Recent questions in Continuous-time Signals

Consider two real sequences with time-origin marked by the bold value, $$x_{1}[n] = \{\textbf{1},2,3,0\},\:\:x_{2}[n] = \{\textbf{1},3,2,1\}$$ Let ܺ$X_{1}(k)$ and ܺ$X_{2}...

The result of the convolution $x(-t) * \delta (-t-t_0)$ is$x(t+t_0)$$x(t-t_0)$$x(-t+t_0)$$x(-t – t_0)$

The waveform of a periodic signal $x(t)$ is shown in the figure.A signal $g(t)$ is defined by $g(t) = x \big( \frac{t-1}{2} \big)$. The average power of $g(t)$ is _______...

Consider the signal $s(t)=m(t) \cos(2 \pi \: f_ct)+ \hat{m}(t) \sin(2 \pi f_c t)$ where $\hat{m}(t)$ denotes the Hilbert transform of $m(t)$ and the bandwidth of $m(t)$ i...

In the circuit shown, switch SW is closed at $t=0$. Assuming zero initial conditions, the value of $v_c(t)$ (in Volts) at $t=1$ sec is _________.

The pole-zero diagram of a casual and stable discrete-time system is shown in the figure. The zero at the origin has multiplicity $4$. The impulse response of the system ...

In the system shown in Figure (a), $m(t)$ is a low-pass signal with bandwidth $W$ Hz. The frequency response of the band-pass filter $H(f)$ is shown in Figure (b). If it ...

A Fourier transform pair is given by $$\left ( \frac{2}{3} \right ) \: u[n+3] \overset{FT}{\Leftrightarrow} \frac{Ae^{-j6 \pi f}}{1- (\frac{2}{3} ) e^{-j2 \pi f}}$$ where...

A real-valued signal $x(t)$ limited to the frequency band $\mid f \mid \leq \frac{W}{2}$ is passed through a linear time invariant system whose frequency response is $$H(...

The sequence $x[n] = 0.5^n \: u[n]$, where $u[n]$ is the unit step sequence, is convolved with itself to obtain $y[n]$. Then $\Sigma_{n= -\infty}^{+ \infty} y[n]$ is ____...

A stable linear time variant (LTI) system has a transfer function $H(s) = \frac{1}{s^2+s-6}$. To make this system casual it needs to be cascaded with another LTI system ...

A casual LTI system has zero initial conditions and impulse response $h(t)$. Its input $x(t)$ and output $y(t)$ are related through the linear constant-coefficient differ...

The $N$-point DFT $X$ of a sequence $x[n]$, $0 \leq n \leq N-1$ is given by $$X[k] = \frac{1}{\sqrt{N}} \Sigma_{n=0}^{N-1} x[n] e^{-j \frac{2\pi}{N}nk}, \: \: \: 0 \leq k...

Let $H_{1}(z)= (1-pz^{-1})^{-1},H_{2}(z)= (1-qz^{-1})^{-1},H(z)=H_{1}(z)+rH_{2}(z).$ The quantities $p,$ $q$, $r$ are real numbers. Consider $p=\frac{1}{2},q=-\frac{1}{4}...

The $z$-transform of the sequence $x[n]$ is given by $X(z)=\frac{1}{(1-2z^{-1})^{2}},$ with the region of convergence $\mid z \mid >2$. Then, $x $ is _________.

In the root locus plot shown in the figure, the pole/zero marks and the arrows have been removed. Which one of the following transfer functions has this root locus? ...

Let $x[n] = x[-n]$. Let $X(z)$ be the $z$-transform of $x[n]$. If $0.5 + j 0.25$ is a zero of $X(z)$, which one of the following must also be a zero of $x(z)$$0.5 – j 0.2...

Consider a discrete-time signal $$ x[n]= \begin{cases} n & \text{for } 0\leq n\leq 10 \\ 0 & \text{otherwise }\end{cases}$$ If $y[n]$ is the convolution of $x[n]$ with it...

An unforced linear time invariant (LTI) system is represented by $$\begin{bmatrix} x_1 \\ x_2 \end{bmatrix} = \begin{bmatrix} -1 & 0 \\ 0& -2 \end{bmatrix} \begin{bmatrix...

Consider the state space system expressed by the signal flow diagram shown in the figure. The corresponding system isalways controllablealw...