Communications Engineering Coaching Materials: Section 5 Module 12

This is the Section 5 Module 12 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 12

This is the Section 5 Module 12 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 12

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Questions

Answers

1

The HDTV has an aspect ratio of

16:9

2

The maximum frequency deviation in FM TV signal

25kHz

3

What is the mode of the waveguide is both the magnetic and electric field is parallel in the z-component

HE

4

What is the baseband frequency for basic super group?

312 – 552 kHz

5

What is the most commonly used antenna for satellite?

cassegrain antenna

6

At what speed do electromagnetic wave travel in free space

about 300 million meters per second

7

An electromagnetic field consists of

electric and magnetic field

8

the depth of an object submerged in a transparent liquid

always seems less than its actual

9

when a magnetic field is perpendicular to the surface of the earth, what is the polarization

horizontal

10

indicate which one of the following terms applies to troposcatter propagation

Fading

11

the grounds wave eventually disappear as one moves away from the transmitter because of

tilting

12

the shortest distance measured along the earth’s surface that a sky wave is returned to earth

skip distance

13

super refraction

ducting

14

commonly used for LNA

tunnel diode

15

channels 2, 4, 5, are

low band VHF

16

filter used for channel 2 to 13

band-reject filter

17

frequency for reverberation

500 Hz

18

space noise is observable at what range of frequencies

8 to 1.43 GHz

19

a mechanism or device which enables the TC camera to move in lateral and tilting motion

pan/tilt device

20

which is the first component of any MATV system to receive broadcast signals

antenna

21

time duration for horizontal trace

52 us

22

listing of the date and time of events, program etc malfunction and corrections in comm. Systems

log

23

the CCIR transmission standards for FM sound broadcast at VHF

Rec. 450.1

24

which of the class station is a regional channel

class III-B

25

CCIR standards for internal exchange of programmes on film for television

rec. 265.6

26

The channel for cable TV range frequency 5.75 – 11.75 MHz

T-1

27

The permissible power in kW of station II-A during nighttime is

0.25 – 50

28

MPEG -4 uses what media format

Divx

29

Glass tube of TWT in coating the aquadag _______

Provide attenuation

30

Maximum deviation ratio for TM

5

31

TV frequency band of channel 9

186 – 192 MHz

32

A means of beyond the line of sight propagation of UHF signals

Troposcatter propagation

33

Jet thrusters are usually fired to

maintains the altitude

34

The main function of a communication satellite is as a/an

repeater

35

A satellite stays in orbit because the following two factors are balanced

gravitational force and the centrifugal force

36

The maximum distance of an apogee of the ISS

358 km

37

What modulation is normally used with digital data?

QPSK

38

When the satellite are spaced 4 degrees of the 360 degrees complete circle, how many parking space or orbit slots are available

90

39

In ITU frequency allocation, the earth is divided into

3

40

What is the lifetime of ILDs?

50,000 hrs

41

Light goes from medium A to medium B at an angle of incidence of 40degrees, the angle of refraction is 30 degrees. The speed of light in B

is less than that in A

42

In a vacuum, the speed of an electromagnetic wave

is a universal constant

43

Distance near skip distance should be used for sky wave propagation

to prevent sky-wave and upper ray interference

44

Frequencies in the UHF range normally propagate by means o

space wave

45

Tropospheric scatter is used with frequencies in the following range

UHF

46

light of which the following has the shortest wavelength (red,yellow,blue,green)

blue

47

when a beam light enters one medium from another, a quality that never changes is its

frequency

48

a means of beyond the line of sight propagation of UHF signals

troposcatter propagation

49

type of radio wave responsible for long distance communication by multi skips is the

sky wave

50

System network Architecture uses what protocol

SDLC

51

EDGE stand for

Enhanced Data Rates for Global Evolution

52

AM type of emission

A3

53

Vestigial sideband emission

C3F

54

Fiber optics range of temperature during installation

0 – 60 degrees celcius

55

Range of Bluetooth

10 meters

56

Using GSM for EDGE, the date transfer rate is _____kbps

384

57

Multiplexing used for GSM, 1800 and 1900 MHz

CDMA

58

Most commercial satellite activity occurs in which band

C and Ku

59

when a magnetic field is parallel to the surface of the earth, what is the polarization

vertical

60

when a electric field is perpendicular to the surface of the earth, what is the polarization

vertical

61

local exchange area defined by the NTC that shares the same local exchange rates

local exchange service area

62

A sub-discipline of acoustics, it is the study of how sound is generated

Transduction

63

States the regulations on radio stations and communications

Act no. 3846

64

Frequency band of TDM

1900-1920 MHz ; 2010-2025 MHz

65

Numerical value of the gain of a n isotropic antenna

1.66

66

Maximum frequency deviation for FM

75 KHz

67

Frequency for color black

2300 Hz

68

Speech coding of 3G system

Adaptive multirate

69

Waveguide used by lower cut-off frequency is _____ attenuator

piston

70

Frequency band of industrial, scientific and medical purpose is ___ to ___ GHz

2.40 to 2.48

71

Class of radio station with 100kW effective radiated power

class C

72

Determining the amplitude of an FM sideband requires

Bessel function

73

SAW device can be used as

filter

74

Cordless phones beyond 300 ft uses how much power

10 W

75

Not an advantage of LEO satellites for wireless media

it uses digital signaling technique

76

Wi-Fi use

single carrier, direct sequence

77

Not a major section of laser

monitor

78

Noise reduction coefficient at perfect absorption

1.0

79

In fiber optics, splicing

active

80

Category 6 UTP has how many twisted pair

4

81

Advantage of PCM over PAM

superior noise immunity

82

How long is a 1Mbit image is transmitted using ISDN(64kbps)

120s

83

In power class E1, the nominal power radiated is ___ dBm

33

84

The ionosphere is a region of ionized gas in the upper atmosphere. The ionosphere is responsible for

long-distance radio communications

85

The main power source for a satellite are

solar cells

86

Most commercial satellite activity occurs in which band

C and Ku

87

Common Frequency used for Handy Phone

1.9 GHz

88

The lowest amount of frequency

resolution

89

The television picture tube magnetic field can be used for

beam focusing and beam deflection

90

AM image signal is rejected

prior to the mixer stage

91

The frequency of oscillation by a magnetron is mainly determined by

the dimension of each cavity resonator

92

In accordance with ITU specifications, the rate of the dispersion with wavelength for a a single mode fiber must be less than _____- ps/nm^2/km

0.95

93

Threshold point of QPSK is plus minus

0.875

94

Citizen frequency band radio service is _____

26.965 – 27.405 MHz

95

____ GHz/km

50 - 100

96

is a signalling message transmitted from the data communications equipment (DCE) indicating to the data terminal equipment (DTE) that it may begin data transmission

Clear to send

97

9-10

98

Videotext

99

30

Complete List of Communications Engineering Coaching Materials


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