Communications Engineering Coaching Materials: Section 1 Module 11

(Last Updated On: December 8, 2017)

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

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Communications Engineering Coaching Materials: Section 1 Module 11
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