GATE EC LTI Systems questions

For the discrete-time system shown in the figure, the poles of the system transfer function are located at

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 is $h[n]$. If $h[0]=1$, we can conclude

The open-loop transfer function of a plant in a unity feedback configuration is given as $G(s) = \frac{K(s+4)}{(s+8)(s^2-9)}$. The value of the gain $K(>0)$ for which $-1+j2$ lies on the root locus is _________.

A plant transfer function is given as $G(s)= \bigg( K_p+ \frac{K_1}{s} \bigg) \frac{1}{s(s+2)}$. When the plant operates in a unity feedback configuration, the condition for the stability of the closed loop system is

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 is desired that the output signal $z(t)=10x(t)$, the maximum value of $W$ (in Hz) should be strictly less than _____________.

Input $x(t)$ and output $y(t)$ of an LTI system are related by the differential equation $y’’(t) – y’(t) – 6y(t) = x(t).$ If the system is neither causal nor stable, the impulse response $h(t)$ of the system is

The transfer function of a mass-spring-damper system is given by $$G(S) = \dfrac{1}{Ms^{2}+Bs+K}$$ The frequency response data for the system are given in the following table. …

The impulse response of an LTI system can be obtained by

The phase margin (in degrees) of the system $G(s) = \dfrac{10}{s(s+10)}$ is _______.

The transfer function of a first-order controller is given as $$G_{C}(s) = \dfrac{K(s+a)}{s+b}$$where $K,a$ and ܾ$b$ are positive real numbers. The condition for this controller to act as a phase lead compensator is

The characteristic equation of an LTI system is given by $F(s) = s^{5} + 2s^{4} + 3s^{3} + 6s^{2} – 4s – 8 = 0.$ The number of roots that lie strictly in the left half $s$-plane is _________.

A discrete-time signal $x[n] = \sin(\pi^{2}n),n$ being an integer, is

A continuous, linear time-invariant filter has an impulse response $h(t)$ described by $$h(t) = \begin{cases}3 & \text{for } 0 \leq t \leq 3 \\ 0 & \text{otherwise} \end{cases}$$ When a constant input of value $5$ is applied to this filter, the steady state output is ________.

The forward path transfer function of a unity negative feedback system is given by $$G(s) = \frac{K}{(s+2)(s-1)}$$. The value of $K$ which will place both the poles of the closed-loop system at the same location, is _______.

For the following system, when $X_{1} (s) = 0$, the transfer function $\frac{Y(s)}{X_{2}(s)}$ is

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 itself, the value of $y[4]$ is _______ .

An unforced linear time invariant (LTI) system is represented by $$\begin{bmatrix} x_1 \\ x_2 \end{bmatrix} = \begin{bmatrix} -1 & 0 \\ 0& -2 \end{bmatrix} \begin{bmatrix} x_1 \\ x_2 \end{bmatrix}$$ If the initial conditions are $x_1(0)= 1$ and $x_2(0)= -1$, the solution of the state equation is

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

Consider the following block diagram in the figure. The transfer function $\frac{C(s)}{R(s)}$ is

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 $p=\frac{1}{2},q=-\frac{1}{4},\mid r \mid < 1.$ If the zero of $H(z)$ lies on the unit circle, then $r$ $=$ _________