ISRO SCIENTISTS EXAM PREVIOUS PAPER 2008

1. How many NAND gates required to implement AB+CD+EF
ANS. 4
2. Transparent latch is seen in which type of flip flop
ANS. D flip-flop.
3. Odd parity generator uses which logic?
1. Digital 2.Analog 3. Sequential 4.none
4. One question based on Ripple counter.
5. Which diagram corresponds to D-flip-flop?
6. Which type of ADC is fastest?
ANS-flash/Parallel
7. Which one of the following is fastest read/writable memory?
1. PROM 2. EEPROM 3. Flash 4.none
8. In array programming which one is used

1. SISD 2. PISD 3. MISD 4. None
9. DSP uses the computer architecture derived from- 4 options. I don?t remember.
10. Solve ∫(t2∂(t-2)dt ?
11. they given the Bargraph and asked to find the voltage from it?
12.find laplace transform of e-2t?
ANS- 1/s+2.
13. Which one of the following is correct-4 options i dont remember?
14. Given VSWR=2 find reflection coefficient?
ANS-1/3
15.There are 2 seats to fill in a office a wife and husband came for the interview. For overall competition the probability of a wife to get selected is 1/7. The probability of husband to be selected is 1/5. Then find the probability of either wife/husband to get selected?
16.given matrix 4 -3 -3
1 0 1
-5 -5 x find x?
17. Find the differential equation of y=Ae3x+Be2x ?
18. one problem based on determination of resistance and one on inverting and non inverting Amplifier.
19. two Questions based on capacitor and one question based on inductance?
20. The Unit step signal is given to inductance what is the output?
21. what is the difference b/w switch and HUB?
1. switch avoids flooding
2. HUB stops broadcasting.
22. one question related to Energy signal and time signal (Depending on ampitude and Phase)?
23.a question related to switch to find resistance if switch is closed?
24.Aquestion based on SI and GE?
25.one question based on Enhancement MOSFET?
26. problem to find Iceo?
27.what is the advantage of using 4 diodes in Bridge rectifier compared to full wave rectifier?
28. Question related to PIV of bridge rectifier compared to Full wave rectifier?
29.Which one of the following has high I/p impedance
1. CC 2. CB 3. CE 4. None
30. one question based on FET And JFET?
31. where does operating point located in B type power amplifier?
32. which type of power amplifier is used in satellite communication
1.Amplitron 2. Klystron 3. Magnetron 4. TWT
33. de-emphasis is used to
1. Attenuate low signals.
2. Attenuate High signals.
3.Attenuate middle signals.
4. none.
34. Envelope detector is an …..? Ans- Asynchronous detector.
35.which one of the following produce modulated signal as i/p signal?
1. FM 2. PM 3. AM 4. None
36. they asked to find the gain? Given o/p power and i/p power.-4 options
37. Asked a question from EMfield on HEBD something.. i dont rem…?
38. find the modulous of 1+cosA+isinA?