Steel Authority Of India Limited SAIL Model Questions Electronics, Electrical Engineering

Steel Authority Of India Limited

SAIL Model Questions

Electronics, Electrical Engineering

1. For emitter-coupled logic, the Switching speed is very high because

• Negative logic, is used
• The transistors are not saturated when Conducting
• Emitter-coupled transistors are used
• Multi- emitter transistors are used

2.Gray code for number 7 is

• 1100 
• 1001 
• 0110 
• 0100

3.10 bit A/D converters, the quantization error is given by (in Percent)

• 1 
• 2 
• 0.1 
• 0.2

4. If the memory chip size is 256*1 bits, then the number of chips required to make up 1K bytes of memory is

• 32 
• 24 
• c)12 
• 8

5. Given the decimal number — 19, an eight bit two’s complement representation is given by

• a)111O111O 
• b)111O11O1 
• c)111O1100 
• None of these

6. A 4-bit synchronous Counter Uses flip-flops with propagation delay time of 25 ns each. The maximum possible time required for change of state will be

• 25 ns 
• 50 ns 
• 75 ns 
• 100 ns

7. An electromagnetic Wave incident on a perfect Conductor is:

• Entirety reflected 
• Fully transmitted
• Partially transmitted 
• None of these

8. The characteristic impedance of a lossless transmission line is given by

• Z= √ LC 
• Z= √C/L 
• Z= LC 
• Z = √L/C

9. A lossless line of 50 ohms is terminated in a load of 100 ohms resistive The VSWR is

•  1:2 
• 2:1 
• 4:1 
• 1:4

10. Which of the following does not exist in waveguides

• TE waves 
• TM waves
• TE waves and TM waves 
• TEM waves

11. carriers of 2GHz and 4GHz respectively are frequency modulated by a signal of 10 KHz, such that bandwidth of the FM signal in the two cases are same. The peak deviation in the two cases are in the ratio of

• 1:8 
• 1:2 
• 2:1 
• 1:1

12. The bandwidth required for QPSK modulated channel is

• Twice the BW of BPSK 
• Equal to BPSK
• Equal to FSK 
• Half of the BW of BPSK

13. Magic T is

• Four part junction 
• Two part junction
• Three part junction 
• It is not junction

14. Diplexer is made of

• Only receive filter 
• Only transmit filter
• Only circulator 
• Both receive filter and transmit filter

15. If the short circuit and open circuit impedance of a line are 5 and 20Ω respectively the characteristic impedance is given by

• 100Ω 
• 10Ω 
• 15Ω 
• 10000Ω

16. The input impedance of short circuited line of length I where λ/4<1<λ/2, is

• Capacitive 
• Inductive 
• Resistive 
• None of these

17. Maximum coding gain in

• Block Codes 
• Convolution Codes
• Turbo Codes 
• RS Codes

18. Noise figure of an amplifier depends on

• Bandwidth 
• Output power 
• Power input 
• none of the above

19. BCH code belongs to

• Block Codes 
• Convolution Codes
• Turbo Codes 
• None of the above

20. When a carrier is phase modulated, with an integrated modulating signal, the resultant is

• Phase modulated signal 
• Frequency modulated signal
• Amplitude modulated signal 
• QPSK modulated signal

21. A satellite orbiting in 600 km orbit transmits 5 GHz frequency. The Doppler shift observed at the ground station, when the satellite is over head of the station is

• Zero 
• Maximum 
• Infinity 
• None of the above

22. A communication channel disturbed by additive white Gaussian noise has a bandwidth of 4 kHz and SNR of 15. The highest transmission rate that such a channel can support (in k-bits/seis

• 16 
• 1.6 
• 3.2 
• 60

23. A dual directional Coupler is connected in a microwave reflectometer measurement setup. The reading of the Power meter in the forward direction is 100 mw and in the reverse direction 4 mw. The VSWR is

• 4 
• 0.4 
• 1.5 
• 10

24. Linear amplifier with a gain of 30dB is fed with 1.0 μW power, the output Power of the amplifier

• 1.0 W 
• 0 dBm 
• 3O dBm 
• -3O dBm

25. 10 Watt RF Power is transmitted with a circular polarized antenna having gain of 10dB. A receiving antenna has vertical polarization. The path loss is 100dB. The receiving signal is

• -83dBW 
• -8OdBW 
• -86dBW 
• +8OdBW