Communications Engineering Coaching Materials: Section 5 Module 13

This is the Section 5 Module 13 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 13

This is the Section 5 Module 13 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 13

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Questions

Answers

1

T-1 carrier service has ___digital bit rate

1.544 Mbps

2

The most widely used microwave antenna is a

Horn antenna

3

The wavelength of visible light extends from

400 – 750nm

4

In FM fax, the frequency for black and white are ____ respectively

1500 and 2300 Hz

5

Which of the following is used to measure SWR

Reflectometer

6

What causes splatter interference

Overmodulation

7

A certification issued by the NTC for SRRS radio equipment complying to the SRRS technical standards and specifications, where equipment has already been type approved by the administration whose certification is acceptable and whose process does not require laboratory testing

Type Acceptance certification

8

Using the TE mode, microwave power can only be transmitted in free rectangular guide provided

the wide dimension is greater than one-half of the wavelength in free space

9

Velocity factor of coaxial cables vary from

0.6 to 0.8

10

Refers to the local exchange service area where the telephone density is 1 per 100 inhabitants and shall be based on the telephone density target from the approved National Telephone Development Plan (NTDP), expressed as main station per 100 persons

urban

11

____ theory is deciding between a set of hypotheses when given a collection of imperfect measurements

Estimation

12

What type of connector arrangement where in a costumer may move to another location and still retain the same telephone number

TPS

13

Propagation of electromagnetic waves often called radio-frequency [RF] propagation or simply radio propagation

Free space optics

14

The planned European Satellite Navigation System known as Galileo has ___ no. of constellation satellites

30

15

The most commonly used LNA in satellite transponder is ___ diode

Tunnel

16

It suggests that there is more than one transmission path or method of transmission available a transmitter and a receiver

Diversity

17

The IF bandwidth of a radar receiver is inversely proportional to

Pulse width

18

The chrominance processing circuits can be deactivated when monochrome broadcasts are received by the __

Color killer

19

Which of the following is the color video signal with bandwidth of 1.3 MHz?

I

20

What is the broadcast frequency band used in short-wave broadcasting reception?

HF

21

a source of internal noise

Thermal agitation

22

_____ is an antenna array which is highly directional at right angles to the plane of the array?

Broadside array

23

What is the effect if the gain level being too high for signals entering the modulator?

Distortion and splatter

24

Demodulation of the audio signal is done by the ___

Discriminator

25

For class B-1 FM broadcast stations, the maximum ERP allowed is __ kw with an antenna height limited to __ feet above average terrain

5, 200

26

Infrared technology is used to implement wireless LANs as well as the wireless interface to connect laptops and other portable machines to desktop computer equipped with an infrared transceiver. What wavelength band is used by the typical infrared LANs?

750 and 950 nm

27

The ITU-T recommendation for error detection and correction for asynchronous transmission

V.42

28

A mode that exists in fiber optics when the magnetic field is perpendicular to the direction of propagation but there is a small component of electric field in this direction

TM mode

29

The perigee of the international space station

349km

30

A traditional cable TV channel that belongs to FM band

A-5

31

The three major types of demodulators

Foster-Seely, Quadrature, PLL

32

Most common IF carrier frequency

70Mhz

33

In microwave communication, what concepts may be used to analyze interference by obstacles near the path of a radio beam?

Fresnel zone

34

Rayleigh Scaterring Loss at 8020 nm has a typical value of ___

2.5dB

35

The data rate of information transfer of mobile devices using “Bluetooth”

1 Mbps

36

How many octaves is the frequency range 1 to 8 Mhz?

3

37

In accordance with existing provision of law and the KBP rules and regulations, all station shall actively promote the growth and the development of Filipino music by playing ___ every 4 hours

16

38

Precise scanning and linearity are most important in

single-tube color

39

Which of the following is false?

A fully saturated color is mostly white

40

In an FM-phone signal, what is the term for the maximum deviation from the carrier frequency divided by the maximum audio modulating frequency?

Deviation ratio

41

Snow in a TV picture is a result of

Random noise

42

Time to travel one nautical mile

6.18microseconds

43

microchip that attach of the antenna

Radio frequency identification tag

44

balls that is attach to the antenna wings

To provide corona discharge

45

24 Galileo satellite

4 simultaneous receiver

46

PSK or QAM modulation in fax

Group 3

47

time to transmit 81/2 X 11 in fax

2 minutes

48

advantage of heterodynes

To have high sensitivity and selectivity

49

D.O. 88

Radio station construction permit

50

D.O. 88, DMPST

Amateur, paging in UHF or VHF band

51

paging in cellular

To inform calling from other mobile

52

optical fiber

Maximum distance between repeaters

53

fresnel reflection in optical fiber loss

Return loss

54

where will the loading coil be put

Near the center of vertical reflector

55

resistance loss in glass

292 ohms

56

NTC allocated frequency, as of November

Telemetry

57

stripping effect

Leaky mode

58

maximum bend of a optical fiber

7.5m

59

reverse transmission direction

Line turn around

60

called a fishing rod

Small rod supports the microphone

61

when in crowded or noisy place, it is better to use two ears than covering one

Cocktail party

62

translate ACII, 9,600 bit/ sec

9,600 word/min

63

ILS system

An instrument in aircraft provides two separation

64

spread spectrum fee per 1MHz

P500,000

65

wavelength of infrared

780-950 nm

66

ratio of dummy

1:1

67

allotted for rural

1000 Hz

68

channel 11

211.25

69

channel 44

651.25

70

frequency in ship and coastal

500

71

provides number of new computer

Computer telephone integrator

72

steerable parabolic antenna

Radar lock

73

minimum gain of channel 13

22dB

74

separation in 2GHz

90cm

75

horizontal resolution of broadcasting

428

76

spread spectrum increment

30Hz

77

sonnet sts-I

51.84

78

transfer from laptop to workplace

Cellular digital packet data

79

intensity of sound per 1000Hz

0.0001 picowatts

80

in the IRR, radio transmitter in maritime general calling should observe

Radio silence during silent period

81

optical fiber range from approximately one times ten raised to __ to one times ten raised to __

14, 15

82

resolution of the picture color tv

Frequency response of the video

83

form of single sideband emission when carrier are suppressed

Reduced carrier single band emission

84

three dimension turn to one direction

Waveguide

85

asynchronous bit timing

Syncopated

86

channel 7

178.83

87

electronic method to oppose unwanted noise

Active noise control

88

ITU

Has larger bandwidth and …

89

Referred as a break in optical fiber

Cleave

90

Marconi beacon

75Mhz

91

Bluetooth can support ___ simultaneously in 10m radius

8

92

Travel time in 5km distance

10 minutes

93

Purpose of AFC in FM

To maintain oscillator frequency

94

uses low frequency

OMEGA

95

discriminator as a second detector

Doppler

96

data link layer

To establish and maintain link

97

Multiple sources each converted to a same frequency

TDM

98

Automatic moving of antenna

smart antenna

99

access method in Ethernet

CSMA/CD

100

The OSI layer that manage traffic on the link

Data link layer

Complete List of Communications Engineering Coaching Materials


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