Microwave Communication(Engineering > Electrical Engineering ) Questions and Answers

Question 1. Coupling into and out of a traveling-wave tube can be accompanied by a
  1.    Waveguide match
  2.    Cavity match
  3.    Direct coax-helix match
  4.    All of the above
Explanation:-
Answer: Option D. -> All of the above
Question 2. When it is desired that short-range targets be clearly seen on a pulsed-radar set, it is important that the receiver and display system have
  1.    A long time constant
  2.    Low-pass filters
  3.    The shortest possible time
  4.    The restricted high-frequency response
Explanation:-
Answer: Option C. -> The shortest possible time
Question 3. The aquadag coating on the inside of PPI tube is used
  1.    To focus the beam of primary electrons
  2.    To shield the electron beam from unidirectional magnetic
  3.    As a second anode and to prevent the build-up of secondary field
  4.    All of these
Explanation:-
Answer: Option C. -> As a second anode and to prevent the build-up of secondary field
Question 4. The antenna separations (in meters) required for optimum operation of a space diversity system can be calculated from:where R = effective earth radius (m) and L = path length (m)
  1.    S = 2λR/L
  2.    S = 3λR/L
  3.    S = λR/RL
  4.    S = λR/L
Explanation:-
Answer: Option B. -> S = 3λR/L
Question 5. What allow microwave to pass in only one direction?
  1.    RF emitter
  2.    Capacitor
  3.    Varactor-triac
  4.    Ferrite emitter
Explanation:-
Answer: Option D. -> Ferrite emitter
Question 6. If the instantaneous RF potentials on the two sides of a magnetron cavity are of opposite polarity, the operation is in the
  1.    π mode
  2.    π/2 mode
  3.    2π mode
  4.    π/4 mode
Explanation:-
Answer: Option A. -> π mode
Question 7. Oscillators of a klystron tube are maintained
  1.    By bunches of electrons passing the cavity grids
  2.    By plate-to-cathode feedback
  3.    By feedback between the accelerating grid and the repeller
  4.    By circulating bunches of electrons within the cavities.
Explanation:-
Answer: Option A. -> By bunches of electrons passing the cavity grids
Question 8. A PPI cathode-ray tube as used on a radar set
  1.    Is used to check the percentage of modulation
  2.    Indicates both the range and azimuth of a target
  3.    Indicates only the range of a target
  4.    Is used for receiver alignment
Explanation:-
Answer: Option B. -> Indicates both the range and azimuth of a target
Question 9. A high-power microwave pulse of the order of megawatts can be generated by a
  1.    Traveling-wave tube
  2.    Magnetron
  3.    Reflex klystron
  4.    Gunn diode
Explanation:-
Answer: Option B. -> Magnetron
Question 10. It is possible to increase the maximum range of a radar equipment by
  1.    Lowering the pulse frequency
  2.    Raising the peak power of the transmitter
  3.    Narrowing the beam width and increasing the pulse duration
  4.    All of these
Explanation:-
Answer: Option D. -> All of these
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