Communications Engineering Mastery Test 4: ECE Pre-Board

This is 100 items set of Practice Examination 4 in Communications Engineering (Electronics Systems and Technology) composed of previous Board Exams Questions. Read each questions and choices carefully! Choose the best answer. In the actual board, you have to answer 100 items in Communications Engineering within 5 hours. You have to get at least 70% to pass the subject. Communications Engineering is 30% of the total 100% Board Rating along with Mathematics (20%), General Engineering and Applied Sciences (20%) and Electronics Engineering (30%). Familiarize each and every questions to increase the chance of passing the ECE Board Examination.

Start the Test Yourself Exam 4

Choose the letter of the best answer in each questions.

1. ECE Board Exam April 1997

Extra-terrestrial noise is observable at frequencies from

• A. 0 to 20 KHz
• B. Above 2 GHz
• C. 8 to 1.43 GHz
• D. 5 to 8 GHz

2. ECE Board Exam April 1997

Band of light waves, that are too short to be seen by human eye.

• A. Visible
• B. Infrared
• C. Ultraviolet
• D. Amber

3. ECE Board Exam April 1997

Two wires that are bent 90 degrees apart.

• A. Hertz
• B. Dipole
• C. Log-periodic
• D. Rhombic

4. ECE Board Exam April 1997

The first symbol in the designation of radio emission under the ITU rules to

• A. Nature of signals modulating the main carrier
• B. Type of information to be transmitted
• C. Bandwidth
• D. Type of modulation of the main carrier

5. ECE Board Exam April 1997

Operating method in which the transmission is made alternately in each direction of a telecommunication channel

• A. Semi-duplex operation
• B. Duplex operation
• C. Half-duplex operation
• D. Simplex operation

6. ECE Board Exam April 1997

Production of radiation by a radio transmitting station

• A. Monitoring
• B. Emission
• C. Radiation
• D. Transmission

7. ECE Board Exam April 1997

The third symbol in the designation of radio emission under the ITU rules refers to

• A. Type of the modulation of the main carrier
• B. Bandwidth
• C. Nature of the signals modulating the main carrier
• D. Type of information to be transmitted

8. ECE Board Exam April 1997

A form of telecommunication for the transmission of transient images of fixed or moving objects.

• A. E-mail
• B. Television
• C. Radio
• D. Internet

9. ECE Board Exam April 1997

Radiation pattern of a discone.

• A. Unidirectional
• B. Bidirectional
• C. Omnidirectional
• D. Figure of eight

10. ECE Board Exam April 1997

Another SEG function that allows a person to be superimposed on another scene.

• A. Visual effect
• B. Wiper
• C. Chroma keying
• D. Special effect generation

11. ECE Board Exam April 1997

What signal-to-noise ratio is required for satisfactory telephone services?

• A. 50 dB
• B. 30 dB
• C. 40dB
• D. 20 dB

12. ECE Board Exam April 1997

The use of telecommunication for automatic indicating or recording measurement at the distance from the measuring instrument.

• A. Monitoring
• B. Tracking
• C. Telemetry
• D. Telecommand

13. ECE Board Exam April 1997

The standard deviation of the variation in the transmission loss of a circuit should not exceed

• A. 3 dB
• B. 1 dB
• C. 5 dB
• D. 0.5dB

14. ECE Board Exam April 1997

Noise caused by the thermal agitation of electrons in resistance.

• A. White noise
• B. Thermal noise
• C. Johnson’s noise
• D. All of these

15. ECE Board Exam April 1997

Unity gain antenna

• A. Isotropic
• B. Rhombic
• C. Half-wave dipole
• D. Dummy

16. ECE Board Exam April 1997

The series of periodically recurrent pulses is modulated in amplitude by the corresponding instantaneous samples.

• A. PFM
• B. PWM
• C. PDM
• D. PAM

17. ECE Board Exam April 1997

This type of transmission permits communication in the frequency range from 30 to 60 MHz and over distances from about 1000 to 2000 km.

• A. Troposcatter
• B. Ionospheric scatter
• C. Ducting
• D. Microwave

18. ECE Board Exam April 1997

A region in front of a paraboloid antenna.

• A. Transmission zone
• B. Fresnel
• C. Fraunhofer
• D. All of these

19. ECE Board Exam April 1997

Designates the sensation of low or high in the sense of the base and treble.

• A. Frequency
• B. Intensity
• C. Pitch
• D. SPL

20. ECE Board Exam April 1997

A good example of a pilot tone system used in commercial frequency modulation stations.

• A. FDM
• B. Time division
• C. Stereo multiplexing
• D. Frequency modulation

21. ECE Board Exam April 1997

Emission on a frequency or frequencies immediately outside the necessary bandwidth which result from the modulation process except spurious emission.

• A. Radiation
• B. Noise
• C. Out of the band
• D. Interference

22. ECE Board Exam April 1997

A helical antenna is used for satellite tracking because of ______.

• A. Broad bandwidth
• B. Good front-to-back
• C. Maneuverability
• D. Circular polarization

23. ECE Board Exam April 1997

Background noise is the same as the following except

• A. Impulse noise
• B. White noise
• C. Thermal noise
• D. Gaussian noise

24. ECE Board Exam April 1997

Electronic equipment used to measure standing wave ration.

• A. Reflectometer
• B. Wavemeter
• C. Altimeter
• D. Multimeter

25. ECE Board Exam April 1997

A single sideband emission in which the degree of carrier suppression enables the carrier to be reconstituted and to be used for demodulation.

• A. Reduce carrier single sideband emission
• B. Half carrier single sideband emission
• C. Full carrier single sideband emission
• D. Standard single sideband emission

26. ECE Board Exam April 1997

Station in the mobile service not intended to be used while in motion.

• A. Coast station
• B. Fixed station
• C. Base station
• D. Land station

27. ECE Board Exam April 1997

The electric field lines in a plane perpendicular to the earth’s surface.

• A. Elliptical polarization
• B. Circular polarization
• C. Horizontal polarization
• D. Vertical polarization

28. ECE Board Exam April 1997

Known to be the first satellite capable to receive and transmit simultaneously.

• A. Score
• B. Syncom I
• C. Telstar 1
• D. Echo1

29. ECE Board Exam April 1997

A digital carrier facility used to transmit a DSI-formatted signal at 1.544. Mbps.

• A. T2
• B. T1
• C. T4
• D. T3

30. ECE Board Exam April 1997

12 voice channels are sampled at 8000 sampling rate and encoded into 8 bit PCM word. Determine the rate of the data stream.

• a. 354 kbps
• b. 750 kbps
• c. 768 kbps
• d. 640 kbps

31. ECE Board Exam April 1997

The most common device used as a light detector in fiber optic communications system.

• A. LED
• B. Darlington phototransistor
• C. APDs
• D. PIN diode

32. ECE Board Exam April 1997

Two resistors, 20kΩ, and 50kΩ are at ambient temperature. Calculate for a bandwidth equal to 100kHz, the thermal noise voltage for the two resistors connected in parallel.

• A. 0.4782µV
• B. 4278 µV
• C. 4.78 µV
• D. 47.8 µV

33. ECE Board Exam April 1997

Calculate the energy of the photon of infrared light energy at 1.55µm

• A. 1.28 x 10^-19 J
• B. 1.6  x 10^-19 J
• C. 1.22 x 10^-16 J
• D. 1.9 x 10^-14 J

34. ECE Board Exam April 1997

If a fiber optic system has a rise time of 38.55 ns, the source rise time is 12 ns and the detector rise time is 12 ns, what is the cable rise time?

• A. 34.61 ns
• B. 14.55 ns
• C. 52.55 ns
• D. 26.25 ns

35. ECE Board Exam April 1997

Nominal voice channel

• A. 20 to 20 KHz
• B. 16 to 16 KHz
• C. 3 to 3 KHz
• D. 4 KHz

36. ECE Board Exam April 1997

Two or more antennas separated by 9 wavelengths are used.

• A. Hybrid diversity
• B. Space diversity
• C. Polarized diversity
• D. Frequency diversity

37. ECE Board Exam April 1997

Nif stands for

• A. Narrow intermediate frequency
• B. Noise interference figure
• C. Noise improvement factor
• D. Non-intrinsic figure

38. ECE Board Exam April 1997

Any small element of space in the path of a wave may be considered as a source of secondary wavelet.

• A. De Morgan’s Principle
• B. Faraday’s Law
• C. Huygen’s Principle
• D. Fresnel’s Law of optics

39. ECE Board Exam April 1997

Modulation in which the modulated wave is always present.

• A. Carrier modulation
• B. Front-end
• C. Continuous modulation
• D. Log-periodic modulation

40. ECE Board Exam April 1997

Atmospheric noise is less at severe frequencies above

• A. Audio level
• B. 30 MHz
• C. 10 GHz
• D. 1 GHz

41. ECE Board Exam April 1997

At height about 180 km above the earth exist only during daylight.

• A. F2 layer
• B. D layer
• C. E layer
• D. F1 layer

42. ECE Board Exam April 1997

Radiation characteristics of a dipole

• A. Figure of eight
• B. Omnidirectional
• C. Bidirectional
• D. Unidirectional

43. ECE Board Exam April 1997

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

44. ECE Board Exam April 1997

An electromagnetic wave is ________ polarized when the electric field lies wholly in one plane containing the direction of propagation.

• A. Horizontally
• B. Linearly
• C. Circularly
• D. Vertically

45. ECE Board Exam April 1997

A device that reduces the intensity of light in fiber optics communication systems.

• A. Reducer
• B. Quality factor
• C. Optical attenuator
• D. Compressor

46. ECE Board Exam April 1997

Propagation mode of microwave in a waveguide is known as _______.

• A. TM
• B. TE
• C. SW
• D. TEM

47. ECE Board Exam April 1997

The width of the frequency band which is just sufficient to ensure the transmission of information at the rate and with the quality required under a specified condition and class of emission.

• A. Occupied bandwidth
• B. Reference frequency
• C. Necessary bandwidth
• D. Frequency tolerance bandwidth

48. ECE Board Exam April 1997

A convenient method of determining antenna impedance.

• A. Stub matching
• B. Reactance circle
• C. Smith chart
• D. Trial and error

49. ECE Board Exam April 1997

Which of the following fall under the high frequency band of the radio spectrum?

• A. 8.2345 MHz
• B. 150.50 MHz
• C. 2.4555 MHz
• D. 35.535 MHz

50. ECE Board Exam April 1997

The electric field lies in a plane parallel to the earth’s surface.

• A. Elliptical polarization
• B. Horizontal polarization
• C. Vertical polarization
• D. Circular polarization

51. ECE Board Exam April 1997

The use of telecommunication for the transmission of signals to initiate, modify or terminate functions of equipment at a distance.

• A. Tracking
• B. Telemetry
• C. Telecommand
• D. Space telemetry

52. ECE Board Exam April 1997

The product of the power supplied to the antenna and its gain relative to a half-wave dipole in a given direction.

• A. Peak envelope power
• B. ERP
• C. Rated power
• D. Carrier power’

53. ECE Board Exam April 1997

The Ku-band in the satellite service

• A. 14/11 GHz
• B. 30/17 GHz
• C. 8/7 GHz
• D. 6/4 GHz

54. ECE Board Exam April 1997

The sinusoidal carrier is pulsed so that one of the binary states is represented by a carrier while the other is represented by its absence.

• A. FSK
• B. ASK
• C. PSK
• D. QAM

55. ECE Board Exam April 1997

Width measured in degrees of a major lobes between end of the love at which the relative power is one half (-3dB) its value from the peak of the lobe.

• A. Bandwidth
• B. Wavelength
• C. Radiation
• D. Beamwidth

56. ECE Board Exam April 1997

The most common unit of noise measurement in white noise voltage testing.

• A. NPR
• B. dBm
• C. dBW
• D. dBrn

57. ECE Board Exam April 1997

Any governmental office responsible in discharging the obligations undertaken in the convention of the ITU and the regulation.

• A. Administration
• B. The union
• C. Country
• D. Telecommunications office

58. ECE Board Exam April 1997

A large speaker having a large diameter (15 cm and above)

• A. Coaxial speaker
• B. Woofer
• C. Tweeter
• D. Trixial speaker

59. ECE Board Exam April 1997

Coaxial lines are used on those systems operating _______.

• A. Below 2 GHz
• B. At 300 MHz
• C. Above 10KHz
• D. Above 10GHz

60. ECE Board Exam April 1997

Determine the dynamic range for a 10 bit sign magnitude code.

• A. 1023
• B. 425
• C. 511
• D. 756

61. ECE Board Exam April 1997

A coherent binary phase shift keyed BPSK transmitter operates at a bit rate of 20 Mbps with a carrier to noise ratio C/N of 8.8dB. Find E_b/N_o.

• A. 73 dB
• B. 62.4 dB
• C. 81.8 dB
• D. 8.8 dB

62. ECE Board Exam April 1997

Receives and collects satellite signals form a broadcast satellite.

• A. LNB
• B. Yagi-Uda array
• C. Satellite receiver
• D. Satellite disk

63. ECE Board Exam April 1997

What is the effect in over modulated amplitude modulated radio broadcasting transmission?

• A. Interference to adjacent channel
• B. Higher fidelity
• C. Increase noise
• D. Higher audio signal

64. ECE Board Exam April 1997

Average power of a radio transmitter supplied to the antenna transmission line by a transmitter during one radio frequency cycle taken under the condition of no modulation.

• A. Peak envelop power
• B. Rated power
• C. Carrier power
• D. Mean power

65. ECE Board Exam April 1997

A method of expressing the amplitude of complex non-periodic signals such as speech.

• A. Frequency
• B. Wavelength
• C. Volume
• D. Pitch

66. ECE Board Exam April 1997

A government regulation in telecommunication which provide policy to improve the provision of local exchange carrier service.

• A. E.O. 109
• B. Act 3846
• C. E.O. 59
• D. E.O. 546

67. ECE Board Exam April 1997

Radio communication operation service between mobile and land stations or between mobile stations.

• A. Land mobile satellite service
• B. Maritime mobile service
• C. Mobile service
• D. Land mobile

68. ECE Board Exam April 1997

The smaller the f rating, the _____ light that lens can take in.

• A. More
• B. Intense
• C. Less
• D. Same

69. ECE Board Exam April 1997

A radio communications service use in radio regulation between specified fixed points provided primarily for the safety of air navigation and for the regular efficient and economical air transport.

• A. Space operation service
• B. Space service
• C. Aeronautical mobile service
• D. Aeronautical fixed service

70. ECE Board Exam April 1997

Harmonic suppressor connected to an antenna.

• A. High pass filter
• B. Low pass filter
• C. Tank circuit
• D. M-derived filter

71. ECE Board Exam April 1997

The tendency of the sound energy to spread.

• A. Rarefaction
• B. Reflection
• C. Refraction
• D. Diffraction

72. ECE Board Exam April 1997

An earth satellite whose period of revolution is equal to the period of rotation of the earth about its axis.

• A. Geosynchronous
• B. Steerable
• C. Passive
• D. Active

73. ECE Board Exam April 1997

A figure of merit used to measure the performance of a radiation detector.

• A. Noise equivalent power
• B. Ripple factor
• C. Safe factor
• D. Quality factor

74. ECE Board Exam April 1997

Radio wave concentration in the direction of the signal emitted by a directional antenna.

• A. Back lobe radiation
• B. Side lobe radiation
• C. Major lobe radiation
• D. Transmitted signal

75. ECE Board Exam April 1997

What is the channel bandwidth of a standard analogue telephone system?

• A. 300 - 500 Hz
• B. 1200 kHz
• C. 100 - 300 Hz
• D. 300 - 3400 Hz

76. ECE Board Exam April 1997

A satellite receives an uplink frequency of _______ MHz from a ground station of 3700 MHz.

• A. 8150 MHz
• B. 1475 MHz
• C. 2225 MHz
• D. 5925 MHz

77. ECE Board Exam April 1997

The outer conductor of a coaxial transmission line is always grounded at the

• A. Input only
• B. Input and output
• C. Output only
• D. Point of high SWR

78. ECE Board Exam April 1997

Sound intensity is given as

• A. df/dP
• B. dE/dp
• C. dA/dP
• D. dP/dA

79. ECE Board Exam April 1997

The lowest frequency produced by an instrument.

• A. Harmonic
• B. Fundamental
• C. Midrange
• D. 0 Hz

80. ECE Board Exam April 1997

The reflector and director of an antenna array are considered as

• A. Parasitic elements
• B. Transcendental elements
• C. Feed-points
• D. Driven elements

81. ECE Board Exam April 1997

The core of the optical fiber has ______.

• A. A medium index of refraction
• B. A lower index of refraction than the cladding
• C. A lower index of refraction than air
• D. A higher index of refraction than the cladding

82. ECE Board Exam April 1997

What makes an antenna physically long but electrically short?

• A. Top loading
• B. Adding C in series
• C. Adding L in series
• D. All of these

83. ECE Board Exam April 1997

An AM transmitter is rated 100W at 100% modulation. How much power required for the carrier?

• A. 33.33 W
• B. 66.66 W
• C. 83.33 W
• D. 100 W

84. ECE Board Exam April 1997

Used for time division multiplexing.

• A. Frequency modulation
• B. Pulsed modulation
• C. SSB
• D. Amplitude modulation

85. ECE Board Exam April 1997

A means of beyond the line-of-sight propagation of microwave signal.

• A. Space wave
• B. Microwave link
• C. Troposcatter
• D. Point-to-point

86. ECE Board Exam April 1997

Which of the following refers to the smallest beam of satellite antenna’s radiation pattern?

• A. Hemispheric beam
• B. Spot beam
• C. Zone beam
• D. Global beam

87. ECE Board Exam April 1997

Theoretical gain of a hertzian dipole

• A. 0 dB
• B. 1.76 dB
• C. 3 dB
• D. 2.15 dB

88. ECE Board Exam April 1997

Satellite system or part of a satellite system, consisting of only one satellite and the operating earth station.

• A. Satellite system
• B. Satellite network
• C. Space system
• D. Multi-satellite link

89. ECE Board Exam April 1997

The difference between the original and reconstructed signal gives rise to

• A. S factor
• B. Quantizing noise
• C. S/N
• D. Fade margin

90. ECE Board Exam April 1997

An area in the memory used for temporary storage of information, on “Last in First out” basis.

• A. Core
• B. Register
• C. Flag
• D. Stack

91. ECE Board Exam April 1997

Refers to a land station in a maritime mobile service

• A. Coast station
• B. Ship earth station
• C. Coast earth station
• D. Maritime station

92. ECE Board Exam April 1997

Modulation in which no signal is present between pulses

• A. Pulse modulation
• B. QAM
• C. PSK
• D. FSK

93. ECE Board Exam April 1997

In the designation of bandwidth and emission, what letter in the first symbol represents a double-sideband type of modulation?

• A. A
• B. B
• C. C
• D. H

94. ECE Board Exam April 1997

Loss due to the diffraction of light when it strikes on the irregularities formed during the manufacturing process of the fiber optics.

• A. Absorption loss
• B. Attenuation
• C. Bending loss
• D. Rayleigh scattering loss

95. ECE Board Exam April 1997

What is the unit of electric field strength?

• A. Watt/meter
• B. Ohms/meter
• C. Ampere/meter
• D. Watt/meter²
• E. No answer

96. ECE Board Exam April 1997

Refers to the first generation of local loop system in telecommunication technology.

• A. GSM
• B. DECT
• C. Analogue cellular
• D. TACS

97. ECE Board Exam April 1997

An area on the surface of the earth within which the bore sight of the steerable satellite beam intended to be pointed

• A. Effective boresight area
• B. Countour boresight area
• C. Coordination boresight are
• D. Equivalent boresight area

98. ECE Board Exam April 1997

For a sample rate of 40 kHz, determine the maximum analog input frequency

• A. 30 kHz
• B. 40 kHz
• C. 20 kHz
• D. 10 kHz

99. ECE Board Exam April 1997

An antenna that can only receive a television signal.

• A. Isotropic antenna
• B. TVRO
• C. Reference antenna
• D. Yagi antenna

100. ECE Board Exam April 1997

Halo is also called

• A. Flare
• B. Dark current
• C. Glitch
• D. Ghost

Complete List of Communications Engineering Exams: ECE Pre-Board

Series of Communications Engineering Exams: ECE Pre-Board

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Answers key in Communications Engineering Exam 4: ECE Pre-Board

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