# Isro latest paper july 2010

1. An LTl system has the input signa| x(n).Which of the following sequence of operations is most appropriate to get output y(n) : x(n – MIL)’

ailnterpotation by L, Delay by M, Decimation by L

$ Delaj by M,Interpolation by L, Decimation by M

.jn”.irrruiion by L, Delay by M,Interpolation by L

i; trrr.rpolation by L, Decimation by L’ delay by M

consider a lorv passr andom processw ith a white noise power spectral density

Sx(ro)=N /2 where -ZnBSruo< ZnB

0 elsewhere

2. The Auto-correlation function Rx(t) is

a) 2NBsinc(2nB.r’1

b) nNBsinc(ZnBr)

c) NBsinc(ZnBt)

d) none ofthe above

3. Pole-zeroptotofadigitalfi|terisshownbelow,whatisthetype offilter?

a)Low Pass b) High Pass c) Band StoP d) AII Pass

4. Determinet hc DTFT of the sequenceyl nl : (n+l)u” ulnl’ laf < I ‘ u[nl is unit step sequence.

a) Y(d’) :l l(l – o c-ju’)t

b)Y(d’):ll(l+o”i’)’

.i via9 =c/r (l – o “-i’)t

d) none ofthe above

5. The function f(t) has the Fourier transform g(crl)’ The Fourier transform of g(t) is

^)

t(r) t ,n b\ t(-r.,r) | 7n

c) 2zr f(-to) d) none of the above

6. The purpose of Design for Test (DFT) process in ASIC design flow is

a) To capture functional errors

b) To capture manufacturing defects

c) To capture timing violations

d) For radiation mitigation

7. The coupling between the two inductors is increased from zero in the circuit shown. Which of the following statementsi s true?

Ll2A

a) The resonant frequency will increase and the Q will dccrcase

b) The resonant frequency and Q will both increase

c) The resonant frequency and Q will both decrease

d) The resonantf requencyw ill decreasea nd the Q will increase

8. A parallel plate capacitor of 100 pf having an air clielectric is charged to l0 kilovolts. It is then electrically isolated. The plates are pulled away from each other until the distance is ten times more than bcfore. Estimate the energy needed to pull the plates.

a) 0.O5.Ioules b) 50 .loules

a)

b)

c)

d)

c) 500 Joules d) -50.foules

9. How could Schroedinger’s cquation bc relcvant in the practical rlesign of a Catho6e- Ray Tube?

a) To optimize the colour quality

b) To optimize the picture sharpness

c) It is not relevant,b ecauset he CttT containsn o crystalline lattice structure

d) Its effects are negligible, as the electron wavelength is very small compared to the spot size

10. When compared with striptine, the major disadvantage of microstrip line is

a) Not amenable for printed circuit technique’

b) More expensive and complex to manufacture’

c) Bulkier and voluminous.

d) More likelY to radiate.

11. The disadvantage of single-stub matching as compared to double-stub matching, is that

a) The stub position has to be adjustable

b) Only shunt stub can be used

c) Only resistive load can be matched

d) Ut”f”l only in two wire transmission line

12. A charge Qz =8.854 xlg-e c is located in a vacuum atP2 (2’3’l)’ The force on Qz due to a charge QF4n xl0-3 C at Pr (2,2,1) is r\ Lr

a)a,Nb)-5.4a*+6.3a”-5.4a,Nc)5.4a–6.3a,-5.4a,Nd)None

13. If a material contains 1020 molecules/m3, each molecule having a moment of gSt* xl0-27 C-m parallel to an electric field of l0s V/m, then its dielectric constant is

*)2.2 b)z c) 4 d) 12

14. If every minor of order ‘r’ of a matrix ‘A’ is zero, then rank of ‘A’ is

a; greater than ‘r’ b) equal to ‘r’

.i l”r, than or equal to ‘r’ d) less than ‘r’

Which of the following is true

a) The procluct of the -eigenvalucos f a matrix is equal to the trace of the matrix

b)eigenvalues of a skew-symmetric matrix are real

c) A is a nonzero column matrix an6 B is a nonzcro row matrix, then rank of AB is one

d) A system.ofl inear non-homogeneoues quationsi s consistent if and only if the rank of the coefficient matrix is less than or equat to the rank of the augmented matrix

15. A unit step voltage travels from left to right along an infinite transmission line. It hits an inductive discontinuity at F0. What wilt be the waveform immediately to the left of the discontinuitY?

28 A lossy open stub having a length of ll32 wavelength, is approximately equivalent to

a) A small capacitor in shunt with a small resistor

b) A small capacitor in shunt with a large resistor

c) A small inductor in shunt with a small resistor

d) A targe inductor in shunt with a large resistor

a) Positive spike on a unit steP

c) Attenuated unit steP

29 Ampere’s law relates

a) Electric field and Charge

c) Magnetic field and Current

b) Unit step with reduced rise time

d) Magnified unit step

b) Electric field and Current

d) Magnetic field and Charge

16. Across which type of boundary does the electric field have a continuous tangential component?

b) Current free boundary

d) Charged boundary

b) n!/(s+a)”*r

d) 1/(s-a)”*l

17, the partial differential equation

b) Hyperbolic

d) Nature connote be Predicted

a) Charge free boundary

c) Any boundary

18. Laplace Transform of eu’tn is

a) n/(s-a)””1

c) n!/(s-a)n*r

For-oo<x<oo&-lcy<

*’#+1-yz){fi:ai’

a) parabolic

c) Elliptic {4

19. A communication channel with Additive White Gaussian Noise, has a bandwidth of 4 kHz and SNR of 3ldB.Its channel capacity is

a) 1.6 kbps b)20 kbps c) 32 kbPs d) 256 kbps

20. An angle modulated signal with caritr frequency o. :27t x 10s is described by the equations (t) : 10 cos( to.t + 5 sin(30002rt+) 10 sin(2000nt)) . what is the frequency deviation Af ?

a) 12387.32H2 b) 17500 Hz c) 20000 Hz d) 15000 Hz

21. A coaxial transmission line carrying an RF signal is perfectly matched to the load. Considert he cross-sectiono f the line, at a plane where the instantaneousv oltagei s at its maximum value. How will the curl of the E-field vary over this cross-section?

a) Increasesfr om the centert o the outer conductor

b) Decreasesfr om the center 6’tne outer conductor

c) Zero everywhere

d) Constant value proportional to the llF voltage