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Home Electronics and Communication Engineering Microwave Communication See What Others Are Saying!
  • Question
  • Consider the following statements

    1. Bunching of electrons occurs in two cavity klystron amplifier.
    2. Bunching of electrons occurs in multi cavity klystron amplifier.
    3. Bunching of electrons occurs in reflex cavity klystron amplifier.
    Which of the above statements are correct?


  • Options
  • A. 1, 2, and only
  • B. 1, 2 and 3 only
  • C. 1 and 3 only
  • D. 2 and 3 only

  • Correct Answer
  • 1, 2 and 3 only 

    Explanation
    A Klystron is a vacuum tube used for generation/amplification of microwaves.

    An electron beam is produced by oxide coated indirectly heated cathode and is focussed and accelerated by focussing electrode.

    This beam is transmitted through a glass tube. The input cavity where the beam enters the glass tube is called buncher.

    As electrons move ahead they see an accelerating field for half cycle and retarding field for the other half cycle.

    Therefore, some electrons are accelerated and some are retarded. This process is called velocity modulation.

    The velocity modulation causes bunching of electrons. This bunching effect converts velocity modulation into density modulation of beam.

    The input is fed at buncher cavity and output is taken at catcher cavity.

    In a two cavity klystron only buncher and catcher cavity are used. In multi cavity klystron one or more intermediate cavities are also used.

    The features of a multicavity klystron are :

    1. Frequency range - 0.25 GHz to 100 GHz

    2. Power output - 10 kW to several hundred kW

    3. Power gain - 60 dB (nominal value)

    4. Efficiency - about 40%.

    A multicavity klystron is used in UHF TV transmitters, Radar transmitter and satellite communication.


    More questions

    • 1. Consider the following statements about instrument landing system of aircraft

      1. It ensures correct landing under conditions of low visibility.
      2. It consists of runaway localizer, glide path equipment and marker beacons.
      3. It is basically a blind landing system.
      Which of above statements are correct?

    • Options
    • A. All
    • B. 1 and 2 only
    • C. 1 and 3 only
    • D. 2 only
    • Discuss
    • 2. The specified maximum junction temperature of thyristors is about

    • Options
    • A. 50°C
    • B. 80°C
    • C. 120°C
    • D. 200°C
    • Discuss
    • 3. In figure the saturation collector current is

    • Options
    • A.
    • B.
    • C.
    • D. none of the above
    • Discuss
    • 4. The source of which of the following noise is different from that of the remaining?

    • Options
    • A. Solar noise
    • B. Cosmic noise
    • C. Galactic noise
    • D. Atmospheric noise
    • Discuss
    • 5. If peak value of input voltage is Vm and firing angle is a, the average output voltage for single phase half wave and single phase full wave regulators are

    • Options
    • A.
    • B.
    • C.
    • D.
    • Discuss
    • 6. Radio broadcasting is a familiar example of

    • Options
    • A. space multiplexing
    • B. time multiplexing
    • C. frequency multiplexing
    • D. none of the above
    • Discuss
    • 7. A line has a phase constant of 29.8 rad/m. At 1000 MHz the wavelength is

    • Options
    • A. 29.8 m
    • B. 2.98 m
    • C. 2.1 m
    • D. 0.21 m
    • Discuss
    • 8. The class of insulation of impregnated paper is

    • Options
    • A. A
    • B. B
    • C. C
    • D. F
    • Discuss
    • 9. The quality of a space-link is measured in terms of the __________ ratio.

    • Options
    • A. C/N
    • B. S/N
    • C. G/T
    • D. EIRP
    • Discuss
    • 10. For a 50 ? resistor for 3 GHz application, the stray capacitance should be less than

    • Options
    • A. 1 ?F
    • B. 1 nF
    • C. 1 pF
    • D. 0.1 pF
    • Discuss


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