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 |
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