1
GATE ECE 2026
MCQ (Single Correct Answer)
+1
-0.33

The Laplace Transform of the signal $x(t)=u(t-2) *(t u(t))$ is given by which of the following expressions?

["*" represents convolution operator]

A

$\frac{e^{-2 s}}{s^2(s-2)}$

B

$\frac{e^{-2(s-2)}}{s^3}$

C

$\frac{s e^{-2 s}}{(s-2)^2}$

D

$\frac{e^{-2 s}}{s^3}$

2
GATE ECE 2026
MCQ (Single Correct Answer)
+1
-0.33

Two analog signals $x_1(t)$ and $x_2(t)$ ( $t$ in second), are sampled at a rate $F_s=40 \mathrm{~Hz}$, where $x_1(t)=\cos (20 \pi t), t \geq 0$, and $x_2(t)=\cos (100 \pi t), t \geq 0$.

The first ten samples (starting from $t=0$ ) are considered for the analysis.

Which of the following statements is TRUE?

A

All of the first three samples of $x_1(t)$ are greater than the corresponding samples of $x_2(t)$.

B

All of the last three samples of $x_1(t)$ are greater than the corresponding samples of $x_2(t)$.

C

All of the samples of $x_2(t)$ are greater than the corresponding samples of $x_1(t)$.

D

All of the fourth to seventh samples of $x_1(t)$ are equal to the corresponding samples of $x_2(t)$.

3
GATE ECE 2026
MCQ (Single Correct Answer)
+1
-0.33

The response of a discrete time system $\mathrm{y}[\mathrm{n}]$ obeys the following relation:

$$ y[n]=\frac{5}{6} y[n-1]-\frac{1}{6} y[n-2]+x[n] . $$

The input to the system is $x[n]=\delta[n]-\frac{1}{3} \delta[n-1]$.

Which of the following options is TRUE for $y[n]$ ?

A

Stable and causal response

B

Stable and non-causal response

C

Unstable and causal response

D

Unstable and non-causal response

4
GATE ECE 2026
MCQ (Single Correct Answer)
+2
-0.67

The continuous time signal $x(t)$ is real, periodic with period $T$ and satisfies the Dirichlet conditions.

The Fourier series representation of $x(t)=\sum_{n=-\infty}^{\infty} a_n e^{j\left(\frac{2 \pi n t}{T}\right)}$ and $x(t)$ satisfies the following:

$$ x\left(t-\frac{T}{2}\right)=-x(t) $$

For any integer $m$, which of the following options is correct?

A

$a_{2 m}=0$

B

$a_{2 m}=1$

C

$a_{2 m}=a_{2 m+1}$

D

$a_{2 m}=-1$