Ω
    B.
    200 Ω
    C.
    80 Ω
    D.
    24 Ω

  9. Tape recorders use

  10. A.
    cone type loudspeakers
    B.
    horn type loudspeakers
    C.
    either cone type or horn type loudspeakers
    D.
    none of the above

  11. If f is frequency and d is distance, path attenuation a between isotropic antennas is given by

  12. A.
    a = 33 + 20 log f + 20 log d
    B.
    a = 100 + 33 log f + 33 log d
    C.
    D.

  13. In a FM signal, the modulation index increases, then the power

  14. A.
    increases
    B.
    decreases
    C.
    remains constant
    D.
    none of the above

  15. Higher order TDM levels are obtained by

  16. A.
    forming super master groups
    B.
    using A law
    C.
    using μ law
    D.
    dividing pulse width

  17. Assertion (A): In AM, use of SSB reduces the power and bandwidth requirement

    Reason (R): A balanced modulator produces AM with carrier suppressed

  18. 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

  19. Limiter is not essential in the following detector

  20. A.
    foster-Seeley
    B.
    ratio detector
    C.
    balanced
    D.
    none of the above