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 AӨB (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/√2
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 12Ώ and the effective resistance when one resistor broke is 18Ώ 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) δ(t) represents impulse then ∫( δ(t) cos 2t )dt with limits 0 to infinity is
a) 1, b) -1 c) infinity d ) 0
53) ∫1/(x√(x2-a2)) dx is
Sample questions asked in ISRO board (ECE)
1) How does a satellite communication work?
2) Why numerical methods used in research?
3) Hell lot of questions in TV engineering like horizontal and vertical frequencies, what will happen if they are reversed, interlaced scanning, PAL and some other questions.
4) Basic digital questions
5) Basic communications like SSB, AM, FM, VSB and what will happen if AM and FM is interchanged in TV transmission.
6) Some questions on project.
Main model of technical question in exam are
Direct theory question.
Direct numerical problem.
Indirect theory and numerical problem.
Graph based questions.
Assertion and reasoning type
Block diagram based (control theory)
The minimum number of edges in a connected cyclic graph on n vertices is
a) n-1 b) n c) n+1 d)none of these
2.
A full binary tree with n non leaf nodes contains
a) n nodes b) log n nodes c)2n-1 nodes d)2n nodes
3.
The time complexity of shell sort
a) O(n) b) O(log n) c) O(n 1.2 ) d)O(n2)
4.
The time taken to insert an element after an element pointed by some pointer
a) O(1) b) O(log n) c) O(n) d) O(nlogn)
5.
what is the name given to the first generation computer?
a) Binary language b)Machine language c)Assembly language
6.
The root directory of a disk should be placed
a) at a fixed address in main memory
b) at a fixed location on disk
c) anywhere on disk.
7.
A top down parser generates
a) right most derivation
b) left most derivation
c) right most derivation in reverse
d) left most derivation in reverse
8.
what is the name of the OS that reads and reacts in terms of actual time?
a)batch system
b)time sharing
c)real time
9.
FDDI is a
a)ring network
b)star network
c)mesh network
10.
Computer memory consists of
a)ROM
b)PROM
c) RAM
d)all the above
ISRO SAMPLE TEST PAPER ON 15th JULY2006 AT DELHI
Hi to all,
. 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 Transform 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) ?(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 ?/4a) 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 rebutting 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/?2
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) Duplexer is a
a) circulatory only b)only transmitter filter c) only receiver filter
d) both transmitter and receiver filter
52) ?(t) represents impulse then ?( ?(t) cos 2t )dt with limits 0 to infinity is
a) 1, b) -1 c) infinity d ) 0
53) ?1/(x?(x2-a2)) dx is
A)cosec2x
1) Moore model of DFF?
2) Which of the following filter has steep roll-off characteristics?
(A) Butterworth filter (B) Chebyshev filter (C) Bessel filter (D)--
ans: B
3)The architecture of DSP processor---------
(A) Havard (B) Von neumann (C)...(D)..
ans: A
4)If the input frequency to a 6 stage ripple counter is 1000MHz then output frequency at 6th stage_______
5)Minimum number of 2 input NAND gates required to realise the fn. AB'+CD'+EF'
ans: 6
6)What will exit() fn. in C will do?
7) go to command in C will cause the program to jump to----
ans: Label
8)VSWR is given then asked to find out reflection coefficient
9)The relation between power in FM signal and modulation index--------
10)If two signals are AM modulated with modulation indices of 0.3 and 0.4 what will be the modulation index of combined signal?
ans: Calculate using 1/M=(1/m1)+(1/m2)
11)If n stage pipelining is used in a processor, then what will be the speed improvement over non pipelined processor?
(A) same (B) n (C) n! (D) 2n
12) One circuit is given (That was a Voltage Doubler using op-amp) and asked to Identify that...
13) Which one of the following memory has fastest write time?
(A) Flash (B) EEPROM (C) EPROM (D) None of these
14) In EEPROM data is stored in____
(A) Cross coupled Latch (B) Capacitor (C) floating gate transistor (D)--
15) Which technology is faster?
(A) Bipolar (B) MOS (C) CMOS (D) ..
16)Memory access time, cache access time , hit ratio are given, Asked to find out Average memory access time
17) If the probability of getting a job for A is 1/3 and the probability of getting a job for B is 1/4 then the probability of getting a job for A or B will be____?
18)One transfer fn As4 + Bs3 + Cs2 +D=0 (I don't remember the values of A,B,C,D ) is given, Asked to find out whether the system is____
(A) Stable (B) Unstable (C) Marginally Stable
19) For implementing D flip flop using RS flip flop, the extra component needed is____
(A) AND gate (B) OR gate (C) NOT gate (D) NOR gate
20)The output of an 8 bit DAC is 1Volt when the input is 00110010, then the full scale output of the same DAC will be____
ans: 5.1 V (Hint: 1/50*255)
21)Fastest ADC is___
(A) SAR (B) sigma- delta (C) flash (D)...
22)The operating point of Class-B amplifier will be at_____
(A) exactly at cut-off region (B) inside saturation region (C) inside cut-off region (D) middle of active region
23)For an N bit ADC , the number of comparators needed___
(A) N (B) 2N (C) 2N -1 (D) 2N-1
24)De-emphasis circuit is used for_______
ans: Attenuating high frequency components
25)The laplace transform of e-2t _____
Ans: 1/(s+2)
26)The magnitude of 1+cos x+j sin x____
Ans: 2 cos (x/2)
27) A circuit is given in which the capacitor (1uF) is initially charged to 12V , At t = 0, one switch is closed so that another capacitor of capacity 1.5uF comes in parallel with the first capacitor, then in steady state what will be the voltage across them? ( Visualize the circuit , as I can not draw the circuit since the editor is not supporting it)
28)Alpha of a transistor=0.99, Ico=1uA, Ie=1 mA, Ic=?
29)If the input given to an inductor is delta(t) (ie: =1 when t=0 and ,=0 otherwise) then the current will be___
(A) infinity (B) -infinity (C) 1 (D) 0
30) For implementing Band pass filter using High pass filter (Cutt off freq=Fh) and Low pass filter (cutt off freq= Fl)_____
(A)Fh=Fl (B) Fh>Fl (C) Fh
Ans: Fh
31)In the Enhancement type MOSFET the gate to source voltage Vs drain current characteristics will be____
Ans: Drain current Increases as Vgs increases in active region
32)In a johnson counter, How many state have to be changed to increment the count from 0100 to 0111?
33)Odd parity generator is____
Ans: XNOR gate
34)A circuit using op-amp was given, the question was to calculate output offset voltage___
Ans: Vo(off)=Vin(off)*(1+Rf/R1)
35)Antialiasing filter is_____
(A) Digital filter (B) Analog filter (C) Can be Analog or digital (D) RC filter