Communications Engineering Coaching Materials: Section 1 Module 6

This is the Section 1 Module 6 of the compiled Communications Coaching Materials taken from different sources including but not limited to Communications books, past Board Exams Questions, Journals and the Internet.

Communications Coaching Materials: Section 1 Module 6

This is the Section 1 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 1 Module 6

1. EO 436 – governing operations of CATV

2. EO 205 – regulation of CATV

3. Office Order 87-08-2004 – mobile phone dealer’s permit

4. 07-08-2004 – Mobile phone repair

5. 08-08-2004 – Mobile phone dealer/retail/base/purchase/sale

6. Horn – most commonly used microwave antenna

7. SSB – uses mechanical filters

8. Surface Acoustic Wave (SAW) filter – for RF filters (TV frequencies)

9. Plumbicon (lead oxide) – minimum lag

10. +6 VU (volume unit) – VF level to be placed on voice signals

11. +0 VU – VF level to be placed on telephone line/channel

12. Despun antenna – spins to focus on a fixed location on the earth

13. Attitude control – orientation of satellite on relationship to earth and sun

14. Apogee kick motor – rocket motor that is regularly employed on artificial satellites destined for a geostationary orbit.

15. TTC – Telemetry and Tracking Control

16. Helical antennas – used because of Faraday effect

17. Faraday screen – minimize losses (for transmitter)

18. Analog cell phone:

Class I – 0.6W

Class II – 1.6W

Class III – 3W

19. 121.5 MHz – aeronautical distress frequency

20. 2182 kHz – maritime distress frequency

21. LORAN C/D – 100 kHz; 460m or ¼ mile absolute accuracy, 100 m relative accuracy

22. Class I – Cable TV Channel/Station-- off-the-air channels, DBS feeds

23. Class II – w/o auxiliary equipment – scrambling

24. Class IV – provides signaling path

25. Discone antenna – vertical polarization; broadband

26. Cellular phone FM (AMPS) – ±12 kHz deviation

27. 5150 m/s – speed of sound in steel at 1 atm

28. TDM – 8 μs per time slot

29. AMPS – 10 kbps per channel

30. D-AMPS – 30 kbps – combines 3 AMPS channels

31. Cable TV:

16 dB - matching (RF)

28 dB – terminal isolation

40 dB – sound carrier isolator

60 dB – spurious radiation rejection

80 dB – cross modulation

-60 dB – adjacent channel isolation

± 1 dB – audio signal level

2 dB

36 dB – video SNR for modulator

32. 3G – UMTS (universal mobile telephone system); 2001

33. IS-95 – not TDMA; Direct Sequence Spread Spectrum- Mobile and Telephone

34. IMT 2000 – 144 kbps for fast vehicles; 384 kbps for pedestrians and slow vehicles

35. PD 1986 – MTRCB

36. EO 59 – mandatory interconnection of telecommunications networks

37. 1550 nm – used because of least losses

38. RA 9292 – approved by GMA on April 17, 2004

39. EO 196 – Philippine Satellite

40. Satellite closet – offshoot of TTC (building code)

41. Doppler radar – specialized radar that makes use of the Doppler effect to produce velocity data about objects at a distance.

42. Helmholtz resonator or Helmholtz oscillator is a container of gas (usually air) with an open hole (or neck or port).

43. GPS – 20,200km; 60° spacing between orbital planes; 6 orbital planes; 55° inclination

44. Poke-through –  in building construction (telephone installation); wires poke through fire-resistant floor

45. Firewire – connects cameras, etc. to computer

46. H.261 – video conferencing over telephone line

47. MP3 – MPEG-2 audio layer 3

48. MPEG-1 – low-rate video used in CD- ROM

49. MPEG-4 – DivX video compression

50. PL-259 – UHF connector

51. Type N connector – coax connector; expensive but good

52. 7:8 – dissonant tone ratio

53. Consonant tones – pleasant tones; antonym of dissonant

54. 1:1.38 – max. tolerable VSWR of something

55. American concert A – 440Hz

56. One octave above middle C – 524 Hz

57. Proxima centauri – nearest star to solar system

58. Aurora borealis – rapid fluttering; ionic disturbance

59. 10 octaves – human hearing range

60. Ionosonde – measures virtual height

61. Brillouin scattering – slight frequency change; modulation of light by the thermal energy in the material; produces phonons and photons

62. Mie scattering – caused by particles that have the size of wavelength

63. Splatter – excess sidebands

64. J3E – 1.4kHz difference between carrier and assigned frequency

65. F3 – for voice

66. Data rates:

GPRS – >170 kbps

EDGE – >384 kbps

3G – > 2 Mbps

67. 6 MHz terrestrial – 19.39 Mbps

68. 6 MHz data (cable modem) – 27 Mbps

69. CB SSB – 12W PEP

70. 3.1 m3/person – cinema volume level

71. NAVTEX – texting system for ships; maritime safety weather; narrowband direct printing telegraphy

72. Slot antenna – used for navigation systems; aerodynamic

73. Hole – for wavelength and waveguide wavemeter coupling

74. Probe – coupling for waveguide

75. Loop – coupling for waveguide

76. 4.5 MHz + 1 MHz – intercarrier

77. 1.25 MHz + 250 kHz – from lower edge

78. 3.579545 MHz – chroma subcarrier

79. V.90 – 56 kbps for telephone line

80. Flicker noise voltages:

0.02-0.2 μV – metal film

0.05-0.3 μV – carbon film

0.1-3.0 μV – carbon composition

0.01-0.2 μV – wirewound

81. IMT2000 – not 3G

82. 02 absorption – 5 mm, 2.5 mm

83. Water vapor – 1.35 cm, 1.7 mm

84. IMSI – international mobile subscriber identification

85. MIN – mobile ID number

86. WCDMA – 1.25W

87. DWDM – dense wavelength div mux

88. COW – cellsite; emergency purposes; on flatbed of tractor or trailer

89. Stripline – 2 ground planes; “sandwich”

90. Microstrip

91. 802.3 –  defacto Ethernet; CSMA/ CD LAN

92. 100 Mbps Ethernet – 100 m

93. Token ring – 4 or 16 Mbps

94. UTC – universal coordinated time

95. Why are cable channels converted to VHF from UHF? – to reduce losses in coax cable

95. Hard line – coax with hard shield

96. Twinax

97. Slow wave structure – forces electron beam to move slowly

98. C-band transponder guard band – 4 MHz

99. IF for TV receivers – 36-46 MHz

100. Electron spin –  in ferrites; due to magnetic field; precession

101. PVC – cover of coax

102. Polytetraflouroethylene – Teflon

103. Polyethylene – good for outdoor cables

104. Cross-over cable – low capacity/number of computers; will do in place of a hub

105. Electroluminescence – LED action

106. Radiometry – measuring RF spectrum

107. Photometry – technique of astronomy concerned with measuring the flux, or intensity of an astronomical object's electromagnetic radiation.

108. Luminosity – lumens/watt

109. Aperture antennaantenna aperture or effective area is a measure of how effective an antenna is at receiving the power of radio waves.

110. 40 km – microwave repeater distance

111. 56 km – TV broadcast radius

112. Omega – raw system; 88-98% of earth

113. Radar – depends on:

Distance – speed of pulse

Altitude – vertical beamwidth

Direction – directivity of antenna

114. UHF channel – noise figure 9 dB or better

115. RLE – takes advantage of redundancies in bit stream

116. GFSK – modulation used in Digital European Cordless Telephone (DECT)

117. GSM – 13 kbps speech coding rate

118. CATV and head-end operation – requires licensed commercial telephone operator

119. Critical frequency of E layer – 4 MHz

120. Gimmick – wire that acts as a capacitor; capacitance can be changes by bending wire to one side or another

121. Public key – for encrypting signal

122. Private key – for decryption

123. Why analog transmission rather than digital transmission of CATV in fiber optic medium? – easier to just modulate whole RF spectrum that having to demodulate, demux, encode, etc.

124. On-hook loop voltage (telephone) – -48 Vdc

125. Side tone – echo from Tx side to Rx side

126. Ringback – sent to the calling station to inform that call is in progress

127. Erlang C – blocked calls delayed until served/satisfied

128. Cell site D/R ratio – distance required before reuse; R – cellsite radius; “Cochannel Interference Reduction Factor”

129. Satellites – “spatial isolation” – frequency reuse by aiming beams at different locations (spaced-enough)

130. Base station – $500,000 - $750,000 to put up

131. 1 dB, 2 dB – visual signal level throughout video channel BW

132. Why is it easier to analyze transmission lines at low frequency? – low L and C, leaving only resistive component

133. Multi-mode fiber – easier to work with than single mode; wider acceptance angle

134. Why is height still important for mobile telephone transmitter antenna? – for more direct path; less reflections

135. Soliton – any optical field that does not change during propagation because of a balance between nonlinear and linear effects in a medium

136. SONET – brings together the North American and European digital mux hierarchies

137. Passive optical network – all-fiber access systems intended for residential applications

138. Single-mode fiber – width = 3 (wavelength of the light carrier)

139. Cryogenic cooling – lowers the operating temperature of receivers to reduce noise levels

140. SSB – envelope delay distortion test – 1800 Hz

Complete List of Communications Engineering Coaching Materials


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