This is the Section 1 Module 9 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 1 Module 9
1. 3 dB – signal level that must be kept within 6 MHz
2. 12 dB – other than 6 MHz
3. 12 dB – within the next 24 hours
4. 46 dB – visual signal level over RMS interference
5. 28 dB – minimum terminal match
6. 18 dB – front-back ratio
7. 16 dB – RF output terminal match
8. 13 - 17 dB – level of attenuation of aural signal with respect to the video signal
9. 80 dB – In CATV, cross modulation of trunk amplifiers
10. 60 dB – In CATV, spurious signal rejection
11. 40 dB – In CATV, sound section isolation
12. Positive – carrier shift due to insufficient grid excitation; grid modulation
13. Negative – carrier shift due to insufficient grid excitation; high level
14. Trailing wire – submarine wire
15. 1.35 cm to 1.7 mm – wavelengths where water vapor molecule absorption peaks
16. 5 mm to 2.5 mm – wavelengths where oxygen molecule absorption peaks
17. 1520 m/s – speed of sound in water at 25oC
18. Intelsat – 21 satellites
19. Buncher – velocity modulates the beam
20. Antonio Meucci – “first inventor” of telephone
21. 1.5 ms – line turn around
22. 300 – 2000 nm – sunlight wavelength
23. 500 nm – peak sunlight wavelength
24. Patch antenna – antenna that uses microstrips
25. 19.39 Mbps – data rate of a 6MHz terrestrial TV
26. 27 Mbps – data rate of a 6MHz CaTV
27. Acoustician – practitioner of acoustics
28. ¼ mile absolute and 100 feet relative – precision Loran C/D
29. 460 m – accuracy of LORAN C
30. MLS – no global coverage
31. Between Channels 6 and 7 and above Channel 13 – used in CATV
32. Video Preamplifier – not tuned to the 3.58MHz signal
33. Noncomposite signal – video signal without sync signal
34. 1:1.38 – minimum VSWR for CATV
35. 42H – blanked during vertical retrace
36. Hash – short bit sequence sent typically 128bits in digital signatures
37. Public key encryption – encryption of data is most commonly achieved through
38. Private key encryption – enables decryption of Public key encrypted data
39. 8 kbps – Speech coding rate of D-AMPS
40. 7:8 – principal musical interval considered as dissonant
41. LEO satellites – 200 satellites
42. 100 Base Tx – Ethernet Standard 3-Level Manchester
43. 20 mins – maximum daily exposure in minutes for a loudness level between 100 –110 dB
44. 10 milliroentgens – 30 cm
45. 0.5 milliroentgens – 5 cm
46. 10 cm – area with no dimensions rather than 5cm
47. 1.6 s - 1.8 s – reverberation time for an auditorium
48. 1.4 -3.4 s - reverberation time for a church
49. 120 dB – threshold of pain
50. 4 MHz – approximate critical frequency of E layer
51. 8 MHz – approximate critical frequency of F2 layer
52. 20 phons – typical loudness level of watch ticking
53. 3100 kHz – carrier frequency of supergroup 10
54. 3300 m/s – velocity of sound in wood
55. NTC Commissioner – Gamaliel Ala lang. Cordoba
56. V.32 – full-duplex transmission over two-wire at 9,600bps
57. V.90 – 56,000 bps
58. Physical dimensions – affects resonant frequency of a Gunn diode
59. 150 uV – minimum input to a preamplifier
60. 5150 m/s – speed of sound in steel
61. 10-12 W/m2 – threshold of audibility
62. 6 months - average lead time to install a new base station is approximately ____ to a year.
63. Distance-to-reuse ratio – geographic distance required between calls using identical frequencies in order to avoid interference
64. Cochannel Interference Reduction Factor (CIRF) – ratio of the separation distance between cochannel cell to the cell radius
65. 4130 km – single-hop nighttime range for F2 layer
66. ±12 kHz – maximum frequency deviation for cellular radio
67. Transmission loss – amount of sound reduction provided by a barrier - wall, floor or ceiling
68. 6 to 10 dB – sound level most commonly perceived by people
69. 4 – number of octaves of a basic voice band
70. 10 – number of octaves of human hearing
71. Rhythm – sonic time pattern
72. RG-62A/U – impedance of 93Ω
73. Twin-lead – velocity factor of about 0.8
74. 0.9 – velocity factor of open-wire line
75. 100 m – Ethernet system 10 Base T restriction
76. Cognitive – information related to mental processes of knowledge, reasoning, judgment, and perception
77. Delay line – transmission line used specifically for the purpose of achieving delay
78. Ephemeris – location of a celestial body in space
79. TTC – monitors onboard conditions such as temperature and battery voltage
80. 4 MHz – guardband between transponder channels
81. Helmholtz resonator – efficient absorption is only possible over a very narrow band approaching 1.0
82. Erlang B – calls not immediately satisfied at first attempt are cleared and do not reappear during the testing period
83. Erlang C – held in the system until satisfied
84. Poisson – held in the system until satisfied or abandoned
85. EO 196 – use of Philippine Communications Satellite
86. EO 467 – operation and use of international satellite communications
87. EO 109 – improve the provision of local exchange carrier service
88. EO 59 – compulsory interconnection of authorized public communications carrier
89. Glass – fiber optic with the least loss
90. 2860 W – input to a 2 kW transmitter
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