1. Referred to as a ferrite device that can be used in lieu of a duplexer to isolate a microwave transmitter and receiver when both are connected to the same antenna.
- Isolator
- Circulator
- Coupler
- Diode
2. What is the principal mode of a rectangular waveguide?
a. TEM
b. TE11
c. TE10
d. TM11
3. What microwave device combines the advantages of the klystron and the Traveling Wave Tube?
a. Stripline
b. Microstrip
c. Cfa
d. Twystron
4. A microwave tube that uses a slow-wave structure as an input section that is isolated from another slow-wave section at its output.
a. Klystron
b. Magnetron
c. Twystron
d. TWT
5. A waveguide acts as a
a. LPF
b. HPF
c. BPF
d. Resonator
6. Which of the following is a microwave frequency?
a. 1.7 MHz
b. 750 MHz
c. 0.98 GHz
d. 22 GHz
7. Which of the following permits a microwave signal to travel in one direction with virtually no loss but severely attenuates any signal attempting to travel in the reverse direction?
a. Isolator
b. Wave trap
c. Tunnel diode
d. Circulator
8. A waveguide has a cut-off frequency of 17 GHz. Which of the following signals will not pass thru the waveguide?
a. 15 GHz
b. 18 Ghz
c. 22 GHz
d. 255 GHz
9. When the electric field is perpendicular to the direction of propagation, the mode is said to be
a. Vertically polarized
b. Horizontally polarized
c. Transverse electric
d. Transverse magnetic
10. Which of the following is not a microwave tube?
a. TWT
b. CRT
c. Klystron
d. Magnetron
11. A measure of the reliability expressed as the average number of hours between successive failures.
a. MTBF
b. MTTR
c. Downtime
d. Outage time
12. A microwave band of 18 to 27 GHz is considered as the ______ band.
a. C
b. X
c. Q
d. K
13. The radius in the circular zone is in the first fresnel zone when the reflected path is ______ longer than the direct path.
a. Half wavelength
b. Wavelength
c. Quarter wavelength
d. 2wavelengths
14. The microwave path wherein the microwave beam just barely touches the obstruction.
a. LOS
b. Grazing
c. Obstructed path
d. Direct path
15. A fade margin of 28 dB has a reliability of
a. 99%
b. 99.9%
c. 99.99%
d. 99.999%
16. The velocity of a resultant wave as it travels through the waveguide.
a. Speed of light
b. Group velocity
c. Phase velocity
d. Incident velocity
17. The smallest free space wavelength that is just unable to propagate in the waveguide under given conditions.
a. Guide
b. Phase
c. Cut-off
d. Group
18. Indicate which of the following cannot be followed by the word "waveguide".
a. Elliptical
b. Flexible
c. Coaxial
d. Ridge
19. Which of the following waveguide tuning components is not easily adjustable?
a. Screw
b. Stub
c. Iris
d. Plunger
20. What microwave component can sample part of the power traveling thru the waveguide?
a. Directional coupler
b. Magic tee
c. Circulator
d. Isolator
21. A rectangular waveguide is 5.1 cm by 2.4 cm. The cut-off frequency for the dominant mode is
a. 2.94 GHz
b. 6.25 GHz
c. 664 MHz
d. 57.7 GHz
22. If the MTBF of a communications circuit is 20,000 hours and its MTTR is 5 hours, what is its unavailability?
a. 0.00025
b. 99.975%
c. 0.25%
d. 0.975%
23. What would be the ERP, in watts, if the transmitter output is 30 dBm and the waveguide loss is 20 dB and the antenna connected to it has a power gain of 60 dB?
a. 10000 watts
b. 1000 watts
c. 100 watts
d. 10 watts
24. A waveguide section used to couple a circular to a rectangular waveguide.
a. Taper
b. Twist
c. Bend
d. Tee
25. A waveguide section used to change the signal polarization
a. Taper
b. Twist
c. Bend
d. Tee
26. A waveguide section used to combine two or more signals
a. Taper
b. Twist
c. Bend
d. Tee
27. A signal propagated in a waveguide has a full wave of electric field intensity change between two further walls and no component of the electric field in the direction of propagation. The mode is
a. TE11
b. TE10
c. TM22
d. TE20
28. A microwave transmission line constructed of a center conductor suspended between parallel conductive ground planes is called
a. Microstrip
b. Coax
c. Stripline
d. Waveguide
29. The principal characteristic of tunnel diodes
a. Negative resistance region
b. High forward current rating
c. Very high piv
d. High forward resistance
30. A metal wrapped around the parabolic antenna aperture to eliminate sidelobes interferin nearby stations.
a. Radome
b. Shield
c. Shroud
d. Bass drum
31. The region within the influence of the induction field of an antenna.
a. Far field
b. Near field
c. Radiation field
d. Radiation pattern
32. Which of the following is unlikely to be used as a pulse device?
a. TWT
b. CFA
c. BWO
d. Multicavity Klystron
33. The wavelength of microwaves at 100 GHz?
a. 3 cm
b. 0.3 cm
c. 0.03 cm
d. 0.3 m
34. The k factor under normal atmospheric conditions in a microwave radio data profile calculation is
a. 2/3
b. 0
c. 4/3
d. 1
35. To install an antenna with an LOS transmission at a distance of 75 miles, determine the height of a receiving antenna if the transmitting antenna is 250 ft.
a. 1385 ft
b. 600 ft
c. 400 ft
d. 255 ft
36. Determine the gain of a 6 ft parabolic dish operating at 1800 MHz.
a. 30 dB
b. 11.2 dB
c. 15.5 dB
d. 28.17 dB
37. What is the free space loss, in dB, between two microwave antennas 38 km apart operating at 7 GHz?
a. 145.6 dB
b. 138.5 dB
c. 135.5 dB
d. 140.89 dB
38. How many receiving antenna(s) are used with frequency diversity?
a. 1
b. 2
c. 3
d. 4
39. A type of diversity reception, where the output of the transmitter is fed to two or more antennas that are physically separated by an appreciable number of wavelengths.
a. Frequency
b. Space
c. Angle
d. Polarization
40. Which of the following is used as a high power microwave oscillator?
a. Thyratron
b. Magnetron
c. Klystron
d. Twystron
41. A microwave communications system space loss calculation formula
a. 94.2 + 20 log F + 20 log D
b. 92.4 + 20 log F + 20 log D
c. 94.2 + 10 log F + 20 log D
d. 92.3 + 10 log F + 20 log D
42. Which of the following frequency bands fall under the microwave band?
a. UHF and SHF
b. SHF and EHF
c. UHF, SHF and EHF
d. VLF, LF and MF
43. Find the cut-off frequency for a waveguide in the TE21 mode if the dimensions of the guide are 3 by 1.5 cm with wall thickness of 0.08 cm.
a. 14.14 GHz
b. 5 GHz
c. 5.28 GHz
d. 15.39 GHz
44. The progressive decrease of signal strength with increasing distance
a. Radiation
b. Attenuation
c. Modulation
d. Propagation
45. A magnetic field is introduced into the waveguide by a
a. probe
b. dipole
c. stripline
d. capacitor
46. Varactor and step recovery diodes are widely used in what type of circuit?
a. Amplifier
b. Oscillator
c. Frequency multiplier
d. Mixer
47. The optimum clearance from an obstacle in a microwave system is accepted as ________ of the first fresnel zone radius.
a. 0.6
b. 0.5
c. 0.9
d. 1.5
48. A range of microwave frequencies more easily passed by the atmosphere than the others
a. Window
b. Critical frequency
c. Gyro frequency
d. Resonant
49. When microwave signals follow the curvature of the earth, this is known as
a. Faraday effect
b. Ducting
c. Troposcatter
d. Ionospheric reflection
50. A waveguide mode in which there is no component of electric field in the direction of propagation given in the British European standards
a. H mode
b. E mode
c. TE mode
d. TM mode
51. The subscript which indicates the number of half wavelengths along the waveguide height
a. m
b. n
c. a
d. b
52. Which of the following microwave tubes uses the principle of velocity modulation?
a. TWT
b. CFA
c. Magnetron
d. klystron
53. An X band radar operates in which frequency band?
a. 1 - 2 GHz
b. 2 - 4 GHz
c. 4 - 8 GHz
d. 8 - 12 GHz
54. Calculate the cut-off wavelength, the guide wavelength and the characteristic impedance of a circular waveguide whose internal diameter is 4 cm for a 10 GHz signal propagated in it in the dominant mode. (kr = 1.84)
a. 6.83 cm, 3 cm, 420 ohms
b. 3 cm, 6.83 cm, 420 ohms
c. 6.83 cm, 3.34 cm, 420 ohms
d. 6.83 cm, 3.34 cm, 338 ohms
55. A wave is propagated in a parallel plane waveguide. The frequency is 6 GHz and the plane separation is 3 cm. The cut-off wavelength for the dominant mode, the group and phase velocities are
a. 5 cm, 166 Mm/sec, 543 Mm/sec
b. 6 cm, 166 Mm/sec, 543 Mm/sec
c. 6 cm, 543 Mm/sec, 166 Mm/sec
d. 5 cm, 543 Mm/sec, 166 Mm/sec
56. The following are negative resistance amplifiers except
a. Tunnel
b. Gunn
c. IMPATT
d. PIN diode
57. A cross between the TWT and the magnetron in its operation
a. CFA
b. BWO
c. EIA
d. Twystron
58. Diodes designed to store energy in their capacitance during forward bias and generates harmonics in the reverse bias
a. Step recovery
b. Gunn
c. APD
d. IMPATT
59. Topographical maps are maps used for microwave communications systems design because _________ are shown, thereby elevations are known.
a. Latitudes
b. Longitudes
c. Contour lines
d. Scales
60. Surface Acoustic Waves propagate in
a. GaAs
b. Indium Phosphide
c. Stripline
d. Quartz crystal
61. What do you call the process of speeding up and slowing down the beam of electrons in the vacuum tube?
a. Velocity modulation
b. Logitudinal velocity
c. Gyrofrequency
d. Group frequency
62. What is the name of the microwave transmission line that is used with printed circuits?
a. Ferrite loop
b. Coax
c. Waveguide
d. Microstrip
63. The output of a LASER is monochromatic; this means that it is
a. Infrared
b. Narrow beam
c. Polarized
d. Single frequency
64. The attenuator is used in the TWT to
a. Help bunching
b. Prevent oscillation
c. Prevent saturation
d. Increase gain
65. The angle between electric and magnetic fields in a waveguide is
a. 90 degrees
b. 0 degrees
c. 180 degrees
d. 360 degrees
66. Materials generally preferred for waveguides are
a. Brass and aluminum
b. Cast iron and steel
c. Non-metallic solids
d. High carbon steel and vanadian steel
67. Waveguide feeders are pressurized to
a. Reduce loss
b. Reduce noise
c. Detect faults
d. Prevent ingress of moisture
68. In order to reduce cross-sectional dimension, which of the following waveguides is preferred?
a. Flexible
b. Rectangular
c. Circular
d. Ridged
69. A low noise, low power, narrow band microwave amplifier utilizing a varactor to achieve gain
a. Parametric amplifier
b. LNA
c. SAW
d. CFA
70. Which of the following uses buncher and catcher cavities?
a. magnetron
b. klystron
c. TWT
d. Stripline
1 comments:
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