logo

CuriousTab

CuriousTab

Discussion

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

  • Assertion (A): A backward wave oscillator can be used as a sweep generator.

    Reason (R): The frequency of oscillation of a backward wave oscillator can be changed by varying the voltage which controls the beam velocity.


  • Options
  • A. Both A and R are correct and R is correct explanation of A
  • B. Both A and R are correct but R is not correct explanation of A
  • C. A is correct but R is wrong
  • D. A is wrong but R is correct

  • Correct Answer
  • Both A and R are correct and R is correct explanation of A 

    Explanation
    It is somewhat similar to TWT and can deliver microwave power over a wide frequency band.

    It has an electron gun and a helix structure. However the interaction between electron beam and RF wave is different than in TWT.

    The growing RF wave travels in opposite direction to the electron beam.

    The frequency of wave can be changed by changing the voltage which controls the beam velocity.

    Moreover the amplitude of oscillations can be decreased continuously to zero by changing the beam current.

    It features are:

    1. Frequency range - 1 GHz to 1000 GHz.

    2. Power output - 10 mV to 150 mW (continuous wave) 250kW (pulsed).

    It is used as signal source in transmitters and instruments.

    More questions

    • 1. A material has N spins per m3. If Np are the dipoles per m3 parallel to field and Na are the dipoles per m3 anti-parallel to field, the magnetisation is

    • Options
    • A.
    • B.
    • C.
    • D.
      • Discuss
    • 2. The types of carriers in a semiconductor are

    • Options
    • A. 1
    • B. 2
    • C. 3
    • D. 4
      • Discuss
    • 3. In the given figure power meters at A and B indicate 1 mW and 110 ?W respectively. VSWR of line is

    • Options
    • A. 1.5
    • B. 2
    • C. 2.5
    • D. 3
      • Discuss
    • 4. In an ordinary thyristor

    • Options
    • A. turn on and turn off times are equal
    • B. turn on time is more than turn off time
    • C. turn off time is more than turn on time
    • D. turn on time may be equal, less than or more than turn off time
      • Discuss
    • 5. Consider the system with and where p and q are arbitrary real numbers. Which of the following statements about the controllability of the system is true?

    • Options
    • A. The system is completely state controllable for any non zero values p and q
    • B. Only p = 0 and q = 0 result in controllability
    • C. The system is uncontrollable for all values of p and q
    • D. We cannot conclude about controllability from the given data
      • Discuss
    • 6. Which of the following is invalid in Basic?

    • Options
    • A. A ** B + - C
    • B. A ** B - C
    • C. A * B - C
    • D. A * B - C ** D
      • Discuss
    • 7. Ferrite have

    • Options
    • A. low copper loss
    • B. low eddy current loss
    • C. low resistivity
    • D. higher specific gravity compared to iron
      • Discuss
    • 8. The inverse of given Laplace transform is


    • Options
    • A. sin t
    • B. cos t
    • C. et
    • D. e2t
      • Discuss
    • 9. If and A + B is

    • Options
    • A.
    • B.
    • C.
    • D.
      • Discuss
    • 10. JCOKE = 3
      JCOKE = JCOKE + 1
      GO TO (5, 8, 9, 11, 15, 16 18, 20) JCOKE.

      After the execution of above statement, the control is transferred to statement number

    • Options
    • A. 8
    • B. 11
    • C. 16
    • D. 20
      • Discuss

    Comments

    There are no comments.
Enter a new Comment




Aptitude

Engineering

Programming

Reasoning

Links

Copyright ©CuriousTab. All rights reserved.