Communications Engineering Coaching Materials: Section 1 Module 4

(Last Updated On: December 8, 2017)

Communications Coaching Materials: Section 1 Module 4

This is the Section 1 Module 4 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 4



What is the maximum VF tone that may be fed to a voice signal

+6 dB

What is the maximum power of the Class 1 analog mobile phone

600 mW

The average voltage value of the 3.58MHz modulated chrominance
signal in TV receivers is___________

brightness of the color

How many lines does a standard NTSC has?


F3 emission means carrier frequency is modulated by _______


The aeronautical radio navigation land station that provides
direct bearing on that station from an aircraft is known as _____________

range station

What is the frequency tolerance for aircraft station employing
SSB transmission?

20 ppm

The range of the human hearing can form how many octaves


What results in the luminance components interfering in the
color signal, it occurs whenever there is diagonal detail on that picture and
gets worse with motion


How many horizontal lines are blanked out in the frame of TV
receivers by V blanking


What would be the bandwidth of an AF filter for CW

500 to
1000 Hz

A superjumbo group has how many voice band channel


A characteristic of the modulating signal that is proportional
with the amount of frequency deviation from the carrier center frequency in


“?” requires that the amplitude of each sample be converted
into ______


In the single tube class C amplifier why is the “?” modulated
envelop that made up of varying amplitude dc pulses

Because of

What is the data transmission rate of the North American AMPS

10 kbps

The split pair is used by IBM token ring network that operates
at either

4 or 16

In acoustics, what do you call the present combination of


What is a system where cables and wires are placed within the
ceiling and poked up in the resistance floor structured to office or the room

Poke probe

3G wireless system was introduced in what year


In telephone system, what traffic model is based on the
assumption that calls are not immediately satisfied that the first attempt
are held in the system until it is satisfied


What is the maximum VF tone that may be fed in the telephone

0 VU

What type of modulation is produced by sampling an analog


What is the number of lines scan per frame in the raster on
the picture tube


What is the velocity of the geostationary satellite in orbit

statute mph

Which navigation does not have global range


What refers to the system where an aircraft’s navigation aid
measures the time interval between an interrogatory pulse and the reply from
the radar from a radar beacon

(Distance Measuring Equipment)

What is the accuracy of LORAN C long range hyperbolic radio
navigation system

¼ of a
mile absolute & >100ft

What is the main advantage of GPRS

It doesn’t
require a connection

How many TV fields are recorded on one slant track of tape


What frequency sharing technique uses highly directional spot
beam antennas to prevent interference between stations of the same frequency.


What is used to produce low power microwave oscillators


What is the variation of the discriminator which greatly
reduces sensitivity to amplitude variations and causes a 50% reduction in
output voltage


Under the revised regulation governing cable TV systems in the
Philippines regular duplicated by the network programming by one or more
station in a week during the hours of 6 to 11 PM local time to a total of how
many hours or more?

14 hours

What is the minimum rejection of a CATV system

60 dB

In CATV system what is sound section isolation

40 dB

In CATV system what is the RF output terminal match

16 dB

In the NTSC regulation, how much is the fine for the MPSC
operating without valid NTC permit


What is the term for the ratio for the luminous power to the
radiant power in the sample of light and expressed in lumens per watt of
gradient energy


What do you call a special microwave coaxial cable which is
made of hard tubing rather that wire with an insulating cover that can be
used on the lower microwave band

Hard line

Which of the following are antennas made with micro strip on


Which coaxial connector is of more complex and expensive that
do a better job in maintaining the electrical char of the cable through


What is the dielectric constant of polyethylene insulator


How is tapped single button microphone cleared?


What helps protect fiber against degradation cause by moisture


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

Along the

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

4 times

What filter may be connected between a CB transmitter and its

Low pass

When real time communication is required the only way to
address the second fragment is to use a ____ containing more that 1 satellite


What is the common usage of single button microphones


What is the advantage of using hub over direct interconnection
to all the terminals

Its easy to move computers

A broadcast station is transmitting but not modulating, what
is heard in a receiver tuned to its frequency


A network using microwave for two way transmission of
telephony and in high speed data

Multipoint Distribution System (LMDS)

In TV system, if the 3.58MHz C amp in the receiver does not
operate, the result will be __________?

No color

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


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


What is the max efficiency of class C amp?


What is the max recommended cable length of RS232C cable?

50 feet

What is the typical value of line turn around?

1.5 ms

Which pulse in the V blanking corresponds to 3H lines wide?

V sync

What refers to the nonlinear effect that occurs at low power
as low as 3mw in single mode fiber and takes the form of a light shifter
slightly in frequency from the original light wave


In wide area networks what routing technique requires each
node to take the incoming packet and retransmit it onto every outgoing line?


For analog dram scanners what type of modulation is used after
the receive light has been converted into electrical energy?


What is the most commonly used transmission line?

Coax cable
or line

In what 2 systems in the voice transmitter can speech
processing be used?

AF and RF

What can be determined about a transformer by an ohmmeter?

continuity, shorts to case and interwinding shorts

Why is a matched line indistinguishable from an infinitely
long line as seen from the source?

Since no
energy is reflected from the match load, so for the source it appears as if
energy is put into the line continuous to move down the line forever

What type of circuit produces even order harmonics?


What is the designation of SSB with full carrier?


What is the achievable data rate of the 3G cellular system?

More than

What is the time period for a single time slot in GSM TDMA


What packets switch data technique is used with the GSM


What do you call the process by analog signal are transmitted
by converting them into a series of pulses whose amplitude is approximately
the shape of the analog signal


In Ethernet LAN, what situation arises when two or more
terminals try to transmit in the network at the same time?


What do you call the interval which it’s an integer or whole
fraction ratio


What is defined as the ratio of frequency of two pure tones?


What do you call the first note of the musical scale?

Root note

In what year will the FCC face the analog broadcasting?


Which of the following is or are parts of the network
interface card?

Both BNC
and RJ49 connectors

Which of the ff wavelengths where
absorption of electromagnetic waves becomes peak due to vibrational resonance
in the water vapor molecule

1.35cm and

What class of mobile phone has a maximum power level specified
as ERP of -2dBW or 600mW

Class III
(mobile phone)

What refers to a series of tones that sounds good when used in


An MPD shop properly identifies its business and location by
posting conspicuously at the entrance of its premises a sign board, what are
the dimensions of the sign board?

50cm x

Electronic technician as defined by the MPSCP implementing
guidelines should be a graduate of an electronic technician course and should
have completed a formal training course in the repairs, servicing and
maintenance of mobile phones conducted by mobile phone manufacturers and or
training service center duly accredited by _________


Under RA 9292, one qualification to be a member of the board
is being a citizen and resident in the Philippines for at least how many

5 years

What technique is employed by the transmitter to avoid
accidental flags


If two signal are in quadrature, what tie the phase relation

90 degrees

What do you call a type of communications by propagation is
primarily by the direct or space wave which travels in straight line at
frequency above 30Mhz


What feature of SONET allows data spin with different paths to
be sync


What is a specialized transformer that allows telephone voice
signals to travel in both directions simultaneously in a single twisted pair


Cable TV companies collect signals and programs from many
sources in a facility called ____________

Head end

Refers to the transmission of multiple TV signals which are
frequency multiplexed on a single cable to be used in lieu of over the air
signal trans

Cable TV

What is the other name of super refraction


What is the reason why tropospheric ducting not used very much
in practical communication systems?

Because it
is not reliable

What is the function of a hybrid in the telephone handset

mic signal in phones

When the called telephone is ringing, the CO sends a pulse AC
voltage to the calling telephone. What is that signal called?

Ringback signal

What unit refers to radiation other than x-rays which will
have an absorption equal to 1 roentgens

Rep –
roentgen equivalent physical

Different sources of radiation have different effect which are
related to x-rays by a number which is referred to as the ______

Rbe – roentgen biological

Complete List of Communications Engineering Coaching Materials

Communications Engineering Coaching Materials: Section 1 Module 4
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