BSNL TTA model paper

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BSNL stands for the Bharat Sanchar Nigam Limited. It is an Indian state-owned telecommunications company headquartered in New Delhi, India. It was founded on 15 September 2000.

BSNL conducts Telecom Technical Assistant exam. It basically consists of only written exams and along with the exam there is a medical test. This exam is held by twenty four BSNL Telecom circles.

Papers:
BSNL TTA papers
1. An open loop control system has its
(a) control action independent of the output or desired quantity
(b) controlling action, depending upon human judgment
(c) internal system changes automatically taken care of
(d) both (a) and (b)
(e) all (a),(b) and (c)
2. A servo system must have
(a) feedback system
(b) power amplifier to amplify error
(c) capacity to control position or its derivative
(d) all of these
(e) none of these
3. The major disadvantage of a feedback system may be
(a) Inaccuracy
(b) inefficiency
(c) Unreliability
(d) instability
(e) Insensitivity
4. Properties of a transfer function
(a) It is ratio of two polynomials is S and assumes zero initial conditions
(b) It depends on system elements and not input and output of the system
(c) Coefficients of the powers of S in denominator and numerator are all real constant. The order of
denominator is usually greater than or equal to the order of numerator
(d) All of these
(e) It is a function which transfer one physical system into another physical system.
5. The classical analogous of a simple lever is
(a) Capacitor bridge
(b) transformer
(c) mutual inductor
(d) either of these
6. Two blocks G1(s) and G2(s) can be cascaded to get resultant transfer function as
(a) G1(s) + G2(s)
(b) G1(s) / G2(s)
(c) G1(s) G2(s)
(d) 1+G1(s) G2(s)
(e) 1-G1(s)G2(s)
(f) two blocks cannot be cascaded
7. The principles of homogeneity and super position can be applied to
(a) linear time invariant system
(b) non-linear time invariant system
(c) digital control system
(d) both (a) and (b)
8. Pick up the nonlinear system
(a) automatic voltage regulator
(b) d.c. servomotor with high field excitation
(c) temperature control of a furnaces using thermistor
(d) speed control using SCR
(e) all of these
9. Signal flow graph (SFG) is a
(a) polar graph
(b) semi log graph
(c) log log graph
(d) a special type of graph for analyzing modem control system
(e) a topological representation of a set of differential equations
10. Disadvantages of magnetic amplifier
(a) time lag, less flexible, non-sinusoidal waveform
(b) low power consumption and isolation of the active circuit
(c) saturation of the core
(d) all of these
11. Pick up false statement regarding magnetic amplifiers
(a) The gate coil of an ideal magnetic amplifier has either zero or infinite inductance
(b) Resistance of control and gate winding is very small
(c) Magnetic amplifier gas dropping load characteristics
(d) Magnetic amplifiers are not used to control the speed of d.c. shunt motor
(e) Magnetic amplifiers can be used in automatic control of electric drivers of higher rating.
12. High power amplification is achieved by using
(a) push pull amplifier
(b) amplidyne
(c) magnetic amplifier
(d) DC amplifier
(e) D.C. generator
13. Pick up false statement regarding servomotors
(a) The d.c. servomotors are lighter than equivalent a.c. servomotors
(b) The d.c. servomotors develops higher starting and reversing torque than equivalent a.c. servomotor.
(c) A drag cup a.c. servomotor has one windings on stator and other on rotor
(d) Output power of servomotors varies from 1/20 W to 100 W
14. To reduce steady state error
(a) decrease natural frequency
(b) decrease damping
(c) increase damped frequency
(d) increase time constant
(f) increase gain constant of the system
15. A good factor for Mp should be
(a) less than 1
(b) lying between 1.1 and 1.5
(c) more than 2.2
(d) zero
(e) infinity
16. Pick up false statement. Routh-Hurwitz criterion
(a) is used for determining stability of a system
(b) is an algebraic procedure
(c) gives the exact location of roots of the characteristic equation
(d) does not indicate relative degree of stability or instability
17. Which of the following is the time domain method of determining stability of a control system
(a) Bode plot
(b) Nyquist plot
(c) Nicholos chart
(d) Routh-Hurwitz array
(e) Constant M and (fy) locus
(f) Root locus technique
18. The technique which gives transient response quickly as well as stability information is
(a) Nyquist plot
(b) Routh-Hurwitz criteria
(c) Bode plot
(d) Root locus plot
(e) Nichols plot
19. The bandwidth can be increased by use of
(a) phase lag network
(b) phase lead network
(c) both (a) and (b) in cascade
(d) both (a) and (b) in parallel
(e) none of these
20. Nyquist plot is drawn on
(a) semi log graph paper
(b) log log graph paper
(c) polar graph paper
(d) centimeter graph paper
21. If the gain margin is positive and the phase margin is negative the system is
(a) stable
(b) unstable
(c) indeterminist
22. The Bode plot is applicable to
(a) all phase network
(b) minimum phase network
(c) maximum phase network
(d) lag lead network
(e) none of these
23. The valid relation between setting time ts and rise time tr is
(a) tr>ts
(b) ts>tr
(c) ts=tr
(d) none of these
24. As a root moves further away from imaginary axis the stability
(a) increases
(b) decreases
(c) not affected
(d) none of these
25. Flat frequency response means that the magnitude ratio of output to input over the
bandwidth is
(a) variable
(b) zero
(c) constant
(d) none of above
26. How many octaves are between 200 Hz and 800 Hz
(a) Two octave
(b) One octave
(c) Four octave
(d) None of above
27. Human system can be considered as
(a) open loop system
(b) close loop system with single feedback
(c) close loop system with multivariable feedback
(d) none of these
28. In a feedback system the transient response
(a) Decays at constant rate
(b) gets magnified
(c) decays slowly
(d) decays more quickly
29. Transfer function of a system is used to calculate
(a) the steady state gain
(b) the main constant
(c) the order of system
(d) the output for any given input
(e) all of the above
30. Transfer function of a system is defined as the ratio of output to input in
(a) Laplace transform
(b) Z-transform
(c) Fourier transform
(d) Simple algebraic form
31. Introduction of feedback decreases the effect of
(a) disturbances
(b) noise signals
(c) error signals
(d) all the above
32. The system response of a system can be best tested with
(a) unit impulse input signal
(b) ramp input signal
(c) sinusoidal input signal
(d) exponentially decaying input signal
33. Which of the following is a closed loop system
(a) electric switch
(b) car starter
(c) de generator
(d) auto-pilot for an aircraft
34. Which of the following is used as an error detector
(a) potentiometer
(b) field controlled ac motor
(c) amplidyne
(d) armature controlled ac motor
35. The break away point of root loci are
(a) open loop poles
(b) closed loop poles
(c) open loop zeros
(d) closed loop zeros
36. Noise in a control system can be kept low by
(a) reducing the bandwidth
(b) attenuating such frequencies at which external signals get coupled into the system
(c) both (a) and (b)
(d) none of these
37. Main cause of absolute instability in the control system is
(a) parameters of controlling system
(b) parameters of controlled system
(c) parameters of feedback system
(d) error detector where the two signals are compared
38. Basically a controller is
(a) a amplifier
(b) a clipper
(c) a comparator
(d) a summer
39. A system with gain margin close to unity or a phase margin close to zero is
(a) highly stable
(b) highly oscillatory
(c) relatively stable
(d) none of these
40. Which of following elements is not used in an automatic control system
(a) sensor
(b) error detector
(c) oscillator
(d) final control element
41. AC systems are usually preferred to the DC systems in control applications because
(a) AC systems are cheaper
(b) AC systems are more stable
(c) AC systems have better performance characteristics and smaller in size
(d) all of these
42. A system has the transfer function (1-s)/(1+s); It is known as
(a) low pass system
(b) high pass system
(c) all pass system
(d) none of the above
43. In control systems, excessive bandwidth should be avoided because
(a) noise is proportional to bandwidth
(b) it leads to low relative stability
(c) it leads to slow speed of response
(d) none of these
44. In most systems, an increase in gain leads to
(a) larger damping ratio
(b) smaller damping ratio
(c) constant damping ratio
(d) none of these
45. A step function is applied to the input of a system and output is of the form y = t, the system is
(a) stable
(b) unstable
(c) not necessarily stable
(d) conditionally stable
46. Which of the following can be magnified by magnetic amplifier
(a) voltage
(b) current
(c) power
(d) none of above
47. The inductance is not used in lag network because of
(a) big size
(b) time delay and hysteresis losses
(c) high reactance
(d) none of these
48. Saturation in a stable control system can cause
(a) conditional stability
(b) over damping
(c) low level oscillations
(d) high level oscillations
49. Excessive noise in control systems can cause
(a) reduction in bandwidth
(b) reduction in gain
(c) saturation in amplifying stages
(d) oscillations
50. The type-0 system has
(a) net pole at the origin
(b) no pole at the origin
(c) simple at one origin
(d) two poles at the origin

(1) Instrument is a device for determining
(a) the magnitude of a quantity
(b) the physics of a variable
(c) either of the above
(d) both (a) and (b)
(2) Electronic instruments are preferred because they have
(a) no indicating part
(b) low resistance in parallel circuit
(c) very fast response
(d) high resistance in series circuit
(e) no passive elements.
(3) A DC wattmeter essentially consist of
(a) two ammeters
(b) two voltmeters
(c) a voltmeter and an ammeter
(d) a current and potential transformer
(4) Decibel is a unit of
(a) power
(b) impedance
(c) frequency
(d) power ratio
(5) A dc voltmeter may be used directly to measure
(a) frequency
(b) polarity
(c) power factor
(d)power
(6) An accurate voltmeter must have an internal impedance of
(a) very low value
(b) low value
(c) medium value
(d) very high value
(7) The insulation resistance of a transformer winding can be easily measured with
(a) Wheatstone bridge
(b) megger
(c) Kelvin bridge
(d) voltmeter
(8) A 100 V voltmeter has full-scale accuracy of 5%. At its reading of 50 V it will give an error of
(a) 10%
(b) 5%
(c) 2.5%
(d) 1.25%
(9) You are required to check the p. f. of an electric load. No p.f. meter is available. You would
use:
(a) a wattmeter
(b) a ammeter, a voltmeter and a wattmeter
(c) a voltmeter and a ammeter
(d) a kWh meter
(10) The resistance of a field coil may be correctly measured by using
(a) a voltmeter and an ammeter
(b) Schering bridge
(c) a Kelvin double bridge
(d) a Maxwell bridge
(11) An analog instrument has output
(a) Pulsating in nature
(b) Sinusoidal in nature
(c) Which is continuous function of time and bears a constant relation to its input
(d) Independent of the input quantity
(12) Basic charge measuring instrument is
(a) Duddel's oscillograph
(b) Cathode ray oscillograph
(c) Vibration Galvanometer
(d) Bailastic Galvanometer
(e) Battery Charging equipment
(13) A.C. voltage can be measured (using a d.c. instrument) as a value obtained
(a) by subtracting the d.c. reading from it's a.c. reading.
(b) Using the output function of the multimeter
(c) By using a suitable inductor in series with it
(d) By using a parallel capacitor with it
(e) None of the above
(14) A moving coil permanent magnet ammeter can be used to measure
(a) D. C. current only
(b) A. C. current only
(c) A. C. and D. C. currents
(d) voltage by incorporating a shunt resistance
(e) none of these
(15) Select the wrong statement
(a) the internal resistance of the voltmeter must be high
(b) the internal resistance of ammeter must be low
(c) the poor overload capacity is the main disadvantage of hot wires instrument
(d) the check continuity with multimeter, the highest range should be used.
(e) In moving iron voltmeter, frequency compensation is achieved by connecting a capacitor across its
fixed coil.
(16) Which of the following instrument is suitable for measuring both a.c. and d.c.
quantities.
(a) permanent magnet moving coil ammeter.
(b) Induction type ammeter.
(c) Quadrant electrometer.
(d) Moving iron repulsion type ammeter.
(e) Moving iron attraction type voltmeter.
(17) Swamping resistance is used in moving coil instruments to reduce error due to
(a) thermal EMF
(b) temperature
(c) power taken by the instrument
(d) galvanometer sensitivity.
(18) A power factor meter is based on the principle of
(a) electrostatic instrument
(b) Electrodynamometer instrument
(c) Electro thermo type instrument
(d) Rectifier type instrument.
(19) A potentiometer recorder is used for
(a) AC singles
(b) DC signals
(c) both (a) and (b)
(d) time varying signals
(e) none of these.
(20) Transformers used in conjunction with measuring instruments for measuring purposes are
called
(a) Measuring transformers
(b) transformer meters
(c) power transformers
(d) instrument transformers
(e) pulse transformers.
(21) Leakage flux in an electrical machine is measure by
(a) Ballistic galvanometer
(b) Flux meter
(c) Either (a) or (b)
(d) Vibration galvanometer
(e) CRO
(22) A C.R.O. is used to indicate
(a) supply waveform
(b) magnitude of the applied voltage
(c) B.H. loop
(d) all of these
(e) Magnitude of the current flowing in it.
(23) An oscillator is a
(a) an amplifier having feedback network
(b) a high gain amplifier
(c) a wide band amplifier
(d) a untuned amplifier
(e) None of these
(24) Distortion can be measured by
(a) Wave meter
(b) Digital filters
(c) Wein bridge circuit
(d) Bridge T filter circuit
(25) Series connected Q- meter is preferable for measurement of components having
(a) high impedance
(b) low impedance
(c) both (a) and (b)
(d) high frequency
(e) low capacitance
(26) A potentiometer is
(a) an active transducer
(b) a passive transducer
(c) a secondary transducer
(d) a digital transducer
(e) a current sensing transducer
(27) The basic components of a digital voltmeter are:
(a) A/D converter and a counter
(b) A/D converted and a rectifier
(c) D/A converter and a counter
(d) Ramp generator and counter
(e) Comparator
(28) Which of the following electrical equipment cannot convert ac into dc
(a) diode
(b) converter
(c) transformer
(d) mercury arc rectifier
(29) Voltage measurement are often taken by using either a voltmeter or
(a) an ammeter
(b) an ohmmeter
(c) an oscillator
(d) a watt-meter
(30)The electric device which blocks DC but allows AC is called:
(a) capacitance
(b) inductor
(c) an oscilloscope
(d) a watt-meter
(31 ) The range of an ammeter can be extended by using a
(a) shunt in series
(b) shunt in parallel
(c) multiplier in series
(d) multiplier in parallel
(32)A device that changes one form of energy to another is called
(a) rheostat
(b) oscillator
(c) transducer
(d) varicap
(33) Aquadag is used in CRO to collect
(a) primary electron
(b) secondary electron
(c) both primary and secondary
(d) none of above
(34) A vertical amplifier for CRO can be designed for
(a) only a high gain
(b) only a broad bandwidth
(c) a constant gain time bandwidth product
(d)all of the above
(35) One of the following is active transducer
(a) Strain gauge
(b) Selsyn
(c) Photovoltic cell
(d) Photo emissive cell
(36) The dynamic characteristics of capacitive transducer are similar to those of
(a) low pass filter
(b) high pass filter
(c) band pass filter
(d) band stop filter
(37) Thermocouples are
(a) passive transducers
(b) active transducers
(c) both active and passive transducers
(d) output transducers
(38) The size of air cored transducers as compare to iron core counter part are
(a) bigger
(b) smaller
(c) same
(39) From the point of view of safety, the resistance of earthing electrode should be:
(a) low
(b) high
(c) medium
(d) the value of resistance of electrode does not effect the safety
(40) In CRT the focusing anode is located
(a) between pre accelerating and accelerating anodes
(b) after accelerating anodes
(c) before pre accelerating anodes
(d) none of above
(41) Which transducer converts heat energy into electrical energy
(a) I. V. D. T.
(b) thermocouple
(c) photoconductor
(d) none of the above
(42) Which of photoelectric transducer is used for production of electric energy by converting
solar energy
(a) photo emission cell
(b) photo diode
(c) photo transistor
(d) both (b) and (c)
(43) Which of the following instruments consumes maximum power during measurement?
(a) induction instruments
(b) hot wire instruments
(c) thermocouple instruments
(d) electrodynamometer instruments
(44) Which of the following meters has the best accurancy
(a) moving iron meter
(b) moving coil meter
(c) rectifier type meter
(d) thermocouple meter
(45) The function of the safety resistor in ohm meter is to
(a) limit the current in the coil
(b) increase the voltage drop across the coil
(c) increase the current in the coil
(d) protect the battery
(46) Which of the following instruments is free from hysteresis and eddy current losses?
(a) M.l. instrument
(b) electrostatic instrument
(c) electrodynamometer type instrument
(d)all of these
(47) The dielectric loss of a capacitance can be measured by
(a) Wien bridge
(b) Owen bridge
(c) Schering bridge
(d) Maxwell bridge
(48) Reed frequency meter is essentially a
(a) recording system
(b) deflection measuring system
(c) vibration measuring system
(d) oscillatory measuring system
(49) In measurements made using a Q meter, high impedance elements should preferably be
connected in
(a) star
(b) delta
(c) series
(d) parallel
(50) A digital voltmeter measures
(a) peak value
(b) peak-to-peak value
(c) rms value
(d) average value

1. Pick up wrong statement
(a) A group of interconnected individual components known as circuit elements is called a network.
(b) A humped network is an arrangement of physically separate resistors, inductors and capacitors.
(c) Distributed network is one, which the resistive, inductive and capacitive effects are inseparable for
network analyses.
(d) A branch is a network having four elements.
2. Kirchoff's laws for networks are:
(a) The algebraic sum of branch currents meeting at any node is zero.
(b) The algebric sum of voltage drops in any set of branches forming a closed circuit or loop must be
equal to zero.
(c) Both (a) and (b)
(d) Neither (a) and (b)
3. Mutually coupled circuit is a circuit which is:
(a) Bilateral
(b) Unilateral
(c) None of these
(d) Either (a) or (b)
4. Duality is a
(a) Transformation in which current and voltages are interchanged
(b) Active sources become passive sources
(c) Passive sources become active sources
(d) Both (b) and (c)
5. Combined inductance of two inductors L1 and L2 connected and voltages are interchanged
(a) L1 + L2
(b) (L1 + L2)/ L1
(c) (L1 + L2) / (L1 X L2)
(d) (L1 X L2) / (L1 + L2)
6. Normal analysis techniques are based on
(a) Thevenin's theorem
(b) Tellegan's theorem
(c) Superposition theorem
(d) Kirchoff's Law
7. Two voltage sources can be connected in parallel when they are equal in
(a) Magnitude
(b) Frequency
(c) Phase
(d) All the above
8. The kirchoff's law fail in
(a) Linear circuits
(b) Non-linear circuits
(c) Lumped parameter circuits
(d) Distributed parameter circuits
9. Which of the following is a nonreciprocal network ?
(a) A network consisting of all resistances
(b) A network consisting of all capacitances
(c) A network consisting of all inductances
(d) A transistor model
10. When two systems obey equations of the same form the systems are said to be
(a) Similar system
(b) Identical system
(c) Analogous system
(d) Digital system
11. For a highly selective circuit
(a) It must have large value of Q
(b) It must have high value of capacitance to produce resonance at fixed frequency
(c) Either (a) or (b)
(d) Neither (a) nor (b)
12. A network consisting of four terminals is called a
(a) One port network
(b) Two port network
(c) Four port network
(d) None of the above
13. Driving point of a network is
(a) A port where voltage or current source is connected
(b) A terminal where load is connected
(c) A port where load is connected
(d) None of the above
14. Ceramic filters are similar in construction to
(a) Crystal filters
(b) Crystal ladder filters
(c) Crystal lattice
(d) Mechanical filters
15. When two port networks are connected in parallel the resultant
(a) Z parameters are the some of individual parameters
(b) Y- parameters are the some of individual parameters
(c) Both (a) and (b)
(d) Neither (a) nor (b)
16. Electric wave filters
(a) Allow electric signals with specified frequency range
(b) Suppress signals outside a specified range
(c) Both (a) and (b) occurs simultaneously
(d) Either (a) or (b) occur at a time
17. A cascade connection of low pass filter and high pass filter is called
(a) Band pass filter
(b) Band elimination filter
(c) Neither (a) nor (b)
(d) Both (a) and (b)
18. The response of a network is decided by the location of
(a) Its poles
(b) Its zeros
(c) Either (a) nor (b)
(d) Both (a) and (b)
19. Example of two port network is
(a) Transformer
(b) Transmission line
(c) Bridge circuit and transistor circuit
(d) All of the above
20. The circuit whose properties are same in either direction is called
(a) Universal circuit
(b) Reversible circuit
(c) Unilateral circuit
(d) Bilateral circuit
21. Distortion in transmission line is due to
(a) Delay distortion
(b) Phase distortion
(c) Frequency distortion
(d) All the above
22. The general parameters distributed along a transmission line are
(a) R&L only
(b) L&C only
(c) C&G only
(d) R, L, C&G
23. Phase distortion is prominently caused by
(a) circuit transients
(b) non linear characteristics
(c) linearity
(d) none
24. The voltage or current from the receiving end towards the sending end, decreasing in
amplitude with increasing distance from the load is called
(a) incident wave
(b) medium wave
(c) reflected wave
(d) none of above
25. E.M. Waves of UHF is propagated efficiently via
(a) parallel wire transmission lines
(b) open wire transmission lines
(c) wave guides
(d) coaxial cables
26. Norton theorem is valid for network containing only
(a) linear elements
(b) no linear elements
(c) resistance
(d) reactance
27. The maximum power is absorbed by one network from other, joined to it at two terminals
when the impedance of one is
(a) complex conjugate of other
(b) square root of other
(c) same as other
(d) none of above
28. The decrease in effective conductor cross section at high frequencies
(a) decrease the conductor resistance
(b) increase the conductor resistance
(c) no change in conductor resistance
(d) none of above
29. Voltage standing wave ratio lies in the range
(a) 0 to 1
(b) 1 to infinity
(c) 0 to infinity
(d) -1 to +1
30. Attenuators have applications
(a) in AC circuits only
(b) in DC circuits only
(c) in AC as well DC circuits
(d) in low frequency circuits only
31. In an network
(a) the number of tree branches is equal to the number of links
(b) the number of tree branches cannot be equal to the number of links
(c) the number of tree branches has no relation with the number of links branches
(d) none of these
32. In open line transmission systems, attenuation is more at
(a) lower frequencies
(b) medium frequencies
(c) higher frequencies
(d) remains constant
33. a power ratio 100 is equivalent to
(a) 10 dB
(b) 20 dB
(c) 50 dB
(d) 100 dB
34. The velocity factor for small widely spaced conductors such as open wire line in air is very
nearly
(a) 0.66
(b) 0.98
(c) 0.82
(d) 0.76
35. Transmission of power to a load over a transmission line achieves optimum value when
standing wave ratio (SWR) becomes
(a) 2 : 1
(b) 1 : 2
(c) 1 : 1
(d) 1 : 10
36. The VSWR in a short circuited loss less transmission line equals
(a) infinity
(b) unity
(c) zero
(d) none of above
37. The velocity factor of a transmission line
(a) is always greater than unity
(b) depend upon the permittivity of the surrounding medium
(c) is lease for air medium
(d) is governed by skin effect
38. Which of the following is not correct
(a) voltage source is an active element
(b) current source is a passive element
(c) resistance is a passive element
(d) conductance is a passive element
39. A network is said to be nonlinear if it does not satisfy
(a) superposition condition
(b) homogeneity condition
(c) both superposition and homogeneity conditions
(d) associative condition
40. An capacitor with zero initial condition at t = 0+ act as a
(a) short circuit
(b) open circuit
(c) current source
(d) voltage source
41. An inductor stores energy in
(a) electrostatic field
(b) electromagnetic field
(c) magnetic field
(d) core
42. In series LCR circuits, at resonance,
(a) current is maximum, power factor is zero
(b) current is maximum, power factor is unity
(c) current is minimum, power factor is unity
(d) none of above
43. In an RCL series circuit, during resonance, the impedance will be
(a) zero
(b) minimum
(c) maximum
(d) none of above
44. When a source is delivering maximum power to load, the efficiency of the circuit is always
(a) 50%
(b) 75%
(c) 100%
(d) None of above
45. In a linear network, when the ac input is doubled, the ac output becomes
(a) two times
(b) four times
(c) half
(d) one forth
46. A passive network has
(a) current sources but no voltage sources
(b) voltage sources but no current sources
(c) both current and voltage sources
(d) no voltage or current sources
47. Two resistances are connected in parallel and each dissipates 50 waits. The total power
supplied by the source is
(a) 25 watts
(b) 50 watts
(c) 100 watts
(d) 200 watts
48. Three bulbs of 60 watts each are connected is parallel across 220v, 50 Hz supply. If one bulb
burns out
(a) only remaining two will operate
(b) remaining two will not operate
(c) all of three will operate
(d) there will be heavy current from the supply
49. The amplitude of an audio signal is 10 and that of carrier wave is 50. Percentage modulation
is:
(a) 0.2
(b) 20
(c) 5
(d) 60
50. The main advantage of PCM system is:
(a) lower bandwidth
(b) lower power
(c) lower noise

Address:
Bharat Sanchar Nigam Limited
Janpath, HC Mathur Lane, New Delhi, DL ‎
011 2373 4010 ‎

Map:
[MAP]https://maps.google.co.in/maps?q=Bharat+Sanchar+Nigam+Limited&hl=en&ll=28.63 8773,77.367783&spn=0.356763,0.653687&sll=28.475934 ,77.516441&sspn=0.178658,0.326843&hq=Bharat+Sancha r+Nigam+Limited&t=m&z=11&iwloc=A[/MAP]
Here I am atteching a two pdf file which contains the previous year’s question papers of the BSNL TTA exam. Click to download:..........

[Quick Sam]

1. What is the name of the software that allows us to browse through web pages?
(a) Browser
(b) Mail Client
(c) FTP Client
(d) Messenger
2. What is the address given to a network called?
(a) System Address
(b) SYSID
(c) Process ID
(d) IP Address
3. Which one of the following is a valid DOS command?
(a) LIST *.*
(b) LIST???.
(c) RECOVER A:
(d) RENAME A:SAMPLE.TXT C:TEST.DOC
4. All system settings in WINDOWS are stored in:
(a) CONTROL.INI
(b) MAIN.INI
(c) SYSTEM.INI
(d) SETTING.INI
5. Which number system is usually followed in a typical 32-bit computer?
(a) 2
(b) 10
(c) 16
(d) 32
6. Which of the following is not an output device:
(a) Printer
(b) Scanner
(c) Flat Screen
(d) Touch Screen
7. A microprocessor is a processor with reduced
(a) instruction set
(b) power requirement
(c) MIPS performance
(d) none of the above
8. Which of the following is not an output of an assembler?
(a) executable program
(b) source listing with line numbers and errors
(c) a symbol table
(d) object program
9. Which layer of OSI model is responsible for routing and flow control:
(a) Presentation
(b) Transport
(c) Network
(d) Data Link
10. Arrays are passed as arguments to a function by
(a) value
(b) reference
(c) both a and b
(d) none of the above
11. Array is:
(a) linear data structure
(b) non-linear structure
(c) none of the above
12. A data structure in which elements are added and removed from only one end, is known as:
(a) Array
(b) Stack
(c) Queue
(d) None of the above
13. A diamond-shaped box in an Entity-Relationship diagram refers to:
(a) Entity
(b) Relationship
(c) Attribute
14. The principle means of identifying entities within an entity set is:
(a) Primary Key
(b) Record
(c) Attribute
(d) Tuple
15. Modem refers to:
(a) Modulator
(b) Modulation
(c) Demodulator
(d) Modulator and Demodulator
16. C language is available for which of the following Operating Systems?
(a) DOS
(b) Windows
(c) Unix
(d) All of the above
17. Which of the following have the fastest access time?
(a) Magnetic Tapes
(b) Magnetic Disks
(c) Semiconductor Memories
(d) Compact Disks
18. DMA stands for:
(a) Direct Memory Allocation
(b) Distinct Memory Allocation
(c) Direct Memory Access
(d) Distinct Memory Access
19. Array subscripts in C always start at:
(a):1
(b) 0
(c) 1
(d) Value provided by user
20. Which type of commands in DOS needs additional files for their execution?
(a) Batch Commands
(b) Internal Commands
(c) External Commands
21. Which of the following statements in regard to Directories is false?
(a) Directories can exist inside directories
(b) The root directory is always at the highest level
(c) Directories with files can be deleted
(d) Directories cannot be renamed
22. It is better to buffer a table when
(a) When a table is read infrequently
(b) When a table is linked to check tables
(c) When a table is read frequently and the data seldom changes
(d) When a single record is to be picked up
23. The Operating System is responsible for:
(a) Controlling peripheral devices such as monitor, printers, disk drives
(b) Provide an interface that allows users to choose programs to run and to manipulate files
(c) Manage users’ files on disk
(d) All of the above
24. A company whishes to connect two sites in different parts of the country together. It is decided to
use the telephone system. What device should be connected to the fileservers on each site?
(a) Router
(b) Modem
(c) Switch
(d) Hub
25. What is a file server?
(a) A computer that performs a service for other computers
(b) A computer that controls the printers on the network
(c) A computer that stores files that are created by network users
26. What is the Protocol used for the Internet?
(a) IPX/SPX
(b) NetBIOS/NetBEUI
(c) CDMA/CA
(d) TCP/IP
27. Which one of the following is not a Normal Forms (Normalization) rule with regards to the Relational
Model?
(a) All fields within a table must relate to or directly describe the Primary Key.
(b) Repeating Groups must be eliminated from tables.
(c) Fields that can contain non-numeric data are to be removed and placed within their own tables with
an associated Primary Key.
(d) Redundant data is to be eliminated by placing the offending fields in another table.
28. Choose the answer which best describes the term Primary Key:
(a) The Primary Key is a field that contains data that can be duplicated.
(b) The Primary Key is a field that contains data that is unique.
(c) The Primary Key is a field that is never associated with any field in other tables.
(d) The Primary Key field is a concept used only in Microsoft Access.
29. Which technique is used to reduce the size of a file:
(a) Compression
(b) Decompression
(c) Encryption
(d) Decryption
30. BIOS stands for
(a) Binary Input Output Set
(b) Binary Input Output System
(c) Basic Input Output Set
(d) Basic Input Output System
31. A floppy disk is consisting of 40 tracks, each track contains 100 sectors, and the capacity of a sector
is 512 bytes, what is the approx. size of that disk?
(a) 1 MB
(b) 2 MB
(c) 4 MB
(d) 8 MB
32. What is the binary equivalent of a decimal number 68:
(a) 1000100
(b) 1100100
(c) 1000010
(d) 1000001
33. Assembly language to machine language translation is:
(a) One-to-One
(b) One-to-Many
(c) Many-to-One
(d) Many-to-Many
34. Maximum size of IP address is:
(a) 12 bits
(b) 24 bits
(c) 32 bits
(d) 48 bits
35. RAM stands for
(a) Read Access Memory
(b) Read After Memory
(c) Random Access Memory
(d) Random After Memory
36. What is the final value of sum?
main ()
{
int sum=1;
for(;sum<=9
printf(%d\n, ++sum);
}
(a) 9
(b) 10
(c) 11
(d) none of the above
37. If c is a variable initialized to 1, how many times the following loop be executed:
while(c>0 && c<60)
{
c++;
}
(a) 59
(b) 60
(c) 61
(d) none of the above
38. The declaration void fun(int) indicates the fun is a function which:
(a) has no arguments
(b) returns nothing
(c) both a and b
(d) none of the above
39. Out of the following which is not valid network topology:
(a) Bus
(b) Star
(c) Circle
(d) Tree
40. The overall logical structure of a database can be expressed graphically by:
(a) Data Flow Diagram
(b) Flow Chart
(c) Directed Graph
(d) Entity-Relationship Diagram
41. CARRY, in a half-adder, can be obtained using:
(a) OR gate
(b) AND gate
(c) EX-OR gate
(d) EX-AND gate
42. The memory that requires refreshing of data is:
(a) SROM
(b) DROM
(c) SRAM
(d) DRAM
43. The minimum number of bits required to represent numbers in the range:28 to +31 is-
(a) 5
(b) 6
(c) 7
(d) 8
44. Which bus carries information between processors and peripherals?
(a) Data bus
(b) Control bus
(c) Address bus
(d) Information bus
45. Which part of the computer perform arithmetic calculations?
(a) Control unit
(b) Registers
(c) ALU
(d) CPU
46. A gigabyte represents:
(a) 1 billion bytes
(b) 1000 kilobytes
(c) 230 bytes
(d) 10 megabytes
47. The minimum number of bits required to store the hexadecimal number FF is:
(a) 2
(b) 4
(c) 8
(d) 16
48. Cache memory enhances:
(a) memory capacity
(b) memory access time
(c) secondary storage capacity
(d) secondary storage access time
49. A UPS:
(a) increases the storage capacity of a computer system
(b) increases the processor speed
(c) provides backup power in the event of a power cut\
(d) none of the above
50. An RDBMS is a:
(a) Remote DBMS
(b) Relative DBMS
(c) Reliable DBMS
(d) Relational DBMS

I am looking for Model Question Papers of BSNL (Bharat Sanchar Nigam Limited) TTA Exam so please provide me the same?

[Arun Vats]

Here I am providing you Model Question Papers of BSNL (Bharat Sanchar Nigam Limited) TTA (Telecom Technical Assistant) Exam.

Model Question Papers of BSNL TTA Exam:

1. The probability of hitting a target from one gun 9/10, from another gun is 7/10. If both gun are fired at the same time, the probability of hitting the target is
(A) 2/20
(B) 63/100
(C) 16/20
(D) 63/20

2. If the three vectors a, b and c are coplanar , then the missed product a x b. c is
(A) Zero
(B) Non-Zero
(C) Unity
(D) Non of these

3. Limit sin x/x is x?0
(A) not defined
(B) 1
(C) zero
(D) -1

4. When a body hits an obstacle, the force with which it hits the obstacle depends upon its
(A) average velocity
(B) velocity at the instant of collision
(C) initial velocity
(D) all of these

5. The wavelength of visible light is of the order of
(A) 1µm
(B) 100 µm
(C) 1mm
(D) 1 Å

6. Whenever a source of sound moves towards an observer
(A) the frequency heard by the observer is less than that of the source
(B) the frequency heard by the observer is greater than that of the source
(C) the frequency heard by the observer is unchanged
(D) the wavelength of sound heard is greater than that of the sound emitted

7. Moving electric charges will interact with
(A) electric field only
(B) magnetic field only
(C) both of these
(D) none of these

8. Gamma radiation is most similar to
(A) sound waves
(B) X-ray
(C) Alpha particles
(D) neutrons

9. The fundamental particle responsible for keeping the nucleus together is
(A) meson
(B) anti proton
(C) positron
(D) muon

10. Air contains 21% oxygen by volume and the rest nitrogen. If the barometer pressure is 740 mm of Hg the partial pressure of oxygen is close to
(A) 155 mm of Hg
(B) 310 mm of Hg
(C) 465 mm of Hg
(D) 162 mm of Hg

11. In the electrolytic cell
(A) electrical energy is converted into chemical energy
(B) chemical energy is converted into electrical energy
(C) mechanical energy is converted into potential energy
(D) potential energy is converted into kinetic energy

12. The force required to maintain a body at constant speed in free space is equal to
(A) the mass of the body
(B) zero
(C) the weight of the body
(D) the force required to stop it

13. If the length of a spring is halved, the spring constant becomes
(A) half
(B) 1/4th
(C) double
(D) four times

14. The coefficient of static friction depends on
(A) the material of the bodies in contact
(B) the quality of surface finish of the bodies
(C) the presence of foreign matter between the surface
(D) all of these

15. The units of angular impulse in SI system are
(A) Nms
(B) Ns
(C) Nm/s
(D) Ns/m

16. Stainless steel contains iron and
(A) Chromium and nickel
(B) Chromium and carbon
(C) Nickel and carbon
(D) Chromium and manganese

17. The property of material by which it offers resistance to scratching or indentation is called
(A) Brittleness
(B) Hardness
(C) Toughness
(D) Resilience

18. The failure of a material due to repeated stressing is known as
(A) Creep
(B) Fracture
(C) Fatigue
(D) Brittle Fracture

19. The electric device which blocks DC but allows AC is called
(A) Capacitor
(B) Inductor
(C) Amplifier
(D) Transducer

20. When a charge is moved from one point to another in an electric field, the work done is
(A) independent of the path
(B) zero along the direction of the field
(C) measured in Joules per metre
(D) measure in Volt per metre

21. A capacitor with lowest leakage is
(A) Paper
(B) Ceramic
(C) Polyester
(D) Mica

22. A zener diode operates
(A) In an extremely high forward bias
(B) In an extremely low reverse bias
(C) In an extremely low forward bias
(D) In a reverse bias higher than laid down voltage

23. The specific gravity of a lead acid cell is often used as a measure of its
(A) Rate of discharge
(B) Operating temperature
(C) State of charge
(D) Life expectancy

24. An uniformly distributed load is one which
(A) Acts at a point on a beam
(B) Spreads uniformly over the whole length of a beam
(C) Varies uniformly over the whole length of a beam
(D) loads the beam from one end only

25. A steam engine device which keeps the speed of the engine, all loads, constant is known as
(A) Flywheel
(B) Eccentric
(C) Connecting rod
(D) Governor

26. The refrigerant hiving the lowest freezing point is
(A) Ammonia
(B) Carbon dioxide
(C) Freon – 11
(D) Freon – 22

27. Heat and work are
(A) Path functions
(B) Properties of a substance
(C) Point functions
(D) Absolute units


1. One of the following statement which is true for relative dielectric constant is -

a) It is dimensionless

b) It is not equal to unity for vacuum

c)) It?s value for all substances is less than one

d)) None

2. Pure metals generally have-

a) high conductivity and low temperature coefficient

b) high conductivity and large temperature coefficient

c) low conductivity and zero temperature coefficient

d) low conductivity and high temperature coefficient

3. For small size, high frequency coils, the most common core material is

a) Air

b) Ferrite

c) Powdered ion

d) Steel

4. For an abrupt junction Varactor diode, the dependence of device capacitance (C) on applied reverse bias (V) is given by-

a) C a V1/3

b) C a V-1/3

c) C a V1/2

d) C a V-1/2

5. A superconductor is a-

a) A material showing perfect conductivity and Meissner effect below a critical temperature

b) A conductor having zero resistance

c) A perfect conductor with highest dimagnetic susceptibility

d) A perfect conductor which becomes resistive when the current density through it exceeds a critical value

6. When a semiconductor based temperature transducer has a temperature coefficient of ?2500 mV/0C then this transducer is indeed a-

a) Thermistor

b) Forward biased pn junction diode

c) Reverse biased pn junction diode

d) FET

7. The location of lightning arrestor is -

a) Near the transformer

b) Near the circuit breaker

c) Away from the transformer

d) None

8. Time constant of an RC circuit increases if the value of the resistance is -

a) Increased

b) Decreased

c) Neither a nor b

d) Both a and b
9. Intrinsic semiconductors are those which -

a) Are available locally

b) Are made of the semiconductor material in its purest from

c) Have more electrons than holes

d) Have zero energy gaps

10. The primary control on drain current in a JFET is exerted by -

a) Channel resistance

b) Size of depletion regions

c) Voltage drop across channel

d) Gate reverse bias
11. The electrical conductivity of metals which is expressed in ohm-1 m-1 is of the order of -

a) 1010

b) 105

c) 10-4

d) 10-6

12. When biased correctly, a zener diode ?

a) acts as a fixed resistance

b) has a constant voltage across it

c) has a constant current passing through it

d) never overheats
13. The current amplification factor adc is given by ?

a) IC/IE

b) IC/IB

c) IB/IC

d) IB/IC

14. Compared to bipolars, FETs have-

a) high input impedance

b) low input impedance

c) same input impedance

d) none

15. The source-drain channel of JFET is -

a) ohmic

b) bilateral

c) unilateral

d) both a and b

16. diac is equivalent to a -

a) Pair of SCRs

b) Pair of four layer SCRs

c) Diode and two resistors

d) Triac width
17. When a sample of N type semiconductor has electron density of 6.25 ? 1011 /cm3 at 300K and if the intrinsic concentration of carriers in this sample is 2.5 ? 1013/cm3 then the hole density will be ?

a) 106/cm3

b) 103/ cm3

c) 1010/ cm3

d) 1012/ cm3

18. The statement ‘In any network of linear impedances, the current flowing at any point is equal to the algebraic sum of the currents caused to flow at that point by each of the sources of emf taken separately with all other emf’s reduced to zero? represents -

a) Kirchhoff’s law

b) Norton’s theorem

c) Thevenin’s theorem

d) Superposition theorem

19. One of the following modes which has the characteristics of attenuation becoming less as the frequency is increased and is attractive at icrowave frequencies of circular cylindrical wave guides is ?

a) TE1 mode

b) TM01 mode

c) TE01 mode

d) Higher order mode
20. A two-port network is symmetrical if ?

a) z11z22 ? z12z21 = 1

b) h11h22 ? h12h21 = 1

c) AD ? BC = 1

d) y11y22 ? y12y21 = 1

21. For transmission line load matching over a range of frequencies, it is best to use a-

a) balun

b) broad band directional coupler

c) double stub

d) single stub of adjustable position

22. The poles and zeros of a driving point function of a network are simple and interlace on the negative real axis with a pole closest to the origin. It can be realised -

a) by an LC network

b) as an RC driving point impedance

c) as an RC driving point admittance

d) only by an RLC network

23. Poles and zeros of a driving point function of a network are simple and interlace on the jw axis. The network consists of elements ?

a) R and C

b) L and C

c) R and L

d) R, L and C

24. For a two port reciprocal network, the output open circuit voltage divided by the input current is equal to ?

a) B

b) Z12

d) h12

25. In a short electric doublet the radiation properties are so that-

a) The induction field diminishes as the square root of the distance and is only appreciable in the vicinity of the conductor.

b) In the radiation, magnetic field is minimum when the current is maximum.

c) The radiation resistance of a short doublet antenna is extremely high.

d) Mean rate of power through a unit area of spherical sphere surrounding this doublet is proportional to the square of the elemental length, other factors remaining constant.

26. The frequency modulated (FM) radio frequency range is nearly -

a) 250 ?300 MHz

b) 150 ? 200 MHz

c) 90 ? 105 MHz

d) 30-70 MHz

27. In an underground cable the distortion in the transmission of carrier frequency can be eliminated by using -

a) Inductive loading

b) Resistive loading

c) Capacitive loading

d) Shielding

28. The charachteristic impendance of a transmission line with inductance 0.294 mH /m and capacitance 60 pF/m is -

a) 49 W

b) 60 W

c) 70 W

d) 140 W

30. For a quarter wavelength ideal transmission line of characteristic impedance 50 ohms and load impedance 100 ohms, the input impedance will be ?

a) 25W

b) 50W

c) 100W

d) 150W

31. The depth of penetration or skin depth for an electromagnetic field of frequency ?f? in a conductor of resistivity r and permeability m is-

a) inversely proportional to r and f and directly proportional to m

b) directly proportional to r and inversely proportional to f and m

c) directly proportional to f and inversely proportional to r and m

d) inversely proportional to r and m and directly proportional to f
32. When an antenna has a gain of 44dB then assuming that the main beam of the antenna is circular in cross-section the beam width will be -

a) 0.4456 0

b) 1.44560

c) 2.44560

d) 3.44560

33. Lens antennas used for microwaves are usually made of -

a) Polystyrene

b) Glass of low refractive index

c) Paraboloid surfaces

d) Dielectric media having large refractive index

34. One of the following types of instrument which is an electrometer is -

a) Electrodynamometer

b) PMMC

c) Electrostatic

d) Moving iron

35. When an ac current of 5A and dc current of 5A flow simultaneously through a circuit then which of the following statement is true ?

a) An ac ammeter will read less than 10A but more than 5A

b) An ac ammeter will read only 5A

c) A dc ammeter will read 10A

d) A dc ammeter will read zero
36. When Q factor of a circuit is high, then -

a) power factor of the circuit is high

b) impedance of the circuit is high

c) bandwidth is large

d) none of these

37. The resolution of a logic analyser is -

a) the maximum number of input channels

b) the minimum duration of the glitch it can capture

c) it’s internal clock period

d) the minimum amplitude of input signal it can display
38. A memoryless system is ?

a) causal

b) not causal

c) nothing can be said

d) none

39. An air capacitor is a ?

a) time variant

b) active device

c) time invariant

d) time invariant and passive device

40. Thermistors are made of -

a) pure metals

b) pure insulators

c) sintered mixtures of metallic oxides

d) pure semiconductor

41. Pirani gauge is used to measure ?

a) very low pressures

b) high pressures

c) pressures in the region of 1 atm

d) fluid flow

42. These circuits converts input power at one frequency to output power at a different frequency through one stage conversion ?

a) AC voltage controllers

b) Cyclo converters

c) Phase controlled rectifiers

d) Inverters

43. In a forward voltage Triggering thyristor changes from ?

a) off state to on state

b) on state to off state

c) on state to on state

d) off state to off state
44. A thyristor, when triggered, will change from forward blocking state to conduction state if its anode to cathode voltage is equal to -

a) peak repetitive off state forward voltage

b) peak working off state forward voltage

c) peak working off state reverse voltage

d) peak non-repetitive off state forward voltage

45. Gate characteristic of a thyristor-

a) is a straight line passing through origin

b) is of the type Vg = a + bIg

c) is a curve between Vg and Ig

d) has a spread between two curves of Vg ? Ig

46. A four quadrant operation requires-

a) two full converters in series

b) two full converters connected back to back

c) two full converters connected in parallel

d) two semi converters connected back to back
47. If for a single phase half bridge inverter, the amplitude of output voltage is Vs and the output power is P, then their corresponding values for a single phase full bridge inverter are ?

a) Vs, P

b) Vs/2, P

c) 2Vs, 2P

d) 2Vs, P

48. In an enhancement type MOSFET the output V-I characteristics has ?

a) only an ohmic region

b) only a saturation region

c) only ohmic region at 10 W voltage value followed by a saturation region at higher voltages

d)an ohmic region at large voltage values preceded by a saturation region at lower voltages

49. The energy gap in a semiconductor -

a) increases with temperature

b) remains constant

c) slightly increase with temperature

d) decrease with temperature
50. In an electronic circuit matching means -

a) connecting a high impedance directly to low impedance

b) selection of components which are compatible

c) transferring maximum amount of signal between different kinds of circuits.

d) RC coupled stages
51. P channel FETs are less superior than N channel FETs because

a) They have higher input impedance

b) They have high switching time

c) They consume less power

d) Mobility of electrons is greater than that of holes

52. Small increase in temperature in the CE connected transistor is the -

a) Increase in ICEO

b) Increase in ac current gain

c) Decrease in ac current gain

d) Increase in output resistance

53. An amplifier has a band width of 20 KHz and a midband gain of 50 without feedback. If a negative feedback of 1% is applied then bandwidth with feedback is -

a) 13. 3 KHz

b) 30KHz

c) 10KHz

d) 40KHz

54. The output of a class B amplifier -

a) is distortion free

b) consists of positive half cycles only

c) is like the output of a full wave rectifier

d) comprises short duration current pulses
55. An amplifier with negative feedback -

a) lowers its lower 3 dB frequency

b) raises its upper 3 dB frequency

c) increases its bandwidth

d) all of the above
56. What changes would be necessary in block C if FM signals are to be received -

a) Block becomes redundant

b) A FM detector would be required

c) A high frequency signal generator

d) An additional local oscillator will be needed

57. The main disadvantage of Diode-Transistor logic (DTL) is its-

a) greater speed

b) slower speed

c) average speed

d) none of the above

58. Time delay Dt in digital signals in an SIS O shift register is given by ?

a) Dt = N ? Fc

b) Dt = N ? 1/Fc

c) Dt = 1/N ? Fc

d) Dt = N ? 1/Fc
59. The output Qn is 1 in a JK flip flop and it does not change when clock pulse is applied) The possible combination of Jn and Kn can be ?

(y denotes don’t care)

a) y and 0

b) y and 1

c) 0 and y

d) 1 and y

60. Basic memory cell of dynamic RAM consists of ?

a) a flip flop

b) a transistor acting as a capacitor

c) a transistor

d) a capacitance
61. The 2′s complement of 10002 is ?

a) 0111

b) 0101

c) 1000

d) 0001

62. Master slave flip-flop is made up of ?

a) two flip flops connected in series

b) two flip flops connected in parallel

c) a debouncer circuit

d) a-D- latch
63. Number of nybbles making one byte is ?

a) 2

b) 4

c) 8

d) 16

64. The intrinsic impedance of free space-

a) is independent of frequency

b) decreases with increase of frequency

c) increases with increase of frequency

d) varies as square root of frequency
65. A system consists of 12 poles and 2 zeroes. Its high frequency asymptote in its magnitude plot has a slope of -

a) ?200 dB/decade

b) ?240 dB/decade

c) ?230 dB/decade

d) ?320 dB/decade

66. Considering the conditions-

1. High loop gain 2. Less ringing

3. Greater damping 4 Negative dB gain margin

System stability requirements would include

a) 1 and 3

b) 1, 2 and 3

c) 1 and 4

d) 2, 3 and 4

67. In the equatorial plane only Geosychronous satellite are launched because it is the only plane which provides ?

a) 24 hour orbit

b) stationary satellite

c) global communication

d) zero-gravity environs
68. Radio Broadcasting is an example of ?

a) space multiplexing

b) time multiplexing

c) frequency multiplexing

d) none of the above
69. PAM signals can be demodulation by using a ?

a) Low pass filters (LPE) alone

b) A Schmitt trigger followed by a LPF

c) A differentiator followed by a LPF

d) A clipper circuit by a LPF
70. In an FDM receiver channels can be separated by using ?

a) AND gates

b) Band pass

c) differentiation

d) Integration
71. The most common modulation system used for telegraphy is-

a) frequency shift keying

b) two ? tone modulation

c) pulse code modulation

d) single tone modulation
72. Use of varoctor diode in generation of modulated segial be-

a) FM generation only

b) 100AM generation only

c) PM generation only

d) both PM and AM generation

73. In colour picture tube shadow mask is used to-

a) reduce x-ray emission

b) ensure that each beam strikes only its own dots

c) increase screen brightness

d) provide degaussing for the screen
74. The circuit that separates composite video warefore from the sync pulses is-

a) the keyed AGC amplifar

b) a clipper

c) an integrator

d) a sawtooth current

75. Band width of microwaves is-

a) 1GHz -103 GHz

b) 1GHz ?100 GHz

c) 1 GHz ?10 GHz

d) 1 GHz ? 106 GHz

76. In transverse Magnetic mode-

a) no electric line is in direction of propagation

b) no magnetic line is in direction of propagation

c) bath magnetic & electric lines are is direction of propagation

d) neither magnetic nor electric lines in direction of propagation
77. Signal transmission in sky wave propagation is due to ?

a) Reforction of wave

b) Reflection of wave

c) Pierus through Inosphere

d) None

78. According to Barkhausen Criterion Phase shift of signal should be ?

a) 600

b) 900

c) 1800

d) 3600

79. The transmission does not have -

a) Partition noise

b) Flicker noise

c) resistance

d) Short noise

80. Varoctor diode has non linearity of -

a) capacitance

b) Inductance

c) Resistance

d) Is a linear device
81. Noise figure is calculated as ?

a) i/p signal to noise ratio X o/p signal to noise ratio

b) i/p S/N Ratio / O/P S/N Ratio

c) i/p S/N Ratio / O/P S/N Ratio X 100

d) i/p S/N Ratio + O/P S/N Ratio

82. You can determine quickly the effect of adding poles and zeros by ?

a) Nicholas chart

b) Nyquist plot

c) Bode plot

d) Root locus.
83. The polar plot of G(S) = intercepts real axis at w = wo. Then, the real part and wo are given by-

a) ?5, 1

b) ?2.5, 1

c) ?5,0-5

d) ?5, 2

84. Laplace transform F (s) of a function f (E) is given by

The initial and final values of F (t) will be respectively-

a) zero and 1

b) zero and 10

c) 10 and zero

d) 70 and 80

85. A satellite link uses different frequencies for receiving and transmitting in order to ?

a) avoid interference from terrestrial microwave links

b) avoid interference between its powerful transmitted signals and weak in coming signal

c) minimize free-space losses

d) maximize antenna gain
86. The first determining factor in selecting a satellite system is its-

a) EIRP

b) Antenna size

c) Coverage area

d) Antenna gain

87. Equalizing pulses in TV are sent during-

a) horizontal blanking

b) vertical blanking

c) the serrations

d) the horizontal retrace
88. The son seems to have ——– from his father a somewhat gloomy and moody manner-

a) washed

b) inherited

c) admired

d) attempt

60. Basic memory cell of dynamic RAM consists of ?

a) a flip flop

b) a transistor acting as a capacitor

c) a transistor

d) a capacitance
61. The 2′s complement of 10002 is ?

a) 0111

b) 0101

c) 1000

d) 0001

62. Master slave flip-flop is made up of ?

a) two flip flops connected in series

b) two flip flops connected in parallel

c) a debouncer circuit

d) a-D- latch
63. Number of nybbles making one byte is ?

a) 2

b) 4

c) 8

d) 16

64. The intrinsic impedance of free space-

a) is independent of frequency

b) decreases with increase of frequency

c) increases with increase of frequency

d) varies as square root of frequency
65. A system consists of 12 poles and 2 zeroes. Its high frequency asymptote in its magnitude plot has a slope of -

a) ?200 dB/decade

b) ?240 dB/decade

c) ?230 dB/decade

d) ?320 dB/decade

66. Considering the conditions-

1. High loop gain 2. Less ringing

3. Greater damping 4 Negative dB gain margin

System stability requirements would include

a) 1 and 3

b) 1, 2 and 3

c) 1 and 4

d) 2, 3 and 4

67. In the equatorial plane only Geosychronous satellite are launched because it is the only plane which provides ?

a) 24 hour orbit

b) stationary satellite

c) global communication

d) zero-gravity environs
68. Radio Broadcasting is an example of ?

a) space multiplexing

b) time multiplexing

c) frequency multiplexing

d) none of the above
69. PAM signals can be demodulation by using a ?

a) Low pass filters (LPE) alone

b) A Schmitt trigger followed by a LPF

c) A differentiator followed by a LPF

d) A clipper circuit by a LPF
70. In an FDM receiver channels can be separated by using ?

a) AND gates

b) Band pass

c) differentiation

d) Integration
71. The most common modulation system used for telegraphy is-

a) frequency shift keying

b) two ? tone modulation

c) pulse code modulation

d) single tone modulation
72. Use of varoctor diode in generation of modulated segial be-

a) FM generation only

b) 100AM generation only

c) PM generation only

d) both PM and AM generation

73. In colour picture tube shadow mask is used to-

a) reduce x-ray emission

b) ensure that each beam strikes only its own dots

c) increase screen brightness

d) provide degaussing for the screen

74. The circuit that separates composite video warefore from the sync pulses is-

a) the keyed AGC amplifar

b) a clipper

c) an integrator

d) a sawtooth current

75. Band width of microwaves is-

a) 1GHz -103 GHz

b) 1GHz ?100 GHz

c) 1 GHz ?10 GHz

d) 1 GHz ? 106 GHz

76. In transverse Magnetic mode-

a) no electric line is in direction of propagation

b) no magnetic line is in direction of propagation

c) bath magnetic & electric lines are is direction of propagation

d) neither magnetic nor electric lines in direction of propagation
77. Signal transmission in sky wave propagation is due to ?

a) Reforction of wave

b) Reflection of wave

c) Pierus through Inosphere

d) None

78. According to Barkhausen Criterion Phase shift of signal should be ?

a) 600

b) 900

c) 1800

d) 3600

79. The transmission does not have -

a) Partition noise

b) Flicker noise

c) resistance

d) Short noise

80. Varoctor diode has non linearity of -

a) capacitance

b) Inductance

c) Resistance

d) Is a linear device
81. Noise figure is calculated as ?

a) i/p signal to noise ratio X o/p signal to noise ratio

b) i/p S/N Ratio / O/P S/N Ratio

c) i/p S/N Ratio / O/P S/N Ratio X 100

d) i/p S/N Ratio + O/P S/N Ratio

82. You can determine quickly the effect of adding poles and zeros by ?

a) Nicholas chart

b) Nyquist plot

c) Bode plot

d) Root locus.
83. The polar plot of G(S) = intercepts real axis at w = wo. Then, the real part and wo are given by-

a) ?5, 1

b) ?2.5, 1

c) ?5,0-5

d) ?5, 2

84. Laplace transform F (s) of a function f (E) is given by

The initial and final values of F (t) will be respectively-

a) zero and 1

b) zero and 10

c) 10 and zero

d) 70 and 80

85. A satellite link uses different frequencies for receiving and transmitting in order to ?

a) avoid interference from terrestrial microwave links

b) avoid interference between its powerful transmitted signals and weak in coming signal

c) minimize free-space losses

d) maximize antenna gain
86. The first determining factor in selecting a satellite system is its-

a) EIRP

b) Antenna size

c) Coverage area

d) Antenna gain

87. Equalizing pulses in TV are sent during-

a) horizontal blanking

b) vertical blanking

c) the serrations

d) the horizontal retrace
88. The son seems to have ——– from his father a somewhat gloomy and moody manner-

a) washed

b) inherited

c) admired

d) attempt

89. Essayist works with words as sculptor with-

a) water

b) stone

c) air

d) hills

90. What is a collection of sheep called ?

a) bunch

b) flock

c) herd

d) comet

91. Join these sentences meaningfully by choosing the correct alternative from the following :

You can buy a book. You can read it.

a) and

b) nor

c) either

d) neither

92. What is the opposite of Asperity ?

a) gentility

b) superiority

c) kindness

d) clarity

93. The Election Commission functions under-

a) Ministry of Home Affairs

b) Ministry of Law

c) Prime Minister’s Secretariat

d) None of these
94. Article 352 of Indian Constitution needs to be revoked in case-

a) President’s Rule is to be imposed

b) Emergency is declared

c) Services of a Government servant are to be terminated without any enquiry

d) A political party of national level is to be banned
95. Radio-activity was first discovered by-

a) Becquerel

b) Madam Curie

c) Rutherford

d) Jenner

96. Ninth Plan in India ranges from-

a) 1995-2000

b) 1996-2001

c) 1997-2002

d) 1998-2003

97. How much electricity does India propose to generate through nuclear power by the year 2000 AD?

a) 5,000 MW

b) 10,000 MW

c) 15,000 MW

d) 20,000 MW

98. In which year did the fall of Bastille take place?

a) 1769

b) 1789

c) 1889

d) 1869

99. To form a quorum how many members of the Lok Sabha or Rajya Sabha should be present?

a) 1/10th of total membership

b) 1/6th of total membership

c) 1/4th of total membership

d) 1/5th of total membership
100. How may countries are non-permanent members of the Security Council?

a) 6

b) 7

c) 9

d) 10

Detailed Model Question Papers of BSNL TTA Exam here i am giving attachment