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
# |
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 |
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