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ECE :: Communication Systems

  1. The FM broadcast band is from

  2. A.
    550 to 1600 kHz
    B.
    88 to 108 kHz
    C.
    88 to 108 MHz
    D.
    1600 kHz to 59.75 MHz

  3. If k is Boltzmann's constant, T0 is standard ambient temperature, δf is bandwidth of receiver, F is noise figure, the minimum receivable signal in a radar receiver is given by

  4. A.
    k T0f)(F)
    B.
    k T0f)(F - 1)
    C.
    D.
    none of the above

  5. The purpose of source coding is to

  6. A.
    increase the information transmission rate
    B.
    decrease ratio
    C.
    decrease the information transmission rate
    D.
    decrease probability of error

  7. If a source of information generates messages at the rate of r messages per second and H is entropy, the information rate is

  8. A.
    B.
    C.
    rH
    D.

  9. The noise generated by a resistor depends upon

  10. A.
    its operating temperature
    B.
    its resistance value
    C.
    both (a) and (b)
    D.
    bandwidth

  11. A source has two symbols x1 and x2 with probabilities pi and pr. If a new source with four symbols is generated from the above source, the new symbol probabilities will be (∈ is a number such that 0 < ∈ < 1)

  12. A.
    p1, p2, p1, p2
    B.
    p1, p1, p2, p2
    C.
    (1 - ∈)p1, (1 - ∈) p2, p1, p2
    D.

  13. Coupling and bypass filters can be a source of

  14. A.
    low-frequency parasitics
    B.
    high-frequency parasitics
    C.
    carrier frequency parasitics
    D.
    none of the above

  15. Assertion (A): SSB transmitter is generally smaller than AM transmitter

    Reason (R): SSB systems mostly use combined transmitter receiver.

  16. 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

  17. The VLF, LF and MF antennas are

  18. A.
    horizontally polarized
    B.
    vertically polarized
    C.
    non linearly polarized
    D.
    either (a) or (b)