Communications Engineering Exam 2: ECE Pre-Board

Pre-Board Examinations in Communications Engineering Module 2 composed of previous Board Exams Questions. Familiarize each and every questions.

This is 100 items set of Practice Examination 2 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 2

Choose the letter of the best answer in each questions.

1. ECE Board Exam November 1996

• A. HF
• B. UHF
• C. MF
• D. VHF

2. ECE Board Exam November 1996

A system that performs parallel-to-serial and serial-to-parallel conversion of data link.

• A. DCE
• B. DTE
• C. Modem
• D. PC

3. ECE Board Exam November 1996

The line control unit (LCU) operates on the data digital form.

• A. Data communications equipment (DCE)
• B. UART
• C. Modem
• D. Data terminal equipment (DTE)

4. ECE Board Exam November 1996

Quantization noise is caused by

• A. binary coding techniques
• B. serial transmission errors
• C. the synchronization between encoder and decoder
• D. the approximation of the quantized signal

5. ECE Board Exam November 1996

Speaker is a device that __________.

• A. convert current variations into sound waves
• B. none of these
• C. convert electrical energy to mechanical energy
• D. convert sound waves into current and voltage

6. ECE Board Exam November 1996

An object farther from a converging lens than its focal point always has an _______ image.

• A. virtual
• B. the same in size
• C. inverted
• D. smaller size

7. ECE Board Exam November 1996

The loss in signal power as light travels down a fiber is

• A. attenuation
• B. propagation
• C. absorption
• D. scattering

8. ECE Board Exam November 1996

Energy that has neither been radiated into space nor completely transmitted.

• A. Captured waves
• B. Incident waves
• C. Standing waves
• D. Modulated waves

9. ECE Board Exam November 1996

One of the reasons why FDM is being replaced by TDM is

• A. noise is amplified with voice when an FDM system is used
• B. it is difficult to place channels side by side
• C. there is more time than frequency
• D. Most available frequencies has been used

10. ECE Board Exam November 1996

Which determines the number of sideband components of FM?

• A. Modulation frequency
• B. Modulation index
• C. Carrier frequency
• D. All of these

11. ECE Board Exam November 1996

How would one squeeze more channels of communication into TDM frames of standard length?

• A. Shorten the time delay for each channel
• B. Raise the amplitude
• D. Remove the synchronizing pulses

12. ECE Board Exam November 1996

When one stations is designated as master and rest of the stations are considered slaves message handling is ________.

• A. polling
• B. WAN
• C. LAN
• D. OSI

13. ECE Board Exam November 1996

How many satellite orbital slots are requested by the Philippine government from ITU?

• A. 2
• B. 6
• C. 5
• D. 3

14. ECE Board Exam November 1996

The output of a balanced modulator is ____________.

• A. LSB and USB
• B. LSB
• C. USB
• D. Carrier

15. ECE Board Exam November 1996

RS-232, RS-449, RS-530, V, 24 and X.21 are examples of ____________.

• A. standards for interfaces between modems and transmission facilities
• B. standards for various types of transmission channels
• C. standards for interfaces between terminals and modems
• D. standards for end to end performance of data communications system

16. ECE Board Exam November 1996

A special service circuit connecting two private branch exchanges (PBX).

• A. Phantom line
• B. Private line
• C. Tie trunk
• D. Tandem trunk

17. ECE Board Exam November 1996

What is the baseband frequency of standard FDM basic supergroup?

• A. 312 to 552 kHz
• B. 300 to 600 kHz
• C. 60 to 2540 kHz
• D. 60 to 108 kHz

18. ECE Board Exam November 1996

What is the data rate of the ISDN Basic access B channel?

• A. 192 kbps
• B. 32 kbps
• C. 64 kbps
• D. 144 kbps

19. ECE Board Exam November 1996

Which tester is used to measure SWR?

• A. Spectrum analyzer
• B. Multimeter
• C. Reflectometer
• D. Oscilloscope

20. ECE Board Exam November 1996

What is the transmission rate of a GSM cellular system?

• A. 64 kbps
• B. 240 kbps
• C. 128 kbps
• D. 270 kbps

21. ECE Board Exam November 1996

A dipole antenna requires to be feed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11 kW. What is the gain in dB obtain by the use of the reflector ? ( Gain referred to this particular dipole)

• A. 4.24
• B. 1.81
• C. 4.75
• D. 2.6

22. ECE Board Exam November 1996

Pulse carrier at the ratio of 8000 pulse/sec is amplitude modulated by an analog signal this type of modulation is

• A. PAM
• C. DM
• D. PCM

23. ECE Board Exam November 1996

What is the applied power if a thermal RF wattmeter is connected to a transmitter through a variable attenuator? The wattmeter reads 84 mW when 15 dB of attenuation is used.

• A. 4.656 watts
• B. 2.656 watts
• C. 3.656 watts
• D. 2.856 watts

24. ECE Board Exam November 1996

Collects very weak signal from a broadcast satellite

• A. Satellite dish
• B. LNB
• C. Yagi-Uda antenna

25. ECE Board Exam November 1996

A seven-bit character can represent one of _________ possibilities.

• A. 14
• B. 64
• C. 128
• D. 7

26. ECE Board Exam November 1996

The maximum power suggested by KBP on 919-1312 AM broadcast station in Metro Manila is

• A. 10 kW
• B. 20 kW
• C. 15 kW
• D. 5 kW

27. ECE Board Exam November 1996

A loudspeaker cabinet has an internal volume of 5,184 in3 (84,950 cm3). It has a port area on the baffle of 50 in2 (322.58cm2) and a thickness of 0.70 in (18 mm). What is the Helmholtz resonance, in hertz, of this loudspeaker enclosure?

• A. 250 Hz
• B. 245 Hz
• C. 240 Hz
• D. 255 Hz

28. ECE Board Exam November 1996

When the clearance above the obstruction is equal to the radii of even Fresnel zone at the point of reflection the RSL

• A. remains the same
• B. is above threshold
• C. is decreased
• D. is increased

29. ECE Board Exam November 1996

Digital transmission provides a higher level of signal quality than analog transmission because

• A. repeaters regenerate digital pulses and remove distortion
• B. digital signals are easier to sample than analog signals
• C. digital signals are smaller than analog signals and cannot easily be distorted
• D. analog signals are continuous and not easily distorted.

30. ECE Board Exam November 1996

A _________ interconnects LAN having identical protocols at the physical and data link layers.

• A. All of these
• B. bridge
• C. router
• D. Gateway

31. ECE Board Exam November 1996

Both frequency and phase modulation utilize ________ modulation

• A. Phase
• B. AM and FM
• C. Digital
• D. Angle

32. ECE Board Exam November 1996

The different angles of entry of light into an optical fiber when the diameter of the core is many times the wavelength of the light transmitter is known as ________.

• A. refraction
• B. sensor
• C. mode
• D. emitter

33. ECE Board Exam November 1996

An invitation from the primary to a secondary to transmit a message.

• A. Retransmission
• B. Selection
• C. Reuse
• D. Polling

34. ECE Board Exam November 1996

An agency of the United Nations that formulates standards and recommend practices for all civil aviation

• A. ICAO
• B. CAA
• C. IATA
• D. ATO

35. ECE Board Exam November 1996

The transformer signal coding method for T1 carrier is

• A. Binary
• B. NRZ
• C. Manchester
• D. Bipolar

36. ECE Board Exam November 1996

When the value of k increases, the effective result is ______ of the equivalent curvatures.

• A. downward curvatures
• B. flattening
• C. bulging
• D. sharp curvature

37. ECE Board Exam November 1996

An electromagnetic wave consists of

• A. a magnetic field only
• B. both electric and magnetic fields
• C. an electric field only
• D. non-magnetic field only

38. ECE Board Exam November 1996

In a transmission line, if the maximum current to minimum current ratio is 2:1 what is the ratio of the maximum voltage to minimum voltage?

• A. 4:1
• B. 1:2
• C. 1:4
• D. 2:1

39. ECE Board Exam November 1996

Satellite signal transmitted from a satellite transponder to earth’s station.

• A. Vertically polarized
• D. RHCP

40. ECE Board Exam November 1996

Multiplexing scheme use by baseband transmission.

• A. FDM
• B. Space multiplexing
• C. TDM
• D. Statistical multiplexing

41. ECE Board Exam November 1996

Which stands for dB relative level?

• A. dBrn
• B. dBm
• C. dBr
• D. dBa

42. ECE Board Exam November 1996

What is the maximum color TV bandwidth?

• A. 1.6 MHz
• B. 0.5 MHz
• C. 1.0 MHz
• D. 1.3 MHz

43. ECE Board Exam November 1996

If Ns = 250, determine the earth radius k-factor.

• A. 1.98
• B. 1.23
• C. 1.33
• D. 1.29

44. ECE Board Exam November 1996

Digital modulation technique used in modems.

• B. PSK
• C. FSK
• D. All of these

45. ECE Board Exam November 1996

Which of the following is not a baseband signal modulation?

• A. RF carrier
• B. Video System
• C. Audio signal
• D. Binary coded pulses

46. ECE Board Exam November 1996

The standing wave ratio is equal to ________ if the load is properly matched with the transmission line.

• A. 1
• B. 50
• C. 10
• D. 2

47. ECE Board Exam November 1996

Noise from random acoustic or electric noise that has equal per cycle over a specified total frequency band.

• A. Thermal noise
• B. White noise
• C. Gaussian noise
• D. All of these

48. ECE Board Exam November 1996

When was the UHF channel (14-83) of television were added?

• A. 1852
• B. 1904
• C. 1947
• D. 1952

49. ECE Board Exam November 1996

Multiplexing in a time division multiplexer occurs based upon

• A. the position of a frame within the group of frames
• B. the positioning of data within a frame
• C. the priority assigned to a connected device
• D. the activity of a connected device

50. ECE Board Exam November 1996

Ethernet is baseband system using CSMA/CD operating at

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

51. ECE Board Exam November 1996

A microwave communications system space loss calculation formula is

• A. 92.4 + 10 log f +20 log d
• B. 94.2 + 10 log f +20 log d
• C. 92.4 + 20 log f + 20 log d
• D. 94.2 + 20 log f +20 log d

52. ECE Board Exam November 1996

Which is the non-resonant antenna?

• B. Folded Dipole
• C. Rhombic antenna
• D. End fire array

53. ECE Board Exam November 1996

The first commercial satellite

• A. Explorer
• B. Sputnik
• C. Telstar
• D. Early bird

54. ECE Board Exam November 1996

A quadrature signaling have ________ possible states.

• A. 16
• B. 8
• C. 32
• D. 4

55. ECE Board Exam November 1996

Proposed the use of a clad glass fiber as a dielectric waveguide.

• A. Kao and Keck
• B. Karpon and Keck
• C. Karpon and Bockham
• D. Bockham and Kao

56. ECE Board Exam November 1996

What band does VSAT first operate?

• A. X-band
• B. C-band
• C. Ku-band
• D. L-band

57. ECE Board Exam November 1996

What is the method of diversity reception where the signal is transmitted on 2 different frequencies over the same path?

• B. Frequency
• C. Polarization
• D. Space

58. ECE Board Exam November 1996

The wavelength of light has no role in

• A. Diffraction
• B. Interference
• C. Resolving power
• D. Polarization

59. ECE Board Exam November 1996

Which of the following filters block FM radio band for TV channels (2 to 13)?

• A. High-pass filter
• B. Band reject filter
• C. Low-pass filter
• D. Band-pass filter

60. ECE Board Exam November 1996

The standard ASCII

• A. is version II of ASC
• B. is used only in US and Canada
• C. has 132 characters including 32 control characters
• D. is subset of 8-bit EBCDIC code

61. ECE Board Exam November 1996

Luminous efficiency is least for a

• A. mercury vapor lamp
• B. low-wattage light bulb
• C. high-wattage light bulb
• D. fluorescent tube

62. ECE Board Exam November 1996

Transmission lines when connected to antenna have

• B. resistive load whose resistance is less than characteristics impedance
• C. resistive load at the resonant frequency
• D. resistive load whose resistance is greater than the characteristic impedance of the line

63. ECE Board Exam November 1996

What is the free space loss, in dB, between two microwave parabolic antennas 38.0 kilometer apart operating at 7.0 GHz?

• A. 145.6 dB
• B. 138.5 dB
• C. 135.5 dB
• D. 140.89 dB

64. ECE Board Exam November 1996

What is the equivalent output of a circuit in dBm, if it is has an output of 10 watts?

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

65. ECE Board Exam November 1996

Satellite engine use

• A. liquid fuel
• B. jet propulsion
• C. ion propulsion system
• D. solar jet

66. ECE Board Exam November 1996

• A. RIMPATT
• B. TRAPATT
• C. Magnetron
• D. IMPATT

67. ECE Board Exam November 1996

Transmission line must be matched to the load to

• A. transfer maximum voltage to the load
• B. transfer maximum current to the load
• C. reduce the load current
• D. transfer maximum power to the load

68. ECE Board Exam November 1996

Electromagnetic wave travel at __________ in free space.

• A. 300,000 km/sec
• B. 100,000 km/ sec
• C. 400,000 km/sec
• D. 200km/sec

69. ECE Board Exam November 1996

When electromagnetic wave are propagated through a waveguide, they

• A. are reflected from the walls but do not travel along them
• B. travel along all four walls of the waveguide
• C. travel along the broader walls of the guide
• D. travel through the dielectric without touching the walls

70. ECE Board Exam November 1996

Codes must be

• B. eight bit per character
• C. the same in all modern computer
• D. either seven or eighth bits per character

71. ECE Board Exam November 1996

Combination of modulator, channel and detector.

• A. Transceiver
• B. Discrete channel
• C. T/R channel
• D. Transponder

72. ECE Board Exam November 1996

What is the stage of the sand becoming silicon?

• A. Hot
• B. Gas
• C. Liquid
• D. Molten

73. ECE Board Exam November 1996

Noise reduction system used for film sound in movie

• A. dBx
• B. dolby
• C. dBa
• D. dBm

74. ECE Board Exam November 1996

What is the principal difference between asynchronous and synchronous transmission?

• A. The clocking is mixed with the data in synchronous transmission
• B. The pulse height are difficult
• C. The clocking is derived from the data in synchronous
• D. The bandwidth required is difficult.

75. ECE Board Exam November 1996

You are measuring a voice channel at a -4 dB test point level, the meter reads -73 dBm (pure test tone) convert the reading in dBmCO.

• A. 16
• B. 18
• C. 22
• D. 12

76. ECE Board Exam November 1996

What is the type of emission use by standard AM radio broadcast?

• A. A0
• B. F3
• C. A3
• D. A5C

77. ECE Board Exam November 1996

____________ is the average rate of transmission of sound energy in a given direction through a cross sectional area of 1 sq.m. at right angle to the direction.

• A. Sound pressure
• B. Sound intensity
• C. Pressure variation
• D. Loudness

78. ECE Board Exam November 1996

Top loading is used in an antenna in order to increase its ___________.

• A. input capacitance
• B. beamwidth
• C. bandwidth
• D. effective height

79. ECE Board Exam November 1996

What component in the telephone set has the primary function of interfacing the handset to the local loop?

• A. Varistor
• B. Induction coil
• C. Resistor
• D. Capacitor

80. ECE Board Exam November 1996

The first passive satellite transponder.

• A. Early bird
• B. Score
• C. Moon
• D. Sputnik

81. ECE Board Exam November 1996

The primary purpose of the data modem is to

• A. interface analog terminal equipment to analog communications channel
• B. interface digital terminal equipment to analog communications channel
• C. interface analog terminal equipment to digital communications channel
• D. interface digital terminal equipment to digital communications channel

82. ECE Board Exam November 1996

____________ is the out-of-band signaling between toll central offices (Bell System Standard)

• A. 2,000 Hz
• B. 800 Hz
• C. 3,835 Hz
• D. 3700 Hz

83. ECE Board Exam November 1996

Which symbol indicates that only one sideband is transmitted?

• A. A3E
• B. B8E
• C. C3F
• D. H3E

84. ECE Board Exam November 1996

A voice-grade circuit using the PTN has an ideal passband of

• A. 0 to 4 Hz
• B. 0 to 4 kHz
• C. 0 to 4 GHz
• D. 0 to 4 MHz

85. ECE Board Exam November 1996

1 micron is equal to ___________ meter(s).

• A. 10-6m
• B. 10-3 m
• C. 106 m
• D. 109 m

86. ECE Board Exam November 1996

The lowest resistance grounding on earth

• A. Sand
• B. Clay
• C. Surface loam soil
• D. Limestone

87. ECE Board Exam November 1996

Troposheric scatter uses the frequencies in the ________ band.

• A. VLF
• B. UHF
• C. VHF
• D. UF

88. ECE Board Exam November 1996

The unit of pitch

• A. Decibel
• B. Phon
• C. Mel
• D. Sone

89. ECE Board Exam November 1996

What kind of receiver is used in conventional telephone handset?

• A. Capacitor
• B. Carbon
• C. Electromagnetic
• D. Ceramic

90. ECE Board Exam November 1996

Basic speed rate of digital system.

• A. 144 kbps
• B. 1,544 kbps
• C. 64 kbps
• D. 2,048 kbps

91. ECE Board Exam November 1996

A horizontal antenna is

• A. centrally polarized
• B. vertically polarized
• C. horizontally polarized
• D. perpendicularly polarized

92. ECE Board Exam November 1996

What is the diameter of a copper wire to be used in a 16 km loop with a dc loop resistance of 100 ohms/km?

• A. 0.108 cm
• B. 1.082 cm
• C. 0.017 cm
• D. 0.0465 cm

93. ECE Board Exam November 1996

If a fiber optic system has a rise time of 16 ns, the source rise time is 1.5 ns and the detector rise time is 2 ns, what is the cable rise time?

• A. 14 ns
• B. 6 ns
• C. 9 ns
• D. 12.5 ns

94. ECE Board Exam November 1996

What is the phase delay of an 800 Hz voice signal if the phase shift is 15 degrees?

• A. 1.25 Âµsec
• B. 52 Âµsec
• C. 83.33 Âµsec
• D. 26 Âµsec

95. ECE Board Exam November 1996

What is the power loss of a telephone hybrid?

• A. 6 dB
• B. 2 dB
• C. 3 dB
• D. 1 dB

96. ECE Board Exam November 1996

You are measuring noise in a voice channel at 7 dB test point level. The meter reads -56 dBm (FIA weighted). What is the reading in dBrnc?

• A. 20
• B. 32
• C. 35
• D. 25

97. ECE Board Exam November 1996

Space diversity transmission means transmitting and receiving on

• A. two or more antennas operating on two different frequencies
• B. two or more identical frequencies
• C. two or more different frequencies
• D. two or more antennas operating on the same frequencies

98. ECE Board Exam November 1996

Rules governing the transmission of digital information.

• A. Line protocol
• B. Isochronous
• C. Data communications
• D. Digital communications

99. ECE Board Exam November 1996

A digital identification associated with a cellular system

• A. SAT
• B. ESN
• C. MIN
• D. SIM

100. ECE Board Exam November 1996

____________ is measuring the propagated field strength over the projected service area

• B. None of these