ECE Board
Exam April 2001
Which of the
following emission (AM) is used such as that when the modulation index is
doubled, the antenna current is also doubled?
J3E
ECE Board
Exam November 2000
Statements
which best describe a mixing process in radio communication.
Producing sum and difference of two
frequencies from a combination of two signals.
ECE Board
Exam April 2000
Which symbol
in radio signal emission designation is referred to type of modulation of the
main carrier?
First
ECE Board
Exam November 1999
Which of the
following in the radio emission designation refers to the first symbol?
Type of modulation of the main carrier
ECE Board
Exam April 1999
In an
emission F3E signal, what is the term for the ratio between the deviation of a
frequency modulated signal and the modulating frequency?
Modulation index
ECE Board
Exam November 1998
Which of the
following parts of the radio receiver represent the component that extracts the
desired R.F. signal from the electromagnetic wave?
Antenna
ECE Board
Exam April 1998
Refers to an
emission designation for facsimile.
A3E and F3C
ECE Board
Exam November 1997
The first
symbol in the designation of radio emission under the ITU rules refers to
type of modulation of the main carrier.
ECE Board
Exam November 1996
Which
frequency band is the standard AM radio broadcast?
MF
ECE Board
Exam April 1997
100 %
modulation in AM means a corresponding increase in total power by ___________
ECE Board
Exam March 1996
The
letter-number designation B8E is a form of modulation also known as
independent sideband emission
ECE Board
Exam April 2001
An
electromagnetic wave outside the assigned frequency of the transmitted signal
that affect a certain radio communications system.
Spurious radiation
ECE Board
Exam November 2000
What type of
emission is produced when an amplitude modulated transmitter is modulated by a
facsimile signal?
A3C
ECE Board
Exam April 2000
Determine
from the following the common use of DSB in broadcast and telecommunication,
FM/TV stereo
ECE Board
Exam November 1999
What are the
two general categories of methods for generating emission F3E?
The only way to produce an emission F3E
signal is with reactance modulator on the oscillator.
ECE Board
Exam April 1999
What is the
source of sidebands in frequency modulation?
Baseband frequency
ECE Board
Exam November 1998
Determine
the lower half-power frequency of a class-C amplifier having upper half-power
frequency of 10.025 MHz, a resonant frequency 5 MHz and a circuit Q of 10.
ECE Board
Exam April 1998
How does the
SSB transmitter output power normally expressed?
In terms of peak envelop power
ECE Board
Exam November 1997
The third
symbol in the designation of radio emission under the ITU refers to
type of information to be transmitted.
ECE Board
Exam April 1997
If the
modulation index of an AM wave is doubled, the antenna current is also doubled,
the AM system being used is
A3J.
ECE Board
Exam November 1996
Which
determines the number of sideband components in FM?
Modulation index
ECE Board
Exam March 1996
Passive
crossover components cause some frequencies to be delayed with respect to the
other frequencies at the crossoverpoint.
Phase shift
ECE Board
Exam April 2001
What
emission designation describes frequency modulated voice?
F3E
ECE Board
Exam April 2000
One of the
following is a communications filter generally used in the transceiver of a
single sideband generator.
Mechanical filter
ECE Board
Exam November 1999
Determine
the upper-half frequency of a class-C amplifier having lower half power
frequency of 10.525 MHz, a resonant frequency of 5 MHz and a circuit Q of 10.
ECE Board
Exam April 1998
Referred to
as an average power from the radio transmitter supplied to the antenna
transmission line taken during one radio frequency cycle under no modulation.
Carrier power
ECE Board
Exam April 1999
What is the
range of the lower sideband of an amplitude-modulated signal whose carrier is
1.5 MHz and the intelligence component is 50 Hz to 20 kHz?
ECE Board
Exam November 1998
This is
referred to a product of simultaneous frequency and amplitude modulation or a
carrier frequency variation which produces unwanted distortion.
Dynamic instability
ECE Board
Exam November 1997
Emission on
a frequency or frequencies immediately outside the necessary bandwidth which
result from the modulation process except spurious emission.
Out of the band
ECE Board
Exam April 1997
What is the
advantage of PTM over AM?
Much better noise immunity
ECE Board
Exam November 1996
The output
of a balance modulator is __________
LSB and USB
ECE Board
Exam March 1996
SSB
transmission requires only __________ of the bandwidth for a DSBFC
transmission.
'/2
ECE Board
Exam April 2001
A type of
modulation used in telecommunications where the modulating signal varies the
duration of the transmitter pulse.
Pulse width modulation
ECE Board
Exam April 2000
First symbol
in the designation of radio signals emission which refers to use of an
unmodulated carrier.
N
ECE Board
Exam November 1999
Let us
consider a frequency range of 405.0125 MHz to 405.0875 MHz and a 25 kHz
channeling plan, determine the center frequency of the second channel from the
lower limit.
ECE Board
Exam April 1999
What is the
first symbol of the radio signal emission having an amplitude modulated main
carrier single side band suppressed carrier?
J
ECE Board
Exam April 1998
Which of the
following refers to a double sideband full carrier?
A3E
ECE Board
Exam November 1998
Assume a
frequency range of 401.000 MHz to 401.050 MHz, if you apply 25 kHz channeling
plan, determine the center frequency of the first channel from the lower limit.
ECE Board
Exam November 1997
A single
sideband emission in which the degree of carrier suppression enables the
carrier to be reconstituted and to be used for demodulation.
Reduced carrier single sideband emission
ECE Board
Exam November 1996
What is the
type of emission used by standard AM radio broadcast?
A3
ECE Board
Exam April 1997
At 100 %
modulation, the sum of the effective voltages in both sidebands is equal to
____ % of the unmodulated carrier voltage.
ECE Board
Exam March 1996
The method
of generating FM used by broadcasting station is
Indirect
ECE Board
Exam April 2001
Measure by
which a carrier voltage is varied by the intelligence signal is referred to in
radio communications as
modulation factor
ECE Board
Exam April 2000
The process
by which the intelligence signal normally at lower frequency are emoved from
the transmission frequency after it is received in the receiver station.
Demodulation
ECE Board
Exam November 1999
What is the
process in radio communication where information or intelligence signal at
lower frequency is put unto higher radio frequency for transmission to
receiving station?
Modulation
ECE Board
Exam April 1999
If the
frequency fed to the pre-amplifier of a basic transmitter with multipliers is
composed of pair of tripplers and a doubler multipliers is 198 MHz. What
frequency should the oscillator operate?
11 MHz
ECE Board
Exam November 1998
Refers to
the first symbol in an emission designation with an amplitude modulated main
carrier represented by letter H.
Double sideband full carrier
ECE Board
Exam April 1998
With which
emission type is the capture-effect most pronounced?
FM
ECE Board
Exam April 2001
Which of the
following circuit is immediately feed into the discriminator on a frequency
modulation receiver?
Final RF amp
ECE Board
Exam April 2000
A reduction
in receiver sensitivity caused by unwanted high-level adjacent channel signals.
Desensitizing
ECE Board
Exam November 1999
A carrier
modulation where its positive peak rises to a value twice the maximum
unmodulated carrier and drops to zero at negative peak.
100% modulation
ECE Board
Exam April 1999
Best
described a frequency counter.
A frequency measuring device.
ECE Board
Exam November 1998
Assume a
frequency range of 405.0125 MHz to 405.0875 MHz and 25 kHz channeling plan,
determine the center frequency of the second channel from the lower limit.
ECE Board
Exam April 1998
What is the
mixing process?
The combination of two signals to produce
sum and difference frequencies.
ECE Board
Exam November 1997
Modulation in
which the modulated wave is always present.
Continuous modulation
ECE Board
Exam April 1997
A carrier
signal has
constant peak amplitude
ECE Board
Exam November 1996
Both
frequency and phase modulation utilize
_____ modulation
angle
ECE Board
Exam November 1999
A
communication circuit using a class-C amplifier is considered a narrow bond
amplifier if the bandwidth is less than _______ %
of its resonant frequency.
10
ECE Board
Exam March 1996
What is the
purpose of the receiver's squelch circuit?
To prevent amplified noise from reaching
the loudspeaker during the absence of an incoming signal.
ECE Board
Exam April 2001
Determine
the modulation index of a standard FM broadcast having a hypothetical maximurrr
carrier frequency deviation of ±12 kHz and a maximum modulating frequency of 4
kHz.
ECE Board
Exam April 1999
What is the
range of the upper sideband of an amplitude modulated signal whose carrier is
2.5 MHz and the intelligence component is 50 Hz to 20 kHz?
ECE Board
Exam November 1998
What is the
first symbol of a radio signal emission having an amplitude modulated main
carrier, double sideband?
A
ECE Board
Exam April 1998 .
A form of
single sideband emission where the degrees of carrier suppression enables the
carrier to be reconstituted and be used for demodulation
Reduced carrier single sideband emission
ECE Board
Exam November 1997
Average
power of a radio transmitter supplied to the antenna transmission line by a
transmitter during one radio frequency taken under the condition of no
modulation.
Carrier power
ECE Board
Exam April 2001
In an AM
wave useful power is carried by
sidebands.
ECE Board
Exam November 1999
What type of
emission is produced when an amplitude modulated transmitter is modulated by a
television signal?
A3F
ECE Board
Exam April 1999
What will
happen if the amplitude of the modulating signal of a direct FM transmitter is
increased?
Amount of frequency deviation will increase
ECE Board
Exam November, 1998
In the
regulation, the first symbol in the designation of radio emission is
type of modulation of the main carrier
ECE Board
Exam April 1997
Which
transmits only one sideband?
H3E
ECE Board
Exam November 1996
Which symbol
indicates that only one sideband is transmitted?
H3E
ECE Board
Exam March 1996
In the phase
shift method, how many circuits must be balanced?
2
ECE Board
Exam April 2001
A third
symbol emission which represent data transmission including telemetry, and
telecommand.
D
ECE Board
Exam November 1999
Which of the
following statement refers to a reason why intelligence signal cannot be
transmitted directly on their frequency?
Their frequencies are low and need very
large antennas.
ECE Board
Exam November 1998
A third
symbol emission, which represents television
F
ECE Board
Exam April 1999
How many
doubler(s) and trippler(s) must a basic transmitter have to produce a
transmitter frequency of 144 MHz from an oscillator frequency, of 8 MHz?
One doubler and two tripplers
ECE Board
Exam April 1998
What is
emission F3F?
Television
ECE Board
Exam November 1997
An AM
transmitter is rated 100 W at 100 % modulation, How much power required for the
carrier?
TO BE CONTINUE.....
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