# Communications Engineering Exam 10: ECE Pre-Board

Pre-Board Examinations in Communications Engineering Module 10 composed of previous Board Exams Questions. Familiarize each and every questions.

This is 100 items set of Practice Examination 10 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 10

Choose the letter of the best answer in each questions.

1. ________ is a standard whereby mobile phones can gain access to specially tailored Internet websites.

• A. Bluetooth
• B. GPRS
• C. WAP
• D. EDGE

2. What noise is a transient short-duration disturbance distributed essentially uniformly over the useful passband of a transmission system?

• A. Flicker noise
• B. Transit-time noise
• C. Shot noise
• D. Impulse noise

3. What is the insertion loss of connector type splices for a single mode optical fiber?

• A. 0.51 dB
• B. 0.49 dB
• C. 0.31 dB
• D. 0.38 db

4. In the European standard, the aurial transmitter maximum radiated power is ______ of peak visual transmitter power.

• A. 10%
• B. 30%
• C. 20%
• D. 40%

5. What is the common up-converter and down-converter IF for microwave communications?

• A. 60 MHz
• B. 80 MHz
• C. 120 MHz
• D. 70 MHz

6. What is the data link protocol that is used in asynchronous transmission for transferring files from one computer to another?

• A. A modem
• B. X modem
• C. B modem
• D. C modem

7. What distortion is not caused by transmission line characteristics?

• A. Phase distortion
• B. Pulse shape distortion
• C. Spacing bias distortion
• D. Amplitude distortion

8. What is the effective radiated power of a repeater with 200 watts transmitter power output, 4 dB feline loss, 4 dB duplexer and circulator loss, and 10 dB antenna gain?

• A. 317 W
• B. 2000 W
• C. 126 W
• D. 260 W

9. Which of the following is standardized as part of GSM phase 2+ that can offer theoretical data speeds of up to 115 kbit/s?

• A. EDGE
• B. GPRS
• C. WAP
• D. Bluetooth

10. A ______ is essentially a cell site that is mounted on a flatbed tractor-trailer used for emergency purposes.

• A. COW
• B. BULL
• C. CALF
• D. PONY

11. Which of the following best describes a dip-meter?

• A. An SWR meter
• B. A counter
• C. A variable LC oscillator with metered feedback current
• D. A field strength meter

12. Which is space diversity system?

• A. Two or more antennas operating on two different frequencies?
• B. Two transmitters operating at same frequencies
• C. Two or more antennas operating on the same frequency
• D. Two antennas from two different transmitters

13. What part or section of a TV receiver that separates the sound and video signals?

• A. IF stage
• B. Video amplifier
• C. Video detector
• D. Burst separator

14. What is the channel number of an FM station with a carrier frequency of 99.5 MHz?

• A. 256
• B. 258
• C. 257
• D. 259

15. In a triple conversion superheterodyne receiver, diode mixer stages are operated

• A. In the linear region
• B. In the nonlinear region
• C. As class A amplifiers
• D. As class B amplifiers

16. In ISDN, what is the basic access B channel data rate?

• A. 32 kbps
• B. 64 kbps
• C. 144 kbps
• D. 16 kbps

17. What is the channel spacing for MF-HF voice frequencies?

• A. 2.8 kHz
• B. 500 Hz
• C. 3.5 kHz
• D. 3 kHz

18. What is the quantization signal-to-noise ratio if an 8-bit PCM code is used?

• A. 40 dB
• B. 50 dB
• C. 60 dB
• D. 65 dB

19. What is the emission designation of a single sideband reduced carrier signal?

• A. H3E
• B. J3E
• C. R3E
• D. B8E

20. What is the most commonly used intermediate frequency of radar receivers?

• A. 40 MHz
• B. 60 MHz
• C. 70 MHz
• D. 30 MHz

21. The input signal of a travelling wave tube is introduced at

• A. Cathode
• B. Anode
• C. Cathode end of the helix
• D. Collector end of the helix

22. What determines the ability of radar to determine the bearing to a target?

• A. Speed of light
• B. Speed of target
• C. Antenna directivity
• D. Frequency of signal

23. What is the minimum number of bits required in a PCM code for a range of 10,000?

• A. 12
• B. 9
• C. 14
• D. 10

24. The antenna current is doubled when the modulation index is doubled in ______ AM system.

• A. A5C
• B. A3J
• C. A3
• D. A3H

25. Which of the following is not a bounded medium?

• A. Coaxial line
• B. Two-wire line
• C. Waveguide
• D. Free space

26. What is affected by the distance between the listener and the source of the sound because the intensity varies inversely with the square of the distance?

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

27. Comparing the capacities of a DVD and an ordinary CD, DVD is ______ time bigger than CD.

• A. 10
• B. 20
• C. 15
• D. 25

28. Locking on to a defined target is known as

• A. Homing
• B. Referencing
• C. Searching
• D. Defining

29. What causes the maximum usable frequency to vary?

• A. The temperature of the ionosphere
• B. The speed of the winds in the upper atmosphere
• C. The type of weather just below the ionosphere

30. What limits the sensitivity of a receiver?

• A. The power supply of the receiver
• B. The power output of a transmitter
• C. The noise floor of the receiver
• D. The distance between the transmitter and receiver

31. What is the standard test tone used for audio measurements?

• A. 100 Hz
• B. 500 Hz
• C. 1000 Hz
• D. 2000 Hz

32. What causes image interference?

• A. Low gain
• B. High IF
• C. Poor front-end selectivity
• D. Low signal-to-noise ratio

33. What frequency band is referred to as the metric waves?

• A. VHF
• B. UHF
• C. HF
• D. SHF

34. A waveguide passive component that brings a smooth change in the direction of axis maintained perpendicular to the plane of polarization?

• A. L bend
• B. H bend
• C. T bend
• D. X bend

35. How far is the visual carrier from the lowest frequency in the spectrum of a monochrome TV broadcast channel following the NTSC standard?

• A. 1.5 MHz
• B. 1.25 MHz
• C. 4.5 MHz
• D. 0.25 MHz

36. What aircraft deviation is measured by an ILS localizer?

• A. Altitude
• B. Ground speed
• C. Vertical
• D. Horizontal

37. Skip zone is otherwise known as

• A. Empty zone
• C. Null zone
• D. Zone of silence

38. In the American standard, the aural transmitter maximum radiated power is _____ of peak visual transmitter power.

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

39. What character signifies the start of the test for Bisync?

• A. STX
• B. SOH
• C. BCC
• D. ETX

40. A low frequency audible periodic variation in pitch of sound output in high fidelity sound reproduction system?

• A. Flutter
• B. Wow
• C. String vibration

41. When can a corporation or association incorporated under the Philippine laws and with foreign investors be granted radio station license?

• A. When 60% of the capital is owned by Filipino citizens
• B. When 50% of the capital is owned by Filipino citizens
• C. When the chairman of the board is a Filipino
• D. When the president of the corporation/association is a Filipino

42. ______ is a term in the test language for noise testing in telephone circuits that means a one-syllable word consisting of a consonant, a vowel, and another consonant.

• A. Logatom
• B. Nosfer
• C. Ore
• D. Belcore

43. Why are frequency modulation transmitters more efficient?

• A. Because their power is increased by class C amplifiers
• B. Because their power is increased by class A amplifiers
• C. Because their power is increased by class B amplifiers
• D. Because their power is increased by class AB amplifiers

44. A 1000W carrier is amplitude modulated to a depth of 85%. Calculate the total power of the modulated wave?

• A. 1361.25 W
• B. 680.62 W
• C. 1425 W
• D. 712.5 W

45. Which is not an ITU sector?

• A. ITU-W
• B. ITU-R
• C. ITU-T
• D. ITU-D

46. What is the process of cancelling the effect on internal device capacitance in radio transmitters?

• A. Degaussing
• B. Neutralization
• C. Ionization
• D. Stabilization

47. Which of the following is the basic synthesizer circuit?

• A. Frequency divider
• B. Frequency multiplier
• C. PLL
• D. Mixer

48. Which one is not an important characteristic of the physical layer?

• A. Electrical
• B. Logical
• C. Mechanical
• D. All of the choices

49. What is the typical separation between the two conductors in a parallel wire line?

• A. 0.001 to 0.01 m
• B. 200 to 500 mm
• C. 0.635 to 15.24 cm
• D. 2.5 to 5 in.

50. In t-carrier system, t3 has a bit rate of

• A. 560.160 Mbps
• B. 44.376 Mbps
• C. 44.736 Mbps
• D. 560.106 Mbps

51. In radio signal emission designation, the fifth symbol means

• A. Details of signals
• B. Type of information transmitted
• C. Nature of multiplexing
• D. Nature of signal modulating the main carrier

52. What is the channel spacing for SITOR frequencies?

• A. 500 Hz
• B. 170 Hz
• C. 300 Hz
• D. 3 kHz

53. Which of the following is the new name of CCITT?

• A. ITU-T
• B. ITU-R
• C. ITU-S
• D. ITU-D

54. Which of the following frequencies is normally used for distress and safety communications?

• A. 4209.5 kHz
• B. 490 kHz
• C. 518 kHz
• D. 2174.5 kHz

55. What is the difference between available power and power budget?

• A. Power margin
• B. Extra power
• D. System gain

56. A matched termination in which the electromagnetic energy is absorbed by water.

• A. Maximum power transfer
• D. Basin

57. What do you call the electrical conduction in a photosensitive material which is not exposed to radiation?

• A. Dark conductance
• B. Pure conductance
• C. Black out
• D. Super conductance

58. How many sidebands are present in the J3E mode?

• A. Two sidebands and a carrier
• B. One upper sideband
• C. One lower sideband
• D. Two carriers and one sideband

59. A component that samples the microwave signal travelling in one direction down to the transmission line

• A. Isolator
• B. Combiner
• C. Directional coupler
• D. Attenuator

60. What does OMB stand for?

• A. Optical media board
• B. Organization of medical biologist
• C. Optical medium board
• D. Optimum main board

61. A test method of comparing two audio systems by switching inputs so that the same recording is heard in rapid succession over one given system and then the other.

• A. B test
• B. A test
• C. AB test
• D. C test

62. And ITU-T specification code that deals with the telephone circuits.

• A. X series
• B. T series
• C. V series
• D. I series

63. What digital carrier transmits a digital signal at 274.176 Mbps?

• A. T1
• B. T3
• C. T2
• D. T4

64. What signal-to-noise ratio is required for satisfactory television reception?

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

65. How many telephone channels are there in AT 2 line?

• A. 50
• B. 90
• C. 83
• D. 96

66. What optical source radiates light uniformly in all directions?

• A. Isotropic source
• B. Lambertian source
• C. Voltage source
• D. Ideal source

67. What is the spectrum of stereophonic FM signal?

• A. 19 to 38 kHz
• B. 30 to 53 kHz
• C. 59.5 to 74.5 kHz
• D. 88 to 108 MHz

68. What is the required quality factor for an SSB filter with the following data: center frequency = 1 MHz, the desired attenuation level of the unwanted sideband = 80 dB and the separation between sidebands = 200 Hz?

• A. 1,250
• B. 12,500
• C. 125,000
• D. 25,000

69. What do you call the reflection of a part of incident light at the interface of two media that have different refractive indices?

• A. Snell’s reflection
• B. Fresnel reflection
• C. Lambertian reflection
• D. Huygen’s reflection

70. Which conference in the ITU-structure does the telecommunication standardization bureau report?

• A. World telecommunication standardization conference
• B. ITU-development sector
• D. The secretary general

71. What region around a broadcasting transmitter in which satisfactory reception of broadcasting signal is not obtained?

• A. Fringe area
• B. Primary are
• C. Secondary area
• D. Tertiary area

72. What do you call the random noise seen on radar display screen?

• A. Impulse noise
• B. Atmospheric noise
• C. Grass
• D. Johnson noise

73. Which of the following antennas receives signals equally well from all directions in a horizontal plane?

• A. Hetz antenna
• B. Vertical Marconi antenna
• C. Yagi antenna
• D. Helical antenna

74. Where is the brightness control located in a TV?

• A. The audio section
• B. The video section
• C. The grid-cathode circuit
• D. The front panel

75. What is the term used in telephony and telegraphy for irregular disturbing radiation due to various causes and in a particular produced by arc transmitters causing a rushing sound in receiving telephones?

• A. Fax tone
• B. Mush
• C. Hiss
• D. Crosstalk

76. What device in a waveguide system used for stopping or diverting electromagnetic wave as desired?

• A. Mechanical switch
• B. Electric switch
• C. Push-button switch
• D. Waveguide switch

77. What is the maximum power that can be obtained from a microwave tube at 10 GHz?

• A. 500 W
• B. 10 W
• C. 50 W
• D. 20 W

78. What do you call a cable consisting of twisted pairs of conductors, each separately insulated?

• A. Microstrip line
• B. Strip line
• D. Coaxial cable

79. What mixer type has the lowest spurious signals?

• A. Double-balanced
• B. Single-balanced
• C. Super-heterodyner
• D. Heterodyner

80. What are the electromagnetic radiations of wavelengths less than 300 angstroms?

• A. X-rays
• B. Ultraviolet rays
• C. Infrared
• D. Microwaves

81. What is known as the alignment of the three color guns to a common point?

• A. Confetti
• B. Divergence
• C. Convergence
• D. Synchronization

82. What is the department order that governs commercial radio operator?

• A. Department Order No. 5
• B. Department Order No. 23
• C. Department Order No. 88
• D. Department Order No. 44

83. The computer which initiates information transfer

• A. Master
• B. Station
• C. Slave
• D. Mainframe

84. Which of the following antennas require good grounding?

• A. Yagi antenna
• B. Hertz antenna
• C. Marconi antenna
• D. Isotropic antenna

85. Which circuit detects frequency modulated signal?

• A. Modulator
• B. Discriminator
• C. Demodulator
• D. Modem

86. What synchronization is provided so that the start and end of message is identified?

• A. Carrier
• B. Character
• C. Bit
• D. Clock

87. A form of regenerative repeater for transmitting signals over a long cable received through a relay in a clearer form.

• A. Active generator
• B. Active repeater
• C. Interpolator
• D. Audio generator

88. What is the minimum propagation delay of a geostationary satellite?

• A. 278 ms
• B. 239 ms
• C. 300 ms
• D. 600 ms

89. In measuring crosstalk using dBx unit the reference power is

• A. 1 mW
• B. 1 W
• C. 1 pW
• D. 6 mW

90. A spot on the sun’s visible surface where the magnetic flux lines converge?

• A. Sunspot
• B. Filament
• C. Solar spot
• D. Prominence

91. ______ is a slow moving large mass of plasma on the sun’s surface.

• A. Filament
• B. Solar flare
• C. Prominence
• D. Proton flare

92. ______ is slow moving “cord-like” mass of plasma across the sun’s surface.

• A. Filament
• B. Solar flare
• C. Prominence
• D. Solar spot

93. At what particular wavelength is solar flux measured?

• A. 10.7 mm band
• B. 10.7 m band
• C. 10.7 cm band
• D. 10.7 nm band

94. What is the approximate intensity of the magnetic field at the earth’s surface?

• A. 32,000 nT
• B. 62,000 nT
• C. 32,000 ÂµT
• D. 62,000 ÂµT

95. What is the intensity of the magnetic field at the earth’s north pole?

• A. 32,000 nT
• B. 62,000 nT
• C. 32,000 ÂµT
• D. 62,000 ÂµT

96. What do you call a satellite weighing less than 1 kg?

• A. Nanosat
• B. Picosat
• C. Femtosat
• D. Microsat

97. The first creature in space was carried by which of the following spacecrafts in November 3, 1957?

• A. Sputnik 1
• B. Sputnik 3
• C. Sputnik 2
• D. Explorer 1

98. The wireless evolution is achieved through the GSM family of wireless technology platforms which include but except one of the following. Which one is NOT a member of the GSM family?

• A. GSM
• B. EDGE
• C. GPRS
• D. CDMA

99. Which of the following is an enhancement of GSM including the GPRS?

• A. 1G
• B. 2.5G
• C. 2G
• D. 3G

100. A low power, short range wireless technology designed to provide a replacement for serial cables is called ______.

• A. WAP
• B. GPRS
• C. Bluetooth
• D. EDGE