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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. The number of spectral component when two cosine waves are multiplied of different frequency

    2. A.
    1
    B.
    2
    C.
    8
    D.
    4

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  2. Radiation resistance of an antenna is a

    3. A.
    dc resistance
    B.
    ac resistance
    C.
    either (a) or (b)
    D.
    none of the above

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  3. A 1 MHz sinusoidal carrier is amplitude modulated by a symmetrical square wave of period 100 μ sec. Which of the following frequencies will not be in the modulated signal?

    4. A.
    990 kHz
    B.
    1010 kHz
    C.
    1020 kHz
    D.
    1030 kHz

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  4. The input to a coherent detector is DSB - SC signal plus noise. The noise at the detector output is

    5. A.
    in phase component
    B.
    quadrature component
    C.
    zero
    D.
    the envelope

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  5. All of the output pulses are at full transmitter power for a strong signal in all of the following except

    6. A.
    PWM
    B.
    PAM
    C.
    PFM
    D.
    PCM

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  6. A pure tone at 1000 Hz has a dB level of 40 dB. If the required dB level is 100, the number of such tones is

    7. A.
    2.5
    B.
    60
    C.
    104
    D.
    106

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  7. The spectrum of the white noise and an impulse function is similar in following aspects

    8. A.
    both have similar magnitude spectrum
    B.
    both have similar magnitude and Phase spectrum
    C.
    no relation
    D.
    similar phase spectrum

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  8. In a telephone system, the grade of service means

    9. A.
    the quality of sound reception at the receiver telephone
    B.
    the probability that a called for connection is established
    C.
    the type of wires cables used for the system
    D.
    none of the above

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  9. A longwave AM broadcast transmitter needs

    10. A.
    very small carrier power
    B.
    very large carrier power
    C.
    small carrier power
    D.
    large carrier power

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  10. AGC voltage is applied to the stages which are

    11. A.
    before the detector stage
    B.
    after the detector stage
    C.
    either before or after the detector stage
    D.
    none of the above

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