Q.1

If xk = 2k for k ≤ 0 and = 0 for k > 0 X(z) = 2/(2 - z).

  • True
  • False
Q.2

If p is the probability of success and q is the probability of failure, then the probability that there are r successes in n trails is

  • ncr pr qn - r
  • ncr pn - r qr
  • ncr pr qn + r
  • ncr pn qn - r
Q.3

Consider the following statements

  1. If ensemble and time averages of a random process are identical, the process is ergodic.
  2. If ensemble and time average of a random process are not identical, the process is ergodic.
  3. An ergodic process is stationary.
  4. A stationary process is necessarily ergodic.
Which of the above statements are correct?
  • 1 only
  • 1 and 3 only
  • 1, 3 and 4 only
  • 1 and 4 only
Q.4

In a oscillator, a sine wave generator starts at t =It consist of

  • Unity for t > 0
  • 2∪(t) - 1
  • Pure sine wave
  • Pure cosine wave
Q.5

The theoretical power of white noise is

  • zero
  • finite
  • depend upon frequency of signal
  • infninite
Q.6

If f(t) ↔ F(jω), f(- t) ↔

  • - F(jω)
  • F(- jω)
  • F(jω)
  • 0.5 F(jω)
Q.7

Assertion (A): When a function f(t) is represented as exponential Fourier series, the set of complex coefficients Fn is called frequency spectrum of f(t)

Reason (R): Frequency spectrum is also called line spectrum.

  • Both A and R are correct and R is correct explanation of A
  • Both A and R are correct but R is not correct explanation of A
  • A is true, R is false
  • A is false, R is true
Q.8

The area of an impulse is

  • 1
  • 0
  • any finite value
Q.9

In plotting line spectrum

  • a graph of complex number Fn versus frequency is plotted
  • a graph of |Fn| versus frequency is plotted
  • a graph of the angle of Fn versus frequency is plotted
  • two graphs viz |Fn| versus frequency and the phase angle of Fn versus frequency are plotted
Q.10

To plot frequency spectrum we draw two graphs viz |Fn| versus frequency and φn versus frequency.

  • True
  • False
Q.11

If f(t) is an even function, the coefficients Fn in the exponential form of Fourier series

  • are real
  • are imaginary
  • are complex
  • may be real or imaginary
Q.12

(sI - A)-1 is equal to

  • adj (sI - A)/det (sI - A)
  • det (sI - A)/adj(sI - A )
  • [adj (sI - A)] [det(sI - A)]
  • none of the above
Q.13

For a periodic waveform, the power spectral density and correlation function form

  • a Laplace transform pair
  • a Fourier transform pair
  • either (a) or (b)
  • neither (a) nor (b)
Q.14

Assertion (A): Laplace transform can be used to evalute integrals.

Reason (R): Laplace transform can be used to solve differential equations.

  • Both A and R are correct and R is correct explanation of A
  • Both A and R are correct but R is not correct explanation of A
  • A is true, R is false
  • A is false, R is true
Q.15

The peak factor is

  • rms value/peak value
  • rms value/average value
  • peak value/rms value
  • peak to peak value/rms value
Q.16

Assertion (A): The function kest with both σ and ω positive and s > 0 depicts a sinusoid whose amplitude increases with time.

Reason (R): If σ =kest becomes a sinusoid.

  • Both A and R are correct and R is correct explanation of A
  • Both A and R are correct but R is not correct explanation of A
  • A is true, R is false
  • A is false, R is true
Q.17

If F(jω) is the Fourier transform of f(t), then

  • £ f(- t) = F(jω)
  • £ f(- t) = F* (jω)
  • £ f(- t) = F(- jω)
  • £ f(- t) = F* (- jω)
Q.18

Assertion (A): Transient analysis uses Laplace transformation.

Reason (R): Laplace transform method is suitable for solution of integro differential equations.

  • Both A and R are correct and R is correct explanation of A
  • Both A and R are correct but R is not correct explanation of A
  • A is true, R is false
  • A is false, R is true
Q.19

The minor Mij of an n x n matrix is the determinant of (n -x (n -matrix formed by deleting the ith row and j the column of n x n matrix.

  • True
  • False
Q.20

For matrix A, A-1 A = 1

  • True
  • False
Q.21

e-3t is a

  • energy signal
  • power signal
  • Both (a) and (b)
  • none
Q.22

For a Gaussian process, auto-correlation sequence also implies that

  • statistical independence
  • statistical dependence
  • ergodic process
  • all
Q.23

Assertion (A): A half cycle of sine wave can be expressed as sum of sine wave and another sine wave shifted by T/2 where T is the time period.

Reason (R): The function u(t - t0) - u(t - t0 - T) is a gate function occuring at t = t0 and of duration T.

  • Both A and R are correct and R is correct explanation of A
  • Both A and R are correct but R is not correct explanation of A
  • A is true, R is false
  • A is false, R is true
Q.24

Assertion (A): Heaviside partial expansion gives a simple procedure to find inverse Laplace transform of the terms having a complex conjugate pair of roots.

Reason (R): If I(s) = P(s)/Q(s) and all roots of Q(s) = 0 are simple, i(t) will have terms with exponentials having real exponents only.

  • Both A and R are correct and R is correct explanation of A
  • Both A and R are correct but R is not correct explanation of A
  • A is true, R is false
  • A is false, R is true
Q.25

The energy of highest value of Autocorrelation of a functioncospt is

  • 50
  • 10
  • 200
  • zero
Q.26

If p is the probability of success and q is the probability of failure, then the probability that there are r successes in n trails is

  • ncr pr qn - r
  • ncr pn - r qr
  • ncr pr qn + r
  • ncr pn qn - r
Q.27

Which one of the following is correct? Energy of a power signal is

  • finite
  • zero
  • infinite
  • between 1 and 2
Q.28

If xk = ak and k ≥ 0
X(z) = (1 - az-1)-1 with |a| < |z|

  • True
  • False
Q.29

The function δ' (t-b) is

  • a step function originating at t = b
  • an impulse function originating at t = b
  • a unit doublet originating at = t - b
  • none of the above
Q.30

An impulse train is

  • a number of pulses
  • a number of pulses spaced from each other
  • a number of pulses all originating together
  • none of the above
Q.31

For formation of state equations, the inductors and current sources

  • should be in tree
  • should be in cotree
  • may be in tree or cotree
  • should be in both tree and cotree
Q.32

If u is input, y is output and a, b are constants, the system y = au + b

  • is linear
  • is nonlinear
  • may be linear or nonlinear dependig on values of a and b
  • may be linear or nonlinear depending on value of u
Q.33

In RLC circuits the state variables generally selected are

  • voltages across capacitors
  • currents through resistances and voltages across capacitors
  • currents through resistances and capacitances
  • currents through inductances and voltages across capacitances
Q.34

Assertion (A): Transient periods are of short duration but can result in dangerously high voltages and currents.

Reason (R): Circuit equations in transient analysis are integral differential equations.

  • Both A and R are correct and R is correct explanation of A
  • Both A and R are correct but R is not correct explanation of A
  • A is true, R is false
  • A is false, R is true
Q.35

If f(t) =F(jω) =

  • 2p
  • p
  • 2pδ (p)
  • pδ (ω)
Q.36

Auto correlation function

  • is an even function of t
  • is an odd function of t
  • may be an even or odd function of t
  • is both an odd and even function of t
Q.37

If the value of

  • cannot be determined
  • 0
  • 1
Q.38

For the signal in the given figure the Fourier transform is Then the Fourier transform of the signal in the given figure

Q.39

Assertion (A): If

Reason (R): Displacement in time domain by T becomes multiplication by e-st in s domain.

  • Both A and R are correct and R is correct explanation of A
  • Both A and R are correct but R is not correct explanation of A
  • A is true, R is false
  • A is false, R is true
Q.40

If the value of

  • cannot be determined
  • 0
  • 1
Q.41

The minor Mij of an n x n matrix is the determinant of (n -x (n -matrix formed by deleting the ith row and j the column of n x n matrix.

  • True
  • False
Q.42

The following table gives some time functions and the Laplace transforms

Of these correctly matched pairs are

  • 2 and 4
  • 1 and 4
  • 3 and 4
  • 1 and 2
Q.43

Auto correlation function

  • is an even function of t
  • is an odd function of t
  • may be an even or odd function of t
  • is both an odd and even function of t
Q.44

If the value of

  • cannot be determined
  • 0
  • 1
Q.45

The following table gives some time functions and the Laplace transforms

Of these correctly matched pairs are

  • 2 and 4
  • 1 and 4
  • 3 and 4
  • 1 and 2
Q.46

Assertion (A): Transient periods are of short duration but can result in dangerously high voltages and currents.

Reason (R): Circuit equations in transient analysis are integral differential equations.

  • Both A and R are correct and R is correct explanation of A
  • Both A and R are correct but R is not correct explanation of A
  • A is true, R is false
  • A is false, R is true
Q.47

The following table gives some time functions and the Laplace transforms

Of these correctly matched pairs are

  • 2 and 4
  • 1 and 4
  • 3 and 4
  • 1 and 2
Q.48

Assertion (A): If

Reason (R): Displacement in time domain by T becomes multiplication by e-st in s domain.

  • Both A and R are correct and R is correct explanation of A
  • Both A and R are correct but R is not correct explanation of A
  • A is true, R is false
  • A is false, R is true
Q.49

Assertion (A): If

Reason (R): Displacement in time domain by T becomes multiplication by e-st in s domain.

  • Both A and R are correct and R is correct explanation of A
  • Both A and R are correct but R is not correct explanation of A
  • A is true, R is false
  • A is false, R is true
Q.50

If f(t) is an odd function, F(jω) =

0 h : 0 m : 1 s