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ECE :: Communication Systems

Communication Systems - Section 1
Communication Systems - Section 2
Communication Systems - Section 3
Communication Systems - Section 4
Communication Systems - Section 5
Communication Systems - Section 6
Communication Systems - Section 7
Communication Systems - Section 8
Communication Systems - Section 9
Communication Systems - Section 10
Communication Systems - Section 11
Communication Systems - Section 12
Communication Systems - Section 13
Communication Systems - Section 14
Communication Systems - Section 15
Communication Systems - Section 16
Communication Systems - Section 17
Communication Systems - Section 18
Communication Systems - Section 19
Communication Systems - Section 20
Communication Systems - Section 21
Communication Systems - Section 22
Communication Systems - Section 23
Communication Systems - Section 24
Communication Systems - Section 25
Communication Systems - section-26
Communication Systems - Section-27
  1. In Pulse Code Modulation system

    2. A.

     Large bandwidth is required
    B.

     Quantising noise can be overcome by companding
    C.

     Quantising noise can be reduced by decreasing the number of standard levels
    D.

     Suffers from the disadvantage of its incompatibly with TDM

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  2. An audio signal (say from 50 Hz to 10000 Hz) is frequency translated by a carrier having a frequency of 106 Hz. The values of initial (without frequency translation) and final (after frequency translation) fractional change in frequency from one band edge to the other are

    3. A.

     200 and 1.01
    B.

     200 and 10.01
    C.

     200 and 100.1
    D.

     200 and 200

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  3. DVD uses

    4. A.

     Laser beam for both recording and playback
    B.

     Laser beam for recording and video head for playback
    C.

     Video head for recording and laser beam for playback
    D.

     None of the above

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  4. If output power of a radio receiver is doubled, its volume is increased by __________ dB.

    5. A.

     2
    B.

     3
    C.

     1
    D.

     -3

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  5. For attenuation of high frequencies we should use

    6. A.

     Shunt capacitance
    B.

     Series capacitance
    C.

     Inductance
    D.

     Resistance

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  6. The disadvantage of FM over AM is that

    7. A.

     High output power is needed
    B.

     High modulating power is needed
    C.

     Noise is very high for high frequency
    D.

     Large bandwidth is required

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  7. VSB modulation is preferred in TV because

    8. A.

     It reduces the bandwidth requirement to half
    B.

     It avoids phase distortion at low frequencies
    C.

     It results in better reception
    D.

     None of the above

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  8. Which one of the following is analog?

    9. A.

     PCM
    B.

     PWM
    C.

     Delta modulation
    D.

     Differential PCM

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  9. As per Shannon-Hartley theorem, a noise less Gaussian channel has

    10. A.

     Zero capacity
    B.

     Infinite capacity
    C.

     Small capacity
    D.

     None of the above

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  10. In a TV receiver antenna the length of reflector rod

    11. A.

     Is the same as that of dipole
    B.

     Is less than that of dipole
    C.

     Is more than that of dipole
    D.

     May be equal, more or less than that of dipole

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