Q.1

Which one of following is a stataic system?

  • y(n) = x(n) - x(n - 1)
  • y(n) = x(2n) - x(2n-1)
  • y(n) = x(n - 1)
  • y(n) = ex(n)
Q.2

If a complex voltage wave is applied to a pure inductance, the resulting current wave is much smoother than the voltage wave.

  • True
  • False
Q.3

Which one of the following is the correct statement? The region of convergence of z transform of x[n] consists of the values of z for which x[n] r-n is

  • absolutely integrable
  • absolutely summable
  • unity
  • < 1
Q.4

Fourier transform o the function f(t) = 1 is

  • 2p δ (ω)
  • p δ (ω)
  • δ(ω)/2p
  • δ(ω)/p
Q.5

If v(t) = 0 for t < 0 and e-at for t ≥ 0 V(jω) = 1/(a + jω).

  • True
  • False
Q.6

The term 'energy spectral density' is associated with

  • periodic waveform
  • non-periodic waveform
  • both perodic and non -perodic waveform
  • none of the above
Q.7

unit step is a

  • energy signal
  • power signal
  • neither energy nor power signal
  • none
Q.8

For formation of state equations, resistance of the circuit

  • should be in tree
  • should be in cotree
  • may be in tree or cotree
  • none of the above
Q.9

In a Communication system, noise is most likely to affect the signal.

  • at the transmitter
  • In the channel
  • in Information source
  • at the destination
Q.10

If R(t) is autocorrelation of a waveform v(t) and R(is autocorrelation for t =then

  • R(0) > R(t)
  • R(0) ≥ R(t)
  • R(0) < R(t)
  • R(0) ≤ R(t)
Q.11

Which of the following is/are not a property/properties power spectral density function Sx(ω)?

  • Sx(ω) is real function of ω
  • Sx(ω) is a even function of ω
  • Sx(ω) is non-positive function of ωSx(ω) ≤ 0 for all ω
  • All of the above
Q.12

The discrete time system describes by y(n) = x(n2) is

  • casual, Linear, time varying
  • casual, non-linear, timevari
  • non-casual, Linear, time invariant
  • non-casual, non-linear, time variant
Q.13

A system is said to be static system, when present output depend upon

  • present I/P
  • presrent and past
  • present and future
  • past and future
Q.14

The function f(t) = E[u(t - a) - u(t - b)] is

  • a pulse function originating at t = a
  • a step function orginating at t = 0
  • an exponential function originating at t = a
  • a pulse function originating at t = a and duration (b - a)
Q.15

If f(t) =F(jω) = 2p δ(ω).

  • True
  • False
Q.16

A function will have only sine terms if

  • f(t) = - f(t)
  • f(-t) = f(t)
  • f(-t) = -f(t)
  • none of the above
Q.17

Assertion (A): The function δ'(t - b) is equal to 0 for t ≠ b

Reason (R): A number of impulses spaced from one another form an impulse train.

  • 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.18

Assertion (A): Impulse function is an important function in network analysis.

Reason (R): Convolution integral enables us to find the response of a network to an arbitary input in terms of the impulse response.

  • 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

If average correlation between v1(t) and v2(t) is R12(t) and average correlation between v2(t) and v1(t) is R21(t) then

  • R12(t) = R21(t)
  • R21(t) = R12(t)
  • R12(t) = - R21(t)
  • none of these
Q.20

A casual LTI system is described by the difference equation
2y[n] = ay[n -- 2x[n] + βx[n -
The system is stable only if

  • |a| = 2 |β| < 2
  • |a| > 2 |β| > 2
  • |a| < 2 any value of β
  • |β| < 2, any value of a
Q.21

A system is stable if ROC

  • include the unit circle
  • exclude the unit circle
  • lies on Circle
  • entire plane
Q.22

If ROC of x[n] is R1 then ROC of an x[n] is

  • R1a
  • R1/a
  • a/R1
  • R1 + a
Q.23

If two mutually exclusive events A and B can happen in m and n ways, then either A or B can happen in (m + n) ways.

  • True
  • False
Q.24

unit step is a

  • energy signal
  • power signal
  • neither energy nor power signal
  • none
Q.25

If a function f(t) is an odd, function, its Fourier series

  • contains only sine terms
  • contains only cosine terms
  • contains a constant and sine terms
  • contains a constant and cosine
Q.26

ROC of sequence x[n] = δ[n] is

  • Not exist
  • z = 0
  • Entire Plane
  • Entire Plane expect z = 0, z = ∞
Q.27

If X(z) = (1 - a)z-1/[(1 - z-1)(1 - az-1)] and 1 < |z|, the final value of xk is

  • 0
  • 1
  • ∞
  • 2
Q.28

The range of values of a and b for which the linear time invariant system with impulse response.
h(n) = an n ≥ 0
        = bn n < 0
will be stable if

  • |a| > 1, |b| > 1
  • |a| < 1, |b| < 1
  • |a| < 1, |b| > 1
  • |a| > 1, |b| < 1
Q.29

If f(- t) = f(t), the function f(t) has only cosine terms.

  • True
  • False
Q.30

The inverse Laplace transform of 1/(s - a)2 is

  • eat
  • t eat
  • t2 eat
  • eat/t
Q.31

A discrete LTI system is non-casual if its impulse response is

  • an ∪(n - 2)
  • an-2 ∪(n)
  • an+2 ∪(n)
  • an ∪(n + 2)
Q.32

A stationary process has

  • all statistical properties independent of time
  • all statistical properties dependent of time
  • zero variance
  • ensemble average equal to time average
Q.33

The Laplace transform of a unit step function is

  • 1
  • 1 / s
  • s
  • 1 / s2
Q.34

x = AX + Bu is a state equation.

  • True
  • False
Q.35

Which of the following can be impulse response of a casual system?

Q.36

If two mutually exclusive events A and B can happen in m and n ways, then either A or B can happen in (m + n) ways.

  • True
  • False
Q.37

For a second order system, damping ratio ζ is such that 0 < ζ <. Then the roots of characteristic equation are

  • real but not equal
  • real and equal
  • complex conjugate
  • imaginary
Q.38

The function δ'(t - b) is a unit doublet.

  • True
  • False
Q.39

The standard deviation of a set of observations is the rms value of the deviation from the arithmetic mean.

  • True
  • False
Q.40

If the sequence |xn|1/n converges, then the series converages absolutely is

  • Ratio test
  • Root test
  • Convergence test
  • Divergence test
Q.41

The output of a linear system for any input can be computed in which of the following ways?

  • Only by summation of inpulse response by convolution integral
  • Only by summation of step response by superposition integral
  • Neither a nor b
  • Either (a) or (b)
Q.42

Which one is correct option about ROC?

  • ROC does not contain any pole
  • ROC of finite duration sequence is entire plane expect z = 0, z = ∞
  • a and b
  • only a
Q.43

If f(t)↔ F(jω), and f(t) is real, then F(- jω)

  • F(jω)
  • F*(j↔)
  • F*(- jω)
  • none of these
Q.44

Final value theorem is used to find

  • steady state value of system output
  • initial value of output
  • transient beaviour of output
  • none of these
Q.45

Which one of following is correct condition to check the stability of sysytem in terms of impulse response?

  • Σ(x(n)) < ∞
  • Σx(n) < 0
  • Σx(n) = 0
  • Σx(n) = ∞
Q.46

If xk = 0 for k < 0 and = 2k for k ≥ 0 X(z) = z/(z -2).

  • True
  • False
Q.47

Assertion (A): If an event A can happen in m ways and another event B can happen in n ways, both can happen in mn ways.

Reason (R): Two events are mutually exclusive if happening of either precludes the occurrence of other.

  • 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.48

The signal m(t) =cospt is sampled at the rate of Fs =Hz, then determine signal after sampling.

  • 4 cos 100 pt + 8 sin 200 pt
  • 4 cos 100 pt + 8 sin 200 pt + cos 75 pt
  • 4 cos 25 pt + 8 sin 50 pt + cos 75 pt
  • none
Q.49

A function will have only sine terms if

  • f(t) = - f(t)
  • f(-t) = f(t)
  • f(-t) = -f(t)
  • none of the above
Q.50

Fourier transform o the function f(t) = 1 is

  • 2p δ (ω)
  • p δ (ω)
  • δ(ω)/2p
  • δ(ω)/p
0 h : 0 m : 1 s