Electronics and Communication GATE 2023 Questions with Answer

Ques 53 Network Theory


The switch S1 was closed and S2 was open for a long time. At t=0, switch S1 is opened and S2 is closed, simultaneously. The value of ic(0+), in amperes, is

A

1

B

-1

C

0.2

D

0.8


Ques 54 Signal and Systems


Consider a system with input x(t) and output y(t) = x(et). The system is

A

Causal and time invariant.

B

Non-causal and time varying.

C

Causal and time varying.

D

Non-causal and time invariant.


Ques 55 Signal and Systems


Let m(t) be a strictly band-limited signal with bandwidth B and energy E. Assuming ωo = 10B, the energy in the signal m(t)cos ωot is

A

E/4

B

E/2

C

E

D

2E


Ques 56 Signal and Systems


The Fourier transform X(ω) of x(t) = e-t2 is Note: ∫-∞e-y2dy = √π

A

√πeω2/2

B

e2/4/2√π

C

√πe2/4

D

√πe2/2


Ques 57 Signal and Systems


In the table shown below, match the signal type with its spectral characteristics.

A

(i) → (a), (ii) → (b), (iii) → (c), (iv) → (d)

B

(i) → (a), (ii) → (c), (iii) → (b), (iv) → (d)

C

(i) → (d), (ii) → (b), (iii) → (c), (iv) → (a)

D

(i) → (a), (ii) → (c), (iii) → (d), (iv) → (b)


Ques 58 Signal and Systems


For a real signal, which of the following is/are valid power spectral density/densities?

A

Sx(ω) = 2/9 + ω2

B

SX(ω) = e2cos2ω

C

D


Ques 59 Signal and Systems


Consider a discrete-time periodic signal with period N = 5. Let the discrete-time Fourier series (DTFS) representation be x[n] = Σ4k=0akepk2πn/5, where a0 = 1, a1 = 3j, a2 = 2j, a3 = -2j and a4 = -3j. The value of the sum Σ4n=0x[n]sin4πn/5

A

-10

B

10

C

-2

D

2


Ques 60 Signal and Systems


Let an input x[n] having discrete time Fourier transform
X(ejΩ) = 1 - e-jΩ + 2e-3jΩ be passed through an LTI system. The frequency response of the LTI system is H(e) = 1 - 1/2 e-j2Ω. The output y[n] of the system is

A

δ[n] + δ[n - 1] - 1/2 δ[n - 2] - 5/2 δ[n - 3] + δ[n - 5]

B

δ[n] - δ[n - 1] - 1/2 δ[n - 2] - 5/2 δ[n - 3] + δ[n - 5]

C

δ[n] - δ[n - 1] - 1/2 δ[n - 2] + 5/2 δ[n - 3] - δ[n - 5]

D

δ[n] + δ[n - 1] + 1/2 δ[n - 2] + 5/2 δ[n - 3] + δ[n - 5]


Ques 61 Signal and Systems


Let x(t) = 10 cos(10.5Wt) be passed through an LTI system having impulse response h(t) = π(sin Wt/πt)2cos 10Wt. The output of the system is

A

(15W/4)cos(10.5Wt)

B

(15W/2)cos(10.5Wt)

C

(15W/8)cos(10.5Wt)

D

(15W)cos(10.5Wt)


Ques 62 Signal and Systems


Let x1(t) and x2(t) be two band-limited signals having bandwidth B = 4π × 103 rad/s each. In the figure below, the Nyquist sampling frequency, in rad/s, required to sample y(t), is

A

20π × 103

B

40π × 103

C

8π × 103

D

32π × 103


Ques 63 Signal and Systems


Let x1(t) = u(t + 1.5) - u(t - 1.5) and x2(t) is shown in the figure below. For y(t) = x1(t) * x2(t), the ∫-∞y(t)dt is ____ (rounded off to the nearest integer).

6 is the correct answer.


Ques 64 Signal and Systems


Let X(t) be a white Gaussian noise with power spectral density 1/2 W/Hz. If X(t) is input to an LTI system with impulse response e-tu(t), the average power of the system output is ____ W (rounded off to two decimal places).

0.25 is the correct answer.


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