Communications Engineering Coaching Materials: Section 1 Module 9

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

Complete List of Communications Engineering Coaching Materials