Communications Engineering Coaching Materials: Section 5 Module 9

This is the Section 5 Module 9 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  5 Module 9

This is the Section 5 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 5 Module 9

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Questions

Answers

1

current frequency band given most attention for Satellite Communications

Ku

2

X-rays

30 to 0.3 Angstorms

3

space diversity transmission means transmitting and receiving on ______

two or more antennas operating on the same frequency

4

Ship-to-ship communications system is plagued by fading. Best solution seems to be the use of

Frequency Diversity

5

American concert pitch A is equivalent to

440Hz

6

International concert pitch A is equivalent to

435Hz

7

d band

2.20 to 3.30

8

lowest layer of ionosphere

D

9

highest layer of the atmosphere

Ionosphere

10

don't disappear at night

F2

11

next lowest layer

E

12

highest layer

F2

13

velocity factor of coaxial cable

0.6 to 0.8

14

velocity factor of transmission lines

0.5 to 0.9

15

government and military communication

NITA

16

related to mental processes of knowledge, reasoning, memory, judgment and perception

Cognitive

17

for navigation as well as marine and aeronautical communications and radar, ____ band is used

L

18

accepted official dimension of a mini-DV cassette package used in video recording in millimeters

66x48x12.2

19

NTC memorandum circular governs the rules and regulations about the manufacture, acquisition, sale and service of radio communication equipment

MC no. 02-05-88

20

a radio frequency in the UHF band of the radio spectrum

0.31250 GHz

21

when a space-wave signal passes over a mountain ridge, a small part of the signal is diffracted down the far side of the mountain

knife-edge diffraction

22

angle of inclination of GPS system

55°

23

bending of radius for fiber optic

350 mm

24

an analog video signal that carries the video data as two separate signals (brightness and color) is called

S-Video

25

a satellite beam that covers almost 42.4% of earth’s surface

global beam

26

V.42

link access protocol modem

27

multiple access technique used in GSM cellular system

TDMA

28

Connector is popular in attaching test instruments like oscilloscopes, frequency counters, spectrum analyzers.

BNC

29

to increase the transmission distance of UHF signal

increase antenna height

30

medium used by IBM token ring network that operates at either 4 Mbps or 16 Mbps

twisted pair

31

loudness level in which permanent damage to hearing is possible

150dB

32

coaxial cable connector is at least expensive and is widely used for TV sets, VCRs and cable TV

F-type connector

33

attenuator which connects passive two-ports

Calibration

34

primary cause of ionization

Ultraviolet Radiation

35

increase in sound level commonly perceived by most people

6 to 10 dB

36

sound pressure level if RMS sound pressure is 100microbars

114dB

37

coaxial connector is a more complex and expensive but do a better job in maintaining the electrical characteristics of the cable through the interconnections

N-type connector

38

PCS(personal communication system)

50 kHz

39

cocktail-end

binaural discrimination

40

capture effect

FM

41

acoustic behavior of gases

all of the choices (density, temperature, pressure)

42

spectrum bandwidth of a single GSM carrier

200kHz

43

noise figure having lowest noise

1.6dB

44

transistor having lowest noise figure

MESFET

45

noise outside the solar system

cosmic noise

46

ECT can apply for registration without examination

5years

47

ionosphere propagate by

space wave

48

maximize the skip distance

using the smallest possible radiation angle and highest possible frequency

49

space diversity

two or more antennas on the same wavelength

50

frequencies in the UHF range propagate by means of

space waves

51

VLF waves are used for some types of services because

they are very reliable

52

greatest advantage of FM over AM

FM amplitude is constant at all times

53

Companding

correlation

54

PCS(personal communication system)

45MHz

55

sound characteristic relates to a sonic time pattern

rhythm

56

typical center frequency spacing between adjacent channels (transponders) in satellites

40 MHz

57

orbital period of GPS constellation

12hrs

58

radiowave that is far from its source

plane wave

59

electric field that lies in a plane parallel to the surface of the earth

horizontal polarization

60

reference tone level for dBa

-85dBm

61

midband channel A-1

108 to 114 MHz

62

Huffman coding character contains bits

from 4 to 11

63

modulation technique used in data communications that is a variant of QAM that includes a method for forward error correction

trellis coding modulation

64

series modulation

system capable of generating high power

65

cellular standard known as the cdmaOne

IS-95

66

medium range

the one supported by IEEE 802.11 recommendation

67

most often used for outer covering of coaxial cables

PVC

68

Ethernet system is restricted only to 100m

10baseT

69

principal musical intervals is considered dissonant

7:8

70

light traveling in air optical fiber follow

snell

71

shortest wavelength in colors of light rays

blue

72

each point on a spherical wavefront may be considered a source of secondary spherical wavefronts

Huygen’s Principle

73

high frequency sound that cannot be heard by the human ear

ultrasonic

74

apparent loudness level of 80dB

very loud

75

ionoshpere causes radio signals to be

refracted

76

amount of sound reduction provided by a barrier-wall,floor or ceiling

transmission loss

77

perceptible sound repetition

echo

78

dispersion is the term used to describe

splitting of white light into its component colors in reflection

79

velocity of sound in air at 0 degrees Celcius

331.5m/s

80

in electromagnetic waves, polarization means

physical orientation of electric field in space

81

typical temperature range for installing fiber optical cable

-40 to 80 °C

82

station located on an object which is beyond and is intended to go beyond the major portion of the earth’s atmosphere

space station

83

atmospheric noise becomes less severe at frequencies

above 30MHz

84

a device that measures the internal open circuit voltage

psophometer

85

if the transmitter power remains constant, an increase in the frequency of the sky wave will

lengthen the skip distance

86

a light ray enters one medium from another along the normal. The angle of refraction is

dependent on the indexes of refraction

87

two directional antennas are pointed so that their beams intersect in the troposphere

troposcatter

88

run-length encoding

compress

89

best viewing distance of TV screen is ____ times the picture height

4 to 8

90

dielectric constant of polyethylene (PE) insulator

2.27

91

typical loudness level of an acoustic guitar 1 foot away

80 dB

92

IS-95

9.6kbps

93

satellite speed increases and its height in orbits gets ____

lower

94

satellite subsystem monitors onboard conditions such as temperature and battery voltage

and transmits this data back to a ground station for analysis

TTC

95

normally associated with specifying the location of celestial body in space

ephemeris

96

satellite subsystem provides stabilization in orbit and senses changes in orientation

attitude control subsystem

97

range of speech power

10 to 1000 microwatts

98

how does spatial isolation technique satellite communications avoid interference

employment of highly directional spot-beam antennas

99

polytetrafluoroethylene(PTFE) is also widely used insulator and is known as

teflon

100

in installing fiber cable, ____is a long-time use

tighter bends

101

designated as the international distress, safety and calling frequency for radio telephony for stations of the maritime mobile service when using frequencies in the authorized bands between 156 and 174 MHz

156.8 MHz

Complete List of Communications Engineering Coaching Materials


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