Communications Engineering Coaching Materials: Section 5 Module 14

This is the Section 5 Module 14 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 14

This is the Section 5 Module 14 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 14

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Questions

Answers

1

What is indicated by blinking in an LORAN system?

An error occurred in transmission

2

The primary coating of an optical fiber has a core diameter of _____ microns

250-750

3

The core diameter of a single-mode fiber optic available in the market

8 – 10 µm

4

Velocity that is the speed with which a constant phase is seen to be moving as a group

Group velocity

5

Dead Reckoning (DR) system used by helicopters

Doppler Reference Navigational System

6

Number of transponders of Philippine Agila II

30 transponders

7

Device used to connect non-ISDN equivalent to ISDN line

Terminal adapter

8

The bandwidth used by CDMA system

1.23 MHz

9

Superband is located above channel ___

13

10

Chrominance subcarrier frequency

1.8 MHz

11

Range of VHF transmitters

54 – 216 MHz

12

Angstrom is equal to __

10-4 µm

13

In CATV systems, the visual carrier is located at ___

1.25 MHz

14

According to NTC 03-03-2005A or the Rules and Regulations on Broadcast Messaging Service,Telcos with violations will have a penalty of ____per subscriber

P200

15

Department Order no.88, of MNTSC requires the supervision of an ECE in the operation and maintenance of a total of ___ stations or any other type of land stations

6

16

”cross-link”, the distance between two geostationary satellite (note: “crosslink” not sure.sorry)

60,000

17

Satellites that are newly launched have solar cells capable of supplying ___ watts

520

18

According to NTC 03-11-2005 or Registration of VoIP Service Providers and Resellers, Voip providers shall give as a performance bond, amounting to____

P5 million

19

The carrier frequency of FM station channel 288

105.5MHz

20

Camer lens aperture can be made smaller by “stopping down” the iris to an effective diameter of about 1/sqrt of 2 reduces light by ____

half

21

A sensor where external stimuli is used, allows to change optical path lengths, and also in the reinforcement/cancellations of light waves at the photo-detector

Birefringence sensor

22

A type of transmission that uses the connecting medium as a multi-channel device

Broadband transmission

23

A device used to connect different LANs to a common network

gateway

24

The power loss due to fusion splice

0.01dB to 0.1dB

25

The part of the ear that is auditory and has fluids

cochlea

26

The pitch to density relationship is given by: the change in frequency is ____

inversely proportional to the sqrt of change in density

27

A sensor wherein the birefringence is directly proportional to the square of electric field

Kerr cell

28

The minimum gain of channel 11 CATV

22dB

29

Interlacing used for pre-ISDN standard for basic rate access for ISDN environment

R interlace

30

VSAT operates at what band?

C-band

31

What is the most appropriate description for an ILS system?

An aeronautical radio navigational system that contains two information related to the runway

32

Which is not a hybrid analog and digital modulation technique?

Continuous-phase modulation

33

A modulation wherein a train of pulses

Delta modulation

34

What is measured in an OMEGA system?

phase

35

For a satellite in orbit, the two parameters must be balanced. These are ___

Gravitational pull and inertia

36

To stabilize a satellite in orbit, this is used

thruster

37

Broadcast station towers are painted __

White and orange

38

The superposition of two TEM wave

mode

39

Mirror-like reflection, a single direction of light when reflected becomes a single outward reflection, this phenomenon is called

specular

40

Camera lens that uses lead oxide

plumbonic

41

What height of an ionized layer is determined from the time interval between the transmission signal and ionospheric echo at vertical incidence?

Virtual height

42

A noise that lowers intensity with frequency

Flicker

43

An extraneous bit is added to the bit stream by a noise source

Glitch

44

Cause of slow rising white “hum bars” in the television

Bad filter

45

In error correction and detection, a process where additional bits are included in the bit stream

hamming code

46

Any subscribed or unsolicited message sent to a user without his/her consent and is sent by PTE or CP

Push message

47

The user tells all callers that the terminal is unavailable

Absent-user service

48

A type of filter that allows below and above frequencies

bandstop

49

Not included component

Synchronizing signal analyzer

50

Which diode is a popular microwave oscillator?

gunn diode

51

Advantage of TWT over Klystron

Wider bandwidth

52

For proper operation, a magnetron must be accompanied by a

permanent magnet

53

In wireless transmission, it is considered as medium range

IEEE 802.11

54

The camera control unit is located____

At the control room console

55

It is used to demagnetize TV sets

degaussing coil

56

Degaussing coil is located__

around the tube face

57

Burst noise is also known as____

Popcorn noise

58

Pulsed radar sets are used to find___

Range and bearing

59

Number of windows in an optical fiber that is available now

111

60

Firewire can connect together up to ____peripherals

63

61

At max sunspot activity, electrons/cm3 in E layer increases by___

50%

62

An antenna that can receive TEM wave polarized in all direction

Helical

63

Least luminous efficiency

Low wattage light bulb

64

Shortening effect of an antenna that makes it appear as if it were 5% longer

End effect

65

An antenna that is mounted on aircrafts

Skin antenna

66

What is the theoretical gain of a Hertzian dipole?

1.76dB

67

If the reflecting surface of a parabolic antenna has accumulated layers of dirt, what is the effect of this?

only negligible effect

68

When ½ of line scanning is used for scanning odd and even lines

Exact interlacing

69

If a mirror cannot be adjusted to view everything, one way to overcome this is by changing to

shorter focal length

70

Typical Speech power

10-1000µW

71

The industry that includes the design, operation and implementation with regards to space and air

Aerospace

72

Multiple access used by DECT

TDMA

73

The area in which no interference-free primary service is given by a licensed Broadcast Station

White area

74

Replaces PDH

SONET

75

Standard Noise temperature in Fahrenheit

62.6

76

First geosynchronous satellite launched in 1963

Syncom II

77

The Angle of I signal(broadcasting-color)

57deg

78

Earth’s base station output power to space

20kW

79

What do you call… 90deg at nose of ship

on starboard beam

80

Measured quantity in Doppler

speed

81

Frequency range of channel 11

198-204 MHz

82

Core diameter of step index multimode fiber

0.2 Angstrom

83

Land mobile service beamwidth

60

84

According to Act 3486, the maximum penalty for a person who commits three offenses are___

P6000 & 6years

85

Luminance(Y) combination

30% red 59% Green 11% Blue

86

NTSC standard sub-carrier frequency (color TV)

3.5795MHz

87

Scintillation occurs at what frequencies

4 and 6GHz

88

For sound carrier not to overlap with higher visual carrier, it must be attenuated by___

13-17 dB

89

Limits the 3 dimension propagation to only a single direction

waveguide

90

Sunspot occurs every how many years

11

91

The part of EM wave that affects matter when it comes in contact

electric field

92

It is the propagation by reflection instead of conduction

waveguide

93

Ear is sensitive at what frequency

1-5kHz

94

Camera output signal without sync____

Non composite video

95

Frequency allocation

96

Number of bits present in 16 combinations

4

97

Solar cells are used for satellite power requirements. During eclipse, ____ batteries are used as back-up

Nicad

98

Photonics are used in very large frequencies, mainly in the range of ____

Terahertz

99

A type of microphone wherein a tiny amplifier is built into it during casting that is called head amplifier

Condenser

100

The part of a fax machine, which consists of rectilinear ribs, determines the position of the scanning lines of record medium

Writing Bar

Complete List of Communications Engineering Coaching Materials


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