Questions without an upvoted answer in Signals and Systems

A square wave signal of frequency $20$ $\mathrm{kHz}$ is passed through an ideal low-pass filter with cut-off frequency of $21$ $\mathrm{kHz}$. The output signal is a $\_...

Given $x(t)=4 \sin (15 \pi t)+7 \cos (4 \pi t)$, where $t$ is in seconds.The fundamental period of $x(t)$ is $\_\_\_\_\_\_$ seconds.$15$$60$$30$$2$

A signal $x(t)$ is shown below.The plot of $y(t)=1-x(4-t)$ is shown in $\_\_\_\_\_\_$.  

In the table shown below, List-I are the system responses to input $x(t)$ and List-II are the system properties. The correct matching is $\_\_\_\_\_\_$.$$\begin{array}{|l...

Given two signals: $x(t)=u(t-2)-u(t-3)$, and $y(t)=e^{-4 t} u(t)$. If $z(t)=x(t) * y(t)$, then $Z(s)$ is $\_\_\_\_$.$\dfrac{e^{-3 s}\left[e^{s}-1\right]}{s(s+4)}$$\dfrac{...

Let $f(t)=\left\{\begin{array}{cc}1, & t \in[0,2] \\ -t+3, & t \in[2,3] \\ 0, & \text { otherwise }\end{array}\right.$Then$\int_{-\infty}^{\infty} f(\tau) d \tau=$ $\_\_\...

Let a continuous-time signal be $x(t)=e^{j 9 t}+e^{j 5 t}$, where $j=\sqrt{-1}$ and $t$ is in seconds. The fundamental period of magnitude of $x(t)$, in seconds, is$\pi$$...

Let $y[n]=\frac{1}{\alpha} y[n-1]+x[n]$, where $\alpha>1$ and real, represent a difference equation of a causal discrete-time linear time invariant system. The system is ...

Let $f(t)$ and $g(t)$ represent continuous-time real-valued signals. If $h(t)$ denotes cross-correlation between $f(t)$ and $g(-t)$, its continuous-time Fourier transform...

Choose the eigenfunction(s) of stable linear time-invariant continuous-time systems from the following options.$e^{j \frac{2 \pi}{3} t}$$\cos \left(\frac{2 \pi}{3} t\righ...

Let $X\left(e^{j \omega}\right)$ represent the discrete time Fourier transform of a $4$-length sequence $x[n]$, where $x[0]=1, x =2, x =2$, and $x[3]=4 . X\left(e^{j \ome...

A signal $V_{M}=5 \sin (\pi t / 3) \mathrm{V}$ is applied to the circuit consisting of a switch $S$ and capacitor $C=0.1 \mu \mathrm{~F}$, as shown in the figure. The out...

A discrete-time sequence is given by $x[n]=[1,2,3,4]$ for $0 \leq n \leq 3$. The zero lag auto-correlation value of $x[n]$ is$1$$10$$20$$30$

Consider a filter defined by the difference equation$$ y[n]-0.5 y[n-2]=a x[n-4] $$where $x[n]$ and $y[n]$ represent the input and output, respectively. If the magnitude r...

The number of complex multiplications required for computing a $16$-point DFT using the decimation-in-time radix-$2$ FFT is $\_\_\_\_\_\_\_$ (in integer).

The Nyquist sampling frequency for $x(t)=10 \sin ^{2}(200 \pi t)$ is $\_\_\_\_\_\_\_ \mathrm{~Hz}$ (rounded off to nearest integer).

The current $i(t)$ drawn by a circuit is given as$$i(t)=4+30 \cos (t)-20 \sin (t)+15 \cos (3 t)-10 \sin (3 t) \mathrm{A}$$The root-mean-square value of $i(t)$ is $\_\_\_\...

​​​​Consider a discrete-time sequence$x[n]=\begin{cases} (0.2)^{n}, & 0 \leq n \leq 7 \\ 0, & \text { otherwise } \end{cases}$The region of convergence of $X(z)$, the $z$...

​​​​​Laplace transform of a signal $x(t)$ is$$X(s)=\frac{1}{s^{2}+13 s+42}$$Let $u(t)$ be the unit step function. Choose the signal $x(t)$ from the following options if t...

Consider the discrete-time signal $x[n]=u[-n+5]-u[n+3],$ where $u[n]=\left\{\begin{array}{l}1 ; n \geq 0 \\ 0 ; n<0\end{array}\right . $ The smallest $n$ for which $x[n]=...

Let $y(t)=x(4 t),$ where $x(t)$ is a continuous-time periodic signal with fundamental period of $100 \mathrm{~s}.$ The fundamental period of $ y(t)$ is___________$s$ (rou...

The impulse response of an LTI system is $h(t)=\delta(t)+0.5 \delta(t-4)$, where $\delta(t)$ is the continuous-time unit impulse signal. If the input signal $x(t)=\cos \l...

The Laplace transform of the continuous-time signal $x(t)=e^{-3 t} u(t-5)$ is_____________, where $u(t)$ denotes the continuous-time unit step signal.$\frac{e^{-5 s}}{s+3...

A continuous real-valued signal $x(t)$ has finite positive energy and $x(t)=0, \forall \; t<0.$ From the list given below, select ALL the signals whose continuous-time Fo...

The $\mathrm{R}-\mathrm{L}$ circuit with $\mathrm{R}=10 ~ \mathrm{k} \Omega$ and $\mathrm{L}=1 \mathrm{mH}$ is excited by a step current $\mathrm{I}_{\mathrm{u}} \mathrm{...

The input $x(t)$ to a system is related to its output $y(t)$ as$$\frac{dy(t)}{dt} + y(t) = 3x (t-3)u (t-3)$$Here $u(t)$ represents a unit-step function.The transfer funct...

A periodic function $f(x),$ with period $2,$ is defined as$f(x) = \left\{\begin{matrix} -1 -x & -1 \leq x < 0 \\ 1 – x & 0 < x \leq 1 \end{matrix}\right. $The Fourier ser...

The output of a system $y(t)$ is related to its input $x(t)$ according to the relation $y(t) = x(t) \sin (2 \pi t).$ This system is __________Linear and time-variantNon-l...

A signal $x(t)$ is band-limited between $100 \; \text{Hz}$ and $200 \; \text{Hz}.$A signal $y(t)$ is related to $x(t)$ as follows:$$y(t) = x (2t – 5)$$The statement that ...

Consider the transfer function$$H_{c}(S) = \frac{1}{(s+1)(s+3)}$$Bilinear transformation with a sampling period of $0.1 \; \text{s}$ is employed to obtain the discrete-ti...

The signal $x(t) = (t-1)^{2}u(t-1),$ where $u(t)$ is the unit-step function, has the Laplace transform $X(s).$ The value of $X(1)$ is ________$\frac{1}{e}$$\frac{2}{e}$$2...

The input-output relationship of an $\text{LTI}$ system is given below.For an input $x\left [ n \right ]$ shown belowthe peak value of the output when $x\left [ n \right ...

The signal $\sin\left ( \sqrt{2\pi t} \right )$ isperiodic with period $T=\sqrt{2\pi }$not periodic periodic with period $T=2\pi$periodic with period $T=4\pi ^{2}$

The step response of a circuit is seen to have an oscillatory behavior at the output with oscillations dying down after some time. The correct inference$\text{(s)}$ regar...

Given $y\left ( t \right )=e^{-3t}u\left ( t \right )\ast u\left ( t+3 \right )$, where $\ast$ denotes convolution operation. The value of $y\left ( t \right )$ as $t\rig...

A sinusoid of $\text{10 kHz}$ is sampled at $\text{15 k samples/s}.$ The resulting signal is passed through an ideal low pass filter $(LPF)$ with cut-off frequency of $\t...

Let $g[n]=\left\{ \begin{array}{rcl} 1 & n=0 \\0 &n=\pm 1,\pm 2,\pm 3,\dots \end{array}\right. $ and $h[n]=\left\{ \begin{array}{rcl} 1 & n=0,3,6,9\dots \\0 & otherwise \...

Consider the finite sequence $X=(1,1,1).$ The Inverse Discrete Fourier Transform (IDFT) of X is given as $\text{(x(0), x(1), x(2)).}$ The value of $x(2)$ is _______

A differentiator has a transfer function whosephase increases linearly with frequencymagnitude remains constantmagnitude increases linearly with frequencymagnitude decrea...

Consider the signal $x[n]=\sin(2\pi n)u[n]$, where $u[n]= \left\{ \begin{array}{rcl} 1 & n=0,1,2,3\dots \\ 0 & otherwise\end{array}\right. $The period of this signal $x[n...