This is the Section 5 Module 8 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 8
1. Areocentric Orbit → An Orbit for planet Mars
2. Ionosonde → Use to measure or examine ionosphere
3. Gaussian Noise, White Noise, Thermal Noise → Noise from random acoustic or electric noise that has equal energy per cycle over a specified total frequency band
4. 290 K → Reference Noise Temperature
5. CCITT G. 151 → Standard that recommends crosstalk limit
6. CCITT Rec. G. 172 → Standard that utilized in inter-modulation noise rates on PCM audio channels
7. 800 Hz → Reference frequency of CCITT phosphometric noise measurement
8. 15 to 160 MHz → Industrial Noise
9. Crosstalk → Interference coming from other channel
10. -90 dBm → Reference noise level
11. frequencies above 30 MHz → Atmospheric noise or static is not a great problem at
12. -85 dBm → Reference level for noise measurement, F1A weighted
13. -90 dBm → Reference tone level for dBrn
14. Transit – Time Noise → Types of noise becomes of great importance at high frequencies
15. 11 years → The solar cycle repeats the period of great electrical disturbance approximately every
16. Solar Noise → Noise whose source is within the solar system
17. Noise Density → Total noise power present in a 1-Hz bandwidth
18. 90 → What is the relation in degrees of the electric and magnetic fields in an electromagnetic wave?
19. 3 to 30 MHz → High frequency Range
20. 3 KHz to 3 MHz → Medium Frequency Range
21. Always seems less than its actual depth → The depth of an object submerged in a transparent liquid
22. A fixed point in an electromagnetic wave → What is a wavefront?
23. 1 W → VHF ship station transmitters must have the capability of reducing carrier power to
24. Spread-Spectrum Communications → A wide bandwidth communications systems in which the RF carrier varies according to some predetermined sequence
25. Is greater than 1 → The index of refraction of a material medium
26. 12 GHz → Cannot be used in beyond-the-horizon terrestrial communications without repeaters
27. UHF → Tropospheric scatter is used with frequency range
28. may occur around the edge of a sharp obstacle → Diffraction of electromagnetic waves
29. X-rays → The highest frequencies are found in
30. 90 degrees → When a light ray approaches a glass-air interface from the glass side at the critical angle, the angle of refraction is
31. 8000 lx → The minimum illumination recommended for reading
32. Direct Wave → Microwave signals propagate by way of
33. 300 kHz to 3 MHz → Ground wave communications is most effective in
34. HF → Line-of-sight communications is not a factor in
35. Inverse Square Law → States the power density is inversely proportional to the distance from its source
36. MUF → Highest frequency that can be used for skywave propagation between two given points on earth
37. Diversity → Is not a cause of fading?
38. BPSK → Cellular CDMA system uses this type of modulation method
39. Attenuation → Is the progressive decrease of signal strength with increasing distance
40. towards the earth → If k-factor is greater than 1, the array beam is bent
41. 10 GHz → Rainfall is an important factor for fading of radio waves at frequencies above
42. Delayed Spreading → In microwave transmission using digital radio, what causes most inter-symbol interference?
43. waveguide match, cavity match, direct coax-helix match → Coupling into and out of a travelling wave tube can be accompanied by
44. Magnetron → A high-power microwave pulse of the order of megawatts can be generated by a
45. 1 to 100 GHz → Microwave frequencies are normally regarded as those in the range of
46. loran C: 100 KHz → Used for modern loran navigational system
47. Pulse Width → Pulsed frequency is equal to
48. 156.76 MHz and 156.8 MHz → Used by a Class-C Emergency Position Indicating Radio Beacon (E.P.I.R.B)
49. Radio Frequency → It is concerned in the design of an antenna system for pulsed radar set
50. LF Band → The operating frequency of loran C lies within the
51. 8000 MHz → A travelling-wave tube is used at frequencies in the order of
52. 22 GHz → Microwave frequency
53. Gunn → Popular microwave oscillator
54. Tunnel → Type of diode that does not ordinarily operate in reverse bias
55. Reflex Klystrons → Low-power Gunn diodes are replacing
56. Wider Bandwidth → The main advantage of a TWT over a klystron for microwave amplification
57. Klystrons → High power TWT’s are replacing what in microwave amplifiers?
58. 0.6 → The optimum clearance from an obstacle in a microwave system is accepted as ___ of the first Fresnel zone radius
59. Infinity → The microwave beam curves the same than that of the earth when the value of the correction factor k equals
60. Speed → The Doppler Effect allows which characteristics of a target to be measured?
61. Gunn Diode → Low-power radar transmitters and receivers use
62. 10 GHz → Typical radar frequency
63. K Band → A microwave band of 10.9 to 36 GHz
64. 92.4 + 20 log f + 20 log d → A microwave communications system space loss calculation formula
65. Litz Wire → A wire used to reduced skin effect The CCIR hypothetical reference circuit covering a distance of 2500 km consists of a total of how many hops?
66. 54 → The CCIR hypothetical reference circuit covering a distance of 2500 km consists of a total of how many hops?
67. 183 GHz → Water causes more attenuation particularly on what frequency?
68. 60 GHz → At what frequency does oxygen cause excessive attenuation?
69. 43500 MHz → What frequency does a radio altimeter operate?
70. 1300 Hz → RF carrier of the middle marker is modulated at
71. 30 → The first Philippine Mabuhay Satellite has how many channels?
72. 36 → The first Philippine agila 1 will have how many transponders?
73. 38 → AsiaSat 1 covers how many countries of Asia?
74. 200 dB → Approximate path loss from satellite-to-earth station
75. 0.5s → Delay time for satellite transmissions from earth transmitter to earth receiver
76. 500 MHz → The bandwidth of C-band satellite frequency band in US
77. 14 → A mobile satellite array has usually how many elements?
78. FDMA → A method of multiple accessing where a given RF channel bandwidth is divided into smaller frequency band
79. 22,300 mi → Height of satellite in a synchronous equatorial orbit
80. 3 GHz to 30 GHz → Most satellites operates at
81. FM → Type of modulation used on voice and video signal
82. Syncom 1 → The first satellite launched for a geosynchronous orbit but unfortunately lost during orbit injection
83. Square root of the dielectric constant → The velocity factor is inversely proportional with respect to the
84. 1710-1785 MHz → GSM 1800
85. 1930-1990 MHz → GSM 1900
86. Region 2 → In USA and England, what regional coding is for DVD
87. Quantizing Noise → Noise occurring in the presence of signal resulting from a mismatch between the exact value of an analog signal and the closest available quantizing step in a digital coder
88. Audimeter → Equipment use in measuring the ratings of a channel
89. Inter-carrier sound → In television, 4.5MHz is the
90. 2 Mbps → 802.11 legacy data rates approximately
91. 15 GHz → A waveguide has a cut-off frequency of 17GHz. Which signals will not be passed by the waveguide?
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