EST COACHING

..Parts of superheterodyne responsible for bandpass of the receiver

Ans. IF amplifier

*What type of 2nd detector is used for AM?

Ans. Diode

FM detectors not used in mobiles

Ans. Balanced modulator

Tunes the receiver to different stations

Ans. Local oscillator

In FM receiver which circuit removes amplitude variations?

Ans. Limiter

A type of devices noise whose intensity decreases with frequency

Ans. Flicker

Industrial noise frequency

Ans. 15-160 MHz

Frequency for the pilot subcarrier for commercial stereo FM

Ans. 19 kHz

In video system, what determines the maximum number of vertical picture elements?

Ans. No. of lines on the screen

*What does aspect ratio mean?

Ans. Ratio of screen height to its width

How many oscillators does a black and white TV contain?

Ans. 2

How many electron beams leave the electron gun on a single-gun CRT?

Ans. 3

In a single-gun color CRT, what electron beam travels straight through the tube?

Ans. Green

In a TV picture tube, what is the purpose of large picture tube voltage?

Ans. Attracts electrons toward the face of the tube

How many horizontal lines are used to develop a TV raster in NTSC standard?/ Number of lines
scanned per frame in the raster on a picture tube
In TV, time allocated per horizontal retrace

Ans. 525

Which band channel 14 of TV channel belongs?

Ans. UHF

What do you call the combining circuit used in TV?

Ans. Matrix

A type of microphone which has a permanent magnet

Ans. Ribbon

What determines the purity received colors?

Ans. Q & I amplitude

What would be produced by weak blue, weak green, weak red on color CRT?

Ans. Gray

The typical output voltage from a magnetic microphone

Ans. 1 mV

Modulation index of AM wave is changed from 0 to 1, the transmitter power is

Ans. Increased by 50%

Method generating SSB signal that utilizes one balanced modulator circuit

Ans. Filter method

What is the lowest number of sections required by communication receivers?

Ans. 4

Connecting a headset directly across the tuner in a simple AM radio receiver

Ans. Will not produce sound in the headset

Which of the following is not a continuous wave modulation?

Ans. PCM

*What are the letter, number designations of carrier and one SB?

Ans. H3E

What determines the selectivity of a receiver?

Ans. The bandwidth of the tuned circuit

How many mixers are in an SSB receiver?

Ans. 2

What is the purpose of AFC in an FM receiver?

Ans. To help maintain a steady LO frequency

What circuit accompanies a mixer?

Ans. Local oscillator

Not a class of laser radiation

Ans. Class X

Optical fiber with smallest beamwidth

Ans. Glass fiber core

Fiber optic cable operates near

Ans. 800 THz

Pitch in sound

Ans. Color in light

Min illumination recommended for reading

Ans. 8000 Ix or 800 lux (alin dito?)

Photophone

Ans. First device voice using light

Part of body most sensitive to laser

Ans. Eyes & skin

Infrared range

Ans. 700-1200 nm

QAM

Ans. G3 fax

Echo completely out of control

Ans. Singing

Visible light range

Ans. 400-750 nm

Standard test tone

Ans. 1 mW

Ans. 10.2 sec

EST COACHING
The perceptible repetition of sound is called ___

Ans. Echo

What resistor has a typical flicker noise voltage range of 0.02 to 0.20 microvolts?

Ans. Metal film

Transmitter power output in single sideband operation is expressed in terms of ___

Ans. PEP

Noise when measured across tip and ring terminals of a network shall be ___ dBrncO

Ans. 15

How many groups are there in (CCITTS FDM hierarchy) a supermastergroup?

Ans. 75

A fiber optic light electron PIN diode is lightly doped in ___ material

Ans. Intrinsic

The dominant loss mechanisms in silica fiber used in fiber optics

Ans. Absorption and Rayleigh scattering loss

* how many voice band channels are there in a DS-2 digital signal hierarchy for TDM signals?

Ans. 96

*Another name for optical density

Ans. Radiant flux

When a plan EM wave propagates in free space, it travels as ___

Ans. TEM

Unit used to indicate the loudness of tone compared to the intensity of 1000 Hz tone

Ans. Phon

Unit of pitch

Ans. Mel

Antenna utilizing the ground as part of its resonant circuit

Ans. Marconi

Antenna complete in itself and capable of self oscillation

Ans. Hertz

Flicker noise in radio communications is also referred to as ___

Ans. Pink noise

The aspect ratio for HDTV

Ans. 16:9

In sound recording, a type of cassette tape known as the chrome tape is the type ___

Ans. 2

*The meaning of MP3

Ans. Motion picture experts group 1, audio layer 3

The access method of Ethernet is ___

Ans. CSMA/CD

How many voice channels are there in master group?

Ans. 600

Among the connectors the transmission lines for coax, which is the least expensive as is widely
used for CATV, VCRS, and TV sets

Ans. F-7 type

What is a wavelength of a violet ray of light in micron (4000 Angstrom)?

Ans. 0.4

Among visible light rays of blue, green, yellow, and orange which has the longest wavelength?

Ans. Orange

Which of the following does not fall under the optical spectrum?

Ans. Gamma rays

One of this falls within the visible frequency range

Ans. 0.4 to 0.8

What is the infrared range used for fiber optics in Angstrom?

Ans. 7,000 to 12,000

The bending of light rays due to change in velocity as a result of traveling from one medium to
another

Ans. Refraction

What is the primary specification of a fiber cable usually expressed as the loss in dB/km?

Ans. Attenuation

What is the most widely used light generator in a fiber optic system?

Ans. Injection laser diode

Presently, the average maximum distance between repeaters in a fiber optic system is between
___

Ans. 10-30 km

Fiber optics performance is usually indicated by ___

Ans. Product of bit rate and distance

*In a telephone system, what traffic model is based on the assumption that calls are not held in
the system until it is satisfied?

Ans. Erlang C

What is the new access method used in 3G mobile telephony?

Ans. WCDMA

Frequency of unmodulated carrier of an FM

Ans. Rest frequency

Amount of power lost in device due to the path of energy flow

Ans. Insertion loss

What determines station that will be selected by a tuner?

Ans. Resonant frequency of tuner

Periodic waveform consists of odd harmonics

Ans. Square wave

What happens to a spectrum of repetitive pulse in the pulse width decrease?

Ans. More harmonic of the same phase

Keyed AGC is AGC that

Ans. Is used in TV receivers

Class of bias that produces least harmonics

Ans. Class A

Device used to make modulated visible

Ans. Oscilloscope

EST COACHING
What is the frequency of the standard test tone conducted on audio equipment?

Ans. 1 kHz

A light wave is 8000 Angstrom long, what is the wavelength in nanometer?

Ans. 800

Low contrast picture in which white seems flat and lacking in detail suggests ___

Ans. low beam current

Camera tube that has minimum lag

Ans. Plumbicon

Gamma of picture tube of TV

Ans. 2.2

Heater voltage of TV receiver picture tube

Ans. 6.3 V

In a frequency synthesizer, smallest amount which output frequency can be changed

Ans. resolution

Suppressed carrier frequency of channel 4 of a group using FDM telephony

Ans. 96 kHz

What determines the bandwidth of a transmitted signal?

Ans. highest frequency component of the modulating signal

What happens in standard AM transmission, no modulating signal is being transmitted?

Ans. there are no sidebands

B83 form of modulation is also known as ___

Ans. Independent Sideband Emission

Modulating 2 waves of the same frequency but with ___ phase difference is equivalent to
modulating both amplitude and phase of the same carrier

Ans. 90 degrees

Colloquial term describes additional side frequencies produced by overmodulation or distortion in

AM

Ans. splatter

Color with most luminance

Ans. yellow

Second IF value for color in TV receiver in any station

Ans. 3.58 MHz

If 3.58 MHz class C amplifier in a tv receiver is not working

Ans. no color

Width of H-blanking pulse

Ans. 10.2 s

Intermediate power amplifier (IPA) transmitter is also known as ___

Ans. Driver

Three major types of demodulators

Ans. Foster-Seeley, Quadrature, PLL

What determines the resolutions of the picture in a TV receiver?

Ans. The frequency response of the video signal

Antenna whose technical equivalent is /4 line which is open-circuited

Ans. Dipole

Marconi type of antenna is a grounded ___ vertical antenna

Ans. /4

The time when the FET is on is called ___

Ans. Acquisition

In data communication employing FSK, baud rate is ___ of bit rate

Ans. Equal

Grounding system of an AM broadcast tower radiator may be improved using radial wires
known as ___

Ans. Counterpoise

Greater p-p amplitude

Ans. Saturation

Audible sound that can be detected by human ear are in range ___

Ans. 16 Hz 16 kHz

Pre modulation system most noise resistant

Ans. FM

Used to suppress carrier in single sideband transmitters

Ans. Balance modulator

Theoretical (mathematical) expectation of the error rate for a given system

Ans. Probability of error

Most reliable scheme for error detection

Ans. CRC

Multiple access system used in satellite communications most use today

Ans. TDMA

A weak horizontal amplifier in a color TV receiver can cause ___

Ans. Insufficient width of the picture

The protocol that uses the checksum method of error detection is the ___ protocol

Ans. XMODEM

*What is the current digital video specification applying video compression?

Ans. MPEG-4

The term used for rf radiation damage to cells of reproductive tissues

Ans. Genetic

The modulation system employed by the European Cordless Telephone

Ans. GFSK

The propagation velocity of longitudinal waves depends on the ___ of the medium

Ans. Compressibility

An MPEG-4 based video compression technology uses a radio format known as ___

Ans. DivX

*Which of the standards given below is for terrestrial digital TV transmission?

Ans. 8-V.58 (8- VSB?)

In what acoustical scale are all intervals exactly constant?

Ans. Diatonic

In FDM, with an L600 master group, what is the carrier frequency of super group 10?

Ans. 3100

EST COACHING
In April 2002, the IEEE published their 802.16 standard for broadband wireless access (BWA),
more commonly known as ___

Ans. WIMAX

In fiber optics, the main disadvantage of plastic over glass fiber is ___

Ans. High attenuation

Most densed of all the ionized layer of the ionosphere

Ans. F2

/2 antenna radiator when used at 150 MHz approximate length

Ans. 1 meter

Frequency band used with submarines

Ans. ELF

Also known as Mogul-Delinger fadeout

Ans. Sudden ionospheric disturbance

Super high frequency

Ans. 3-30 GHz

Present only during daytime

Ans. D layer

The velocity of radio waves ___ as it passes from air to the ionosphere

Ans. Increases

Ducts often are formed over

Ans. Bodies of water

Type of laser used for fiber optic communications

Ans. Semiconductor laser

Range of frequency used for fiber optic system is

Ans. 100-1000 THz

The statement Incoming light is partially absorbed and partially transmitted equally in all
directions is known as ___

Ans. The Lambertian reflection

In broadband ISDN (B-ISDN), the channel rate of H21 is ___

Ans. 32.786 Mbps

The digital rate for T1 carrier service is ___

Ans. 1.544 Mbps

Ethernet is a baseband system using CSMA/CD operating at ___

Ans. 10 Mbps

Synchronous modems cost more than asynchronous modems because ___

Ans. They must contain clock recovery circuits

Which OSI layer has inter-host communication?

Ans. Session layer

In data communications, the T in 10 Base T normally represents ___

Ans. The type of cable used

An array of simple dipoles fed in phase and having a radiation pattern whose maximum
directivity is along the axis normal to the plane of the array

Ans. Broadside array

A microwave antenna formed from a circular waveguide

Ans. Conical horn antenna

Technique that allows correction of data of the receiver

Ans. FEC

System where transmitted receive clock free-run at approximately the same speed

Ans. Asynchronous

Layer that accepts and structures the messages for the application

Ans. Presentation

Manages traffic on the link

Ans. Data link

Type of antenna capable of transmitting (receiving) a TEM wave polarized in any direction

Ans. Helical antenna

A region within the influence of the induction field of an antenna

Ans. Near field

Layers task with the end-to-end accountability through a network

Ans. Network

Modern digital systems use a ___ to demodulate a PAM signal

Ans. LPF

*A signal which varies between 3 levels

Ans. Bipolar code

Based on the representing most commonly used characters with the fewest number of bits

Ans. Huffman encoding

Typical SNA topology is ___

Ans. Hierarchal topology

Typical PBX configuration

Ans. Star topology

Which of the following achieves code transparency with frequency?

Ans. Bit-oriented protocol

Data transfer uses handshaking principle

Ans. Synchronous data transfer

Band most suitable for SSB generation

Ans. 3-30 MHz

What is the color subcarrier for channel 5?

Ans. 80.83 MHz

Which stages in broadcast transmitter are normally class C?

Ans. Modulated amplifier

*Term in asynchronous transfer mode (ATM) system to describe a byte

Ans. Octet

Room where boundaries absorb effectively all incident sound

Ans. Anechoic room

Ability of sound device whose instantaneous waveform to that of sine wave

Ans. Pure tone

EST COACHING
Persistence of sound in an space of multiple reflection or scattering for the sound source has
stopped?

Ans. Reverberation

Horizontal scanning time for 1 pixel

Ans. 0.125 s

Ans. 0.25 s

For 2 pixels

For 12.5 pixels

Ans. 1.56 s

Video heads rotate

Ans. Writing speed

The part that rotates to meter out the tape at constant speed

Ans. Capstan

Bluetooth standard

Ans. 802.15

GPRS uplink data rate

Ans. 14 kbps

Send or receive

Ans. Session

Method of encoding audio signal used in US standard 1.544 Mbps 24 channel PCM system

Ans. Mu Law

Achieves code transparency with ring

Ans. Bit oriented protocol

Topology which is relatively immune to bottleneck

Ans. Mesh topology

Antenna /10 long

Ans. Elementary doublet

Two main characteristics of sound waves

Ans. Pitch and loudness

RS 232C

Ans. 25 pins

Bridge

Ans. Physical and data link

In order to avoid reflections, the load impedance used to terminate RG 62 is compared as ___
ohms

Ans. 93

*What do you call a text code that makes use of 16-bit long code words

Ans. Unicode

*The law governing the regulation of radio communications in the Philippines is ___

Ans. Act 3846

A type of feedback determined by the balancing network and permits the talker to hear his/her
own voice.

ANS. SIDETONE

Which exchange is used to connect between central offices when a direct trunk is not available?

ANS. TANDEM

What component in the telephone set has the primary functions of compensating for the local
loop length?

ANS VARISTOR

What type of receiver is most commonly used in a conventional telephone handset?

ANS. ELECTROMAGNETIC

Which component in the telephone set has the primary function of interfacing the handset to the
local loop?

ANS. INDUCTION COIL

Speakerphones operates in ___ mode

ANS: HALF-DUPLEX

Pulse dialing occurs at a rate of ___ pulses per second

ANS: 10

Pulses dialers must ___ the receiver in the set while dialing

ANS: MUTE

The equation fs=2BW or fs=2fa is called the ___

ANS: NYQUIST CRITERION

High speed transmission systems for carrying data over twisted copper pairs are known as ___
systems

ANS: DIGITAL SUBSCRIBER LINE (DSL)

The average level of the luminance within an active picture. Usually expressed as a percentage of
reference white level

ANS: AVERAGE PICTURE LEVEL (APL)

The designer of central office equipment should maintain the ___ between the subscriber and
central office

ANS: STANDARD INTERFACE

SLIC stands for

ANS: SUBSCRIBER LINE INERFACE CARD

One section in a D1 channel band handles ___ voice channels

ANS: 24

The most popular plug for RG59U coaxial cable is the

ANS: F CONNECTOR

How many unique tones are used for the 12-key dual-tone multifrequency keypad?

ANS: 7

A booth in a TV studio for observers, such as sponsors and VIPs.

ANS: FISHBOWL

What does a microprocessor require in order to work with a telephone circuit?

ANS: ROM AND RAM

Protocols may be ___ oriented.

ANS: BIT ORIENTED, BYTE ORIENTED AND CHARACTER

ORIENTED

EST COACHING
A 35-mm frame of film that measures 36 x 24 mm has an aspect ration of ___.

ANS: 3:2

In a low-level AM system, amplifiers following the modulated stage must be __ devices.

ANS: LINEAR DEVICES

The combining of two sound signals into a composite recording is called __.

ANS: DUBBING

If the grade of service of a telephone system indicated P of 0.05, what does it mean?

ANS. LOST CALLS OF 5%

A mobile receiver experiences dead areas of reception as a result of

SHADING OF THE RF SIGNALS BY HILLS AND TREES

A set of charts used in color TV to verify hue, brilliance and chroma.

ANS. MUNSELL COLOR SCALE

At very high frequencies, transmission lines acts as ___.

ANS. ANTENNAS

The total cost of a radio or TV program production, or sponsorship.

ANS. NUT

What causes attenuation present in a waveguide?

ANS. WALLS OF THE GUIDE

What is BFO in SSB receiver called?

ANS. CARRIER OSCILLATOR

What is the current digital video specification applying video compression?

ANS. MPEG-4

What is the unit for median field strength of TV broadcast station?

ANS. dBu

RG59u coaxial cable has an impedance of __ ohms.

ANS. 75

What was the most significant contribution of the satellite named Score?

ANS. IT WAS THE FIRST SATELLITE TO TRANSMIT MESSAGE

The rule of thumb states that one should be seated at least __ ft. from a 31 screen.

ANS. 7

In color perception, the degree to which the light energy is confined to a narrow frequency band. It
is thus the converse of the extent to which the color is diluted with white light.

ANS. SATURATION

In TV, blurring of the verticals in a reproductive image

ANS. SMEARING

A cable that carries several video channels between facilities of a cable TV company

ANS. SUPERTRUNK

Beam alignment magnets for camera tubes are adjusted while rocking which control?

ANS. OPTICAL FOCUS

What frequency band is most suitable for LOS propagation?

ANS. VHF

It is the act of moving a camera slowly from one side of a scene toward the other

ANS. PANNING

Does not fall within the visible frequency range.

ANS. INFRARED

Intermediate power amplifier (IPA) in the transmitter is also known as ___.

ANS. DRIVER

The resistance of a photocell when light is incident on the active surface of the tube

ANS.KOCH RESISTANCE

A mirror that reflects one color but passes all other colors is called ___.

ANS. DICHROIC

Associated with certain types of microphones, the closer the sound is to the mic, the more the
bass frequencies are exaggerated.

ANS. PROXIMITY EFFECT

An abortive attempt to eliminate the CRT as the display method of large screen TV.

ANS. SCOPHONY

What is the signal rate of RS 232 normally used as interface between DTE and DCE?

ANS. 20 KBPS

What is the first radio receiver?

ANS. CRYSTAL RADIO RECEIVER

What stage in a radio transmitter isolates the oscillator from the load?

ANS. BUFFER

What is the process required in product detection?

ANS. HETERODYNING

What two basic functions are performed by the AM detector in the receiver?

ANS. RECTIFICATION AND FILTERING

In acoustics, what consists of a rapid succession of noticeable echoes?

ANS FLUTTER ECHO

In video, the frame surrounding a video picture that has different proportions from that of the TV
screen.

ANS. BEZEL

What is commonly used telephone wire?

ANS. AWG # 19

An undesirable bright or dark ring surrounding a spot of the fluorescent screen of a TV CRT.

ANS. HALO

What is the advantage of a low level modulated AM transmitter

ANS. LEAST AUDIO POWER REQUIRED

An unintelligible sound track caused by speeding up videotape playback without modifying the
audio pitch.

ANS. DONALD DUCK EFFECT

The brightness of light source is called luminous intensity, whose unit is ___.

ANS. CANDELA

Tendency to reduce excessively the tonal range of some part of the picture signal

ANS. CRUSH

EST COACHING
What component of the telephone set has the primary function of Compensating for the local
loop length?

ANS. VARISTOR

A routing scheme that delivers message to all nodes in the internet network

ANS. BROADCAST

What theorem sets a limit on the maximum capacity of a channel with a given noise level?

ANS. SHANNON-HARTLEY THEOREM

The angle between the half-power radiation points of an antenna.

ANS. BEAMWIDTH

Using a single frequency sound wave to produce a 3D image of an object. It is usually viewed on a
CRT display.

ANS. ACOUSTIC HOLOGRAPHY

Short term frequency deviation in FM broadcasting.

ANS. RESIDUAL FM

Long term frequency deviation in FM broadcasting.

ANS. DRIFT

The CATV amplifier intermediate frequency range.

ANS. 151 MHz TO 299 MHz

The high frequency range of CATV amplifier.

ANS. 300 MHz to 50,000 MHz

The worlds first commercial communications satellite

ANS. EARLY BIRD

A term usually used to describe the frequency range of any musical instrument.

ANS. AMBITUS

Noise reduction coefficient that indicates perfect reflection.

ANS. 0

How is synchronization in synchronous transmission in data communication maintained?

ANS. BY NOT ALLOWING LONG STRINGS OF 1S

What office class is local central office

Class 5

__ is 3.58 MHz subcarrier signal for color in TV

CHROMA SIGNAL

What bad electrical effect happens when the switch hook is opened?

A HIGH VOLTAGE TRANSIENT IS GENERATED

Synchronous multiplexed system have the time placement of bits ___

DEDICATED

Asynchronous multiplexed systems are used mostly for ___

DATA TRANSMISSION

The noise generated by TDM carrier system is ___ that generated by analog carrier systems

MUCH LESS THAN

Multiplexer systems used in the public network are of the ___ types

SYNCHRONOUS

An area of great brightness on a TV display or a very bright portion of a picture

HIGHLIGHT

Asynchronous data transmission requires a clock at ___

BOTH ENDS

Modem of modern design using low cost electronics to perform more advanced modulation
techniques now

TDMA

Both dot and line pattern on a TV screen are produced by ___

PULSE WAVEFORM

White-dot and cross-hatch generators are chiefly used for ___

CONVERGENCE

Which of the following is a midband cable TV channel?

A OR 14

Coaxial cable for distribution systems has an impedance of

75 OHMS

Asynchronous transmission has low-speed transmission of less than ___ kbps

2.4

The regulator in an integrated telephone circuit controls ___ and ___

CURRENT AND VOLTAGE

Ground start is ___ signaling that is Instantaneous

EITHER-WAY

The parameter that most affects transmission of high speed modem data is

PHASE DISTORTION

The voice frequency channel passband is ___ Hz

0 4000

A switch invented by Strowger, that generates much noise and cannot operate directly from DTMF
tones

STEP-BY-STEP

Time division multiplexing is ___ Transmission

DIGITAL

What is needed because of transients from lightning, induction or short circuits?

OVERLOAD PROTECTION

Line-of-transmission is a characteristic of propagation for the

VHF BAND AND UHF BAND

In TV channel 14 (470 to 476MHz), the 3.58 MHz color signal is transmitted at ___.

474.83 MHz

The MC34114 is primarily designed to work with a __ microphone.

HIGH-IMPEDANCE ELECTRET

TV receiver equipment, rabbit ears refers to ___.

RECEIVING ANTENNA

Electronic crosspoint arrays require a ___ to stay latched

MINIMUM HOLDING CURRENT

The difference between the sound carrier frequencies in two adjacent TV channel is ___

6 MHz

The difference between the sound carrier and the color subcarrier frequencies is

0.92 MHz

EST COACHING
The magnetic field is used with a ruby maser to

PROVIDE FREQUENCY ADJUSTMENTS.

the microphone pre-amplifier's balance differential input reduces the likelihood of __________ from
the receiver circuit

CROSSTALK

The most commonly used filters in SSB generation are

MECHANICAL

indicate which one of the following is not an advantage of an FM over AM.

LOWER BANDWIDTH IS REQUIRED

one of the following is an indirect way of generating FM. This is the _____.

ARMSTRONG MODULATOR

The ruby laser differs from the ruby maser in that the former

IS AN OSCILLATOR

A receiver has poor IF selectivity. It will therefore also have poor

BLOCKING

Three-point tracking is achieved with

THE PADDER CAPACITOR

The velocity factor of a transmission line

Frequencies in the UHF range normally propagate by means of

DEPENDS ON THE DIELECTRIC CONSTANT OF THE

MATERIAL USED.
SPACE WAVES.

Tropospheric scatter is used with frequencies in the following range:

UHF

In electromagnetic waves, polarization

IS DUE TO THE TRANSVERSE NATURE OF THE WAVES

As electromagnetic waves travel in free space, only one of the following can happen to them:

ATTENUATION

The absorption of radio waves by the atmosphere depends on

THEIR FREQUENCY

Electromagnetic waves are refracted when they

Diffraction of electromagnetic waves

PASS INTO A MEDIUM OF DIFFERENT DIELECTRIC

CONSTANT.
MAY OCCUR AROUND THE EDGE OF A SHARP OBSTACLE

When microwave signals follow the curvature of the earth this is known as

DUCTING

Helical antennas are often used for satellite tracking at VHF because of

THE FARADAY EFFECT

One of the following consists of non resonant antennas

RHOMBIC ANTENNA

One of the following is very useful as a multiband HF receiving antenna. This is the:

LOG PERIODIC

Which of the following antennas is best excited from a waveguide?

HORN

Which is not a reason for the use of an antenna coupler:

TO PREVENT RERADIATION OF THE LOCAL OSCILLATOR

The wavelength of a wave in a waveguide

IS GREATER THAN OF FREE SPACE

A ferrite is

A NONCONDUCTIVE WITH MAGNETIC PROPERTIES

The maximum power that may be handled by a ferrite component is limited by the

CURIE TEMPERATURE

A PIN diode is

SUITABLE FOR USE AS A MICROWAVE SWITCH

A duplexer is used
For some applications, circular waveguides may be preferred to rectangular ones because of

TO ALLOW THE ONE ANTENNA TO BE USED FOR

RECEPTION OR RETRANSMISSION WITHOUT MUTUAL
INTERFERENCE
LOWER ATTENUATION

In order to reduce cross-sectional dimensions, the waveguide to use is

RIDGED

The number of repeaters along a coaxial cable link depends on

THE BANDWIDTH OF THE SYSTEM

Armored submarine cable is used

FOR THE SHALLOW SHORE ENDS OF THE CABLE

Satellite used for intercontinental communications are known as

INTELSAT

Identical telephone numbers in different parts of a country are distinguished by their

AREA CODES

Telephone traffic is measured

IN ERLANGS

In order to separate channels in a TDM and FDM receiver, it is necessary to use

AND GATES
SUITABLE LASER DEVICES HAVE NOT YET BEEN
DEVELOPED. (Ke#20 43/57)

The 1.55 m window is not yet in use with fiber optic systems because
The modulation system inherently most noise-resistant is
The Hartley-Shannon theorem sets a limit on the

PULSE-CODE MODULATION
MAXIMUM CAPACITY OF A CHANNEL WITH A GIVEN NOISE
LEVEL

Which of the following pulse modulation systems is analog?

PWM

The number of lines per field in the United States TV system is

262

EST COACHING
The number of frames per second in the United States TV system is

30

Interlacing is used in television to

AVOID FLICKER

The signals sent by the TV transmitter to ensure correct scanning in the receiver are called

SYNC

In the United States color television system, the intercarrier frequency is

4.5 MHz

Voltage that is not found in the output of a normal monochrome receiver video detector
The carrier transmitted 1.25 MHz above the bottom frequency in the United States TV channel is
the

SWEEP

In television, 4:3 represents the

ASPECT RATIO

Equalizing pulses in TV are sent during

VERTICAL BLANKING

Another name for the horizontal retrace in a TV receiver is the

FLYBACK

Which of the following signals is not transmitted in color TV

Alignment of three electron beams in color CRT so that they land on the same triad of phosphor
dots.

A video scanning system that divides a frame into two fields, to reduce flicker

INTERLACE

If there is picture but no sound the problem is probably in the

TUNER

The TWT is sometimes preferred to the multicavity klystron amplifier, because it

HAS A GREATER BANDWIDTH

The TWT is sometimes preferred to the magnetron as a radar transmitter output tube because it is

CAPABLE OF A LONGER DUTY CYCLE

The glass tube of a TWT may be coated with aquadag to

A parametric amplifier must be

PROVIDE ATTENUATION
COOLED BECAUSE IT CANNOT OPERATE AT ROOM
TEMPERATURE

A disadvantage of microstrip compared with stripline is that microstrip

IS MORE LIKELY TO RADIATE

Surface acoustics waves propagate in

QUARTZ CRYSTAL

SAW devices may be used as

TRANSMISSION MEDIA LIKE STRIPLINE

The biggest advantage of the TRAPATT diode over the IMPATT diode is its

HIGHER EFFICIENCY

Indicate which of the following diodes does not use negative resistance in its operation

BACKWARD

One of the following is not used as a microwave mixer or detector:

PIN DIODE

One of the following microwave diodes is suitable for very low-power oscillators only:

TUNNEL

The transferred-electron bulk effect occurs in

The tunnel diode

GALLIUM ARSENIDE
USES A HIGH DOPING LEVEL TO PROVIDE A NARROW
JUNCTION

The negative resistance in a tunnel diode

IS AVAILABLE BETWEEN THE PEAK AND VALLEY POINTS

Negative resistance is obtained with a Gunn diode because of

ELECTRON TRANSFER TO A LESS MOBILE ENERGY LEVEL

The biggest disadvantage of the IMPATT diode is its

HIGH NOISE

Communications lasers are used with optical fiber, rather than in open links, to

PREVENT ATMOSPHERIC INTERFERENCE

The Shannon-Hartley law

REFERS TO NOISE

L600 mastergroup baseband has a bandwidth of __ kHz.

2728

The time when the FET is on is called

ACQUISITION

HF waves are affected by the __.

SOLAR CYCLE

In wave propagation, what layer is present only at daytime?

D LAYER

What is the major problem with VHF oscillator?

POOR FREQUENCY STABILITY

What is the aspect ratio of HDTV? (Katrina halili 69)

16:09

What is measured on a circuit where it is correctly terminated but does not have any traffic?
When a space-wave signal passes over a mountain ridge, a small part of the signal is diffracted
down the far side of the mountain. This phenomenon is called ___.
Jitter is term used to magnify phase shifts of the information transmitted. Jitter above 10 Hz is
called ___.
What figure of merit is used to measure light gathering or light collecting ability of an optical
fiber?

WHITE NOISE

What is the highest frequency that can be generated by an IMPATT microwave diode oscillator?

30 GHz

PICTURE CARRIER

CONVERGENCE

KNIFE-EDGE DIFFRACTION
WANDER
NUMERICAL APERTURE

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The number of times each second that the information displayed on a nonpermanent display is
rewritten?

REFRESH RATE

What antenna is used for radiating AM broadcast band?

In order to convert most of the earths surface, as the earth turns under the satellite path during the
24 hour period, the orbit of the GPS must maintain __ degrees ofinclination with respect to the
equator.
A set of standard for the digital transmission of information over fiber optics, based on increments
of 51 Mbps, it was developed to cost-effectively support broadband services and multi-vendor inter
networking.

/4 VERTICAL ANTENNA

In video system, what determines the maximum number of vertical picture elements?

NUMBER OF LINES ON THE SCREEN

What is the most common modulation technique used for radio telegraphy?
A scheme in the transmission of two separate information signals using two AM carriers at same
frequencies but differ in phase by 90 degrees.

FSK

What is the main disadvantage of a single tube transmitter?

FREQUENCY INSTABILITY

What fiber optic wavelength is used because of an attenuation null at the wavelength?

1.3 MICRONS

What can be used to demodulate a PAM signal?

LOW PASS FILTER (LPF)

What is the standard IF frequency for picture used in TV receivers following NTSC standard?
Loss of vertical sync causing the picture to move up or down the screen. This may result from
anti-copying devices played on commercial prerecorded videotapes.

45.75 MHz

What is the average maximum data rate for fiber optics?

50 GBPS

Number of electron beam that leaves the electron gun on a single-gun CRT.

A coaxial cable known as UHF connector.

PL-259

An undesirable bright or dark ring surrounding a spot of the fluorescent screen of a TV CRT.

HOLE

What kind of modulation in which the modulated wave is always present?

CONTINUOUS MODULATION

Shadow mask for color TV has about __ holes.

What frequency that cannot be used for reliable beyond-the-horizon terrestrial communications
without repeaters?
What figure of merit is used to express the degree of modulation scheme achieved in FSK
modulator?

300,000

What modulation system is employed by the European Cordless Telephone?

In data communications circuit, synchronous data format is used to achieve what type of
synchronization?

GFSK

What is the width of V blanking pulse?

1333 s

In FSK, rate of change of frequency at the input to the modulator is called ___.

BIT RATE

circuit that removes amplitude variations

proposed the microwave communication using satellite? (space)/ Incidentally propose the
geostationary scheme of satellite in 1940s

imager

lowest layer

D LAYER

Visual Carrier frequency of channel 7

175.25

architectural acoustics/ foundation of acoustic

W. C . Sabine

tint of color

hue

section which would be a complete antenna by itself

bay

reference of dBa

-85 dBm

video conferencing using ISDN

H.323

55?
SONET (SYNCHRONOUS OPTICAL NETWORKING)

QAM

ROLL

12 GHz
H-FACTOR

BIT

Arthur Clarke

Mogul Dillinger Effect

temperature external circuit

SID
Ambient temperature

magnetic field is introduced into a waveguide

Probe

prevents dial pulsing from ringing the bell

Anti tinkle circuit

single frequency light

The frame alignment format in the DS-1 signal contains ___ bit(s).

Monochromatic
1

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The line coding scheme used for the DS-1 signal is ___.
A circuit that transmits alternating currents whose frequencies are between given upper and lower
cut-off values, while substantially attenuating all frequencies outside this band.

bipolar

DTMF dialing takes ___

Less

BANDPASS FILTER

Trellis
Pigtail
It is the most powerful redundancy checking technique which is based on binary division.
It is a standard designed by ITU to allow telephones in the public telephone network to talk to
computers/terminals connected to the internet.

Cyclic redundancy check

Between two quantizers, the quality of one with the lower SQR will be
The most common US standard for interfacing between digital terminal equipment and modems is
____

Lower

The maximum deviation of the FM sound signal, in kilohertz, is

25

What function is not requires in an integrated telephone circuit?

Visual Display

The MC34114 is primarily designed to work with a __ microphone.

High impedance electret

If the grade of service of a telephone system indicated P of 0.05, what does it mean?

Lost call of 5%

What is the current digital video specification applying video compression?

In digital transmission using delta modulation method, what normally causes error in the
demodulated signal?

MPEG 4

Metal Film resistor has a typical flicker noise voltage range of?

0.02 to 0.20 V

What is the signal rate of RS 232 normally used as interface between DTE and DCE?
A factor expressing the ability of a electron gun to provide an electron stream under the stimulus of
a given accelerating voltage.
What occurs during CW reception if too narrow a filter bandwidth is used in the IF stage of a
receiver?
A device that prevents light from reaching the light-sensitive surface of a TV camera except during
the desired period of exposure.
When a conduit enters a box, fitting or other enclosure, ___ shall be provided to protect the wire
from abrasion.
What device can divide a data character into several channels to share its facilities usually at
slower data rates?

20kbps

What is the typical value of the velocity factor of an open wire transmission line?

0.9

What do you call a special service circuit connecting two private branch exchanges (PBX)?
A diagram used to illustrate the principle of electron bunching in velocity modulated tubes (e.g.
klystron, travelingwave tube)

TIE TRUNK

Intermittent operation in which the load condition is regularly recurrent.

Periodic duty

Occurs in the ear where a louder sound can reduce or even stop

Masking

Device incorporated in a communication receiver to reduce impulse noise

Noise blanker

Widely used balanced modulator

Lattice modulator

Commonly used filter in SSB generator

Crystal

Highest frequency to send straight upward and be returned to the earth

Critical frequency

Ship to ship communication

Frequency diversity

Highest frequency

X-ray

Ground wave communication

300Khz-3Mhz

Open ended slot antenna

Notch Antenna

Factors determine the radiation resistance of an antenna

the location of the antenna with respect to nearby

Single cell sub- divided into smaller cell

Cell splitting

Choose the Most appropriate configuration?

Network layer

Protocol used to connect other packet switching network

X.75

Used to reduced skin effect

Litz wire

H.323

EIA RS 232C

Slope overload

perveance
Filter ringing
shutter
bashing
converter

APPLEGATE DIAGRAM

EST COACHING
Popular microwave oscillator

Gunn

VSAT made available

1979

Common devise use as LNA

tunnel diode

One horizontal trace

52

3 separate signals derived from matrix

Y,I and Q

Step by step switch/ strowger switch invented in yr?

1892

ATM operates in what layer of the OSI model.

Layer 2

Basic color in TV (ZAIDO)

Red blue and green

A field consist of

262.5 scan lines

Time to scan horizontal lines

63.6s

Dielectric constants of material commonly used in transmission lines range from about

1.2 to 2.8

What is the power lost of telephone hybrid

3db

In cellular networks, standard base station antennas are replaced by

Adaptive array

What is the most desirable reflection coefficient

The ratio between the energy absorbed by a surface to the total energy received by the surface

Absorption coefficient

Determines the number of sideband components in FM

Modulation index

An interfering signal with a frequency equal to the received signal plus twice the IF is called

Image frequency

Not a baseband signal of modulation

RF carrier

Is an information signal that is sent directly without modulating any carrier

baseband

A receiver in which all RF amplifier stages require manual tuning to the desired RF is called

TRF

Which is not a part of super heterodyne receiver

Modulator

Major element will not be found in every super heterodyne receiver

The change of the modulated carrier frequency from the original RF to the IF of the super
heterodyne receiver known as

RF amplifier

Its the amplitude of the maximum negative excursion of a signal as viewed on an oscilloscope

Peak negative voltage

Diffraction of electromagnetic waves may occur_________

Around the edge of the sharp obstacle

Fluctuation in the signal strength at the receiver

Fading

____is the measurement of a unilateral antenna properties of directivity

Beam width

_____ is an antenna with a number of half-wave antenna on it

Antenna array

GSM uses what digital modulation technique

10GMSK

The vertical and horizontal pulses are separated at the

Sync separator

The sound and video signals are separated at the ________ of the TV receiver

Video detector

An ungrounded antenna near the ground

Acts as antenna array

Piston attenuator has a wavelength

Below cutoff

A _____ diode is suitable for use as a microwave switch

PIN

The cavity magnetron uses strapping to

Prevent mode jumping

A backward wave oscillator is based on the ___________

TWT

A Ruby maser amplifier must be coded because it cannot operate

Room temperature

Which voltages are not found in the output of a normal monochrome receiver video detector

Sweep voltage

What determines the rate of frequency swing for an FM broadcast transmitter

Modulation frequency

What radio system was developed to provide high-speed packet data access for GSM network

GPRS

V-32

9.6 kbps

V-34

33.6 kbps

V-90

56 kbps

Frequency translation

EST COACHING
bluetooth

720 kbps

maximum or average illumination

brightness

causes snow in the picture

weak signals

Each satellite in the IRIDIUM satellite network has how many spot beams?
Firewire, a high-speed serial bus used in computers and peripheral devices, is based on what
IEEE standard?

IEEE 1394

H or CCTV midband frequency range

162 to 168 MHz

If the 100% carrier wave of AM is suppressed, what is the power saved?

66.66%

What is the transport capacity of SONET virtual tributary (VT1.5) frame?

1.728Mbps

In synchronous network, what is the recognized international standard?

What refers to circuits that conform to the ITU-T Recommendations G.703 and G.704 for a primary
rate operating at 2.048Mbps?

Synchronous Digital Hierarchy (SDH)

Unit of luminance

Foot-lambert

Horizontal scan rate for TV in ms.

63.556 ms

Horizontal scan rate for TV in kHz.

15.734

RG-58/U characteristic impedance

Identifies calling country and public switch telephon network each subscriber has a unique code
based on what CCITT standards.

50 ohms

In a TV signal, what is the duration of the front porch prior to each horizontal sync pulse?
What is the ITU-T recommendation for error detection and correction for asynchronous
transmission of data?

1.4us

What is the standard developed by the ITU-T for use in wide area networks?

X.25

Which of the following refers to Videoconferencing standards?

ITU H.26

What is the transmission rate of a T-3 carrier circuit?

44.376 Mbps

The European digital carrier E4 has a bit rate of __ Mbps.

139.264

In order to separate the channels of TDM system, __ gates must be use?

AND

CEPT-E1

X.121

V.42