Q.1The most common modulation system used for telegraphy is
FSK
PSK.
PCM
single tone modulation
Two tone modulation
Q.2.VSB is an abbreviation of vestigal sideband, is derived by filtering
DSB
AM
either (a) or (b)
PM
Q.3.In practical waveguide act as
low pass filter
high pass filter
band pass filter
band stop filter
Q.4.The Hartely law states that
The maximum rate of information transmission depends on the depth of modulation
The maximum rate of information depends on the channel bandwidth.
Only binary codes may be used
Redundancy is essential
Q.5.The FM signal with, a modulation index mf is passed through a
frequency tripler. The wave in the output of the tripler will have a
modulation index of
mf/9
mf/3
mf
3 mf
9mf
Q.6.Due to curvature of earth, microwave repeaters are placed at distance of about
l0 Km
50 Km
200 Km
500 Km
Q.7.In high power AM transmission, modulation is done at
Buffer stage
Oscillator stage
RF power stage
If stage
Q.8.Which of the following is not a microwave generation source?
Klystron
Magnetron
TWT
Diode
Q.9.Companding is used
In delta modulator to combat noise
To limit amplitude in PCM transmitters.
In PWM for working it with TDM
To protect small signals in PCM from quantizing distortion
In PCM to reduce the SNR
Q.10.In PCM system the SNR of the output signal increases
Inversely with bandwidth
Exponential with bandwidth
With rate of sampling
At low frequencies only
Q.11.Armstrong modulator generates
Phase modulated signal
Frequency modulated signal
Both of these
Pulse code modulated signal
AM and PCM signals
Q.12.A Klystron is a cavity acting as buncher and catcher is used as microwave tube for
Guiding waves
Velocity modulation
frequency modulation
impedance matching
All of these
Q.13.Easily adjustable tuning component in a waveguide is
plunger
plunger and stub
screw
both (a) and (c)
both (b) and (c)
Q.14.A ferrite is
A non-conductor with magnetic properties
A conductor with magnetic properties
A semiconductors
An insulator which attenuates magnetic fields
A compound with good conductivity.
Q.15.Vacuum tubes eventually fail at microwave frequencies because of their
Inter electrode capacitance
Small series inductance
Large shunt capacitance
Short transit time
Increased noise figure
Q.16.The biggest disadvantage the IMP ATT diode has is its
Low Efficiency
high noise
Low BW
inability to provide pulse operation
low power handling ability
Q.17.An attenuator is used with TWT to
prevent oscillations
increase gain
prevent saturation
help bunching
Q.18.In AM transmission the frequency, which is not transmitted is
carrier frequency
audio frequency
upper side frequency
lower side frequency
Q.19.Maximum undistorted power output of a transmitter is obtained when its modulation is:
more than 100%
100%
less than 100%
50%
Q.20.The cut off frequency of a wave guide means
lower frequencies will not be propagated
it determines the dimensions of the wave guide
frequency at which zero transmission takes place
None of above
Q.21.FM broadcast band lies in
VHF
UHF
SHF
HF
Q.22.Automatic gain control is used
to maintain the tuning correct
to reduce the voltage of loud passage of music
to maintain the same amount of output, when stations of different strength are received
to increase the amplification at high frequencies
Q.23.The modulation system inherently is most noise resistant in
SSB suppressed carrier
FM
PPM
PCM
Q.24.An FM transmitter has maximum frequency deviation of 75 KHz and
reproduces audio signal up to 15 KHz. Minimum channel width required, in
KHz is
180
120
90
60
Q.25.The antenna efficiencies achieved in practice depend upon
wave length
impedance
frequency
none of above
Q.26.The process of compressing the digital codes at the transmitter
and then expanding them back to their original form at receiver is known
as
Quantizing
companding
step sizing
modulation
Q.27.TWT is basically
an oscillator
tuned amplifier
wide band amplifier
an audio amplifier
Q.28.In PPM, message resides in
Pulses
time location of pulse edges
none of these
Q.29.Digital transmission efficiency is given by
information bits/total bits
total bits/information bits
redundant bits/information bits
none of the above
Q.30.Which of the following pulse systems requires higher bandwidth
PAM
PDM
PPM
none of these
Q.31.The speed of BRI ISDN interface is
2B + D
2D + B
30B + D
30D + B
Q.32.In case of matched load
Transmission is zero
reflection is zero
reflection is unity
transmission is equivalent to reflection
Q.33.A signal of maximum frequency of 1 KHz is sampled at Nyquist Rate.The interval between two successive samples is:
50 micro seconds
100 micro seconds
500 micro seconds
1000 micro seconds
Q.34.Man made noise id caused by:
Solar eruptions
Distant Stars
Lightning Discharges
Arc discharge in electric machines
Q.35.In order to get back the original signal, it is necessary to use:
low pass filter
high pass filter
band pass filter
band reject filter
Q.36.The function of AM detector circuit is
to rectify the input signal
to discard the carrier
to provide the audio signal
All of the above
Q.37.At microwave frequencies, the size of antenna becomes
very large
large
small
very small
Q.38.To increase the Q factor of an induction, it wound with
thicker wire
thinner wire
longer wire
wire with heavy insulation
Q.39.For handling large microwave power, the best medium is
coaxial line
rectangular waveguide
stripline
circular wave guide
Q.40.The negative resistance in Gunn diode is due to
electron transfer to a less mobile energy level
high reverse bias
electron domain formation at the junction
tunneling across the junction
Q.41.Which of the following sinusoidal oscillator is preferred for microwave frequencies?
resonant circuit oscillator
RC phase shift oscillators
negative resistance oscillators
all of the above
Q.42.When electromagnetic waves are propagated in a waveguide
they travel along the walls of the waveguide
they travel through the dielectric without touching the walls
they are reflected from the walls but do not travel along the walls
none of above
Q.43.The AGC voltage in a radio receiver is proportional to
the amount of modulation
the amplitude of audio signal
the amplitude of IF carrier
none of these
Q.44.Which of the following pulse systems is preferred for communication in presence of noise?
PAM
PDM
PPM
none of above
Q.45.Wave guides are generally made of
Cast iron or steel
White metal or gun metal
bronze or aluminium
plastic or bakelite
Q.46.With 100% modulation,ratio of side band power to total power transmitted in an amplitude modulated wave is
2/3
l/3
l/2
l/4
Q.47.In an AM wave with 100% modulation, the carrier is suppressed.The percentage of power saving will be
100%
50%
25%
66.7%
Q.48.Power factor of a purely resistive circuit is:
zero
one
0.5
infinity
Q.49.In FM, the noise can be further decreased by
decreasing deviation
increasing deviation
(c) keeping deviation constant
(d) none of these
Q.50.The audio frequency range lies between
20 to 20,000 Hz
20 to 20,000 KHz
400 to 8,000Hz
500 to 5,000 Hz
META TAGS:-TTA PREVIOUS YEAR EXAM PAPERS I DOWNLOAD TTA PREVIOUS YEAR PAPERS I TTA MODEL PAPERS I DOWNLOAD TTA PREVIOUS YEAR PAPERS I TTA SOLVED EXAM PAPERS I TTA LAST 5 YEAR PAPERS I TTA TEST EXAM PAPERS I TTA PRACTICE PAPERS I TTA LAST 10 YEARS SOLVED PAPERS I TTA ENGINEERING PAPERS I TTA SPECIALIZATION EXAM PAPERS I TTA PREVIOUS YEAR SOLVED PAPERS I TELECOM TECHNICAL ASSISTANT EXAM PAPERS I TTA GUESS PAPERS I TTA STUDY MATERIALS I TTA STUDY NOTES I DOWNLOAD TTA EXAM PAPERS I TTA MODEL PAPERS I
META TAGS:-TTA EXAM SYLLABUS I TTA HOW TO APPLY I TTA ELIGIBILITY CRITERIA I TTA AGE LIMIT I TTA AGE RELAXATION I TTA EDUCATIONAL QUALIFICATION I TTA PAPERS PATTERN I TTA STUDY MATERIALS I TTA PREPARATION TIPS I TTA PREVIOUS YEAR PAPERS I TTA EXAM RESULTS I TTA CUT-OFF MARKS I TTA SELECTION PROCESS I TTA RECUITMENT PROCESS I TTA PAY-SCALE I TTA EXAM PAPERS I TTA ELEIGIBILITY CONDITIONS I TTA MODEL PAPERS I TTA STATEWISE SYLLABUS I TTA EXAMINATION 2013 I TTA EXAM NOTIFICATION I
