Communications Engineering Coaching Materials: Section 1 Module 11

This is the Section 1 Module 11 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 1 Module 11

This is the Section 1 Module 11 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 1 Module 11

ITEM

QUESTIONS

ANSWERS

76

What technique is employed by the transmitter to avoid accidental flags?

Bit Stuffing

77

What refers to the emphasizing of low level signals and compressing of high level signals?

Companding

78

Why “downtilt” is used in cellular base stations?

Because it can be used to reduce the range of a base station to reduce interference

79

In TV system, if the 3.58 MHz C amplifier in the receiver does not operate the result will be____

No color

80

What filter may be connected between CB transmitter and its antenna?

Low Pass Filter

81

How is fiber grating produced?

By illuminating the fiver with ultraviolet light

82

What types of microphone have high Z output?

Crystal, electret and condenser

83

How is a packaged single button microphone cleared

Jarred

84

What are pulses that retain their shapes as they pass through optical fibers?

Solitons

85

What is the measure of the sensitivity o the detector to light?

Responsitivity

86

What refers to the series of tones that sound good when used

Musical scale

87

A TV receiver design that uses mixing between the picture and sound carriers to generate the sound IF. What do you call this sound?

Intercarrier sound

88

What microphones are predominantly used in Aviation services

Dynamic microphones

89

In TV, what is the hue of a 90 degree leading sync burst

Cyan

90

A 100 Mbps LAN signaling standard intended for use in fiber optics but also used with coaxial cables

Fiber Distribution Data Interference (FDDI)

91

In IMT 2000, what does 2000 refer to?

Both the implementing date (year 2000) and operating frequency (2000 MHz)

92

A system that allows users to access documents from widely separated sources on the internet using a common interface

World Wide Web

93

What do you call the perceptible sound repetition?

Echo

94

What is the reason why point contact and Schottky or hot carrier diodes are widely used as mixers in microwave equipment

They have low capacitance and inductance

95

What do you call the area that lies between the outer limit of the ground wave range and the inner edge of energy returned form the ionosphere?

Skip Zone

96

What principle is employed in cellular telephony to allow simultaneous transmission and reception without the need to push to talk?

Frequency duplex

97

What harmonics are in a square wave

Odd harmonics

98

Which of the following is not a bit oriented protocol?

BISYNC

99

The rbe dose is expressed in __________?

Rems (roentgen equivalent man) or rebs (roentgen equivalent biological)

100

In TV, special effects and production switching are done by the

Special Effects Groups (SEG)

101

What is the primary application of fiber optic communication?

Long-distance telephone system

102

A point on a line between the earth’s center and an observer located farther from the earth’s center than the point is called

Nadir

103

What is the noise reduction effect that occurs with strong FM signals

Threshold effect

104

What junction device can operate as an oscillator or amplifier by means of avalanche breakdown?

IMPATT diode

105

Which of the following is not an acoustical signal defect to be avoided in acoustical signals?

Reverberation

106

What waveguide-like device that acts like a high Q parallel resonant circuit?

Cavity resonator

107

What modulation method is used by GPRS system

GMSK

108

What helps protect fivers against degradation caused by moisture

Cabling

109

For an angle of incidence equal to the critical angle, the light will be refracted

Along the normal

110

If a rocket contains more than one satellite, the smaller satellite that will be launched after the main satellite is called

Secondary payload

111

What do you call an interval which … integer ratio or a whole fraction ratio?

Octave interval

112

What is the hue color sync phase?

Yellow green

113

What is any tone produced by a sound source in addition to the fundamental tone

Overtone

114

In communications system, the total system noise in the absence of information transmission is called

Background noise

115

The average voltage value of the 3.58 MHz modulated chrominance signal in TV receiver is___

The brightness of the color

116

In TV system, which signal has information for 1.3 MHZ bandwidth?

I signal

117

A lens has an 8-cm focal length and a 4-cm diameter. What is its F rating?

2

118

How much more feed point impedance does a folded dipole have than a normal dipole?

4 times

119

The electronic serial number (ESN) assigned to the mobile phone at the factory consists of _____

32 bits

120

How many scanning lines does a standard NTSC have?

525 lines

121

Solid state neodymium can generate high power at

1.3 micro seconds

122

A radar mile is the time required for a radar pulse to travel 1 mile to an object and return to the receiver. 1 radar nautical mile is equivalent to ____ microseconds

12.4 micro seconds

123

How long does a repeater transmit a mobile signal drop out?

1-5 seconds

124

What is the orbital period of each GPS constellation?

12 hours

125

What loudness level in which permanent damage to hearing is possible?

150 dB

126

What is the minimum ratio of visual signal level to system noise, and of visual level to any undesired co-channel TV signal operating on proper offset performance?

36 dB

127

In CATV, what is the noise figure for mid, high and super band channels?

6 dB or better

128

In CATV system, what is the noise figure for sub and 10- band channels?

5 dB or better

129

What is the maximum height above average terrain for a class B FM station?

500 ft

130

What is the maximum recommended cable length for an RS 232C cable

50 ft

131

LEO satellites orbit the earth at an altitude less than how many kilometers?

1500 km

132

What is the end impedance of a half wave dipole

2500 ohms

133

What is the typical loudness level of a watch ticking

120 Phons

134

In FM broadcasting, what is the highest required modulating frequency?

16 kHz

135

What is the maximum deviation of cellular radios that use FM?

±12 kHz

136

What is the frequency used to signal handoffs to another cell and the termination of the cell in cellular communications?

10 kHz

137

At what frequency does magnetron microwave oven operates?

2.45 GHz

138

How wide are GSM channels

200 kHz

139

What is the frequency of middle C?

262 Hz

140

In general, what frequency range does a troposcatter wave propagation will be effective?

350 MHz to 10 GHz

141

What would be the bandwidth of … filter for voice and SSB

3 kHz

142

What is the conduction angle of Class C amplifier?

Less than 180 degrees

143

What is the letter number designation of AM voice or music emission?

A3

144

What protocol is very poplar system for defining and switching data packets on computer networks?

x.25

145

When was the first commercial system operated?

October 13, 1983

146

What class of mobile phone has a maximum power level specified as effective radiated power (ERP) of -2 dBW (600 mW)

Class 3 (portable phone)

147

What class of mobile phone has a maximum power level specified as effective radiated power (ERP) of 1.68W

Class 2

148

What class of mobile phone has a maximum power level specified as effective radiated power (ERP) of 3W

Class 1

Complete List of Communications Engineering Coaching Materials


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