# (Paper) ISRO Question Paper On May 2008

### ISRO Question Paper On May 2008

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) goto 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 aprocessor, then what will be the speed
improvement over nonpipelined 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 dont 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 flipflop 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<F1 (D)..