Communications Engineering Coaching Materials: Section 1 Module 3

(Last Updated On: December 8, 2017)

Communications Coaching Materials: Section 1 Module 3

This is the Section 1 Module 3 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 3



Given a 63.5µs vertical retrace line, how many complete
horizontal lines are scanned in a vertical flyback?


When a ferrite is subjected to a magnetic field from a
permanent magnet, the electrons spins experience what phenomenon?


What are the two types of network software?

Peer to peer, client server

What do you find at the center of a star topology?

A hub or a switch

What is used to fire a geosynchronous satellite to attain its
final circular geostationary orbit?

Apogee kick motor

What is the flicker nose voltage of a wirewound resistor?

0.01 µV to 0.2µV

What is the flicker noise voltage of a carbon composition?

0.1µV to 2µV

What camera tube uses lead oxide for the photoconductive…?


What is the most common filter used in SSB?

Mechanical filter

What radio transmission process where the message or video
communications are sent to the radio channels that changes frequencies in a
pre-determined order?

Frequency hopping

What is the IMT-2000 maximum data rate for mobile user in a
high speed vehicle?

144 kbps

A licensed and registered ECE can apply for professional
Electronics Engineer if he registered how may years after the effectivity of
RA 9292?

7 years

What is the signal sent y the network to the calling telephone
in order to indicate theat the called telephone is ringing?

Ringback tone

What is the advantage of optical fiber made up of plastic?

Inexpensive and more flexible

ICT means

Information and Communication Technology

The maximum radiation from any electronic equipment should not
exceed _______ mr per week?

100 mr

Depending on the terrain a microwave system uses line of sight
propagation and may require repeater approximately every ______

40 km

A type of card with embedded integrated circuit with functions
that can be used in storing subscriber information in a PCS system

Smart card

What is the technique employed in networks to avoid accidental
flags (adding bits)?

Bit stuffing

What law created the MTRCB

P.D 1986

What is another name for pink noise?

Flicker noise

What is the frequency separation between the forward channel
and the reverse channel in a cellular communication system?

45 MHz

What is the tone produced by a sound source other than the
fundamental tone?


What is the digital audio compression that substitutes MP3

Dolby AC-3

In the operation and maintenance of cable TV system, you need

Duly registered ECE

What is the amount of sound attenuation offered by the wall,
ceiling and floor?

Transmission loss

What is the typical range of velocity factor in a coaxial

0.6 to 0.8

What devices are inserted into a telephone channel if the total
net loss of the trunk circuit exceeds about 2.5 dB?

Echo suppressors

The orbits of the GPS satellites are nearly circular with
inclination angles of ____ degrees relative to the equator

55 degrees

GPS satellite separation

60 degrees

Why is geostationary satellite not stationary for region near
poles of the earth?

The angle of inclination is too low for
these regions

What is the maximum bit rate for fiber optic cable?

10 Gig per sec

Which modulation is the most noise resistant?

PCM (pulse code modulation)

What is the science of measuring of light visible to human


What is the center impedance of a half wave antenna?

73 ohms

What is the increase in the network capacity that can be
achieved by 3G wireless system?


What is the major benefit of DSB and SSB?

Higher power in the sidebands

How much is the fine of unauthorized servicing of mobile

5000 Pesos per unit

Binary pattern of ones and zeros arranged in random?

Pseudorandom code

If an audio signal is lost on a high frequency, what can be
added to it to flatten the response?


A network using microwaves for two-way transmission of
telephony, television, and high-speed data

Local Multipoint Distribution System (LMDS)

What is the speed of the geostationary satellite?

6879 statute miles per hour

What is the technique used in MPEG 2 compression?

Discrete Cosine Transform

What refers to the ability of the FM receiver to receive the
stronger of the two signals and ignoring the weaker one?

Capture effect

What is the primary advantage of microwave?

Wide bandwidth availability

What class of mobile phone whose maximum power output level is
specified as the ERP of 2dB watts? (1.6 Watts)

Class 2 or transportable phone

How many different symbols are possible outputs of a 16QAM


What refers to the reflection at the interface of two optical
materials which depends on their refractive index and the angle in which
light strikes the interface

Frenzel reflection

What type of message in radio control channel in cellular
systems tells a particular mobile telephone that a call is to be received?


What is the modulation method used in European cordless


What do you call the calls which cannot be completed because
the central office or PBX switching capacity was full at the time the call
was attempted?

Blocked calls

What layer in the OSI is responsible for transmitting bits in
the communications channel?

Physical layer

What is the ratio of the speed of light in air to the speed of
light in another medium?

Index of refraction

The memory storage in cellular phones for the telephone number
to be used are stored in what is known as

MPEG 1 (Motion Pictures Experts Group)

What types of microphone produce low 2 outputs?

Dynamic, ribbon, carbon

What is the speech coding rate of GSM for cellular system?

13 kbps

What is the bandwidth of GSM?

200 kHz

What formula is used in determining the overall noise
performance of a receiver of multiple stages of RF amplification?

Friis’ formula

What is the lowest layer in the OSI model that deals with
matters such as voltage and current levels?

Physical layer

Brightness variations in color information are in what signal?

Y (luminance)

What is the modulation and multiplexing technique that
distribute signals and its sidebands over a very wide bandwidth

Spread spectrum

What is the operating frequency of telephone quality analog
voice signals?

300 Hz- 3 kHz

What scrambling method is used in compact disc digital audio
system to ensure that enough transitions between zero’s and one’s can take
easily clocking information?

8 to 14 modulation

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

More than 2 mbps

What is the maximum number of years of a certificate authority
issued by the NTC to the cable TV operator?

15 years

At what frequency does a magnetron in a microwave oven

2.45 GHz

What order of the NTC which provides implementing guidelines
on the grant of mobile phone dealers permit? (MPDP)

Office Order 87-08-2004

What NTC memorandum circular provides additional rules and
regulations on the purchase, sales, lease/rentals of mobile phones?

MC 08-08-2004

The electronic technician, as defined by MPSCT, implementation
guidelines must be a graduate of an electronic technician course and should
have completed formal training in repairing, servicing, and maintenance
conducted by mobile phone manufacturer and/or training center that are truly
accredited ____


Helical antenna is often used as a typical satellite tracking
because of

Faraday effect

What is the main disadvantage of fiber optic cable made of


A comb filter is used to ________

To cancel chroma crosstalk

In tv, which controls the phase angle of demodulated color
video signal


In general typical range of frequency that troposcatter wave
propagation is found to be effective

350 MHz to 10 GHz

What modulation is used in Enhance Data rate for GSM Evolution


Where should MBSCP or MDPD file their application?

NTC regional office

If public key is used to encrypt the message, what is required
to decipher it?

Private key

What do you call a card that comes with an 800/888 number that
the card owner dials to reach a network that allows him to dial anywhere he

Pre-paid phone card

Registered electronics engineer who is not a member of an
accredited professional organization must register within ____ years after
the effectivity of RA 9292?


What is IMT 2000 maximum data rate for pedestrian mobile users
and for slow moving vehicles?

384 kbps

What is the basic component of a satellite?


Refers to many major wireless manufacturer that have combined
to create de facto standards in creating this content

Wireless application protocol

What is the frequency of the middle C

242 Hz

What is the frequency of 1 octave above middle C

542 Hz

Which of the following is not a porous absorber

Membrane absorber

The time that a synthesizer remains at a frequency called

Dwell time

To be a member of the board, an applicant should be in active
practice of electronics engineering in how many years before promotion?

10 years

Complete List of Communications Engineering Coaching Materials

Communications Engineering Coaching Materials: Section 1 Module 3
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