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ECE :: Radio Receivers

  1. Noise limiter is provided on AM receivers to

  2. A.
    reduce interfering noise due to ignition system
    B.
    reduce noise due to electrical storms
    C.
    reduce interference due to electrical machinery
    D.
    all of the above

  3. A low ratio of the A.C. load impedance of a diode detector results in

  4. A.
    diagonal clipping
    B.
    poor AGC operation
    C.
    poor AF response
    D.
    negative peak clipping

  5. A trimmer is basically a

  6. A.
    insulator
    B.
    inductor
    C.
    capacitor
    D.
    variable resistor

  7. In a radio receiver

  8. A.
    all stages contribute equally to noise
    B.
    RF stage has no effect on S/N ratio
    C.
    mixer stage contributes most of the noise generated

  9. Which curve represents the fidelity curve of a standard receiver?

  10. A.
    Curve A
    B.
    Curve B
    C.
    Curve C
    D.
    Curve D

  11. The sensitivity of a superheterodyne receiver is determined by

  12. A.
    the gain IF amplifier
    B.
    the gain of RF amplifier
    C.
    the noise figure
    D.
    all of the above

  13. In a radio receiver

  14. A.
    the local oscillator frequency is made higher than the incoming signal frequency
    B.
    the local oscillator frequency is made lower than the incoming signal frequency
    C.
    the local oscillator frequency is made equal to the incoming signal frequency

  15. In radio receiver, the maximum contribution to noise is from

  16. A.
    mixer stage
    B.
    power supply
    C.
    power amplifier
    D.
    equally from above three

  17. Power spectral density of white noise

  18. A.
    is constant with frequency
    B.
    increases with frequency
    C.
    decreases with frequency
    D.
    none

  19. In a FM waveform, the side bands are spaced at intervals equal to

  20. A.
    four times the modulating frequency
    B.
    twice the modulating frequency
    C.
    half the modulating frequency
    D.
    modulating frequency