# Communications Engineering Coaching Materials: Section 5 Module 8

This is the Section 5 Module 8 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.

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?

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?

### Complete List of Communications Engineering Coaching Materials

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