Recent questions tagged continuous-time-signals

A bandlimited signal $x(t)$ with $a^{\prime}$ spectrum $X(f)$ as shown in first figure is processed as shown in second figure is $p(t)$ is a periodic train of impulses as...

A signal $x(t)$ has a Fourier transform $X(\omega)$. If $x(t)$ is a real and odd function of $t$, then $X(\omega)$ isa real and even function of $\omega$a imaginary and o...

A modulated signal is given by\[s(t)=e^{-a t} \cos \left[\left(\omega_{c}+\Delta \omega\right) t\right] u(t),\]where $a, \omega_{c}$ and $\Delta \omega$ are positive cons...

The Fourier series representation of an impules train denoted by\[s(t)=\sum_{n=-\infty}^{n} d\left(t-n \mathrm{~T}_{0}\right) \text { is given by }\]$\frac{1}{\mathrm{~T}...

The Nyquist sampling frequency (in $\mathrm{Hz}$ ) of a signal given by$6 \times 10^{4} \sin c^{2}(400 t)^{*} 10^{6} \sin c^{3}(100 t)$ is$200$$300$$500$$1000$

The power spectral density $\text{(PSD)}$ of a noise process is given by$\mathrm{S}_{\mathrm{N}}(f)=\left\{\begin{array}{cc}10^{-8}\left(1+\frac{|f|-10^8}{10^8}\right) & ...

The transfer function of a system is given by $H(s)=\frac{1}{s^{2}(s-2)}$. The impulse response of the system is$\left(t^{2 *} e^{-2 t}\right) \mathrm{U}(t)$ (* denotes c...

Let $\delta(t)$ denote the delta function. The value of the integral $\int_{-\infty}^{\infty} \delta(t) \cos \left(\frac{3 t}{2}\right) d t$ is$1$$-1$$0$$\frac{\pi}{2}$

If a signal $f(t)$ has energy $E$, the energy of the signal $f(2 t)$ is equal to$\text{E}$$\frac{\mathrm{E}}{2}$$2 \mathrm{E}$$4 \mathrm{E}$

The impulse response functions of four linear systems $\mathrm{S}_{1}, \mathrm{~S}_{2}, \mathrm{~S}_{3}, \mathrm{~S}_{4}$ are given respectively by$\begin{array}{ll} h_{1...

The Nyquist sampling interval, for the signal $\text{Sin c } (700 t)+\text{Sin c } (500 t)$ is$\frac{1}{350} \mathrm{sec}$$\frac{\pi}{350} \sec$$\frac{1}{700} \mathrm{sec...

The Fourier transform $G(\omega)$ of the signal $g(t)$ in the figure, given as $G(w)=\frac{1}{\omega^{2}}\left(\mathrm{e}^{j \omega}-j w e^{j \omega}-1\right)$. Using thi...

A periodic signal $\text{g}(t)$ is shown inthe figure. Determine the PSD of $\text{g}(t)$.

Convolution of $x(t+5)$ with impulse function $\delta(t-7)$ is equal to$x(t-12)$$x(t+12)$$x(t-2)$$x(t+2)$

Which of the following cannot be the Fourier series expansion of a periodic signal ?$x(t)=2 \cos t+3 \cos 3 t$$x(t)=2 \cos \pi t+7 \cos t$$x(t)=\cos t+0.5$$x(t)=2 \cos 1....

The Fourier transform $\mathrm{F}\left\{e^{-t} u(t)\right\}$ is equal to $\frac{1}{1+j 2 \pi f}$. Therefore, $\mathrm{F}\left\{\frac{1}{1+j 2 \pi t}\right\}$ is$e^f u(f)$...

Consider a sampled signal $y(t)=5 \times 10^{\circ}$ ${ }^6 x(t) \sum_{(n-\infty}^{+\infty} \delta \left(t-n \mathrm{T}_x\right)$ where $x(t)=10 \cos \left(8 \pi \times 1...

The Laplace transform of a continuous-time signal $x(t)$ is $X(s)=\frac{5-s}{s^{2}-s-2}$. If the Fourier transform of this signal exists, then $x(t)$ is$e^{2 t} u(t)-2 e^...

In the figure $m(t)=\frac{2 \sin 2 \pi t}{t}, s(t)=\cos 200 \pi t$ and $n(t)$ $=\frac{\sin 199 \pi t}{t}$. The output $y(t)$ will be$\frac{\sin 2 \pi t}{t}$$\frac{\sin 2 ...

A signal $x(t)=100 \cos \left(24 \pi \times 10^{3}\right) t$ is ideally sampled with a sampling period of $50 \; \mu \mathrm{sec}$ and then passed through an ideal lowpas...

A deterministic signal $x(t)=\cos 2 \pi t$ is passed through a differentiator as shown in the figure isDetermine the autocorrelation $R_\mathrm{xx}(T)$ and the power spec...

The trigonometric Fourier series of a periodic time function can have onlycosine termssine termscosine and sine terms$d.c$. and cosine terms

A periodic signal $x(t)$ of period $T_0$ is given by$$ x(t)= \begin{cases}1, & |t|<T_1 \\ 0, & T_1<|t|<\frac{T_0}{2}\end{cases} $$The $\text{d.c}$. component of $x(t)$ is...

The unit impulse response of a linear time-invariant system is the unit step function $u(t)$. For $t>0$, the response of the system to an excitation $e^{-a t} u(t), a>0$ ...

The amplitude spectrum of a Gaussian pulse isuniforma sine functionGaussianan impulse function

The $\text{ACF}$ of a rectangular pulse of duration $\mathrm{T}$ isa rectangular pulse of duration $\mathrm{T}$a rectangular pulse of duration $\mathrm{2T}$a triangular p...

The Fourier transform of a function $x(t)$ is $\mathrm{X}(f)$. The Fourier transform of $\frac{d \mathrm{X}(f)}{d f}$ will be$\frac{dX(f)}{d f}$$j 2 \pi f X(f)$$jf X(f)$$...

Flat top sampling of low pass signalsgives rise to aperture effectimplies oversamplingleads to aliasingintroduces delay distortion

The Fourier transform of a voltage signal $x(t)$ is $X(f)$. The unit of $|X(f)|$ isvoltvolt-secvolt/secvolt $^{2}$