You dont have javascript enabled! Please enable it! Communications Engineering Mastery Test 14: ECE Pre-Board

# Communications Engineering Mastery Test 14: ECE Pre-Board

This is 100 items Practice Examinations set 14 in Communications Engineering (Electronics Systems and Technology) composed of previous Board Exams Questions. Read each question and choice 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 question to increase the chance of passing the ECE Board Examination.

#### Start the Test Yourself Exam 14

Choose the letter of the best answer in each question.

1. An area within a wireless communications system where there is no coverage

• B. Hotspot
• C. Weakspot
• D. G-spot

Solution:

2. The worldโs first active repeater satellite

• A. Sputnik 1
• B. Telstar 1
• C. Courier 1B
• D. Echo 1

Solution:

3. Which FCC regulation governs the unlicensed ISM band?

• A. Subsection 11
• B. Chapter 11
• C. Part 15
• D. 815.00

Solution:

4. The person behind the first network email

• A. Ray Tomlinson
• B. Bill Gates
• C. Steve Jobs
• D. Tim Berner Lee

Solution:

5. What is the horizontal scanning time for 20 pixels?

• A. 1.5 ยตsecs
• B. 2.5 ยตsecs
• C. 2 ยตsecs
• D. 0.125 ยตsecs

Solution:

6. Calculate the maximum distance between base and mobile that can be accommodated with a guard time of 123 ยตs.

• A. 25.3 km
• B. 36.9 km
• C 8.5 km
• D. 12.4 km

Solution:

7. In a satellite system, Johannes Kepler stated that โthe square of the periodic time of orbit is proportional to the cube of the mean distance between the primary and the satelliteโ. This is also known as _____.

• A. Keplerโs 3rd law
• B. Keplerโs 2nd law
• C. Keplerโs 1st law
• D. Keplerโs law of areas

Solution:

8. A ghost is displaced 1 inch on a 13-inch diagonal TV screen. Determine the time between signal receptions, and the difference in path lengths.

• A. 3.53 km
• B. 1.53 km
• C. 2.53 km
• D. 0.53 km

Solution:

9. Slang term for someone who breaks an encrypted computer code or circuitry

• A. Programmer
• B. Cracker
• C. Engineer
• D. Hacker

Solution:

10. An FCC designation for any carrier or licensee whose wireless network is connected to the public switched telephone network and/or is operated for profit

• A. Gateway
• B. CMRS (Commercial Mobile Radio Service)
• C. PSTN (Public Switched Telephone Network)
• D VAN (Value Added Network)

Solution:

11. Placement of multiple antennas at a common physical site to reduce environmental impact and real estate costs and speed zoning approvals and network deployment

• A. Frequency reuse
• B. Collocation
• C. Multiplexing
• D. Duplexing

Solution:

12. Why is there a frequency term in the equation for free-space path loss?

• A. Atmospheric absorption
• B. Antenna geometry requires it
• C. Because of the distance involved
• D. There is no frequency term

Solution:

13. What is a primary advantage of offset-quadrature-phase shift-keying (OQPSK) over standard QPSK?

• A. Greater spectral efficiency
• B. More constant envelope power
• C. Greater data rates possible
• D. Lower noise density

Solution:

14. One of the standard units for radiation dosimetry, but is not applicable to alpha, beta, or other particle emission and does not accurately predict the tissue effects of gamma rays of extremely high energies.

• A. curie
• B. roentgen
• C. gray
• D. Sievert

Solution:

15. A moving target 0 degrees from the nose.

• B. on starboard bow
• D. on port quarter

Solution:

16. The monitoring, manipulating and troubleshooting of computer equipment through a wireless network

• A. Wireless ethernet
• B. Wireless IT
• C. WiFi (Wireless Fidelity)

Solution:

17. Consider a video signal that has a resolution of 640 x 480 pixels, with a frame rate 0f 30 Hz using progressive scanning. The luma signal is sampled using 8 bits/sample. The two chroma channels also use 8 bits/sample, but the color resolution is ยผ that is used for luma. Find the approximate bit rate for this signal, neglecting synchronization, error correction, and compression.

• A. 110.6 Mbps
• B. 1.6 Mbps
• C. 10.6 Mbps
• D. 11.6 Mbps

Solution:

18. The principle of data reduction which says that when reducing a set of data into the form of an underlying mode, one should be maximally non-committal with respect to missing data.

• A. Jaynes maximum entropy principle
• B. Maximum Entropy Principle
• C. Kullback principle of minimum discrimination
• D. Minimum discrimination principle

Solution:

19. A photodiode has a responsivity of 0.35 A/W; calculate the diode current if the input optical power is 400 nW.

• A. 400 nA
• B. 140 nA
• C. 35 nA
• D. 410 Na

Solution:

20. Which two systems are most likely to experience concurrent operation problems?

• A. Bluetooth + WLAN
• B. GSM + W-CDMA
• C. Bluetooth + AMPS
• D. WLAN + GSM

Solution:

21. Which best describes a bi-static radar?

• A. Uses static electricity for both transmitted and received signals
• B. Only detects fixed (non-moving) targets
• C. Fixed transmitter and fixed receiver at different locations
• D. Fixed transmitter and fixed receiver at the same locations

Solution:

22. In a network with 25 computers, which topology would require the most extensive cabling?

• A. Bus
• B. Star
• C. Mesh
• D. Ring

Solution:

23. Bluetooth is also known as

• A. IEEE 802.12.1
• B. IEEE 802.15x
• C. IEEE 802.11b
• D. IEEE 802.15.1

Solution:

24. Calculate the combined traffic intensity in Erlang for the following calls:

Trunk 1: 32min and 15 sec Trunk 2: 17min and 41 sec

Trunk 3: 6min and 22 sec Trunk 4: 15min and 3 sec

Trunk 5: 24min

• A. 5.78 Erlang
• B. 1.6 Erlang
• C. 24.12 Erlang
• D. 231.5 Erlang

Solution:

25. Calculate the noise voltage for a 1-kฮฉ resistor at 17ยฐ C โtunedโ by an LC circuit with a BW of 1 MHz.

• A. 50.1 ยตV
• B. 15.01 ยตV
• C. 535.01 ยตV
• D. 5.01 ยตV

Solution:

26. In 1800, ______discovered infrared light using a prism and a thermometer.

• A. William Herschel
• B. Johann Wilhelm Ritter
• C. Thomas Young
• D. Louis Malus

Solution:

27. The electric field of a GSM antenna at 90m distance

• A. 0.05 V/m
• B. 0.005 V/m
• C. 0.5 V/m
• D. 5 V/m

Solution:

28. In satellite terminology, LTO means

• A. low transfer orbit
• B. lift transfer orbit
• C. light transfer orbit
• D. lunar transfer orbit

Solution:

29. Parceling a spectrum license into two or more geographic areas

• A. Cell splitting
• B. Partitioning
• C. Zoning
• D. Spectruming

Solution:

30. The latest form of battery technology, allowing the highest power-to-weight ratio and no “memory effect,” which plagues batteries made from other materials

• B. Lithium Ion
• C. Nickel Metal Hydride

Solution:

31. An antenna system whose technology enables it to focus its beam on a desired signal to reduce interference

• A. Smart antenna
• B. Loop antenna
• C. Array system
• D. Parasitic arrays

Solution:

32. Procedure in which two base stations-one in the cell site where the phone is located and the other in the cell site to which the conversation is being passed- both hold onto the call until the handoff is completed

• A. Break before make
• B. Hard handoff
• C. Roaming
• D. Soft handoff

Solution:

33. The scientist who is credited with coining the word “television”.

• A. John Logie Baird
• B. Allen DuMont
• D. Constantin Perskyi

Solution:

34. Picture tubes have two black conductive coatings made of ________.

• A. Tellurium
• B. Phospor
• D. Arsenic

Solution:

35. Suppose that the aspect ratio of a TV system was change from 4:3 to 2:1, with the horizontal resolution keeping the same ratio to vertical resolution as at present. Assume the number of scan lines remains at present. How many details would have to be shown on a horizontal line?

• A. 428
• B. 338
• C. 674
• D. 525

Solution:

36. Calculate the apogee of a MEO satellite which has a minor axis of 10,000 mi and has an orbital eccentricity of 1/10.

• A. 2,357.6 mi
• B. 6,819.5 mi
• C. 5,527.7 mi
• D. 23,300 mi

Solution:

37. The polarization of light was discovered in 1808 by the French physicist __________.

• A. William Herschel
• B. Johann Wilhelm Ritter
• C. Thomas Young
• D. Louis Malus

Solution:

38. An inverse-square law indicating the magnitude and direction of electrostatic force that one stationary, electrically charged object of small dimensions exerts on another

• A. Newtonโs law
• B. Coulomb’s law
• C. Lenโz law
• D. Gaussโs law

Solution:

39. Courier 1B used approximately and

• A. 5,000 solar cells
• B. 19,000 solar cells
• C. 36,000 solar cells
• D. 22,300 solar cells

Solution:

40. Under section 1 of the proposed NTC memorandum circular on the rules and regulations on the allocation and assignment of 3G radio frequency band, what is the radio frequency band allocated for Band C and D to be used by 3G networks

• A. Band C : 1920 โ 1935 MHz/2110 โ 2125 MHz, Band D : 1935 โ 1950MHz/2125 โ 2140MHz
• B. Band C : 1950 โ 1965 MHz/2140 โ 2155 MHz, Band D : 1885 โ 1900 MHz/1965 โ 1980 MHz
• C. Band C : 2010 โ 2025 MHz, Band D : 1935 โ 1950 MHz/2125 โ 2140 MHz
• D. Band C : 1920 โ 1935 MHz/2110 โ 2125 MHz, Band D : 1950 โ 1965 MHz/2140 โ 2155 MHz

Solution:

41. In 1923 and 1929, _____ invented the Iconoscope television camera tube and Kinescope TV picture tube respectively.

• A. John Logie Baird
• B. Allen DuMont
• D. William Crookes

Solution:

42. The loss in single-mode fiber-optic cable due to the glass is about:

• A. 40 dB per km
• B. 4 dB per km
• C. 0.4 dB per km
• D. zero loss

Solution:

43. AM radio’s main limitation is its susceptibility to

• A. ignition noise
• C. transit time noise
• D. atmospheric interference

Solution:

44. A basic AM radio transmitter works by first _________ the modulating signal, then multiplying it with the _________ using a _________

• A. AC-shifting, modulation index, integrator
• B. DC-shifting, modulation index, frequency mixer
• C. AC-shifting, carrier wave, differentiator
• D. DC-shifting, carrier wave, frequency mixer

Solution:

45. For an Ethernet bus that is 500 meters in length using a cable with a velocity factor of 0.66, and a communication rate of 10 Mb/s, calculate the total number of bits that would be sent by each station before it detects a collision, if both stations begin to transmit at the same time.

• A. 5 bits
• B. 2.5 bits
• C. 50 bits
• D. 25 bits

Solution:

46. In a CATV system, CMTS stands for

• A. Cable Modem Terminal Server
• B. Cable Modem Transmission System
• C. Cable Modem Terminal System
• D. Cable Modem Transmission Server

Solution:

47. Which specification standard incorporates the Ethernet standard?

• A. EIA’s RS232C
• B. CCITT’s X.25
• C. IBM’s Token Ring
• D. IEEE’s 802.3

Solution:

48. Which of these is NOT a problem with using symmetric private key cryptography?

• A. brute force attack can be used to uncover key
• B. transporting key between users
• C. decrypting long messages takes too much time
• D. loss or theft of key nullifies security

Solution:

49. The _____ of the picture tube is the total angle that the beam can be deflected without touching the sides of the envelope.

• A. deflection angle
• B. critical angle
• C. optical angle
• D. envelope angle

Solution:

50. The method of measuring the absorption coefficient of sound which considers all angles of increase is called _________

• A. reverberation chamber method
• B. bounce back-to-back method
• C. distance method
• D. sound velocity method

Solution:

51. Which of the following is referred to as the disadvantage of using a squelch circuit?

• A. Effect of AGC is reduced for strong signals
• B. Very weak signal might not be received
• C. Receiver sensitivity is reduced for strong signals
• D. Receiver selectively is reduced for strong signals

Solution:

52. Picture tubes have two black conductive coatings made of _________.

• A. Tellurium
• B. Phospor
• D. Arsenic

Solution:

53. A wireless phone that uses mobile satellite service to send voice and data

• A. PDA
• B. Satellite phone
• C. Mobile phone
• D. Smart phone

Solution:

54. A unique number assigned to every wireless operator in the United States that is then programmed into the phones that subscriber’s to that service purchase

• A. System Identification Number
• B. Numeric Assignment Module
• C. Subscriber Identity Module
• D. International Mobile Subscriber Identity

Solution:

55. The world’s first operational packet-switching network, and the progenitor of the global Internet.

• A. DECNET
• B. ARPANET
• C. ISDN
• D. NMT

Solution:

56. A signaling technique that broadcasts the same signal over each site in a network

• A. Telecast
• B. Simulcast
• C. Polling
• D. Contention

Solution:

57. Federal government authorization for the use of specific frequencies or frequency pairs within a given allocation, usually at stated a geographic location(s)

• A. Spectrum division
• B. Spectrum assignment
• C. Spectrum alignment
• D. Spectrum cap

Solution:

58. Calculate the energy related to the frequency occupied by VLF.

• A. 124 ยตeV to 1.24 ยตeV
• B. 1.24 peV to 12.4 peV
• C. 12.4 peV to 124 peV
• D. 124 meV to 1.24 Ev

Solution:

59. Electromagnetic waves of much lower frequency than visible light were predicted by ________ and subsequently discovered by ________.

• A. Maxwell, Hertz
• B. Marconi, Hertz
• C. Hertz, Maxwell
• D. Gauss, Gilbert

Solution:

60. An international high-speed signaling backbone for the public switched telephone network

• A. Subscriber loop signaling
• B. Channel Associated signaling
• C. Signaling System 7
• D. DTMF signaling

Solution:

61. ________ governs the exchange of sequential data

• A. IBM SNA
• B. SDLC
• C. FTP
• D. TCP

Solution:

62. The integration of wireless communications, vehicle monitoring systems, and location devices

• A. Cellular
• B. Telematics
• C. Networking
• D. Telewireless

Solution:

63. ______ routes outgoing and recognizes incoming messages

• A. IP
• B. TCP
• C. HDLC
• D. ATM

Solution:

64. In 1983, _____ protocols replace the Network Control Program as the principal protocol of the ARPANET

• A. HDLC
• B. TCP/IP
• C. BISYNC
• D. SPX/IPX

Solution:

65. The first email was sent in

• A. 1951
• B. 1961
• C. 1971
• D. 1981

Solution:

66. Europe’s approach to standardization for third-generation cellular systems

• A. IMT-TC
• B. UMTS
• C. 3GPP
• D. CDMA2000

Solution:

67. The first satellite to use Nickel Cadmium storage batteries.

• A. Courier 1B
• B. Explorer 1
• C. Score
• D. Early Bird

Solution:

68. In 1801, ______ discovered ultraviolet light using silver chloride, and again a prism.

• A. William Herschel
• B. Johann Wilhelm Ritter
• C. Thomas Young
• D. Louis Malus

Solution:

69. The angle from the ascending node to perigee, measured in the orbital plane at the earthโs center, in the direction of satellite motion.

• A. Argument of perigee
• B. Mean anomaly
• C. True anomaly
• D. Right ascension of the ascending node

Solution:

70. A unipolar NRZ line code is converted to a multiple-level signal for transmission over a channel. The number of possible values in the multilevel signal is 32, and the signal consists of rectangular pulses that have a pulse width of 0.3472 ms. What is the equivalent bit rate for the multilevel signal?

• A. 28.8 kbps
• B. 56 kbps
• C. 7.2 kbps
• D. 14.4 kbps

Solution:

71. Ethernet uses a ________ physical address that is imprinted on the network interface card (NIC).

• A. 32-bit
• B. 6-byte
• C. 64-bit
• D. 32-byte

Solution:

72. The range of an IRDA system is ________.

• A. 1 foot
• B. 10 feet
• C. 1 meter
• D. 10 meters

Solution:

73. A third-generation wireless standard proposal based on TDMA technology that was developed by the Universal Wireless Communications Consortium and is one of the 3G candidates submitted to the International Telecommunication Union by the United States

• A. IMT-TC
• B. DECT
• C. EDGE
• D. UWC-136

Solution:

74. A limit to the allocated spectrum designated for a specific service

• A. Guardband
• B. Spectrum tolerance
• C. Drift
• D. Spectrum cap

Solution:

75. Satellites receive dishes for telemetry and other remote monitoring, usually smaller than VSATs

• A. picoSAT
• B. USAT
• C. nanoSAT
• D. XSAT

Solution:

76. A protocol designed for advanced wireless devices allowing the easy transmission of data signals, particularly Internet content, to micro-browsers built into the device’s software

• A. Bisync
• B. WAP
• C. TCP
• D. SMTP

Solution:

77. What circuit combines signals from an IF amplifier stage and a beat-frequency oscillator (BFO), to produce an audio signal?

• A. A power supply circuit
• B. An AGC circuit
• C. A detector circuit
• D. A VFO circuit

Solution:

78. The Institute of Electrical and Electronics Engineers standard for wireless local area network interoperability

• A. 802.10.x
• B. 802.11.x
• C. 802.12.x
• D. 802.13.x

Solution:

79. What two factors determine the sensitivity of a receiver?

• A. Intermodulation distortion and dynamic range
• B. Cost and availability
• C. Dynamic range and third-order intercept
• D. Bandwidth and noise figure

Solution:

80. What is the term for the average power supplied to an antenna transmission line during one RF cycle at the crest of the modulation envelope?

• A. Peak output power
• B. Peak envelope power
• C. Peak transmitter power
• D. Average frequency power

Solution:

81. ________ amount of material which will produce 1 nuclear decay per second.

• A. 1 roentgen
• B. 1 becquerel
• C. 1 curie

Solution:

82. What circuit has a variable-frequency oscillator connected to a driver and a power amplifier?

• A. A single-sideband transmitter
• B. A VFO-controlled transmitter
• C. A crystal-controlled transmitter

Solution:

83. A collector modulated class c amplifier has a carrier output power of 100 W, and with an efficiency of 60 %, calculate the transistor power dissipation, assuming that all the power dissipation that occurs comes from the transistor.

• A. 34 W
• B. 66 W
• C. 60 W
• D. 100 W

Solution:

84. As per NTC M.C. 07-08-2004 an MPSC (Mobile Phone Service Center) shall properly identify its business and location by posting conspicuously at the entrance of its premises a signboard of at least ________ dimension which shall indicate clearly its business name, the type of services it offers, its full business address and the MPSC permit number.

• A. 50 cm x 150 cm
• B. 100 cm x 50 cm
• C. 50 cm x 100 cm
• D. 150 cm x 100 cm

Solution:

85. A single-mode fiber is made with a core diameter of 10 ยตm and is coupled to a light source with a wavelength of 1.3 ยตm. Its core glass has a refractive index of 1.55. Determine the maximum value of the fractional difference of the index.

• A. ฮ = 0.000206
• B. ฮ = 0.00806
• C. ฮ = 0.00206
• D. ฮ = 0.00086

Solution:

86. The most common screen phosphor is P1 for ______ screen.

• A. blue
• B. green
• C. red
• D. yellow

Solution:

87. The drum of a facsimile machine is 70.4 mm, and the scanning is 0.2 mm per scan. Calculate the index of cooperation for CCITT and IEEE standards respectively.

• A. 245, 123
• B. 353, 1106
• C. 1106, 353
• D. 1432, 144

Solution:

88. A specification from the Consultative Committee on International Telephone and Telegraph on layered protocols connecting computer terminals to a public, packet-switched network

• A. Frame Relay
• B. ISDN
• C. X.25
• D. IP (Internet Protocol)

Solution:

89. The acute radiation exposure effect of 100-200 dose of rems is ________.

• A. Slight blood changes
• B. Significant reduction in blood platelets and white blood cells
• C. Severe blood damage, nausea, hair loss, hemorrhage, death in many cases
• D. Death in less than two months for over 80%

Solution:

90. Voltage of typical X-ray tube

• A. 2 to 20 kV
• B. 10 to 20 kV
• C. 30 to 200 kV
• D. 3 to 20 KV

Solution:

91. What circuit uses a limiter and a frequency discriminator to produce an audio signal?

• D. A variable-frequency oscillator

Solution:

92. A special fee that local phone companies are allowed to charge customers for the right to connect with the local phone network.

• A. Access fee
• B. Toll charge
• C. Access charge
• D. Airtime

Solution:

93. A type of advanced smart antenna technology that continually monitors a received signal and dynamically adapts signal patterns to optimize wireless system performance

• A. Phased array antennas
• B. Helical antenna
• D. Parabolic antenna

Solution:

94. A mixer has the following input frequencies: RF = 800 MHz, LO = 870 MHz. The desired output frequency is 70 MHz. What is the image frequency?

• A. 500 MHz
• B. 940 MHz
• C. 140 MHz
• D. 1670 MHz

Solution:

95. In wireless technology, _____ refers to transporting voice and data traffic from a cell site to the switch

• A. Backbone
• B. Backhaul
• C. Routing
• D. Switching

Solution:

96. An enhanced system overlay for transmitting and receiving data over cellular networks

• A. X.75
• B. Packet switching
• C. Cellular Digital Packet Data
• D. Nordic Mobile Telephone

Solution:

97. What is the spurious-free dynamic range of a system with IP3 = +30 dBm and a minimum discernible signal (MDS) level of -90 dBm?

• A. 60 dB
• B. 80 dB
• C. 120 dB
• D. 150 dB

Solution:

98. A network technology for both local and wide area networks (LANs and WANs) that supports real-time voice and video as well as data

• A. Ethernet
• B. CSMA/CD (Carrier Sense Multiple Access/ Collision Detection)
• C. Wireless Ethernet
• D. ATM (Asynchronous Transfer Mode)

Solution:

99. A spectrum analyzer displays a component at 10 MHz @ 0 dBm, 30 MHz @ -10 dBm, 50 MHz @ -14 dBm, 70 MHz @ – 17 dBm, and all of the other odd harmonics until they disappear into the noise. What was the most likely input signal that caused the spectrum?

• A. A 10 MHz cosine wave (0 Vdc)
• B. A 10 MHz triangle wave (0 Vdc)
• C. A 10 MHz sawtooth wave (0 Vdc)
• D. A 10 MHz square wave (0 Vdc)

Solution:

100. On which side of a rectangular waveguide is an E-bend made?

• A. short dimension
• B. inside
• C. outside
• D. long dimension

Solution:

### Complete List of Communications Engineering Exams: ECE Pre-Board

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