GATE EC|| CONTROL SYSTEM || FREQUENCY DOMAIN ANALYSIS|| PYQS(2000-2025)

Last Updated :
Discuss
Comments

Question 1

An amplifier with resistive negative feedback has two left-half plane poles in its open-loop transfer function. The amplifier

(GATE 2001 || EC || MCQ||1 MARK)

  • will always be unstable at high frequency

  • will be stable for all frequency

  • may be unstable, depending on the feedback factor

  • will oscillate at low frequency

Question 2

[2000 : 1 Mark]

Which one of the following polar diagrams corresponds to a lag network?


(GATE 2001 || EC || MCQ||1 MARK)

  • Screenshot-2025-08-26-105800


  • Screenshot-2025-08-26-122957


  • Screenshot-2025-08-26-123011


  • Screenshot-2025-08-26-123016


Question 3

In the system shown below, x(t) = (sin t)u(t). In a steady state, the response y(t) will be

Screenshot-2025-08-26-123650


(GATE 2006 || EC || MCQ||1 MARK)

  • [Tex]\frac{1}{\sqrt{2}} \sin \left( t - \frac{\pi}{4} \right)[/Tex]

  • [Tex]\frac{1}{\sqrt{2}} \sin \left( t + \frac{\pi}{4} \right)[/Tex]

  • [Tex]\frac{1}{\sqrt{2}} e^{-t} \sin t[/Tex]

  • [Tex]\sin t - \cos t[/Tex]

Question 4

The frequency response of a linear, time-invariant system is given by

[Tex]H(f) = \frac{5}{1 + j 10 \pi f}[/Tex]

The step response of the system is

(GATE 2007 || EC || MCQ||1 MARK)

  • [Tex]H(f) = \frac{5}{1 + j 10 \pi f}[/Tex]


  • [Tex]5(1 - e^{-t/5}) u(t)[/Tex]

  • [Tex]\frac{1}{5} (1 - e^{-5t}) u(t)[/Tex]



  • [Tex]\frac{1}{5} (1 - e^{-t/5}) u(t)[/Tex]

Question 5

Consider two transfer functions and

[Tex]G_1(s) = \frac{1}{s^2 + as + b}[/Tex]

[Tex]G_2(s) = \frac{s}{s^2 + as + b}[/Tex]

The 3-dB bandwidths of their frequency responses are respectively,


(GATE 2006 || EC || MCQ||1 MARK)

  • [Tex]\sqrt{a^2 - 4b}, \sqrt{a^2 + 4b}[/Tex]

  • [Tex]\sqrt{a^2 + 4b}, \sqrt{a^2 - 4b}[/Tex]


  • [Tex]\sqrt{a^2 - 4b}, \sqrt{a^2 - 4b}[/Tex]

  • [Tex]\sqrt{a^2 + 4b}, \sqrt{a^2 + 4b}[/Tex]

Question 6

Consider the pole-zero plot shown in the figure. Identify the type of filter represented by this pole-zero configuration.


Screenshot-2025-08-26-145108
  • Low pass filter

  •  High pass filter

  • Band pass filter

  • Notch filter

Question 7


A system with a transfer function [Tex]G(s) = \frac{(s^2 + 9)(s + 2)}{(s + 1)(s + 3)(s + 4)}[/Tex]

is excited by sin(ωt). The steady-state output of the system is zero at


(GATE 2001 || EC || MCQ||1 MARK)

  • [Tex]\omega = 1[/Tex] rad/s

  • [Tex]\omega = 2[/Tex] rad/s


  • [Tex]\omega = 3[/Tex] rad/s

  • [Tex]\omega = 4[/Tex] rad/s

Question 8

The transfer function of a mass-spring-damper system is given by

[Tex]G(s) = \frac{1}{Ms^2 + Bs + K}[/Tex]

The frequency response data for the system are given in the following table.

FrequencyMagnitude (dB)Phase (°)
0.01-18.5-0.2
0.1-18.5-1.3
0.2-18.4-2.6
1-16.0-16.9
2-11.4-89.4
3-21.5-151.0
5-32.8-167.0
10-45.3-174.5

The unit step response of the system approaches a steady-state value of ______.

(GATE 2015 || EC || MCQ||2 MARK)

  • 0.12

Question 9

For a unity feedback control system with the forward path transfer function, the peak resonant magnitude M of the closed-loop frequency response is 2. The corresponding value of the gain K (correct to two decimal places) is.(GATE 2018 || EC || MCQ||2 MARK)

  • 14.92

Question 10

A system with a transfer function

is subjected to an input 5 cos 3t. The steady-state output of the system is

The value of a is ……

(GATE 2005 || EC || MCQ||2 MARK)

  • 4

Tags:

There are 14 questions to complete.

Take a part in the ongoing discussion