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Control Systems

GATE Electronics & Communication · Control Systems - Block Diagram Reduction · 1990-2026

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2026 Q19

A control system is shown in the Figure. Which option represents the correct transfer function of the system?

mediumanswer key
2026 Q40

For the control system shown in the Figure, the transfer function of a plant, $G(s) = \frac{1}{(s+1)(s+2)}$ is connected in cascade with a compensator $C(s) = K (s + \alpha)$, wher...

hardanswer key
2026 Q41

The state and output equations for a control system are: $\dot{x} = \begin{bmatrix} -4 & -1.5 \\ 4 & 0 \end{bmatrix}x + \begin{bmatrix} 2 \\ 0 \end{bmatrix}u$ $y = \begin{bmatrix}...

mediumanswer key
2026 Q59

Consider the unity negative feedback control system shown in the Figure. The value of gain K (>0) at which the given system will remain marginally stable is __. (Answer in integer)

mediumanswer key
2025 Q16

The Nyquist plot of a system is given in the figure below. Let $\omega_P, \omega_Q, \omega_R$, and $\omega_S$ be the positive frequencies at the points P, Q, R, and S, respectively...

mediumanswer key
2025 Q26

Consider the unity-negative-feedback system shown in Figure (i) below, where gain K ≥ 0. The root locus of this system is shown in Figure (ii) below. For what value(s) of K will th...

mediumanswer key
2025 Q36

Let $G(s) = \frac{1}{10s^2}$ be the transfer function of a second-order system. A controller $M(s)$ is connected to the system $G(s)$ in the configuration shown below. Consider the...

hardanswer key
2025 Q37

Consider the polynomial p(s) = s^5 + 7s^4 + 3s^3 - 33s^2 + 2s - 40. Let (L, I, R) be defined as follows. L is the number of roots of p(s) with negative real parts. I is the number...

hardanswer key
2025 Q53

Consider a system where $x_1(t)$, $x_2(t)$, and $x_3(t)$ are three internal state signals and $u(t)$ is the input signal. The differential equations governing the system are given...

hardanswer key
2025 Q56

Consider a system represented by the block diagram shown below. Which of the following signal flow graphs represent(s) this system? Choose the correct option(s).

mediumanswer key
2024 Q12

In the context of Bode magnitude plots, 40 dB/decade is the same as ________.

easy
2024 Q13

In the feedback control system shown in the figure below $G(s) = \frac{6}{s(s+1)(s+2)}$. $R(s), Y(s)$, and $E(s)$ are the Laplace transforms of $r(t), y(t)$, and $e(t)$, respective...

medium
2024 Q37

Consider a unity negative feedback control system with forward path gain G(s) = K / ((s+1)(s+2)(s+3)) as shown. The impulse response of the closed-loop system decays faster than e⁻...

hard
2024 Q38

A satellite attitude control system, as shown below, has a plant with transfer function $G(s) = \frac{1}{s^2}$ cascaded with a compensator $C(s) = \frac{K(s+\alpha)}{s+4}$, where K...

hard
2024 Q53

Consider a system $S$ represented in state space as $\frac{dx}{dt} = \begin{bmatrix} 0 & -2 \\ 1 & -3 \end{bmatrix}x + \begin{bmatrix} 1 \\ 0 \end{bmatrix}r, y=[2 \ -5]x$. Which of...

hard
2023 Q25

The open loop transfer function of a unity negative feedback system is G(s) = k / (s(1+sT₁)(1+sT₂)), where k, T₁ and T₂ are positive constants. The phase cross-over frequency, in r...

medium
2023 Q41

A closed loop system is shown in the figure where k > 0 and α > 0. The steady state error due to a ramp input (R(s) = α/s²) is given by

medium
2023 Q42

In the following block diagram, R(s) and D(s) are two inputs. The output Y(s) is expressed as Y(s) = G₁(s)R(s) + G₂(s)D(s). G₁(s) and G₂(s) are given by

medium
2023 Q57

The asymptotic magnitude Bode plot of a minimum phase system is shown in the figure. The transfer function of the system is $G(s) = \frac{k(s+z)^a}{s^b (s+p)^c}$, where k, z, p, a,...

hard
2019 Q32

The block diagram of a system is illustrated in the figure shown, where X(s) is the input and Y(s) is the output. The transfer function H(s) = \frac{Y(s)}{X(s)} is

medium
2019 Q33

Let the state-space representation of an LTI system be $\dot{x}(t) = A x(t) + B u(t)$, $y(t) = C x(t) + d u(t)$ where A, B, C are matrices, d is a scalar, u(t) is the input to the...

hard
2019 Q42

Consider a unity feedback system, as in the figure shown, with an integral compensator $\frac{K}{s}$ and open-loop transfer function $G(s) = \frac{1}{s^2 + 3s + 2}$ where K > 0. Th...

hard
2018 PYQ

The state equation and the output equation of a control system are given below: $$\mathop x\limits^. = \left[ {\matrix{ { - 4} & { - 1.5} \cr 4 & 0 \cr } } \right]x + \left[ {\matr...

mediumanswer key
2017 PYQ

Consider the state space realization $$$\left[ {\matrix{ {\mathop x\limits^ \bullet } & {\left( t \right)} \cr {\mathop x\limits^ \bullet } & {\left( t \right)} \cr } } \right] = \...

easy
2016 PYQ

Match the inferences X, Y, and Z, about a system, to the corresponding properties of the elements of first column in Routh's Table of the system characteristic equation. X: The sys...

easyanswer key
2007 PYQ

The transfer function of a plant is $$$T\left(s\right)=\frac5{\left(s+5\right)\left(s^2+s+1\right)}$$$ The second-order approximation of T (s) using dominant pole concept is:

easyanswer key
2004 PYQ

The state variable equations of a system are: $$${\mathop {{x_1} = - 3{x_1} - x}\limits^ \bullet _2} + u$$$ $$${\mathop x\limits^ \bullet _2} = 2{x_1}$$$ $$$y = {x_1} + u.$$$ The s...

mediumanswer key
2003 PYQ

The zero, input response of a system given by the state space equation $$$\left[ {{{\mathop {{x_1}}\limits^ \bullet } \over {\mathop {{x_2}}\limits^ \bullet }}} \right] = \left[ {\...

mediumanswer key
1999 PYQ

The system mode described by the state equations $$$X = \left( {\matrix{ 0 & 1 \cr 2 & { - 3} \cr } } \right)x + \left( {\matrix{ 0 \cr 1 \cr } } \right)u,y = \left[ {\matrix{ 1 &...

easyanswer key
1998 PYQ

Consider a feedback control system with loop transfer function $$$G\left(s\right)H\left(s\right)=\frac{K\left(1+0.5s\right)}{s\left(1+s\right)\left(1+2s\right)}$$$ The type of the...

easyanswer key
1994 PYQ

The 3-dB bandwidth of a typical second- order system with the transfer function $${{C\left( s \right)} \over {R(s)}} = {{\omega _n^2} \over {{s^2} + 2\xi {\omega _n}s + \omega _n^2...

mediumanswer key
1990 PYQ

An electromechanical closed-loop control system has the following characteristic equation $$s^3+6Ks^2+\left(K+2\right)s+8\;=\;0$$, where K is the forward gain of the system.The con...

mediumanswer key