Recent questions tagged continuous-time-signals

1 1 vote
1 1 answer
439
439 views
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]$\dfrac{e^{-2 s}}{s^{2}(s-...
0 0 votes
0 0 answers
214
214 views
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, \text { and } x_{2...
0 0 votes
0 0 answers
172
172 views
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_{-\infty}^{\inf...
1 1 vote
0 0 answers
146
146 views
Consider a real signal $x(t),-\infty < t < \infty$, such that$x(t) = 0\quad\text{for}\quad t <0, x(t) =2 \quad\text{for} \quad0 \leq t < 1\quad \text{and}\quad x(t) = 0\q...
0 0 votes
0 0 answers
141
141 views
Consider a real baseband signal $x(t)=e^{-2 t}$, for $t$ (in seconds) $\geq 0$.If $99 \%$ of energy of $x(t)$ lies within $B \mathrm{~Hz}$, then which of the following op...
0 0 votes
0 0 answers
194
194 views
Consider a real, narrowband signal $x(t)=A(t) \cos \left[2 \pi f_{c} t+\theta(t)\right]$ where the maximum frequency components of $A(t)$ and $\theta(t)$ are $f_{M}$ and ...
0 0 votes
0 0 answers
117
117 views
Let $x_{1}(t)=\cos (2 \pi n t)$ and $x_{2}(t)=2 \sin (4 \pi n t)$ represent two sinusoids for a positive integer $n$ and $-\infty < t < \infty$.Which of the following sta...
3 3 votes
1 1 answer
1.0k
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Consider a continuous-time, real-valued signal $f(t)$ whose Fourier transform $F(\omega)=\int_{-\infty}^{\infty} f(t) \exp (-j \: \omega t) d t$ exists.Which one of the f...
0 0 votes
0 0 answers
765
765 views
Consider a continuous-time finite-energy signal $f(t)$ whose Fourier transform vanishes outside the frequency interval $\left[-\omega_{c}, \omega_{c}\right]$, where $\ome...
0 0 votes
0 0 answers
386
386 views
Let $f(t)$ be a periodic signal with fundamental period $T_{0}>0$. Consider the signal $y(t)=f(\alpha t)$, where $\alpha>1$.The Fourier series expansions of $f(t)$ and $y...
1 1 vote
1 1 answer
568
568 views
The diode in the circuit shown below is ideal. The input voltage (in Volts) is given by $V_{I}=10 \sin 100 \pi t$, where time $t$ is in seconds.The time duration (in $\ma...
2 2 votes
1 1 answer
1.9k
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​​​​A causal and stable $\text{LTI}$ system with impulse response $h(t)$ produces an output $y(t)$ for an input signal $x(t)$. A signal $x(0.5 t)$ is applied to another c...
2 2 votes
1 1 answer
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2.5k views
Consider two continuous time signals $x(t)$ and $y(t)$ as shown below If $X(f)$ denotes the Fourier transform of $x(t)$, then the Fourier transform of $y(t)$ is $\_\_\_\_...
2 2 votes
1 1 answer
914
914 views
​​​​A continuous time signal $x(t)=2 \cos (8 \pi t+\pi / 3)$ is sampled at a rate of $15 \mathrm{~Hz}$. The sampled signal $x_{s}(t)$ when passed through an LTI system wi...
0 0 votes
1 1 answer
857
857 views
Consider a system with input $x(t)$ and output $y(t)=x\left(e^{t}\right)$. The system isCausal and time invariant.Non-causal and time varying.Causal and time varying.Non-...
0 0 votes
0 0 answers
853
853 views
Let $m(t)$ be a strictly band-limited signal with bandwidth $B$ and energy $E$. Assuming $\omega_{0}=10 B$, the energy in the $m(t) \cos \omega_{0} t$ is$\frac{E}{4}$$\f...
1 1 vote
0 0 answers
636
636 views
The Fourier transform $X(\omega)$ of $x(t)=e^{-t^{2}}$ isNote: $\int_{-\infty}^{\infty} e^{-y^{2}} d y=\sqrt{\pi}$$\sqrt{\pi} e^{\frac{\omega^{2}}{2}}$$\frac{e^{-\frac{\o...
1 1 vote
1 1 answer
871
871 views
In the table shown below, match the signal type with its spectral characteristics. Signal type Spectral characteristics (i) Continuous, aperiodic(a) Continuous, aperiod...
1 1 vote
0 0 answers
834
834 views
Let $x(t)=10 \cos (10.5 W t)$ be passed through an LTI system having impulse response $h(t)=\pi\left(\frac{\sin W t}{\pi t}\right)^{2} \cos 10 Wt$. The output of the sys...
1 1 vote
0 0 answers
479
479 views
Let $\mathrm{x}_1(\mathrm{t})$ and $\mathrm{x}_2(\mathrm{t})$ be two band-limited signals having bandwidth $B=4 \pi \times 10^3 \; \mathrm{rad} / \mathrm{s}$ each. In the...
1 1 vote
0 0 answers
557
557 views
Let $\mathrm{x}_1(\mathrm{t})=\mathrm{u}(\mathrm{t}+1.5)-\mathrm{u}(\mathrm{t}-1.5)$ and $\mathrm{x}_2(\mathrm{t})$ is shown in the figure below. For $\mathrm{y}(\mathrm{...
0 0 votes
0 0 answers
530
530 views
Let $X(t)$ be a white Gaussian noise with power spectral density $\frac{1}{2} \mathrm{~W} / \mathrm{Hz}$. If $X(t)$ is input to an LTI system with impulse response $e^{-t...
2 2 votes
0 0 answers
403
403 views
Let $h(t)$ be the impulse response of an ideal low-pass filter with cut-off frequency $5 \mathrm{kHz} .\; \mathrm{Let}\; g[n]= h(n T)$, for integer $n$, be a sampled vers...
2 2 votes
0 0 answers
373
373 views
Consider the following input $x(t)$ and output $y(t)$ pairs for two different systems.$x(t)=\sin (t), y(t)=\cos (t),$$x(t)=t+\sin (t), y(t)=2 t+\sin (t-1).$Which of these...
2 2 votes
0 0 answers
292
292 views
It is known that the signal $x(t)$, where $t$ denotes time, belongs to the following class:\[\left\{A \sin \left(2 \pi f_{0} t+\theta\right): f_{0}=1 \mathrm{~Hz}, 0 \leq...
1 1 vote
0 0 answers
292
292 views
The two-dimensional Fourier transform of a function $f(t, s)$ is given by\[F(\omega, \theta)=\int_{-\infty}^{\infty} \int_{-\infty}^{\infty} f(t, s) \exp (-j \omega t) \e...
1 1 vote
0 0 answers
294
294 views
Consider a periodic square wave $f(t)$ with a period of $1$ second such that $f(t)=1$ for $t \in[0,1 / 2)$ and $f(t)=-1$ for $t \in[1 / 2,1)$. It is passed through an ide...
1 1 vote
0 0 answers
319
319 views
Let $u(t)$ be the unit step function that takes value $1$ for $t \geq 0$ and is zero otherwise. Let $f(t)=e^{-t} u(t)$ and $g(t)=u(t) u(1-t)$. Then the convolution of $f(...
1 1 vote
0 0 answers
353
353 views
A linear time-invariant system has a transfer function $H(s)=1 /(1+s)$. If the input to the system is $\cos (t)$, the output is$\left(e^{j t}+e^{-j t}\right) / 2$ where $...
1 1 vote
0 0 answers
293
293 views
$x(t)$ is a signal of bandwidth $4 \mathrm{~kHz}$. It was sampled at a rate of $16 \mathrm{~kHz}$.\[x_{n}=x(n T), \quad n \text { integer, } \quad T=\frac{1}{16} \mathrm{...