Labels

Friday 3 January 2014

Steel Authority of India Limited (SAIL) Management Trainee Exam Electronics & Communication Model Paper

Steel Authority of India Limited (SAIL)
Management Trainee Exam 
Electronics & Communication Model Paper

Q.1. In a communication system, noise is most likely to get into the system
  • at the transmitter
  • in the channel
  • in the information source
  • at the destination
Q.2. When modulation frequency is doubled, the modulation index is halved, and the modulating voltage remains constant, the modulation system is
  • amplitude modulation
  • phase modulation
  • frequency modulation
  • angle modulation
Q.3. Impedance inversion may be obtained with
  • a short – circuited stub
  • an open – circuited stub
  • a quarter – wave line
  • a half – wave line
Q.4. HIGH frequency waves are
  • observed by the F2 layer
  • reflected by D layer
  • capable of use for long-distance communication on the moon
  • affected by the solar cycle
Q.5. Which one of the following terms does not apply to the Yagi-uda array
  • Good band width
  • Parasitic elements
  • Folded dipole
  • High gain
Q.6. A duplexer is used
  • to couple two different antennae to a transmitter without mutual interference
  • to allow one antenna to be used for reception or transmission without mutual interference
  • to prevent interference between two antennae when they are connected to receiver
  • to increase the speed of the pulses in pulsed radar
Q.7. Indicate which of the following system is digital
  • Pulse – Position modulation
  • Pulse – Code modulation
  • Pulse – Width modulation
  • Pulse – Frequency modulation
Q.8. A forward error correcting code corrects errors only
  • requiring partial retransmission of the signal
  • requiring retransmission of entire signal
  • using parity to correct to errors in all cases
  • requiring no part of the signal to be transmitted
Q.9. A typical signal strength received from a geosynchronous communication satellite is of the order of
  • a few milli watts
  • kilo watts 
  • watts
  • few pico watts
Q.10. Telephone traffic is measured
  • with echo canceller's
  • by the relative congestion
  • in terms of the grade of service
  • in erlangs
Q.11. Positive logic in a logic circuit is one in which
  • logic 0 and 1 are represented by 0 and positive voltage respectively
  • logic 0 and 1 are represented by negative and positive voltages respectively
  • logic 0 voltage level in higher than logic 1 voltage level
  • logic 0 voltage level is lower than logic 1 voltage level
Q.12. A half-adder can be made from
  • two NAND gates
  • a NOT gate and an OR gate
  • an AND gate and an OR gate
  • an AND gate and an X-OR gate
Q.13. Which of the following devices has its characteristics very close to that of an ideal current source.
  • Field effect transistor
  • Transistor in common base mode
  • Zener diode
  • MOSFET
Q.14. The main use of a common base transistor amplifier is
  • as voltage amplifier
  • current amplifier
  • for matching a high source impedance to a low load impedance
  • for rectification of a.c. signal
Q.15. A class-B amplifier is biased
  • Just at cut-off
  • nearly twice cut-off
  • at mid point of load line
  • so that IB equals jut IC
Q.16. If the peak transmitted power in a radar system is increased by a factor of 16, the maximum range will be increased by a factor of
  • 16
Q.17. A high PRF will (indicate the false statement)
  • make the returned echoes easier to distinguish from noise
  • make target tracking easier with conical scanning
  • increase the maximum range
  • have no effect of the range resolution
Q.18. A solution to the “blind speed” problem in a radar system is to
  • change the Doppler frequency
  • vary the PRF
  • use mono pulse
  • use MTI
Q.19. The number of active picture elements in a television image depends on
  • fly back time
  • CRT screen size
  • received band width
  • FB ratio of receiver antenna
Q.20. In a colour TV, the three primary colours are
  • red, orange and blue
  • red, blue and green
  • red, green and yellow
  • red, orange and green

4 comments: