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Home ‣ Electronics and Communication Engineering ‣ Microwave Communication See What Others Are Saying!
  • Question

  • In a travelling wave tube distributed interaction between an electron beam and a travelling wave takes place


  • Options
  • A. True
  • B. False

  • Correct Answer
  • True 

    Explanation
    In a klystron the resonant structure limits the bandwidth.

    A TWT is a broadband device. Its main components are electron gun (to produce the electron beam) and a structure supporting the slow electromagnetic wave.

    The velocity of wave propagation along the helix structure is less than velocity of light.

    The beam and wave travel along the structure at the same speed.

    Thus interaction occurs between beam and wave and the beam delivers energy to the RF wave.

    Therefore the signal gets strengthened and amplified output is delivered at the other end of tube.

    The main features of TWT are :

    1. Frequency range - 0.5 GHz to 90 GHz

    2. Power output - 5 mW at low frequencies(less than 20 GHz) 250 kW (continuous wave) at 3 GHz 10 MW (pulsed) at 3 GHz

    3. Efficiency - about 5 to 20%

    4. Noise - about 5 dB for low power TWT 25 dB for high power TWT

    TWT is used as RF amplifier in broadband microwave receivers, repeater amplifier in broad band communication systems, communication satellites etc.

    More questions

    • 1. Which of the following noise becomes of great importance at high frequencies?

    • Options
    • A. Transit-time noise
    • B. Shot noise
    • C. Flicker noise
    • D. Agitation noise
      • Discuss
    • 2. A current source inverter has simple commutation circuit.

    • Options
    • A. True
    • B. False
      • Discuss
    • 3. In the given figure the line voltage after a number of reflections will be

    • Options
    • A. 30 V
    • B. -30 V
    • C. 10 V
    • D. -10 V
      • Discuss
    • 4. When the core of a saturable reactor is saturated, the inductance is high.

    • Options
    • A. True
    • B. False
      • Discuss
    • 5. The output wave of a cycloconverter consists of a number of segments derived from the input wave.

    • Options
    • A. True
    • B. False
      • Discuss
    • 6. For the control system in the given figure, the value of K for critical damping is

    • Options
    • A. 1
    • B. 5.125
    • C. 6.831
    • D. 10
      • Discuss
    • 7. As the firing of a thyristor is delayed, the output voltage of a controlled rectifier decreases.

    • Options
    • A. True
    • B. False
      • Discuss
    • 8. The circuit of the given figure realizes the function

    • Options
    • A. Y = (A + B) C + DE
    • B. Y = A + B + C + D + E
    • C. AB + C +DE
    • D. AB + C(D + E)
      • Discuss
    • 9. The two modes of operation of three phase bridge inverters are known as

    • Options
    • A. 60° mode and 120° mode
    • B. 90° mode and 120° mode
    • C. 120° mode and 180° mode
    • D. 120° mode and 240° mode
      • Discuss
    • 10. A first order system will never be able to give a __________ response

      1. band stop
      2. band pass
      3. all pass
      Choose the correct option

    • Options
    • A. 1, 2, 3 true
    • B. 1 and 3 true, 2 false
    • C. 1, 2 are true 3 is false
    • D. 1, 2 are false, 3 is true
      • Discuss

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