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?
Showing posts with label ISRO Scientist Electronics. Show all posts
Showing posts with label ISRO Scientist Electronics. Show all posts
Tuesday, April 21, 2009
ISRO Scientist SC- Electronics- 2006
1. If sampling frequency doubles then
a) Quantization noise decreases
b) Quantization density decreases
c) Quantization noise increases
d) Quantization density increases
2. Two signals of 2GHz and 4GHz are frequency modulated on same carrier 10 GHz. Find the ratio of frequency deviation if band widths of both are equal.
a) 1:2 b)2:1 c) 1:1 d) 1:4
3. Gray code of 111 is
4. 3X512+7X64+5X8+3 then value in binary form contains _______ number of 1’s.
a) 7 b) 6 c) 9 d) none
5. The 2’s compliment of decimal number 19 in 8-bit system is
a) 11101101
6) The high gain codes are
a) Turbo codes b) BCH codes c) R-S codes
7) BCH codes are of the type________
a) Convolutional type b) c)
8) Time constant of LC circuit is
a) L/R b) L/R2 c) RL
9) If R is doubled and C is halved then frequency of series RLC circuit is
10) The solution for the equation (D2+4) y=sin2x is
11) Laplace Tramsform of sin3x is
12) The Z-transform for the series is
X [n] = { 7; n= -1
{5 n=0
{ 1 n=1
{0 else
13) The magic Tee is a
a) 4 port tee b) c)
14) The register which holds the address of the next instruction is
a) Program counter b) c)
15) The antenna gain is given by...............?
a16) The satellite is in 630km orbit and transmitting at a frequency 5 MHz, when satellite is on your head the Doppler shift is--------
a) b) c) 0 d)
17) The impedance of a lossless transmission line is
a) v(L/C)
18) A 50?line with load impedance 100? the VSWR is
19) In a waveguide measurement, the forward power is 10mW, the reverse power is 1mW then VSWR is _____________
20) Transmitted power is 100W, gain of the transmitter antenna is 30 dB and the path loss is 50 dB then received power is
21) When transmitted power is 100mW and the path loss 100 dBm then received power is
a) -80 dBm
22) When a em wave is incident normally on a perfect conductor then
a) Totally reflected b) partially reflected
c) Totally transmitted d) none.
23) Zsc =100? Zoc =1? then Zo is
a) 1? b) 10? c)___d)__
24) When the operating wavelength of line is ?/4
a) Capacitive b) inductive c) ____ D) none
25) The value of L if source is 50V AC of 10 KHz frequency and current is 7.96 A.
a) ____
26) The resonant frequency is 50MHz bandwidth 100 KHz then Q factor is
a) ______ b)_______ c)…..
27)The Q factor of a series RLC circuit is
a)……b)……
28) Q value of a parallel RLC circuit is ________
a)……b)….
29) If the lines x+y+3=0, x-2y+7=0, 2x+ky+5=0 are required to be concurrent then the value of k is___ a) ___ b)…..
30) The vectors i-2j+k, 2i+3j-k,R are the complete, then r is given by ______
31) If a satellite revolving with angular velocity w and the velocity is v then
Curl v is _______
a) w b) 2w c) w 2 d) …..
32) If each stage amplifier contains 10dB gain the figure of merit of 2-stages is
Given by ……
33) The maximum rate possible in kbps if F=15 and bandwidth is 4 KHz is…….
34) The maximum time allowed for each flip flop for a ripple counter of mod-1024 , if clock given to it is 1MHz is ……..
35) The maximum time allowed time for each flip flop for a mod 10 synchronous counter if each flip flop delay is 25ns.
a) 25 ns b) 50 ns c) 100 ns d) none
36) The high speed for CML gate is due to operating it in --------- region.
a) non saturation
37)In a micro processor the wait states are inserted to
a) make the processor to wait during DMA operation
b) make the processor to wait during an interrupt processing
c) make the processor wait during a power shutdown.
d) interface the slow peripherals to the processor.
38) In a digital voltmeter the ADC’s used are of type
1. successive 2.flash type 3. Dual slope
in ascending order of time is
1. a) 2,1,3 b) 1,2,3 c) 3,1,2 d) none
39) The number of NAND gates are required to implement A?B (XOR), assuming compliments
not available ………….
40) The resolution for a DAC is given by 0.4% then no. of bits of DAC is
a) 8- bits
41) The chip capacity is 256 bits, then the no.
of chips required to build 1024 B memory
Is……….
1. a) 32 b) 16 c) 15)
42) Which of the following are correct?
1. A flip-flop is used to store 1-bit of information
2. Race around condition occurs in JK flip flop when both the inputs are 1
3. Master slave flip flop is used to store 2 bits of information
4. A transparent latch consists of a D- flip flop
a) 1, 2,3 b) 1,3,4 (ANS) c)1,2,4 d) 2,3,4
43) The bit rate of a QPSK compared to BPSK is
a)half b) double c) same
44) There are 5 red balls and 5 black balls in a box. The probability to select 2 balls one after other without reputting is,
a) 2/9 b) 1/90 c) 11/90 d) none
45) The rms voltage is obtained by multiplying peak by a factor
a) 1/v2
46) H(s)=S/(S+a) is a transfer function of ______
a) LPF b) Notch c) BPF d) HPF
47) Resistance of a 2 parallel resistors is 12? and the effective resistance when one resistor broke is 18? then the value of resistance in another is_________
48)The output of a phase modulator when input applied is integrating signal is
a)FM b) AM c) PM d) none
49) For a transformer the losses which vary with load are
a) core losses b) copper losses c) Hysterises losses d) none.
50) The waves which cannot be transmitted in waveguide are
a) TE b) TEM c) TM d) none
51) Diplexer is a
a) circulator only b)only transmitter filter c) only receiver filter
d) both transmitter and receiver filter
52) d(t) represents impulse then ?( d(t) cos 2t )dt with limits 0 to infinity is
a) 1, b) -1 c) infinity d ) 0
53) ?1/(xv(x2-a2)) dx is
A)cosec2x
a) Quantization noise decreases
b) Quantization density decreases
c) Quantization noise increases
d) Quantization density increases
2. Two signals of 2GHz and 4GHz are frequency modulated on same carrier 10 GHz. Find the ratio of frequency deviation if band widths of both are equal.
a) 1:2 b)2:1 c) 1:1 d) 1:4
3. Gray code of 111 is
4. 3X512+7X64+5X8+3 then value in binary form contains _______ number of 1’s.
a) 7 b) 6 c) 9 d) none
5. The 2’s compliment of decimal number 19 in 8-bit system is
a) 11101101
6) The high gain codes are
a) Turbo codes b) BCH codes c) R-S codes
7) BCH codes are of the type________
a) Convolutional type b) c)
8) Time constant of LC circuit is
a) L/R b) L/R2 c) RL
9) If R is doubled and C is halved then frequency of series RLC circuit is
10) The solution for the equation (D2+4) y=sin2x is
11) Laplace Tramsform of sin3x is
12) The Z-transform for the series is
X [n] = { 7; n= -1
{5 n=0
{ 1 n=1
{0 else
13) The magic Tee is a
a) 4 port tee b) c)
14) The register which holds the address of the next instruction is
a) Program counter b) c)
15) The antenna gain is given by...............?
a16) The satellite is in 630km orbit and transmitting at a frequency 5 MHz, when satellite is on your head the Doppler shift is--------
a) b) c) 0 d)
17) The impedance of a lossless transmission line is
a) v(L/C)
18) A 50?line with load impedance 100? the VSWR is
19) In a waveguide measurement, the forward power is 10mW, the reverse power is 1mW then VSWR is _____________
20) Transmitted power is 100W, gain of the transmitter antenna is 30 dB and the path loss is 50 dB then received power is
21) When transmitted power is 100mW and the path loss 100 dBm then received power is
a) -80 dBm
22) When a em wave is incident normally on a perfect conductor then
a) Totally reflected b) partially reflected
c) Totally transmitted d) none.
23) Zsc =100? Zoc =1? then Zo is
a) 1? b) 10? c)___d)__
24) When the operating wavelength of line is ?/4
a) Capacitive b) inductive c) ____ D) none
25) The value of L if source is 50V AC of 10 KHz frequency and current is 7.96 A.
a) ____
26) The resonant frequency is 50MHz bandwidth 100 KHz then Q factor is
a) ______ b)_______ c)…..
27)The Q factor of a series RLC circuit is
a)……b)……
28) Q value of a parallel RLC circuit is ________
a)……b)….
29) If the lines x+y+3=0, x-2y+7=0, 2x+ky+5=0 are required to be concurrent then the value of k is___ a) ___ b)…..
30) The vectors i-2j+k, 2i+3j-k,R are the complete, then r is given by ______
31) If a satellite revolving with angular velocity w and the velocity is v then
Curl v is _______
a) w b) 2w c) w 2 d) …..
32) If each stage amplifier contains 10dB gain the figure of merit of 2-stages is
Given by ……
33) The maximum rate possible in kbps if F=15 and bandwidth is 4 KHz is…….
34) The maximum time allowed for each flip flop for a ripple counter of mod-1024 , if clock given to it is 1MHz is ……..
35) The maximum time allowed time for each flip flop for a mod 10 synchronous counter if each flip flop delay is 25ns.
a) 25 ns b) 50 ns c) 100 ns d) none
36) The high speed for CML gate is due to operating it in --------- region.
a) non saturation
37)In a micro processor the wait states are inserted to
a) make the processor to wait during DMA operation
b) make the processor to wait during an interrupt processing
c) make the processor wait during a power shutdown.
d) interface the slow peripherals to the processor.
38) In a digital voltmeter the ADC’s used are of type
1. successive 2.flash type 3. Dual slope
in ascending order of time is
1. a) 2,1,3 b) 1,2,3 c) 3,1,2 d) none
39) The number of NAND gates are required to implement A?B (XOR), assuming compliments
not available ………….
40) The resolution for a DAC is given by 0.4% then no. of bits of DAC is
a) 8- bits
41) The chip capacity is 256 bits, then the no.
of chips required to build 1024 B memory
Is……….
1. a) 32 b) 16 c) 15)
42) Which of the following are correct?
1. A flip-flop is used to store 1-bit of information
2. Race around condition occurs in JK flip flop when both the inputs are 1
3. Master slave flip flop is used to store 2 bits of information
4. A transparent latch consists of a D- flip flop
a) 1, 2,3 b) 1,3,4 (ANS) c)1,2,4 d) 2,3,4
43) The bit rate of a QPSK compared to BPSK is
a)half b) double c) same
44) There are 5 red balls and 5 black balls in a box. The probability to select 2 balls one after other without reputting is,
a) 2/9 b) 1/90 c) 11/90 d) none
45) The rms voltage is obtained by multiplying peak by a factor
a) 1/v2
46) H(s)=S/(S+a) is a transfer function of ______
a) LPF b) Notch c) BPF d) HPF
47) Resistance of a 2 parallel resistors is 12? and the effective resistance when one resistor broke is 18? then the value of resistance in another is_________
48)The output of a phase modulator when input applied is integrating signal is
a)FM b) AM c) PM d) none
49) For a transformer the losses which vary with load are
a) core losses b) copper losses c) Hysterises losses d) none.
50) The waves which cannot be transmitted in waveguide are
a) TE b) TEM c) TM d) none
51) Diplexer is a
a) circulator only b)only transmitter filter c) only receiver filter
d) both transmitter and receiver filter
52) d(t) represents impulse then ?( d(t) cos 2t )dt with limits 0 to infinity is
a) 1, b) -1 c) infinity d ) 0
53) ?1/(xv(x2-a2)) dx is
A)cosec2x
ISRO Scientist SC- Electronics
Pattern of Exam Questions
1.if diameter of antenna increase by 3,then gain of the antenna will be,
a.increase by 3
b.decrease by 3
c.no change in gain
2.more number of problem from zener diode...
3.vector sum questions
4. problems from parallel and series connection of resistor...
5. The value of this determinant
1 a b+c
1 b a+c
1 c b+a
ans: zero
6. solve (D2+16)y=cos4x
ans:y= 4x+Bsin 4x+x/8 sin 4x
7.in half adder circuit... what are the gates used?
8.conversion problem fron digital systems octal to binary
66.3(octal) to binary
9.formula for cos ax=? in terms of expo
10.what is the o/p of 4:1 MUX?
11.enegry stored in variable capacitor and constant voltage...
12.WHICH OF THE FOLLOWING OSILLATOR HAVE HIGH ACCURACY? refer all the osillator
13.they given a circuit,which convert binary to.....?
a. BCD
b.excess 3
c.gray
d.none of these
14.output impedance of ideal op-amp is...? ans: zero.
15.which one of the following is correct formula? choice are simple formula like V=IR,F=eE, etc...)
16. from RLC ckt
This is based on the past experience of various candidates.
1.if diameter of antenna increase by 3,then gain of the antenna will be,
a.increase by 3
b.decrease by 3
c.no change in gain
2.more number of problem from zener diode...
3.vector sum questions
4. problems from parallel and series connection of resistor...
5. The value of this determinant
1 a b+c
1 b a+c
1 c b+a
ans: zero
6. solve (D2+16)y=cos4x
ans:y= 4x+Bsin 4x+x/8 sin 4x
7.in half adder circuit... what are the gates used?
8.conversion problem fron digital systems octal to binary
66.3(octal) to binary
9.formula for cos ax=? in terms of expo
10.what is the o/p of 4:1 MUX?
11.enegry stored in variable capacitor and constant voltage...
12.WHICH OF THE FOLLOWING OSILLATOR HAVE HIGH ACCURACY? refer all the osillator
13.they given a circuit,which convert binary to.....?
a. BCD
b.excess 3
c.gray
d.none of these
14.output impedance of ideal op-amp is...? ans: zero.
15.which one of the following is correct formula? choice are simple formula like V=IR,F=eE, etc...)
16. from RLC ckt
This is based on the past experience of various candidates.
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