This is the Section 5 Module 6 of the compiled Communications Coaching Materials taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies (EST), Communications Books, Journals and other Communications References. This particular Coaching Notes in Communications Engineering has random Questions and Answers in random topics. Make sure to familiarize each questions to increase the chance of passing the ECE Board Exam.
Communications Engineering Coaching: Section 5 Module 6
1. Pitch → The quality in sound that corresponds to color in light
2. 250 and 500 Hz → The maximum voice energy is located between
3. Volume unit meter → A device used to measure speech volume
4. AWG #19 → Which of the following is commonly used wire for subscriber loop design
5. Hybrid circuit → A device that converts a 2-wire circuit to a 4-wire circuit
6. GMSK → GSM uses what digital modulation technique?
7. Green → Which of the following wire is used to transmit signal?
8. 852 & 1209 Hz → The corresponding frequencies for digit 7 in the touch tone telephone is
9. 60 degrees → What is the beamwidth of the reflector of the receiving antenna in the base station?
10. 12 kHz → What is the frequency deviation of the cellular telephone system?
11. 1500 and 2300 Hz → In FM fax, the frequencies for black and white are
12. Vestigial sideband AM → Group 2 fax uses which modulation?
13. Group 3 → The most widely used fax standard is
14. QAM → Group 3 fax uses which modulation?
15. Thermal → Most fax printers are of which type?
16. 56 kbps → What is the transmission speed of group 4 fax?
17. 12 kHz → What is the max frequency deviation of an FM cellular transmitter?
18. 935 – 960 MHz → The base-to-mobile frequency assignment of a GSM system
19. 1.23 MHz → What is the bandwidth of cellular CDMA system?
20. Modified GSM → What is the system used by PCN?
21. Erlang C → Blocked calls delay conditions specified probability
22. GFSK → The modulation used by DECT
23. 890 – 915 MHz → The mobile-tobase frequency assignment for GSM system is
24. 13 → The range (in miles) of a cellular CDMA system
25. 900 THz → The bandwidth of optical fiber
26. 800 THz → Fiber optic cables operate at frequencies near
27. Inverted → An object farther from a converging lens than its focal point always has a /an _________image
28. Virtual → An object nearer to a converging lens than its focal point always has a/an _________ image
29. Larger → The real image formed by a spherical mirror is _______relative to its object
30. 200,000 hours → What is the lifetime of LEDs?
31. 50,000 hours → What is the lifetime of ILDs?
32. Step-index multimode → What type of fiber has the highest modal dispersion?
33. LED → Is a non-coherent light source for optical communications
34. Semiconductor → Which type of laser is the simplest to modulate directly by changing its excitation?
35. LED → Which of the following is used as an optical transmitter in the Fiber Optical
36. Single-mode graded index → Which of the following is not a common type of fiber optic cable?
37. dB/km → Cable attenuation is usually expressed in
38. 2 km → Which cable length has the highest attenuation?
39. X-rays → Which of the following is not part of the optical spectrum?
40. 400 – 750 nm → The wavelength of visible light extend from
41. Single-mode step index → Which type of fiber-optic cable is the most widely used?
42. Single-mode step-index → Which type of fiber-optic cable is best for very high speed data?
43. Single mode step-index → Which type of fiber-optic cable has the least modal dispersion?
44. 99.9999% → The ultrapure glass used to manufacture optical fibers is approx. ______ pure
45. Plastic-clad-silica → In fiber optics, PCS stands for
46. Ampere/Watt → What is the unit of responsitivity?
47. 700 – 1200 nm → Infrared range for fiber optics
48. higher losses → Which of the following is a disadvantage for plastic fiber optics
49. Optoisolator → An IC that represents a short distance one-way optical communications system
50. High losses → Why are visible-light LEDs not used for fiber optics?
51. 40 GHz → What is the frequency limit of an optical fiber?
52. 0.1dB → The mechanical splice attenuation loss is _______ dB or less
53. 1.5 → Refractive index of glass
54. 2.0 → Refractive index of diamond
55. 0.1 dB or less → How much is the power loss of the fusion splice?
56. Pan/tilt device → A mechanism or device which enables the TV camera to move in lateral and tilting motion
57. Wide angle → What class of TV camera lens used to cover short distances?
58. 955 – 2055 kHz → What is the local oscillator frequency in commercial AM broadcast if it is equal to 455 kHz?
59. +2000 kHz → What is the frequency tolerance of an FM Radio Broadcast station?
60. 1 → A newscast is a distinct unit of a program with a maximum news content of ________ minute(s) excluding intro, extro, headline and commercial load.
61. 15 → Commercial load for radio shall not exceed ____ minutes for one hour program in MetroManila
62. 17 → Commercial load for radio shall not exceed ______ minutes for one hour program outside metro manila
63. 6 → Program interruption for the airing of commercial in Metro Manila shall not exceed _____ breaks in every program hour
64. 6 → Program interruption for the airing of commercial outside Metro Manila shall not exceed _____ breaks in every program hour
65. 6:00 AM to 8:00 PM → For Metro Manila, the classification of prime time blocks for FM shall be
66. 52 microseconds → __________ is the time duration for one horizontal trace
67. A and B above (left to right, top to bottom) → For NTSC TV system, the image is scanned from choices
68. 525 → One complete NTSC scanning cycle field consists of how many lines
69. 15.75 Hz → What is the horizontal synch/ blanking pulse rate?
70. 60 Hz → What is the vertical synch/ blanking pulse rate?
71. Beam production → What is the purpose of an indirectly-heated cathode in a cathode ray tube?
72. 25 kHz → What is the max frequency deviation for audio modulation in TV transmission?
73. 4.5 → The video carrier and the audio carrier are separated by _______ MHz
74. 470 – 890 MHz → Range of a UHF television transmitter
75. Comb → __________ is the most effective filter for separating luminance and chrominance frequency components
76. 75% → What is the standard video level, in percent PEV for blanking?
77. 70% → What is the standard video level, in percent PEV for black?
78. Video detector → The sound and video signals are separated at the ______ of the TV receiver
79. F3F → Type of emission produced when a freq modulated transmitter is modulated by a TV signal
80. Contrast → Video signal amplitude determine the picture quality called
81. 88 – 108 MHz → The FM broadcast band is from
82. N → What is the first letter-symbol for emission of unmodulated carrier?
83. 180 – 186 MHz → Channel 8 frequency range allocation in cable TV
84. 5950 and 26100 kHz → International broadcasting (short wave) uses freq between ________ in accordance with international agreements
85. ITFS → Three stations are licensed to eligible educational entities for the distribution of program material to students enrolled in instructional curricula
86. 3 → For the allocation of frequency in the world, ITU divides the world into how many regions?
87. Sweep Generator → Voltage or current generator that displays time sweep on radar systems
88. Mark Generator → Shaping/generation of scale marks on a radar display
89. Weiner Filter
90. Gunn Effect → 3kW/cm
91. X-band → frequency band that is used in short range surveillance, long range tracking with high resolution and accuracy
92. L-band → frequency band that is used in long range surveillance with low resolution
93. VHF and UHF → frequency band that is used in long range surveillance with low to medium resolution and accuracy
94. Mm wave band → frequency band that uses very small antennas, airborne and space use
95. Aperture Blockage → blocking a portion of the aperture in radar systems
96. Grass → Noise in radar systems
97. Hit → Echo with a single pulse
98. APD → Fastest optical receiver
99. Echo box → receives a portion of the transmitted pulse and retransmits it back to the receiver as a slowly decaying transient
100. Eclipsing → radar system in which range ambiguity and range __________ are reduced by frequency diversity and alteration of pulse periodicity
101. Diffraction Radiation Generator